bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolic syndrome and new onset diabetes after transplantation in kidney transplant recipients
Authors: Luan Fu L. , Langewisch Eric , Ojo Akinlolu
Published: December 2009

Luan FL, Langewisch E, Ojo A. Metabolic syndrome and new onset diabetes after transplantation in kidney transplant recipients.  Clin Transplant 2010: 24: 778–783. © 2009 John Wiley & Sons A/S.

Abstract:  Background:  Metabolic syndrome (MS) and new onset diabetes after transplant (NODAT) are common in kidney transplant patients. We studied the relationship between the two conditions and their impact on metabolic and cardiovascular risk profiles.

Methods:  All non‐diabetic patients transplanted between 1999 and 2005 who were followed up to 2006 were included. MS and NODAT were determined. Kaplan–Meier survival and various regression analyses were performed to determine the clinical correlates for both conditions and their association with various cardiovascular risk factors.

Results:  Among 591 patients, 314 (53.1%) had MS and 90 (15.2%) developed NODAT. The two conditions were highly associated with each other as 84 patients with NODAT also had MS (14.2%). Elevated body mass index and fasting glucose levels at transplant were risk factors for both conditions, whereas weight gain after transplant was associated only with MS. African American, old age, and hypertension‐related ESRD were risk factors for NODAT. Finally, the presence of MS was associated with reduced kidney function and elevated uric acid levels, whereas the presence of NODAT with elevated pulse pressure.

Conclusions:  MS and NODAT are highly prevalent and significantly associated with impaired metabolic and cardiovascular risk profiles. Early identification of such conditions may facilitate targeted therapeutic intervention.
Transplantation with pancreas after living donor kidney vs. living donor kidney alone in type 1 diabetes mellitus recipients*
Authors: Sampaio Marcelo Santos , Poommipanit Neda , Cho Yong Won , Shah Tariq , Bunnapradist Suphamai
Published: December 2009

Sampaio MS, Poommipanit N, Cho YW, Shah T, Bunnapradist S. Transplantation with pancreas after living donor kidney vs. living donor kidney alone in type 1 diabetes mellitus recipients.  Clin Transplant 2010: 24: 812–820. © 2009 John Wiley & Sons A/S.

Abstract:  Living donor kidney transplantation (LDKT) in type 1 diabetic recipients (T1DM) may be followed by a pancreas after living donor kidney (PALK). The impact of the PALK is largely unknown. Adult T1DM living donor kidney recipients (1997–2007) listed for pancreas transplantation were divided into those who subsequently received pancreas transplantation and those who did not (living donor kidney transplant alone [LDKA]). Outcomes were compared. A sub‐analysis was performed in recipients with at least one yr of kidney graft survival and limiting PALK to those who underwent pancreas transplantation in the first year. Of 4554 recipients, 23% received PALK. PALK had more favorable baseline characteristics. At the end of eight yr, we found significantly superior patient (85% vs. 75%) and kidney graft survival (75% vs. 62%) in PALK group. The adjusted hazard ratios of PALK (LDKA as reference) were 0.65 (95%CI: 0.52–0.81) for death and 0.63 (0.54–0.76) for renal graft loss. In sub‐group analysis, there was a trend toward decreased death in PALK (HR = 0.78: 0.57–1.07). In conclusion, only 23% of those wait‐listed received a pancreas with patient and kidney survival superior to LDKA. Pancreas transplant in the first year after kidney transplant was associated with a trend toward better long‐term patient survival.
Management of flood victims: Chainat Province, central Thailand
Authors: Wisitwong Anchaleeporn , McMillan Margaret
Published: December 2009

This article focuses on the processes of flood management and the experiences of flood victims in Chainat Province, central Thailand, so as to develop knowledge about the future handling of such disasters. A phenomenological qualitative approach was used to describe the processes of providing assistance to flood victims. In‐depth interviews and observation were used to collect the data. Criterion sampling was used to select 23 participants. Content analysis of the data revealed that some flood victims could predict flooding based on prior experiences, so they prepared themselves. The data revealed six themes that demonstrated that those who could not predict how floods would impact on them were unprepared and suffered losses and disruption to their daily life. Damaged routes meant people could not go to work, resulting in the loss of income. There was a lack of sanitary appliances and clean drinking water, people were sick, and experienced stress. At the community level, people helped one another, making sandbags and building walls as a defense against water. They formed support groups to enable the processing of stressful experiences. However, later, the water became stagnant and contaminated, creating an offensive smell. The government provided assistance to cut off electricity services, food and water, toilets and health services, and water drainage. In the recovery phase, the victims needed money for investment, employment opportunities, books for children, extra time to pay off loans, reconnection of electricity, surveys of damage, and pensions to deal with damage and recovery.
Embedded Implicit Stand‐Ins for Animated Meshes: A Case of Hybrid Modelling
Authors: Kravtsov D. , Fryazinov O. , Adzhiev V. , Pasko A. , Comninos P.
Published: January 2010

In this paper, we address shape modelling problems, encountered in computer animation and computer games development that are difficult to solve just using polygonal meshes. Our approach is based on a hybrid‐modelling concept that combines polygonal meshes with implicit surfaces. A hybrid model consists of an animated polygonal mesh and an approximation of this mesh by a convolution surface stand‐in that is embedded within it or is attached to it. The motions of both objects are synchronised using a rigging skeleton. We model the interaction between an animated mesh object and a viscoelastic substance, which is normally represented in an implicit form. Our approach is aimed at achieving verisimilitude rather than physically based simulation. The adhesive behaviour of the viscous object is modelled using geometric blending operations on the corresponding implicit surfaces. Another application of this approach is the creation of metamorphosing implicit surface parts that are attached to an animated mesh. A prototype implementation of the proposed approach and several examples of modelling and animation with near real‐time preview times are presented.
Neurotransmission in Parkinson’s disease: beyond dopamine
Authors: Barone P.
Published: December 2009

Parkinson’s disease (PD) is most frequently associated with characteristic motor symptoms that are known to arise with degeneration of dopaminergic neurons. However, patients with this disease also experience a multitude of non‐motor symptoms, such as sleep disturbances, fatigue, apathy, anxiety, depression, cognitive impairment, dementia, olfactory dysfunction, pain, sweating and constipation, some of which can be at least as debilitating as the movement disorders and have a major impact on patients’ quality of life. Many of these non‐motor symptoms may be evident prior to the onset of motor dysfunction. The neuropathology of PD has shown that complex, interconnected neuronal systems, regulated by a number of different neurotransmitters in addition to dopamine, are involved in the aetiology of motor and non‐motor symptoms. This review focuses on the non‐dopaminergic neurotransmission systems associated with PD with particular reference to the effect that their modulation and interaction with dopamine has on the non‐motor symptoms of the disease. PD treatments that focus on the dopaminergic system alone are unable to alleviate both motor and non‐motor symptoms, particularly those that develop at early stages of the disease. The development of agents that interact with several of the affected neurotransmission systems could prove invaluable for the treatment of this disease.
Apraxia in Parkinson’s disease and multiple system atrophy
Authors: Uluduz D. , Ertürk Ö. , Kenangil G. , Özekmekçi S. , Ertan S. , Apaydin H. , Erginöz E.
Published: December 2009

Objective:  To determine praxis function in patients with Parkinson’s disease (PD) and multiple system atrophy (MSA).

Methods:  Nineteen patients with PD and 16 patients with probable MSA were recruited into study. Twenty‐five age‐matched, healthy subjects were included as controls. The Mayo Clinic praxis test battery was applied. Pantomime tasks, including oral/facial, trunk, and upper extremity movement, were used to evaluate ideomotor apraxia (IMA). Sequential tasks, including Luria test for ideational apraxia (IDA) and use of actual objects, were also tested. In addition, Standardized Mini Mental Test (MMSE), Hamilton Depression (HAM‐D), and Anxiety (HAM‐A) Scales were used.

Results:  Mean ages of the study participants were 66 ± 7, 68 ± 5, and 65 ± 7 years in PD, MSA, and control groups, respectively. Mean total praxis score was significantly lower for patients with PD (92.4 ± 4) and MSA (75.9 ± 18) than for controls (97.4 ± 2) (P = 0.000). Transitive performances of upper extremities and sequential tasks were significantly impaired in patients with PD compared to control subjects (P < 0.05). There was no correlation between total praxis scores and sum scores of tremor, bradykinesia, and rigidity of both of the upper limbs of patients with PD. Subgroup praxis scores were substantially worse in MSA group (P < 0.0001). Compared to control subjects, mean scores for MMSE, HAM‐D, and HAM‐A tests were significantly worse in MSA group, but, for PD patient group, only HAM‐A scores were worse.

Conclusion:  Our results indicate that although not a presenting symptom, IMA and IDA may be features of MSA and, to a lesser degree, of PD. Also, it seems to be unrelated to the motor features of patients with PD.
Chronic cognitive sequelae after traumatic brain injury are not related to growth hormone deficiency in adults
Authors: Pavlovic D. , Pekic S. , Stojanovic M. , Zivkovic V. , Djurovic B. , Jovanovic V. , Miljic N. , Medic‐Stojanoska M. , Doknic M. , Miljic D. , Djurovic M. , Casanueva F. , Popovic V.
Published: December 2009

Objective:  The objective of the study was to asses the possible influence of hypothalamo–pituitary deficiencies, and growth hormone (GH) deficiency in particular, on cognition in adult patients with traumatic brain injury (TBI). TBI is a recently identified risk factor for cognitive deficits and hypopituitarism. Even the patients with favorable outcome after TBI may present with persistent bodily, psychosocial, and cognitive impairments, resembling patients with untreated partial or complete pituitary insufficiency.

Design:  We performed retrospective and cross‐sectional study of endocrine and cognitive function in TBI in 61 patients (aged 37.7 ± 1.7 years) of both sexes (44 m,17 f), at least 1 year after TBI (3.9 ± 0.6 years). Serum insulin‐like growth factor 1 (IGF‐I), thyroxin, thyroid‐stimulating hormone (TSH), follicle‐stimulating hormone (FSH), luteinizing hormone (LH), testosterone (in men), prolactin, and cortisol were measured, and GH secretion was assessed by growth hormone releasing hormone (GHRH) + growth hormone releasing peptide‐6 (GHRP‐6) test. Cognitive function was assessed by using a standard neuropsychological battery.

Results:  GH deficiency (GHD) and GH insufficiency (GHI) were found in 20 patients (32.8%). After adjustment for confounders [age, body mass index (BMI), education level, time elapsed from TBI], there were no significant differences in results of neuropsychological tests between patients with TBI with GHD, GHI, and normal GH secretion. There were no correlations of neuropsychological variables with stimulated peak GH secretion or IGF‐I level.

Conclusions:  GHD persists long after the TBI, independently of trauma severity and age at traumatic event. GH secretion is more sensitive to TBI than other pituitary hormones. No evidence is found for an association of cognitive function impairment and somatotropic axis impairment in adult patients tested more than 1 year after the TBI.
Paraoxonase 1 (PON1) polymorphisms and risk for essential tremor
Authors: García‐Martín E. , Martínez C. , Alonso‐Navarro H. , Benito‐León J. , Puertas I. , Rubio L. , López‐Alburquerque T. , Agúndez J. A. G. , Jiménez‐Jiménez F. J.
Published: December 2009

Background:  The polymorphic enzyme human serum paraoxonase 1 (PON1), encoded by the gene PON1 (chromosome 7q21.3), plays a major role in the metabolism of organophosphorus compounds. We investigated the possible association between the PON1 genotype and allelic variants of the polymorphisms Leu55Met and Glu192Arg, and the risk for essential tremor (ET).

Methods:  We studied the frequency of the PON1 genotypes and allelic variants in 201 patients with ET and 220 healthy controls using a PCR‐RLFP method.

Results:  The frequencies of the PON1 genotypes and allelic variants of the polymorphisms Leu55Met and Gln192Arg did not differ significantly between patients with ET and controls. These polymorphisms were unrelated with the age of onset of ET.

Conclusions:  PON1 polymorphisms are not related with the risk for ET.
EFNS guideline on the management of status epilepticus in adults
Authors: Meierkord H. , Boon P. , Engelsen B. , Göcke K. , Shorvon S. , Tinuper P. , Holtkamp M.
Published: December 2009

The objective of the current article was to review the literature and discuss the degree of evidence for various treatment strategies for status epilepticus (SE) in adults. We searched MEDLINE and EMBASE for relevant literature from 1966 to January 2005 and in the current updated version all pertinent publications from January 2005 to January 2009. Furthermore, the Cochrane Central Register of Controlled Trials (CENTRAL) was sought. Recommendations are based on this literature and on our judgement of the relevance of the references to the subject. Recommendations were reached by informative consensus approach. Where there was a lack of evidence but consensus was clear, we have stated our opinion as good practice points. The preferred treatment pathway for generalised convulsive status epilepticus (GCSE) is intravenous (i.v.) administration of 4–8 mg lorazepam or 10 mg diazepam directly followed by 18 mg/kg phenytoin. If seizures continue more than 10 min after first injection, another 4 mg lorazepam or 10 mg diazepam is recommended. Refractory GCSE is treated by anaesthetic doses of barbiturates, midazolam or propofol; the anaesthetics are titrated against an electroencephalogram burst suppression pattern for at least 24 h. The initial therapy of non‐convulsive SE depends on type and cause. Complex partial SE is initially treated in the same manner as GCSE. However, if it turns out to be refractory, further non‐anaesthetising i.v. substances such levetiracetam, phenobarbital or valproic acid should be given instead of anaesthetics. In subtle SE, in most patients, i.v. anaesthesia is required.
Neurocognitive outcomes of individuals with a sex chromosome trisomy: XXX, XYY, or XXY: a systematic review*
Authors: LEGGETT VICTORIA , JACOBS PATRICIA , NATION KATE , SCERIF GAIA , BISHOP DOROTHY V M
Published: January 2010

Aim  To review systematically the neurodevelopmental characteristics of individuals with sex chromosome trisomies (SCTs).

Method  A bibliographic search identified English‐language articles on SCTs. The focus was on studies unbiased by clinical referral, with power of at least 0.69 to detect an effect size of 1.0.

Results  We identified 35 articles on five neonatally identified samples that had adequate power for our review. An additional 11 studies were included where cases had been identified for reasons other than neurodevelopmental concerns. Individuals with an additional X chromosome had mean IQs that were within broadly normal limits but lower than the respective comparison groups, with verbal IQ most affected. Cognitive outcomes were poorest for females with XXX. Males with XYY had normal‐range IQs, but all three SCT groups (XXX, XXY, and XYY) had marked difficulties in speech and language, motor skills, and educational achievement. Nevertheless, most adults with SCTs lived independently. Less evidence was available for brain structure and for attention, social, and psychiatric outcomes. Within each group there was much variation.

Interpretation  Individuals with SCTs are at risk of cognitive and behavioural difficulties. However, the evidence base is slender, and further research is needed to ascertain the nature, severity, and causes of these difficulties in unselected samples.
Sex Differences in Animal Models of Depression and Antidepressant Response
Authors: Dalla Christina , Pitychoutis Pothitos M. , Kokras Nikolaos , Papadopoulou‐Daifoti Zeta
Published: December 2009

Abstract: Many stress‐related mental disorders, including depression and post‐traumatic stress disorder occur more often in women than in men. While social and cultural factors certainly contribute to these differences, neurobiological sex differences seem to also play an important role. A rapidly burgeoning literature from basic and clinical research documents sex differences in brain anatomy, chemistry and function, as well as in stress and drug responses. For example, some clinical studies have reported that women may have a better outcome when treated with selective serotonin re‐uptake inhibitors, in comparison to tricyclic antidepressants. Furthermore, relatively limited basic research has been devoted to developing animal models and consequently describing drug treatments which are sensitive to sex differences. In this MiniReview, we discuss sex differences in behavioural aspects, as well as neurochemical, neurobiological and pharmacological findings that we have collected from several different animal models and tests of depression. These are the forced swim test, the chronic mild stress and the learned helplessness models, the Flinders sensitive line rats, which is a genetic model of depression and the lipopolysaccharide‐induced sickness behaviour, a putative inflammatory model of depression. Collectively, our data have shown that in all animal models assayed, serotonergic neurochemical responses were differently affected in males and females, ultimately producing sex‐dependent behavioural effects. In addition, Flinders sensitive line rats exhibited a sexually dimorphic response to chronic antidepressant treatment. These sex‐differentiated neurochemical and behavioural alterations lend support to a major role of serotonin in the mediation of sexually dimorphic responses.
Environmental Exposure to Methylmercury is Associated with a Decrease in Nitric Oxide Production
Authors: De Marco Kátia Cristina , Passos Carlos J.S. , Sertorio Jonas , Tanus‐Santos José Eduardo , Barbosa Fernando
Published: December 2009

Abstract:  Some studies have recently suggested that mercury (Hg)‐exposed populations face increased risks of cardiovascular diseases, and experimental data indicate that such risks might be due to reductions in nitric oxide bioavailability. However, no previous study has examined whether Hg exposure affects plasma nitrite concentrations in humans as an indication of nitric oxide production. Here, we investigated whether there is an association between circulating nitrite and Hg concentrations in whole blood, plasma and hair from an exposed methylmercury (MeHg) population. Hair and blood samples were collected from 238 persons exposed to MeHg from fish consumption. Hg concentrations in plasma (PHg), whole blood (BHg) and hair Hg (HHg) were determined by inductively coupled plasma‐mass spectrometry. Mean BHg content was 49.8 ± 35.2 μg/l, mean PHg was 7.8 ± 6.9 μg/l and HHg 14.6 ± 10.6 μg/g. Mean plasma nitrite concentration was 253.2 ± 105.5 nM. No association was found between plasma nitrite concentration and BHg or HHg concentrations in a univariate model. However, multiple regression models adjusted for gender, age and fish consumption showed a significant association between plasma nitrite and plasma Hg concentration (β = −0.1, p < 0.001). Our findings constitute preliminary clinical evidence that exposure to MeHg may cause inhibitory effects on the production of endothelial nitric oxide.
Model‐Based Neutrophil‐Guided Dose Adaptation in Chemotherapy: Evaluation of Predicted Outcome with Different Types and Amounts of Information
Authors: Wallin Johan E. , Friberg Lena E. , Karlsson Mats O.
Published: December 2009

Abstract:  One of the most employed approaches to reduce severe neutropenia following anticancer drug regimens is to reduce the consecutive dose in fixed steps, commonly by 25%. Another approach has been to use pharmacokinetic (PK) sampling to tailor dosing, but only rarely have model‐based computer approaches utilizing collected PK and/or pharmacodynamic (PD) data been used. A semi‐mechanistic model for myelosuppression that can characterize the interindividual and interoccasion variability in the time‐course of neutrophils following administration of a wide range of anticancer drugs may be used in a clinical setting for model‐based dose individualization. The aim of this study was to compare current stepwise procedures to model‐based dose adaptation by simulations, and investigate if the overall dose intensity in the population could be increased without increasing the risk of severe toxicity. The value of various amounts of PK‐ and/or PD‐information was compared to standard dosing strategies using a maximum a posteriori procedure in NONMEM. The results showed that when information on neutrophil counts was available, the additional improvement from PK sampling was negligible. Using neutrophil sampling at baseline and an observation near the predicted nadir increased the number of patients in the target range by 27% in comparison with a one‐sided 25% dose adjustment schedule, while keeping the number of patients experiencing severe toxicity at a comparable low level after five courses of treatment. High interindividual variability did not limit the benefit of model‐based dose adaptation, whereas high interoccasion variability was predicted to make any dose adaptation method less successful. This study indicates that for successful model‐based dose adaptation clinically, there is no need for drug concentration sampling, and that one extra neutrophil measurement in addition to the pre‐treatment value is sufficient to limit severe neutropenia while increasing dose intensity.
Sexually Transmitted Diseases and Sexual Function
Authors: Sadeghi-Nejad Hossein , Wasserman Marlene , Weidner Wolfgang , Richardson Daniel , Goldmeier David
Published: January 2010

Introduction

There is a need for state-of-the-art information in the area of sexually transmitted infections (STIs) in relation to sexual function. There are an estimated 60 million people living with and 340 million with treatable STIs. Surveys show sexual problems to be as high as 35% for men and 55% for women; however, there is little research directly assessing relationships between infection and sexual function.

Aim

To show that STIs are associated with (and may cause) sexual dysfunction. Conversely, sexual dysfunction can increase patients’ risk of STI acquisition. In men, erectile dysfunction (ED) associated with condom use may lead to unsafe sexual practices and, hence, STI acquisition. The role of various therapies including phosphodiesterase type 5 inhibitors in the treatment of ED in positive men taking social drugs will be explored.

Methods

To provide state-of-the-art knowledge concerning sexual function and STIs, representing the opinions of five experts from four countries developed in a consensus process and encompassing a detailed literature review over a 2-year period.

Main Outcome Measure

Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate.

Results

This article highlights major factors causing the spread of STIs and suggests management interventions to prevent further spread of HIV/STIs, focusing on the juxtaposition between STIs and sexual functioning. Women’s unique vulnerabilities to HIV/STIs (biological and physiological issues, gender-based violence, gender inequity) and their impact on women’s sexual function are reviewed. Similarly, men’s unique vulnerabilities to HIV/STIs including condom use, disclosure, voluntary counseling and testing, multiple concurrent sexual partners, and recreational drug use—particularly in homosexual men—are explored, as is the association of prostatitis and sexual function. Lastly, the article reviews the relationship between circumcision and sexual dysfunction.

Conclusions

A multidimensional approach to achieve optimal treatment outcomes should be embraced.
Single-Loop System Reliability-Based Design Optimization Using Matrix-Based System Reliability Method: Theory and Applications
Authors: Nguyen Tam H. , Song Junho , Paulino Glaucio H.
Published: December 2009

This paper proposes a single-loop system reliability-based design optimization (SRBDO) approach using the recently developed matrix-based system reliability (MSR) method. A single-loop method was employed to eliminate the inner-loop of SRBDO that evaluates probabilistic constraints. The MSR method enables us to compute the system failure probability and its parameter sensitivities efficiently and accurately through convenient matrix calculations. The SRBDO/MSR approach proposed in this paper is applicable to general systems including series, parallel, cut-set, and link-set system events. After a brief overview on SRBDO algorithms and the MSR method, the SRBDO/MSR approach is introduced and demonstrated by three numerical examples. The first example deals with the optimal design of a combustion engine, in which the failure is described as a series system event. In the second example, the cross-sectional areas of the members of a statically indeterminate truss structure are determined for minimum total weight with a constraint on the probability of collapse. In the third example, the redistribution of the loads caused by member failures is considered for the truss system in the second example. The results based on different optimization approaches are compared for further investigation. Monte Carlo simulation is performed in each example to confirm the accuracy of the system failure probability computed by the MSR method.
Trajectory Control of Compliant Parallel-Arm Mechanisms
Authors: Tekeş Ayşe , Sönmez Ümit , Güvenç Bilin Aksun
Published: December 2009

In this paper, a compliant parallel-arm mechanism design with a desired trajectory control is investigated. The compliant parallel-arm mechanism consists of two large-deflecting initially straight beams and a rigid coupler. The coupler is assumed to be actuated by a magnetic force drive with an obtainable force history. This compliant parallel-arm mechanism can be used as an indexing mechanism or a dwell mechanism if the rigid coupler horizontal trajectory includes stops at a certain horizontal displacement (rise) and it also includes waiting periods at the specified rise for a desired duration. This trajectory is achieved by using a conventional proportional-integral-derivative type trajectory controller that uses position, velocity, and acceleration information. The theory and the presented results are checked by several methods, including geometrically nonlinear finite element analysis, then a simulation based method, and finally an experimental method. The experimental setup is constructed based on a reverse engineering concept to validate the theory and to confirm the simulation results.
Mechanical Spring Replacement With Pneumatic Return Device in a Valve Train: Effects on Dynamics and Preload Tuning
Authors: Stefano Pastorelli , Andrea Almondo , Massimo Sorli
Published: December 2009

The paper presents a comparison of performance for a cam transmission of an engine valve train operating with a mechanical spring and with a return spring device that uses a pneumatic spring. Dynamic analysis of the cam mechanism is performed in the frequency and time domains employing a combined lumped-distributed parameter model capable of predicting the effects of the higher harmonics of the cam lift profile on system performance, in particular of the return spring device. Dynamic stiffness of the transmission in the frequency domain and time history of the contact force between cam and follower are evaluated. The limits of the traditional mechanical spring-closing system at high-speed camshaft operations are investigated, highlighting that they are mainly imposed by the internal resonances of the spring. The pneumatic spring is an improved replacement of the steel spring because of better dynamic behavior. Furthermore, the pneumatic return device allows preload tuning of the spring, which may increase transmission efficiency through proper control of the fluid pressure. Study of the pressure control circuit is also presented.
Modularity and Ease of Disassembly: Study of Electrical and Electronic Equipment
Authors: Collado-Ruiz Daniel , Capuz-Rizo Salvador F.
Published: December 2009

A common recommendation when designing for disassembly is to develop more modular products. The common belief is that an increase in modularity will systematically reduce the time required in order to disassemble the product, reducing the cost of the process. This paper studies the statistical relationship between these two concepts by comparing 15 different electrical products. Modularity and disassembly performance are assessed by different indicators each and their correlation is analyzed. The results show that the aforementioned relationship cannot be statistically proven and, for some of the cases, even inverse correlation is found. Factors such as product structure or selected end-of-life strategy are more important than modularity in end-of-life performance. Systematic modularization can even result in products with a worse behavior: For most electrical equipment, generating modules from a functional or manufacturing point of view will most probably result in worse end-of-life performance. It is only for modules with very specific properties that performance can be guaranteed.
An Approach to Power-Flow and Static Force Analysis in Multi-Input Multi-Output Epicyclic-Type Transmission Trains
Authors: Esmail Essam L. , Hassan Shaker S.
Published: December 2009

This study contributes to the development of a systematic methodology for the torque and power-flow analyses of multi-input multi-output (MIMO) epicyclic gear mechanisms (EGMs) with or without reaction link based on the concept of fundamental circuit. The studies on power-flow analysis of EGMs are mostly done in the context of efficiency formulations. In the opinion of the authors, the design process of the MIMO mechanism involves not only finding the configuration that provides the correct velocity ratios but also meeting other kinematic requirements and ensuring that the two inputs have a mutually constructive nature. To demonstrate the analysis, a new motor/generator integrated hybrid transmission design is used to show how the torque acting on each link of an epicyclic gear train (EGT) can be systematically solved in terms of input torque(s) and/or controlled output torque. This paper presents a unification of kinematic and torque balance approaches for the analysis of MIMO epicyclic-type transmission trains. The results presented are meant to deepen the knowledge as to how and why a MIMO epicyclic-type transmission should operate in a certain way under the given conditions. In the process, this paper explores the theoretical bases of operation of the Toyota Hybrid System and the root cause of some confusion in the field of EGTs.
Tooth Surface Error Correction for Face-Hobbed Hypoid Gears
Authors: Fan Qi
Published: December 2009

Face-hobbing is a continuous generating process employed in manufacturing spiral bevel and hypoid gears. Due to machining dynamics and tolerances of machine tools, the exact tooth surface geometry may not be obtained from the machining process using theoretical machine tool settings. Repeatable tooth surface geometric errors may be observed. The tooth surface errors will cause unfavorable displacement of tooth contact and increased transmission errors, resulting in noisy operation and premature failure due to edge contact and highly concentrated stresses. In order to eliminate the tooth surface errors and ensure precision products, a corrective machine setting technique is employed to modify the theoretical machine tool settings, compensating for the surface errors. This paper describes a method of correcting tooth surface errors for spiral bevel and hypoid gears generated by the face-hobbing process using computer numerically controlled hypoid gear generators. Polynomial representation of the universal motions of machine tool settings is considered. The corrective universal motion coefficients are determined through an optimization process with the target of minimization of the tooth surface errors. The sensitivity of the changes of the tooth surface geometry to the changes of universal motion coefficients is investigated. A numerical example of a face-hobbed hypoid pinion is presented.
Lipid Rafts As a Membrane-Organizing Principle
Authors: Lingwood Daniel , Simons Kai
Published: December 2009

Lipid Rafts Come of Age

Living cells are surrounded by cellular membranes composed of lipids and proteins. Much attention has been paid to the biogenesis and sorting of membrane proteins. The dynamics and sorting of lipids have been much more difficult to study.
Lingwood and Simons
(p.
46
) review the evidence for, and the role played by, so-called lipid rafts—laterally segregated regions within membranes enriched for particular lipids and proteins.
Structure and Mechanisms of a Protein-Based Organelle in
Escherichia coli
Authors: Tanaka Shiho , Sawaya Michael R. , Yeates Todd O.
Published: December 2009

Bacterial Compartmentalization

In diverse bacteria, reactions that involve toxic or volatile metabolites are carried out by enzymes inside proteinaceous microcompartments.

Tanaka
et al.

(p.
81
; see the Perspective by

Kang and Douglas

) now report high-resolution crystal structures for four homologous proteins that are constituents of the shell that sequesters the metabolism of ethanolamine in bacteria. While the structures have similar overall folds, they have distinctive structural features that provide insight into how they build the shell and participate in microcompartment function.
238
U/
235
U Variations in Meteorites: Extant
247
Cm and Implications for Pb-Pb Dating
Authors: Brennecka G. A. , Weyer S. , Wadhwa M. , Janney P. E. , Zipfel J. , Anbar A. D.
Published: January 2010

How to Get a Date

Radiometric dating relies on measuring the abundance of a radioactive isotope and/or its decay products. By knowing a decay rate and an isotopic starting abundance—both assumed to be constant—an age is determined. Using high-resolution mass spectrometry,

Brennecka
et al.

(p.
449
, published online 31 December; see the Perspective by

Connelly

) show that the known starting abundance of
238
U and
235
U isotopes in meteorites, which decay into
206
Pb and
207
Pb, respectively, is actually quite variable. Trace amounts of
247
Cm in the early solar system may have unexpectedly contributed additional
235
U, skewing the ratio. Pb-Pb dating, the method commonly used to date early solar system materials, may thus need a correction of up to 5 million years.
Prdm9
Controls Activation of Mammalian Recombination Hotspots
Authors: Parvanov Emil D. , Petkov Petko M. , Paigen Kenneth
Published: January 2010

Homing in on Hotspots

The clustering of recombination in the genome, around locations known as hotspots, is associated with specific DNA motifs. Now, using a variety of techniques, three studies implicate a chromatin-modifying protein, the histone-methyltransferase PRDM9, as a major factor involved in human hotspots (see the Perspective by

Cheung
et al.

).

Parvanov
et al.

(p.
835
, published online 31 December) mapped the locus in mice, and analyzed allelic variation in mice and humans, whereas

Myers
et al.

(p.
876
, published online 31 December) used a comparative analysis between human and chimpanzees to show that the recombination process leads to a self-destructive drive in which the very motifs that recruit hotspots are eliminated from our genome.

Baudat
et al.

(p.
836
, published online 31 December) took this analysis a step further to identify human allelic variants within Prdm9 that differed in the frequency at which they used hotspots. Furthermore, differential binding of this protein to different human alleles suggests that this protein interacts with specific DNA sequences. Thus, PDRM9 functions in the determination of recombination loci within the genome and may be a significant factor in the genomic differences between closely related species.
Unveiling the Transient Template in the Self-Assembly of a Molecular Oxide Nanowheel
Authors: Miras Haralampos N. , Cooper Geoffrey J. T. , Long De-Liang , Bögge Hartmut , Müller Achim , Streb Carsten , Cronin Leroy
Published: December 2009

A Hidden Template

The entropic challenge inherent in forming a ring-shaped molecule generally increases considerably with the size of the ring. Assuming that a linear precursor must bind its ends together, extending its length diminishes the likelihood of the opposite ends approaching one another. In the absence of an external force, how then can a family of molybdenum oxide rings, several nanometers in diameter (quite large at the molecular scale), self-assemble?

Miras
et al.

(p.
72
, see the cover; see the Perspective by

Whitmire

) have now uncovered an internal template guiding the process. By carefully controlling conditions in a flow reactor, they were able to halt the assembly process partway through and characterize a smaller molybdenum oxide core cluster, around which the larger ring was forming. Ejection of this template then yielded the hollow finished product.
Drive Against Hotspot Motifs in Primates Implicates the
PRDM9
Gene in Meiotic Recombination
Authors: Myers Simon , Bowden Rory , Tumian Afidalina , Bontrop Ronald E. , Freeman Colin , MacFie Tammie S. , McVean Gil , Donnelly Peter
Published: January 2010

Homing in on Hotspots

The clustering of recombination in the genome, around locations known as hotspots, is associated with specific DNA motifs. Now, using a variety of techniques, three studies implicate a chromatin-modifying protein, the histone-methyltransferase PRDM9, as a major factor involved in human hotspots (see the Perspective by

Cheung
et al.

).

Parvanov
et al.

(p.
835
, published online 31 December) mapped the locus in mice, and analyzed allelic variation in mice and humans, whereas

Myers
et al.

(p.
876
, published online 31 December) used a comparative analysis between human and chimpanzees to show that the recombination process leads to a self-destructive drive in which the very motifs that recruit hotspots are eliminated from our genome.

Baudat
et al.

(p.
836
, published online 31 December) took this analysis a step further to identify human allelic variants within Prdm9 that differed in the frequency at which they used hotspots. Furthermore, differential binding of this protein to different human alleles suggests that this protein interacts with specific DNA sequences. Thus, PDRM9 functions in the determination of recombination loci within the genome and may be a significant factor in the genomic differences between closely related species.
Leaping Lizards
Lizards in an Evolutionary Tree
Ecology and Adaptive Radiation of Anoles

by Jonathan B. Losos

University of California Press, Berkeley, 2009. 527 pp. $75, £52. ISBN 9780520255913. Organisms and Environments.
Authors: Gillespie Rosemary G.
Published: December 2009

Losos offers a comprehensive synthesis of research on the adaptive radiation of anoline lizards in the Caribbean.
Darwinian Evolution of Prions in Cell Culture
Authors: Li Jiali , Browning Shawn , Mahal Sukhvir P. , Oelschlegel Anja M. , Weissmann Charles
Published: January 2010

DNA-less Evolution

Prions are proteinaceous infectious elements involved in a variety of neurodegenerative diseases, including scrapie in sheep and so-called mad cow disease in cattle. Now

Li
et al.

(p.
869
, published online 31 December) show that, when propagated in tissue culture cells, cloned prion populations become diverse by mutational events and can undergo selective amplification. Thus, even though devoid of a coding genome, prions, when propagated under a particular selection regime, can be subject to rapid evolution.
Polarization-Induced Hole Doping in Wide–Band-Gap Uniaxial Semiconductor Heterostructures
Authors: Simon John , Protasenko Vladimir , Lian Chuanxin , Xing Huili , Jena Debdeep
Published: December 2009

Activating Stubborn Dopants

Many applications of semiconductor light-emitting diodes and lasers, such as reading optical disks, benefit from shorter wavelengths, but this requires materials with larger energy gaps between their valance and conduction bands. The electronic conductivity of these materials often has to be increased by doping with impurity atoms. However, in nitride materials, such as GaN and AlGaN, hole doping with acceptor atoms such as Mg is ineffective at room temperature.

Simon
et al.

(p.
60
) grew a gradient of AlGaN on the surface of GaN and found that the polarization of the layer could field-ionize the acceptor dopants efficiently at room temperature. The heterostructure was used successfully in a light-emitting diode that emits in the ultraviolet.
PRDM9 Is a Major Determinant of Meiotic Recombination Hotspots in Humans and Mice
Authors: Baudat F. , Buard J. , Grey C. , Fledel-Alon A. , Ober C. , Przeworski M. , Coop G. , de Massy B.
Published: January 2010

Homing in on Hotspots

The clustering of recombination in the genome, around locations known as hotspots, is associated with specific DNA motifs. Now, using a variety of techniques, three studies implicate a chromatin-modifying protein, the histone-methyltransferase PRDM9, as a major factor involved in human hotspots (see the Perspective by

Cheung
et al.

).

Parvanov
et al.

(p.
835
, published online 31 December) mapped the locus in mice, and analyzed allelic variation in mice and humans, whereas

Myers
et al.

(p.
876
, published online 31 December) used a comparative analysis between human and chimpanzees to show that the recombination process leads to a self-destructive drive in which the very motifs that recruit hotspots are eliminated from our genome.

Baudat
et al.

(p.
836
, published online 31 December) took this analysis a step further to identify human allelic variants within Prdm9 that differed in the frequency at which they used hotspots. Furthermore, differential binding of this protein to different human alleles suggests that this protein interacts with specific DNA sequences. Thus, PDRM9 functions in the determination of recombination loci within the genome and may be a significant factor in the genomic differences between closely related species.
If Our Messages Are To Be Heard
Don't Be Such a Scientist
Talking Substance in an Age of Style

by Randy Olson

Island Press, Washington, DC, 2009. 215 pp., illus. Paper, $19.95. ISBN 9781597265638.
Am I Making Myself Clear?
A Scientist's Guide to Talking to the Public

by Cornelia Dean

Harvard University Press, Cambridge, MA, 2009. 284 pp. $19.95, £14.95, €18. ISBN 9780674036352.
Authors: Kareiva Peter
Published: December 2009

Olson and Dean present two rather different approaches scientists can take to improve their ability to communicate with the public.
Detection of Gamma-Ray Emission from the Vela Pulsar Wind Nebula with AGILE
Authors: Pellizzoni A. , Trois A. , Tavani M. , Pilia M. , Giuliani A. , Pucella G. , Esposito P. , Sabatini S. , Piano G. , Argan A. , Barbiellini G. , Bulgarelli A. , Burgay M. , Caraveo P. , Cattaneo P. W. , Chen A. W. , Cocco V. , Contessi T. , Costa E. , D’Ammando F. , Del Monte E. , De Paris G. , Di Cocco G. , Di Persio G. , Donnarumma I. , Evangelista Y. , Feroci M. , Ferrari A. , Fiorini M. , Fuschino F. , Galli M. , Gianotti F. , Hotan A. , Labanti C. , Lapshov I. , Lazzarotto F. , Lipari P. , Longo F. , Marisaldi M. , Mastropietro M. , Mereghetti S. , Moretti E. , Morselli A. , Pacciani L. , Palfreyman J. , Perotti F. , Picozza P. , Pittori C. , Possenti A. , Prest M. , Rapisarda M. , Rappoldi A. , Rossi E. , Rubini A. , Santolamazza P. , Scalise E. , Soffitta P. , Striani E. , Trifoglio M. , Vallazza E. , Vercellone S. , Verrecchia F. , Vittorini V. , Zambra A. , Zanello D. , Giommi P. , Colafrancesco S. , Antonelli A. , Salotti L. , D’Amico N. , Bignami G. F.
Published: January 2010

Pulsar Wind Nebula

Pulsar wind nebulae are the result of the interaction between the wind of relativistic charged particles emitted by pulsars and their surrounding interstellar medium. Using the AGILE satellite,

Pellizzoni
et al.

(p.
663
, published online 31 December) detected extended gamma-ray emission between 100 megaelectron volts and 3 gigaelectron volts from the 10,000-year-old Vela pulsar wind nebula. This detection sets constraints on the relativistic particle wind of pulsars, its energetic content, and its interactions with the surrounding medium. It also suggests that pulsar wind nebulae could form a subset of the yet unidentified galactic gamma-ray sources.
Some Enzymes Just Need a Space of Their Own
Authors: Kang Sebyung , Douglas Trevor
Published: December 2009

Protein shells that sequester enzymatic reactions are found in diverse organisms and may provide blueprints for nanoparticle design.
Rossiter H. Crozier (1943–2009)
Authors: Boomsma Jacobus J. , Pamilo Pekka
Published: December 2009

A geneticist's fascination with ants and other social insects yielded deep insights into the evolution of animal societies.
Errors in Chemistry Claims Cast Doubt on Reactome Paper
Authors: Travis John
Published: December 2009

Last week,
Science
published online an "Editorial Expression of Concern" noting that "serious questions have been raised about the methods and data presented" in the description of a newly developed research tool called a reactome array, which was published in the 9 October issue of
Science
.
Embryo Ruling Keeps Stem Cell Research Legal
Authors: Vogel Gretchen
Published: December 2009

A ruling from the Irish Supreme Court has reignited that country's debate over the legal status of human embryos, confirming the legality of research with human embryonic stem cells but leaving such work in a regulatory limbo that may not be resolved soon.
Antibacterial Activity of
N
-Pentylpantothenamide Is Due to Inhibition of Coenzyme A Synthesis
Authors: Thomas Jacob , Cronan John E.
Published: January 2010

Growth inhibition by the pantothenate analog
N
-pentylpantothenamide (N5-Pan) has been attributed to the accumulation of acyl carrier protein carrying a prosthetic group modified by incorporation of N5-Pan. This was attributed to an inability of the AcpH acyl carrier protein phosphodiesterase to cleave the N5-Pan-modified prosthetic group from the protein moiety. We report that AcpH readily removes the N5-Pan-modified prosthetic group both
in vivo
and
in vitro
and show that N5-Pan blocks coenzyme A synthesis.