bluuebunny/crossref_metadata_2025 huggingface dataset:
Two distinct human POM121 genes: Requirement for the formation of nuclear pore complexes
Authors: Funakoshi Tomoko , Maeshima Kazuhiro , Yahata Kazuhide , Sugano Sumio , Imamoto Fumio , Imamoto Naoko
Published: September 2007

Pom121 is one of the integral membrane components of the nuclear pore complex (NPC) in vertebrate cells. Unlike rodent cells carrying a single POM121 gene, human cells possess multiple POM121 gene loci on chromosome 7q11.23, as a consequence of complex segmental‐duplications in this region during human evolution. In HeLa cells, two “full‐length” Pom121 are transcribed and translated by two distinct genetic loci. RNAi experiments showed that efficient depletion of both Pom121 proteins significantly reduces assembled NPCs on nuclear envelope. Pom121‐depletion also induced clustering of NPCs, indicating its role on maintenance of NPC structure/organization.
Oncogenic c‐H‐ras deregulates survivin expression: An improvement for survival
Authors: Sommer Klaus W. , Rodgarkia-Dara Chantal J. , Schreiner Claudia , Holzmann Klaus , Krupitza Georg , Cerni Christa
Published: September 2007

Survivin protein accomplishes two basic functions: cell cycle regulation and control of apoptosis. It is only expressed in G2/M phase and it influences rescue pathways in apoptosis‐induced cells. Overexpression of constitutive active c‐H‐ras in HeLa, or induction of c‐H‐ras in a stable HeLaDiR cell line, led to sustained survivin expression in all cell cycle phases and even protected cells from drug induced apoptosis. siRNA‐mediated silencing of survivin reversed this protection. Here we link the anti‐apoptotic property of survivin to its cell cycle (in)dependent regulation via the activity of oncogenic c‐H‐ras.
Cardiofemoral index as an ultrasound marker of fetal anemia in isoimmunized pregnancy
Authors: Cabral A.C.V. , Reis Z.S.N. , Leite H.V. , Lage E.M. , Ferreira A.L.P. , Melo I.G.
Published: September 2007

Objective

To test a new noninvasive ultrasound method for diagnosing fetal anemia in red blood cell isoimmunized pregnancies.

Methods

A diagnostic accuracy study was carried out to determine the cutoff point of an ultrasound measurement, the cardiofemoral index (CFI), calculated using the biventricular outer dimension (BVOD) and femur length to diagnosis severe anemia. The CFI measurement was performed before each of the 336 cordocenteses on 131 fetuses. Diagnosis test analysis and receiver–operating characteristics (ROC) curves were used and the area under the curve (AUC) was calculated to compare the overall accuracy of the CFI for anemia diagnosis, between fetuses with or without previous intrauterine transfusions (IUT).

Results

At first cordocentesis (n = 131) the AUC was 0.75 (95% CI, 0.66–0.84). For cases where fetuses had undergone 1 previous transfusion (n = 88) the AUC was 0.76 (95% CI, 0.64–0.88) and at the time of the third cordocentesis for IUT (n = 53) it was 0.73 (95% CI, 0.59–0.86). For a 0.59 CFI threshold to diagnosis fetuses with hemoglobin deficit above 5 g/dL, sensitivity values were 87.2%, 88.0%, and 94.1% respectively for fetuses without IUT, with 1 IUT, and with 2 IUTs. Likelihood ratios for positive (LR+) and negative (LR−) test results were 1.98, 2.05, 1.69 and 0.23, 0.21, 0.13 respectively.

Conclusion

The cardiofemoral index may be an effective noninvasive marker of severe fetal anemia in high‐risk fetuses, with accuracy similar for fetuses either with or without previous transfusions.
Morbidity in the first year postpartum among HIV‐infected women in Kenya
Authors: Chersich M.F. , Luchters S.M. , Yard E. , Othigo J.M. , Kley N. , Temmerman M.
Published: September 2007

Objective: To assess the effects of HIV infection on morbidity and the needs of infected women for services in the first year postpartum. Methods: A cross‐sectional study with 500 women attending a child‐health clinic in Mombasa, Kenya. Results: Postpartum duration was a median of 3.3 months (interquartile range, 1.9–6.1 months). The 54 HIV‐infected women had a lower income and less financial support than the uninfected women, and they were more likely to experience fever, dyspnea, and dysuria, and to have genital warts (odds ratio [OR], 9.6; 95% confidence interval [CI], 2.6–35.6; P < 0.001), candidiasis (OR, 2.9; 95% CI, 1.2–6.8; P = 0.012), and bacterial vaginosis (OR, 1.8; 95% CI, 0.95–3.3; P = 0.066). Six (nearly 15%) of the HIV‐infected women had low‐ or high‐grade squamous intraepithelial lesions, and 21 (42%) had an unmet need for contraception. More than half of all women were anemic, and normocytic anemia was predominant among the HIV infected. Conclusion: Compared with uninfected women, morbidity was increased for HIV‐infected women during the year following delivery. This period could be used to offer these, and all‐women, family planning services, cervical cancer screening, and treatment for anemia and reproductive tract infections.
Infracoccygeal sacropexy or sacrospinous suspension for uterine or vaginal vault prolapse
Authors: de Tayrac R. , Mathé M.‐L. , Bader G. , Deffieux X. , Fazel A. , Fernandez H.
Published: September 2007

Objective

To compare infracoccygeal sacropexy (IS) and sacrospinous suspension (SS) for the treatment of uterine or vault prolapse.

Methods

A randomized trial of 49 women assigned to either the IS group using IVS tape (n = 24) or SS group (n = 25). Concomitant hysterectomy and repairs were performed as appropriate. Evaluations included prolapse staging using the POP‐Q system and validated questionnaires for symptoms (PFDI), quality of life (PFIQ), and sexuality (PISQ‐12). The primary outcome measure was postoperative pain.

Results

Patients' characteristics were similar in both groups. IS was quicker, easier, and less painful than SS (P < 0.01). Hemorrhage or hematoma rates were similar. Neither rectal injury nor vaginal erosion occurred. Mean follow‐up was 16.8 months. Prolapse cure rates, symptom scores, and quality of life were similar. Postoperative cystocele occurred in 4.8% of women after IS and 25% after SS (P > 0.05).

Conclusion

Infracoccygeal sacropexy is equivalent to sacrospinous suspension, with a decreased rate of postoperative pain and cystocele recurrence.
Reconstructing the migration patterns of late Pleistocene mammals from northern Florida, USA
Authors: Hoppe Kathryn A. , Koch Paul L.
Published: September 2007

We used analyses of the strontium isotope (87Sr/86Sr) ratios of tooth enamel to reconstruct the migration patterns of fossil mammals collected along the Aucilla River in northern Florida. Specimens date to the late-glacial period and before the last glacial maximum (pre-LGM). Deer and tapir displayed low 87Sr/86Sr ratios that were similar to the ratios of Florida environments, which suggest that these taxa did not migrate long distance outside of the Florida region. Mastodons, mammoths, and equids all displayed a wide range of 87Sr/86Sr ratios. Some individuals in each taxon displayed low 87Sr/86Sr ratios that suggest they ranged locally, while other animals had high 87Sr/86Sr ratios that suggest they migrated long distances (> 150 km) outside of the Florida region. Mastodons were the only taxa from this region that provided enough well-dated specimens to compare changes in migration patterns over time. Pre-LGM mastodons displayed significantly lower 87Sr/86Sr ratios than late-glacial mastodons, which suggests that late-glacial mastodons from Florida migrated longer distances than their earlier counterparts. This change in movement patterns reflects temporal changes in regional vegetation patterns.
Learning pitch patterns in lexical identification by native English-speaking adults
Authors: WONG PATRICK C. M. , PERRACHIONE TYLER K.
Published: September 2007

The current study investigates the learning of nonnative suprasegmental patterns for word identification. Native English-speaking adults learned to use suprasegmentals (pitch patterns) to identify a vocabulary of six English pseudosyllables superimposed with three pitch patterns (18 words). Successful learning of the vocabulary necessarily entailed learning to use pitch patterns in words. Two major facets of sound-to-word learning were investigated: could native speakers of a nontone language learn the use of pitch patterns for lexical identification, and what effect did more basic auditory ability have on learning success. We found that all subjects improved to a certain degree, although large individual differences were observed. Learning success was found to be associated with the learners' ability to perceive pitch patterns in a nonlexical context and their previous musical experience. These results suggest the importance of a phonetic–phonological–lexical continuity in adult nonnative word learning, including phonological awareness and general auditory ability.
Syntactic awareness and reading ability: Is there any evidence for a special relationship?
Authors: CAIN KATE
Published: September 2007

Syntactic awareness has been linked to word reading and reading comprehension. The predictive power of two syntactic awareness tasks (grammatical correction, word-order correction) for both aspects of reading was explored in 8- and 10-year-olds. The relative contributions of vocabulary, grammatical knowledge, and memory to each were assessed. After vocabulary, memory explained variance on the word-order correction task; in contrast, grammatical knowledge explained performance on the grammatical correction task. The relation between syntactic awareness and reading comprehension was mediated by vocabulary, grammatical knowledge, and memory; in contrast, word reading and syntactic awareness shared unique variance not explained by these controls. The implications for how we measure syntactic awareness and its relation with reading ability are discussed.
Stability of Two-Dimensional Blind Grasping under the Gravity Effect and Rolling Constraints
Authors: Arimoto S. , Yoshida M. , Bae J.-H.
Published: September 2007

This paper aims to show a sensory-motor coordination control scheme that realizes stable pinching of rigid objects with parallel or nonparallel flat surfaces movable in 2-dimensional vertical plane by a pair of robot fingers with hemispherical ends. The proposed control signal is composed of gravity compensation for fingers, damping shaping, exertion of forces to the object from opposite directions, generation of moments for balancing of rotational moments, and regressors for estimating unknown steady-state terms, all of which neither need the knowledge of object parameters nor use any object sensing data. In other words, stable grasping can be realized by using only finger-joint sensing in a blind manner without using force sensors or tactile sensing. Stability of pinching motion with convergence to the state of force/torque balance is shown through computer simulations and is also proved theoretically.
New Hope for Corporate Governance in China?
Authors: Feinerman James V.
Published: September 2007

China's recent revisions to its Company Law and Securities Law have brought new attention to issues of corporate governance in Chinese companies and financial markets. Among the chief criticisms of the earlier laws – in both their provisions and application – were the lack of protection for minority shareholders, the paucity of independent directors, the absence of transparency and inadequate financial disclosure. The acknowledged need for greater congruence between Chinese law and practice and that of countries with more developed capital markets led to the proposal of amendments to China's legislation during the first half of this decade. This article highlights several improvements resulting from the revisions as well as remaining weaknesses in the regulatory framework for corporate enterprises in China.
Commentary on “Transforming Family Law in Post-Deng China”
Authors: Hualing Fu
Published: September 2007

Michael Palmer's article examines the development of three important aspects in Chinese family law: divorce, adoption and family planning. It is a commendable effort to approach Chinese family law broadly in order to bring family planning policy within its study. There remains a glaring gap in Chinese legal scholarship between the study of family law and the study of population. The disciplines are divided into two camps with little cross-fertilization. Palmer's article clearly demonstrates the importance and necessity of including family planning within the study of family law. The article is also a laudable attempt to examine the dynamic interaction between family law and socioeconomic changes.
Influenza A and respiratory syncytial virus hospital burden in young children in East London
Authors: AJAYI-OBE E. K. , COEN P. G. , HANDA R. , HAWRAMI K. , AITKEN C. , McINTOSH E. D. G. , BOOY R.
Published: September 2007

Epidemiological studies have demonstrated high hospitalization rates attributable to influenza and RSV in children aged <24 months. We prospectively recruited 977 children, aged <6 years, presenting with influenza-like illnesses at a hospital during two winter seasons between 2002 and 2004. Nasopharyngeal aspirates were performed and sent for viral immunofluorescence and PCR. Influenza and respiratory syncytial virus (RSV) rates were stratified by age, in-patient/outpatient status and clinical diagnosis. The influenza A and RSV hospitalization incidence rates were 4 and 11/10 000 person-months respectively, whereas the accident and emergency (A&E) outpatient rates were both 32/10 000 person-months in those aged <6 years. The influenza A and RSV hospitalization rates were highest in children aged <24 months and <12 months (9·1 and 35·7/10 000 person-months) respectively. Infection rates were particularly high in those aged <6 months for both viruses. The age-specific influenza A and RSV A&E admission rates were highest in those aged >6 months and those aged <12 months, respectively (43 and 92·5/10 000 person-months, respectively). In conclusion, these high paediatric RSV and influenza incidence rates can be used to inform UK policy on childhood influenza immunization and subsequent RSV immunization in the future.
Response properties of a unique subtype of wide-field amacrine cell in the rabbit retina
Authors: BLOOMFIELD STEWART A. , VÖLGYI BÉLA
Published: September 2007

We studied the morphology and physiology of a unique wide-field amacrine cell in the rabbit retina. These cells displayed a stereotypic dendritic morphology consisting of a large, circular and monostratified arbor that often extended over 2 mm. Their responses contained both somatic and dendritic sodium spikes suggesting active propagation of synaptic signals within the dendritic arbor. This idea is supported by the enormous size of their ON-OFF receptive fields. Interestingly, these cells exhibited separate ON and OFF receptive fields that, while concentric, were vastly different in size. Whereas the ON receptive field of these cells extended nearly 2 mm, the OFF receptive field was typically 75% smaller. Blockade of voltage-gated sodium channels with QX-314 dramatically reduced the large ON receptive field, but had little effect on the smaller OFF receptive field. These results indicate a spatial disparity in the location of on- and off-center bipolar cell inputs to the dendritic arbor of wide-field amacrine cells. In addition, the active propagation of signals suggests that synaptic inputs are integrated both locally and globally within the dendritic arbor.
War in the Fields and Villages: The County War Agricultural Committees in England, 1939–45
Authors: SHORT BRIAN
Published: September 2007

State intervention in the United Kingdom's farming industry was necessitated by the problems of the interwar depression and the lead up to World War Two and the emergency wartime food programme. This brought the need for greater bureaucratic machinery which would connect individual farmers and their communities with central government. Crucial from 1939 in this respect was the formation of the County War Agricultural Executive Committees, which became the channels through which English farming was propelled into postwar productivism. Using relatively newly-available documentary material, this article demonstrates the role the committees played in the transmission of national policies down to the local level, their composition and membership. In so doing it also places the economic changes within farming into the vital but under-researched context of their rural social relations during the Second World War.
Regulation and Response: Kansas Wheat Farmers and the New Deal
Authors: FEARON PETER
Published: September 2007

This paper analyses the response of Kansas wheat growers to major market intervention brought about by New Deal farm policies. Congress hoped to trigger a sharp price increase by persuading farmers to reduce the acreage on which they cultivated wheat. However, the actual responses in terms of planting strategies and farm machinery purchases are complex and only evident once the analysis is conducted at the county level. Marked regional variations in the impact of the weather during the ‘Dust Bowl’ decade also played a crucial role in this analysis. This article shows that even when considering a crop grown in a single state, the reaction of farmers to policy initatives can be varied and very difficult to predict.
Lower Bounds for Partial Matchings in Regular Bipartite Graphs and Applications to the Monomer–Dimer Entropy
Authors: FRIEDLAND SHMUEL , GURVITS LEONID
Published: September 2007

We derive here the Friedland–Tverberg inequality for positive hyperbolic polynomials. This inequality is applied to give lower bounds for the number of matchings in r-regular bipartite graphs. It is shown that some of these bounds are asymptotically sharp. We improve the known lower bound for the three-dimensional monomer–dimer entropy.
Linkedness and Ordered Cycles in Digraphs
Authors: KÜHN DANIELA , OSTHUS DERYK
Published: September 2007

Given a digraphD, let δ0(D) := min{δ+(D), δ−(D)} be the minimum semi-degree ofD. We show that every sufficiently large digraphDwith δ0(D)≥n/2 +l−1 isl-linked. The bound on the minimum semi-degree is best possible and confirms a conjecture of Manoussakis [17]. We also determine the smallest minimum semi-degree which ensures that a sufficiently large digraphDisk-ordered,i.e., that for every sequences1, . . .,skof distinct vertices ofDthere is a directed cycle which encounterss1, . . .,skin this order. This result will be used in [16].
Adipogenesis and lipotoxicity: role of peroxisome proliferator-activated receptor γ (PPARγ) and PPARγcoactivator-1 (PGC1)
Authors: Medina-Gomez Gema , Gray Sarah , Vidal-Puig Antonio
Published: September 2007

Obesity is characterised by an increase in the adipose deposits, resulting from an imbalance between food intake and energy expenditure. When expansion of the adipose tissue reaches its maximum limit, as in obesity, fat accumulates in non-adipose tissues such as liver, heart, muscle and pancreas, developing a toxic response known as lipotoxicity, a condition that promotes the development of insulin resistance and other metabolic complications. Thus, the lipotoxic state may contribute to the increased risk of insulin resistance, diabetes, fatty liver and cardiovascular complications associated with obesity.

We are interested in studying adipose tissue, specifically how mechanisms of adipogenesis and remodelling of adipose tissue, in terms of size and function of the adipocytes, could be considered a strategy to increase the capacity for lipid storage and prevent lipotoxicity. The peroxisome proliferator-activated receptors (PPARs) are a family of transcription factors that regulate energy balance by promoting either energy deposition or energy dissipation. Under normal physiological conditions, PPARγ is mainly expressed in adipose tissue and regulates diverse functions such as the development of fat cells and their capacity to store lipids. The generation of PPARγ knockout mice, either tissue specific or isoform specific, has provided new models to study PPARγ’s role in adipose tissue differentiation and function and have highlighted the essential role of PPARγ in adipogenesis and lipogenesis.

A second strategy to prevent lipotoxicity is to increase the capacity of tissues to oxidise fatty acids. PPARγcoactivator-1α is a coactivator of PPARγ that induces the expression of genes that promote the differentiation of preadipocytes to brown adipocytes. Recently, it has been implicated in increasing the oxidation of fatty acids via increasing mitochondrial capacity and function, making this co-factor a key candidate for the treatment of lipotoxicity.
Prevention of overweight and obesity: a Spanish approach
Authors: Aranceta Javier , Pérez-Rodrigo Carmen , Serra-Majem Lluis , Bellido Diego , de la Torre Martín López , Formiguera Xavier , Moreno Basilio
Published: September 2007

Background

Obesity is considered a major public health issue in most developed countries nowadays. This paper provides an overview of current population data available in Spain and the approach to develop preventive strategies in the country.

Methods

Review of population data available is based on individually measured weight and height as well as determinants. On this basis, the approach used in the country to develop preventive strategies is discussed.

Results

According to the DORICA study, the prevalence of obesity (BMI ≥30 kg m−2) is 15.5% in Spanish adults aged 25–60 years (13.2% in men and 17.5% in women). Obesity rates are higher among women aged 45 years and older, low social class, living in semi-urban places. Population estimates for the prevalence of obesity in Spanish children and young people based on the enKid study are 13.9% for the whole group. In this study, overweight and obesity is related to absence of breastfeeding, low consumption of fruit and vegetables, high consumption of cakes, buns, softdrinks and butchery products, low physical activity levels and a positive association with time spent watching TV.

In 2005, the Spanish Ministry of Health jointly with the Spanish Agency for Food Safety and Nutrition launched the multifaceted NAOS strategy for nutrition, physical activity and the prevention of obesity. The important role of the family and the school setting as well as the responsibility of the Health Administration and Pediatric Care in the prevention of obesity is highlighted in the document. The need for environmental actions is recognised. The PERSEO programme, a multicomponent school-based intervention project is part of the strategy currently in place.

Conclusion

Obesity is a public health issue in Spain. A national multifaceted strategy was launched to counteract the problem. Environmental and policy actions are a priority. Young children and their families are among the main target groups.
Physical activity, energy balance and obesity
Authors: Luís Griera José , María Manzanares José , Barbany Montserrat , Contreras José , Amigó Pilar , Salas-Salvadó Jordi
Published: September 2007

Obesity appears when energy intake exceeds energy expenditure. The most important variable compound of energy expenditure is physical activity. The global epidemics of obesity seem closely related to reduced physical activity and sedentariness widely increasing nowadays. Once obesity has developed, caloric intake becomes similar to energy expenditure. To lose weight, besides decreasing energy intake, energy expenditure must be increased. The promotion of physical activity is difficult and so the results of treatment of obesity are discouraging for doctors, other health professionals and patients. Proactive efforts from patients and health providers with an intensive feedback between them may be extremely helpful. Nevertheless, more studies are needed to provide better approaches on the role of physical activity for the prevention and treatment of obesity and for long-term weight-loss maintenance.
Determination of the Inelastic Mean-Free-Path and Mean Inner Potential for AlAs and GaAs Using Off-Axis Electron Holography and Convergent Beam Electron Diffraction
Authors: Chung Suk , Smith David J. , McCartney Martha R.
Published: September 2007

The mean-free-paths for inelastic scattering of high-energy electrons (200 keV) for AlAs and GaAs have been determined based on a comparison of thicknesses as measured by electron holography and convergent-beam electron diffraction. The measured values are 77 ± 4 nm and 67 ± 4 nm for AlAs and GaAs, respectively. Using these values, the mean inner potentials of AlAs and GaAs were then determined, from a total of 15 separate experimental measurements, to be 12.1 ± 0.7 V and 14.0 ± 0.6 V, respectively. These latter measurements show good agreement with recent theoretical calculations within experimental error.
Subdaily Growth Patterns and Organo-Mineral Nanostructure of the Growth Layers in the Calcitic Prisms of the Shell of Concholepas concholepas Bruguière, 1789 (Gastropoda, Muricidae)
Authors: Guzman Nury , Ball Alexander D. , Cuif Jean-Pierre , Dauphin Yannicke , Denis Alain , Ortlieb Luc
Published: September 2007

Fluorochrome marking of the gastropod Concholepas concholepas has shown that the prismatic units of the shell are built by superimposition of isochronic growth layers of about 2 μm. Fluorescent growth marks make it possible to establish the high periodicity of the cyclic biomineralization process at a standard growth rhythm of about 45 layers a day. Sulphated polysaccharides have been identified within the growth layers by using synchrotron radiation, whereas high resolution mapping enables the banding pattern of the mineral phase to be correlated with the layered distribution of polysaccharides. Atomic force microscopy has shown that the layers are made of nanograins densely packed in an organic component.
A Universal Equation for the Emission Range of X Rays from Bulk Specimens
Authors: Gauvin Raynald
Published: September 2007

The derivation of a universal equation to compute the range of emitted X rays is presented for homogeneous bulk materials. This equation is based on two fundamental assumptions: the φ(ρz) curve of X-ray generation is constant and the ratio of the emitted to the generated X-ray range is equal to the ratio of the emitted to the generated X-ray intensity. An excellent agreement is observed with data obtained from Monte Carlo simulations of 200,000 electron trajectories in C, Al, Cu, Ag, Au, and an Fe–B alloy with boron weight fractions equal to 0.01, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 0.99, performed with the electron beam energy varied from 1 to 30 keV in 1-keV steps. When the ratio of the generated X-ray range to the photon mean free path is much smaller than one, the emission X-ray range is equal to the generated X-ray range, but when this ratio is much greater than one, the emission X-ray range is constant and is given by the product of the effective photon mean free path multiplied by the sine of the take-off angle.
Salmonella–Host Cell Interactions, Changes in Host Cell Architecture, and Destruction of Prostate Tumor Cells with Genetically AlteredSalmonella
Authors: Zhong Zhisheng , Kazmierczak Robert A. , Dino Alison , Khreis Rula , Eisenstark Abraham , Schatten Heide
Published: September 2007

Increasingly, genetically modifiedSalmonellaare being explored as a novel treatment for cancer becauseSalmonellapreferentially replicate within tumors and destroy cancer cells without causing the septic shock that is typically associated with wild-typeS. typhimuriuminfections. However, the mechanisms by which genetically modifiedSalmonellastrains preferentially invade cancer cells have not yet been addressed in cellular detail. Here we present data that showS. typhimuriumstrains VNP20009, LT2, and CRC1674 invasion of PC-3M prostate cancer cells.S. typhimurium-infected PC-3M human prostate cancer cells were analyzed with immunofluorescence microscopy and transmission electron microscopy (TEM) at various times after inoculation. We analyzed microfilaments, microtubules, and DNA with fluorescence and immunofluorescence microscopy. 3T3 Phi-Yellow-mitochondria mouse 3T3 cells were used to study the effects ofSalmonellainfestation on mitochondria distribution in live cells. Our TEM results show gradual destruction of mitochondria within the PC-3M prostate cancer cells with complete loss of cristae at 8 h after inoculation. The fluorescence intensity in YFP-mitochondria-transfected mouse 3T3 cells decreased, which indicates loss of mitochondria structure. Interestingly, the nucleus does not appear affected bySalmonellawithin 8 h. Our data demonstrate that genetically modifiedS. typhimuriumdestroy PC-3M prostate cancer cells, perhaps by preferential destruction of mitochondria.
Conditional Random Surveying for Particle Deposition on a Mica Surface
Authors: Fu Jianzhong , Eschenazi Elia V. , Papadopoulos Kyriakos D.
Published: September 2007

In using microscopic imaging techniques, unbiased selection of sampling areas is often critical when judgment has to be used to find regions of interest. A conditional random sampling was designed to survey hematite particles on a mica surface using tapping-mode atomic force microscopy, based on three adapted-systematic-sampling methods designed to exclude subjective bias by limiting the freedom of arbitrarily selecting sampling areas. The results of these surveying methods were compared with the average particle surface density modeled by Poisson distribution. It was found that the conditional random sampling could survey particles effectively and improve the data reliability significantly. Ten population-known images from the same mica sheet were used to evaluate these methods, and an average relative error of 12% (maximum 21%) was obtained using the conditional random method with six sampling areas. It was used to investigate the effects of common organic pollutants, benzene, toluene, ethylbenzene, and xylenes on the transport of soil colloids.
Evolutionary catastrophes and the Goldilocks problem
Authors: Ćirković Milan M.
Published: September 2007

One of the mainstays of the controversial ‘rare Earth’ hypothesis is the ‘Goldilocks problem’ regarding various parameters describing a habitable planet, partially involving the role of mass extinctions and other catastrophic processes in biological evolution. Usually, this is construed as support for the uniqueness of the Earth's biosphere and intelligent human life. Here it is argued that this is a misconstrual and that, on the contrary, observation-selection effects when applied to catastrophic processes make it very difficult for us to discern whether the terrestrial biosphere and evolutionary processes which created it are exceptional in the Milky Way or not. This agnosticism, in turn, supports the validity and significance of practical astrobiological and SETI research.
Seamount morphology in the Bowie and Cobb hot spot trails, Gulf of Alaska
Authors: Chaytor Jason D. , Keller Randall A. , Duncan Robert A. , Dziak Robert P.
Published: September 2007

Full‐coverage multibeam bathymetric mapping of twelve seamounts in the Gulf of Alaska reveals that they are characterized by flat‐topped summits (rarely with summit craters) and by terraced, or step‐bench, flanks. These summit plateaus contain relict volcanic features (e.g., flow levees, late‐stage cones, and collapse craters) and as such must have been constructed by volcanic processes such as lava ponding above a central vent, rather than by erosion above sea level. The terraced flanks are composed of a sequence of stacked lava deltas and cones, probably tube‐fed from a central lava pond, a morphology which is suggestive of long‐lived, stable central lava sources and low to moderate eruption rates, indicative of significant time spent above a hot spot outlet. Most of these seamounts have summit plateaus surrounded, and cut into, by amphitheater headwall scarps, and flanks that are scarred by debris chutes, but lack visible debris accumulations at their base. We interpret the lack of blocky debris fields as evidence that the slope failures are mainly small‐scale debris flows, rather than large‐scale flank collapses. However, we cannot rule out the possibility that large flank‐collapse blocks from early in the histories of these seamounts are now hidden beneath the thick glacio‐fluvial fan deposits that cover the Gulf of Alaska seafloor. These slope failure features become smoother and longer and increase in size and abundance with increasing age of a seamount, suggesting that slope failure processes continue long after volcanic activity ceases.
Galvanic interpretation of self‐potential signals associated with microbial sulfate‐reduction
Authors: Williams Kenneth H. , Hubbard Susan S. , Banfield Jillian F.
Published: September 2007

We have evaluated the usefulness of the self‐potential (SP) geophysical method to track the onset and location of microbial sulfate‐reduction in saturated sediments during organic carbon amendment. Following stimulation of sulfate‐reducing bacteria (SRB) by addition of lactate, anomalous voltages exceeding 600 mV correlated in space and time with the accumulation of dissolved sulfide. Abiotic experiments in which the sulfide concentration at the measurement electrode was systematically varied showed a positive correlation between the magnitude of the SP anomaly and differences in the half‐cell potential associated with the measurement and reference electrodes. Thus, we infer that the SP anomalies resulted from electrochemical differences that developed between sulfide‐rich regions and areas having higher oxidation potential. In neither experiment did generation of an SP anomaly require the presence of an in situ electronic conductor, as is required by other models. These findings emphasize the importance of incorporation of electrochemical effects at electrode surfaces in interpretation of SP data from geophysical studies. We conclude that SP measurements provide a minimally invasive means for monitoring stimulated sulfate‐reduction within saturated sediments.
Oxygen sensing by ion channels
Authors: Kemp Paul J. , Peers Chris
Published: September 2007

The ability to sense and react to changes in environmental oxygen levels is crucial to the survival of all aerobic life forms. In mammals, specialized tissues have evolved which can sense and rapidly respond to an acute reduction in oxygen and central to this ability in many is dynamic modulation of ion channels by hypoxia. The most widely studied oxygen-sensitive ion channels are potassium channels but oxygen sensing by members of both the calcium and sodium channel families has also been demonstrated. This chapter will focus on mechanisms of physiological oxygen sensing by ion channels, with particular emphasis on potassium channel function, and will highlight some of the consensuses and controversies within the field. Where data are available, this chapter will also make use of information gleaned from heterologous expression of recombinant proteins in an attempt to consolidate what we know currently about the molecular mechanisms of acute oxygen sensing by ion channels.
Hypoxia in the central nervous system
Authors: LaManna Joseph C.
Published: September 2007

The brain, as a very high energy consumer, is completely reliant on molecular oxygen but because oxygen is dangerous due to toxicity [1], there are mechanisms which allow the brain to exist under low oxygen conditions when ‘idling’ but increase oxygen delivery when activated. This situation means that the brain can respond naturally to mild hypoxia with acute and chronic adaptive mechanisms. These mechanisms involve systemic and central metabolic and vascular processes that are mediated by hypoxia-inducible factor (HIF)-1. HIF-1-mediated cerebral angiogenesis is completed within 3 weeks of exposure onset and is reversible over the same time frame if normoxia is restored. Hypoxic acclimatizing responses may be significantly impaired with aging and metabolic or vascular disease.
Temporal Envelope Changes of Compression and Speech Rate: Combined Effects on Recognition for Older Adults
Authors: Jenstad Lorienne M. , Souza Pamela E.
Published: September 2007

Purpose

When understanding speech in complex listening situations, older adults with hearing loss face the double challenge of cochlear hearing loss and deficits of the aging auditory system. Wide-dynamic range compression (WDRC) is used in hearing aids as remediation for the loss of audibility associated with hearing loss. WDRC processing has the additional effect of altering the acoustics of the speech signal, particularly the temporal envelope. Older listeners are negatively affected by other types of temporal distortions, but this has not been found for the distortion of WDRC processing for simple signals. The purpose of this research was to determine the circumstances under which older adults might be negatively affected by WDRC processing and what compensatory mechanisms those listeners might be using for the listening conditions when speech recognition performance is not affected.

Method

Two groups of adults with mild to moderate hearing loss were tested: (a) young-old (62–74 years,n= 11) and (b) old-old (75–88 years,n= 14). The groups did not differ in hearing loss, cognition, working memory, or self-reported health status. Participants heard low-predictability sentences compressed at each of 4 compression settings. The effect of compression on the temporal envelope was quantified by the envelope difference index (EDI; T. W. Fortune, B. D. Woodruff, & D. A. Preves, 1994). The sentences were presented at three rates: (a) normal rate, (b) 50% time compressed, and (c) time restored.

Results

There was no difference in performance between age groups, or any interactions involving age. There was a significant interaction between speech rate and EDI value; as the EDI value increased, representing higher amounts of temporal envelope distortion, speech recognition was significantly reduced. At the highest EDI value, this reduction was greater for the time-compressed than the normal rate condition. When time was restored to the time-compressed signals, speech recognition did not improve.

Conclusion

Temporal envelope changes were detrimental to recognition of low-context speech for older listeners once a certain threshold of distortion was reached, particularly for rapid rate speech. For this sample tested, the effect was not age related within the age range tested here. The results of the time-restored condition suggested that listeners were using acoustic redundancy to compensate for the negative effects of WDRC distortion in the normal rate condition.
Recognition of Time-Compressed and Natural Speech With Selective Temporal Enhancements by Young and Elderly Listeners
Authors: Gordon-Salant Sandra , Fitzgibbons Peter J. , Friedman Sarah A.
Published: September 2007

Purpose

The goal of this experiment was to determine whether selective slowing of speech segments improves recognition performance by young and elderly listeners. The hypotheses were (a) the benefits of time expansion occur for rapid speech but not for natural-rate speech, (b) selective time expansion of consonants produces greater score increments than other forms of selective time expansion, and (c) older listeners benefit from time expansion of speech

Method

Participants (
n
= 10–16 per group) were younger and older adults with normal hearing or with hearing loss. A repeated-measures design was used to assess recognition of sentence-length stimuli presented in 2 baseline speech rates: natural and 50% time compression. Selective time expansion of consonants, vowels, or pauses was applied to the natural-rate and time-compressed sentence-length stimuli.

Results

Listeners showed excellent performance for natural-rate speech, regardless of time-expansion method. Recognition was significantly poorer for the time-compressed sentences, but performance by elderly listeners and listeners with hearing loss improved with selective time expansion, particularly when applied to consonant segments.

Conclusion

The findings support the hypothesis that older listeners and listeners with hearing impairment benefit from selective time expansion of consonants applied to rapid speech, without a corresponding decrement when applied to normal-rate speech.
Temporal Sequence of Swallow Events During the Oropharyngeal Swallow
Authors: Mendell Dorie A. , Logemann Jeri A.
Published: September 2007

Purpose

To (a) identify and characterize the temporal relation of selected structural movements during the oropharyngeal swallow across participants, (b) determine whether patterns of movement could be identified, and (c) determine whether the temporal relations were affected by aging and bolus characteristics.

Method

Retrospective analysis of videofluoroscopic swallows of 100 normal participants (age range = 22–92 years) was conducted. Two swallows each of 3-ml and 10-ml liquids and a 1–3-ml paste bolus were analyzed. The onset of a number of structural movements and bolus arrival points were compared against a single reference event: onset of upper esophageal sphincter (UES) opening.

Results

Normal participants demonstrated predominant sequences in pharyngeal movement patterns with some variability. The use of voluntary swallow maneuvers by these normal participants accounted for some degree of this variability. Volume, consistency, and age all affected the temporal relation between onset of specific motor events relative to the onset of UES opening. Increasing bolus volume was associated with a shorter temporal difference between UES opening and onset of other pharyngeal movements. In contrast, a thicker bolus was associated with longer temporal differences. Younger participants generally demonstrated shorter temporal differences between events than did older participants.

Conclusion

Temporal relations between structural movements are not fixed but can be systematically affected by bolus characteristics and age.
Automatic Measurement of Nonparticipatory Stiffness in the Perioral Complex
Authors: Seibel Lana M. , Barlow Steven M.
Published: September 2007

Purpose

To detail a novel automated technology developed in the authors' laboratory to quantitatively and noninvasively measure perioral passive stiffness in order to consider the feasibility of future applications in patients with facial movement disorders.

Method

A stiffness measurement system was developed, with corresponding data sampled from a group of 8 healthy women. Perioral electromyograms were sampled to confirm nonparticipation. A specially designed linear motor servo operating under position feedback was programmed to impose sequential step displacements of the lip at the oral angles over a span of approximately 24 mm. Real-time data acquisition and analysis of resultant force and displacement provide a quantitative, rapid, index of muscle rigidity (stiffness) during a do-not-contract condition.

Results

Nonlinear regression techniques revealed that the relation between perioral stiffness and imposed displacement was highly significant.

Conclusion

Given the probable relation between certain forms of neuromotor disease and facial rigidity, effects of bomb blast or missile injury on orofacial function, or stiffness changes due to tissue scarring after lip revision surgeries in children with clefts, it is likely that inclusion of facial stiffness measurements will be useful in the management of facial movement disorders.
TFIIS elongation factor and Mediator act in conjunction during transcription initiation
in vivo
Authors: Guglielmi Benjamin , Soutourina Julie , Esnault Cyril , Werner Michel
Published: September 2007

The transcription initiation and elongation steps of protein-coding genes usually rely on unrelated protein complexes. However, the TFIIS elongation factor is implicated in both processes. We found that, in the absence of the Med31 Mediator subunit, yeast cells required the TFIIS polymerase II (Pol II)-binding domain but not its RNA cleavage stimulatory activity that is associated with its elongation function. We also found that the TFIIS Pol II-interacting domain was needed for the full recruitment of Pol II to several promoters in the absence of Med31. This work demonstrated that, in addition to its thoroughly characterized role in transcription elongation, TFIIS is implicated through its Pol II-binding domain in the formation or stabilization of the transcription initiation complex
in vivo
.
Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling
Authors: Firestone R. B. , West A. , Kennett J. P. , Becker L. , Bunch T. E. , Revay Z. S. , Schultz P. H. , Belgya T. , Kennett D. J. , Erlandson J. M. , Dickenson O. J. , Goodyear A. C. , Harris R. S. , Howard G. A. , Kloosterman J. B. , Lechler P. , Mayewski P. A. , Montgomery J. , Poreda R. , Darrah T. , Hee S. S. Que , Smith A. R. , Stich A. , Topping W. , Wittke J. H. , Wolbach W. S.
Published: September 2007

A carbon-rich black layer, dating to ≈12.9 ka, has been previously identified at ≈50 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The
in situ
bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it. Causes for the extinctions, YD cooling, and termination of Clovis culture have long been controversial. In this paper, we provide evidence for an extraterrestrial (ET) impact event at ≅12.9 ka, which we hypothesize caused abrupt environmental changes that contributed to YD cooling, major ecological reorganization, broad-scale extinctions, and rapid human behavioral shifts at the end of the Clovis Period. Clovis-age sites in North American are overlain by a thin, discrete layer with varying peak abundances of (
i
) magnetic grains with iridium, (
ii
) magnetic microspherules, (
iii
) charcoal, (
iv
) soot, (
v
) carbon spherules, (
vi
) glass-like carbon containing nanodiamonds, and (
vii
) fullerenes with ET helium, all of which are evidence for an ET impact and associated biomass burning at ≈12.9 ka. This layer also extends throughout at least 15 Carolina Bays, which are unique, elliptical depressions, oriented to the northwest across the Atlantic Coastal Plain. We propose that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling. The shock wave, thermal pulse, and event-related environmental effects (e.g., extensive biomass burning and food limitations) contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.