cssi/SciSciGPT-SciSciNet huggingface dataset:
The influence of herbivory on plant cover and species composition in the Pryor Mountain Wild Horse Range, USA

We investigated the effects of short- and long-term ungulate grazing on plant species cover and composition in arid lowland and more mesic upland communities of the Pryor Mountain Wild Horse Range (PMWHR). Measurements were taken over two years which differed significantly in growing season precipitation. Interannual differences in plant cover were significantly greater than differences between grazed and ungrazed communities. In the arid lowlands total plant cover decreased from 47% in 1993, a relatively wet year, to 29% in 1994, a relatively dry year. In the more mesic uplands total plant cover decreased from 107% in 1993 to 56% in 1994. The magnitude of change in cover was greatest in the grasses, especially for Pseudoroegneria spicata, the most abundant species in the lowland communities, which decreased from 21% cover in 1993 to 11% in 1994. There was not a consistent effect of herbivory on plant cover across sites, but its effects, particularly on the dominant perennial grasses, were conspicuous at some sites. For instance, in the lowlands cover of P. spicata was 3–12% in long-term grazed sites and 9–28% in short- to long-term ungrazed sites. Our study indicates that abiotic factors (e.g., precipitation) are more likely than grazing to affect abundances of key plant species, and hence ecosystem dynamics, in the PMWHR, and that the effects of herbivory are more localized and more prevalent in the lowland grasses than in the other plant functional groups.
The adjustment process of accruals: Empirical evidence and implication for accrual research

This study analyzes the intertemporal behavior of accruals and uses the results to offer some perspectives on models of accruals. Separate adjustment rates are estimated for total and managed accruals and further compared to assess the influence of managers on accrual adjustment. Analysis is further performed to test whether there is an industry-specific adjustment rate for either total or managed accruals. The results show that both the total and managed accruals follow a partial adjustment process rather than a pure-adjustment or random-walk process. Nonetheless, managed accruals exhibit longer adjustment length than total accruals in each industry sample. In addition, total and managed accruals appear to follow certain adjustment patterns that are industry-specific, consistent with the view that common industry practices and norms lead to benchmark adjustment rates to which industry firms conform. Based on the results showing that accruals exhibit lagged and industry-specific adjustments, an extension of the modified Jones model is proposed. The extended model incorporates lagged accruals and an industry accrual index in an attempt to exploit the lagged-adjustment and industry effects and, in that context, improve the temporal classification of accrual innovations. Simple tests show that the extended model achieves substantial improvements in specification over the modified Jones model.
Intelligent visualization and exploration of time-oriented clinical data

We describe a conceptual architecture and software implementation specific to the task of interpretation, summarization, visualization, explanation, and interactive exploration of time oriented clinical data and the multiple levels of meaningful concepts that can be abstracted from these data. We build on our work on abstraction of time oriented clinical data using a knowledge base, acquired from clinical experts, of temporal properties of the data. We call the new framework KNAVE (Knowledge-based Navigation of Abstractions for Visualization and Explanation). The visualization and exploration operators whose semantics are domain independent, access the domain specific knowledge base. Exploration exploits key relations (e.g., the abstraction hierarchy) in each clinical domain. Preliminary assessment of the prototype with several clinical users has been encouraging. The KNAVE methodology has broad ramifications for reducing the load that large numbers of time oriented clinical data put on practising physicians.
Stress: Psychological Perspectives

Psychological stress is a popular term denoting processes believed to contribute to the onset and maintenance of a variety of mental and physical conditions. Despite widespread interest in psychological stress and its consequences for health and well-being, debate remains about how to best define the term. Three perspectives for defining and studying psychological stress are reviewed with respect to their history, development, and current status. These three perspectives on psychological stress differ in terms of the relative emphasis each places on the environment, the organism, and the interaction between the organism and environment over time. Conceptual and methodological considerations and implications of the three perspectives are reviewed. Recent elaborations of the concept of stress that attempt to expand its biological consequences over time are also discussed. Finally, promising topics for future inquiry on psychological stress are addressed.
Large-scale EST sequencing in rice

Large-scale cDNA analysis provides several great advantages for genome investigations in rice. Isolated and partially characterized cDNA clones have contributed not only to the construction of an RFLP linkage map and physical maps of the chromosomes but also to investigations of the mechanisms of expression of various isozymes and family genes. The ultimate aim of our large-scale cDNA analysis is to catalogue all the expressed genes of this important cereal, including tissue-specific, developmental stage-specific, and stress-specific genes. As of August 1996, the Rice Genome Research Program (RGP) has isolated and partially sequenced more than 29 000 cDNA clones from various tissues and calluses in rice (Nipponbare, a japonica variety). The sequence data were translated into amino acid sequences for the 3 possible reading frames, and the similarity of these amino acid sequences to known proteins registered in PIR were examined. About 25% of the clones had significant similarities to known proteins. Some of the hit clones showed library-specific distributions, indicating that the composition of the clones in each library reflects, to some extent, the regulation of gene expression specific to differentiation, growth condition, or environmental stress. To further characterize the cDNA clones, including unknown clones, nucleotide sequence similarities of 24 728 clones were analyzed and the clones were classified into around 10 000 independent groups, suggesting that around a half or one third of expressed genes in rice have already been captured. These results obtained from our large-scale cDNA analysis provide useful information related to gene expression and regulation in rice.
Signals from the reproductive system regulate the lifespan of C. elegans

Understanding how the ageing process is regulated is a fascinating and fundamental problem in biology. Here we demonstrate that signals from the reproductive system influence the lifespan of the nematode Caenorhabditis elegans. If the cells that give rise to the germ line are killed with a laser microbeam, the lifespan of the animal is extended. Our findings suggest that germline signals act by modulating the activity of an insulin/IGF-1 (insulin-like growth factor) pathway that is known to regulate the ageing of this organism. Mutants with reduced activity of the insulin/IGF-1-receptor homologue DAF-2 have been shown to live twice as long as normal, and their longevity requires the activity of DAF- 16, a member of the forkhead/winged-helix family of transcriptional regulators. We find that, in order for germline ablation to extend lifespan, DAF-16 is required, as well as a putative nuclear hormone receptor, DAF-12. In addition, our findings suggest that signals from the somatic gonad also influence ageing, and that this effect requires DAF-2 activity. Together, our findings imply that the C. elegans insulin/IGF-1 system integrates multiple signals to define the animal's rate of ageing. This study demonstrates an inherent relationship between the reproductive state of this animal and its lifespan, and may have implications for the co-evolution of reproductive capability and longevity.
Dimensional reduction of duplex DNA under confinement to nanofluidic slits

There has been much interest in the dimensional properties of double-stranded DNA (dsDNA) confined to nanoscale environments as a problem of fundamental importance in both biological and technological fields. This has led to a series of measurements by fluorescence microscopy of single dsDNA molecules under confinement to nanofluidic slits. Despite the efforts expended on such experiments and the corresponding theory and simulations of confined polymers, a consistent description of changes of the radius of gyration of dsDNA under strong confinement has not yet emerged. Here, we perform molecular dynamics (MD) simulations to identify relevant factors that might account for this inconsistency. Our simulations indicate a significant amplification of excluded volume interactions under confinement at the nanoscale due to the reduction of the effective dimensionality of the system. Thus, any factor influencing the excluded volume interaction of dsDNA, such as ionic strength, solution chemistry, and even fluorescent labels, can greatly influence the dsDNA size under strong confinement. These factors, which are normally less important in bulk solutions of dsDNA at moderate ionic strengths because of the relative weakness of the excluded volume interaction, must therefore be under tight control to achieve reproducible measurements of dsDNA under conditions of dimensional reduction. By simulating semi-flexible polymers over a range of parameter values relevant to the experimental systems and exploiting past theoretical treatments of the dimensional variation of swelling exponents and prefactors, we have developed a novel predictive relationship for the in-plane radius of gyration of long semi-flexible polymers under slit-like confinement. Importantly, these analytic expressions allow us to estimate the properties of dsDNA for the experimentally and biologically relevant range of contour lengths that is not currently accessible by state-of-the-art MD simulations.
Physical Properties of Inverse-Phosphocholine Lipids

Recently a novel class of lipids has been synthesized, namely Zwitterionic inverse-phsophocholine (iPC) lipids. These lipids contain head groups with an inverted charge orientation with respect to phosphocholine (PC) lipids. The inversion of the dipole moment of the headgroup is expected to have dramatic effects on local electrostatics, which can affect their ability to transport ions and electroporate. We used molecular dynamic simulations to investigate the physical properties of two iPC lipid bilayers whose headgroups have a quaternary amine adjacent to the bilayer interface and a phosphate that extends into the aqueous phase. Specifically, we focus on the profile of the transmembrane potential and compare it to that of POPC, and find that it is positive and on the same order as POPC. We also find that the lipid and water components of the electric potential profile of iPC lipids are inverted and have different magnitudes with respect to POPC. To rationalize these similarities and differences, we perform an analysis of their charge density distributions.
Does copper (II) ethylenediaminetetraacetate disproportionate superoxide

W. M. Willingham and J. R. J. Sorenson have recently reported [1988) Biochem. Biophys. Res. Commun. 150, 252-258) that the Cu(II)EDTA complex catalyzes the dismutation of O-2 and thereby call into question several earlier reports. These authors concluded that the widespread use of EDTA to suppress dismutation of O-2 by adventitious Cu(II) and other metals, during assays for superoxide dismutase, is unsound. We have undertaken a clarification of this issue by examining the ability of Cu(II)EDTA to catalyze the dismutation of O-2 and have found this complex to be devoid of this activity at pH 6.0 or at 7.8; whether assayed by the cytochrome c or the nitroblue tetrazolium assays. The probable reasons for the results of Willingham and Sorenson and some peculiarities of the nitroblue tetrazolium assay have been explored.
Building schools, rethinking quality? Early lessons from Los Angeles

Purpose – Newly designed schools for centuries have projected fresh ideals regarding how children should learn and how human settlements should be organized. But under what conditions can forward‐looking architects or education reformers trump the institutionalized practices of teachers or the political‐economic constraints found within urban centers? The purpose of this paper is to ask how the designers of newly built schools in Los Angeles – midway into a $27 billion construction initiative – may help to rethink and discernibly lift educational quality. This may be accomplished via three causal pathways that may unfold in new schools: attracting a new mix of students, recruiting stronger teachers, or raising the motivation and performance of existing teachers and students.Design/methodology/approach – We track basic indicators of student movement and school quality over a five‐year period (2002‐2007) to understand whether gains do stem from new school construction. Qualitative field work and interviews ...
Medication administration variances before and after implementation of computerized physician order entry in a neonatal intensive care unit.

OBJECTIVE. The goal was to determine whether implementation of a computerized physician order entry system was associated with a decrease in medication administration variances in a NICU. METHODS. A prospective observational study was conducted. Research nurses recorded details of medication administrations for patients in a NICU during standardized observation periods. Details of each administration were compared with the medication order; a variance was defined as a discrepancy between the order and the medication administration. Rates of variances before and after implementation of computerized physician order entry in the NICU were compared. Specific types of and reasons for variances were also compared. RESULTS. Data on 526 medication administrations, including 254 during the pre-computerized physician order entry period and 272 after implementation of computerized physician order entry, were collected. Medication variances were detected for 19.8% of administrations during the pre-computerized physician order entry period, compared with 11.6% with computerized physician order entry (rate ratio: 0.53). Overall, administration mistakes, prescribing problems, and pharmacy problems accounted for 74% of medication variances; there were no statistically significant differences in rates for any of these specific reasons before versus after introduction of computerized physician order entry. Administration of a medication at the wrong time accounted for 53.1% of all variances. Variance rates related to giving a drug at the wrong time were significantly lower in the computerized physician order entry period than in the pre-computerized physician order entry period (rates: 6.7% and 9.9%, respectively; rate ratio: 0.53). CONCLUSIONS. Implementation of computerized physician order entry in a NICU was associated with a significant decrease in the rate of medication administration variances. However, even with the use of computerized physician order entry, variances were noted for >11% of all medication administrations, which suggests that additional methods may be needed to improve neonatal patient safety.
An Interpreter’s Interpretation: Sign Language Interpreters’ View of Musculoskeletal Disorders

Introduction: Sign language interpreters are at increased risk for musculoskeletal disorders associated with work. Previous studies have used survey techniques to identify potential risk factors and approaches to their medical management. Little is known about risk factors and management of symptoms in this group from the perspective of the interpreter. Such qualitative information should help inform future research related to this professional group. Method: One thousand ninety-two sign language interpreters recruited from the Registry of Interpreters for the Deaf completed an open-ended question that was a component of a national prevalence survey. Responses were evaluated using content analysis. Inter and intra rater reliability were high (.88 and .92, respectively). Results: Risk factors for initiation and/or exacerbation of symptoms included: difficult job, interpreting setting (educational), interpreting style (e.g., posture, self generated force), and emotional and physical stressors. Exercise (e.g., stretching, aerobics) was a common prevention strategy. Conventional medical treatment was used as the first line approach to symptom control. Self-care methods such as exercise, diet and warm up prior to interpreting were also reported. While massage and chiropractic care was used as commonly as in the general population, acupuncture was found to be used more often. Coping strategies that were more active (e.g. exercise, diet, more control over work schedule) were also reported as useful. Conclusions: These findings provide a description of factors that interpreters view as important in the development and exacerbation of hand and wrist pain. The results also indicate that interpreters used many self-management approaches. Future research should carefully investigate the utility of such approaches using well-controlled designs. Also, because of its widespread use in this group the evaluation of acupuncture in the management of these symptoms appears warranted. The qualitative approach used in the present study permitted an analysis of the worker perspectives regarding risk and management of these work related symptoms. This information can be used to further inform future research.
An alternative technique for treatment of choledocholithiasis found at laparoscopic cholecystectomy

Objective: To introduce a new strategy for dealing with abnormal cholangiograms at laparoscopic cholecystectomy that makes postoperative cholangiograms possible and facilitates stone extraction by assuring access to the duct for a guide-wire—assisted endoscopic retrograde sphincterotomy. Design: Retrospective review of a prospectively maintained database. Patients: Twenty-four patients with abnormal cholangiograms had a percutaneously placed double-lumen catheter threaded through the cystic duct and advanced into the duodenum. Results: Ten successful guide-wire—assisted endoscopic retrograde sphincterotomies were performed without complications. Eleven normal postoperative cholangiograms suggested spontaneous stone passage or false-positive intraoperative cholangiograms. There were three technical failures in the early part of the series. Conclusions: This strategy is a reasonable alternative to laparoscopic common bile duct exploration (1) when the cholangiogram is questionably positive, (2) when prolonged anesthesia (poor-risk patient) should be avoided, (3) when the equipment for laparoscopic common bile duct exploration is not available, and (4) when spontaneous stone passage seems likely. Postoperative endoscopic retrograde sphincterotomy with stone extraction is facilitated when it becomes necessary because a guide wire can be introduced through the catheter. (Arch Surg. 1995;130:638-642)
Bit-Wise MTNCL: An ultra-low power bit-wise pipelined asynchronous circuit design methodology

This paper develops an ultra-low power design methodology for bit-wise pipelined asynchronous circuits, called bit-wise MTNCL, which combines multi-threshold CMOS (MTCMOS) with bit-wise pipelined NULL Convention Logic (NCL) systems. Compared to original NCL circuits implemented with all low-Vt and high-Vt transistors, respectively, it provides the leakage power advantages of the all high-Vt NCL implementation with a reasonable speed penalty compared to the all low-Vt design, requires less energy/operation, and has no area overhead.
The protective effect of AIDS-related behavioral change among injection drug users: A cross-national study

OBJECTIVE: This study assessed the relationship between self-reported acquired immunodeficiency syndrome (AIDS) behavioral change and human immunodeficiency virus (HIV) serostatus among injection drug users. METHODS: The study sample involved 4419 injection drug users recruited from drug abuse treatment and nontreatment settings in 11 cities in North America, South America, Europe, Asia, and Australia. The World Health Organization multisite risk behavior questionnaire was used, and either blood or saliva samples for HIV testing were obtained. Subjects were asked, "Since you first heard about AIDS, have you done anything to avoid getting AIDS?" RESULTS: The protective odds ratio for behavioral change against being infected with HIV was 0.50 (95% confidence interval = 0.42, 0.59). While there was important variation across sites, the relationship remained consistent across both demographic and drug use history subgroups. CONCLUSIONS: Injection drug users are capable of modifying their HIV risk behaviors an...
Cochlear IgG in the C3H/lpr autoimmune strain mouse

Abstract The inner ear of the C3H/lpr autoimmune strain mouse was evaluated to identify potential mechanisms by which systemic autoimmune disease interferes with auditory function. The inner ears were immunohistochemically stained for IgG at ages before (2 months) and after (6–10 months) autoimmune disease onset and compared to age-matched nonautoimmune C3H/HeJ controls. Immunoreactivity for IgG was not seen in the 2 month C3H/lpr autoimmune mice or in either age group of the C3H/HeJ controls. On the other hand, all older C3H/lpr mice showed reaction product in the vessels of the cochlea, particularly the stria vascularis and bony capsule. Less frequent sites of staining were the geniculate ganglion, marrow cavities of the bony capsule, tensor tympani muscle, and on one occasion, a hair cell of the organ of Corti. These findings indicate that IgG is widespread within the cochlea and its vessels during systemic autoimmune disease and not directed against any specific sensorineural structure. This suggests a generalized or indirect mechanism whereby such systemic disease affects the inner ear.
Minimal-volume projections of cubes and totally unimodular matrices

Abstract Among all linear projections onto a given linear subspace L in R n we select those that minimize the volume of the image of the cube {x:|xi|⩽1}. The paper is devoted to a description of the shape of such images of the cube. The shape is characterized in terms of zonotopes spanned by scalar multiples of rows of totally unimodular matrices.
Top-of-atmosphere radiative contribution to unforced decadal global temperature variability in climate models

Much recent work has focused on unforced global mean surface air temperature (T) variability associated with the efficiency of heat transport into the deep ocean. Here the relationship between unforced variability in T and the Earth's top-of-atmosphere (TOA) energy balance is explored in preindustrial control runs of the Coupled Model Intercomparison Project Phase 5 multimodel ensemble. It is found that large decadal scale variations in T tend to be significantly enhanced by the net energy flux at the TOA. This indicates that unforced decadal variability in T is not only caused by a redistribution of heat within the climate system but can also be associated with unforced changes in the total amount of heat in the climate system. It is found that the net TOA radiation imbalances result mostly from changes in albedo associated with the Interdecadal Pacific Oscillation that temporarily counteracts the climate system's outgoing longwave (i.e., Stefan-Boltzmann) response to T change.
Mayoral Leadership Matters: Lessons Learned From Mayoral Control of Large Urban School Systems

“Mayoral takeover” has emerged as a major reform option for struggling urban districts since it was launched in Boston in 1992 and Chicago in 1995. This article examines the design, implementation, and the effects of mayoral-led school systems. Our research addresses issues that are critical to systemwide improvement: Are there variation in how mayors govern their schools? How can mayors “add values” to current school reform efforts in their cities? Have more resources been provided for teaching and learning? Is the public more confident in their city's school system? Are test scores improving? In addressing these issues of student outcomes and management improvement, we highlight lessons learned from our research project's mixed-methods approach, including case studies and statistical analyses using a multiyear database on a purposeful sample of 100 urban districts.
Minimizing roundoff errors of prefix sums via dynamic construction of Huffman trees

The prefix-sum operation, which returns all prefix sums on a sequence of numbers, plays an important role in many applications. We study how to efficiently evaluate prefix sums on positive floating-point numbers such that the worst-case roundoff error of each sum is minimized. A direct approach to this problem builds a Huffman tree for each prefix subsequence from scratch, requiring exactly quadratic time for every input X. We can do better by taking advantage of the current Huffman tree to build the next Huffman tree, using dynamic insertions and deletions on Huffman trees. Consequently, subquadratic time suffices for various input patterns. We also provide experimental comparisons of all the algorithms studied in this paper on inputs that are randomly and uniformly generated.
Steady state simulation analysis: importance sampling using the semi-regenerative method

We discuss using the semi-regenerative method, importance sampling, and stratification to estimate the expected cumulative reward until hitting a fixed set of states for a discrete-time Markov chain on a countable state space. We develop a general theory for this problem and present several central limit theorems for our estimators. We also present some empirical results from applying these techniques to simulate a reliability model.
Nuclear Factor-κB-inducing Kinase (NIK) Contains an Amino-terminal Inhibitor of Apoptosis (IAP)-binding Motif (IBM) That Potentiates NIK Degradation by Cellular IAP1 (c-IAP1)

Activation of the noncanonical NF-κB pathway hinges on the stability of the NF-κB-inducing kinase (NIK), which is kept at low levels basally by a protein complex consisting of the E3 ubiquitin ligases cellular inhibitor of apoptosis 1 and 2 (c-IAP1/2) proteins and the tumor necrosis factor receptor-associated factors 2 and 3 (TRAF2/3). NIK is brought into close proximity to the c-IAPs through a TRAF2-TRAF3 bridge where TRAF2 recruits c-IAP1/2 and TRAF3 binds to NIK. However, it is not clear how the c-IAPs specifically recognize and ubiquitylate NIK in the complex. We have identified an IAP-binding motif (IBM) at the amino terminus of NIK. IBMs are utilized by a number of proapoptotic proteins to antagonize IAP function. Here, we utilize mutational studies to demonstrate that wild-type NIK is destabilized in the presence of c-IAP1, whereas the NIK IBM mutant is stable. NIK interacts with the second baculovirus IAP repeat (BIR2) domain of c-IAP1 via the IBM, and this interaction, in turn, provides substrate recognition for c-IAP1 mediated ubiquitylation and degradation of NIK. Furthermore, in the presence of the NIK IBM mutant, we observed an elevated processing of p100 to p52 followed by increased expression of NF-κB target genes. Together, these findings reveal the novel identification and function of the NIK IBM, which promotes c-IAP1-dependent ubiquitylation of NIK, resulting in optimal NIK turnover to ensure that noncanonical NF-κB signaling is off in the absence of an activating signal.
Mice expressing human mutant presenilin-1 exhibit decreased activation of NF-κB p50 in hippocampal neurons after injury

Abstract Mutations in the presenilin-1 (mutPS-1) gene, a cause of familial Alzheimer’s disease, increase the susceptibility of neurons to apoptotic death. Using the trimethyltin model of hippocampal neurodegeneration, mice expressing the human mutPS-1 gene (M146L) exhibited increased neurodegeneration and mortality relative to non-transgenic littermates. Activation of NF-κB p50 was found to be impaired in transgenic mice with unaltered expression levels suggesting that mutPS-1 expression inhibits p50 activation to adversely affect neuronal resistance to injury.
Labdane diterpenoids from Grindelia discoidea (asteraceae)

Abstract The dichloromethane extract of the aerial parts of Grindelia discoidea afforded three new labdane diterpenoids: cordobic acid, cordobic acid 18-acetate and 7-epicordobic acid. The structures of these new isolates were deduced mainly from their spectral data, using comparisons with one another and with other labdanoids including discoidic acid, a constituent of G. discoidea reported earlier.
Dynorphin-(1–13) induces spontaneous feeding in rats

Abstract Dynorphin-(1–13), a recently isolated opioid peptide stimulates food ingestion in rats after intracerebroventricular administration at doses of 1 and 10 μg. The latency until food ingestion is 22.4 ± 1.9 min. The ability of dynorphin-(1–13) to initiate food ingestion is antagonized by the opiate antagonist, naloxone. The food ingestion is accompanied by excessive grooming behavior.
Acute Effects of Ozone on Heart Rate and Body Temperature in the Unanesthetized, Unrestrained Rat Maintained at Different Ambient Temperatures

AbstractThe present studies were conducted to investigate the concentration-response characteristics of acute ozone (O3) exposure on the cardiovascular and thermoregulatory function of the unanesthetized, unrestrained rat, and to examine the modulating effects produced by changes in ambient temperature (T a) on the induced toxic response. For all studies, groups of male Fischer 344 rats (n - 4-6/group) were implanted with radiotelemetry transmitters and allowed to recover overnight. The transmitters permitted continuous monitoring of electrocardiogram (ECG) and body core temperature (T co); heart rate (HR) was derived from the ECG signal. Frequency of breathing (f) was obtained in selected experiments using a barometric plethysmograph. All animals were monitored according to the following protocol: control (filtered air, 0.25 hr); exposure (O3, 2 hr); recovery (filtered air, 3–18 hr). For the concentration-response experiments, O3 concentration was varied from 0.25 to 1.0 ppm and all exposures were conduc...
Mechanism of Soluble Epoxide Hydrolase FORMATION OF AN α-HYDROXY ESTER-ENZYME INTERMEDIATE THROUGH Asp-333

18O-Labeled epoxides of trans-1,3-diphenylpropene oxide (tDPPO) and cis-9,10-epoxystearic acid were synthesized and used to determine the regioselectivity of sEH. The nucleophilic nature of sEH catalysis was demonstrated by comparing the enzymatic and nonenzymatic hydrolysis products of tDPPO. The results from single turnover experiments with greater or equal molar equivalents of sEH:substrate were consistent with the existence of a stable intermediate formed by a nucleophilic amino acid attacking the epoxide group. Tryptic digestion of sEH previously subjected to multiple turnovers with tDPPO in H218O resulted in the isolation and purification of a tryptic fragment containing Asp-333. Electrospray mass spectrometry of this fragment conclusively illustrated the incorporation of 18O. After complete digestion of the latter peptide it was shown that Asp-333 of sEH exhibited an increased mass. The attack by Asp-333 initiates enzymatic activity, leading to the formation of an α-hydroxyacyl-enzyme intermediate. Hydrolysis of the acyl-enzyme occurs by the addition of an activated water to the carbonyl carbon of the ester bond, after which the resultant tetrahedral intermediate collapses, yielding the active enzyme and the diol product.
kMc/s planar transistors in microwatt logic circuitry

Abstract A new ultra-high-frequency transistor having a maximum frequency of oscillation of over 1 kMc/s and a gain-bandwidth product of about 800 Mc/s is described. It also has extremely low-leakage and usable d.c. current gain down to 1 μA and is seen to offer special advantages for application at extremely low current levels in logic circuitry. At the same time, owing mainly to the low collector capacitance of 0·6 pF (excluding the case), it is capable of operating at switching speeds of from 100 kc/s to 1 Mc/s at collector currents of 1–10 μA, respectively. Diode-transistor logic, in general, and a new form using backward diodes, in particular, are seen to offer advantages in conservation of fan-in and fan-out at a given current level. This is especially important as the level is reduced. The latter form offers in addition a saving in number of components required. D.C. conditions necessary to assure operation are considered, and it is seen that the circuits are feasible if the proper balance between diode and transistor voltages may be achieved. If not, then compensated circuits, using extra diodes either in series or as clamping elements, enable operation. The desirable features of a device which would satisfy the requirements are illustrated by the characteristic curve of an experimental silicon backward diode. Performance is further demonstrated by a working four-stage shift register designed around a basic building block operating at 10 μA per transistor stage. The shift register operates satisfactorily at 200 kc/s from −40 to +100°C. It draws a total of about 360 μA. A computer using 10,000 such stages would draw a total current of about 100 mA at a power level of 300 mW.
Photoreflectance Probing of Below Gap States in Gan/Algan High Electron Mobility Transitor Structures

Optical Impedence Spectroscopy of GaN/AlGaN high electron mobility transistor structures (HEMTs) using photoreflectance exhibit a photoreflectance lags – the component of the modulated reflectance out of phase with the chopper – ranging from 0.1 to 0.5. Photoreflectance was performed using below gap pumping on various samples. Samples that do exhibit appreciable photoreflectance lag for above gap pumping show significantly enhanced photoreflectance signals for below gap pumping. Yet, samples that do not exhibit appreciable photoreflectance lag for above gap pumping do not exhibit a signal for below gap pumping. This implies that the photoreflectance phase lag is due to mid-gap trap states. At least 2 types of traps are found, above and below about 2.5 eV. This result means that that photoreflectance can be used as a probe of HEMT device quality.
The effects of photoperiod manipulation on the reproduction of black sea bass, Centropristis striata

The black sea bass, Centropristis striata, is a potential candidate for commercial aquaculture in the United States. One of the most significant constraints limiting commercial production of black sea bass is the lack of a reliable supply of eggs and larvae. A narrow window of annual spawning prevents year-round availability of juveniles for grow out. The present study reports on the use of photoperiod manipulation to alter the timing of spawning in C. striata and increase availability of larvae. Adult black sea bass were maintained under a simulated natural (SNP) or an accelerated long day (ALD) photoperiod regimen. Water temperature was adjusted from 14 to 20 °C to correspond to seasonal changes in daylength. Reproductive development was monitored by histological analysis of gonadal biopsies and plasma levels of sex steroids (estradiol-17β, testosterone and 11-ketotestosterone). Females in both regimens were induced to spawn by implantation of 25 μg luteinizing hormone-releasing hormone analogue (LHRHa) when follicle diameters exceeded 500 μm. Acceleration of the photoperiod advanced the annual cycle of circulating gonadal steroids in both sexes without altering the profile. The onset of spermiation in males was unaffected by photoperiod manipulation, but follicle growth and spawning in females were advanced approximately 2 months by exposure to the ALD regimen. Of interest, the ALD photoperiod regimen accelerated the time frame of sexual succession from female to male without reducing the mean volume of eggs produced per female. These findings suggest that photoperiod manipulation can be used to alter the timing of reproduction in black sea bass and increase the supply of eggs for commercial aquaculture.
A comparative study of the preparation and properties of ribonucleic acids of yeast.

Abstract Highly purified preparations of ribonucleic acid have been obtained from baker's yeast employing newly modified methods of isolation. Solubility studies show that these materials are inhomogeneous, apparently containing a range of molecular structures of varying weight, and a dependence of solubility on molecular size is reported. It is suggested that homogeneous samples have never been obtained from cells. In addition, it is proposed tentatively that normal yeast cells possess a variety of ribonucleic acids and that known isolation methods modify the native structures thereby adding to the complexity of isolated preparations. The foregoing conclusion is supported by solubility studies designed to compare qualitatively the compositions of two different preparations of ribonucleic acid by examining an experimental mixture of these samples. The presence of common components in otherwise dissimilar and inhomogeneous preparations is suggested. Number-average molecular weights are reported for the various preprations with a value in one case of 66,000 after prolonged dialysis at 0 °C. This average size exceeds any recorded for preparations of the ribonucleic acid of yeast.
Confocal microscope with enhanced depth discrimination

ABSTRACT Confocal microscopy, in comparison to conventional microscopy, offers a narrower point-spread function, the rendition of phase structures in contrast, and high axial resolution. Of these, the capabilities of optical sectioning and the three-dimensional imaging of cells and tissues have attractedthe most interest. The literature offers a number of studies exploring the factors affecting depth offield in confocal microscopy.13 In this article, the three-dimensional representation of fluorescenceimagery is examined and the design of a laser scanning confocal fluorescence microscope withenhanced depth discrimination is described. 1 . THE CONFOCAL MICROSCOPE The layout of the confocal microscope is shown in Fig. 1 . A laser beam of short-wavelengthexcitation light enters through an optical subsystem that controls the beam's spherical aberration. Thisscheme provides image correction corresponding to a correction for tube length in a conventionalmicroscope. The spherical aberration corrector is an afocal, unit-magnification triplet, thereforerepositioning its elements during adjustment does not affect beam focus. The correction also willallow compensation for spherical aberration introduced by deviations in the thickness of the specimencover glass.Confocal microscope with enhanced depth discriminationR. Shack, P. H. Bartels, D. Hillman, M. Sabb, and R. ShoemakerOptical Sciences Center, University of Arizona, Tucson, Arizona 85721
Proteolytic processing of NF-kappa B/I kappa B in human monocytes. ATP-dependent induction by pro-inflammatory mediators.

Abstract Proteolytic processing of select constituents of the nuclear factor κB (NF-κB)/inhibitor κBα (IκB) transcription factor system plays an important role in regulating the biological responses of monocytes to pro-inflammatory mediators. Nuclear translocation of NF-κB is preceded by the proteolytic degradation of IκBα, an ankyrin motif-rich inhibitor that traps NF-κB in the cytoplasm. In addition, formation of cytoplasmic NF-κB/IκBα complexes in quiescent cells requires constitutive proteolytic processing of p105, another ankyrin motif-rich inhibitory protein from which the p50 subunit of NF-κB is generated. We have demonstrated that, following stimulation of human monocytic cells with lipopolysaccharide or tumor necrosis factor-α, this critical p105 processing event is up-regulated in concert with the inactivation of IκBα. Moreover, the degradative loss of both p105 and IκBα is prevented in cells depleted of intracellular ATP. In activated monocytes, however, IκBα degradation occurs more rapidly than p105 processing to p50. Together these findings provide direct biochemical evidence that p105 and IκBα are differentially sensitive targets for inducible proteolysis via ATP-dependent degradative pathways.
Antigenic Drift and Efficacy of Influenza Virus Vaccines, 1976–1977

A unique opportunity occurred in February 1977 to assess the efficacy of an influenza virus vaccine given to military personnel in doses of 400 chick cell-agglutinating (CCA) units of A/Victoria/3/75, 400 CCA units of A/New Jersey/76, and 500 CCA units of B/Hong Kong/72 viruses. After cessation of all influenza virus vaccine administration in mid-December 1976, approximately 200 unvaccinated U.S. Air Force personnel arrived per week beginning February 1, 1977, at Lowry Air Force Base, Denver, Colorado. Arriving unvaccinated personnel were assigned to one of 12 units with previously vaccinated personnel. A sharp outbreak of influenza A occurred on the base during February that was due to an A/Texas/1/77-like virus, a variant of the A/Victoria/3/75 prototpye. Fifty-four cases of influenza A were documented in the student population on the base. During the two-week peak of the outbreak, attack rates were 10-fold higher in unvaccinated than in vaccinated students, and the overall estimate of vaccine efficacy was 80%. Thus, despite animal tests suggesting considerable antigenic drift, a vaccine containing influenza A/Victoria/3/75 virus provided good protection against the variant strain.
Hydration in hyaluronic acid and its esters using differential scanning calorimetry

Abstract Differential scanning calorimetry (DSC) was used to distinguish three types of water of hydration in sodium hyaluronate and ethyl, benzyl, and partial benzyl esters of hyaluronic acid. These three types were defined as follows: type I: free, freezing water (freezing temperature ≈ 0 ° C); type II: weakly bound, freezing water (freezing temperature
Topical hesperidin enhances epidermal function in an aged murine model.

Author(s): Man, George; Mauro, Theodora M; Zhai, Yongjiao; Kim, Peggy L; Cheung, Carolyn; Hupe, Melanie; Crumrine, Debbie; Elias, Peter M; Man, Mao-Qiang
The increase in hexokinase activity in heredityry avian muscular dystrophy

Abstract Hexokinase activity was found to be increased in both the more severely affected white (pectoral) and less severely affected red (thigh) muscle of dystrophic chickens. The increase in activity was largely associated with the particulate fraction. These findings may indicate early events in the pathogenesis of avian muscular dystrophy.
Anchoring molecular chromophores to colloidal gold nanocrystals: surface-enhanced Raman evidence for strong electronic coupling and irreversible structural locking.

High-affinity anchoring groups such as isothiocyanate (ITC, —N═C═S) are often used to attach organic chromophores (reporter molecules) to colloidal gold nanocrystals for surface-enhanced Raman scattering (SERS), to atomically smooth gold surfaces for tip-enhanced Raman scattering, and to scanning tunneling microscopy probes (nanosized electrodes) for single-molecule conductance measurements. However, it is still unclear how the attached molecules interact electronically with the underlying surface, and how the anchoring group might affect the electronic and optical properties of such nanoscale systems. Here we report systematic surface-enhanced Raman studies of two organic chromophores, malachite green (MG) and its ITC derivative (MGITC), that have very different functional groups for surface binding but nearly identical spectroscopic properties. A surprise finding is that, under the same experimental conditions, the SERS signal intensities for MGITC are nearly 500-fold higher than those of MG. Correcting...
Cardiovascular and blood coagulative effects of pulmonary zinc exposure.

Abstract Cardiovascular damage induced by pulmonary exposure to environmental chemicals can result from direct action or, secondarily from pulmonary injury. We have developed a rat model of pulmonary exposure to zinc to demonstrate cardiac, coagulative, and fibrinolytic alterations. Male Wistar Kyoto rats were instilled intratracheally with saline or zinc sulfate, 131 μg/kg (2 μmol/kg); the alterations were determined at 1, 4, 24, and 48 h postexposure. High-dose zinc enabled us to show changes in circulating levels of zinc above normal and induce significant pulmonary inflammation/injury such that cardiac impairments were likely. At 1–24 h postexposure, plasma levels of zinc increased to nearly 20% above the base line. Significant pulmonary inflammation and injury were determined by analysis of bronchoalveolar lavage fluid and histopathology in zinc-exposed rats at all time points. Starting at 4 h postexposure, pulmonary damage was accompanied by persistently increased gene expressions of tissue factor (TF) and plasminogen activator-inhibitor-1 (PAI-1), but not thrombomodulin (TM). Cardiac tissues demonstrated similar temporal increases in expressions of TF, PAI-1, and TM mRNA following pulmonary instillation of zinc. In contrast to extensive pulmonary edema and inflammation, only mild, and focal acute, myocardial lesions developed in a few zinc-exposed rats; no histological evidence showed increased deposition of fibrin or disappearance of troponin. At 24 and 48 h postexposure to zinc, increases occurred in levels of systemic fibrinogen and the activated partial thromboplastin time. These data suggest that cardiovascular blood coagulation impairments are likely following pulmonary zinc exposure and associated pulmonary injury and inflammation.
Almost automorphic solutions to some classes of partial evolution equations

We give in this work some sufficient conditions for the existence and uniqueness of almost automorphic (mild) solutions to some classes of partial evolution equations. Then we use our abstract results to discuss the existence and uniqueness of almost automorphic solutions to some partial differential equations.
Scanning confocal microscope for precise measurement of optical fiber diameter

We have constructed and evaluated a scanning confocal microscope for the precise measurement of optical fiber cladding diameter. The system measures the fiber endface directly and differs from conventional microscopes in that there is no systematic error due to partial coherence. The results obtained with the scanning confocal microscope are checked by comparison with those obtained from a contact micrometer and by measuring a chrome-on- glass standard reference material provided by NIST, Gaithersburg, Maryland. Fiber diameters can be measured with a random uncertainty of 40 nm and a systematic error estimated to be 40 nm.© (1992) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.