cssi/SciSciGPT-SciSciNet huggingface dataset:
Protein folding and de novo protein design for biotechnological applications

In the postgenomic era, the medical/biological fields are advancing faster than ever. However, before the power of full-genome sequencing can be fully realized, the connection between amino acid sequence and protein structure, known as the protein folding problem, needs to be elucidated. The protein folding problem remains elusive, with significant difficulties still arising when modeling amino acid sequences lacking an identifiable template. Understanding protein folding will allow for unforeseen advances in protein design; often referred to as the inverse protein folding problem. Despite challenges in protein folding, de novo protein design has recently demonstrated significant success via computational techniques. We review advances and challenges in protein structure prediction and de novo protein design, and highlight their interplay in successful biotechnological applications.
On the Connectivity Analysis over Large-Scale Hybrid Wireless Networks

Many real systems are hybrid networks which include infrastructure nodes in multi-hop wireless networks, such as sinks in sensor networks and mesh routers in mesh networks. However, we have very little understanding of network connectivity in such networks. Therefore, in this paper, we consider hybrid networks denoted by $H(\alpha,\beta)$ with ad hoc nodes and base stations and prove how base stations can improve the connectivity of ad hoc nodes in {\em subcritical phase}, that is, the ad hoc node density, $\lambda_{\alpha}$ is lower than the critical density $\lambda_{\alpha}^c$. We find that with the existence of a positive density of base stations, i.e., the density of base stations $\lambda_{\beta}>0$ which have the same transmission range as ad hoc nodes, the number of connected ad hoc nodes is $\Theta(n)$ with probability nearly $1$, where $n$ is the number of ad hoc nodes. However, the size of connected ad hoc component scales linearly with $\lambda_{\beta}$ when it is lower than $c_1(\lambda_{\alpha})$ with probability nearly $1$, which demonstrates a tremendous benefit of using base stations to enhance the connectivity of ad hoc nodes. Further, we study a hybrid network architecture that makes a significant connectivity improvement with transmission range $r_{\beta}$ larger than $r_{\alpha}$ for ad hoc nodes. Therefore, our results provide a theoretical understanding of to what extent ad hoc nodes can benefit from base stations in multi-hop wireless networks.
China's hi-tech thrust: Beijing's evolving approaches to the process of innovation

Abstract In an effort to narrow the technological gap between itself and the industrialized world, China is actively engaged in promoting the development of hightechnology industries. In March 1986, for example, China's State Science and Technology Commission launched the “863” program, which provides extra-budgetary funding for supporting high-tech innovation. What is conspicuous about recent Chinese efforts, however, is the willingness to allow many nontraditional centers of innovative activity to emerge, such as the Haidian district near Beijing University. The emergence of these alternative loci of technological dynamism suggest that the primary sources of innovation may be gradually, albeit steadily, shifting away from preexisting institutions and research units.
SEX STEREOTYPING OF THE ELDERLY BY CHILDREN

The purpose of this study was to investigate whether elementary pupils stereotype older people and, more specifically, whether they stereotype them by sex. Photographs of a young woman and man and an old woman and man were shown to the subjects. Subjects were then asked to select the adjective from each of five pairs of adjectives which best described the person, such as happy or sad. Then subjects were asked six questions designed to assess their willingness to associate socially with the persons depicted in the photographs. Subjects selected more negative adjectives to describe photographs of the older persons than younger persons, with the old man receiving more negative responses than the old woman. Girls were as willing to associate with the older as the younger persons, but boys were much less willing to associate with the elderly.
The excess enthalpies of seven n-nonane + alcohol mixtures at 298.15 K

The excess enthalpies HE of propane + methanol, + ethanol, +n-putanol, +n-pentanol, +n-hexanol, and + n-octanol were measured at 298.15 K with an isothermal flow calorimeter with a reproducibility of better than 1 per cent. All mixed endothermically with the maximum value of HE occurring in the propane-rich region. A modified form of the Redlich-Kister equation was found to give a good fit of the skewed HE's over the entire composition range investigated.
Pedotransfer functions in soil electrical resistivity estimation

Abstract Surface electrical resistivity tomography (ERT) is recognized as a powerful non-invasive soil survey and monitoring method. Relationships between electrical resistivity (ER) and soil water contents that are needed to infer the spatial distribution of soil moisture from the ERT results, are known to reflect soil properties. However, pedotransfer relationships that relate ER, water content, and basic soil properties other than clay content have not been developed. The objective of this work was to evaluate the improvement in the estimates of ER from soil water contents if soil basic properties are included in the pedotransfer equations. Soil — coarse-loamy, siliceous, mesic Typic (or Aquic) Hapludult — was sampled in 12 locations at ten depths across a 30 × 30-m experimental site. The resistivity was measured in disturbed samples in four-electrode cells. Water content, bulk density, texture, organic carbon, and pH were measured in these samples. The coefficient and the exponent in the power law-dependence of ER on volumetric water content were approximated with linear regressions that included any number of measured soil basic properties as inputs. A total of 1024 regressions were compared using the Akaike information criterion, and the best model was found that provided the best approximation with minimum number of regression terms. Six soil textural classes were encountered in the samples. When no pedotransfer relationships were included, the R2 of the log-log relationships between ER and water content increased from 0.45 at 10 cm to 0.91 at 190 cm. Splitting the dataset into topsoil and subsoil subsets resulted in favorable pedotransfer relationships with R2 about 0.85 both in topsoil and subsoil. Bulk density, clay content, sand content and pH appeared to be influential soil properties. Overall, accuracy of relationships between soil electrical resistivity and volumetric water content at ten depths in highly heterogeneous sandy soil could be substantially improved if pedotransfer relationships were established. Future work is needed on the applicability of data obtained on repacked samples to undisturbed soils and on the selection of input variables and evaluation methods for pedotransfer electrical resistivity pedotransfer functions.
A new approach to quantifying soil temperature responses to changing air temperature and snow cover

Abstract Seasonal snow cover provides an effective insulating barrier, separating shallow soil (0.25 m) from direct localized meteorological conditions. The effectiveness of this barrier is evident in a lag in the soil temperature response to changing air temperature. The causal relationship between air and soil temperatures is largely because of the presence or absence of snow cover, and is frequently characterized using linear regression analysis. However, the magnitude of the dampening effect of snow cover on the temperature response in shallow soils is obscured in linear regressions. In this study the author used multiple linear regression (MLR) with dummy predictor variables to quantify the degree of dampening between air and shallow soil temperatures in the presence and absence of snow cover at four Greenland sites. The dummy variables defining snow cover conditions were z = 0 for the absence of snow and z = 1 for the presence of snow cover. The MLR was reduced to two simple linear equations that were analyzed relative to z = 0 and z = 1 to enable validation of the selected equations. Compared with ordinary linear regression of the datasets, the MLR analysis yielded stronger coefficients of multiple determination and less variation in the estimated regression variables.
Competition Between Sexual and Parthenogenetic Artemia: a Re-Evaluation (Branchiopoda, Anostraca)

Les Artemia obligatoirement parthenogenetiques et obligatoirement sexuees ont ete mises en competition dans des cultures en laboratoire. Les variabilites intra- en interspecifique dans les competitions entre sexuees et parthenogenetiques ont ete incorporees dans le modele experimental de meme que la variation du niveau alimentaire. Des populations sexuees du nouveau Monde (A. franciscana) ont eu le dessus sur des populations parthenogenetiques (A. parthenogenetica) dans 91 % (30/33) des essais dont on pouvait etablir le score. Cependant, quand des populations parthenogenetiques etaient opposees aux populations sexuees les plus etroitement apparentees parmi celles de l'Ancien Monde (A. tunisiana) les sexuees etaient eliminees dans 98 % (43/44) des essais a score mesurable. Ces resultats different de ceux fournis par des travaux plus anciens (Wilbur, 1971; Browne, 1980b; Michaels & Bazzaz, 1986) et montrent que l'issue de la competition sexuees-parthenogenetiques peut etre influencee par certains facteurs, incluant aussi bien les conditions d'environnement que les origines geographiques et les caracteres biologiques des populations opposees.
Nitrogen and phosphorus availability from liquid dairy manure to potatoes

The effective use of manure nutrients requires an accurate assessment of their availability to the specific crops being grown. A fertilizer equivalence approach was used to evaluate the availability of nitrogen (N) and phosphorus (P) from liquid dairy manure to potatoes in field experiments conducted in northeast Wisconsin in 2000, 2001, and 2002. Crop responses to moderate and high rates of liquid dairy manure (93,500 and 187,000 L ha−1) were compared to results obtained from N or P fertilizer applied at five rates (0 to 269 kg ha−1). Availability estimates were made using the fertilizer equivalence method based on tuber yield, harvested tuber N or P concentration and uptake, petiole nitrate or total P concentration, and soil nitrate or extractable P phosphate levels. Results showed an apparent availability of manurial N from 10% to 40%, with an overall average across all 3 years and all parameters of 28.6% for the lower rate and 24.6% for the high rate. These values are slightly less than average availability measured where corn has been used as the test crop. Although all parameters did not show responses to P fertilizer additions in these trials, where estimates were possible, P availability ranged from 20% to 90% with an overall average across all 3 years of 55.4% for the low and 50.5% for the high manure rates. Despite potato being more shallow-rooted and somewhat less efficient in N and P use compared to corn, it appears that only minor adjustments to manurial nutrient availability estimates are warranted when potatoes are grown.
Mycophenolic acid glucuronide is transported by multidrug resistance-associated protein 2 and this transport is not inhibited by cyclosporine, tacrolimus or sirolimus

1. The purpose of this study was to investigate the contribution of MRP2 to the efflux of mycophenolic acid (MPA), and its phenyl glucuronide (MPAG) and acyl glucuronide (AcMPAG) metabolites, using Madin-Darby canine kidney II cells stably transfected with human MRP2 gene (MDCKII/MRP2 cells).2. Compared to parental MDCKII cells, MPAG was significantly translocated from basolateral (BL) to apical (AP) side in MDCKII/MRP2 cells, indicating MPAG is a substrate for MRP2. AcMPAG is highly translocated from BL to AP side in both cells, suggesting that AcMPAG is actively secreted possibly through an efflux transporter other than MRP2. Appreciable translocation of MPA was not observed in MDCKII/MRP2 cells.3. Furthermore, using MRP2-expressing Sf9 membrane vesicles, the Michaelis-Menten constant (Km) value for MRP2-mediated MPAG transport was calculated at 224.2 ± 42.7 µM. In the vesicle system, cyclosporine, tacrolimus and sirolimus did not inhibit the uptake of MPAG via MRP2.4. These findings indicate that only ...
Optimal scanning filters using spectral reflectance information

The quality of color correction is dependent upon the filters used to record the image. The problem of estimating, CIE tristimulus vectors of the original image under several illuminants, from data obtained with a single imaging illuminant is discussed. Optimal filters are derived which minimize the total color correction mean square error for several viewing illuminants. The sensitivity of the filters to perturbations is investigated. Simulations are performed using real reflectance spectra.
Pharmacokinetic characterization of the postdistribution phase of prohormone atrial natriuretic peptides amino acids 1-98, 31-67, and atrial natriuretic factor during and after rapid right ventricular pacing in dogs.

Release rate constants and disappearance rate constants were determined for three atrial natriuretic peptides consisting of amino acids 1–98 (i.e., proANF 1–98), the midportion of the ANF prohormone consisting of amino acids 31–67 (i.e., proANF 31–67) and amino acids 99–126 (i.e., ANF) after right ventricular pacing at 100, 125, 150, and 180 bpm in six male mongrel dogs. Right atrial and femoral vein blood was obtained at baseline, and at 5, 12, 19, 26, 56, 86, 116, 146, and 206 minutes after right ventricular pacing. Resulting plasma concentration-time data derived parameters were compared. The disappearance rate constants for atrial and femoral venous proANF 1–98 were 0.0144 ± 0.0087 (X ± SD) and 0.0175 ± 0.0075 min−1, respectively (t = 0.6158) and release rate constants were 0.1569 ± 0.1504 and 0.0670 ± 0.0393 min−1, respectively (t = 1.8269; P > .05). The proANF 31–67 disappearance rate constants were 0.0139 ± 0.0082 and 0.0148 ± 0.0132 min−1, respectively (t = 0.1192) and release rate constants were 0.0957 ± 0.0414 and 0.1984 ± 0.1762 min−1, respectively (t = 1.4812). The ANF elimination phase disappearance rate constants were 0.0663 ± 0.0273 and 0.1116 ± 0.0539 min−1 (t = 2.0923, P > .05), respectively, and the release rate constants were 0.1335 ± 0.0532 and 0.1638 ± 0.0520 min−1 (t = 0.7878, P > .05), respectively. These data indicate that proANF 1–98 and proANF 31–67 circulating β post-distribution half-lives are approximately 45 minutes whereas β half-life of ANF is 10 minutes. Persisting concentrations of proANF 1–98 and proANF 31–67 in plasma may better explain the proported sustained pharmacologic effects that have been attributed to ANF, which has a mean a distribution phase half-life of 3.5 minutes and a β half-life of 10 minutes.
Engineering responsive mechanisms to control the assembly of peptide-based nanostructures

Complex biological machines arise from self-assembly on the basis of structural features programmed into sequence-specific macromolecules (i.e. polypeptides and polynucleotides) at the molecular level. As a consequence of the near-absolute control of macromolecular architecture that results from such sequence specificity, biological structural platforms may have advantages for the creation of functional supramolecular assemblies in comparison with synthetic polymers. Thus biological structural motifs present an attractive target for the synthesis of artificial nanoscale systems on the basis of relationships between sequence and supramolecular structure that have been established for native biological assemblies. In the present review, we describe an approach to the creation of structurally defined supramolecular assemblies derived from synthetic α-helical coiled-coil structural motifs. Two distinct challenges are encountered in this approach to materials design: the ability to recode the canonical sequences of native coiled-coil structural motifs to accommodate the formation of structurally defined supramolecular assemblies (e.g. synthetic helical fibrils) and the development of methods to control supramolecular self-assembly of these peptide-based materials under defined conditions that would be amenable to conventional processing methods. In the present review, we focus on the development of mechanisms based on guest–host recognition to control fibril assembly/disassembly. This strategy utilizes the latent structural specificity encoded within sequence-defined peptides to couple a conformational transition within the coiled-coil motifs to incremental changes in environmental conditions. The example of a selective metal-ion-induced conformational switch will be employed to validate the design principles.
Remarkable Salinity Tolerance of Seven Species of Naked Amoebae (gymnamoebae)

The salinity tolerance of naked amoebae collected from sites ranging from ca. 0‰ to 160‰ were compared in laboratory experiments. Amoebae were collected from hypersaline ponds around the perimeter of the Salton Sea, California, where salinities averaged 160‰, and directly from the shoreline waters of the Sea where salinities were generally between 44 and 48‰. Naked amoebae were also collected from the intertidal zone of a Florida beach, a habitat subject (on occasion) to salinity fluctuations within the range 6–85‰. From these combined sites, 6 clones of amoebae were isolated for salinity tolerance experiments (2 marine beach isolates, 2 Salton Sea isolates, and 2 hypersaline pond isolates). A seventh clone, Acanthamoeba polyphaga, a common freshwater/soil amoeba, was obtained from a Culture Collection. Laboratory experiments compared the effects of gradually changing culture salinity versus no salinity acclimatization. Growth rate and culture yield were used as indices of effect. Generally, amoebae were tolerant over a wide range of salinity conditions (in terms of growth and yield) and were not markedly influenced by pre-conditioning to salinity changes throughout the experiments. Overall, the freshwater amoeba Acanthamoeba grew between 0 and 12‰, the marine clones grew in the range of 2–120‰, and the Salton Sea clones reproduced between 0 and 138 ‰. The hypersaline clones were the most resilient and grew between 0 and 270‰ salt. The survival and activity of large populations of naked amoebae in sites subject to salinity fluctuations suggest that they should be considered in future studies to better understand their, as yet, undefined ecological role.
The CHRNA5–A3–B4 gene cluster in nicotine addiction

Nicotine addiction (NA) is a common and devastating disease, such that the annual number of deaths (world-wide) from tobacco-related diseases will double from 5 million in the year 2000 to 10 million in 2020. Nicotine is the only substance in tobacco which animals and humans will self-administer. NA, as a lifetime diagnosis, has been assessed in various approaches, including the concept of cigarettes per day (CPD). Other assessments of NA are somewhat more comprehensive, such as the Fagerstrom Test for Nicotine Dependence or the American Psychiatric Association's Diagnostic and Statistical Manual (fourth edition) diagnosis of nicotine dependence. These different measures have moderate agreement with one another. Twin, family and adoption studies have shown that these different assessments of NA have substantial heritability (that fraction of risk attributable to genetic factors). The heritability of NA has been estimated at 50-75%, depending on the definition and the population under study. DNA-based studies of NA have been somewhat successful in identifying a common haplotype, which increases risk for NA among European-origin populations. This haplotype explains a small amount of variance, accounting for ∼1 CPD, and it includes the α5 and the α3 nicotinic receptor subunit genes (CHRNA5 and CHRNA3). The review will focus on this implicated region. In this risk region, there is a common (among European-origin people) mis-sense single-nucleotide polymorphism in the CHRNA5 gene (D398N), which changes a conserved amino acid from aspartic acid to asparagine. The risk allele (398N) confers decreased calcium permeability and more extensive desensitization, according to in vitro cellular studies, raising the possibility that a positive allosteric modulator of the (α4β2)(2)α5 type of nicotinic receptor might have therapeutic potential in NA. There are other genetic influences on NA in this region, apart from the mis-sense variant, and additional biological experiments must be done to understand them.
Investigations of Coherent Vibrational Oscillations in Myoglobin

The technique of femtosecond coherence spectroscopy (FCS) is applied to the heme protein myoglobin. Photostable samples of deoxy myoglobin (Mb) and photochemically active samples of the nitric oxide adduct (MbNO) are investigated. The pump-induced change in the probe transmittance for both samples displays coherent oscillations that, when transformed into the frequency domain, are in agreement with the resonance Raman spectrum of deoxy Mb. This indicates that the coherences associated with the photoreactive sample (MbNO) arise from the rapidly changing forces appearing in the crossing region(s) between the reactant and product state potential energy surfaces. The relative phase and amplitude of the Fe−His vibration, associated with the sole covalent linkage between the heme and the protein, are analyzed as a function of sample state and pump/probe carrier frequency. The dependence of the phase on carrier frequency is found to be significantly different for the “field driven” coherence in Mb and the “react...
A Nonradioactive Replacement for the Sodium-24 Tracer in Turbine Performance Tests

In the past, expensive measuring devices were used to determine performance and efficiency on nuclear turbine cycles. More recently, sodium-24 replaced these devices because of the reduced cost, increased accuracy and improved precision. While radioactive sodium-24 has significant advantages, it brings with it several disadvantages such as:1. limited useful working time,2. exposure of testing personnel to ionizing radiation,3. limited availability,4. the need for government licensing which for all practical purposes precludes its use in fossil plants,5. unacceptable radioactive release to the environment during boiler blow-down,6. complex analysis procedure.Thus, a nonradioactive replacement for sodium-24 has become economically desirable as well as necessary from the ease of use point of view.In this paper, the procedure for choosing a nonradioactive replacement tracer will be discussed with reference to the criteria needed to be satisfied for an adequate tracer e.g., a suitable and sensitive analytical detection technique that would be already available to power plants. Necessary refinements to the sodium-24 testing procedure will also be discussed as well as a unique means of preconcentrating the tracer prior to analysis. The laboratory evaluation and method development to be discussed in the paper was funded by EPRI.The potential applications for the new tracer, which include all sodium-24 uses, will be noted. These uses include, but are not limited to component performance, heater leakage, and moisture calculations. Because federal licensing of the nonradioactive tracer is not necessary, tests in a fossil plant are possible and will also be discussed.The completed laboratory experiments indicate high promise for success in actual field tests which are scheduled for mid-1984 for fossil plant testing, and mid-1985 for nuclear station testing.Copyright © 1984 by ASME
Differentiating manool and 13-epimanool with NMR chiral shift reagents

Abstract Use of NMR chiral shift reagents showed that a compound isolated from Pinus contorta bark and Tsuga heterophylla wood was 13-epimanool. Southern pine ( Pinus spp.) tall oil contained a mixture of manool and 13-epimanool.
An In Vivo Three-Dimensional Magnetic Resonance Imaging-Based Averaged Brain Collection of the Neonatal Piglet (Sus scrofa)

Due to the fact that morphology and perinatal growth of the piglet brain is similar to humans, use of the piglet as a translational animal model for neurodevelopmental studies is increasing. Magnetic resonance imaging (MRI) can be a powerful tool to study neurodevelopment in piglets, but many of the MRI resources have been produced for adult humans. Here, we present an average in vivo MRI-based atlas specific for the 4-week-old piglet. In addition, we have developed probabilistic tissue classification maps. These tools can be used with brain mapping software packages (e.g. SPM and FSL) to aid in voxel-based morphometry and image analysis techniques. The atlas enables efficient study of neurodevelopment in a highly tractable translational animal with brain growth and development similar to humans.
Description of and results from camera systems for recording daytime lightning strikes to an airplane in flight

Photographic still and movie and video camera systems have been developed to reveal more about the characteristics of daytime lightning strikes to airplanes in flight. Equipment selection and design is particularly important with regard to time of event occurrence, time correlation between cameras, rapidity of actuation, ease of photogrammetric analysis, and selection of fields of view. The most recent such camera systems flown in an NASA F-106B research airplane are described and design considerations are discussed. Daytime depictions of lightning strikes are presented as illustrative of some of these considerations.
Liver-specific deletion of the growth hormone receptor reveals essential role of growth hormone signaling in hepatic lipid metabolism

Growth hormone (GH) plays a pivotal role in growth and metabolism, with growth promotion mostly attributed to generation of insulin-like growth factor I (IGF-I) in liver or at local sites of GH action, whereas the metabolic effects of GH are considered to be intrinsic to GH itself. To distinguish the effects of GH from those of IGF-I, we developed a Cre-lox-mediated model of tissue-specific deletion of the growth hormone receptor (GHR). Near total deletion of the GHR in liver (GHRLD) had no effect on total body or bone linear growth despite a >90% suppression of circulating IGF-I; however, total bone density was significantly reduced. Circulating GH was increased 4-fold, and GHRLD displayed insulin resistance, glucose intolerance, and increased circulating free fatty acids. Livers displayed marked steatosis, the result of increased triglyceride synthesis and decreased efflux; reconstitution of hepatic GHR signaling via adenoviral expression of GHR restored triglyceride output to normal, whereas IGF-I infusion did not correct steatosis despite restoration of circulating GH to normal. Thus, with near total absence of circulating IGF-I, GH action at the growth plate, directly and via locally generated IGF-I, can regulate bone growth, but at the expense of diabetogenic, lipolytic, and hepatosteatotic consequences. Our results indicate that IGF-I is essential for bone mineral density, whereas hepatic GH signaling is essential to regulate intrahepatic lipid metabolism. We propose that circulating IGF-I serves to amplify the growth-promoting effects of GH, while simultaneously dampening the catabolic effects of GH.
Geometric variability of raster cell class assignment

Applications like land-cover mapping frequently require the transformation of vector polygons to raster grids, such that each cell in the output raster is assigned a single class. Cell value assignment is a direct function of the geometric relationship between the vector polygons and the origin, orientation and spatial resolution of the raster structure, acting in conjunction with the value assignment rule employed by the algorithm. Results of an alternative approach to characterizing origin assignment variability are reported. A simulation approach is employed to perturb the origin of the grid lattice by amounts smaller than the grid spacing. The distribution of results across all output raster realizations indicates the rasterization variability for a particular input vector map at a particular cell size. Results for a representative vector land-cover dataset are presented, indicating that substantial variability is possible. The paper concludes with a discussion of theoretical and practical implication...
Developmental analysis of activin-like kinase receptor-4 (ALK4) expression in Xenopus laevis.

The type I transforming growth factor-beta (TGFβ) receptor, activin-like kinase-4 (ALK4), is an important regulator of vertebrate development, with roles in mesoderm induction, primitive streak formation, gastrulation, dorsoanterior patterning, and left–right axis determination. To complement previous ALK4 functional studies, we have analyzed ALK4 expression in embryos of the frog, Xenopus laevis. Results obtained with reverse transcriptase-polymerase chain reaction indicate that ALK4 is present in both the animal and vegetal poles of blastula stage embryos and that expression levels are relatively constant amongst embryos examined at blastula, gastrula, neurula, and early tail bud stages. However, the tissue distribution of ALK4 mRNA, as assessed by whole-mount in situ hybridization, was found to change over this range of developmental stages. In the blastula stage embryo, ALK4 is detected in cells of the animal pole and the marginal zone. During gastrulation, ALK4 is detected in the outer ectoderm, involuting mesoderm, blastocoele roof, dorsal lip, and to a lesser extent, in the endoderm. At the onset of neurulation, ALK4 expression is prominent in the dorsoanterior region of the developing head, the paraxial mesoderm, and midline structures, including the prechordal plate and neural folds. Expression in older neurula stage embryos resolves to the developing brain, somites, notochord, and neural crest; thereafter, additional sites of ALK4 expression in tail bud stage embryos include the spinal cord, otic placode, developing eye, lateral plate mesoderm, branchial arches, and the bilateral heart fields. Together, these results not only reflect the multiple developmental roles that have been proposed for this TGFβ receptor but also define spatiotemporal windows in which ALK4 may function to modulate fundamental embryological events. Developmental Dynamics 232:393–398, 2005. © 2004 Wiley-Liss, Inc.
The evolving instability of the remnant Larsen B Ice Shelf and its tributary glaciers

Abstract Following the 2002 disintegration of the northern and central parts of the Larsen B Ice Shelf, the tributary glaciers of the southern surviving part initially appeared relatively unchanged and hence assumed to be buttressed sufficiently by the remnant ice shelf. Here, we modify this perception with observations from IceBridge altimetry and InSAR-inferred ice flow speeds. Our analyses show that the surfaces of Leppard and Flask glaciers directly upstream from their grounding lines lowered by 15 to 20 m in the period 2002–2011. The thinning appears to be dynamic as the flow of both glaciers and the remnant ice shelf accelerated in the same period. Flask Glacier started accelerating even before the 2002 disintegration, increasing its flow speed by ∼55% between 1997 and 2012. Starbuck Glacier meanwhile did not change much. We hypothesize that the different evolutions of the three glaciers are related to their dissimilar bed topographies and degrees of grounding. We apply numerical modeling and data assimilation that show these changes to be accompanied by a reduction in the buttressing afforded by the remnant ice shelf, a weakening of the shear zones between its flow units and an increase in its fracture. The fast flowing northwestern part of the remnant ice shelf exhibits increasing fragmentation, while the stagnant southeastern part seems to be prone to the formation of large rifts, some of which we show have delimited successive calving events. A large rift only 12 km downstream from the grounding line is currently traversing the stagnant part of the ice shelf, defining the likely front of the next large calving event. We propose that the flow acceleration, ice front retreat and enhanced fracture of the remnant Larsen B Ice Shelf presage its approaching demise.
Double predictor differential pulse code modulation algorithm for image data compression

A new algorithm for designing differential pulse code modulation (DPCM) systems is presented for image data compression. When transmitting images over noiseless channels, the distortion between the original and reconstructed images results primarily from quantization noise. This is true when optimal predictor structures are employed. The quantization error becomes severe at low bit rates. This is because of the large quantization error being directly fed back into the predictor and used in subsequent estimation of future pixels. The DPCM scheme developed attempts to balance between nonoptimal predictor designs and significantly reduced feedback effects resulting from quantization errors with the objective of maximizing reconstructed image quality. DPCM system performance using the algorithm is about 2.5 dB greater than that obtained from an optimally designed conventional system. In addition, the algorithm is robust. Thus, the DPCM predictor does not need to be redesigned using exact statistics of the input image data for each image to be transmitted.
Transition to the clinical doctorate: attitudes of the genetic counseling training program directors in North America.

In North America, genetic counseling is an allied health profession where entry level practitioners currently must hold a master’s degree earned from a graduate program accredited by the American Board of Genetic Counseling. This is one of many health care professions that could transition to an entry level clinical doctorate degree. This study explored the attitudes of genetic counseling training program directors toward such a transition. Thirty-one North American program directors were invited to complete an online survey and a follow-up telephone interview. Twenty-one program directors completed the survey and ten directors also completed a follow up phone interview. There was disagreement among the respondents on the issue of transitioning to a clinical doctorate degree (nine in favor, six against and six undecided). Respondents disagreed about whether the transition would lead to higher salaries (six yes, eight no, and seven unsure) or increased professional recognition (eight yes, eight no, and four unsure). Approximately half (n = 10) of directors were not sure if the transition to a clinical doctorate would help or hurt minority recruitment; six thought it would help and four thought it would hurt. However, the majority (n = 13) thought a clinical doctorate would help genetic counselors to obtain faculty positions. If the field transitions to a clinical doctorate, 11 of the directors thought their program would convert, seven were unsure and one thought their program would shut down. Themes identified in interview data included 1) implications for the profession 2) institution-specific considerations and 3) perception of the unknown. Opinions are quite varied at this time regarding the possible transition to the clinical doctorate among genetic counseling training program directors.
Cerebellum plus locus coeruleus in tissue culture: I. Catecholamine histofluorescence and extracellular electrophysiology

Neonatal mouse cerebellar cultures with incorporated dorsal pons contained groups of catecholamine histofluorescent locus coeruleus neurons that projected axons to cerebellar cortical regions. Electrical stimulation of local areas of the dorsal pontine fragments evoked complex inhibitory extracellular cortical responses that resembled cerebellar cortical responses to locus coeruleus stimulation in vivo. The apparent structural and functional integrity of the coeruleo-cerebellar system in tissue culture indicates that this model might reasonably be used for biochemical studies of catecholamine development and metabolism.
Trends in prenatal ultrasound use in the United States: 1995 to 2006.

Background:While controversy continues about the appropriateness of routine ultrasound screening, there are little data on actual clinical practices or trends in the United States.Objectives:To examine changes in prenatal ultrasound utilization over time and determine whether ultrasound utilization
Regularization technique for restoration of x-ray fluoroscopic images

X-ray fluoroscopic images are degraded by x-ray scattering within the subject and veiling glare in the image intensifer. Densitometric accuracy is further degraded by beam hardening. Scattering, veiling glare, or both are modeled as a blurred representation of the primary image plus an offset. If the image can be represented by convolution of the primary with a known response function, then an estimate of the primary component of the image can be computed by deconvolution. We describe a technique for estimating a parameterized response function so that a good estimate of the subject density profile can be recovered even if the response function parameters are not known in advance. This is important for x-ray imaging (particularly fluoroscopy) since the acquisition parameters are variable. A reference object designed to be uncorrelated with the subject is imaged in superposition with the subject. The unknown parameters are then adjusted to minimize a cost function subject to the constraint that the correlation between the known reference density and the estimated subject density be zero. The method can be extended to include a correction for beam hardening.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
DNA fragmentation indicative of apoptosis following unilateral cerebral hypoxia-ischemia in the neonatal rat

DNA extracted from regional brain samples of hypoxic/ischemic neonatal rats showed internucleosomal cleavage indicative of apoptosis. Cells containing cleaved DNA were identified by in situ labelling in the cortex, hippocampus, striatum and thalamus of the ipsilateral hemisphere. When the effects of increasing the length of the hypoxia were examined, increases were seen in the amount of internucleosomally cleaved DNA and in the number of labelled cells.
Polypeptide Activators of Cholesterol Side-Chain Cleavage

A rate-determining step in the cAMP-dependent action of ACTH on adrenal steroid biosynthesis is the interaction of cholesterol substrate with the cholesterol side-chain cleavage cytochrome P-450 in the mitochondrion. This interaction is rapidly and reversibly sensitive to inhibitors of protein synthesis. For this reason a hormone-dependent, labile protein activator of cholesterol side-chain cleavage has long been postulated as an obligatory intermediate in the tropic regulation of this reaction. Applying recent advances in liquid chromatography, two-dimensional gel electrophoresis, and enzyme reconstitution into liposomes, several laboratories have now reported the isolation and partial characterization of polypeptide candidates for the status of "labile protein."
Recurrence of Adrenal Cortical Carcinoma Following Resection: Surgery Alone Can Achieve Results Equal to Surgery Plus Mitotane

A recent nonrandomized interinstitutional study reported that adjuvant mitotane following surgery for adrenocortical carcinoma (ACC) was associated with decreased recurrence. Because of the limitations of this study, we investigated the influences of surgery and adjuvant mitotane in a large series of ACC patients evaluated and treated at a single referral center. Retrospective evaluation of patients followed at a single institution after surgery for ACC. 218 patients with ACC underwent primary resection either at the index institution [surgery index (SI), n = 28] or an outside institution [surgery outside (SO), n = 190] and had a median follow-up of 88 months. SI patients had a superior disease-free survival compared with SO patients (median 25 versus 12 months, P = 0.003), and SI patients also had a superior overall survival compared with SO patients (median not reached versus 44 months, P = 0.02). Factors predicting increased risk of recurrence on multivariate analysis were surgery at an outside institution [hazard ratio (HR) 2.56, 95% confidence interval (CI) 1.44–4.53, P = 0.001] and no treatment with adjuvant mitotane (HR 1.95, 95% CI 1.06–3.59, P = 0.03), and those predicting a poorer survival were advanced stage at presentation (P = 0.01) and surgery at an outside institution (HR 2.62, 95% CI 1.31–5.25, P = 0.007). The recurrence rate of the index group (50%) in the current series, the overwhelming majority of whom did not receive adjuvant mitotane, is indistinguishable from that reported for those who received adjuvant mitotane (49%) in the recent interinstitutional report, emphasizing the importance of completeness of initial surgery in the management of patients with ACC.
Effects of 10-(2-propynyl)-estr-4-ene-3,17-dione (MDL 18,962)--a mechanism-based irreversible inhibitor of aromatase--in cultured human foreskin fibroblasts.

Abstract In male subjects, peripheral aromatization of androgens accounts for most of the estrogen production, and skin is an important site of such enzymatic activity. We have studied the effects of a mechanism-based, irreversible aromatase inhibitor, 10-(2-propynyl)-estr-4-ene-3,17-dione (MDL 18,962) on androgen action and metabolism in cultured human foreskin fibroblasts. Cells were incubated simultaneously in the presence of substrate, androstenedione, and inhibitor, MDL 18,962. Aromatase activity was linear with time up to 3 h of incubation at 37°C in the absence and presence of 1.0–10nM inhibitor. The IC50 for four different cell strains ranged from 4.0 to 8.6 nM MDL 18,962. Kinetic analysis of competitive inhibition by the Eadie-Hofstee method yielded an apparent Ki of 2.75 nM for the inhibitor Preincubation of cells with MDL 18,962 resulted in irreversible inhibition of aromatase activity which was time- and concentration-dependent. We calculated a Ki of 7.6 nM for MDL 18,962. Preincubation of cells with 25 nM MDL 18,962 suppressed enzyme activity for up to 6 h following removal of the inhibitor, before a return of enzyme activity due to synthesis of new enzyme. MDL 18,962 (0.2–20μM) did not influence the 5α -reduction of testosterone (200 nM). In addition, binding of dihydrotestosterone (2nM) to androgen receptors was not affected by MDL 18,962 (25–1000 nM). In summary, MDL 18,962 is a specific, high potency inhibitor of aromatase. By virtue of its high binding affinity to the enzyme active site, it competes very effectively with substrate, resulting in irreversible inactivation of aromatase.
Insulin Secretion and Sensitivity in Healthy African-American vs American White Children

Racial differences in insulin secretion and insulin sensitivity in healthy children were studied by administering a 2-hour hyperglycemic clamp (225 mg/dL) to 14 black and 16 white healthy adolescents (Tanner II-V), and 12 black and 11 white prepubertal children, matched for age, body mass index, and Tanner I pubertal development. In prepubertal children, fasting and first-phase insulin concentrations were higher in blacks compared with whites (14.7+/-1.3 vs 10.4+/-1.2, P=0.02, and 76.9+/-6.8 vs 52.1+/-6.4 microu/mL, P=0.016). There were no differences in second-phase insulin levels and insulin sensitivity index. In pubertal adolescents, first-phase and second-phase insulin concentrations were higher in blacks compared with whites (first-phase: 157.3+/-18.3 vs 77.0+/-8.7 microu/mL, P=0.0003; second-phase: 175.0+/-24.3 vs 108.7+/-8.8 microu/mL, P=0.012). Insulin sensitivity index was 35% lower in black adolescents compared with whites (P=0.02). These findings indicate that significant differences in insulin secretion and sensitivity are detectable early in childhood in healthy African-American vs American whites. However, genetic (race) vs environmental factors (physical activity/fitness, energy balance) should be carefully scrutinized as potential factors responsible for such differences.
Velocity of Electric Currents

WHILE the velocity of electric waves is well known, as Maxwell and Heaviside have pointed out, we know absolutely nothing of the velocity with which electricity travels in a wire. As Heaviside says (“Papers”, vol. ii., p. 3, line 4):—“It may be an inch an hour or it may be immensely great”.
Enhancing effects of manufacturing flexibility through operational absorptive capacity and operational ambidexterity

Abstract A large body of research investigates how manufacturing flexibility in uncertain environments leads to firm performance, with mixed results. The mixed findings could be due to differences across firms in terms of the capabilities to acquire, assimilate, and transform knowledge and to simultaneously pursue both the exploitation of existing operational capabilities and the exploration for new operational capabilities. Building on the literature that suggests that manufacturing flexibility mediates the relationship between environmental uncertainty and firm performance, we explore the applicability of two organizational learning contingencies to the operations environment: operational absorptive capability and operational ambidexterity. Absorptive capacity enables the recognition and assimilation of new knowledge. Ambidexterity determines whether this knowledge will be applied for both exploration and exploitation. Using a sample of 852 manufacturing firms, we find that environmental uncertainty affects firm performance directly and indirectly through manufacturing flexibility. Furthermore, both operational absorptive capacity and operational ambidexterity moderate the relationship between environmental uncertainty and manufacturing flexibility and the relationship between manufacturing flexibility and firm performance. Theoretical and practical implications are discussed.
Differences in secretion of prostacyclin by venous and arterial endothelial cells grown in vitro in a static versus a mechanically active environment.

Abstract The objective of this study was to compare the effect of cyclic tension on prostacyclin secretion by venous and arterial endothelial cells. Early passage endothelial cells from bovine aortas and venae cavae were subjected to cyclic deformation (up to 17% elongation and 60 cycles/min). On posttreatment days 3 and 5 a radioimmunoassay was used to assess supernatant fluids from the endothelial cells for prostacyclin activity. The results indicate that in vitro (1) under static or control conditions, venous endothelial cells secrete significantly more prostacyclin (an increase of 1.5- and 4.8-fold on days 3 and 5, respectively) than do arterial endothelial cells isolated from the same animal and (2) prostacyclin secretion by mechanically deformed venous and arterial endothelial cells was significantly less than static control cultures on days 3 and 5. However, prostaglandin I 2 secretion remained at higher levels in cyclically deformed venous endothelial cells than in cyclically deformed arterial endothelial cells. These data suggest that endothelial cells from the vena cava have a greater capacity for prostacyclin secretion than have their aortic counterparts. If these observations are maintained in vivo, greater prostacyclin secretion by venous endothelial cells could represent a homeostatic mechanism aimed at reducing thrombus formation in low-velocity areas of the vasculature. (J Vasc Surg 1989;10:292–8.)
Parasternal Intrapleural Colon Interposition: An Alternative Pathway for the Colon Graft

A new pathway for the placement of the interposed colon in esophagocolonoplasty is described. In a patient with a peptic stricture and a history of previous coronary artery bypass operation and multiple thoracotomies, the interposed colon was placed in the parasternal right intrapleural space successfully. This avoided a thoracotomy as well as the areas of adhesion. Technical details are described.