Home About us Contact
|
Home About us Contact | ||
|
|
||
Millimeters
Kinds of Millimeters Selected AbstractsReflection and penetration depth of millimeter waves in murine skinBIOELECTROMAGNETICS, Issue 5 2008S.I. Alekseev Abstract Millimeter (mm) wave reflectivity was used to determine murine skin permittivity. Reflection was measured in anesthetized Swiss Webster and SKH1-hairless mice in the 37,74 GHz frequency range. Two skin models were tested. Model 1 was a single homogeneous skin layer. Model 2 included four skin layers: (1) the stratum corneum, (2) the viable epidermis plus dermis, (3) fat layer, and (4) muscle which had infinite thickness. We accepted that the permittivity of skin in the mm wave frequency range results from the permittivity of cutaneous free water which is described by the Debye equation. Using Fresnel equations for reflection we determined the skin parameters best fitting to the reflection data and derived the permittivity of skin layers. The permittivity data were further used to calculate the power density and specific absorption rate profiles, and the penetration depth of mm waves in the skin. In both murine models, mm waves penetrate deep enough into tissue to reach muscle. In human skin, mm waves are mostly absorbed within the skin. Therefore, when extrapolating the effects of mm waves found in animals to humans, it is important to take into account the possible involvement of muscle in animal effects. Bioelectromagnetics 29:340,344, 2008. © 2008 Wiley-Liss, Inc. [source] Effect of millimeter wave irradiation on tumor metastasisBIOELECTROMAGNETICS, Issue 4 2006Mahendra K. Logani Abstract One of the major side effects of chemotherapy in cancer treatment is that it can enhance tumor metastasis due to suppression of natural killer (NK) cell activity. The present study was undertaken to examine whether millimeter electromagnetic waves (MMWs) irradiation (42.2 GHz) can inhibit tumor metastasis enhanced by cyclophosphamide (CPA), an anticancer drug. MMWs were produced with a Russian-made YAV-1 generator. Peak SAR and incident power density were measured as 730,±,100 W/kg and 36.5,±,5 mW/cm2, respectively. Tumor metastasis was evaluated in C57BL/6 mice, an experimental murine model commonly used for metastatic melanoma. The animals were divided into 5 groups, 10 animals per group. The first group was not given any treatment. The second group was irradiated on the nasal area with MMWs for 30 min. The third group served as a sham control for group 2. The fourth group was given CPA (150 mg/kg body weight, ip) before irradiation. The fifth group served as a sham control for group 4. On day 2, all animals were injected, through a tail vein, with B16F10 melanoma cells, a tumor cell line syngeneic to C57BL/6 mice. Tumor colonies in lungs were counted 2 weeks following inoculation. CPA caused a marked enhancement in tumor metastases (fivefold), which was significantly reduced when CPA-treated animals were irradiated with MMWs. Millimeter waves also increased NK cell activity suppressed by CPA, suggesting that a reduction in tumor metastasis by MMWs is mediated through activation of NK cells. Bioelectromagnetics 27:258,264, 2006. © 2006 Wiley-Liss, Inc. [source] Frameworks by Solvent-Free Synthesis of Rare Earth Chlorides with Molten 1,3-Benzodinitrile and Tailoring of the Particle Size: ,3[LnCl3{1,3-C6H4(CN)2}], Ln = Y, Dy, Ho, Er, YbEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2010Christoph J. Höller Abstract The solvent-free melt reactions of anhydrous rare earth trichlorides with molten 1,3-benzodinitrile [1,3-C6H4(CN)2, C8H4N2] result in isophthalonitrile frameworks of the rare earth elements. The particle size of the products can bevaried from the millimeter to the nanometer scale (down to 50,400 nm) depending on the synthesis conditions. Thus, these network structures are among the very few coordination polymers that can be synthesized as nanoparticles. A constitution of 1:1 concerning LnCl3/1,3-C6H4(CN)2 is found for Y (1), Dy (2), Ho (3), Er (4), and Yb (5) in isotypic,3[LnCl3{1,3-C6H4(CN)2}]. The ligand 1,3-C6H4(CN)2 functions both as chemical scissors and replaces chloride linkages by degrading the rare earth chloride structures, and subsequently forms new 3D-framework structures. They consist of strands of chlorido-coordinated lanthanide atoms, which are linked in two dimensions by 1,3-C6H4(CN)2 molecules. Compounds 1,5 were obtained as single crystals from the melt reaction, and their crystal structures were determined by single-crystal X-ray analysis. They can also be obtained as nanocrystalline materials from a ball mill treatment, identified by electron microscopy (REM) and EDX analysis. [source] Bulk Nanoporous Metal for ActuationADVANCED ENGINEERING MATERIALS, Issue 8 2010Hai-Jun Jin Abstract Nanoporous metals prepared by controlled chemical or electrochemical corrosion of alloys can provide prototypical manifestations of bulk nanostructured material. Samples are readily prepared with dimensions at the millimeter or centimeter scale, while at the same time the microstructure is a homogeneous array of interpenetrating solid skeleton phase and pore channels with a characteristic size that can reach down to below 5,nm. The interest in nanoporous metals as functional materials derives from recent observations of unique materials behavior resulting from their extremely small structure size and their open porosity with large volume-specific surface area. As an example, this article discusses the possible use of nanoporous metal for actuation. [source] Soft Mechanical Sensors Through Reverse Actuation in Polypyrrole,ADVANCED FUNCTIONAL MATERIALS, Issue 16 2007Y. Wu Abstract The phenomenon of voltage generated from a soft sensor using polypyrrole in response to mechanical deformation is described and investigated. The sensor consists of two polypyrrole layers in contact with an electrolyte and operates in bending mode in air. The magnitude and sign of the induced voltage was found to depend on the type of dopant counter-ions and the nature of the surrounding electrolyte. The mechanical sensor response is shown to be a "reverse actuation", generating millivolt signals for millimeter sized deflections or ,,1000,C,m,3 charge for 1,% strain in the polypyrrole layer. A model based on ,Deformation Induced Ion Flux' has been proposed whereby the strain induced volume change in the polymer produces a shift in the Donnan equilibrium between mobile dopant ions inside the polymer and in the external electrolyte. A simple thermodynamic model provides reasonable estimates of the size of the voltage and charge produced. [source] Optimum packing factor of the stack in a standing-wave thermoacoustic prime moverINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 8 2002Limin Qiu Abstract A bench consisting of a pulse tube refrigerator driven by a standing-wave thermoacoustic prime mover has been set up to study the relationship among stack, regenerator and working fluids. The stack of the thermoacoustic prime mover is packed with dense-mesh wire screens because of their low cost and easy manufacture. The effect of the packing factor in the stack on onset temperature, refrigeration temperature and input power is explored. The optimum packing factor of 1.15 pieces per millimeter has been found experimentally, which supplies an empirical value to satisfy a compromise for enhancing thermoacoustic effect, decreasing heat conduction and fluid-friction losses along the stack. The pulse tube cooler driven by the thermoacoustic prime mover is able to obtain refrigeration temperatures as low as 138 and 196K with helium and nitrogen, respectively. Copyright © 2002 John Wiley & Sons, Ltd. [source] Superiority of a functional leukocyte adhesiveness/aggregation test over the white blood cell count to discriminate between mild and significant inflammatory response in patients with acute bacterial infectionsJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 4 2002Ori Rogowski Abstract Electronic cell counters may underestimate the white blood cell count (WBCC) in the presence of aggregated leukocytes. In the present study we focused on the possibility of using a functional, as opposed to an anatomic, count to circumvent this eventual underestimation. A model of bacterial infection was used because of the importance of leukocytosis in the physician's clinical decision-making process. There were 35 patients with low C-reactive protein (CRP) concentrations (0.5,4.9 mg/dL), 45 with intermediate (5,9.9 mg/dL), and 120 with relatively high (>10 mg/dL) CRP concentrations. A significant (P=0.008) difference was noted between the state of leukocyte adhesiveness/aggregation in the peripheral blood of individuals with low CRP concentrations (3.5%±4.3%) and those with high CRP concentrations (7.4%±8%), while there was no significant difference in the respective number of WBCs per cubic millimeter (cmm) (11,600 ± 5,500 and 14,000 ± 7,200, respectively). We raise the possibility that a functional test might be superior over an anatomic count in patients with acute bacterial infection and a significant acute phase response. © 2002 Wiley-Liss, Inc. [source] 60-GHz bandpass filter with ACMRC resonator fabricated using 0.18-,m CMOS technologyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2009Chia-Hsieh Liu Abstract This article presents design and implementation of a 60-GHz millimeter- wave on-chip bandpass filter using a 0.18-,m standard CMOS process. The asymmetric compact microstrip resonator cell structure is used to design the filter with two transmission zeros. The input and output capacitors using multilayer coupling are added to create the passband. The die size of the chip is 0.85 × 0.64 mm2. The filter has a 3-dB bandwidth of about 15 GHz at the center frequency of 64 GHz. The measured insertion loss of the center-frequency is about 3.9 dB and the return loss is better than 10 dB within passband. The designed on-chip filter is useful for the integrated design of the 60-GHz CMOS single-chip RF transceiver. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 597,600, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24119 [source] Optical mm-wave generation based on phase modulation along with optical filteringMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2007Jianxin Ma Abstract We have investigated the generation and transmission of optical millimeter (mm)-wave signal based on optical phase modulator (PM) and fiber Bragg grating (FBG) filter. With an optimized modulation depth of PM and a higher carrier suppression ratio via a notch filter, the generated optical mm-wave can be transmitted over a long-distance without fading. We have also theoretically analyzed the impact of time shift on the eye closure of optical and electrical signal due to the fiber dispersion, which is well in accord with the experimental results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1787,1793, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22622 [source] To extend delivery distance of the optical MM-wave generated by DSB modulation and vestigial sideband filteringMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 5 2006Jianguo Yu Abstract Due to RF fading effect caused by fiber dispersion in standard single-mode fiber (SSMF), the maximum delivery distance in SSMF for the optical millimeter (mm)-wave signals generated by the double-sideband modulation scheme is shorter than 2 km at a power penalty of 2 dB. We experimentally demonstrate that the maximum transmission distance can be largely extended after using vestigial sideband (VSB) filtering. When we use VSB filtering technique, the transmission distance for the mm-wave signals is extended more than 40 km at a power penalty of 2 dB. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1003,1004, 2006; Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.21548 [source] Seeing right through you: Applications of optical imaging to the study of the human brainPSYCHOPHYSIOLOGY, Issue 4 2003Gabriele Gratton Abstract A new set of techniques allows for the study of brain function by near-infrared light, exploiting two optical phenomena: Changes in light absorption are determined by changes in the concentration of substances like oxy- and deoxy-hemoglobin, and changes in light scattering occur as a consequence of variations of properties of membranes and corpuscles in the neural tissue. Methods based on light absorption can be used to study hemodynamic changes in the brain, whereas those based on light scattering can be used to study neuronal activity and to provide anatomical information at a cellular and subcellular level. Three optical imaging approaches can be used to study living tissue: reflection, optical coherence tomography (OCT), and photon migration. These three approaches vary in their penetration (from less than a millimeter for reflection to up to 3,5 cm for photon migration) and spatial resolution (from a micron level for reflection and OCT to a millimeter and centimeter level for photon migration). This issue includes a collection of articles reviewing applications of these technologies to the study of brain and other bodily functions in humans. [source] Assessment of Proliferating Cell Nuclear Antigen Activity Using Digital Image Analysis in Breast Carcinoma Following Magnetic Resonance-Guided Interstitial Laser PhotocoagulationTHE BREAST JOURNAL, Issue 5 2003Soheila Korourian MD Abstract: This study examines proliferative activity in tumor cells of patients with histologically documented invasive breast carcinoma treated with magnetic resonance-guided interstitial laser photocoagulation (MR-GILP). Immunohistochemical marker for proliferating cell nuclear antigen (PCNA), a nuclear protein abundant in actively proliferating cells, is used. The study demonstrates the effectiveness of MR-GILP in ablating tumor cells of infiltrating breast cancer. The diagnosis of infiltrating breast carcinoma was confirmed by core needle biopsies. Using a specially designed magnetic resonance imaging (MRI) device, rotating delivery of excitation off-resonance (RODEO), tumors were measured ranging from 1.8 to 4.0 cm in greatest dimension. Seven formalin-fixed, paraffin-embedded archival tissues from seven patients with infiltrating carcinoma, status post-MR-GILP, were analyzed. Using PCNA immunoperoxidase (Biomeda Corp.), the proliferative capability of the remaining tumor cells around the focus of laser photocoagulation was determined. The lesions were digitally acquired using a Nikon Eclipse E800 microscope with an automated stage. Images were analyzed using Cool SNAP image editing software (version 1.0). Appropriate thresholds were set for positive staining and limited concentric radial measurements of equal area between all samples were compared at radial millimeter intervals from the center of laser ablation. The integrated area occupied by PCNA-positive cells per radial millimeter from the charcoal site (the center of the laser) increased as the distance from this site increased (a mean average at each radial measurement revealed: at the 1 mm radius the positive integrated area was 0.0024 mm2; at 2 mm, 0.0145 mm2; at 3 mm, 0.0351 mm2; at 4 mm, 0.0696 mm2; at 5 mm, 0.1025 mm2; and at 6 mm, 0.1263 mm2). MR-GILP is an effective mean of ablating breast carcinoma. This treatment option may represent an alternative to lumpectomy for a single lesion ,1 cm, or make patients with two separate lesions eligible for lumpectomy. [source] Lymphatic Neoangiogenesis in Human Renal Allografts: Results from Sequential Protocol BiopsiesAMERICAN JOURNAL OF TRANSPLANTATION, Issue 2 2007S. Stuht Neoangiogenesis of lymphatic vessels may be important for the cellular immune response in renal transplants. To determine the prevalence and chronology of lymph vessel proliferation and its relation to cellular infiltrates and allograft function, we analyzed sequential protocol biopsies (n = 162), taken at 6, 12 and 26 weeks after transplantation. Biopsies were stained with an antibody against podoplanin and lymphatic vessel density was quantified per square millimeter. The prevalence of lymph vessel-positive biopsies and the lymph vessel density were similar at 6, 12 and 26 weeks after transplantation. Biopsies with acute cellular rejection showed no significantly different lymph vessel density compared to those below the threshold for acute rejection or chronic allograft nephropathy. While lymphatic neoangiogenesis was equally prevalent in biopsies with and without infiltrates, the lymph vessel density was significantly higher in areas with cellular infiltrates than in areas without. Graft function at 1 year after transplantation was better in cases with lymph vessels in their infiltrates compared to cases with lymph vessel-free infiltrates. In conclusion, lymphangiogenesis not only shows a clear association with cellular infiltrates but might also have an impact on the pathogenicity of these cellular infiltrates. [source] Change in joint space width: Hyaline articular cartilage loss or alteration in meniscus?ARTHRITIS & RHEUMATISM, Issue 8 2006D. J. Hunter Objective To explore the relative contribution of hyaline cartilage morphologic features and the meniscus to the radiographic joint space. Methods The Boston Osteoarthritis of the Knee Study is a natural history study of symptomatic knee osteoarthritis (OA). Baseline and 30-month followup assessments included knee magnetic resonance imaging (MRI) and fluoroscopically positioned weight-bearing knee radiographs. Cartilage and meniscal degeneration were scored on MRI in the medial and lateral tibiofemoral joints using a semiquantitative grading system. Meniscal position was measured to the nearest millimeter. The dependent variable was joint space narrowing (JSN) on the plain radiograph (possible range 0,3). The predictor variables were MRI cartilage score, meniscal degeneration, and meniscal position measures. We first conducted a cross-sectional analysis using multivariate regression to determine the relative contribution of meniscal factors and cartilage morphologic features to JSN, adjusting for body mass index (BMI), age, and sex. The same approach was used for change in JSN and change in predictor variables. Results We evaluated 264 study participants with knee OA (mean age 66.7 years, 59% men, mean BMI 31.4 kg/m2). The results from the models demonstrated that meniscal position and meniscal degeneration each contributed to prediction of JSN, in addition to the contribution by cartilage morphologic features. For change in medial joint space, both change in meniscal position and change in articular cartilage score contributed substantially to narrowing of the joint space. Conclusion The meniscus (both its position and degeneration) accounts for a substantial proportion of the variance explained in JSN, and the change in meniscal position accounts for a substantial proportion of change in JSN. [source] Small nerve fiber involvement in systemic lupus erythematosus: A controlled studyARTHRITIS & RHEUMATISM, Issue 5 2002Roald Omdal Objective To determine if patients with systemic lupus erythematosus (SLE) may have a peripheral neuropathy involving unmyelinated and small, myelinated nerve fibers, by immunostaining epidermal nerve fibers (ENF) in skin biopsy samples for the panaxonal marker, protein gene product 9.5 (PGP 9.5). Methods Fifteen consecutive and nonselected SLE patients and 15 age- and sex-matched controls were included in the study. The age of the patients ranged from 25 years to 65 years, with a mean ± SD age of 47.3 ± 10.2 years and a disease duration of 2,28 years (mean ± SD 14.8 ± 8.6 years). Two 3-mm skin biopsy samples were obtained with a punch needle ,10 cm superior to the lateral malleolus of the right leg and immunostained with 0.1% rabbit polyclonal antibodies to human PGP 9.5. The number of ENF per millimeter was counted and recorded as the mean ± SD of counts in six 50-,m sections, 3 from each of the 2 biopsy samples. Results The mean number of ENF per mm in patients with SLE was 8.0 ± 1.5 (range 5.0,9.9), while the matched controls had 12.2 ± 3.8 ENF per mm (range 6.8,18.6) (P = 0.0006). Conclusion This study indicates that a small fiber involvement in patients with SLE may be responsible for the prevalent neuropathic symptoms and impaired warm sense that is observed in such patients. [source] 4242: Elschnig pearl formation and disappearanceACTA OPHTHALMOLOGICA, Issue 2010N HIRNSCHALL Purpose To observe and analyze morphological changes of Elschnig pearls in eyes with after-cataract. Methods Pseudophakic eyes with pronounced regeneratory posterior capsule opacification were included in the prospective studies. In the first study the natural course of Elschnig pearls was observed during days and weeks. In the second study morphological changes immediately after a Nd:YAG-capsulotomy were observed. And in two further studies the Nd:YAG laser capsulotomy was modified and the effect on Elschnig pearls was observed. Results In the first study, in total 6309 Elschnig pearls (85 eyes) were analyzed. On average, four pearls were found per square millimeter (range, 0.2-9.7/mm2) with a mean cumulative area of 0.66 mm2) (range, 0.03-2.18 mm2) of all marked pearls per eye and follow-up. The mean pearl size was 9630 microm2 (range, 2390-33,745 microm2) at baseline. The mean change of a pearl per day was 583 microm2 (range, 175-1631 microm2) or a 6% change in area. In the second study in total, 2431 Elschnig pearls (20eyes) were observed. Of these, 535 pearls (30.6%) disappeared, and 503 pearls (27.6%) survived on the remaining capsule peripheral to the capsulotomy opening. Conclusion Elschnig pearls disappear and appear within days. The degree of progression and regression varies greatly between eyes. Capsulotomy had an immediate impact on the morphology of PCO outside the capsulotomy opening. Knowledge about Elschnig pearl turnover may be of importance for attempts to modulate lens epithelial regeneration or lens regrowth and for lens-refilling procedures. [source] Atypical Clinical Features of Pediatric AppendicitisACADEMIC EMERGENCY MEDICINE, Issue 2 2007Theresa Becker DO Background The diagnosis of appendicitis remains challenging in children. Delays in diagnosis, or misdiagnosis, have important medical and legal implications. The typical, or classic, presentation of pediatric appendicitis has been modeled after adult disease; however, many children present atypically with subtle findings or unusual signs. Objectives To determine the frequency of atypical clinical features among pediatric patients with appendicitis and to investigate which atypical features are the strongest negative predictors for appendicitis among patients being evaluated for appendicitis. Methods Children and adolescents with suspected appendicitis were enrolled over 20 consecutive months. Pediatric emergency physicians completed standardized data collection forms on eligible patients. Final diagnosis was determined by pathology or follow-up telephone call. Typical and atypical findings were defined strictly a priori. Results Seven hundred fifty-five patients were enrolled. The median age was 11.9 years (interquartile range [IQR]: 8.5, 14.9 yr); 36% of patients were diagnosed with appendicitis. Among patients with appendicitis, the most common atypical features included absence of pyrexia (83%), absence of Rovsing's sign (68%), normal or increased bowel sounds (64%), absence of rebound pain (52%), lack of migration of pain (50%), lack of guarding (47%), abrupt onset of pain (45%), lack of anorexia (40%), absence of maximal pain in the right lower quadrant (32%), and absence of percussive tenderness (31%). Forty-four percent of patients with proven appendicitis had six or more atypical characteristics. The median number of atypical features for patients with proven appendicitis was five (IQR: 4.0, 7.0). The greatest negative predictors, on the basis of likelihood ratios, were as follows: white blood cell count (WBC) of <10,000 per cubic millimeter (likelihood ratios [LR], 0.18), absolute neutrophil count (ANC) of <7,500 per cubic millimeter (LR, 0.35), lack of percussive tenderness (LR, 0.50), lack of guarding (LR, 0.63), and no nausea or emesis (LR, 0.65). Conclusions Appendicitis in pediatric patients is difficult to diagnose because children present with a wide variety of atypical clinical features. Forty-four percent of patients with appendicitis presented with six or more atypical features. Two atypical features are the strongest negative predictors of appendicitis in children: WBC of <10,000 per cubic millimeter and an ANC of <7,500 per cubic millimeter. [source] Botulinum-A Toxin Treatment of the Lower Eyelid Improves Infraorbital Rhytides and Widens the EyeDERMATOLOGIC SURGERY, Issue 8 2001Timothy Corcoran Flynn MD Botulinum-A exotoxin (BTX-A) can be used cosmetically to improve rhytides, particularly of the upper one-third of the face. In this study, fifteen women had BTX-A (BOTOX, Allergan, Inc.) injected into the orbicularis oculi muscle. One lower eyelid received two units just subdermally in the midpupillary line three millimeters below the ciliary margin. The opposite periocular area received two units BTX-A in the lower eyelid with 12 units BTX-A injected into the lateral orbital ("crow's foot") area. Three injections of four units each were placed 1.5 cm from the lateral canthus, each 1 cm apart. Patients and physicians independently evaluated the degree of improvement (grade 0 = no improvement, grade 1 = mild improvement, grade 2 = moderate improvement, and grade 3 = dramatic improvement). An independent photographic analysis was performed. Patients reported a grade of 0.73 when two units were injected alone into the lower lid, and a grade of 1.9 when the lower eyelid and the lateral orbital areas were injected. Physician assessment was grade 0.7 with injection of the eyelid alone and grade 1.8 with injection of the lower eyelid and lateral orbital area. Single investigator photographic analysis demonstrated that 40% of the subjects who had injection of the lower eyelid alone had an increased palpebral aperture (IPA), while 86% of the subjects who had injection of the lower eyelid and lateral orbital area had an IPA. Subjects receiving two units alone had an average 0.5 mm IPA and a mean 1.3 mm IPA at full smile. Concomitant treatment of the lateral orbital area produced a mean 1.8 mm IPA at rest and a mean 2.9 mm IPA at full smile. The results were more notable in the Asian eye. Two units of BTX-A injected into the lower eyelid orbicularis oculi muscle improves infraorbital wrinkles, particularly when used in combination with BTX-A treatment of the lateral orbital area. [source] Estimation of temporal variation in splash detachment in two Japanese cypress plantations of contrasting ageEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2010Y. Wakiyama Abstract To elucidate splash erosion processes under natural rainfall conditions, temporal variations in splash detachment were observed using a piezoelectric saltation sensor (H11B; Sensit Co., Portland, ND, USA). Preliminary laboratory tests of Sensit suggested that they were suitable for field observations. Field observations were conducted between July and September 2006 in 21- and 36-year-old Japanese cypress (Chamaecyparis obtusa) plantations with mean stand heights of 9·2,m and 17·4,m, respectively. Splash detachment (in g m,2) was measured seven times using splash cups, and raindrop kinetic energy (in J,m,2,mm,1) in both stands was measured using laser drop-sizing (LD) gauges. Sensit was installed to record saltation counts, which were converted to temporal data of splash detachment (splash rate; in g m,2 10,min,1) using the relationship between splash detachment and saltation counts. Surface runoff was monitored using runoff plots of 0·5,m width and 2·0,m length to obtain temporal data of flow depth (in millimeters). Both total splash detachment and raindrop kinetic energy were larger in the older stand. Increased splash rates per unit throughfall were found in both stands after rainless durations longer than approximately one day in both stands. However, a lower splash rate was found in the 21-year stand after rainfall events. During extreme rainstorms, the 21-year stand showed a low runoff rate and a decline in the splash rate, while the 36-year stand showed a higher splash rate and increased flow depth. The piezoelectric sensor proved to be a useful means to elucidate splash erosion processes in field conditions. Copyright © 2010 John Wiley & Sons, Ltd. [source] Microbiotic crusts as biomarkers for surface stability and wetness duration in the Negev DesertEARTH SURFACE PROCESSES AND LANDFORMS, Issue 12 2009Giora J. Kidron Abstract Microbiotic crusts play an important role in arid and semi-arid regions. Yet, very little information exists regarding the factors that impact their development. In an attempt to assess the main factors that may determine their growth, measurements of the amount of fines (silt and clay), rain, moisture content, wetness duration and wind erosion and deposition were carried out along a 12 station transect within a partially crusted dune field in the western Negev Desert and compared to the crust cover and chlorophyll content. Surface stability was the only variable that exhibited significant relationship with crust cover while daylight wetness duration exhibited strong positive relationship (r2 = 0·92,0·99) with the crust's chlorophyll content. The data point out that microbiotic crusts may serve as a useful biomarker for surface stability. While wetness duration and wind will control crust cover and the crust chlorophyll content in semi-stable habitats (with absolute annual change in sand level of 2,3 mm), stable habitats (absolute change <1 mm) will be controlled primarily by moisture, while habitats with low surface stability (absolute change of tens and hundreds of millimeters) will be primarily controlled by wind. Furthermore, owing to the strong positive relationship between daylight wetness duration and the crust's chlorophyll content, the crust may serve as a useful biomarker for the quantification of surface wetness duration. Copyright © 2009 John Wiley & Sons, Ltd. [source] 5 DIAGNOSTIC PITFALLS IN THE ECHOCARDIOGRAPHIC EVALUATION OF HYPERTROPHIC OBSTRUCTIVE CARDIOMYOPATHY (HOCM) REFERRED FOR CATHETER INTERVENTIONAL THERAPYECHOCARDIOGRAPHY, Issue 1 2004G. Beer Introduction: Generally, the diagnosis of typical HOCM with subaortic obstruction and a dynamic pressure gradient across the left ventricular outflow tract is made by noninvasive diagnostic procedures with great certainty by employing transthoracic (TTE) and/or transoesophageal (TEE) echocardiography. However, in patients with asymmetric septal hypertrophy pitfalls in echocardiographic examination may arise from several additional diseases as described in casuistic reports. To date systematic investigations in patients referred for catheter interventional therapy of HOCM are lacking. Patients and Methods: Therefore we investigated for the first time in a systematic study 200 symptomatic patients. (180 consecutive and 20 nonconsecutive patients; functional class 3 or 4 according to NYHA) with HOCM who were referred for this new catheter interventional therapy. In all patients TTE, bicycle exercise Doppler echocardiography and multiplane TEE were performed. Results: In 4 of 180 consecutive patients. (2.2%) discrete subvalvular membranous aortic stenosis (DSAS) (3 female patients and 1 male patient; age 20 to 58 years; mean septal diameter 19 mm; Sam-like motion in all 4 patients) was made. In all cases the diagnosis could be confirmed by surgical treatment. TEE evaluation was of crucial importance with demonstration of a typical subvalvular membrane that was situated a few millimeters below the aortic valve. In all cases a typical asymmetric septal hypertrophy mimicking HOCM was seen. Additionally, in 2 patients there was a conincidence of severe symptomatic valvular aortic stenosis and HOCM and in 1 patient a tunnel type of subvalvular aortic stenosis was present. Conclusion: These results show the potential pitfalls in echocardiographic diagnosis of HOCM. Especially, the frequency of DSAS in symptomatic patients referred for HOCM is unexpectedly high (2.2%). Especially in patients in whom TTE is of insufficient quality, investigation employing multiplane TEE with careful evaluation of the small poststenotic subvalvular area in HOCM is of crucial importance. This is of special significance prior to catheter interventional therapy, because in these patients surgical treatment is mandatory. [source] Effectiveness of very thin soil layers in chemical release from bed sedimentENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2001Bryan Talbert The chemical containment effectiveness of both the natural recovery and the "particle broadcasting" processes for remediating contaminated bed-sediments depend upon very thin soil and/or sand layers millimeters in depth. Conventional capping for in situ chemical containment of bed-sediment or dredged material typically involves thick layers of 30 to 90 centimeters in depth. Few studies have been conducted with thin layers of candidate natural materials. A steady-state benzoic acid dissolution test apparatus and procedure, devised to realistically simulate bed-sediment chemo-dynamic conditions, was used to measure chemical flux through thin layers (1 to 8 mm) of soil, sand, and ideal porous media. The thin layers were found to be very effective. Flux reductions ranged from 81 to 96%, with fine sand being slightly better than top soil. Design algorithms developed for the thick layers used in conventional capping design will under predict the flux through very thin layers. Advective flow induced by surface roughness is proposed to explain the higher average measure d-to-predicted flux ratio of 1.67. [source] Ultrasonographic Screening of Clinically-suspected Necrotizing FasciitisACADEMIC EMERGENCY MEDICINE, Issue 12 2002Zui-Shen Yen MD Objective: To determine the accuracy of ultrasonography for the diagnosis of necrotizing fasciitis. Methods: This study was a prospective observational review of patients with clinically-suspected necrotizing fasciitis presenting to the emergency department of an urban (Taipei) medical center between October 1996 and May 1998. All patients underwent ultrasonographic examination, with the ultrasonographic diagnosis of necrotizing fasciitis based on the criterion of a diffuse thickening of the subcutaneous tissue accompanied by a layer of fluid accumulation more than 4 millimeters in depth along the deep fascial layer, when compared with the contralateral position on the corresponding normal limb. The final diagnosis of necrotizing fasciitis was determined by pathological findings for patients who underwent fasciotomy or biopsy results for patients managed nonoperatively. Results: Data were collected for 62 patients, of whom 17 (27.4%) were considered to suffer from necrotizing fasciitis. Ultrasonography revealed a sensitivity of 88.2%, a specificity of 93.3%, a positive predictive value of 83.3%, a negative predictive value of 95.4%, and an accuracy of 91.9% as regards the diagnosis of necrotizing fasciitis. Conclusions: Ultrasonography can provide accurate information for emergency physicians for the diagnosis of necrotizing fasciitis. [source] Effect of Hypervelocity Impact on Microcellular Ceramic Foams from a Preceramic PolymerADVANCED ENGINEERING MATERIALS, Issue 11 2003P. Colombo A promising material for hypervelocity impact shields in spacecraft and satellites has been found in lightweight microcellular SiOC foams. The foam stops the projectile and the debris from the impacted bumper facesheet within a few millimeters (see Figure for a cross-section of the crater) at speeds up to 5.1 km,s,1. The impacted SiOC ceramic did not react with incoming debris, and no phase transformation or compositional change was observed. [source] Contact Angle Analysis During the Electro-oxidation of Self-Assembled Monolayers Formed by n -OctadecyltrichlorosilaneADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Nicole Herzer Abstract The electrochemical oxidation process of self-assembled monolayers formed by n -octadecyltrichlorosilane (OTS) molecules on silicon wafers has been studied in a droplet of water by means of in situ water contact angle measurements. The application of different bias voltages between the substrate and a counter electrode placed into the droplet resulted in changes of the chemical nature of the monolayer, which yielded a significant alteration of the surfaces properties. Due to the changes of the wetting properties of the monolayer during the electro-oxidation process a change in the contact angles of the water droplet is concomitantly observed. This allows the in situ monitoring of the electro-oxidation process for large modified areas of several millimeters in diameter. The chosen approach represents an easy way to screen the major parameters that influence the oxidation process. Afterwards, the oxidized regions are characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) measurements, and atomic force microscopy (AFM) investigations to obtain more information about the electro-oxidation process. The observations are correlated to experimental results obtained for oxidations performed on a smaller dimension range in the water meniscus of a conductive, biased AFM tip. A good correlation of the results in the different dimension ranges could be found. [source] Azeotropic Binary Solvent Mixtures for Preparation of Organic Single CrystalsADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Xiaoran Li Abstract Here, a new approach is introduced to prepare large single crystals of ,-conjugated organic molecules from solution. Utilizing the concept of azeotropism, single crystals of tri-isopropylsilylethynyl pentacene (TIPS-PEN) with dimensions up to millimeters are facilely self-assembled from homogeneous solutions comprising two solvents with opposing polarities and a positive azeotropic point. At solvent compositions close to the azeotropic point, an abrupt transition of morphology from polycrystalline thin-films to large single crystals is found. How to adjust the initial ratio of the binary solvents so that the change in solvent composition during evaporation favors the specific H-aggregation and promotes an efficient self-assembly of TIPS-PEN is explained. The charge-carrier (hole) mobilities are substantially enhanced by a factor of 4 from the morphology of thin-films to large single crystals used as active layer in field-effect transistors. Additionally, this approach is extended to other ,,, stacked organic molecules to elucidate its broad applicability. [source] ALPINE AREAS IN THE COLORADO FRONT RANGE AS MONITORS OF CLIMATE CHANGE AND ECOSYSTEM RESPONSE,GEOGRAPHICAL REVIEW, Issue 2 2002MARK W. WILLIAMS ABSTRACT. The presence of a seasonal snowpack in alpine environments can amplify climate signals. A conceptual model is developed for the response of alpine ecosystems in temperate, midlatitude areas to changes in energy, chemicals, and water, based on a case study from Green Lakes Valley,Niwot Ridge, a headwater catchment in the Colorado Front Range. A linear regression shows the increase in annual precipitation of about 300 millimeters from 1951 to 1996 to be significant. Most of the precipitation increase has occurred since 1967. The annual deposition of inorganic nitrogen in wetfall at the Niwot Ridge National Atmospheric Deposition Program site roughly doubled between 1985,1988 and 1989,1992. Storage and release of strong acid anions, such as those from the seasonal snowpack in an ionic pulse, have resulted in episodic acidification of surface waters. These biochemical changes alter the quantity and quality of organic matter in high-elevation catchments of the Rocky Mountains. Affecting the bottom of the food chain, the increase in nitrogen deposition may be partly responsible for the current decline of bighorn sheep in the Rocky Mountains. [source] The Lisse Effect RevisitedGROUND WATER, Issue 6 2002Edwin P. Weeks The Lisse effect is a rarely noted phenomenon occurring when infiltration caused by intense rain seals the surface soil layer to airflow, trapping air in the unsaturated zone. Compression of air by the advancing front results in a pressure increase that produces a water-level rise in an observation well screened below the water table that is several times as large as the distance penetrated by the wetting front. The effect is triggered by intense rains and results in a very rapid water-level rise, followed by a recession lasting a few days. The Lisse effect was first noted and explained by Thal Larsen in 1932 from water-level observations obtained in a shallow well in the village of Lisse, Holland. The original explanation does not account for the increased air pressure pushing up on the bottom of the wetting front. Analysis of the effect of this upward pressure indicates that a negative pressure head at the base of the wetting front, ,f, analogous to that postulated by Green and Ampt (1911) to explain initially rapid infiltration rates into unsaturated soils, is involved in producing the Lisse effect. Analysis of recorded observations of the Lisse effect by Larsen and others indicates that the water-level rise, which typically ranges from 0.10 to 0.55 m, should be only slightly larger than |,f| and that the depth of penetration of the wetting front is no more than several millimeters. [source] Highly Ordered, Millimeter-Scale, Continuous, Single-Crystalline Graphene Monolayer Formed on Ru (0001)ADVANCED MATERIALS, Issue 27 2009Yi Pan A single-crystalline graphene monolayer is grown on a Ru(0001) surface by thermal annealing of a ruthenium single crystal containing carbon. The layer is highly ordered, continuous, and exhibits perfect crystallinity, with good long-range order on the order of millimeters (see figure). These findings offer high-quality graphene layers for fundamental research as well as large-scale graphene wafers for device fabrication and integration. [source] Two Japanese cases of lichen planus pigmentosus-inversusINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 7 2007Aki Kashima MD Case 1 was a 51-year-old Japanese woman. She presented with an asymptomatic brown macule located on the right axilla of 2 months' duration. The smooth macule was 2 cm in diameter with a sharp demarcation (Fig. 1A). Figure 1. Photographs of skin lesions in two patients. (A) Case 1. Well-circumscribed brown macule without an active red border in the central portion of the right axilla. (B) Case 2. Symmetric distribution of brown macules without an active red border in the popliteal fossae Case 2 was a 62-year-old Japanese man. He presented with asymptomatic, symmetric, gray,brown macules located on the groin, axillae, and popliteal region of 6 months' duration. The smooth macules were several millimeters to centimeters in diameter and sharply demarcated (Fig. 1B). Oral or nail lesions, previous inflammatory processes in affected areas, and internal malignancies were absent. A causal relationship with drugs, recent sun exposure, or trauma could not be identified. Findings for work-up, including blood cell count, fasting blood sugar levels, liver function, serum electrolyte levels, serum electrophoresis, urinalysis, antinuclear antibodies, and serological examinations for human hepatitis viruses and syphilis, were within normal limits or negative. The lesions gradually disappeared without medication within 6 months. Biopsy specimens showed a lymphocytic infiltrate with basal vacuolar changes and prominent melanin incontinence in the upper dermis (Fig. 2A). The band-like lymphocytic infiltrate was moderate in Case 1 and mild in Case 2. Immunohistochemistry showed infiltrative CD8+ T lymphocytes with keratinocytic damage, indicating cytotoxic injury of the keratinocytes (Fig. 2B). Both the epidermis and the upper dermis contained CD1a+ cells (Fig. 2C). The keratinocytes focally and weakly expressed HLA-DR (Fig. 2D). These findings were identical in samples from both patients. Figure 2. Light and immunohistochemical microphotographs. (A) Mild, band-like, lymphocytic infiltrate with basal vacuolar change and prominent melanin incontinence in the upper dermis with apoptosis or necrosis of keratinocytes. (B) Epidermal infiltrate of CD8+ T lymphocytes with keratinocytic damage. (C) CD1a+ cells in the upper dermis. (D) Keratinocytes focally and weakly express HLA-DR (original magnifications: A, ×200; B,D, ×400) [source] | |||||||||||||||||||||||||||||||||||||||||||