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Central Point (central + point)
Selected AbstractsCell division in magnetotactic bacteria splits magnetosome chain in halfJOURNAL OF BASIC MICROBIOLOGY, Issue 4 2010Sarah S. Staniland Abstract Cell division in magnetotactic bacteria has attracted much interest, speculation and hypothesis with respect to the biomineralised chains of magnetic iron-oxide particles known as magnetosomes. Here we report direct Transmission Electron Microscopy (TEM) evidence that division occurs at a central point of the cell and the chain, cleaving the magnetosome chain in two. Additionally, the new magnetosome chain relocates rapidly to the centre of the daughter cell and the number of magnetosomes is directly proportional to the cell length, even during the division part of the cell cycle. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Genetic dissection of the role of ethylene in regulating auxin-dependent lateral and adventitious root formation in tomatoTHE PLANT JOURNAL, Issue 1 2010Sangeeta Negi Summary In this study we investigated the role of ethylene in the formation of lateral and adventitious roots in tomato (Solanum lycopersicum) using mutants isolated for altered ethylene signaling and fruit ripening. Mutations that block ethylene responses and delay ripening ,Nr (Never ripe), gr (green ripe), nor (non ripening), and rin (ripening inhibitor) , have enhanced lateral root formation. In contrast, the epi (epinastic) mutant, which has elevated ethylene and constitutive ethylene signaling in some tissues, or treatment with the ethylene precursor 1-aminocyclopropane carboxylic acid (ACC), reduces lateral root formation. Treatment with ACC inhibits the initiation and elongation of lateral roots, except in the Nr genotype. Root basipetal and acropetal indole-3-acetic acid (IAA) transport increase with ACC treatments or in the epi mutant, while in the Nr mutant there is less auxin transport than in the wild type and transport is insensitive to ACC. In contrast, the process of adventitious root formation shows the opposite response to ethylene, with ACC treatment and the epi mutation increasing adventitious root formation and the Nr mutation reducing the number of adventitious roots. In hypocotyls, ACC treatment negatively regulated IAA transport while the Nr mutant showed increased IAA transport in hypocotyls. Ethylene significantly reduces free IAA content in roots, but only subtly changes free IAA content in tomato hypocotyls. These results indicate a negative role for ethylene in lateral root formation and a positive role in adventitious root formation with modulation of auxin transport as a central point of ethylene,auxin crosstalk. [source] Effect of an Integrated Public Health Curriculum in an Emergency Medicine ResidencyACADEMIC EMERGENCY MEDICINE, Issue 2009Marian Betz Background: Emergency departments (EDs) serve as a central point of interaction between the public and the medical system. Emergency physicians need education in public health in order to optimize their clinical care and their ability to evaluate potential public health interventions in the ED. Methods: As part of the Centers for Disease Control and Prevention (CDC) and the Association of American Medical College's (AAMC) national initiative for "Regional Medicine-Public Health Education Centers-Graduate Medical Education", we designed and implemented a new public health curriculum for the emergency medicine residents. Over four sessions during regular didactic time, we used a modular approach to link a basic public health principle, such as environmental hazard assessment, to a relevant clinical topic, such as violent patients and ED safety. Each session emphasized resident involvement, including small group work and role-plays. Journal clubs and quality assurance projects supplemented the curriculum. We sought resident feedback through focus groups and anonymous online pre- and post-tests for each session. Assessment: Both before and after the curriculum, 76% of responders felt it was important for physicians to receive training in public health. The program appeared to have a positive effect on residents' comfort level with various public health topics, and felt the residency program had taught them the skills necessary to implement public health principles in clinical practice (23.8%, versus 11.5% before; p<0.05). Conclusions: Integration of public health principles into existing clinical curricula in emergency medicine may increase resident interest and knowledge. Combining public health and emergency medicine topics in regular didactic conferences facilitates public health education for residents. [source] Statistical density modification using local pattern matchingACTA CRYSTALLOGRAPHICA SECTION D, Issue 10 2003Thomas C. Terwilliger A method for improving crystallographic phases is presented that is based on the preferential occurrence of certain local patterns of electron density in macromolecular electron-density maps. The method focuses on the relationship between the value of electron density at a point in the map and the pattern of density surrounding this point. Patterns of density that can be superimposed by rotation about the central point are considered equivalent. Standard templates are created from experimental or model electron-density maps by clustering and averaging local patterns of electron density. The clustering is based on correlation coefficients after rotation to maximize the correlation. Experimental or model maps are also used to create histograms relating the value of electron density at the central point to the correlation coefficient of the density surrounding this point with each member of the set of standard patterns. These histograms are then used to estimate the electron density at each point in a new experimental electron-density map using the pattern of electron density at points surrounding that point and the correlation coefficient of this density to each of the set of standard templates, again after rotation to maximize the correlation. The method is strengthened by excluding any information from the point in question from both the templates and the local pattern of density in the calculation. A function based on the origin of the Patterson function is used to remove information about the electron density at the point in question from nearby electron density. This allows an estimation of the electron density at each point in a map, using only information from other points in the process. The resulting estimates of electron density are shown to have errors that are nearly independent of the errors in the original map using model data and templates calculated at a resolution of 2.6,Ĺ. Owing to this independence of errors, information from the new map can be combined in a simple fashion with information from the original map to create an improved map. An iterative phase-improvement process using this approach and other applications of the image-reconstruction method are described and applied to experimental data at resolutions ranging from 2.4 to 2.8,Ĺ. [source] Characterization of the anatomical extension pattern of localized prostate cancer arising in the peripheral zoneBJU INTERNATIONAL, Issue 11 2010Mototsugu Muramaki Study Type , Diagnostic (non-consecutive series) Level of Evidence 3b OBJECTIVES To characterize the anatomical extension pattern of prostate cancer arising in the peripheral zone (PZ) in radical prostatectomy (RP) specimens and to evaluate its prognostic significance. PATIENTS AND METHODS Of 174 consecutive patients undergoing RP, 128 diagnosed as having PZ cancer (PZC) were enrolled. The maximum tumour area (MTA) and maximum tumour volume (MTV) in RP specimens were measured using digital planimetry. A circle with an area equal to the MTA, in which the central point was the intersection of the longest line of the MTA and the line perpendicularly bisecting the first line, was defined as a hypothetical extension area, regardless of anatomical structure. The area within this circle that did not overlap the MTA was defined as ,TA. RESULTS There was a significant correlation between the MTV and ,TA/MTA, introduced as a variable representing the degree of PZC extension along the anatomical shape of the PZ. The ,TA/MTA in patients with a MTV of >5 mL was significantly greater than that in those with a MTV of ,5 mL. Furthermore, ,TA/MTA was significantly associated with several prognostic indicators, including extracapsular extension, surgical margin status and perineural invasion. Multivariate analysis identified ,TA/MTA in addition to preoperative serum prostate-specific antigen level, extracapsular extension and surgical margin status as independent predictors of biochemical recurrence after RP. CONCLUSIONS PZC tends to extend along the anatomical shape of the PZ during progression, resulting in higher ,TA/MTA value in advanced PZC than that in early PZC. [source] Values that create value: socially responsible business practices in SMEs , empirical evidence from German companiesBUSINESS ETHICS: A EUROPEAN REVIEW, Issue 1 2009Eva-Maria Hammann Socially responsible business and ethical behaviour of companies have been of interest to academia and practice for decades. But the focus has almost exclusively been on large corporations while small- and medium-sized enterprises (SME) have not received as much attention. Thus, this paper focuses on socially responsible business practices of SME entrepreneurs or owner,managers in Germany. Based on the assumption that decision-makers in SMEs are the central point where all business activities start, members of a German entrepreneurs association were approached in the course of a qualitative and quantitative survey. They were asked to assess in what way their social responsibility is expressed in specific management practices towards selected stakeholder groups. These practices in turn were assumed to result in perceived positive reactions of the respective stakeholders and subsequently to positively influence the firm's financial performance, i.e. cost reductions and increase in profits. In the paper, a research model is presented that elaborates the relationship between an SME executive's social responsibility and the value creation of a firm, i.e. whether (personal) values create (economic) value. It was found that socially responsible management practices towards employees, customers and to a lesser extent society have a positive impact on the firm and its performance. As such, values can create additional value. [source] Bony landmarks as an aid for intraoperative facial nerve identificationCLINICAL ANATOMY, Issue 7 2007L.M. Greyling Abstract Identification of the facial nerve trunk is essential during surgery of the parotid gland. Numerous landmarks have been researched and used. The relation between the facial nerve to two constant bony landmarks, the tip of the mastoid process and the central point of the transverse process of the atlas was investigated. Forty cadavers were dissected. A preauricular incision exposed the nerve trunk. Bony landmarks were identified and marked. The distance from the nerve trunk to the mastoid process and the atlas was measured. The mean distance between the mastoid process and nerve for the left was 9.18 ± 2.05 mm and for the right, 9.35 ± 1.67 mm. The mean distance between the atlas and the nerve for the left was 14.31 ± 3.59 mm and for the right, 13.76 ± 4.65 mm. Confidence intervals were determined. The importance of the aforementioned data revolves around minimizing the chance of injury to the facial nerve during surgery. The applicability of these landmarks needs to be studied in the clinical setting. Clin. Anat. 20:739,744, 2007. © 2007 Wiley-Liss, Inc. [source] Comparison of human and porcine aortic valvesCLINICAL ANATOMY, Issue 3 2003Eugene K.W. Sim Abstract We compared the anatomy of human and porcine aortic valves. Porcine hearts were collected from the abattoir. Human hearts from patients who had died of non-cardiac causes were examined in the mortuary; only undamaged and anatomically normal hearts were used. Silicon casts were prepared by injecting engineering silicon at 80 mm Hg into the aortic arch. Various features of the aortic valve were measured: circumference, length between the commissural end point and central point of coaptation, surface diameter, and surface area. In total, 12 porcine and 12 human aortic valves were studied. The average circumferences of the human and porcine aortic valves were 8.00 ± 0.2 (SD) cm and 7.90 ± 1.0 cm, respectively. The central point of coaptation in human valves was skewed toward the left coronary cusp, whereas in porcine valves it was skewed toward the non-coronary cusp. In human aortic valves, the non-coronary cusp had the largest surface diameter and surface area with mean measurements of 3.6 ± 0.2 cm and 1.230 ± 0.228 cm2, respectively; the left coronary cusp was smallest for the same variables with measurements of 3.1 ± 0.3 cm and 0.898 ± 0.357 cm2. In porcine valves, the right coronary cusp had the largest surface diameter and surface area with mean measurements of 3.9 ± 0.7 cm and 1.716 ± 0.81 cm2, respectively; the non-coronary cusp was the smallest for the same variables with measurements of 2.9 ± 0.5 cm and 1.023 ± 0.659 cm2. These differences suggest that when using porcine valves as transplant material (e.g., stentless valves), geometric considerations, such as commissural length, may be important. Clin. Anat. 16:193,196, 2003. © 2003 Wiley-Liss, Inc. [source] Different combinations of salts affect the growth and bacteriocin production by Lactobacillus salivarius CRL 1328JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2010María Silvina Juárez Tomás Abstract BACKGROUND: The culture medium for optimal growth of vaginal Lactobacillus salivarius CRL 1328 is different from that for optimal bacteriocin production. To simultaneously obtain high amount of biomass and bacteriocin of this microorganism, the effects of different basal culture media and salts on both responses were evaluated. The study was performed by using a complete factorial experimental design 26, with central points. Sixty-four different growth media, which resulted from the combinations of two basal culture media and two concentrations of five salts (ammonium citrate, sodium acetate, MgSO4, MnSO4, and K2HPO4) were assayed. RESULTS: Only the addition of MnSO4 to each culture medium significantly stimulated the growth of L. salivarius. The presence of sodium acetate or MgSO4 stimulated the bacteriocin production, while MnSO4 and K2HPO4 exerted an inhibitory effect. However, the simultaneous addition of MnSO4 and sodium acetate to both basal culture media allowed high bacteriocin levels to be reached, attenuating the inhibitory effect of Mn2+. CONCLUSIONS: The application of a complete experimental design contributed to simultaneous optimization of the biomass and bacteriocin production of L. salivarius CRL 1328. The results obtained are potentially applicable to the technological production of probiotic bacteria and antagonistic substance to be included in a probiotic pharmaceutical product. Copyright © 2009 Society of Chemical Industry [source] ODOR PERCEPTION OVER LIQUID EMULSIONS CONTAINING SINGLE AROMA COMPOUNDS: EFFECTS OF AROMA CONCENTRATION AND OIL VOLUME FRACTIONJOURNAL OF SENSORY STUDIES, Issue 6 2002CHANTAL BROSSARD ABSTRACT This study aimed to check the hypothesis that aroma concentration in the aqueous phase of an oil-in-water emulsion controlled the odor intensity of single aroma compounds. A set of flavored oil-in-water emulsions, prepared according to a 22 experimental design (aroma concentration, oil volume fraction) with two central points, was assessed for odor intensity by a 24-member panel during four sessions. In each session, three of the four-studied aroma molecules (benzaldehyde, ethyl butyrate, linalool and acetophenone) were investigated. Whatever the aroma, the experimental data showed that the oil volume fraction of the emulsion (from 0.12 to 0.48) did not influence the odor intensity. For each emulsion composition, aroma concentrations at equilibrium in both phases were calculated using the oil-water partition coefficient of the compound. Odor intensities, estimated from aroma concentration in the aqueous phase using previously reported modeling of odor intensity above water solutions, were then compared to experimental data. It is confirmed that the perceived odor intensity is governed by the aroma concentration in the aqueous phase at the time of the trial and not by the averaged apparent concentration in the emulsion. [source] | ||||||||||||||||