bluuebunny/crossref_metadata_2025 huggingface dataset:
Maintenance of spermatogenesis requires TAF4b, a gonad-specific subunit of TFIID
Authors: Falender Allison E. , Freiman Richard N. , Geles Kenneth G. , Lo Kirk C. , Hwang KeumSil , Lamb Dolores J. , Morris Patricia L. , Tjian Robert , Richards JoAnne S.
Published: March 2005

The establishment and maintenance of spermatogenesis in mammals requires specialized networks of gene expression programs in the testis. The gonad-specific TAF4b component of TFIID (formerly TAFII105) is a transcriptional regulator enriched in the mouse testis. Herein we show that TAF4b is required for maintenance of spermatogenesis in the mouse. While youngTaf4b-null males are initially fertile,Taf4b-null males become infertile by 3 mo of age and eventually exhibit seminiferous tubules devoid of germ cells. At birth, testes ofTaf4b-null males appear histologically normal; however, at post-natal day 3 gonocyte proliferation is impaired and expression of spermatogonial stem cell markersc-Ret,Plzf, andStra8is reduced. Together, these data indicate that TAF4b is required for the precise expression of gene products essential for germ cell proliferation and suggest that TAF4b may be required for the regulation of spermatogonial stem cell specification and proliferation that is obligatory for normal spermatogenic maintenance in the adult.
Perceptions of father involvement patterns in teenage‐mother families: Predictors and links to mothers’ psychological adjustment*
Authors: Kalil Ariel , Ziol‐Guest Kathleen M. , Coley Rebekah Levine
Published: March 2005

Abstract: Based on adolescent mothers’ reports, longitudinal patterns of involvement of young, unmarried biological fathers (n = 77) in teenage‐mother families using cluster analytic techniques were examined. Approximately one third of fathers maintained high levels of involvement over time, another third demonstrated low involvement at both time points, and the final third started out highly involved at Wave 1 but decreased to low levels of involvement by Wave 2. Multinomial logistic analyses suggest that mothers’ positive relationships with both the father and his family predict a greater likelihood of initiated and sustained high father involvement. In contrast, stronger support from the maternal grandmother is related to decreasing father involvement over time, and coresidence with the grandmother is related to sustained low father involvement. Whereas a decreasing pattern of father involvement was significantly associated with increased maternal parenting stress over time, the patterns of father involvement were unrelated to changes in young mothers’ levels of depressive symptoms and mastery.
Recurrent disruptions of rituals and routines in families with paternal alcohol abuse*
Authors: Haugland Bente Storm Mowatt
Published: March 2005

Abstract: Changes in rituals and routines between drinking and sobriety were examined in families in treatment due to paternal alcohol abuse. Information was gathered through a semistructured family interview. Recurrent disruptions of rituals and routines were found between different phases in the drinking cycle. Disruptions were found typically with regard to the fathers’ participation in rituals and routines, the parental roles and responsibility, the affective quality of the rituals, and the general family climate. Four categories of families were distinguished based on amount and type of disruptions in family rituals and routines (i.e. protecting, emotional disruptive, exposing, and chaotic families). Implications for intervention are described.
Bridging research and practice in the family and human sciences*
Authors: Small Stephen A.
Published: March 2005

Abstract:Over the past decade there has been a growing concern over the gap between research and practice in family and other human sciences. Family scientists have been troubled that the scientific knowledge base is not frequently used by practitioners, whereas practitioners have complained that the research base is often not very useful for issues faced in practice. The present article examines some of the reasons for the gap between research and practice and offers some suggestions for bridging it.
Mortality of White Americans, African Americans, and Canadians: The Causes and Consequences for Health of Welfare State Institutions and Policies
Authors: KUNITZ STEPHEN J. , PESIS‐KATZ IRENA
Published: March 2005

The life expectancy of African Americans has been substantially lower than that of white Americans for as long as records are available. The life expectancy of all Americans has been lower than that of all Canadians since the beginning of the 20th century. Until the 1970s this disparity was the result of the low life expectancy of African Americans. Since then, the life expectancy of white Americans has not improved as much as that of all Canadians. This article discusses two issues: racial disparities in the United States, and the difference in life expectancy between all Canadians and white Americans. Each country's political culture and institutions have shaped these differences, especially national health insurance in Canada and its absence in the United States. The American welfare state has contributed to and explains these differences.
ON UTILITY‐BASED PRICING OF CONTINGENT CLAIMS IN INCOMPLETE MARKETS
Authors: Hugonnier Julien , Kramkov Dmitry , Schachermayer Walter
Published: March 2005

We study the uniqueness of the marginal utility‐based price of contingent claims in a semimartingale model of an incomplete financial market. In particular, we obtain that a necessary and sufficient condition for all bounded contingent claims to admit a unique marginal utility‐based price is that the solution to the dual problem defines an equivalent local martingale measure.
EVALUATING HEDGING ERRORS: AN ASYMPTOTIC APPROACH
Authors: Hayashi Takaki , Mykland Per A.
Published: March 2005

We propose a methodology for evaluating the hedging errors of derivative securities due to the discreteness of trading times or the observation times of market prices, or both. Utilizing a weak convergence approach, we derive the asymptotic distributions of the hedging errors as the discreteness disappears in several situations. First, we examine the hedging error due to discrete‐time trading when the true strategy is known, which generalizes the result of Bertsimas, Kogan, and Lo (2000) to continuous Itô processes. Then we consider a data‐driven strategy, when the true strategy is unknown. This strategy is free of parametric model assumptions, therefore it is expected to serve as a benchmark for the evaluation of parametric strategies. Finally, we consider a case study of the Black‐Scholes delta‐hedging strategy when the volatility is unknown in the proposed framework. The results obtained give us a prospect for further developments of the framework under which various parametric strategies could be compared in a unified manner.
Interaction of an insecticide with larval density in pond‐breeding salamanders (Ambystoma)
Authors: METTS BRIAN S. , HOPKINS WILLIAM A. , NESTOR JOHN P.
Published: March 2005

1. Amphibian populations residing in or near agricultural areas are often susceptible to pesticide contamination. Recent evidence suggests that the effects of pesticides on amphibians often exceed those estimated in laboratory toxicity tests because other environmental factors (e.g. predators, resource abundance) can influence pesticide toxicity.

2. To examine the effects of an insecticide (carbaryl) on two species of Ambystoma salamanders experiencing the natural stress of competition, we manipulated chemical concentration (control, 3.5 and 7.0 mg L−1) and larval density (low and high). We determined the effect of treatments on snout‐vent length (SVL), growth rate, lipid reserves, time to metamorphosis, per cent survival and per cent metamorphosis.

3. Carbaryl negatively affected all response variables of Ambystoma maculatum significantly, and significantly reduced survival and metamorphosis of A. opacum. Increased density significantly influenced SVL, lipid reserves, growth rate and metamorphosis of A. maculatum.

4. The effects of carbaryl and increased density on per cent metamorphosis were nearly additive, but were generally less than additive on other variables.

5. The negative effects of chemical contamination on salamanders were likely because of pesticide‐induced reductions of food resources, as zooplankton abundance decreased by as much as 97% following carbaryl application.

6. Our study demonstrates the importance of the interactive effects that chemical contamination and natural environmental factors have on salamanders.
Prevalence of apical periodontitis and the quality of endodontic treatment in an adult Belarusian population
Authors: Kabak Y. , Abbott P. V.
Published: March 2005

Aim  To estimate the prevalence of teeth with apical periodontitis (AP) and technically failed root fillings in an adult Belarusian population.

Methodology  Panoramic radiographs of all 1423 patients over 15 years of age not seeking emergency dental care, and attending the Dental School of the Belarusian Medical University for the first time during the period from 1 January to 31 December 2001 were examined. The quality of root fillings was scored according to criteria of length proposed by De Moor et al. [International Endodontic Journal33 (2000) 113] and the periapical status of all teeth (except third molars) was categorized on the basis of presence or absence of radiographic signs of AP. The data were analysed using the chi‐square test and odds ratio.

Results  Radiographs indicated that 8632 teeth (22% in the maxilla; 21% in the mandible) were missing leaving a total of 31 212 teeth to be assessed. Twenty per cent of the teeth had some filling material in the root canal(s). AP was found in 1141 subjects (80%) and 12% of the teeth. AP was more frequently associated with molar teeth (23%) than premolar (14%), canine (4%) and incisor teeth (6%). AP was diagnosed in 45% of root filled teeth, the remaining cases with AP had not been root filled. Statistical analysis showed that the probability of radiological detection of AP in root filled teeth was 25‐fold higher than when the root canals had not been filled (χ2 = 8636.04, P ≤ 0.001, odds ratio with 95% confidence intervals: 23.01 < 25.17 < 27.45). Periapical radiolucencies with adequately filled root canals occurred significantly less often than with teeth in which the root canal was filled more than 2 mm from radiographic apex or when filling material was extruded through the apex.

Conclusion  The prevalence of AP in all age groups in Belarus was higher than in other populations. The probability of AP increased significantly after root canal treatment and was closely correlated with the quality of the root filling.
Evaluation of a postgraduate training programme for community mental health practitioners
Authors: GAUNTLETT A. N.
Published: March 2005

Government guidelines on mental health care in England have considerable implications for the level of competency required by the mental health workforce. Implementing these changes requires the widespread introduction of training initiatives whose effectiveness in improving staff performance need to be demonstrated through programme evaluation. This exploratory study evaluates the impact of a 2‐year mental health training programme by measuring skill acquisition and skill application, by identifying the key ingredients for facilitating the transfer of learning into practice, and by examining differences in outcome between the academic and the non‐academic students. High skill acquisition and application was reported in the majority of interventions, however, low skill application was reported for some key interventions (assertive outreach, dual diagnosis). Statistically significant differences were found between student cohorts in one intervention for skill acquisition (crisis intervention) and two interventions for skill application (client strengths model; medication management). The main ingredients for facilitating transfer were found to be the credibility of the trainers and training alongside colleagues from their own workplace. Some of the possible explanatory factors for these findings are discussed.
Reasons for admission and their implications for the nature of acute inpatient psychiatric nursing
Authors: BOWERS L.
Published: March 2005

The purpose of acute inpatient psychiatric care, and nurses’ role within that, are in need of clarification and restatement in order to provide a framework for practice, education, research and development. Inpatient psychiatry has suffered from a paucity of research in recent years. In addition, being a complex system, involving multiple professions with differing ideologies, means that widely accepted succinct descriptions of its purpose are hard to achieve. Yet such a framework is essential to support positive attitudes to patients and for good staff‐management relationships. Using an oblique strategy, this paper defines the function of acute inpatient psychiatry, and the role of psychiatric nurses, via a structured examination of the literature on reasons for admission to acute inpatient psychiatric wards. Seven such reasons were discovered and are described: dangerousness, assessment, medical treatment, severe mental disorder, self‐care deficits, respite for carers, and respite for the patient. Acute inpatient psychiatric nurses are therefore: providing safety for the patient and others; collecting and communicating information about patients, giving and monitoring treatment; tolerating and managing disturbed behaviour; providing personal care; and managing an environment where patients can comfortably stay. The implications for psychiatric nursing are discussed.
Exploring the concept of recovery in schizophrenia
Authors: KELLY M. , GAMBLE C.
Published: March 2005

The concept of recovery in psychosis has gained much momentum in recent years in the UK. Current government policy describes its underpinning philosophy as the way forward for mental health services. Many mental health professionals now claim to embrace this concept yet fail to make the desired impact upon the care and treatment of individuals with schizophrenia. This article reviews some of the literature and explores what the concept of recovery means. The formal evidence will be augmented with personal accounts about recovery written by individuals who have schizophrenia. In doing so the main components that appear to have influenced the recovery process will be highlighted, and the implications for mental health nurses and practitioners will be discussed.
Occurrence of cold activation of transfusion plasma during storage at +4 °C
Authors: Suontaka A. M. , Silveira A. , Söderström T. , Blombäck M.
Published: March 2005

Background and Objectives  The storage of transfusion plasma at +4 °C sometimes leads to the activation of several proteolytic systems. In this study the frequency of cold activation was investigated, as well as whether cold activation of plasma is an individually recurrent property of the donor.

Materials and Methods  Plasma units prepared from whole blood obtained from 100 male donors were stored at +2° to +5 °C, in bags for 28 days and in cryotubes for up to 42 days. Samples from plasma units, collected by apheresis from 100 male donors, were stored in cryotubes for up to 42 days. Cold activation was measured weekly as kallikrein‐like activity of plasma. Samples from repeat apheresis plasma units from 32 donors were measured 12–20 months later. The effects of storage on the contact, coagulation and fibrinolytic systems were determined.

Results  The cumulative frequency of cold‐activated plasma units stored in bags was 5% on day 7 and 18% on day 28. After 42 days in cryotubes, 49% of the plasma units were cold activated. Large intraindividual differences in the onset‐day of cold activation were observed in plasma samples of some donors. During cold activation, an increase in kallikrein‐like activity was accompanied by a decrease in C1 esterase inhibitor activity and an increase in the concentrations of activated factor VII and fibrinopeptide A. The functional plasminogen level was unchanged, while a minor decrease in plasmin inhibitor activity was combined with a corresponding increase in the concentration of plasmin–plasmin inhibitor complex.

Conclusions  The cumulative frequency of cold‐activated plasma units increased in a time‐dependent manner during storage at +2° to +5 °C for 42 days. The intraindividual onset‐day of cold activation varied widely between plasma samples of some donors. Cold activation was associated with a high degree of activation of the contact and coagulation systems. The fibrinolytic system was scarcely affected.
Why Have Workers Stopped Joining Unions? The Rise in Never‐Membership in Britain
Authors: Bryson Alex , Gomez Rafael
Published: March 2005

This paper tracks the rise in the percentage of employees who have never become union members (‘never‐member’) since the early 1980s and shows that it is the reduced likelihood of ever becoming a member, rather than the haemorrhaging of existing members, that is behind the decline in overall union membership in Britain. We estimate the determinants of ‘never‐membership’ and consider how much of the rise can be explained by structural change in the labour market and how much by change in preferences among employees.
The relationship between the onset of electrographic seizure activity after birth and the time of cerebral injury in utero
Authors: Filan P. , Boylan G.B. , Chorley G. , Davies A. , Fox G.F. , Pressler R. , Rennie J.M.
Published: March 2005

In the fetal lamb model of hypoxic–ischaemic injury, the insult is followed by EEG depression, after which seizures emerge at 7–13 hours. We explored the relationship between the emergence of electrographic seizures and our estimate of the time of the cerebral injury in nine babies who underwent continuous video‐EEG monitoring from soon after birth. Babies with prelabour insults had their first seizures before 12 hours of age, whereas those whose insult was peripartum had seizure onset at 18–20 hours of age. EEG seizure onset time could have important clinical and medico‐legal applications, and be related to the time or severity of the insult, or both.
Cardiovascular risk at age 53 years in relation to the menopause transition and use of hormone replacement therapy: a prospective British birth cohort study
Authors: Kuh D. , Langenberg C. , Hardy R. , Kok H. , Cooper R. , Butterworth S. , Wadsworth M.E.J.
Published: March 2005

Objectives  To investigate cardiovascular risk factors and changes in risk factor levels in relation to menopausal stage, hysterectomy status and hormone replacement therapy use in a cohort of women aged 53 years with prospective data on smoking, lifetime socio‐economic circumstances, and blood pressure and obesity at age 43 years.

Design  A prospective study.

Setting  England, Scotland and Wales.

Population  A cohort of women from the Medical Research Council Survey of Health and Development.

Methods  A total of 1303 women, aged 53 years, from a UK birth cohort study with measures of cardiovascular risk factors were classified by five menopausal status groups (premenopause, perimenopause, postmenopause, hysterectomy and hormone replacement therapy user). Body mass index, glycosolated haemoglobin, blood pressure, high density lipoprotein, low density lipoprotein and total cholesterol measurements were taken, and analysed within the groups taking confounding variables into account. Changes in body mass index and blood pressure measurement in the same women obtained when 43 years of age were also compared.

Main outcome measures  Body mass index, glycosolated haemoglobin, blood pressure, high density lipoprotein, low density lipoprotein and total cholesterol.

Results  At 53 years, body mass index, waist circumference, total and low density lipoprotein cholesterol, and glycosolated haemoglobin (HbA1c) varied by menopausal status group, but blood pressure did not. Levels of total cholesterol and HbA1c increased across the natural menopause transition, before and after adjustment for body mass index, smoking and lifetime socio‐economic circumstances. After adjustment for confounders, levels of risk factors for hysterectomised women were similar to those of naturally postmenopausal women. Women on hormone replacement therapy had lower levels of total and low density lipoprotein cholesterol, HbA1c, and were less obese than postmenopausal women. The lower obesity levels were partly due to these women already being less obese at age 43 years.

Conclusions  This study showed that naturally postmenopausal or hysterectomised women had higher levels of metabolic risk factors compared with premenopausal or perimenopausal women of the same age. The long term stability of these differences and their translation into variations in incidence of cardiovascular disease remain to be seen. The lower levels of metabolic risk factors for women on hormone replacement therapy may protect against future cardiovascular disease or may be overwhelmed by other adverse, and as yet unknown, effects of hormone replacement therapy.
Effects of intense training during and after pregnancy in top‐level athletes
Authors: Kardel Kristin Reimers
Published: March 2005

This study investigates the effects of vigorous exercise during and after pregnancy in top competitive athletes. The hypothesis tested here is that training of sufficiently high volume during pregnancy can maintain initial fitness levels. A second hypothesis, that high‐volume training during pregnancy in initially fit women does not pose a health risk for the mother or the fetus, was tested and found to hold in a prior report. The overall aim of the study was to define a safe training regime for the maintenance of fitness in top‐level female athletes during pregnancy.

Forty‐one healthy athletes who had performed exercise regularly prior to conception were followed from gestational week 17 until 12 weeks postpartum while they performed standardized exercise programs. The subjects participated either in a high‐volume exercise group (HEG, n=20, 8.4 h week−1) or in a medium‐volume exercise group (MEG, n=21, 6 h week−1).

The results show that well‐trained women can benefit substantially from training at high volumes during an uncomplicated pregnancy. This can facilitate a rapid return to competitive athletics and physically active life after pregnancy. Guidelines for safe exercise by sufficiently fit women during pregnancy could be modeled on the high‐volume exercise regime used here by the HEG.
Effects of caffeine ingestion on rating of perceived exertion during and after exercise: a meta‐analysis
Authors: Doherty M. , Smith P. M.
Published: March 2005

The purpose of this study was to use the meta‐analytic approach to examine the effects of caffeine ingestion on ratings of perceived exertion (RPE). Twenty‐one studies with 109 effect sizes (ESs) met the inclusion criteria. Coding incorporated RPE scores obtained both during constant load exercise (n=89) and upon termination of exhausting exercise (n=20). In addition, when reported, the exercise performance ES was also computed (n=16). In comparison to placebo, caffeine reduced RPE during exercise by 5.6% (95% CI (confidence interval), −4.5% to −6.7%), with an equivalent RPE ES of −0.47 (95% CI, −0.35 to −0.59). These values were significantly greater (P<0.05) than RPE obtained at the end of exercise (RPE % change, 0.01%; 95% CI, −1.9 to 2.0%; RPE ES, 0.00, 95% CI, −0.17 to 0.17). In addition, caffeine improved exercise performance by 11.2% (95% CI; 4.6–17.8%). Regression analysis revealed that RPE obtained during exercise could account for ∼29% of the variance in the improvement in exercise performance. The results demonstrate that caffeine reduces RPE during exercise and this may partly explain the subsequent ergogenic effects of caffeine on performance.
A prospective analysis of incidence and severity of quadriceps inhibition in a consecutive sample of 100 patients with complete acute anterior cruciate ligament rupture
Authors: Chmielewski T. L. , Stackhouse S. , Axe M. J. , Snyder‐Mackler L.
Published: March 2005

Background: Weakness of the quadriceps femoris muscle after anterior cruciate ligament (ACL) injury and reconstruction has been attributed to incomplete voluntary activation of the muscle. The literature is conflicting on the incidence of incomplete voluntary quadriceps activation after ACL injury because of differences in testing methods and population biases. The purpose of this study was to systematically examine the incidence and severity of quadriceps voluntary activation failure in both lower extremities after acute ACL injury. We hypothesized that the incidence of quadriceps inhibition would be higher in the ACL‐injured limbs than the uninvolved limbs, that the incidence of inhibition in the ACL‐deficient limbs would be larger than in our historical sample of healthy young individuals tested in the same manner and that there would be no difference in inhibition by gender.

Study Design: Prospective, descriptive.

Methods: One hundred consecutive patients with acute ACL rupture (39 women and 61 men) were tested when range of motion was restored and effusion resolved, an average of 6 weeks after injury. A burst superimposition technique was used to assess quadriceps muscle activation and strength in all patients. Dependent t‐tests were used to compare side‐to‐side differences in quadriceps strength. Independent t‐tests were used to compare incidence of activation failure by gender and make comparisons to historical data on young, active individuals.

Results: The average involved side quadriceps activation was 0.92, and ranged from 0.60 to 1.00. The incidence of incomplete activation in the involved side quadriceps was 33 percent and in the uninvolved side quadriceps was 31 percent after acute ACL rupture. The incidence of incomplete activation bilaterally was 21 percent. There was no difference in incidence of quadriceps inhibition by gender.

Conclusion: The incidence of voluntary quadriceps inhibition on the involved side was three times that of uninjured, active young subjects, but the magnitude was not large. The incidence of quadriceps inhibition on the uninjured side was similar to the injured side.

Clinical relevance: Both the incidence and magnitude of quadriceps inhibition after ACL rupture are lower than have previously been reported. The conventional wisdom, therefore, that quadriceps inhibition is a significant problem in this population is challenged by the results of this study. Differences between this study and others include sufficient practice to ensure a maximal effort contraction and rigorous inclusion criteria. The findings have implications for strength testing as well as rehabilitation. The quadriceps index, an assessment of the injured side quadriceps strength deficit, may be affected by the presence of voluntary activation failure in the uninvolved side.
The effects of microgravity on the development of surface righting in rats
Authors: Walton Kerry D. , Harding Shannon , Anschel David , Harris Ya'el Tobi , Llinás Rodolfo
Published: March 2005

The active interaction of neonatal animals with their environment has been shown to be a decisive factor in the postnatal development of sensory systems, which demonstrates a critical period in their maturation. The direct demonstration of such a dependence on the rearing environment has not been demonstrated for motor system function. Nor has the role of gravity in mammalian motor system development been investigated. Here we report the results of two space flight missions examining the effect of removing gravity on the development of surface righting. Since the essential stimulus that drives this synergy, gravitation, was missing, righting did not occur while the animals were in the microgravity environment. We hypothesize that this absence of contextual motor experience arrested the maturation of the motor tactics for surface righting. Such effects were permanent in rats spending 16 days (from postnatal day (P), P14 to P30), but were transient in animals spending nine days (from P15 to P24) in microgravity. Thus, active, contextual interaction with the environment during a critical period of development is necessary for the postnatal maturation of motor tactics as exemplified by surface righting, and such events must occur within a particular time period. Further, Earth's gravitational field is not assumed by the developing motor system. Rather, postnatal motor system development is appropriate to the gravitational field in which the animal is reared.
Investigating the causes of low birth weight in contrasting ovine paradigms
Authors: Wallace J. M. , Regnault T. R. H. , Limesand S. W. , Hay W. W. , Anthony R. V.
Published: March 2005

Intrauterine growth restriction (IUGR) still accounts for a large incidence of infant mortality and morbity worldwide. Many of the circulatory and transport properties of the sheep placenta are similar to those of the human placenta and as such, the pregnant sheep offers an excellent model in which to study the development of IUGR. Two natural models of ovine IUGR are those of hyperthermic exposure during pregnancy, and adolescent overfeeding, also during pregnancy. Both models yield significantly reduced placental weights and an asymmetrically growth‐restricted fetus, and display altered maternal hormone concentrations, indicative of an impaired trophoblast capacity. Additionally, impaired placental angiogenesis and uteroplacental blood flow appears to be an early defect in both the hyperthermic and adolescent paradigms. The effects of these alterations in placental functional development appear to be irreversible. IUGR fetuses are both hypoxic and hypoglycaemic, and have reduced insulin and insulin‐like growth factor‐1 (IGF‐1), and elevated concentrations of lactate. However, fetal utilization of oxygen and glucose, on a weight basis, remain constant compared with control pregnancies. Maintained utilization of these substrates, in a substrate‐deficient environment, suggests increased sensitivities to metabolic signals, which may play a role in the development of metabolic diseases in later adult life.
Crossbridge properties investigated by fast ramp stretching of activated frog muscle fibres
Authors: Bagni M. Angela , Cecchi Giovanni , Colombini Barbara
Published: March 2005

Very fast ramp stretches at 9.5–33 sarcomere lengths s−1 (l0s−1) stretching speed, 16–25 nm per half‐sarcomere (nm hs−1) amplitude were applied to activated intact frog muscle fibres at tetanus plateau, during the tetanus rise, during the isometric phase of relaxation and during isotonic shortening. Stretches produced an almost linear tension increase above the isometric level up to a peak, and fell to a lower value in spite of continued stretching, indicating that the fibre became suddenly very compliant. This suggests that peak tension (critical tension, Pc) represents the tension at which crossbridges are forcibly detached by the stretch. The ratio of Pc to the isometric tension at tetanus plateau (P0) was 2.37 ± 0.12 (s.e.m.). This ratio did not change significantly at lower tension (P) during the tetanus rise but decreased with time during the relaxation and increased with speed during isotonic shortening. At tetanus plateau Pc occurred when sarcomere elongation attained a critical length (Lc) of 10.98 ± 0.13 nm hs−1, independently of the stretching speed. Lc remained constant during the tetanus rise but decreased on the relaxation and increased during isotonic shortening. Length‐clamp experiments on the relaxation showed that the lower values of Pc/P ratio and Lc, were both due to the slow sarcomere stretching occurring during this phase. Our data show that Pc can be used as a measure of crossbridge number, while Lc is a measure of crossbridge mean extension. Accordingly, for a given tension, crossbridges on the isometric relaxation are fewer than during the rise, develop a greater individual force and have a greater mean extension, while during isotonic shortening crossbridges are in a greater number but develop a smaller individual force and have a smaller extension.
Extrusion and Death of DPP/BMP-Compromised Epithelial Cells in the Developing
Drosophila
Wing
Authors: Gibson Matthew C. , Perrimon Norbert
Published: March 2005

During animal development, epithelial cell fates are specified according to spatial position by extracellular signaling pathways. Among these, the transforming growth factor β/bone morphogenetic protein (TGF-β/BMP) pathways are evolutionarily conserved and play crucial roles in the development and homeostasis of a wide range of multicellular tissues. Here we show that in the developing
Drosophila
wing imaginal epithelium, cell clones deprived of the BMP-like ligand Decapentaplegic (DPP) do not die as previously thought but rather extrude from the cell layer as viable cysts exhibiting marked abnormalities in cell shape and cytoskeletal organization. We propose that in addition to assigning cell fates, a crucial developmental function of DPP/BMP signaling is the position-specific control of epithelial architecture.
Self-Organized Origami
Authors: Mahadevan L. , Rica S.
Published: March 2005

In origami, form follows the sequential spatial organization of folds. This requires continuous intervention and raises a natural question: Can origami arise through self-organization? We answer this affirmatively by examining the possible physical origin for the Miura-ori leaf-folding patterns that arise naturally in insect wings, leaves, and other laminae-like organelles. In particular, we point out examples where biaxial compression of an elastically supported thin film, such as that due to differential growth, shrinkage, desiccation, or thermal expansion, spontaneously generates these patterns, and we provide a simple theoretical explanation for their occurrence.
Assessing Methane Emissions from Global Space-Borne Observations
Authors: Frankenberg C. , Meirink J. F. , van Weele M. , Platt U. , Wagner T.
Published: March 2005

In the past two centuries, atmospheric methane has more than doubled and now constitutes 20% of the anthropogenic climate forcing by greenhouse gases. Yet its sources are not well quantified, introducing uncertainties in its global budget. We retrieved the global methane distribution by using spaceborne near-infrared absorption spectroscopy. In addition to the expected latitudinal gradient, we detected large-scale patterns of anthropogenic and natural methane emissions. Furthermore, we observed unexpectedly high methane concentrations over tropical rainforests, revealing that emission inventories considerably underestimated methane sources in these regions during the time period of investigation (August through November 2003).
Nicotinic Acid Limitation Regulates Silencing of
Candida
Adhesins During UTI
Authors: Domergue Renee , Castaño Irene , De Las Peñas Alejandro , Zupancic Margaret , Lockatell Virginia , Hebel J. Richard , Johnson David , Cormack Brendan P.
Published: March 2005

The adherence of
Candida glabrata
to host cells is mediated, at least in part, by the
EPA
genes, a family of adhesins encoded at subtelomeric loci, where they are subject to transcriptional silencing. We show that normally silent
EPA
genes are expressed during murine urinary tract infection (UTI) and that the inducing signal is the limitation of nicotinic acid (NA), a precursor of nicotinamide adenine dinucleotide (NAD
+
).
C. glabrata
is an NA auxotroph, and NA-induced
EPA
expression is likely the result of a reduction in NAD
+
availability for the NAD
+
-dependent histone deacetylase Sir2p. The adaptation of
C. glabrata
to the host, therefore, involves a loss of metabolic capacity and exploitation of the resulting auxotrophy to signal a particular host environment.
OVERLAYING SURFACE MESHES, PART I: ALGORITHMS
Authors: JIAO XIANGMIN , HEATH MICHAEL T.
Published: March 2005

We describe an efficient and robust algorithm for computing a common refinement of two meshes modeling the same surface of arbitrary shape by overlaying them on top of each other. A common refinement is an important data structure for transferring data between meshes that have different combinatorial structures. Our algorithm is optimal in time and space, with linear complexity, and is robust even with inexact computations, through the techniques of error analysis, detection of topological inconsistencies, and automatic resolution of such inconsistencies. We present the verification and some further enhancement of robustness in Part II.
DNA MISMATCH REPAIR
Authors: Kunkel Thomas A. , Erie Dorothy A.
Published: March 2005

▪ Abstract  DNA mismatch repair (MMR) is an evolutionarily conserved process that corrects mismatches generated during DNA replication and escape proofreading. MMR proteins also participate in many other DNA transactions, such that inactivation of MMR can have wide-ranging biological consequences, which can be either beneficial or detrimental. We begin this review by briefly considering the multiple functions of MMR proteins and the consequences of impaired function. We then focus on the biochemical mechanism of MMR replication errors. Emphasis is on structure-function studies of MMR proteins, on how mismatches are recognized, on the process by which the newly replicated strand is identified, and on excision of the replication error.
Retinal Prosthesis
Authors: Weiland James D. , Liu Wentai , Humayun Mark S.
Published: March 2005

▪ Abstract  Retinal prostheses represent the best near-term hope for individuals with incurable, blinding diseases of the outer retina. On the basis of the electrical activation of nerves, prototype retinal prostheses have been tested in blind humans and have demonstrated the capability to elicit the sensation of light and to give test subjects the ability to detect motion. To improve the visual function in implant recipients, a more sophisticated device is required. Simulations suggest that 600–1000 pixels will be required to provide visual function such as face recognition and reading. State-of-the-art implantable stimulator technology cannot produce such a device, which mandates the advancement of the state of the art in areas such as analog microelectronics, wireless power and data transfer, packaging, and stimulating electrodes.
ENGINEERED POROUS CATALYTIC MATERIALS
Authors: Schüth Ferdi
Published: March 2005

▪ Abstract  In recent years substantial progress has been made in the control of the properties of porous materials on the nano-, meso-, and macroscale. The feature of solids can, in favorable cases, be tailored to such an extent that one is justified in using the term engineering of porous catalytic materials. This review highlights recent developments concerning (a) the control of the pore structure of zeolites, (b) the creation of single site type catalysts based on ordered mesoporous oxides, (c) the catalytic potential of porous coordination compounds, and (d) the advances with respect to direct production of desired shapes of porous catalytic materials.
Regulation of Secondary Metabolism in Filamentous Fungi
Authors: Yu Jae-Hyuk , Keller Nancy
Published: March 2005

Fungal secondary metabolites are of intense interest to humankind due to their pharmaceutical (antibiotics) and/or toxic (mycotoxins) properties. In the past decade, tremendous progress has been made in understanding the genes that are associated with production of various fungal secondary metabolites. Moreover, the regulatory mechanisms controlling biosynthesis of diverse groups of secondary metabolites have been unveiled. In this review, we present the current understanding of the genetic regulation of secondary metabolism from clustering of biosynthetic genes to global regulators balancing growth, sporulation, and secondary metabolite production in selected fungi with emphasis on regulation of metabolites of agricultural concern. Particularly, the roles of G protein signaling components and developmental regulators in the mycotoxin sterigmatocystin biosynthesis in the model fungus Aspergillus nidulans are discussed in depth.
Changes in rat soleus muscle phenotype consecutive to a growth in hypergravity followed by normogravity
Authors: Picquet F. , Bouet V. , Cochon L. , Lacour M. , Falempin M.
Published: March 2005

It has been demonstrated that a long-term stay in hypergravity (HG: 2G) modified the phenotype and the contractile properties of rat soleus muscle. The ability of this muscle to contract was drastically reduced, which is a sign of anticipated aging. Consequently, our aim was to determine whether rats conceived, born, and reared in hypergravity showed adaptative capacities in normogravity (NG: 1G). This study was performed on rats divided into two series: the first was reared in HG until 100 days and was submitted to normogravity until 115 to 220 postnatal days (HG-NG rats); the second was made up of age paired groups reared in normogravity (NG rats). The contractile, morphological, and phenotypical properties of soleus muscle were studied. Our results showed that the NG rats were characterized by coexpressions of slow and fast myosin, respectively, 76.5 and 23.5% at 115 days. During their postnatal maturation, the fast isoform was gradually replaced by slow myosin. At 220 days, the relative proportions were respectively 91.05% and 8.95%. From 115 to 220 days, the HG-NG rats expressed 100% of slow myosin isoform and they presented a slower contractile behavior compared with their age-matched groups; at 115 days, the whole muscle contraction time was increased by 35%, and by 15%, at 220 days. Our study underlined the importance of gravity in the muscular development and suggested the existence of critical periods in muscle phenotype installation.
Effectiveness of Sonohysterography in Infertile Patient Work-Up: A Comparison with Transvaginal Ultrasonography and Hysteroscopy
Authors: Ragni Guido , Diaferia Domenico , Vegetti Walter , Colombo Michela , Arnoldi Mariangela , Crosignani Pier Giorgio
Published: March 2005

Objective: The aim of this comparative study was to evaluate the accuracy of transvaginal ultrasonography (TVU), sonohysterography (SHG) with sterile saline solution compared to hysteroscopy in the diagnosis of intrauterine pathology in a population of infertile patients before an in vitro fertilization (IVF) program. Patients/Methods: 98 infertile patients with a mean age of 33.9 years (range 27–41) underwent TVU assessment and SHG with sterile saline solution immediately followed by hysteroscopy. Results: The clinical findings obtained by TVU, SHG and hysteroscopy were compared. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of TVU and SHG compared to hysteroscopy were calculated. The TVU sensitivity and specificity compared with hysteroscopy were 91 and 83% respectively. Using TVU, a 9.2% false positive rate (9 cases) and a 5.1% false negative rate (5 cases) were detected compared to hysteroscopy. The TVU PPV and NPV were 85.4 and 90% respectively. SHG yielded better results: sensitivity and specificity when compared to hysteroscopy were 98 and 94% respectively. The SHG PPV and NPV were 95 and 98% respectively. Accuracy of SHG was significantly better than TVU considering all intrauterine pathologies and polyps. Conclusion: In experienced hands, SHG is an easy, safe, and well-tolerated alternative to diagnostic hysteroscopy in the initial evaluation of uterine cavity infertile patients.
The Characterization of Tumor Apoptosis after Experimental Radiosurgery
Authors: Witham Timothy F. , Okada Hideho , Fellows Wendy , Hamilton Ronald L. , Flickinger John C. , Chambers William H. , Pollack Ian F. , Watkins Simon C. , Kondziolka Douglas
Published: March 2005

We sought to evaluate whether radiosurgery induces apoptosis in an experimental glioma model and to elucidate the time course of this radiobiologic phenomenon. Fischer 344 rats harboring established intracranial 9L gliosarcomas underwent radiosurgery (n = 42) or no radiosurgery (n = 45). Animals were sacrificed at 3, 6, 12, 24, 48, 72 h, and 1 or 2 weeks after treatment and in situ tumor apoptosis was assessed by specific staining. Tumor apoptosis was noted to be statistically higher in radiosurgery-treated animals relative to controls at the 6-, 24-, and 48-hour time points following radiosurgery. Radiosurgery induces apoptosis in the rat intracranial 9L gliosarcoma in a time-dependent fashion. The time course of this radiobiologic phenomenon begins at approximately 6 h following radiosurgery, continues up to 48 h, and begins to decline by 72 h.
The Association between Psychiatric and Cognitive Symptoms after Stroke: A Prospective Study
Authors: Rasquin Sascha , Lodder Jan , Verhey Frans
Published: March 2005

Background: Stroke patients often have neuropsychiatric symptoms and cognitive deficits. The aim of this study was to investigate whether stroke patients with psychiatric symptoms are at increased risk of developing cognitive deficits. Methods: Cognitive function (assessed with a neuropsychological test battery) and presence of psychiatric symptoms (assessed with the 90-item Symptom Checklist) were evaluated at 1, 6, 12 and 24 months after stroke. Results: At baseline, 156 patients entered the study, 15 had a diagnosis of vascular dementia, 113 one of post-stroke mild cognitive impairment. Patients with psychiatric symptoms were found to be at increased risk of being diagnosed as having vascular dementia at baseline (OR = 6.9, CI = 1.3–36.8) and showed more decline on cognitive function 6 months after stroke. Conclusions: Patients with psychiatric symptoms after stroke are at increased risk of cognitive deficits and decline in cognitive functioning.
The Well-Being and Personal Wellness Promotion Strategies of Medical Oncologists in the North Central Cancer Treatment Group
Authors: Shanafelt Tait D. , Novotny Paul , Johnson Mary E. , Zhao Xinghua , Steensma David P. , Lacy Martha Q. , Rubin Joseph , Sloan Jeff
Published: March 2005

Purpose: The well-being of oncologists is important to the well-being of their patients. While much is known about oncologist distress, little is known about oncologist well-being. We set out to evaluate oncologist well-being and the personal wellness promotion strategies used by oncologists. Patients and Methods: We performed a cross-sectional survey of medical oncologists in the North Central Cancer Treatment Group using a validated instrument to measure quality of life. Study-specific questions explored stressors, wellness promotion strategies and career satisfaction. Results: Of 241 responding oncologists (response rate 61%), 121 (50%) reported high overall well-being. Being age 50 or younger (57 vs. 41%; p = 0.01), male (53 vs. 31%; p = 0.01) and working 60 h or less per week (50 vs. 33%; p = 0.005) were associated with increased overall well-being on bivariate analysis. Ratings of the importance of a number of personal wellness promotion strategies differed for oncologists with high well-being compared with those without high well-being. Developing an approach/philosophy to dealing with death and end-of-life care, using recreation/hobbies/exercise, taking a positive outlook and incorporating a philosophy of balance between personal and professional life were all rated as substantially more important wellness strategies by oncologists with high well-being (p values <0.001). Oncologists with high overall well-being also reported greater career satisfaction. Conclusion: Half of medical oncologists experience high overall well-being. Use of specific personal wellness promotion strategies appears to be associated with oncologist well-being. Further investigations of the prevalence, promotion, causes, inequities and clinical impact of physician well-being are needed.