cssi/SciSciGPT-SciSciNet huggingface dataset:
Elevated temperature compressive creep behavior of tungsten carbide-cobalt alloys

Abstract The compressive creep deformation of two-phase tungsten carbide-cobalt alloys with 12 and 15% Co has been investigated at temperatures of 800, 900, and 1000°C for stresses of 10,000 to 110,000 psi. At each temperature studied, the WC-Co alloys showed a decreasing steady-state creep rate with increasing WC particle size for low creep-stress levels. At high stress levels, the steady-state creep rate was observed to increase with increased WC particle size. These observations, with additional considerations of the creep behavior, indicated that two mechanisms were rate determining during deformation of WC-Co alloys. To ascertain the rate-determining mechanisms during deformation, existing creep models were extended to include the high volume loading of dispersed WC particles present in these alloys. At high stresses, the mechanism postulated to describe steady-state creep deformation was the looping of dislocations in the Co matrix between WC particles and the climb of pinched-off loops. The diffusion of Co in the matrix around WC particles has been suggested as the rate-controlling steady-state creep mechanism at low stresses.
Properties of the 78 meV acceptor in GaAs

Abstract An acceptor with a binding energy of 78 meV is frequently observed in LEC GaAs. As a commonly observed acceptor its identification and control are important aspects of materials development. It has recently been shown to be a double acceptor with a second level at 203 meV. Although it is a common center its origin has not yet been conclusively determined; both the gallium antisite and boron on the arsenic site are often proposed origins. Experimental and theoretical studies of this acceptor are reviewed including the identification of the center as a double acceptor, the origins of the various photoluminescence properties, infrared absorption by the electronic levels of this impurity, Raman studies of the S-states, and experiments bearing on its identification.
Specific bile acids inhibit hepatic fatty acid uptake in mice.

Bile acids are known to play important roles as detergents in the absorption of hydrophobic nutrients and as signaling molecules in the regulation of metabolism. Here we tested the novel hypothesis that naturally occurring bile acids interfere with protein-mediated hepatic long chain free fatty acid (LCFA) uptake. To this end stable cell lines expressing fatty acid transporters as well as primary hepatocytes from mouse and human livers were incubated with primary and secondary bile acids to determine their effects on LCFA uptake rates. We identified ursodeoxycholic acid (UDCA) and deoxycholic acid (DCA) as the two most potent inhibitors of the liver-specific fatty acid transport protein 5 (FATP5). Both UDCA and DCA were able to inhibit LCFA uptake by primary hepatocytes in a FATP5-dependent manner. Subsequently, mice were treated with these secondary bile acids in vivo to assess their ability to inhibit diet-induced hepatic triglyceride accumulation. Administration of DCA in vivo via injection or as part of a high-fat diet significantly inhibited hepatic fatty acid uptake and reduced liver triglycerides by more than 50%. In summary, the data demonstrate a novel role for specific bile acids, and the secondary bile acid DCA in particular, in the regulation of hepatic LCFA uptake. The results illuminate a previously unappreciated means by which specific bile acids, such as UDCA and DCA, can impact hepatic triglyceride metabolism and may lead to novel approaches to combat obesity-associated fatty liver disease.
MUTUAL ELECTROSTATIC INTERACTIONS BETWEEN CLOSELY SPACED CHARGED SOLDER DROPLETS

Emerging technologies of net-form manufacturing and electronic packaging rely on the use of precisely deposited molten metal droplets with sizes on the order of 100 μm in diameter. In many technological realizations, closely spaced droplets are electrostatically charged and deflected onto a substrate in a manner similar to ink-jet printing in order to “print” fine features onto a board for electronics applications or onto a substrate for net-form manufacturing. Unlike ink-jet printing, the aforementioned emerging technologies require the printing of large lateral dimensions onto the substrate by means of electrostatic charging and deflection (on the order of several centimeters), and hence these applications require the droplets to have significantly higher charges than in the ink-jet printing technology. The high charges of the closely spaced droplets can lead to inter-droplet electrostatic interactions that will cause significant deviations in the droplets’ trajectories. Hence, the understanding of the physics of inter-droplet electrostatic interactions is of primary importance in order to assure the fidelity of the net-formed component or the printed electronic package. In this work, we present a model that predicts the trajectories of the droplets when charged and deflected and corresponding experimental validations. Conditions for which electrostatic interactions are negligible are sought.
Struggles to beat the system

Science and Dissent in Post-Mao China: The Politics of Knowledge by H. Lyman Miller University of Washington Press: 1996. Pp. 370. $38 (hbk), $18.95 (pbk) Stalinist Science by Nikolai Krementsov Princeton University Press: 1997. Pp. 358. £37.50, $45.00
Evaluating effects of exposures on embryo viability and uterine receptivity in in vitro fertilization

We consider models for the occurrence of pregnancy following in vitro fertilization. In this clinical protocol, implantation depends on two factors: the receptivity of the uterus and the viability of at least one of the embryos transferred to the uterus. This work is motivated by the need to identify reliable bio-markers for these two factors, in order to enhance the success rate for couples undergoing this procedure. We present a general latent variable structure model for outcomes that take either one of two possible forms: as summed Bernoullis, based on an ultrasound count of gestational sacs, or as aggregated Bernoullis, based only on the outcome of a biochemical pregnancy test. We allow both uterine receptivity and embryo viability to be influenced by covariates. The proposed latent variable structure allows us to utilize the existing statistical packages to maximize an otherwise intractable likelihood function. The method is sufficiently flexible to permit any valid choice of link function. We illustrate by applying the method to a recent study of in vitro fertilization carried out in North Carolina. The number of cells at transfer is evidently a marker for embryo viability.
Analysis of order-statistic filters for robust detection

ABSTRACTIn detection systems (e.g. radar) , the effect of interference patterns (clutter) from the environ- ment are partially unknown and/or varying in terms of their statistical properties. In such instances, the performance of the optimal detector deteriorates significantly, and a nonparametricor constant false alarm rate (CFAR) detector which is designed to be insensitive to changes in theunderlying density functions of the clutter is needed. Order Statistic (OS) filters have been shownto perform effectively in detection systems when the observations are independent and identicallydistributed. When the assumptions about the observations are violated or the underlying distribu- tion of the clutter is altered, only certain ranks of the OS filter show robust performance. Thisstudy analyzes the performance of OS filters in the framework of nonparametric detection for cases in whh the observations do not contain equivalent statistical information or observationsare not independent. Through computer simulation, the extent of robustness that can be obtainedfrom different ranks is illustrated.II. INTRODUCTIONAn important step in binary detection (e.g., radar) is the extraction of target information froma set of observations in order to minimize some error criterion. A common error criterion used is
Orientation Effects on the High-Temperature Morphological Evolution of Pore Channels in Sapphire

Arrays of semi-infinite and of controlled-aspect-ratio pore channels, both of controlled orientation, were introduced into undoped basal-plane sapphire substrates, using microfabrication techniques, ion-beam etching, and hot pressing. The breakup of these channels via Rayleigh instabilities during a series of annealings at a temperature of 1700°C was monitored. In all cases, the channels broke up with a characteristic wavelength (λ) that was much larger than that expected for a material with isotropic surface energy, which reflected stabilization effects that were due to anisotropy of the surface energy. The break-up wavelength also was very dependent on orientation: channels that were oriented along the [11¯00] and [112¯0] directions yielded the smallest and largest pore spacings (λ-values), respectively, which is in qualitative agreement with prior observations. The critical (minimum) aspect ratio for the breakup of finite-length channels into multiple pores also is dependent upon channel orientation, and the trend mirrors that observed for semi-infinite channels. The pattern of channel evolution suggested two-fold rotational symmetry within the basal plane, where, because of the nature of the experiment, apparent six-fold symmetry is expected. Several factors that may contribute to or cause an apparent or real loss of symmetry have been discussed.
Gastrointestinal Reactions during a Noise Avoidance Task

Abstract : Recordings of gastrointestinal activity were obtained from 24 pairs of Ss during a rest period and while the experimental Ss performed a noise avoidance task. For the experimental Ss gastrointestinal motility as measured by amplitude showed significant increases during the task. The control Ss, unaware of the task and subjected to the same noises as their partners, showed no increases in gastrointestinal motility. (Author)
Intraoperative management of patients with incidental catecholamine producing tumors: A literature review and analysis.

Context: Present knowledge about intraoperative management, morbidity, and mortality of patients with undiagnosed catecholamine-producing tumors is mostly based on published case reports and anecdotal evidence. Aims: The aim was to summarize the management and outcomes of reported cases and analyze for practice patterns, deduct useful management recommendations as applicable. Settings and Design: The Medline database was searched with specific keywords for the period of 1988-2010 for cases of incidental pheochromocytomas and paragangliomas. Materials and Methods: Case reports in the English language with a postoperative diagnosis of pheochromocytoma and paraganglioma by histopathology were included. Systematic data extraction from case reports was done. Statistical analysis used: Descriptive statistics were applied. Results: Of 823 retrieved records, 62 case reports met inclusion criteria. Hemodynamic instability occurred primarily during mass manipulation/intraoperatively (52%, n = 32) and induction/laryngoscopy (18%, n = 11). In cases reporting specific antihypertensive treatments, nitrates (67%, n = 30) represented the majority of medications used, followed by beta-blockers (47%, n = 21). Alpha receptor blockers were administered in 33% (n = 15). The perioperative mortality was 8% (n = 5), and none of these patients received intraoperative alpha blockade. A catecholamine-secreting tumor was suspected intraoperatively in 26% of cases. Conclusions: The perioperative mortality based on the reviewed cases of incidental catecholamine producing tumors was less than would traditionally be expected. Intraoperative alpha receptor blockade to treat hypertension was reported in 33% of cases, and none of the patients with a fatal outcome had received it. A higher intraoperative index of suspicion and a lower threshold to consider alpha blocking medications for severe intraoperative hypertension may improve outcomes.
Influence of age on adenomatous polyposis coli and p53 mutation frequency in sporadic colorectal cancer—rarity of co-occurrence of mutations in APC, K-ras, and p53 genes

Previous studies have investigated the possibility that specific mutations may be related to specific clinicopathological features. However, most previous investigations included only an average age (40–80 years) group of sporadic colorectal cancers and, moreover, studied only a single gene in isolation. Therefore, the influence of age on these mutation frequencies remains unclear, despite age being considered a risk factor for genetic mutation. This study included 122 sporadic colorectal cancers from three different age groups and analyzed mutation frequencies of adenomatous polyposis coli (APC), K-ras, and p53 genes and microsatellite instability to determine their mutation frequencies and relationships with clinicopathological features. Significantly lower p53 mutation frequencies were observed among young (32 years old or younger) and old (86 years old or older) patient groups compared with an average age (39–85 years old) patient group (14.3% and 19.2% versus 51.5%, P<0.001). APC mutation frequency (11.8%) was significantly lower in highly aggressive (Dukes’ stage D) tumors (P=0.003) than in the other stage tumors (Dukes’ stage A, B, and C). Additionally, simultaneous occurrence of all three genetic alterations in an individual tumor was rare (below 5%). Statistical analysis further confirmed that mutation number in Dukes’ D tumors occurred less frequently than expected in other stage tumors (P=0.008). Genetic alterations of sporadic colorectal cancers have different relationships with age or tumor stage. Additionally, most sporadic colorectal tumors do not necessarily require following the widely accepted genetic model, because the three key genetic mutations, APC, K-ras, and p53, rarely occur simultaneously.
A simple test for myocardial infarction

Abstract Background: The purpose of this study was to determine the feasibility of using a first pass phase map of the ventricular blood pool to detect and localize acute myocardial infarction (AMI). Methods: Subjects: 50 sequential patients had first time acute MI localized by well defined focal pyrophosphate (pyp) uptake with Ecg, enzyme and clinical confirmation. During this same period of time 16 patients were admitted to rule out MI and showed no pyp uptake, or other findings of AMI. Technique: 20 mCi of 99mTc pyp was bolus injected into all subjects admitted to RO MI. Using a small mobile camera 30 deg RAO planar first pass data was acquired in list mode with millisecond time markers. Representative cycles were constructed from the two highest count RV and the three highest LV beats. Each of these chosen heart beats were individually divided into time segments that were 1/16 of the beat length to 1 ms precision. The corresponding segments were then added. The valve planes (which are nearly perpendicular to the RAO imaging plane) are defined by functional techniques. A first harmonic phase map was then reapplied to the ventricular blood strictly limited by the valve planes and diastolic pool edges. The location of a phase defect was shown on the RAO (long axis) color coded ventricular map and the size of the defect was quantitated in a corresponding histogram of all of the pixels in the map. The computer generated map was available immediately after the 20 second angiogram and was interpreted without knowledge of subsequent findings. Regional wall motion (RWM) by sequential isocount contours during the cardiac cycle. RVEF and LVEF as well as LVEDV and pulmonary transit time were also calculated After 4 to 6 hours repeat angiography was performed with 99mTc DTPA in the optimum view to superimpose the static pyp image. Results: 48 of the 50 MIs were correctly localized in the RAO ventricular phase maps. Two posterolateral wall infarcts were not detected. 38 of the infarcts had corresponding RWM defects. In general the phase maps were much easier to interpret and quantitate than the RWM displays. None of the 16 non MI subjects had phase defects. Conclusion: The rapidity and simplicity of this test suggests a roll in screening for AMI especially in subjects without prior history of AMI.
Catch the KIF5B Train to the Apical Surface

As epithelial cells become polarized, they develop new pathways to send proteins to the apical or basolateral domains of their plasma membrane. In this issue of Developmental Cell, Jaulin et al. (2007) show that as polarity develops, there is a shift in the kinesin motor protein used to transport an apical protein to the cell surface.
Damping of structural vibrations with piezoelectric materials and passive electrical networks

The possibility of dissipating mechanical energy with piezoelectric material shunted with passive electrical circuits is investigated. The effective mechanical impedance for the piezoelectric element shunted by an arbitrary circuit is derived. The shunted piezoelectric is shown to possess frequency dependent stiffness and loss factor which are also dependent on the shunting circuit. The generally shunted model is specialized for two shunting circuits: the case of a resistor alone and that of a resistor and inductor. For resistive shunting, the material properties exhibit frequency dependence similar to viscoelastic materials, but are much stiffer and more independent of temperature. Shunting with a resistor and inductor introduces an electrical resonance, which can be optimally tuned to structural resonances in a manner analogous to a mechanical vibration arsorber. Techniques for analyzing systems which incorporate these shunting cases are presented and applied to a cantilevered beam experiment. The experimental results for both the resistive and resonant shunting circuits validate the shunted piezoelectric damping models.
After-school care for children: A resilience-based approach

This paper utilizes a resilience perspective and a review of research to identify societal, community, family, and individual factors related to the after-school period that place many children at increased risk for poor developmental and behavioral outcomes. We define and discuss the importance of four key dimensions of children's after-school experiences: safety, developmental appropriateness, cultural relevance, and stability. We recommend that families and practitioners collaborate and include children in the decision making to create after-school care that is individualized. Whenever possible, after-school settings should include opportunities for both enhancing academic achievement and having fun. While emphasizing that all children need appropriate after-school environments, we discuss the importance of assessment and of plan development and monitoring when working with youths at risk for aggressive behavior, impaired relationships with peers and adults, and poor performance in school.
Multinodular Goiter and Primary Hyperparathyroidism: A Circuitous Route to Diagnosing Metastatic Uveal Melanoma

Uveal melanoma spreads exclusively via a hematogenous route and is notable for its latency. Liver metastases are common; however, metastatic spread to unusual sites has been encountered. We report the case of metastatic uveal melanoma in a woman with multinodular goiter and primary hyperparathyroidism. The patient presented with hypercalcemia and an elevated intact parathyroid hormone level, in conjunction with a follicular neoplasm in the setting of goiter. She underwent an uneventful total thyroidectomy and parathyroidectomy. Postoperatively, she became normocalcemic. Histopathologic analyses revealed metastatic uveal melanoma cells within both the multinodular goiter and parathyroid adenoma. At present, she is enrolled in a phase II trial for disseminated uveal melanoma. This is a report of uveal melanoma metastatic to both a parathyroid adenoma and a nodular hyperplastic thyroid. Additionally, this case serves to display the unusual metastatic potential of uveal melanoma.
Plasticity at really diminished length scales

In recent years, the plastic behavior of technologically attractive nanocrystalline materials has become more prominent in the mainstream scientific community. In this work a short review on the current understanding of the effects of microstructural characteristics on mechanical behavior of nanocrystalline materials produced by different methods including severe plastic deformation is presented. The microstuctural information with the mechanical data obtained from these nanoscale materials was analyzed in the context of plasticity at truly diminished length scales. Experimental data arising from testing at different conditions clearly demonstrate that some microstructural features other than just grain size (grain boundary structure, grain size distribution, etc.) can also be responsible for the exhibited material behavior. Special emphasis is given to the difficulty of intragranular dislocation generation in nanoscale structures at diminished dimensional scales and its effect on accommodation processes in grain boundary mediated plastic behavior.
Risk minimization practices for pregnancy prevention: understanding risk, selecting tools

According to the March of Dimes, approximately 4% (1/28) of babies are born in the US each year with a birth defect. For the majority of birth defects the etiology is unknown, although chemicals, including drug exposures, probably account for less than 1% of all birth defects. The identification of potential human teratogenicity during drug development is important because drug-induced adverse fetal effects are potentially preventable with the application of risk assessment strategies and risk minimization tools and programs to minimize risk of pregnancy exposure while preserving access to drug benefits; risk assessment and risk minimization together comprise risk management. It is important that risk minimization programs intended to limit fetal exposure use a consistent approach and are tailored to the product-specific risk concerns in order to optimize the benefit-risk balance for a particular drug. This paper highlights general considerations in developing specific risk minimization programs to prevent fetal drug exposure including the relative advantages and disadvantages of each strategy.
Acute toxicity of vanadium to two species of freshwater fish.

Goldfish (Carassius auratus) and guppies (Lebistes reticulatus) were the two freshwater, thermophilous fishes chosen for use in this study. These species were selected for the following reasons: (1) low cost/individual, (2) ready availability, (3) ease of care and handling, (4) suspected differences between the two species in their responses to this metal, and (5) the usefulness of both as generalized models for the response of freshwater and marine fishes to vanadium.
Acan125 binding to the SH3 domain of acanthamoeba myosin-IC.

Abstract The domain organization of Acanthamoeba myosin-I, an oligomodular motor protein, includes a potentially important protein interaction module that is mostly uncharacterized. The Src homology 3, SH3, domain of myosin-I binds Acan125, a protein containing at least two consensus ligand binding domains: C-terminal SH3 binding motifs (PXXP) and N-terminal leucine-rich repeats. We report the first affinities determined for an SH3 domain of any myosin, namely, K d = 7 μM for a 21-residue synthetic peptide based on the PXXP domain sequence and K d = 0.15 μM for the PXXP domain included in the C-terminus of Acan125. These values are consistent with affinities reported for peptides and proteins that associate with SH3. By deletional analysis we show that only the PXXP domain is required for Acan125 to interact with the SH3 domain of Acanthamoeba myosin-IC (AmyoC(SH3)). The synthetic peptide described above at a concentration near the K d for SH3 binding blocked the interaction between native AmyoC and Acan125, mapping the interaction to the PXXP domain of Acan125 and the SH3 domain of myosin-I. These results are consistent with prototypical SH3 binding and suggest that a PXXP module is both necessary and sufficient to interact with an SH3 module of myosin-I.
Transport of organic carbon to the oceans by rivers of North America: a synthesis of existing data ''

Transport of organic carbon in rivers of North America to the oceans was assessed by compiling and analyzing data from 82 North American rivers draining 60% of Canada and the United States. These data were collected by the U.S. Geological Survey and the Water Resources Branch of Canada's Inland Waters Directorate. Mean annual concentrations of total organic carbon showed considerably less variation than did annual specific export (gC m -2 yr -1 ). Regional variation in annual specific export of total organic carbon was attributed primarily to differences in annual runoff. Transport of total organic carbon to coastal regions by North American rivers totalled about 35 × 10 12 ± 5 × 10 12 gC yr -1 in 1977 and 1978. The total organic carbon flux to the oceans associated with the long-term average annual flow in North American rivers was computed to be about 40 × 10 12 gC yr -1 , slightly larger than that in 1977 and 1978 because of the lower-than-average runoff in some regions those years. DOI: 10.1111/j.2153-3490.1982.tb01805.x
Executive Function The Search for an Integrated Account

In general, executive function can be thought of as the set of abilities required to effortfully guide behavior toward a goal, especially in nonroutine situations. Psychologists are interested in expanding the understanding of executive function because it is thought to be a key process in intelligent behavior, it is compromised in a variety of psychiatric and neurological disorders, it varies across the life span, and it affects performance in complicated environments, such as the cockpits of advanced aircraft. This article provides a brief introduction to the concept of executive function and discusses how it is assessed and the conditions under which it is compromised. A short overview of the diverse theoretical viewpoints regarding its psychological and biological underpinnings is also provided. The article concludes with a consideration of how a multilevel approach may provide a more integrated account of executive function than has been previously available.
Arachne: a portable threads system supporting migrant threads on heterogeneous network farms

We present the design and implementation of Arachne, a threads system that can be interfaced with a communications library for multithreaded distributed computations. In particular, Arachne supports thread migration between heterogeneous platforms, dynamic stack size management, and recursive thread functions. Arachne is efficient, flexible, and portable-it is based entirely on C and C++. To facilitate heterogeneous thread operations, we have added three keywords to the C++ language. The Arachne preprocessor takes as input code written in that language and outputs C++ code suitable for compilation with a conventional C++ compiler. The Arachne runtime system manages all threads during program execution. We present some performance measurements on the costs of basic thread operations and thread migration in Arachne and compare these to costs in other threads systems.
Minding Motherhood and the Burden of an Ancient Blessing: “May You Be the Mother of a Hundred Sons”

This performance is crafted within the narrow space of the author’s existence as a human, as a person, as a female, and as a mother. The rich, intricate experience of a life lived out as a mother o...
The ribosome – a macromolecular machine par excellence

The ribosome is the site in the cell where proteins are synthesized. Cryo-electron microscopy and X-ray crystallography have revealed the ribosome as a particle made of two subunits, each formed as an intricate mesh of RNAs and many proteins. Ligand-binding experiments followed by cryo-electron microscopy have helped to determine some of the key stages of interaction between the ribosome and the main ligand molecules.
Grazing bifurcations in periodic hybrid systems

Grazing bifurcations occur when a small parameter variation induces a change in the event sequence of a hybrid system, i.e., a system where continuous dynamics and discrete events strongly interact. At such a bifurcation, the system trajectory makes tangential contact with (grazes) an event triggering hypersurface. This bounding case separates regions of (generally) quite different dynamic behaviour. The paper formulates the conditions governing grazing bifurcation points, and extends those conditions to limit cycles. A shooting method is used to solve for bifurcating limit cycles. The approach is applicable for general nonlinear hybrid systems.
Systemic Inflammatory Markers, Periodontal Diseases, and Periodontal Infections in an Elderly Population

OBJECTIVES: To study the levels of systemic markers for inflammation with parameters of periodontal diseases in older people. DESIGN: A cross-sectional study was conducted in a cohort that is being followed prospectively on the effects of aging and body composition on morbidity. SETTING: University of Pittsburgh, Pittsburgh, and University of Tennessee, Memphis. PARTICIPANTS: One thousand one hundred thirty-one participants (mean age+/-standard deviation 72.7+/-2.8); 66% white and 50% male. MEASUREMENTS: Periodontal examination, including probing depth and attachment loss, was performed. Periodontal disease extent was divided into 0% of sites with probing depth of 6 mm or more, 1% to 10% of sites with probing depth of 6 mm or more and more than 10% of sites with probing depth of 6 mm or more. Subgingival plaque samples were collected from four molar teeth, and the levels of periodontal pathogens were determined using the benzoyl-DL-arginine-naphthylamide (BANA) test. Plasma interleukin-6 (IL-6), C-reactive protein (CRP), plasminogen activator inhibitor type-1 (PAI-1), and tumor necrosis factor alpha (TNF-alpha) levels were measured in all participants. Assessments of risk factors associated with elevated levels of markers of systemic inflammation were also determined. Multiple regression analysis was employed to analyze the data. RESULTS: IL-6 levels were significantly higher in participants with more-extensive periodontal disease than in other participants. Periodontal disease extent was significantly associated with higher TNF-alpha plasma levels, controlling for established risk factors for elevated TNF-alpha levels. Participants with BANA-positive species had significantly higher CRP plasma levels when controlling for risk factors for elevated CRP levels. CONCLUSION: Periodontal disease and infection may be modifiable risk indicators for elevated levels of systemic inflammatory markers in older people
Letting girls speak out about science

I conducted this study because I was interested in the question of why attitude research indicated that girls did not like science and were less likely to pursue a career in science. I was also puzzled about the drop in interest in science that occurred around the time students made the transition from elementary to high school.
Spermatogonial stem cell regulation and spermatogenesis

This article will provide an updated review of spermatogonial stem cells and their role in maintaining the spermatogenic lineage. Experimental tools used to study spermatogonial stem cells (SSCs) will be described, along with research using these tools to enhance our understanding of stem cell biology and spermatogenesis. Increased knowledge about the biology of SSCs improves our capacity to manipulate these cells for practical application. The chapter concludes with a discussion of future directions for fundamental investigation and practical applications of SSCs.
Regeneration patterns in old-growth red fir-western white pine forests in the northern Sierra Nevada, Lake Tahoe, USA

Abstract Red fir ( Abies magnifica ) forests in the Sierra Nevada are known to demonstrate both shade tolerant and disturbance related regeneration making it difficult to understand the role of disturbances in the regeneration dynamics of the forests. Four stands with different structural characteristics were selected for intensive sampling in order to capture the observed range of structural variability (e.g. composition, age, size and spatial pattern) in an old-growth red fir–western white pine ( Pinus monticola ) forest in the northern Sierra Nevada. We used detailed stem mapping, stand structural analysis and cross-dated fire scar samples to identify the relationships between disturbances and stand structure. All trees >5 cm dbh within four 0.5-ha plots were aged and mapped. The species composition of the plots was similar but the density and basal area of the tree populations varied among the plots. Red fir density and basal areas are greater than that of western white pine. The age structure indicated continuous, but variable recruitment and there were few seedlings and saplings. The mean point fire return interval was 76 years (range 25–175 years) for the 400-ha study area. Most fires scarred only single samples suggesting that burns were small and patchy, but pulses of recruitment suggest that some fires were moderate in severity. Regeneration pulses coincided with the dates of several fires (e.g. 1636, 1770). Moran's I , a measure of spatial autocorrelation, indicated that red fir and western white pine exhibited positive spatial autocorrelation at short (3–12 m) and intermediate (36–75 m) distances. Groups of similar age trees were spatially discrete and groups of different ages tended to overlap, resulting in an all aged forest. The spatial pattern of tree ages and the record of disturbance indicate that infrequent moderate severity fires have a lasting influence on the structure and development of old-growth red fir forests.
Alternative Management of Roadside Vegetation

ADDITIONAL INDEX WORDS. acetic acid, citric, clove oil, corn gluten meal, pelargonic, glufosinate-ammonium, glyphosate, mulch SUMMARY. Management of vegetation is an important element of roadside maintenance for safety and aesthetics. Current methods of management by highway departments principally involve mowing and the use of conventional, chemical herbicides. This research addressed use of herbicides (citric acid, clove oil, corn gluten meal, and pelargonic acid) that are considered as alternatives to conventional herbicides and the use of mechanical treatments of woodchip and bark mulches and burning. These alternative methods were compared with the use of conventional herbicides to assess the relative efficacy of treatments on roadside sites. A single application of pelargonic acid demonstrated immediate or short-term suppression of growth of vegetation; however, the efficacy lasted for no more than 6 weeks, after which regrowth was not distinguishable from untreated vegetation. Repeated applications of pelargonic acid will be necessary for season-long efficacy. Formulations of citric-acetic acid gave no control or only weak suppression of vegetative growth soon after application, and no suppression was evident after 6 weeks, suggesting that these materials have only limited use in roadside environments. The effects of burning lasted for about 6 weeks. No suppression of growth of roadside vegetation occurred with the use of corn gluten meal, which acted as a nitrogen fertilizer to promote growth. Mulches of bark or woodchips were strongly suppressive against emerging vegetation for 2 years, but were more effective in the first year than in the second year after application. The costs of materials and labor for the alternative practices were substantially more than for the conventional herbicides used in this study.
Analysis of 250 Consecutively Evaluated Cases of Workers' Disability Claims for Dermatitis

• Two hundred fifty individuals who filed claims for workers' disability compensation benefits for work-related dermatoses were evaluated in the private-practice setting of the author. Preset standard guidelines were used to assess the validity of work relevancy for each claimant. The findings in this retrospective study that included workers from 14 different industrial milieus revealed that 127 of 250 examinees had skin findings that were consistent with the respective workplace exposure. ( Arch Dermatol. 1990;126:782-786)
Dispersal of Fine Sediment in Nearshore Coastal Waters

Warrick, J.A., 2013. Dispersal of fine sediment in nearshore coastal waters. Journal of Coastal Research, 29(3), 579‐596. Coconut Creek (Florida), ISSN 0749-0208. Fine sediment (silt and clay) plays an important role in the physical, ecological, and environmental conditions of coastal systems, yet little is known about the dispersal and fate of fine sediment across coastal margin settings outside of river mouths. Here I provide simple physical scaling and detailed monitoring of a beach nourishment project near Imperial Beach, California, with a high portion of fines (~40% silt and clay by weight). These results provide insights into the pathways and residence times of fine sediment transport across a wave-dominated coastal margin. Monitoring of the project used physical, optical, acoustic, and remote sensing techniques to track the fine portion of the nourishment sediment. The initial transport of fine sediment from the beach was influenced strongly by longshore currents of the surf zone that were established in response to the approach angles of the waves. The mean residence time of fine sediment in the surf zone—once it was suspended—was approximately 1 hour, and rapid decreases in surf zone fine sediment concentrations along the beach resulted from mixing and offshore transport in turbid rip heads. For example, during a day with oblique wave directions and surf zone longshore currents of approximately 25 cm/s, the offshore losses of fine sediment in rips resulted in a 95% reduction in alongshore surf zone fine sediment flux within 1 km of the nourishment site. However, because of the direct placement of nourishment sediment on the beach, fine suspended-sediment concentrations in the swash zone remained elevated for several days after nourishment, while fine sediment was winnowed from the beach. Once offshore of the surf zone, fine sediment settled downward in the water column and was observed to transport along and across the inner shelf. Vertically sheared currents influenced the directions and rates of fine sediment transport on the shelf. Sedimentation of fine sediment was greatest on the seafloor directly offshore of the nourishment site. However, a mass balance of sediment suggests that the majority of the fine sediment moved far away (over 2 km) from the nourishment site or to water depths greater than 10 m, where fine sediment represents a substantial portion of the bed material. Thus, the fate of fine sediment in nearshore waters was influenced strongly by wave conditions, surf zone and rip current transport, and the vertical density and flow conditions of coastal waters.
Self-patterned gold electroplated multicapillary separation columns

This paper reports on a method for self-patterned electroplating to selectively deposit gold on vertical surfaces of microfabricated silicon structures. This method was developed out of the effort to realize microfabricated multicapillary columns (µMCC) for chromatographic separation aimed for handheld chemical analysis. Results showed the successful selective vertical wall electroplating of µMCCs comprising an unprecedented number of channels (8 and 16). The µMCCs were functionalized using self-assembly of thiol groups and evaluated for their chromatographic performance. µMCCs demonstrated high separation efficiency as indicated by the 6500/m theoretical plate number and proved to have high sample capacities, which increases with the number of capillaries operating in parallel in these MEMS columns.
Modulation Scheme for Three-Phase Differential-Mode Ćuk Inverter

Three-phase differential-mode inverters are single-stage inverters, which have the potential to reduce the number of devices and cost with higher power density. Among such inverter topologies, differential-mode three-phase Cuk inverter (DTCI) has some advantage over other topologies, including modularity, lower number of switches, bidirectional power flow capability, and galvanic isolation. DTCI is a promising configuration for renewable-/alternative-energy applications with isolated and nonisolated structures. The continuous modulation scheme (CMS), which was introduced originally for the DTCI, activates all of three modules of the inverter. CMS increases the circulating power in modules and hence increases inverter power loss. This paper describes a discontinuous modulation scheme (DMS) for the DTCI which deactivates one module at a time resulting in a discontinuous operation of the inverter modules. The experimental open- and closed-loop results of DMS- and CMS-based DTCI are provided and compared. DMS reduces the circulating power, device voltage ratings, and mitigates the DTCI losses. The DTCI exhibits a nonlinear voltage gain with both DMS and CMS. It has been demonstrated that by feed-forwarding the input voltage and incorporating a static linearization method, the harmonic distortion of the output voltage is considerably reduced.
2D Differential In-gel Electrophoresis for the Identification of Esophageal Scans Cell Cancer-specific Protein Markers

The reproducibility of conventional two-dimensional (2D) gel electrophoresis can be improved using differential in-gel electrophoresis (DIGE), a new emerging technology for proteomic analysis. In DIGE, two pools of proteins are labeled with 1-(5-carboxypentyl)-1′-propylindocarbocyanine halide (Cy3) N-hydroxy-succinimidyl ester and 1-(5-carboxypentyl)-1′-methylindodi-carbocyanine halide (Cy5) N-hydroxysuccinimidyl ester fluorescent dyes, respectively. The labeled proteins are mixed and separated in the same 2D gel. 2D DIGE was applied to quantify the differences in protein expression between laser capture microdissection-procured esophageal carcinoma cells and normal epithelial cells and to define cancer-specific and normal-specific protein markers. Analysis of the 2D images from protein lysates of ∼ 250,000 cancer cells and normal cells identified 1038 protein spots in cancer cell lysates and 1088 protein spots in normal cell lysates. Of the detected proteins, 58 spots were up-regulated by >3-fold and 107 were down-regulated by >3-fold in cancer cells. In addition to previously identified down-regulated protein annexin I, tumor rejection antigen (gp96) was found up-regulated in esophageal squamous cell cancer. Global quantification of protein expression between laser capture-microdissected patient-matched cancer cells and normal cells using 2D DIGE in combination with mass spectrometry is a powerful tool for the molecular characterization of cancer progression and identification of cancer-specific protein markers.
The impact of increased body mass index on the clinical course of Crohn's disease.

Background & Aims: Tumor necrosis factor-α production in adipose tissue is well documented. Crohn's disease (CD) patients with increased adipose tissue may have more severe disease. This study evaluated overweight patients with CD to determine if their clinical course differs from those with a normal or low body mass index (BMI). Methods: Patients at the Hospital of the University of Pennsylvania from 1997 to 2002 were included. Data were collected from outpatient records and standardized interviews. Overweight was defined as a BMI of 25 kg/m 2 or higher. The primary outcome was time to first surgery. Secondary outcomes included age at diagnosis, number of surgeries, and escalation of therapy. Patients with a BMI of 25 kg/m 2 or higher at diagnosis were compared with patients with a BMI of less than 25 kg/m 2 using statistical analyses. Survival analysis compared time to first surgery. Results: A total of 148 patients were included. Forty-eight (32.4%) had a BMI of 25 kg/m 2 or higher at diagnosis. Patients with a BMI of 25 kg/m 2 or higher were older at diagnosis; 35 years vs 22.5 years for patients with a BMI of less than 25 kg/m 2 ( P = .0001). The number of surgeries, escalation of therapy, and disease distribution did not differ between the 2 groups. A significant difference was found for time to first surgery, 252 months vs 24 months for patients with a BMI of less than 18.5 kg/m 2 vs patients with a BMI of 25 kg/m 2 or higher, respectively ( P = .043). Conclusions: CD patients with a BMI of 25 kg/m 2 or higher at diagnosis were older at diagnosis and had a shorter time to first surgery than those with a BMI of less than 18.5 kg/m 2 . This suggests that overweight CD patients require earlier surgical intervention and perhaps more aggressive medical therapy.
Interactions of Calmodulin and α-Actinin with the NR1 Subunit Modulate Ca2+-Dependent Inactivation of NMDA Receptors

Glutamate receptors are associated with various regulatory and cytoskeletal proteins. However, an understanding of the functional significance of these interactions is still rudimentary. Studies in hippocampal neurons suggest that such interactions may be involved in calcium-induced reduction in the open probability of NMDA receptors (inactivation). Thus we examined the role of the intracellular domains of the NR1 subunit and two of its binding partners, calmodulin and α-actinin, on this process using NR1/NR2A heteromers expressed in human embryonic kidney (HEK) 293 cells. The presence of the first 30 residues of the intracellular C terminus of NR1 (C0 domain) was required for inactivation. Mutations in the last five residues of C0 reduced inactivation and produced parallel shifts in binding of α-actinin and Ca2+/calmodulin to the respective C0-derived peptides. Although calmodulin reduced channel activity in excised patches, calmodulin inhibitors did not block inactivation in whole-cell recording, suggesting that inactivation in the intact cell is more complex than binding of calmodulin to C0. Overexpression of putative Ca2+-insensitive, but not Ca2+-sensitive, forms of α-actinin reduced inactivation, an effect that was overcome by inclusion of calmodulin in the whole-cell pipette. The C0 domain also directly affects channel gating because NR1 subunits with truncated C0 domains that lacked calmodulin or α-actinin binding sites had a low open probability. We propose that inactivation can occur after C0 dissociates from α-actinin by two distinct but converging calcium-dependent processes: competitive displacement of α-actinin by calmodulin and reduction in the affinity of α-actinin for C0 after binding of calcium to α-actinin.
The hmp chemotaxis cluster regulates gliding in the filamentous cyanobacterium Nostoc punctiforme.

Summary Many bacteria are capable of movement over surfaces without flagella or pili; they glide. Nostoc punctiforme is a cyanobacterium that differentiates specialized gliding filaments called hormogonia, but the mechanism underlying their movement is currently unknown. Risser et al. characterize the hormogonia motility and polysaccharide (hmp) locus that encodes proteins homologous to well-studied chemotaxis systems. All but one of the genes in the locus were required for gliding motility and each protein localized as a ring near the cell junction. One protein, the CheA homologue HmpE, was capable of autophosphorylation and phosphotransfer to the CheY homologue HmpB. This study reveals the hmp locus as an important regulator of gliding and highlights N. punctiforme as a model for understanding gliding motility in a complex multicellular bacterium.
Thermal polymerization of butadiene to solid polymer

That rate of formation of solid polymer has been determined for pure butadiene as well as for the two-phase system of butadiene plus water, with and without the addition of added peroxides. Benzene-insoluble polymer was formed only in the absence of added peroxides.