cssi/SciSciGPT-SciSciNet huggingface dataset:
Models of Length Dependent Behavior in Polyglutamine based on Improved Simulation Methods

We present a study of the length-dependent statistical mechanical behavior of monomeric polyglutamine tracts over a broad range of repeat lengths, using implicit solvent as well as novel replica exchange based explicit solvent molecular dynamics techniques that allow for drastic conformational change in peptides of these sizes. First, these methodological changes were validated by comparison with conventional simulations, then equilibrium thermodynamic models were fit to simulation data, showing a crossover from alpha helical structure to either beta sheet rich or disordered structures with increasing monomer length, depending on the choice of solvent model.
pH-responsive swelling behavior of poly(vinyl alcohol)/poly(acrylic acid) bi-component fibrous hydrogel membranes

The pH-responsive dimensional expansion and mass uptake of bi-component hydrogels in the form of fibrous membranes and films were reported. Fibrous membranes and monolithic films were prepared from aqueous mixture of poly(vinyl alcohol) and poly(acrylic acid) at 3.5 COOH/OH molar composition via electrospinning and solution cast, respectively, then cross-linked by heat-induced esterification. Both forms of hydrogels exhibited increasing swelling with increasing pH. For hydrogel fibrous membranes, planar expansion was immediate without the time lag observed on the films, and equilibrium thickness expansion and mass uptake took far longer than planar expansion. The dimensional expansion in the thickness direction was much higher than that in the planar directions for the fibrous membranes, while they were comparable for monolithic films. The peculiar asymmetric dimensional expansion of fibrous membrane is explicable with the asymmetric distribution of the fibers on the planar and thickness directions, which is formed during layer-by-layer collection process of electrospinning. The fibrous membranes distinguished themselves as being far stronger and faster in re-absorption in the swollen state than the cast-films.
Renormalization group calculation for critical points of higher order with general propagator

Abstract We give first order perturbation results for the critical point exponents at order O critical points with anisotropic propagators. The exponent η is calculated to second order for isotropic propagators, and all O ; 1/ n expansion results are given for O = 2.
Comparative structural and functional features of the human fibrinogen alpha C domain and the isolated alpha C fragment. Characterization using monoclonal antibodies to defined COOH-terminal A alpha chain regions.

The alpha C domain of fibrinogen (A alpha-(220-610)) plays a central role in maintaining hemostasis by serving as a substrate for factor XIIIa and plasmin. Monoclonal antibodies that recognize eight distinct epitopes within the COOH-terminal two-thirds of the A alpha chain were employed as structural probes to: 1) isolate the human alpha C domain, 2) compare the topography of the eight epitopes within the alpha C domain of intact fibrinogen and in purified alpha C fragments, and 3) explore the degree to which the alpha C domain's role as a factor XIIIa substrate in intact fibrinogen is preserved within the structure of isolated alpha C fragments. Five antibodies were raised against small, synthetic peptide immunogens (A alpha-(220-230), A alpha-(425-442), A alpha-(487-498), and A alpha-(603-610)), and three were generated against larger cyanogen bromide (A) alpha chain derivatives with each epitope subsequently localized to discrete A alpha chain sequences (A alpha-(259-276), A alpha-(529-539), and A alpha-(563-578)). Human alpha C preparations were isolated from mild plasmin digests of fibrinogen by successive chromatography on concanavalin A-Sepharose, anti-A alpha-(425-442)-Sepharose, and Superdex-75 fast protein liquid chromatography. Immunochemical characterization indicated that the NH2-terminal residue of alpha C fragments was either A alpha-220 or A alpha-231 and that, although the extreme COOH-terminal region, A alpha-(603-610), was absent, all molecules were intact at least through A alpha-(563-578). Solution phase competitive assays indicated that the release of the alpha C domain from intact fibrinogen was associated with several conformational changes, e.g. in the vicinity of A alpha-(220-230), A alpha-(259-276), A alpha-(487-498), and A alpha-(529-539), but that the relative accessibility of other localized structures remained unchanged, e.g. A alpha-(425-442) and A alpha-(563-578). Immunoblotting analysis of alpha C cross-linking in vitro revealed that isolated alpha C fragments could serve as a substrate for factor XIIIa. Immunoblotting studies of the A alpha chain proteolysis that occurs during thrombolytic therapy indicated that alpha C fragments, similar in size and epitope content to those isolated from purified fibrinogen, were released in vivo early during fibrinolytic system activation. The collective findings provide new information about the fine structure of the fibrinogen alpha C domain and its functional implications and also draw attention to the as yet unexplored role of alpha C fragments in the pathophysiology of thrombosis and hemostasis.
Complications in smokers after postmastectomy tissue expander/implant breast reconstruction

Smoking is universally considered to be a risk factor for surgical complications. The incidence of complications following tissue expander/implant breast reconstruction in patients who smoke has not been previously evaluated.A review of complications following tissue expander/implant reconstruction in 515 patients was performed. Patients who had 2-stage, tissue expander/implant reconstruction at Memorial Sloan-Kettering Cancer Center between May 2002 and December 2003 were included. Complications in smokers (n=132) and nonsmokers (n=383) were compared. The rate of overall complications, reconstructive failure, mastectomy flap necrosis, and infectious complications was significantly higher in smokers compared with nonsmokers. The rate of complications in ex-smokers was also higher than in nonsmokers. Using multivariate statistical analysis to adjust for confounding variables, smoking was identified as independent predictor of postoperative complications.A significant association between smoking status and postoperative complications exists. Thus, smokers who undergo postmastectomy expander/implant reconstruction should be informed of the increased risk of surgical complications and should be counseled on smoking cessation.
A time and imaging cost analysis of low-risk ED observation patients: a conservative 64-section computed tomography coronary angiography “triple rule-out” compared to nuclear stress test strategy

Abstract Study Objective The study aimed to examine time and imaging costs of 2 different imaging strategies for low-risk emergency department (ED) observation patients with acute chest pain or symptoms suggestive of acute coronary syndrome. We compared a “triple rule-out” (TRO) 64-section multidetector computed tomography protocol with nuclear stress testing. Methods This was a prospective observational cohort study of consecutive ED patients who were enrolled in our chest pain observation protocol during a 16-month period. Our standard observation protocol included a minimum of 2 sets of cardiac enzymes at least 6 hours apart followed by a nuclear stress test. Once a week, observation patients were offered a TRO (to evaluate for coronary artery disease, thoracic dissection, and pulmonary embolus) multidetector computed tomography with the option of further stress testing for those patients found to have evidence of coronary artery disease. Results We analyzed 832 consecutive observation patients including 214 patients who underwent the TRO protocol. Mean total length of stay was 16.1 hours for TRO patients, 16.3 hours for TRO plus other imaging test, 22.6 hours for nuclear stress testing, 23.3 hours for nuclear stress testing plus other imaging tests, and 23.7 hours for nuclear stress testing plus TRO (P Conclusion Triple rule-out reduced total length of stay and imaging time but incurred higher imaging costs. A per-hospital analysis would be needed to determine if patient time savings justify the higher imaging costs.
The Synthesis and Metabolism of Radioactively-Labeled Steroids

Publisher Summary This chapter focuses on synthesis and metabolism of radioactively labeled steroids. The most profound changes in the animal body, including the development of the secondary sex characters and the genesis of certain sorts of cancer, are mediated by steroids. The use of radioactively labeled steroids in attempts to study effects of hormones on body is eminently practical for three reasons: The labeled steroid appears to be chemically identical with the natural one and behaves in the same way; it can be followed in the course of its metabolism without the necessity of complete isolation and identification at every step; and the sensitivity of the methods of detection are such that the minute quantities within the range of normal physiological doses are still detectable and their fractions isolatable. This chapter summarizes the synthetic methods that have been used, giving their yields and practicability. It describes the results that have been obtained by the injection of labeled steroids in tracing their possible sites of localization in the tissues and their routes and mechanisms of excretion.
Regulatory Framework for the Availability and Use of Animal Drugs in the United States

The goal of this article is to help practitioners understand the regulatory framework and basis for the approval of new animal drugs, the terminology and specific meaning of terms related to drug approval, and the marketing and use of veterinary drugs in companion animal practice. Understanding the differences between approved versus unapproved drugs and their use helps practitioners make the appropriate clinical decisions on their patients’ treatment. Only when buying approved animal drugs can clinicians be assured of product safety, effectiveness, and manufacturing to the strict standards for quality, purity, and potency, as well as truthful and complete labeling.
EXPERIMENTAL EVIDENCE FOR THE INFLUENCE OF ATOMIC BINDING ON THE DECAY RATE OF NEGATIVE MUONS

In order to make precise determinations of the rate of nuclear capture of muons for the disappearance of muons, the ratio R = LAMBDA /sub dec/(Z)/ LAMBDA /sub dec/(O) was measured directiy for a variety of elements. Some preliminary results are given. (W.D.M.)
A method for analyzing vibration power absorption density in human fingertip

In the current study, we hypothesize that the vibration power absorption density (VPAD) is a good measure for the vibration exposure intensity of the soft tissues of the fingers. In order to calculate the VPAD at a fingertip, we proposed a hybrid modeling approach, which combines a 2D finite element (FE) model with a lumped parameter model. Whereas the lumped components are used to represent the global biodynamic characteristics of the hand-arm system, the FE component is used to predict the detailed stresses, strains, and VPAD in the fingertip. The lumped parameters are determined by using the vibration transmissibilities measured at the fingertip, while the material parameters of the soft and hard tissues of the FE model are adopted from the published experimental data. The proposed model was applied to predict the distributions of dynamic displacement, velocity, and VPAD in the soft tissues of the fingertip. Furthermore, we have derived the frequency weighting based on the VPAD of the soft tissue. The preliminary analysis indicated that the VPAD-based frequency weighting is substantially different from the ISO weighting in that the ISO frequency weighting emphasizes the effect of the vibration at frequencies lower than 25 Hz whereas the VPAD-based weighting generally emphasizes the resonant responses of the finger. Our analysis indicated that the VPAD-based weighting was fairly consistent with the finger surface vibration transmissibility at frequencies greater than the first resonance, suggesting that the finger surface transmissibility may be used as an alternative frequency weighting for assessing the finger vibration exposure. The proposed method provides a practical and efficient tool to simulate the detailed biodynamic responses of a complex biological system to vibration.
Simultaneous measure of x-ray induced X-Y and autosomal crossingover in spermatocytes of Drosophila.

Radiation induced X-Y and autosomal crossingover was followed in primary spermatocytes ofDrosophila males. Males of the compositiony/BSy+ were X-rayed 1–2 hours after the prepupal stage and mated daily with threey;dp cn bw females. The results suggest that the frequency of recovered X-Y crossovers is highest in the late spermatocyte stage about to undergo the first meiotic division, whereas the peak frequency of autosomal crossovers occurs in earlier spermatocytes. The results are explainable if (1) a more appropriate “pairing” configuration exists between X and Y than between autosomes at later stages of the primary spermatocyte, a situation which is reversed in earlier stages; (2) breakability of Y (and/or X) heterochromatin and centromeric heterochromatin of autosomes are different from each other at different stages of the primary spermatocyte; or (3) a combination of both.
Text-based communication influences self-esteem more than face-to-face or cellphone communication

Diary data was collected for 76 participants over 6day intervals.3649 social interactions were randomly sampled across communication channels.Self-esteem was measured at baseline and follow-up.Face-to-face communication was the most frequent form of communication.Text-based communication was most influential on self-esteem. Meaningful social interactions are positively associated with improvements in self-esteem, but this phenomenon has largely been unexplored in digital media despite the prevalence of new, text-based communication (e.g. Facebook, texting, email, etc.). To address this gap in the literature the frequency and quality, or meaningfulness, of communication was measured in mediated and non-mediated channels across a random sample of 3649 social interactions using Experience Sampling Methods. Results revealed that most communication took place face-to-face (62%), with less text-based (about 22%) and cell phone voice (14%) communication. Meaningful face-to-face and text-based communication were associated with changes in self-esteem according to a marginally significant and significant finding, respectively. Text-based communication was more important for self-esteem than face-to-face or phone communication, which is consistent with research on the magnifying effect of text-based communication on interpersonal processes. According to the Internet enhanced self-disclosure hypothesis, the psychological benefits of text-based communication stems from enhanced self-disclosure, which is also supported in the data. Additional work is needed to better understand the mechanisms underlying the positive relationship between meaningful text-based interactions and self-esteem, but findings point to the important role of digital communication for psychological health.
Internally Calibrated Quantification of Protein Analytes in Human Serum by Fluorescence Immunoassays in Disposable Elastomeric Microfluidic Devices

Herein we report on reliable reproducible quantification of protein analytes in human serum by fluorescence sandwich immunoassays in disposable PDMS microfluidic chips. The system requires 1000 times less sample than typical clinical blood tests and is specifically shown to measure ferritin down to 250 pM in human serum. The in-built calibration method of spiking the serum with known concentrations of commercially available antigen avoids common sources of error and improves the reliability of the test results. The reported microfluidic system is an important new tool for fundamental scientific research, offering sensitive immunoassay measurements in small but complex biosamples. The system is also a further step towards comprehensive affordable "point-of-care" biomedical diagnostics.
Response to Meyer, Dominic et al., and Lin and Schembre

To the Editor: Dr Meyer states (1) that the new American College of Gastroenterology Guidelines for Colorectal Cancer Screening 2008 (2) "do not even agree with the previous ACG guidelines." In fact, the earlier American College of Gastroenterology (ACG) guidelines (3), published in 2000, also recommended colonoscopy as the preferred screening test and were the first to do so. The American Society for Gastrointestinal Endoscopy (4) and the National Comprehensive Cancer Network (5) each subsequently endorsed colonoscopy as the preferred screening test. The fact that there are not enough colonoscopists to perform screening colonoscopy is debatable (6), but the guideline states (2) that "it is recognized that colonoscopy is not available in every clinical setting because of economic limitations. It is also recognized that not all eligible individuals are willing to undergo screening colonoscopy for screening purposes." Alternative screening strategies and their rationales are discussed in detail in the guidelines (2). The ACG continues to endorse the US Multi-Society on Colorectal Cancer screening guidelines (7), which present a menu of screening options. However, there is no evidence that offering multiple options increases the number of patients who get screened, and the approach of offering a preferred option may actually result in higher screening rates (8,9). Furthermore, the approach endorsed by the ACG in 2000 is closer to what is actually done in clinical practice (10) in the United States than any of the "menu-of-options" approaches to screening (7,11). These rationales are discussed in detail in the guidelines. With regard to the issue of the guidelines being self-serving, the ACG endorsed the use of computed tomography (CT) colonography in the Multi-Society Task Force guidelines (7) as an alternative to colonoscopy and again in the ACG guidelines as an alternative option in patients unwilling to undergo colonoscopy (2). In contrast, the US Prevantive Services Task Force declined to recommend any function of CT colonography in screening (11). Although the guidelines may be interpreted by some as self-serving, that does not negate the substantial evidence that a high-quality colonoscopy remains the most effective colorectal cancer screening strategy available, or that large-scale colonoscopy screening programs exist now in Germany, Italy, and Poland.
Polyomavirus-associated nephropathy risk in kidney transplants: the influence of recipient age and donor gender

Polyomavirus-associated nephropathy (PVAN) is a frequent cause of kidney transplant failure. We determined the risk factors for biopsy-proven PVAN among 1027 recent kidney transplant recipients by univariate and multivariate analyses. The rate of PVAN was determined over an univariate and multivariate analysis over an average of 30 months of follow-up of patients receiving predominantly living donor grafts with antibody induction and sequential surveillance biopsies to detect subclinical graft disease. Seventy-four transplant recipients were diagnosed with PVAN with the finding made on surveillance biopsy in 40 patients. These 40 cases did not differ from the 34 non-surveillance cases with respect to baseline clinical characteristics or initial histological features. Older recipient age and female donor gender were independent risks associated with PVAN. Factors not linked to PVAN risk included the use and type of induction agent, use of tacrolimus vs sirolimus, the number of human lympocyte antigen (HLA) mismatches, or the frequency of acute rejection. We conclude that PVAN preferentially affects older age patients and allografts from female donors but is unrelated to immunological risk, choice of immunosuppression, or rejection history.
Design of long-distance telecommunication networks -The Telpak problem

The government procures long-distance circuits from communication carriers under a bulk-rate tariff referred to as Telpaks. While physical implementation of circuits is performed by the carriers, the arrangement of circuits into Telpaks for billing purposes is the government's responsibility. Since Telpaks were established in 1961, the government has arranged its circuits into Telpaks on a manual basis. As a result, it has never been able to achieve a minimum cost grouping for over 60 000 circuits among more than 3000 service points. Further, the problem of minimizing the cost of Telpaks has defied classical mathematical approaches because of the large number of service points and circuits. By applying heuristic design techniques, the systematic procedure which is described in this paper has been developed for automating the design of the government Telpak network. Its use has resulted in substantial cost savings over the manually obtained configuration.
Head-up displays - Part 2

In Part 1 the background parameters were traced which specify the requirements for head-up displays. The design of the most common type was used as a vehicle for a broad description of the device. In this second, concluding, part more specific discussion of existing and proposed optical solutions to the airborne head-up display problem are given.
The effect of divalent ions on the isolation of proteins from rat liver nucleoprotein

Abstract The nature and quantity of acid-soluble proteins separated from rat liver nucleoprotein is greatly dependent upon the presence of divalent metal ions. In the absence of these ions, and particularly in the presence of EDTA, low yields of protein are obtained because of greater solubility of the nuclear contents. Moreover, the use of EDTA selectively removes the “arginine-rich” proteins from the nucleoprotein pellet, so that eventual protein fractionation results in relatively extensive retention of “arginine-poor” proteins. The use of divalent metal ions (Mg 2+ , Mn 2+ ) produces similar fractionation patterns. The use of NaCl as the electrolyte allows the isolation of some arginine-rich protein, but in very low yield when compared to the preparations using divalent ions. Thus, ionic strength is a minor factor in the extraction of the arginine-rich proteins from such nuclei, but the presence of divalent metal ions is the most important requirement. Evidently these metal ions exercise an important role in maintaining the structural integrity of arginine-rich nucleoproteins in the nuclei.
Length dependence of the resistance in thin copper wires

The resistance of thin copper wires, area 4 × 10−12 cm2 to 1 × 10−10 cm2, has been measured at low temperatures. For wires with lengths greater than about 5 μm, the resistance begins to increase as the temperature decreases below about 6 K as predicted by the theory of Anderson localization and electron-electron interactions. For wires with lengths less than 5 μm, the temperature dependence of the resistance deviates from the behavior observed for long wires and this deviation increases as the length of the wire decreases. A thermal cutoff length of < 1.0 μm is found which is consistent with both the temperature dependence and the length dependence. A characteristic length of < 1.4 μm is found for localization theory.
Spatial bioaccumulation modeling in a network of bayous

Abstract A software system, Spatial Network Bioaccumulation Model (SNBM), was developed to model the bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in aquatic food webs. The SNBM uses a geographic information system as an engine to: (i) store the spatial representation of input parameters (the data related to the ecosystem), (ii) transfer input and output data to and from the food-web bioaccumulation model, and (iii) display the predicted food-web organism concentrations over a base map of the field site. The bioaccumulation model is a time-dependent, set of first-order ordinary differential equations that are solved numerically. Many sampling locations can be analyzed using the SNBM in one individual run. We demonstrate the system for a steady-state simulation of three PAHs, naphthalene, phenanthrene and benzanthracene in a food web for spotted gar (Lepisosteus oculatus) from the LaBranche Wetlands, Louisiana, USA. The predicted food-web organism concentrations are plotted at their respective sampling location.
A new detection technique for identifying chipless RFID tags

A chipless RFID system includes a reader, antenna and multiple tags presented in the main beam of the reader antenna. In addition, there are some background objects in the reader zone which makes the identifying process more challenging. Each tag has a unique ID, which is incorporated as a set of natural resonant frequencies. The presence or absence of these assigned resonances are considered as bit 1 and 0, respectively. In some practical applications, multiple tags may exist in the reader zone. In such cases, the detection and identification of the tags is challenging. Here, we introduce a new space-time-frequency identification technique by which we can distinguish the poles (complex natural resonances) of the tags successfully.
An Evolutionary Path to Deeply Understanding the Joys of Normal Birth

No matter how much one hears or reads about the desirability of normal birth, it can be difficult to comprehend the feasibility or magnificence of normal birth in a society where it is only rarely seen or experienced. In this column, a nurse describes how a series of “Ah-ha!” experiences shaped her understanding of and appreciation for normal birth.
Resolution of Optical Isomers as the Mixed Chelate Copper(III) Complexes by Reversed Phase Chromatography

Abstract Highly selective separation of D and L amino acids can be effected by reversed phase chromatography of mixed chelate complexes of the analyte acids with equimolar concentrations of Cu(II) and an optically active second amino acid in the mobile phase. The stabilities of the formed diastereomeric ternary complexes will determine the resolution of enantiomers. By this approach, amino acids were resolved as the dansyl and O-phthalaldehyde (OPA) derivatives and imino acids were separated without derivatization. Resolution of D and L dansyl amino acids was accomplished as the mixed complexes of Cu(II) with L-proline, L-arginine, L-histidine and L-histidine methyl ester as the second amino acids. Among the chiral ligands we studied, L-histidine methyl ester is unique in that it possesses both achiral selectivity for the dansyl amino acids and chiral selectivity for the respective D and L enantiomers. With a mobile phase gradient of acetonitrile in a buffer containing Cu(II) L-histidine methyl ester comp...
Scale anomaly and the scalars

We investigate the properties of a possible low-lying scalar glueball as well as the ordinary scalar-quark states using an effective chiral Lagrangian which satisfies the trace anomaly and U(1${)}_{\mathrm{A}}$ anomaly of QCD. An interesting mass bound for the lightest particle in the scalar-singlet channel is discussed. Detailed arguments against the existence of a very light (less than 400 MeV) scalar glueball are presented. It is shown that the introduction of a derivative-coupling term in the usual type of linear \ensuremath{\sigma} model cures the problem of excessively large widths for the ordinary (nonet) scalar mesons. In fact, chiral symmetry enables one to nicely correlate the widths of the entire scalar nonet. It is noted that the same derivative-coupling term allows a heavy (1--2 GeV) scalar glueball to have sufficiently narrow width to permit its observation as an ordinary resonance, in contrast with a recent claim. Our model can naturally explain the unusually large partial width for the \ensuremath{\eta}\ensuremath{\eta}' mode of the glueball candidate G(1590). A symmetrical ansatz for the anomaly terms is suggested which enables one to successfully calculate the \ensuremath{\eta}' mass as the ratio of gluon condensate to pion-decay constant. In addition, the theoretically interesting limit where the glueball becomes a true dilaton is formulated in a new and illustrative way.
Net Zero Fort Carson: Integrating Energy, Water, and Waste Strategies to Lower the Environmental Impact of a Military Base

Military bases resemble small cities and face similar sustainability challenges. As pilot studies in the U.S. Army Net Zero program, 17 locations are moving to 100% renewable energy, zero depletion of water resources, and/or zero waste to landfill by 2020. Some bases target net zero in a single area, such as water, whereas two bases, including Fort Carson, Colorado, target net zero in all three areas. We investigated sustainability strategies that appear when multiple areas (energy, water, and waste) are integrated. A system dynamics model is used to simulate urban metabolism through Fort Carson's energy, water, and waste systems. Integrated scenarios reduce environmental impact up to 46% from the 2010 baseline, whereas single-dimension scenarios (energy-only, water-only, and waste-only) reduce impact, at most, 20%. Energy conserving technologies offer mutual gains, reducing annual energy use 18% and water use 15%. Renewable energy sources present trade-offs: Concentrating solar power could supply 11% of energy demand, but increase water demand 2%. Waste to energy could supply 40% of energy demand and reduce waste to landfill >80%, but increase water demand between 1% and 22% depending on cooling system and waste tonnage. Outcomes depend on how the Fort Carson system is defined, because some components represent multiple net zero areas (food represents waste and energy), and some actions require embodied resources (energy generation potentially requires water and off-base feedstock). We suggest that integrating multiple net zero goals can lead to lower environmental impact for military bases. [ABSTRACT FROM AUTHOR]
Review of Why are Women More Religious than Men

Why are Women More Religious than Men? by Marta Trzebiatowska and Steve Bruce, Oxford University Press
Nitrogen regulation in bacteria and archaea.

A wide range of Bacteria and Archaea sense cellular 2-oxoglutarate (2OG) as an indicator of nitrogen limitation. 2OG sensor proteins are varied, but most of those studied belong to the PII superfamily. Within the PII superfamily, GlnB and GlnK represent a widespread family of homotrimeric proteins (GlnB-K) that bind and respond to 2OG and ATP. In some bacterial phyla, GlnB-K proteins are covalently modified, depending on enzymes that sense cellular glutamine as an indicator of nitrogen sufficiency. GlnB-K proteins are central clearing houses of nitrogen information and bind and modulate a variety of nitrogen assimilation regulators and enzymes. NifI1 and NifI2 comprise a second widespread family of PII proteins (NifI) that are heteromultimeric, respond to 2OG and ATP, and bind and regulate dinitrogenase in Euryarchaeota and many Bacteria.
Energy-aware adaptive OFDM systems

An effective way of reducing the energy consumption without affecting the quality of service is by adapting to the channel conditions. In this paper we describe one such scheme for an OFDM system using space division multiplexing technology. We consider tuning parameters such as modulation level and number of antennas that are considered by WiMax and LTE, as well as number of sub-carriers, peak to average power ratio, interpolation, pilot length and cyclic prefix. We describe a two-phase procedure for determining the parameter settings for minimizing energy consumption given the transmission rate, error performance and channel conditions for frequency selective fading channels. Our results show that we can reduce energy by an additional 5%–30% compared to systems that can only adapt modulation order and number of antennas.
Brain structure localization in positron emission tomography: comparison of magnetic resonance imaging and a stereotactic method.

Abstract A method commonly used for localization of brain regions on positron emission tomographic (PET) images is direct visualization and designation of structure on the image itself. This technique, however, is limited to portions of the brain having sufficient differential radionuclide uptake to permit the recognition of structure by observers familiar with brain anatomy. Two other methods commonly used instead of direct visualization are magnetic resonance imaging (MRI) and stereotactic methods of localization. This report compares the accuracy of a MRI method versus a stereotactic method of brain structure localization on PET. The three localization methods were analyzed for sixteen different brain regions in 5 different subjects by two independent observers. The results were converted to PET pixel size (1 pixel=.127 cm) for comparison. MRI localization differed from direct visualization by a mean and standard deviation of ∼2±1 pixels in both the X and Y dimensions. Stereotactic localization differed from direct visualization by ∼2±1 pixels in the X dimension and by ∼6±2 pixels in the Y dimension. This larger variation seen with the stereotactic method may be, attributed to the questionable assumption of linearity of structure location with respect to size of the inner table of the calvarium.
Stabilization of Lactose Metabolism in Streptococcus lactis C2

The integration of the lactose plasmid from lactic streptococci into the host chromosome could stabilize this trait for dairy fermentations. Sixty lactose-positive (Lac) transductants of lactose- and proteinase-negative (Lac Prt) LM0220 were induced for temperature phage by UV irradiation or mitomycin C. Four of the transductants, designated KB18, KB21, KB54, and KB58, yielded lysates demonstrating less than one Lac transductant per 0.2 ml of phage lysate. Successive transferring in the presence of acriflavine did not yield Lac segregants from KB18, KB21, KB54, or KB58, whereas Streptococcus lactis C2 (parent culture) and three other Lac transductants showed 12 to 88% conversion from Lac to Lac within 6 to 10 repetitive transfers. When grown in continuous culture, KB21 did not show any Lac variants in 168 h, while S. lactis C2 had 96% conversion from Lac to Lac in 144 h. Agarose gel electrophoresis of plasmid DNA isolated from KB18, KB21, KB54, and KB58 revealed that the lactose plasmid, pLM2103, normally present in Lac transductants, was missing. This suggested integration of the transferred lactose plasmid into the chromosome. In contrast to phage lysates induced from S. lactis C2, which exhibited an exponential decrease in the number of Lac transductants after exposure to small doses of UV irradiation, the transduction frequency for lactose metabolism was stimulated by UV irradiation of lysates from KB58. The latter indicated chromosomal linkage for lac and that integration of the lactose genes plasmid into the chromosome had occurred.
Macrophages and vascular adhesion molecules in oral Kaposi's sarcoma

Kaposi's sarcoma (KS) is a heterogeneous tumor where spindle cells are predominant and macrophages and factor XIIIa positive dendrocytes are abundant. The origin of the macrophages and dendrocytes is unclear, although their numbers suggest a critical role in KS pathogenesis. To determine if KS macrophages are recruited from the blood stream or proliferate on-site, we examined biopsy specimens 1) for expression and distribution of vascular adhesion molecules (PECAM-1, ELAM-1, ICAM-1, VCAM-1, P-selectin, L-selectin) and the macrophage-associated adhesion-molecule ligand, VLA-4; 2) for dual expression of proliferation (Ki-67) and lineage-associated markers (KP-1, CD34, factor XIIIa, LCA); and 3) for dual expression of macrophage (KP-1) and endothelial cell (CD34) associated markers. Avidinbiotin peroxidase techniques were used. Resident vessels were found to strongly express PECAM-1, ELAM-1, ICAM-1, P-selectin, and moderately express VCAM-1 and VLA-4. Tumor spindle cells showed less intense expression of ELAM-1, ICAM-1 and P-selectin. The most frequent double-stain combination was Ki-67 + CD34+. In contrast, the combinations of Ki-67 + KP-1+, Ki-67 + XIIIa+ and Ki-67 + LCA+ were rarely seen. The enhanced expression of adhesion molecules on resident vessels and the lack of evidence of macrophage proliferation suggest that the abundant macrophages in KS are recruited from the blood stream.
The effects of aging on the responses of primary human osteoblasts to implant materials

Primary human osteoblasts cultured on implant materials demonstrated differences in cell attachment, percent collagen synthesized and mineralization depending on the age of the patient.
Nonperturbative QCD Simulations with 2+1 Flavors of Improved Staggered Quarks

Dramatic progress has been made over the last decade in the numerical study of quantum chromodynamics (QCD) through the use of improved formulations of QCD on the lattice (improved actions), the development of new algorithms, and the rapid increase in computing power available to lattice gauge theorists. In this article simulations of full QCD are described using the improved staggered quark formalism, ''asqtad'' fermions. These simulations were carried out with two degenerate flavors of light quarks (up and down) and with one heavier flavor, the strange quark. Several light quark masses, down to about three times the physical light quark mass, and six lattice spacings have been used. These enable controlled continuum and chiral extrapolations of many low energy QCD observables. The improved staggered formalism is reviewed, emphasizing both advantages and drawbacks. In particular, the procedure for removing unwanted staggered species in the continuum limit is reviewed. Then the asqtad lattice ensembles created by the MILC Collaboration are described. All MILC lattice ensembles are publicly available, and they have been used extensively by a number of lattice gauge theory groups. The physics results obtained with them are reviewed, and the impact of these results on phenomenology is discussed. Topics includemore » the heavy quark potential, spectrum of light hadrons, quark masses, decay constants of light and heavy-light pseudoscalar mesons, semileptonic form factors, nucleon structure, scattering lengths, and more.« less
Comparison of heuristic approaches to the generalized tree alignment problem

Two commonly used heuristic approaches to the generalized tree alignment problem are compared in the context of phylogenetic analysis of DNA sequence data. These approaches, multiple sequence alignment + phylogenetic tree reconstruction (MSA+TR) and direct optimization (DO), are alternative heuristic procedures used to approach the nested NP-Hard optimizations presented by the phylogenetic analysis of unaligned sequences under maximum parsimony. Multiple MSA+TR implementations and DO were compared in terms of optimality score (phylogenetic tree cost) over multiple empirical and simulated datasets with differing levels of heuristic intensity. In all cases examined, DO outperformed MSA+TR with average improvement in parsimony score of 14.78% (5.64-52.59%).
Temporal and spatial spread of an intersegmental reflex in crayfish

SUMMARY An intersegmental reflex initiated by flexing a crayfish leg at the merocarpal joint was examined by recording reflex response latencies of cephalic, thoracic and abdominal muscles. The first response was an intrasegmental resistance reflex in the extensor muscle of the stimulated leg. Spread of the intersegmental reflex occurred in both cephalic and caudal directions. Activation of the cephalic appendages occurred first (antennal levators, with latencies of 14-18 ms) while the abdominal musculature was activated last (superficial extensors, with latencies of 51-62ms). Shift of the stimulus site from the second to the fifth leg resulted in shorter latencies of the fifth leg and abdominal muscle responses while the latency for second leg extensor muscle discharge increased. Low correlation coefficients between the response latencies of pairs of cephalic and abdominal muscles, and thoracic and abdominal muscles, indicate that reflex pathways which initiate the abdominal responses are different from those that evoke the cephalic and thoracic responses. High correlation coefficients indicate common reflex pathways for activating either ipsilateral or contralateral pairs of extensors or flexors in the second and fifth legs. High correlations suggesting common reflex pathways or cross-coupling were also obtained for bilateral pairs of abdominal extensors. Low correlation coefficients for the response latencies of paired muscles indicate separate reflex pathways for (1) bilaterally homologous leg muscles and (2) first-fifth segment abdominal extensors. Surgical isolation of the supraoesophageal ganglion from the ventral nerve cord eliminated the responses of the antennal levators while producing a substantial increase in the response latencies of both maxilliped extensors and the contralateral second leg extensor and flexor, as well as a small but significant decrease in the contralateral first abdominal extensor. The synaptic input zones of the interneurones that mediate the thoracic and abdominal responses are located in the ventral nerve cord and not in the supraoesophageal ganglion.
Reducing the effect of the ball on bat performance measurements

A simple physical model is presented that relates the ball–bat coefficient of restitution e to the ball coefficient of restitution e 0 and dynamic stiffness k 0. The model is used to develop a technique to normalize e to values of e 0 and k 0 for a “standard ball.” The efficacy of this normalization technique is demonstrated by comparison with experimental data. It is shown to be vastly superior to a widely used technique that is based on the physically unjustified assumption that the ratio e/e 0, commonly referred to as the Bat Performance Factor or BPF, is independent of both e 0 and k 0. A residual, but much reduced, dependence of the normalized e on k 0 is observed and is shown through finite element simulations to be due to a dependence of the bat stiffness on the ball stiffness.
Differential effect of zinc finger deletions on the binding of CTCF to the promoter of the amyloid precursor protein gene

High levels of transcription from the amyloid precursor protein promoter are dependent on the binding of CTCF to the APBbeta core recognition sequence located between positions -82 and -93 upstream from the transcriptional start site. CTCF comprises 727 amino acids and contains 11 zinc finger motifs arranged in tandem that are flanked by 267 amino acids on the N-terminal side and 150 amino acids on the C-terminal side. Deletion of either the N- or the C-terminal regions outside of the zinc finger domain had no detrimental effect on the binding of CTCF to APBbeta. However, internal deletions of zinc fingers 5-7 completely abolished binding. The binding of full-length CTCF generated a DNase I protected domain extending from position -78 to -116, which was interrupted by a hypersensitive site at position -99. Selective deletions from the N- and C-terminal sides of the zinc finger domain showed that the N-terminal end of the zinc finger domain was aligned toward the transcriptional start site. Furthermore, deletions of zinc fingers peripheral to the essential zinc fingers 5-7 decreased the stability of the binding complex by interrupting sequence-specific interactions.
Kinetics of tumor growth of prostate carcinoma estimated using prostate-specific antigen.

Abstract Objectives To investigate whether the second-order kinetics model of prostate-specific antigen (PSA) increase would be more appropriate in some cases than the traditionally assumed first-order model. PSA levels are used to detect tumor recurrence after radical prostatectomy, and the rate of PSA increase is used to predict patients’ prognosis. Methods Sequential PSA values from 147 patients showing detectable PSA after radical prostatectomy were analyzed by nonlinear regression analysis. The best-fitting model was chosen using the lowest sum of squares residual error. Results Of the 147 cases, 90 (61.2%) followed the first-order kinetics, and 57 (38.8%) were better described by second-order kinetics. The order of PSA increase correlated with the Gleason score of the tumor in the radical prostatectomy specimens. The first-order kinetics were associated with tumors with Gleason scores of 5 to 6, 7, and 9, and the second-order kinetics were associated with tumors with a Gleason score of 8 ( P Conclusions The presence of a group of tumors in which the increase in PSA follows second-order kinetics is significant. Such an increase may be associated with an autocatalytic mechanism assisting tumor growth. The existence of such a mechanism requires additional investigation.
Multiple Sequence Comparison and n-Dimensional Image Reconstruction

Calculation of dot-matrices is a widespread tool in pairwise sequence comparison. In recent studies the usefulness of dot-matrices for multiple sequence alignment has been proved. Viewing dot-matrices as projections of unknown n-dimensional points, we consider the multiple alignment problem (for n sequences) as an n-dimensional image reconstruction problem with noise. From this perspective we introduce and develop the filtering method due to Vingron and Argos (J. Mol. Biol. (1991), 218, pp. 33–43). We discuss a conjecture of theirs regarding the number of iterations their algorithm requires and demonstrate that this number may be large. An improved version of the original algorithm is introduced that avoids costly dot-matrix multiplications and runs in O(n3·L3) time (L is the length of the longest sequence). This is equivalent to only one iteration of the original algorithm. We also discuss applications to DNA/protein sequence comparisons.
ACQUISITION, PROCESSING, AND PRESENTATION OF 3-D CHROMATOVOLTAMMOGRAPHIC DATA USING AN IBM PS/2 AND PAR MODEL 273 POTENTIOSTAT

Abstract A software package for interfacing an IBM PS/2 and the EG&G PAR model 273 potentiostat/galvanostat is described. The software is capable of controlling the instrument and taking and displaying both potential and current data simultaneously as a function of time (chromatovoltammetry). The software is written in both Microsoft QuickBASIC and QuickC for fast operation and easy portability. The software can also be easily modified to provide user-friendly control of the PAR 273 potentiostat for a multitude of other computer-controlled electrochemical experiments. An application is described for the determination of catecholamines using high-performance liquid chromatography with a carbon fiber ultramicroelectrode and square wave voltammetry for detection.
On the equivalence of PLSI and projected clustering

The problem of projected clustering was first proposed in the ACMSIGMOD Conference in 1999, and the Probabilistic Latent Semantic Indexing (PLSI) technique was independently proposed in the ACMSIGIR Conference in the same year. Since then, more than two thousand papers have been written on these problems by the database, data mining and information retrieval communities, along completely independent lines of work. In this paper, we show that these two problems are essentially equivalent, under a probabilistic interpretation to the projected clustering problem. We will show that the EM-algorithm, when applied to the probabilistic version of the projected clustering problem, can be almost identically interpreted as the PLSI technique. The implications of this equivalence are significant, in that they imply the cross-usability of many of the techniques which have been developed for these problems over the last decade. We hope that our observations about the equivalence of these problems will stimulate further research which can significantly improve the currently available solutions for either of these problems.