cssi/SciSciGPT-SciSciNet huggingface dataset:
Mechanisms and Regulation of the Gene-Expression Response to Sepsis

Sepsis is defined as the systemic inflammatory response of the human host that is triggered by an invading pathogen. Despite tremendous advances in both our knowledge of and treatment strategies for this syndrome, sepsis remains among the major causes of morbidity and mortality in children worldwide. Thus, we hypothesize that an improved mechanistic understanding obtained via basic and translational science will continue to identify novel therapeutic targets and approaches. As a result, given the central importance of the alterations in gene expression in regulating the human host’s physiologic response to a pathogen, we review those complex factors: genetics, transcriptional expression and epigenetics, which regulate unique gene expression patterns in pediatric sepsis and septic shock. We anticipate that emerging data from genetic, genomic and other translation studies in pediatric sepsis will advance our biologic understanding of this response and undoubtedly identify targets for newer therapies.
Comparison of CT and MRI brain tumor imaging using a canine glioma model

A canine gliosarcoma model was used to study the effectiveness of magnetic resonance imaging (MRI) with gadolinium contrast enhancement in defining the histologic margins of brain tumors. The effectiveness of this technique was compared to conventional computed tomography (CT) using iodinated contrast enhancement. Cultured canine gliosarcoma cells were injected into the left hemisphere of adult mongrel dogs. The dogs developed brain tumors and progressive clinical signs. Serial MRI with and without gadolinium diethylene triamine penta-acetic acid was compared to serial CT with and without sodium iothalamate obtained on the same days. After the final scans, animals were sacrificed; the brains were removed and processed for routine histopathologic study. All tumors were visualized with contrast-enhanced MRI which proved most sensitive. Gadolinium di-ethylene triamine penta-acetic acid caused bright enhancement of tumors in a distribution that consistently corresponded to areas of pathologically proved tumor infiltration. Gross and microscopic autopsy findings correlated better with MRI than with CT which tended to produce poorer resolution and underrepresent the size of viable tumor. Gadolinium-enhanced MRI is more accurate than unenhanced MRI, unenhanced CT, or enhanced CT in defining the histologic margins of tumors.
Evolving Social Media into Productivity Platforms

Social media have become a global phenomenon affecting people in their private lives and in their personal interactions, particularly among younger people. It is thus not surprising that social media are also being explored in professional contexts such as in large enterprises, where a number of social media platforms and social extensions to existing workgroup and collaboration systems have been emerging. In this paper, we consider one such platform that was developed for the internal use in a large global enterprise. We present data and their analysis for how this social media platform has been used in HP over the past five years. We then present conclusions from this analysis and relate them to work patterns in enterprises with the goal to better adapt social media platforms to the enterprise domain such that they better integrate with the work context people have as well as with IT systems that are used by them. The contribution of the paper is two-fold. First, we present data and usage analysis of our social media platform over the past five years. Second, based on this analysis, we derive enhancements for social media platforms to better fit the work context and that can turn social media into a new generation of productivity platforms for the enterprise.
Identifying technology investments for future space missions

In this paper, a systems engineering model is presented that identifies the technologies that proide the most significant impact for a given mission.
Sensitivity Analysis Revisted and Extended

The tolerance approach to sensitivity analysis in linear programming provides a framework for dealing with simultaneous and independent variations of the coefficients and terms. Specifically, the approach yields a maximum tolerance percentage which in turn characterizes a region of variability for the coefficients or terms. This paper shows how to expand this region of variability yielding ordinary sensitivity analysis as a special case of the tolerance approach.
A conversation about computer science education

This discussion began as an invitation to comment on the advisability of replacing some of the study of data structure implementation in CS2. It broadened into a discussion of a number of other aspects of computer science education. Dennis Frailey writes from an industrial point of view, although he also teaches computer science on an adjunct basis and was once a full-time academic. Dan McCracken writes from an academic point of view, although he has also worked in industry.
Determination of the whole set of elastic constants of a polymeric Langmuir-Blodgett film by Brillouin spectroscopy.

On presente des experiences de diffusion de lumiere de Brillouin sur des films de Langmuir. Blodgett uniaxiaux polymeriques ayant leur axe preferentiel, l'axe c, dans le plan du film. On observe a la fois des modes de surface et de volume acoustiques. A partir des spectres on determine l'ensemble complet des constantes elastiques ainsi que les indices de refraction. Pour des echantillons ayant plus de dix monocouches moleculaires, les constantes elastiques ne dependent pas de l'epaisseur du film. Le rapport entre les vitesses de son transverses et longitudinales est inferieur a celui des solides ordinaires
Performance and Capacity of Direct-Sequence Spread Spectrum Overlay in the Microwave Landing System Band

We examine the performance of a direct-sequence spread spectrum (DS-SS) code-division multiple-access (CDMA) system used in a spectral overlay mode in the Microwave Landing System (MLS) band, from 5091–5150 MHz. The purpose of the overlay system is to enable increased spectral efficiency (higher data throughput), for future potential aeronautical datalink communications, particularly for short-range systems such as for airport surface, and terminal areas. We estimate the performance degradation incurred by both systems for a range of relative transmit powers, several DS-SS bandwidths and data rates, and example MLS and DS-SS system parameters, including the number of DS-SS users. We also briefly examine the use of multicarrier (MC) DS-SS signaling techniques. Our study uses both analysis and computer simulations, and complements prior work done for the use of DS-SS in the Instrument Landing System Glideslope band, where the ILS signal is an analog signal, in contrast to the (analog and) digital MLS signal. We provide examples that explore both MLS and DS-SS system parameter values appropriate for the successful application of overlay.
Identification of She3 as an SCFGrr1 Substrate in Budding Yeast

The highly orchestrated progression of the cell cycle depends on the degradation of many regulatory proteins at different cell cycle stages. One of the key cell cycle ubiquitin ligases is the Skp1-cullin-F-box (SCF) complex. Acting in concert with the substrate-binding F-box protein Grr1, SCFGrr1 promotes the degradation of cell cycle regulators as well as various metabolic enzymes. Using a yeast two-hybrid assay with a Grr1 derivative as the bait, we identified She3, which is an adaptor protein in the asymmetric mRNA transport system, as a novel Grr1 substrate. We generated stabilized She3 mutants, which no longer bound to Grr1, and found that the degradation of She3 is not required for regulating asymmetric mRNA transport. However, She3 stabilization leads to slower growth compared to wild-type cells in a co-culture assay, demonstrating that the degradation of She3 by Grr1 is required for optimal cell growth.
Gamma-ray pulse-height response of an NE-213 scintillation detector

Abstract Gamma-ray response functions were measured for an NE-213 scintillation detector using a superconducting electron microtron with a bremsstrahlung monochromator which provided over 100 monoenergetic gamma-ray sources between 2 and 11.5 MeV. The absolute measurements were used to construct a gamma-ray response matrix to unfold NE-213 gamma-ray pulse-height data. The energy spectra of gamma rays from 24 Na, PuBe, and 252 Cf sources were measured and unfolded as a test of the response matrix.
Ray Shooting Amidst Convex Polygons in 2D

We consider the problem of ray shooting in a two-dimensional scene consisting ofmconvex polygons with a total ofnedges. We present a data structure that requiresO(mnlogm) space and preprocessing time and that answers a ray shooting query inO(log2mlog2n) time. If the polygons are pairwise disjoint, the space and preprocessing time can be improved toO((m2+n)logm) andO((m2+nlogn)logm), respectively. Our algorithm also works for a collection of disjoint simple polygons. We also show that if we allow onlyO(n) space, a ray shooting query among a collection of disjoint simple polygons can be answered in timeO(?m/formula]?1+?log2n) time, for any ?>0.
Voting equilibria with market-based assessments

Abstract Our model postulates that the price of a home is the capitalized value of services from its physical characteristics and local public goods less property taxes. Assuming properties are assessed at market value and that households vote so as to maximize the value of their properties, we show that if ‘tax prices’ are independent of the level of public services, the voting outcome is a Lindahl equilibrium. Even when tax prices are not constant, market value assessment reduces disagreement over the appropriate size of the local government budget.
A selective effect of p-chlorophenylalanine on fixed-ratio responding.

Abstract Rats were trained to lever press for water on an FR 20 schedule of reinforcement. Administration of p-chlorophenylalanine (two injections of 150 mg/K 24 hr apart) depleted whole brain serotonin and produced marked changes in the interresponse time distribution. p-Chlorophenylalanine had no effect on the overall rate of response, or on the frequency or duration of short interresponse times. The post-reinforcement pause was reliably lengthened by p-chlorophenylalanine. The increase in post-reinforcement pause did not appear to be due to changes in the deprivation state, since an identical drug regimen had no effect on water intake, during a free watering period, in water-deprived animals. It was suggested that the effect of p-chlorophenylalanine might be due to an increase in the aversiveness of environmental stimuli.
Inelastic collisional deactivation in plasma-related non-spectroscopic matrix interferences in inductively coupled plasma atomic emission spectrometry

Abstract Inelastic collisional deactivation of the analyte excited state is demonstrated as a dominant cause for non-spectroscopic matrix interference in inductively coupled plasma atomic emission spectrometry (ICP-AES) for commonly used plasma operating conditions in routine analysis. A mathematical simulation of the inelastic collisional model was examined. Comparison between the theoretical model and experimental results using atomic and ionic lines of the analytes Zn, Ba, Mg, Mn and Sr validates the inelastic collisional deactivation model as a dominant cause for non-spectroscopic matrix effect. Matrices evaluated were NH 4 Cl, NH 4 SCN, (NH 4 ) 2 SO 4 , and H 2 SO 4 to represent difficult-to-ionize matrices (DIE) and NaCl and CaCl 2 to represent easy-to-ionize element matrices (EIE).
Electronic states on the relaxed (110) surface of GaAs

Abstract The electronic structure of the (110) surface of GaAs is analyzed using a surface relaxation model as determined by recent low energy electron diffraction studies. A self-consistent pseudopotential calculation based on this model yields no intrinsic surface states within the fundamental band gap. Moreover, our calculations are in good agreement with recent photo-emission measurements.
Static analysis of contained fluids with potential‐based and displacement‐based fluid finite elements

We compare potential‐based (o‐U‐P0) and displacement‐based finite element methods for static analysis of contained fluids. A general transient formulation may be specialized to static analysis in both cases. In the potential‐based method velocity potentials (o) and a single pressure (P0) variable are the unknowns in the fluid region. Displacements are the unknowns in the fluid for displacement‐based methods. Higher‐order displace‐ment‐based elements may produce singular matrices for some static analyses, restricting us to four‐node elements for reliability. While both methods can yield excellent results when compared with experimental data, potential‐based methods appear to have computational advantages over displacement‐based methods.
Hemodynamic stress responses in men and women examined as a function of female menstrual cycle phase

Fifteen men and 11 normally ovulating women were each tested twice for cardiovascular stress reactivity, cognitive/behavioral performance, and mood during a variety of stressors. Each women was tested during both the follicular and luteal phase of her menstrual cycle, with men matched for number of days between testing. Although the genders did not differ in blood pressure reactivity during either phase of the cycle, during both phases of the menstrual cycle women exhibited greater heart rate reactivity and tended towards greater cardiac index increases, greater pre-ejection period decreases, and lesser vascular tone relative to men. Additionally, the menstrual cycle was observed to influence gender differences in stroke volume index responses. Specifically, stroke volume index responses for women were significantly greater in their luteal versus follicular phase resulting in a marginally significant pattern whereby women's stroke volume index responses were greater than men's luteally but less than men's follicularly. Men and women also differed in cognitive performance and mood assessment during the tasks, but the majority of these differences were unaffected by the menstrual cycle.
Pathophysiologic significance of “stress” or relative polycythemia in essential hypertension

Abstract Fourteen patients with essential hypertension (blood pressure 167 ± 2 106 ± 2 [ mean ± standard error of the mean ] mm Hg ) were studied prospectively to determine the pathophysiologic correlates of their “stress” or relative polycythemia. All patients had a high hematocrit level (53.1 ± 0.4 vol percent), contracted plasma volume (16.2 ± 0.4 ml/cm height) and normal red cell mass and serum erythropoietin levels. Blood and plasma viscosity (0.076 ± 0.005 and 0.017 ± 0.001 poise, respectively) were increased, and plasma renin activity in the supine, resting state averaged 1.8 ± 0.3 ng/ml per hour. All patients were treated with methyldopa to achieve normal arterial pressure and the previous determinations were repeated after 1 and 4 weeks of treatment. Reduction of pressure was associated with expansion of plasma volume (P
13C chemical shifts of Δ1‐pyrrolines

13C chemical shifts are reported for the ring carbons of several substituted Δ1-pyrrolines. Average values for methine and methylene ring carbons facilitate structure elucidation of substituted δ1-pyrrolines by 13C NMR spectroscopy.
Summary of: Regenerative endodontics

Background Significant advances in our understanding of the biological processes involved in tooth development and repair at the cellular and molecular levels have underpinned the newly emerging area of regenerative endodontics. Development of treatment protocols based on exploiting the natural wound healing properties of the dental pulp and applying tissue engineering principles has allowed reporting of case series showing preservation of tissue vitality and apexogenesis. Aim To review current case series reporting regenerative endodontics. Results Current treatment approaches tend to stimulate more reparative than regenerative responses in respect of the new tissue generated, which often does not closely resemble the physiological structure of dentine-pulp. However, despite these biological limitations, such techniques appear to offer significant promise for improved treatment outcomes. Conclusions Improved biological outcomes will likely emerge from the many experimental studies being reported and will further contribute to improvements in clinical treatment protocols.
Clinical experience with a high definition exoscope system for surgery of pineal region lesions

VITOM-90 (Karl Storz Endoscopy, Tuttlingen, Germany) is a new technology that can be used as an alternative to the operating microscope. We have found that this device substantially improves surgeon comfort during infra-tentorial supracerebellar approaches to pineal region masses, and now report our experiences. The VITOM-90 is a specially designed scope that is attached to a high definition (HD) digital camera and displayed on a HD video monitor. This system was utilized in five patients undergoing infratentorial supracerebellar approaches for pineal region lesions. Surgical outcomes and pathologies are described. The device was used by three surgeons during five procedures. Three patients underwent surgery in the sitting position and two in the modified prone (Concorde) position. Pathologies included pineocytoma, lipoma, and germinoma. Total resection was achieved in three patients and subtotal in two patients. Surgeon assessment was positive; surgeons indicated that surgery with the VITOM-90 was more comfortable than with the operating microscope. Lack of stereopsis was considered a minor drawback. The VITOM-90 permitted a natural head and neck position. Operating room personnel and residents reported improved visualization of the anatomy. Using the VITOM-90 benefited surgeons during pineal region surgery by reducing strain and allowing the surgeon to operate from a comfortable position without increased operative time or complications. The improved comfort levels may translate into safer, more accurate surgeries in this complex area.
Matching sequences : Cross-spectral analysis of categorical time series

SUMMARY We consider the problem of quantifying the degree to which two stationary categorical time series are coherent. The goal is to discover whether or not the sequences contain similar patterns. The problem is motivated by the problem of matching two DNA sequences. Following the ideas used in defining the spectral envelope for a qualitativevalued time series, the methods we present here focus on the problem of obtaining coherency envelopes for measuring the similarity between two categorical time series. Estimation is based on the fast Fourier transform so that the methods are computationally simple and fast, and can be applied to long sequences.
Morning-to-eveninf Change in Refraction, Corneal Curvature, and Visual Acuity 2 to 4 Years after Radial Keratotomy 1n the PERK Study

Abstract The authors previously reported morning-to-evening changes in ophthalmic measurements at 3 months and at 1-year after radial keratotomy in a self-selected group of patients in the Prospective Evaluation of Radial Keratotomy (PERK) study. Fifty-two patients included in the earlier study were examined again between 2 1/2 and 4 years after surgery before 10:00 AM and after 5:30 PM on the same day to determine if the changes persisted beyond 1 year after surgery. Between the morning and evening examinations, 31 % of the eyes had an increase in minus spherical equivalent power of the manifest refraction of 0.50 to 1.50 diopters; 12% had a change in cylinder power of 0.50 to 1.00 D; 19% had a decrease in uncorrected visual acuity of two to five Snellen lines; and 29% showed central corneal steepening by 0.50 to 1.00 D. Thus, in some patients, morning-to-evening fluctuation persisted until 2 1/2 to 4 years after radial keratotomy.
Isotope label scrambling in alkyl cations. A mechanistic proposal

The observation of sharp limits to the chain lengths of alkyl cations derived by low energy collision-induced dissociation of isotopically labelled trimethyltetradecylammonium cations, as well as the selectively limited scrambling of its isotope label, has prompted the proposal of a new mechanistic model for alkyl cation fragmentation. The model invokes protonated cyclopropane intermediates which may reopen to branched structures, or fragment (if suitably substituted) to form smaller alkyl cations and neutral olefins. The model accounts completely for the absence of daughter ions with fewer than three or more than six carbon atoms, while its semi-quantitative application provides a reasonable match to the observed isotope scrambling.
The iconography of the tourism experience

Abstract Guides to tourism planning typically lack a language for dealing with the destination's experiential content. This article argues that tourism planning has as its central challenge the design of effective touristic experiences, and can find conceptual sources for this task in iconography, the field that studies the meanings of images. In search of iconographie principles for tourism design, the article investigates Niagara Falls, still one of the foremost attractions in North America. At Niagara Falls, the article identifies two main compositional elements: staging, which situates a desirable motif (in this case a waterfall) in a stage setting; and thematizing, which links the motif to concepts (like terror or romance) that make it evocative.
Hybrid genetic approach for the dynamic weapon-target allocation problem

This paper addresses the problem of threat engagement and dynamic weapon-target allocation (WTA) across the force or network-centric force optimization. The objective is to allocate and schedule defensive weapon resources over a given period of time so as to minimize surviving target value subject to resource availability and temporal constraints. The dynamic WTA problem is a NP-complete problem and belongs to a class of multiple-resource-constrained optimal scheduling problems. Inherent complexities in the problem of determining the optimal solution include limited weapon resources, time windows under which threats must be engaged, load-balancing across weapon systems, and complex interdependencies of various assignments and resources. We present a new hybrid genetic algorithm (GA) which is a combination of a traditional genetic algorithm and a simulated annealing-type algorithm for solving the dynamic WTA problem. The hybrid GA approach proposed here uses a simulated annealing-type heuristics to compute the fitness of a GA-selected population. This step also optimizes the temporal dimension (scheduling) under resource and temporal constraints. The proposed method provides schedules that are near-optimal in short cycle times and have minimal perturbation from one cycle to the next. We compare the performance of the proposed approach with a baseline WTA algorithm.
faceting induced by an ultrathin metal film: Pt on W(111)

Abstract The interaction of ultrathin films on Pt with a W(111) surface has been studied using low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and scanning tunneling microscopy (STM). When W(111) is covered with $ 1.1 × 1015 Pt atoms cm 2 and heated in the range 800–1600 K, the surface undergoes a massive restructuring to form microscopic facets. At 1200 K., the average facet dimensions are ≳ 100 A, and the dominant facet orientation is W(211). The faceting appears to be driven by a Pt-enhanced anisotropy in the surface free energy.
Uniform sensing protocol for autonomous rechargeable sensor networks

Autonomous rechargeable sensor networks are becoming a feasible solution to many real world applications. In this paper, we propose a Uniform Sensing Protocol for autonomous rechargeable sensor networks. Our protocol aims to provide uniformly distributed sensing throughout the entire life-time of the network, thus increasing the overall network reliability. It considers the amount of available energy in the environment as well as the probability of encountering a specific number of threats. Using these parameters, each node estimates its own active period, such that uniform sensing is established. We compare the performance of our protocol with static and dynamic active time slot approaches. The simulation results show that the Uniform Sensing Protocol generates fewer failures and has a significantly longer mean time to failure than the other two schemes.
Outcome of periprosthetic distal femoral fractures following knee arthroplasty

Abstract Introduction The majority of periprosthetic fractures around the knee occur at the supracondylar region of the distal femur. Fixation of distal femoral fractures in osteoporotic bone with short segment remains a challenge, especially after total knee arthroplasty (TKA). Internal fixation of these fractures using locking plates has become popular. The purpose of this study was to evaluate a consecutive series of periprosthetic supracondylar femoral fractures treated with locked periarticular plate fixation with regard to surgical procedure, complications and clinical outcome. Materials and methods From two academic trauma centres, 55 consecutive periprosthetic distal femoral fractures (Arbeitsgemeinschaft fur Osteosynthesefragen/Orthopaedic Trauma Association, AO/OTA 33) were retrospectively identified as having been treated with locked plate fixation. Of these, 36 fractures in 35 patients (86.1% female) met the inclusion criteria. Patients had an average age of 73.2 years (range 54–95 years). Fixation constructs for plate length and working length were delineated. Nonunion, infection and implant failure were used as complication variables. Demographics were assessed. Outcome was addressed radiographically and clinically according to Kristensen et al. 1 by range of motion and pain. Results Twenty-five of 36 fractures (69.4%) healed after the index procedure. Eight of 36 fractures (22.2%) developed a nonunion with three fractures (8.3%) leading to hardware failure. Nine of the 36 patients (25%) were radiographically diagnosed with notching of the anterior femoral cortex. Regarding technical aspects, distance from the anterior flange of the femoral component to fracture was significantly shorter in patients with compared to without anterior notching ( t = 3.68, p = 0.02). Patients who underwent submuscular plate insertion compared to an extensive lateral approach had a reduced nonunion risk ( χ 2 = 0.05). No difference in infection rate was found for submuscular procedures compared with open procedures ( χ 2 = 0.85). Range of motion was reduced in most of the patients and 13.5% had a persistent loss of extension of 5°. More than 77% of the patients reported no or only mild pain during the last office visit. Range of motion loss did not influence pain. Successful treatment according to Cain et al. 2 was achieved in 83%. Using Kristensen's 1 criteria, 56% of the knees had acceptable flexion. Conclusion Operative fixation of periprosthetic distal femoral fractures after TKA continues to be challenging. Notching of the anterior femoral cortex should be avoided. Loss of reduction and high failure rates still occur with locked plating and may be related to underlying factors. Indirect reduction and submuscular plate insertion technique reduce nonunion risk.
Magnetic resonance arthrography of the shoulder: accuracy of gadolinium versus saline for rotator cuff and labral pathology

The purpose of this study was to evaluate the necessity of intra-articular gadolinium versus saline alone in magnetic resonance arthrography (MRA) of the shoulder. Our database was reviewed for 100 consecutive shoulder MRA examinations performed between January 2007 and December 2007. Patient information was blinded and images were retrospectively reviewed by at least two radiologists with dedicated musculoskeletal training. T2-weighted (T2W) images were initially analyzed in isolation to simulate MRA with saline alone. After a delay, the full study was analyzed including T1-weighted (T1W) and T2W images. If there was a significant discordance between the two analyses with regard to rotator cuff or labral pathology, the study was again reviewed by all evaluators in consensus to determine if the T1W images offered additional diagnostic information and increased diagnostic confidence. Of the 100 MRA examinations, there were 15 discordant cases. Two cases were discordant with regard to rotator cuff pathology and 13 were discordant on the basis of labral pathology. When the discordant cases were reviewed in consensus, the T2W images appeared to display rotator cuff and labral pathology as definitively as the T1W images. Interobserver and intraobserver variability was favored to have played a role in causing the discordances. MRA of the shoulder performed with joint distention provided by saline alone appears to offer equivalent diagnostic information to MRA performed with gadolinium enhancement. This protocol modification improves efficiency by eliminating several image series and provides a small cost savings by eliminating gadolinium.
COST-PERFORMANCE ANALYSIS OF SERVICE-ADDRESS-ROUTED LEAST-COMMON-ANCESTOR NETWORKS

A novel Interconnection Network Architecture is proposed for integrating tightly coupled Distributed Systems. It allows the implementation of Service Address Routing(SAR): network communications between components are based on the "name" of requested services. It is a client-server communications model, and optionally includes the traditional physical addressing schemes. This enhanced network architecture registers the capabilities of the components attached to its ports and directs service requests to appropriate server nodes. The Network can perform Resource Allocation by placing services in nodes that can support them. Load Distribution is achieved by binding requests to adequate servers with enough free resources. Furthermore, SAR effects a simple, yet efficient and transparent resource discovery mechanism by means of a distributed content-addressable search at each network port. A scalable implementation for computer clusters is proposed which uses the Least-Common-Ancestor Networks (LCANs) as the model for the hierarchical interconnect. At the end of this work, an analysis based on theoretical examination and experimental testing is carried out; scalability and cost-effectiveness of the proposed Service-Address-Routed Least-Common-Ancestor Networks are thus examined.
Acute hemoperitoneum in children: prevalence of low-attenuation fluid.

Background. Recent evidence indicates that acute hemoperitoneum may have lower than expected attenuation values at CT. Objective. To characterize the attenuation of acute hemoperitoneum at CT in children following blunt abdominal trauma and to assess the prevalence of low-attenuation fluid. Materials and methods. The CT scans of 19 consecutive children with isolated hepatic or splenic injury and associated peritoneal fluid were retrospectively analyzed. The attenuation value of peritoneal fluid was assessed in all peritoneal spaces. Results. Fluid was noted in 53 peritoneal spaces (27 abdominal, 26 pelvic). Fluid attenuation ranged from 20 to 64 HU. The mean fluid attenuation in pelvic spaces (37.5 ± 9.4 HU) was significantly lower than in abdominal spaces (444.9 ± 10.2 HU) (P = 0.008). Fluid in 8/26 (31 %) pelvic spaces and 2/27 (7%) abdominal spaces had attenuation values ≤ 30 HU. Fluid surrounding the site of injury (perihepatic or perisplenic space) was significantly higher in attenuation than fluid at other sites (P < 0.001). There was no correlation between the mean attenuation value of peritoneal fluid in each patient and the admission hematocrit (r = -0.14, P = 0.55). Conclusions. There is great variability in the attenuation of acute hemoperitoneum. Blood in pelvic spaces has significantly lower attenuation than blood in abdominal spaces. Hemoperitoneum in the pelvis has values of ≤ 30 HU in approximately one-third of spaces. The attenuation of acute hemoperitoneum does not correlate with hematocrit.
Predation versus resource limitation in survival of adult burrowing wolf spiders (Araneae: Lycosidae).

The influences of food supply and density on adult survival were examined in the burrowing wolf spider Geolycosa rafaelana (Lycosidae), using manipulations of spider populations on eight 400 sq m experimental plots. A total of 110 adult spiders were captured, weighed, marked, and returned to their burrows during April–May 1983. Treatments of (1) food supplementation, (2) density reduction, (3) food supplementation combined with density reduction, and (4) no manipulation (control) were applied to the eight populations, and adult survival and reproduction were monitored during May–October 1983. Survival rates were higher for nonreproducing adult female populations with reduced density, and lower for nonreproducing females in populations with food supplementation. A pompilid wasp, Paracyphononyx funereus, was documented as a parasitoid of G. rafaelana, producing 50%–65% mortality in adult females during winter, and 4–5% mortality in adult females during summer. The observed survival responses were correlated with variations in predation, while parasitism did not appear to be strongly density-dependent.
Alcaligenes xylosoxidans osteomyelitis without trauma in a patient with Good's syndrome.

Since Robert Good's first description of thymoma with hypogammaglobulinemia in 1954 (since called Good's syndrome), fewer than 100 cases have been reported. The last comprehensive review by Tarr et al. listed the organisms that produce morbidity in this entity [1]. We recently encountered a patient who expands the spectrum of complications of this condition. A 61-year-oldmanwith recurrent thymoma developed total agenesis of immunoglobulins (undetectable IgG, IgA, and IgM) and recurrent sinopulmonary infections. Initially, these were controlled by monthly infusions of intravenous immunoglobulin. The patient developed sepsis from an indwelling intravenous catheter. Blood cultures grew Alcaligenes xylosoxidans and he was treated with appropriate antibiotics. Several weeks later, he developed an extremely sensitive ankle; X-rays eventually revealed osteomyelitis of the distal fibula and blood cultures again grew A. xylosoxidans. The patient eventually recovered with protracted treatment. He later died of overwhelming sepsis from a different organism, despite continued immunoglobulin replacement. Terminally, his course was complicated by the development of T-lymphocytosis (30,000) and severe neutropenia. Infection with A. xylosoxidans is uncommon and osteomyelitis is rare. This is the first reported case of infection with this organism in Good's syndrome and the first reported case of A. xylosoxidans osteomyelitis without trauma to bone. As such, it expands the spectrum of complications seen with this syndrome and this organism and complements the earlier report in this journal of an elderly man with Good's syndrome and recurrent respiratory infections [2]. As noted by those authors, thymoma should be in the differential diagnosis of unexplained hypogammaglobulinemia.
The evolution of energetics in eutherian “insectivorans”: an alternate approach

An analysis of standard energetics in 57 species of “insectivorans”, small eutherians that preferentially feed on soil invertebrates, indicated that a combination of climate, the use of torpor, substrate, food habits, and log10 body mass accounted for 92.5% of the variation in log10 basal rate of metabolism in insectivorans, whereas log10 body mass alone accounted for 76.7% of the variation. With the addition of subfamily affiliation, this analysis accounted for 95.5% of the variation in log10 basal rate, the most distinctive subfamilies being Soricinae and the Talpinae, which have equally high basal rates.Sorex species have basal rates that average 2.5 times those of tropical crocidurines, reflecting an approach bySorex to life in cold climates that does not include the use of torpor, a stratagem widely used by crocidurines in warm-temperate and tropical climates. The absence of torpor inSorex may facilitate a high reproductive rate through a high basal rate of metabolism, a combination that may be incompatible with a small mass, insectivorous food habits, and life in the lowland tropics, but required in cold-temperate environments. Insectivorans other than shrews, moles, and cold-temperature hedgehogs have low basal rates principally in association with tropical distributions and the use of torpor. Basal rate of metabolism in insectivorans also correlated with ordinal, familial, subfamilial, and tribal affiliations. The suggestion that phylogeny is an important determinant of performance characters like rate of metabolism ignores the requirement that performance must be compatible with conditions in the environment and with a species’ other characteristics. The principal reason why performance characters are correlated with taxonomic affiliation is that many clades consist of species that share a common approach to the environment. Thus, clades not only represent evolutionary histories, they also are crude measures of physiological and behavioral performances.
Direct genetic selection of a maize cDNA for dihydrodipicolinate synthase in an Escherichia coli dapA- auxotroph.

Dihydrodipicolinate synthase (DHPS; EC 4.2.1.52) is the first committed enzyme in the lysine branch of the aspartate-derived amino acid biosynthesis pathway and is common to bacteria and plants. Due to feedback inhibition by lysine, DHPS serves in a regulatory role for this pathway in plant metabolism. To elucidate the molecular genetic characteristics of DHPS, we isolated a putative full-length cDNA clone for maize DHPS by direct genetic selection in an Escherichia coli dapA−auxotroph. The maize DHPS activity expressed in the complemented E. coli auxotroph showed the lysine inhibition characteristics of purified maize DHPS, indicating that the cDNA encoded sequences for both the catalytic function and regulatory properties of the enzyme. The N-terminal amino acid sequence of purified maize DHPS was determined by direct sequencing and showed homology to a sequence within the cDNA, indicating that the clone contained the entire coding region for a mature polypeptide of 326 amino acids plus a 54 amino acid transit peptide sequence. The molecular weight of 35854, predicted from the deduced amino acid sequence, was similar to the 38 000 Mr determined by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) for the purified enzyme from maize. DHPS mRNAs complementary to the cDNA were detected in RNA isolated from developing maize endosperm and embryo tissues. Southern blots indicated the presence of more than one genomic sequence homologous to DHPS per haploid maize genome.
New Structural Arrangements in Three Ca Uranyl Carbonate Compounds with Multiple Anionic Species

Abstract Three new Ca uranyl carbonates containing nitrate or chlorine have been synthesized by room temperature evaporation of solutions. The structures of each were determined and refined on the basis of F2 for all unique data collected using an APEX CCD-based detector and MoKα radiation. The structures of each contain uranyl tricarbonate clusters of composition [UO2(CO3)3]4− that involve a uranyl hexagonal bipyramid that shares three equatorial edges with CO3 groups. The structure of Ca5[(UO2)(CO3)3]2(NO3)2(H2O)10 (UND-1) consists of a sheet of uranyl tricarbonate clusters that share edges and vertices with Caφn polyhedra (Ca:U=5:2 in the sheet). An (NO3)− group is attached to the sheet by sharing an edge with a Caφn polyhedron. Adjacent sheets are linked by H bonding only. The structure of Ca6[(UO2)(CO3)3]2Cl4(H2O)19 (UND-2) has a sheet of uranyl tricarbonate clusters and Caφn polyhedra that is similar to that found in UND-1, but adjacent sheets are linked by bonds to Ca cations and Cl anions located between the sheets. The structure of Ca12[(UO2)(CO3)3]4Cl8(H2O)47 (UND-3) involves uranyl tricarbonate clusters that share vertices and edges with clusters containing six-member rings of Caφ8 polyhedra, resulting in a heteropolyhedral framework, with Cl anions and H2O groups located in channels through the framework. Crystallographic data: UND-1, R1=0.0467, wR2=0.1022, monoclinic, space group P21/n, a=6.5729(9), b=16.517(2), c=15.195(2) A, β=90.494(3)°, Z=2; UND-2, R1=0.0362, wR2=0.1115, tetragonal, space group P4/mbm, a=16.744(2), c=8.136(1) A, Z=2; UND-3, R1=0.0367, wR2=0.1110, cubic, space group Fd 3 , a=27.489(3) A, Z=8.
Caenorhabditis elegans anillin (ani-1) regulates neuroblast cytokinesis and epidermal morphogenesis during embryonic development.

Abstract The formation of tissues is essential for metazoan development. During Caenorhabditis elegans embryogenesis, ventral epidermal cells migrate to encase the ventral surface of the embryo in a layer of epidermis by a process known as ventral enclosure. This process is regulated by guidance cues secreted by the underlying neuroblasts. However, since the cues and their receptors are differentially expressed in multiple cell types, the role of the neuroblasts in ventral enclosure is not fully understood. Furthermore, although F-actin is required for epidermal cell migration, it is not known if nonmuscle myosin is also required. Anillin (ANI-1) is an actin and myosin-binding protein that coordinates actin–myosin contractility in the early embryo. Here, we show that ANI-1 localizes to the cleavage furrows of dividing neuroblasts during mid-embryogenesis and is required for their division. Embryos depleted of ani-1 display a range of ventral enclosure phenotypes, where ventral epidermal cells migrate with similar speeds to control embryos, but contralateral neighbors often fail to meet and are misaligned. The ventral enclosure phenotypes in ani-1 RNAi embryos suggest that the position or shape of neuroblasts is important for directing ventral epidermal cell migration, although does not rule out an autonomous requirement for ani-1 in the epidermal cells. Furthermore, we show that rho-1 and other regulators of nonmuscle myosin activity are required for ventral epidermal cell migration. Interestingly, altering nonmuscle myosin contractility alleviates or strengthens ani-1's ventral enclosure phenotypes. Our findings suggest that ventral enclosure is a complex process that likely relies on inputs from multiple tissues.
Commentary on present practice

Specimen size and mechanical factors in plane strain fracture toughness testing of metallic materials
Accessibility of Cholesterol in Endoplasmic Reticulum Membranes and Activation of SREBP-2 Switch Abruptly at a Common Cholesterol Threshold

Recent studies have shown that cooperative interactions in endoplasmic reticulum (ER) membranes between Scap, cholesterol, and Insig result in switch-like control over activation of SREBP-2 transcription factors. This allows cells to rapidly adjust rates of cholesterol synthesis and uptake in response to even slight deviations from physiological set-point levels, thereby ensuring cholesterol homeostasis. In the present study we directly probe for the accessibility of cholesterol in purified ER membranes. Using a soluble cholesterol-binding bacterial toxin, perfringolysin O, we show that cholesterol accessibility increases abruptly at ∼5 mol % ER cholesterol, the same concentration at which SREBP-2 activation is halted. This switch-like change in cholesterol accessibility is observed not only in purified ER membranes but also in liposomes made from ER lipid extracts. The accessibility of cholesterol in membranes is related to its chemical activity. Complex formation between cholesterol and some ER phospholipids can result in sharp changes in cholesterol chemical activity and its accessibility to perfringolysin O or membrane sensors like Scap. The control of the availability of the cholesterol ligand to participate in cooperative Scap/cholesterol/Insig interactions further sharpens the sensitive switch that exerts precise control over cholesterol levels in cell membranes.
A programmable, microprocessor-controlled temperature stage for burn and freezing studies in the microcirculation

Abstract A programmable, microprocessor-based thermal control system is interfaced with a specially fabricated variable-temperature light microscope stage to deliver precise burns and freezes to mesentary microcirculatory preparations. The stage is designed around a hollow, transparent pedestal through which both heating and cooling fluxes can be transmitted directly to a tissue which is to be observed. Cooling is produced by a flow of cryogenically refrigerated gas through the stage, whereas heating is effected by the dissipation of electrical energy in a resistive semiconductor film spray deposited onto the surface of a glass plate on which the tissue is placed. Various desired thermal protocols are achieved by continual adjustment between the magnitudes of refrigeration and heating loads imposed simultaneously upon the system. The specimen temperature is monitored at a sampling rate of 512/sec by a microthermocouple mounted in close thermal communication with the tissue, and is used as the input signal to the microprocessor control system. A unique temperature/time profile is selected and assigned to the programmable controller at the time of each individual experiment. In the present configuration the performance limits of this apparatus provide for a tissue temperature range of −48 to 80° with linear thermal transients between 1 and 6000°/min.
Children's speech recognition with application to interactive books and tutors

We present initial work towards development of a children's speech recognition system for use within an interactive reading and comprehension training system. We first describe the Colorado Literacy Tutor project and two corpora collected for children's speech recognition research. Next, baseline speech recognition experiments are performed to illustrate the degree of acoustic mismatch for children in grades K through 5. It is shown that an 11.2% relative reduction in word error rate can be achieved through vocal tract normalization applied to children's speech. Finally, we describe our baseline system for automatic recognition of spontaneously spoken story summaries. It is shown that a word error rate of 42.6% is achieved on the presented children's story summarization task after using unsupervised MAPLR (maximum a posteriori linear regression) adaptation and VTLN (vocal tract length normalization) to compensate for inter-speaker acoustic variability. Based on this result, we point to promising directions for further study.
The impact of instructional elements in computer-based instruction

This study investigated the effects of several elements of instruction (objectives, information, practice, examples and review) when they were combined in a systematic manner. College students enrolled in a computer literacy course used one of six different versions of a computer-based lesson delivered on the web to learn about input, processing, storage and output of a computer. The six versions of the program consisted of (1) a full version that contained information plus objectives, practice with feedback, examples and review, (2) a version without objectives, (3) one without examples, (4) one without practice, (5) one without review and (6) a lean version containing information only. Results indicated participants who used one of the four versions of the computer program that included practice performed significantly better on the posttest and had consistently more positive attitudes than those who did not receive practice. Implications for the development of computer-based instruction are explored.