Lifetime

Distribution by Scientific Domains
Distribution within Chemistry

Kinds of Lifetime

  • average lifetime
  • carrier lifetime
  • emission lifetime
  • excited-state lifetime
  • exciton lifetime
  • fluorescence lifetime
  • individual lifetime
  • long lifetime
  • longer lifetime
  • luminescence lifetime
  • patient lifetime
  • positron lifetime
  • radiative lifetime
  • recombination lifetime
  • remaining lifetime
  • short lifetime
  • state lifetime
  • system lifetime

  • Terms modified by Lifetime

  • lifetime alcohol
  • lifetime alcohol intake
  • lifetime comorbidity
  • lifetime component
  • lifetime cost
  • lifetime data
  • lifetime depression
  • lifetime diagnosis
  • lifetime distribution
  • lifetime earning
  • lifetime exposure
  • lifetime fecundity
  • lifetime fitness
  • lifetime history
  • lifetime imaging
  • lifetime imaging microscopy
  • lifetime measurement
  • lifetime number
  • lifetime prediction
  • lifetime prevalence
  • lifetime ptsd
  • lifetime reproductive output
  • lifetime reproductive success
  • lifetime risk
  • lifetime sexual partner
  • lifetime spectroscopy
  • lifetime substance abuse
  • lifetime value
  • lifetime version

  • Selected Abstracts


    Obsessive-compulsive disorder among African Americans and blacks of Caribbean descent: results from the national survey of American life,

    DEPRESSION AND ANXIETY, Issue 12 2008
    Joseph A. Himle Ph.D.
    Abstract Background: There is limited research regarding the nature and prevalence of obsessive-compulsive disorder (OCD) among various racial and ethnic subpopulations within the United States, including African Americans and blacks of Caribbean descent. Although heterogeneity within the black population in the United States has largely been ignored, notable differences exist between blacks of Caribbean descent and African Americans with respect to ethnicity, national heritage, and living circumstances. This is the first comprehensive examination of OCD among African Americans and blacks of Caribbean descent. Methods: Data from the National Survey of American Life, a national household probability sample of African Americans and Caribbean blacks in the United States, were used to examine rates of OCD among these groups. Results: Lifetime and 12-month OCD prevalence estimates were very similar for African Americans and Caribbean blacks. Persistence of OCD and rates of co-occurring psychiatric disorders were very high and also similar between African American and Caribbean black respondents. Both groups had high levels of overall mental illness severity and functional impairment. Use of services was low for both groups, particularly in specialty mental health settings. Use of anti-obsessional medications was also rare, especially among the Caribbean black OCD population. Conclusions: OCD among African Americans and Caribbean blacks is very persistent, often accompanied by other psychiatric disorders, and is associated with high overall mental illness severity and functional impairment. It is also likely that very few blacks in the United States with OCD are receiving evidence-based treatment and thus considerable effort is needed to bring treatment to these groups. Depression and Anxiety, 2008. Published 2008 Wiley-Liss, Inc. [source]


    Re: Botox for a Lifetime or Tumescent Axillary Liposuction and Curettage: Once

    DERMATOLOGIC SURGERY, Issue 7 2003
    Article first published online: 29 AUG 200
    No abstract is available for this article. [source]


    Designing a Stable Cathode with Multiple Layers to Improve the Operational Lifetime of Polymer Light-Emitting Diodes

    ADVANCED FUNCTIONAL MATERIALS, Issue 12 2009
    Tae-Woo Lee
    Abstract The short device lifetime of blue polymer light-emitting diodes (PLEDs) is still a bottleneck for commercialization of self-emissive full-color displays. Since the cathode in the device has a dominant influence on the device lifetime, a systematic design of the cathode structure is necessary. The operational lifetime of blue PLEDs can be greatly improved by introducing a three-layer (BaF2/Ca/Al) cathode compared with conventional two-layer cathodes (BaF2/Al and Ba/Al). Therefore, the roles of the BaF2 and Ca layers in terms of electron injection, luminous efficiency, and device lifetime are here investigated. For efficient electron injection, the BaF2 layer should be deposited to the thickness of at least one monolayer (,3,nm). However, it is found that the device lifetime does not show a strong relation with the electron injection or luminous efficiency. In order to prolong the device lifetime, sufficient reaction between BaF2 and the overlying Ca layer should take place during the deposition where the thickness of each layer is around that of a monolayer. [source]


    Modulation of the Lifetime of Water Bound to Lanthanide Metal Ions in Complexes with Ligands Derived from 1,4,7,10-Tetraazacyclododecane Tetraacetate (DOTA)

    HELVETICA CHIMICA ACTA, Issue 5 2005
    Shanrong Zhang
    A series of di- and tetraamide derivatives of DOTA were synthesized, and their lanthanide(III) complexes were examined by multinuclear 1H-, 13C-, and 17O-NMR spectroscopy, and compared with literature data of similar, known complexes (Table). All ligands formed structures similar to the parent [LnIII(DOTA)], complexes, with four N-atoms and four O-atoms from DOTA and one O-atom from the inner-sphere water molecules. Interestingly, the lifetimes ,M of the inner-sphere, metal-bound water molecules vary widely, ranging from nano- to milliseconds, depending on the identity of the pendent amide side chains. In general, positively charged [LnIII(DOTA-tetraamide)]3+ complexes display the longest residence times (high ,M values), while complexes with additional charged functional groups on the extended amides display much smaller ,M values, even when the side groups are not directly coordinated to the central Ln3+ ions. The design of novel [LnIII(DOTA-tetraamide)]3+ complexes with a wide, tunable range of ,M values is of prime importance for the application of fast-responding, paramagnetic chemical-exchange-saturation-transfer (PARACEST) imaging agents used for the study of physiological and metabolic processes. [source]


    Extended Lifetime of Organic Field-Effect Transistors Encapsulated with Titanium Sub-Oxide as an ,Active' Passivation/Barrier Layer

    ADVANCED MATERIALS, Issue 19 2009
    Shinuk Cho
    A thin capping layer of titanium sub-oxide (TiOx) prepared by sol,gel synthesis from titanium alkoxides extends the lifetime of organic FETs. The TiOx layer functions as an ,active' passivation/barrier layer that actually removes oxygen and water vapor from the organic semiconductor. The results demonstrate a significant improvement in the lifetime of organic field-effect transistors when exposed to air. [source]


    Lifetime and baseline alcohol intake and risk of cancer of the upper aero-digestive tract in the European Prospective Investigation into Cancer and Nutrition (EPIC) study

    INTERNATIONAL JOURNAL OF CANCER, Issue 2 2009
    Cornelia Weikert
    Abstract Recent alcohol consumption is an established risk factor for squamous cell carcinoma (SCC) of the upper aero-digestive tract. In contrast, the role of lifetime exposure to alcohol with regard to risk of SCC is not well established. Historical data on alcohol use are available in 271,253 participants of the European Prospective Investigation into Cancer and Nutrition (EPIC). During 2,330,381 person years, 392 incident SCC cases (279 men and 113 women) were identified. Cox regression was applied to model sex-specific associations between lifetime alcohol intake and SCC risk adjusting for potential confounders including smoking. Compared to men who drank 0.1,6.0 g/day alcohol at lifetime, the relative risks (RR) for developing SCC were significantly increased for men who drank 30.1,60.0 g/day (RR 1.65, 95% confidence interval:1.00,2.71), 60.1,96.0 g/day (RR 2.20, 95%CI 1.23,3.95), and >96.0 g/day, (RR 4.63, 95% CI 2.52,8.48), and for former drinkers (RR 4.14, 95%CI 2.38,7.19). These risk estimates did not considerably change when baseline alcohol intake was analyzed. Compared to women who drank 0.1,6.0 g/day alcohol intake at lifetime, the RR were significantly increased for women who drank >30 g/d (RR 6.05, 95%CI 2.98,12.3). Applying similar categories, the relative risk for baseline alcohol intake was 3.26 (95%CI 1.82,5.87). We observed a stronger association between alcohol intake at lifetime and risk of SCC in women compared to men (p for interaction = 0.045). The strong dose-response relation for lifetime alcohol use underscores that alcohol is an important risk factor of SCC of the upper aero-digestive tract throughout life. © 2009 UICC [source]


    Should bulimia nervosa be subtyped by historyof anorexia nervosa?

    INTERNATIONAL JOURNAL OF EATING DISORDERS, Issue S3 2007
    A longitudinal validation
    Abstract Objective: To determine whether a past diagnosis of anorexia nervosa (AN) predicts longitudinal course and outcome among women with bulimia nervosa (BN). Method: A subset (n = 176) of participants in the Longitudinal Study of Anorexia and Bulimia Nervosa who met DSM-IV criteria for BN either at study intake (n = 144) or during follow-up (n = 32; 4 had restricting AN at intake, 28 had binge/purge AN at intake) were included in this report. Over a median of 9 years, weekly eating disorder symptom data were collected from participants using the Longitudinal Interview Follow-up Examination, Eating Disorders Version. Results: While there were no between-group differences in likelihood of partial recovery, women with BN who had a history of AN were more likely to have a protracted illness, relapsing into AN during follow-up, compared to those with no AN history who were more likely to move from partial to full recovery. Conclusion: Lifetime AN is an important prognostic indicator among women with BN and these longitudinal data would support the subtyping of BN on the basis of AN history. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007 [source]


    Prenatal Care: The Beginning of a Lifetime

    JOURNAL OF OBSTETRIC, GYNECOLOGIC & NEONATAL NURSING, Issue 2010
    Childbearing
    No abstract is available for this article. [source]


    Psychiatric Comorbidity in Long-Term Abstinent Alcoholic Individuals

    ALCOHOLISM, Issue 5 2007
    Victoria Di Sclafani
    Background: A high prevalence of comorbid psychiatric disorders has been demonstrated in individuals with an alcohol use disorder in both community and treatment samples, with higher comorbidity in treatment samples. In this study, we examined lifetime and current psychiatric diagnoses in long-term abstinent alcoholic individuals (LTAA; mean abstinence=6.3 years; n=52) compared with age and gender-comparable non-alcoholic controls (NC; n=48). We asked the following questions: (1) to achieve long-term abstinence, must an individual be relatively psychiatrically healthy (i.e., comparable with NC) and (2) can ongoing abstinence be maintained in the face of a current psychiatric disorder? Methods: Lifetime and current (prior 12 months) psychiatric diagnoses were assessed in the mood, anxiety, and externalizing disorder domains using the computerized Diagnostic Interview Schedule (c-DIS). Results: Over 85% of LTAA had a lifetime psychiatric diagnosis, compared with 50% of NC. Long-term abstinent alcoholic individuals had a higher prevalence than NC of lifetime mood, anxiety, and externalizing disorder diagnoses. Long-term abstinent alcoholic individuals also had a greater prevalence than NC of current mood and anxiety diagnoses. Although LTAA had a greater lifetime prevalence of an antisocial personality disorder (ASPD) than NC, no LTAA or NC had a current ASPD diagnosis. Finally, there was no association of duration of abstinence with lifetime or current psychiatric diagnoses, consistent with psychiatric diagnoses having little effect on relapse. Conclusions: Our results suggest that: (1) the presence of a lifetime psychiatric diagnosis does not militate against achieving long-term abstinence, (2) abstinence can be maintained in the presence of a current mood or anxiety disorder, and (3) a current diagnosis of ASPD may not be compatible with long-term abstinence. The relatively low levels of antisocial behavior compared with preabstinence (as indicated by no LTAA meeting current criteria for ASPD) raises the question of whether the neurobiology underlying antisocial behavior is changed in abstinence, or brought under increased executive control, or both. [source]


    Flexibility in Proteins: Tuning the Sensitivity to O2 Diffusion by Varying the Lifetime of a Phosphorescent Sensor in Horseradish Peroxidase,

    PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2004
    Janna Nibbs
    ABSTRACT The heme in horseradish peroxidase (HRP) was replaced by phosphorescent Pt-mesoporphyrin IX (PtMP), which acted as a phosphorescent marker of oxygen quenching and allowed comparison with another probe, Pd-mesoporphyrin IX (Khajehpour et al. (2003) Proteins 53, 656,666). Benzohydroxamic acid (BHA), a competitive inhibitor of the enzyme, was also used to monitor its effects on phosphorescence quenching. With the addition of BHA, in the presence of oxygen, the phosphorescence intensity of the protein increased. In contrast, the addition of BHA, in the absence of oxygen, reduced the phosphorescence intensity of the protein. Kd= 18 ,M when BHA binds to PtMP-HRP. The effect of BHA can be explained by two factors: (1) BHA reduces the accessibility of O2 to the protein interior and (2) BHA itself quenches the phosphorescence. Consistent with this, the oxygen quenching of the phosphorescence of PtMP-HRP gave a quenching constant of kq= 234 mm Hg,1 s,1 in the absence of BHA and kq= 28.7 mm Hg,1 s,1 in the presence of BHA. The quenching rate of BHA is 4000 s,1. The relative quantum yield of the phosphorescence of the Pt derivative is about six times that of the Pd derivative, whereas the phosphorescence lifetime is approximately eight times shorter. The high quantum yield and suitable lifetime make Pt-porphyrins appropriate as sensors of O2 diffusion and flexibility in heme proteins. [source]


    InGaN-based 518 and 488,nm laser diodes on c -plane GaN substrate

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2010
    Takashi Miyoshi
    Abstract We succeeded in fabricating InGaN-based laser diodes (LDs) with a wavelength of 518 and 488,nm under continuous wave (cw) operation. The both LDs structures were grown on conventional c -plane GaN substrates by metal organic chemical vapor deposition (MOCVD). The threshold current and threshold voltage were 45,mA and 5.5,V at 518,nm, 30,mA and 4.5,V at 488,nm, respectively. The lifetime test of these LDs was carried out under high driving temperature up to 80,°C in cw operation. Lifetime was estimated to be over 5000,h with an optical output power of 5,mW at 80,°C in 515,518,nm LDs from 1000,h operation, and was estimated to be over 10,000,h with an output power of 60,mW at 60,°C in 488,nm LDs from 2000,h operation. [source]


    Lifetime and 12-Month Intermittent Explosive Disorder in Latinos

    AMERICAN JOURNAL OF ORTHOPSYCHIATRY, Issue 1 2008
    Alexander N. Ortega PhD
    This study examined the occurrence, correlates, and psychiatric co-morbidities of lifetime and 12-month intermittent explosive disorder (IED) and whether impairment due to IED differed across Latino groups. We used data on 2,554 Latino adults (75.5% response rate) from the National Latino and Asian American Study (NLAAS). Lifetime and 12-month prevalence of IED among Latinos were 5.8% and 4.1%, respectively. Unemployment was a common risk factor for both lifetime and 12-month IED. Protective factors for both lifetime and 12-month IED were having poor/fair English proficiency and being born outside the U.S. mainland. Cubans, Mexicans and other Latinos had lower odds of both lifetime and 12-month IED relative to Puerto Ricans, while Puerto Ricans with IED did not demonstrate worse impairment compared with the other groups with IED. Lifetime and 12-month IED were associated with several depressive, anxiety, and substance use disorders. Given its significant association with a wide-range of mental disorders, future research should consider the validity of IED as a unique disorder or whether it is merely a constellation of symptoms that accompanies a variety of mental diseases. [source]


    On the Effectiveness of the Lifetime,Employment,Contract Policy

    THE MANCHESTER SCHOOL, Issue 6 2002
    Kazuhiro Ohnishi
    This paper examines a subgame perfect equilibrium when one of two duopolists executes a lifetime,employment,contract policy, which is a strategic commitment that generates kinks in the reaction curve, by using a two,stage quantity,setting model. The purpose of the paper is to show concretely in what kinds of cases the policy is effective. [source]


    Selective Capture of Water Using Microporous Adsorbents To Increase the Lifetime of Lubricants

    CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 3 2009
    Eng-Poh Ng
    Abstract Long live lubricants: The selective capture of water from lubricants using nanosized microporous aluminophosphate (AEI) and aluminosilicate materials was studied. Nearly 98,% of the moisture was removed from the lubricating oil under ambient conditions, resulting in a significant improvement in the lubricating service lifetime. Moreover, both the lubricant and the microporous sorbents can be recovered and reused. The selective capture of water from lubricants using nanosized microporous aluminophosphate and aluminosilicate materials was studied with an aim to increase the lifetime of the lubricating mineral oil. The amount of water present in oxidized lubricating oil before and after treatment with microporous materials was studied by FTIR spectroscopy and determined quantitatively using the Karl Fischer titration method. Nanosized aluminophosphate revealed a high selectivity for water without adsorbing other additives, in contrast to nanosized aluminosilicates which also adsorb polar oxidation products and ionic additives. About 98,% of the initial moisture could be removed from the lubricating oil under ambient conditions, resulting in a significant improvement in the lubricating service lifetime. Moreover, no by-products are formed during the process and both the lubricant and the sorbents can be recovered and reused, thus the method is environmentally friendly. [source]


    ,-Carbonyl Substituent Effect on the Lifetimes of Triplet 1,4-Biradicals from Norrish-Type-II Reactions

    CHEMISTRY - A EUROPEAN JOURNAL, Issue 17 2006
    Xichen Cai Dr.
    Abstract Triplet 1,4-biradicals were generated by Norrish-Type-II hydrogen transfer from ,-heteroatom-substituted ,-branched butyrophenones 1,6 and detected by laser flash absorption measurements. For three oxy-substituted compounds 2,4 (R,=OH, OCOMe, OCOOEt) comparable lifetimes were determined in acetonitrile (roughly 1.5 ,s). In benzene, divergent trends were observed: for the hydroxy compound 2 a lower lifetime of 790 ns was determined, whereas for 3 and 4 the lifetimes increased to 4.9 ,s. Photolyses of the ,-amino-substituted compounds 1 and 6 resulted in transient species with significant lower lifetimes (for 1 160 ns in benzene and 450 ns in acetonitrile; for 6 <100 ns in both solvents). The mesyloxy substrate 5 undergoes rapid CO bond cleavage upon photolysis and no transient triplet species were detected. Computational (UB3,LYP/6,31G* and natural don orbital (NBO) analyses) results supported the assumption of a negative hyperconjugative interaction strongly stabilizing ,-oxy-substituted over ,-amino-substituted radicals. [source]


    The Effect of Platinum on Diffusion Kinetics in ,-NiAl: Implications for Thermal Barrier Coating Lifetimes

    CHEMPHYSCHEM, Issue 14 2009
    Kristen A. Marino
    No abstract is available for this article. [source]


    Positron Annihilation Lifetimes in Cucurbiturils: Evidence of Internal Inclusion of Gold in CB[7]

    CHEMPHYSCHEM, Issue 5 2009
    Pedro Montes-Navajas
    Abstract Positron lifetime spectroscopy serves to determine the void volumes of cucurbituril (CB) capsules, which are not amenable to standard gas adsorption methods. In the case of the host,guest complex Au§CB[7], it also provides evidence of the inclusion of gold nanoparticles in the CB cavity (see space-filling model; Au golden, C gray, H cyan, N blue, O red). Positron annihilation lifetime (PAL) measurements are carried out to determine the cavity dimensions of hydrated and dehydrated cucurbiturils (CB[n]; n=5,6,7,8). In the case of hydrated samples, the dimensions of the cavity are unrelated to the number of glycoluril units of the CB, whereas for dehydrated samples the cavity dimensions measured by PAL follow the expected order, although the experimental values obtained by PAL are significantly smaller than the dimensions of each CB determined by crystallography. For a host,guest complex in which colloidal gold nanoparticles are assumed to be included inside CB[7], a significant reduction of the cavity size is measured. This represents an experimental evidence of the inclusion of gold inside CB[7], which complements previous high-resolution transmission electron microscopy (TEM) images. [source]


    Competence Models and the Maintenance Problem

    COMPUTATIONAL INTELLIGENCE, Issue 2 2001
    Barry Smyth
    Case-based reasoning (CBR) systems solve problems by retrieving and adapting the solutions to similar problems that have been stored previously as a case base of individual problem solving episodes or cases. The maintenance problem refers to the problem of how to optimize the performance of a CBR system during its operational lifetime. It can have a significant impact on all the knowledge sources associated with a system (the case base, the similarity knowledge, the adaptation knowledge, etc.), and over time, any one, or more, of these knowledge sources may need to be adapted to better fit the current problem-solving environment. For example, many maintenance solutions focus on the maintenance of case knowledge by adding, deleting, or editing cases. This has lead to a renewed interest in the issue of case competence, since many maintenance solutions must ensure that system competence is not adversely affected by the maintenance process. In fact, we argue that ultimately any generic maintenance solution must explicitly incorporate competence factors into its maintenance policies. For this reason, in our work we have focused on developing explanatory and predictive models of case competence that can provide a sound foundation for future maintenance solutions. In this article we provide a comprehensive survey of this research, and we show how these models have been used to develop a number of innovative and successful maintenance solutions to a variety of different maintenance problems. [source]


    Spins as probes of different electronic states

    CONCEPTS IN MAGNETIC RESONANCE, Issue 2 2007
    Dieter Suter
    Abstract Nuclear spins are efficient probes of electronic states. Because most NMR experiments are performed in thermal equilibrium, they probe the electronic ground state,the only state that is significantly populated under ambient conditions. Probing electronically excited states becomes possible, if magnetic resonance techniques are combined with optical (laser) excitation. Depending on the nature of the electronic state, drastic changes of the magnetic resonance parameters may be observed. We discuss the basic principles of this type of investigation. Depending on the lifetime of the electronically excited state, it is possible to measure separate spectra of ground and excited state if the lifetime is long on the NMR timescale, or an averaged spectrum if the lifetime is short. We present examples for both limiting cases using rare earth ions and semiconductor heterostructures. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 116,126, 2007. [source]


    Performance analysis and improvement for BitTorrent-like file sharing systems

    CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 13 2007
    Ye Tian
    Abstract In this paper, we present a simple mathematical model for studying the performance of the BitTorrent (http://www.bittorrent.com) file sharing system. We are especially interested in the distribution of peers in different states of the download job progress. With the model we find that the distribution of the download peers follows an asymmetric U-shaped curve under the stable state, due to BitTorrent's unchoking strategies. In addition, we find that the seeds' departure rate and the download peers' abort rate will influence the peer distribution in different ways notably. We also analyze the content availability under the dying process of the BitTorrent file sharing system. We find that the system's stability deteriorates with decreasing and unevenly distributed online peers, and BitTorrent's built-in ,tit-for-tat' unchoking strategy could not help to preserve the integrity of the file among the download peers. We propose an innovative ,tit-for-tat' unchoking strategy which enables more peers to finish the download job and prolongs the system's lifetime. By playing our innovative strategy, download peers could cooperate to improve the stability of the system by making a trade-off between the current downloading rate and the future service availability. Finally, experimental results are presented to validate our analytical results and support our proposals. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Effect of redundancy on the mean time to failure of wireless sensor networks

    CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 8 2007
    Anh Phan Speer
    Abstract In data-driven wireless sensor networks (WSNs), the system must perform data sensing and retrieval and possibly aggregate data as a response at runtime. As a WSN is often deployed unattended in areas where replacements of failed sensors are difficult, energy conservation is of primary concern. While the use of redundancy is desirable in terms of satisfying user queries to cope with sensor and transmission faults, it may adversely shorten the lifetime of the WSN, as more sensor nodes will have to be used to answer queries, causing the energy of the system to drain quickly. In this paper, we analyze the effect of redundancy on the mean time to failure (MTTF) of a WSN in terms of the number of queries the system is able to answer correctly before it fails due to either sensor/transmission faults or energy depletion. In particular, we analyze the effect of redundancy on the MTTF of cluster-structured WSNs for energy conservations. We show that a tradeoff exists between redundancy and MTTF. Furthermore, an optimal redundancy level exists such that the MTTF of the system is maximized. Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Fluorescence lifetime imaging of activatable target specific molecular probes

    CONTRAST MEDIA & MOLECULAR IMAGING, Issue 1 2010
    Raphael Alford
    Abstract In vivo optical imaging using fluorescently labeled self-quenched monoclonal antibodies, activated through binding and internalization within target cells, results in excellent target-to-background ratios. We hypothesized that these molecular probes could be utilized to accurately report on cellular internalization with fluorescence lifetime imaging (FLI). Two imaging probes were synthesized, consisting of the antibody trastuzumab (targeting HER2/neu) conjugated to Alexa Fluor750 in ratios of either 1:8 or 1:1. Fluorescence intensity and lifetime of each conjugate were initially determined at endosomal pHs. Since the 1:8 conjugate is self-quenched, the fluorescence lifetime of each probe was also determined after exposure to the known dequencher SDS. In vitro imaging experiments were performed using 3T3/HER2+ and BALB/3T3 (HER2,) cell lines. Changes in fluorescence lifetime correlated with temperature- and time-dependent cellular internalization. In vivo imaging studies in mice with dual flank tumors [3T3/HER2+ and BALB/3T3 (HER2,)] detected a minimal difference in FLI. In conclusion, fluorescence lifetime imaging monitors the internalization of target-specific activatable antibody,fluorophore conjugates in vitro. Challenges remain in adapting this methodology to in vivo imaging. Copyright © 2010 John Wiley & Sons, Ltd. [source]


    Molecular recognition of sugars by lanthanide (III) complexes of a conjugate of N, N -bis[2-[bis[2-(1, 1-dimethylethoxy)-2-oxoethyl]amino]ethyl]glycine and phenylboronic acid

    CONTRAST MEDIA & MOLECULAR IMAGING, Issue 4 2007
    Elisa Battistini
    Abstract A novel conjugate of phenylboronic acid and an Ln(DTPA) derivative, in which the central acetate pendant arm was replaced by the methylamide of L -lysine, was synthesized and characterized. The results of a fit of variable 17O NMR data and a 1H NMRD profile show that the water residence lifetime of the Gd(III) complex (150,ns) is shorter than that of the parent compound Gd(DTPA)2, (303,ns). Furthermore, the data suggest that several water molecules in the second coordination sphere of Gd(III) contribute to the relaxivity of the conjugate. The Ln(III) complexes of this conjugate are highly suitable for molecular recognition of sugars. The interaction with various sugars was investigated by 11B NMR spectroscopy. Thanks to the thiourea function that links the phenylboronic acid targeting vector with the DTPA derivative, the interactions are stronger than that of phenylboronic acid itself. In particular, the interaction with N -propylfructosamine, a model for the glucose residue in glycated human serum albumin (HSA), is very strong. Unfortunately, the complex also shows a rather strong interaction with hexose-free HSA (KA,=,705,±,300). Copyright © 2007 John Wiley & Sons, Ltd. [source]


    Photoelectrical properties of crystalline titanium dioxide thin films after thermo-annealing

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 5 2007
    R. Sathyamoorthy
    Abstract This paper reports the photoelectrical properties of sol gel derived titanium dioxide (TiO2) thin films annealed at different temperatures (425-900°C). The structure of the as-grown film was found to be amorphous and it transforms to crystalline upon annealing. The trap levels are studied by thermally stimulated current (TSC) measurements. A single trap level with activation energy of 1.5 eV was identified. The steady state and transient photocurrent was measured and the results are discussed on the basis of structural transformation. The photocurrent was found to be maximum for the films annealed at 425°C and further it decreases with annealing at higher temperatures. The photoconduction parameters such as carrier lifetime, lifetime decay constant and photosensitivity were calculated and the results are discussed as a function of annealing temperature. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


    Studies on the growth and optical characterization of dysprosium gadolinium oxalate single crystals

    CRYSTAL RESEARCH AND TECHNOLOGY, Issue 2 2004
    A. Elizebeth
    Abstract Preparation and optical characterization of dysprosium gadolinium oxalate (DGO) single crystal is reported. The crystals were grown using silica gel technique, by the controlled reaction of rare earth nitrates with oxalic acid. Crystals were characterized using X-ray powder diffraction, optical absorption and fluorescence studies. Radiative transition probability, fluorescence branching ratio and radiative lifetime of Dy3+ in the crystal are evaluated by the parameterization of the absorption spectrum by the Judd-Ofelt theory. The recorded fluorescence spectrum showed two well resolved peaks at 480 nm and 571 nm and are assigned to the transitions from 4F9/2 , 6H15/2 and 6H13/2 of Dy3+. Stimulated emission crossection and optical gain of these transitions are also evaluated. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


    Genetics of anxiety disorders: the complex road from DSM to DNA,

    DEPRESSION AND ANXIETY, Issue 11 2009
    Jordan W. Smoller M.D. Sc.D.
    Abstract Anxiety disorders are among the most common psychiatric disorders, affecting one in four individuals over a lifetime. Although our understanding of the etiology of these disorders is incomplete, familial and genetic factors are established risk factors. However, identifying the specific casual genes has been difficult. Within the past several years, advances in molecular and statistical genetic methods have made the genetic dissection of complex disorders a feasible project. Here we provide an overview of these developments, with a focus on their implications for genetic studies of anxiety disorders. Although the genetic and phenotypic complexity of the anxiety disorders present formidable challenges, advances in neuroimaging and experimental animal models of anxiety and fear offer important opportunities for discovery. Real progress in identifying the genetic basis of anxiety disorders will require integrative approaches that make use of these biologic tools as well as larger-scale genomic studies. If successful, such efforts may yield novel and more effective approaches for the prevention and treatment of these common and costly disorders. Depression and Anxiety, 2009. © 2009 Wiley-Liss, Inc. [source]


    An open-label trial of enhanced brief interpersonal psychotherapy in depressed mothers whose children are receiving psychiatric treatment,,

    DEPRESSION AND ANXIETY, Issue 7 2006
    Holly A. Swartz M.D.
    Abstract Major depression affects one out of five women during her lifetime. Depressed mothers with psychiatrically ill children represent an especially vulnerable population. Challenged by the demands of caring for ill children, these mothers often put their own needs last; consequently, their depressions remain untreated. This population is especially difficult to engage in treatment. We have developed a nine-session intervention, an engagement session followed by eight sessions of brief interpersonal psychotherapy designed to increase maternal participation in their own psychotherapy, resolve symptoms of maternal depression, and enhance relationships (IPT-MOMS). This open-label trial assesses the feasibility and acceptability of providing this treatment to depressed mothers. Thirteen mothers meeting DSM-IV criteria for major depression were recruited from a pediatric mental health clinic where their school-age children were receiving psychiatric treatment. Subjects (mothers) were treated openly with IPT-MOMS. Eighty-five percent (11/13) completed the study. Subjects were evaluated with the Hamilton Rating Scale for Depression, and completed self-report measures of quality of life and functioning at three time points: baseline, after treatment completion, and 6-months posttreatment. A signed rank test was used to compare measurement changes between assessment time points. Subjects showed significant improvement from baseline to posttreatment on measures of maternal symptoms and functioning. These gains were maintained at 6-month follow-up. Therapy was well tolerated and accepted by depressed mothers, who are typically difficult to engage in treatment. A high proportion of subjects completed treatment and experienced improvements in functioning. Future randomized clinical trials are needed to establish the efficacy of this approach. Depression and Anxiety 23:398,404, 2006. Published 2006 Wiley-Liss, Inc. [source]


    Panic and suicidal ideation and suicide attempts: results from the National Comorbidity Survey

    DEPRESSION AND ANXIETY, Issue 3 2006
    M.P.H., Renee D. Goodwin Ph.D.
    Abstract Our objective was to determine the association between panic attacks (PAs) and panic disorder (PD), and suicidal ideation (SI) and suicide attempts (SAs) in a nationally representative sample of adults in the community. Data were drawn from the National Comorbidity Survey (n=5,877), a representative household sample of adults ages 15,54 in the United States. Multiple logistic regression analyses were used to examine the relationship between current and lifetime PA and PD and SI and SA, adjusting for differences in demographic characteristics, comorbid mental disorders (major depression, alcohol dependence, and substance dependence), childhood trauma (physical and sexual abuse), and number of lifetime mental disorders. Past-year and lifetime PA and PD were associated with increased SI (both past year and lifetime), and persisted after adjusting for comorbidity and early trauma. Associations between PA and SA were no longer statistically significant after adjusting for comorbidity. Past-year and lifetime PD were associated with lifetime SA, but these associations were no longer statistically significant after adjusting for comorbidity. Past-year and lifetime PD were associated with past-year SA, and this association persisted after adjusting for demographics, comorbidity, and number of lifetime mental disorders. These findings are consistent with previous results, and further help to clarify the relationships between panic and suicide behavior by identifying potential methodological reasons for inconsistencies in results from previous studies. Depression and Anxiety 23:124,132, 2006. © 2006 Wiley-Liss, Inc. [source]


    Cosmetics and contact dermatitis

    DERMATOLOGIC THERAPY, Issue 3 2001
    Ronni Wolf
    Modern cosmetic and skin care products are safe for most users and adverse reactions to them are very rare considering the number of people in contact with numerous products over a lifetime of use. Improvements in safety, tolerance, and skin compatibility will not prevent cosmetic product side effects from increasing in the future because of the continuing goals of intensifying their biological activity and therapeutic efficacy. Therefore, now more than ever, dermatologists should be familiar with all possible untoward reactions to cosmetics. Adverse reactions include an extreme variant of sensitive skin, called "cosmetic intolerance syndrome," describing individuals who are no longer able to tolerate a wide range of cosmetic products. "True" allergic reactions to cosmetics occur much less commonly than irritant reactions. These are of great importance to the dermatologist because they are more serious, more difficult to treat, and require absolute abstention from the causative agent. Eczematous, damaged skin is especially prone to develop allergies. [source]


    Patient-centred and professional-directed implementation strategies for diabetes guidelines: a cluster-randomized trial-based cost-effectiveness analysis

    DIABETIC MEDICINE, Issue 2 2006
    R. F. Dijkstra
    Abstract Aims Economic evaluations of diabetes interventions do not usually include analyses on effects and cost of implementation strategies. This leads to optimistic cost-effectiveness estimates. This study reports empirical findings on the cost-effectiveness of two implementation strategies compared with usual hospital outpatient care. It includes both patient-related and intervention-related cost. Patients and methods In a clustered-randomized controlled trial design, 13 Dutch general hospitals were randomly assigned to a control group, a professional-directed or a patient-centred implementation programme. Professionals received feedback on baseline data, education and reminders. Patients in the patient-centred group received education and diabetes passports. A validated probabilistic Dutch diabetes model and the UKPDS risk engine are used to compute lifetime disease outcomes and cost in the three groups, including uncertainties. Results Glycated haemoglobin (HbA1c) at 1 year (the measure used to predict diabetes outcome changes over a lifetime) decreased by 0.2% in the professional-change group and by 0.3% in the patient-centred group, while it increased by 0.2% in the control group. Costs of primary implementation were < 5 Euro per head in both groups, but average lifetime costs of improved care and longer life expectancy rose by 9389 Euro and 9620 Euro, respectively. Life expectancy improved by 0.34 and 0.63 years, and quality-adjusted life years (QALY) by 0.29 and 0.59. Accordingly, the incremental cost per QALY was 32 218 Euro for professional-change care and 16 353 for patient-centred care compared with control, and 881 Euro for patient-centred vs. professional-change care. Uncertainties are presented in acceptability curves: above 65 Euro per annum the patient-directed strategy is most likely the optimum choice. Conclusion Both guideline implementation strategies in secondary care are cost-effective compared with current care, by Dutch standards, for these patients. Additional annual costs per patient using patient passports are low. This analysis supports patient involvement in diabetes in the Netherlands, and probably also in other Western European settings. [source]