cssi/SciSciGPT-SciSciNet huggingface dataset:
Purification and characterization of a new xylanase (APX-II) from the fungus Aureobasidium pullulans Y-2311-1.

Aureobasidium pullulans Y-2311-1 produced four major xylanases (EC 3.2.1.8) with pI values of 4.0, 7.3, 7.9, and 9.4 as revealed by isoelectric focusing and zymogram analysis when grown for 4 days on 1.0% oat spelt xylan. The enzyme with a pI of 9.4 was purified by ammonium sulfate precipitation, chromatography on a DEAE-Sephadex A-50 column, and gel filtration with a Sephadex G-75 column. The enzyme had a mass of about 25 kDa as determined by both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography. The purified enzyme had a Km of 7.6 mg . ml(-1) and Vmax of 2,650 micromol . min(-1) . mg(-1) for birchwood xylan at 28 degrees C and pH 4.5. It lacked activity towards carboxymethylcellulose, cellobiose, starch, mannan, p-nitrophenyl (pNP)-beta-D-xylopyranoside, pNP-beta-D-glucopyranoside, pNP-alpha-D-glucopyranoside, pNP-beta-D-cellobioside, pNP-beta-D-fucopyranoside, or pNP-alpha-D-galactopyranoside. The predominant end products of birchwood xylan or xylohexaose hydrolysis were xylobiose and xylose. The enzyme had the highest activity of pH 4.8 and 54 degrees C. Sixty percent of the activity remained after the enzyme had been incubated at 55 degrees C and pH 4.5 for 30 min. The sequence of the first 68 amino acid residues at the amino terminus showed homology to those of several other xylonases. Immunoblot analysis with antiserum raised against the purified xylanase revealed that two immunologically related polypeptides of 25 and 22 kDa were produced in A. pullulans cultures containing oat spelt xylan or xylose as carbon sources but not in cultures containing glycerol or glucose.
The management of preterm labor

Preterm birth is the leading cause of neonatal mortality and a substantial portion of all birth-related short- and long-term morbidity. Spontaneous preterm labor is responsible for more than half of preterm births. Its management is the topic of this review. Although there are many maternal characteristics associated with preterm birth, the etiology in most cases is not clear, although, for the earliest cases, the role of intrauterine infection is assuming greater importance. Most efforts to prevent preterm labor have not proven to be effective, and equally frustrating, most efforts at arresting preterm labor once started have failed. The most important components of management, therefore, are aimed at preventing neonatal complications through the use of corticosteroids and antibiotics to prevent group B streptococcal neonatal sepsis, and avoiding traumatic deliveries. Delivery in a medical center with an experienced resuscitation team and the availability of a newborn intensive care unit will ensure the best possible neonatal outcomes. Obstetric practices for which there is little evidence of effectiveness in preventing or treating preterm labor include the following: bed rest, hydration, sedation, home uterine activity monitoring, oral terbutaline after successful intravenous tocolysis, and tocolysis without the concomitant use of corticosteroids.
Computer-determined kinetic parameters from TG curves. Part IX

Abstract By applying the restriction that α (conversion) = constant to non-isothermal TG (NITG), isothermal TG (ITG) and a combination of both (NITG/ITG), various corresponding expressions have been derived for the evaluation of the activation energy, E . By means of a computer, all the expressions developed were tested against data which was generated from theoretical equations. Also, changes were made in the number of significant figures (s.f.) of data in order to ascertain their effects on values of E . Data were generated and tested for the three theoretical mechanisms, A 2 , F 1 and R 2 .
Efficient dynamic Monte Carlo algorithm for time-dependent catalytic surface chemistry

Several numerical algorithms for dynamic Monte Carlo simulations of surface chemistry have been proposed in the past. The variable step size method (VSSM) is commonly used for systems where the rate coefficients are constant in time, owing to its good efficiency. If rate coefficients vary in time, the first reaction method (FRM) has been shown to be more efficient. However, the cost of this algorithm to execute a reaction step depends on the considered lattice size, which can make this method inefficient for systems involving surface phenomena on different scales. Here we propose a general and efficient algorithm, the fast first reaction method (fFRM), which has the advantages of being applicable to systems with constant and time-varying rate coefficients, and of having a computational cost per reaction step that is independent of the lattice size. An additional feature of fFRM is that it is rejection-free, which means that once a reaction class is selected, a reaction of that type will be executed. A rejection-free variant of VSSM, called rVSSM, is also presented, which leads to an approximately 15% speedup compared with the VSSM algorithm for the considered example.
Gifted Children in a Hurried Society; Implications of Elkind's Theories

This article is a reflection of the author's concern for gifted children in America's “hurried society” and was based on the book, The Hurried Child by David Elkind. The areas of school, media and parents and peers are examined for their “hurried effects” on gifted children.
Bare spot: a normal variant on shoulder MR arthrography.

A 14-year-old boy with shoulder pain after a football injury underwent shoulder MR arthrography. The study revealed a focal area of cartilage thinning (Fig. 1 arrow) at the central area of the glenoid, simulating a cartilage defect. The sagittal image showed a focal contrast-filled area at the central portion of the glenoid (Fig. 2 arrow). This cartilage thinning at the central area of the glenoid represents a bare spot. No abnormality was identified to account for the child’s pain.
Biological Bottom-Up Assembly of Antibody Nanotubes on Patterned Antigen Arrays

Application of biotechnology in nanofabrication has an advantage to produce functional building-block materials that may not have synthetic counterparts. Here we introduced a new type of building block, antibody nanotubes, and demonstrated anchoring them on complementary antigen arrays via antibody-antigen recognition. Biological recognition between the antibody nanotubes and the antigen arrays permitted recognition-driven assembly of ordered nanotube arrays. The array of antigens was written by using the tip of an atomic force microscope (AFM) on alkylthiol self-assembled monolayer (SAM)-coated Au substrates via nanografting. After antigens were immobilized onto the shaved regions of the alkylthiol SAMs with the AFM tip, antibody nanotubes, produced by incubating antibodies in template nanotube solutions, were selectively attached onto the antigen regions. This technique is very useful when multiple building blocks are necessary to address specific locations on substrates because simultaneous immobilization of multiple antibody nanotubes at specific complementary binding positions can be achieved in a single process.
Proteolysis and developmental signal transduction.

Abstract Regulated proteolysis is a critical feature of many intercellular signalling pathways that control cell-fate specification and tissue patterning during metazoan development. The roles of proteolysis in three different pathways, the Toll, Hedgehog, and Notch pathways, are described to illustrate the importance of specific protein cleavages in both extracellular ligand–receptor interactions and intracellular signal transduction. An emerging principle is the use of proteolysis to control the maturation and activation of receptors, to limit the spatial diffusion of their ligands, and to modulate the subcellular localization or transcriptional activity of DNA-binding factors in response to receptor–ligand interactions at the cell surface.
Business Communication Skills in Information Systems (IS) Curricula: Perspectives of IS Educators and Students

As the importance of communication skills for students, regardless of their disciplines, becomes evident, it is important to determine whether colleges provide students with adequate opportunities to acquire such skills. The authors compared information systems (IS) educator and student perceptions of communication skills in IS curricula. Gender, discipline, position and student classification, and school size were among the variables that were examined. Results showed that educators and students agreed that IS curricula had the appropriate emphasis on many of the communication skills. However, the two groups significantly differed on their extent of agreement or disagreement with appropriate level of emphasis and the number of courses that cover such communication skills. Results revealed that educators felt there were a few communication skills, such as proofreading, listening, facilitating meetings, and using interpersonal skills with external customers and management, that needed more emphasis in the ...
Perinatal and socioeconomic risk factors for variable and persistent cognitive delay at 24 and 48 months of age in a national sample.

The objective of this paper is to examine patterns of cognitive delay at 24 and 48 months and quantify the effects of perinatal and sociodemographic risk factors on persistent and variable cognitive delay. Using data from 7,200 children in the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), multiple logistic regression models identified significant predictors of low cognitive functioning at 24 and 48 months. Additional multiple logistic models predicting cognitive delay at 48 months were estimated separately for children with and without delay at 24 months. Of the nearly 1,000 children delayed at 24 months, 24.2% remained delayed by 48 months; 7.9% of the children not delayed at 24 months exhibited delay at 48 months. Low and very low birthweight increased cognitive delay risk at 24, but not 48 months. Low maternal education had a strongly increasing effect (OR = 2.3 at 24 months, OR = 13.7 at 48 months), as did low family income (OR = 1.4 at 24 months, OR = 7.0 at 48 months). Among children delayed at 24 months, low maternal education predicted delay even more strongly at 48 months (OR = 30.5). Low cognitive functioning is highly dynamic from 24 to 48 months. Although gestational factors including low birthweight increase children’s risk of cognitive delay at 24 months, low maternal education and family income are more prevalent in the pediatric population and are much stronger predictors of both persistent and emerging delay between ages 24 and 48 months.
Effects of image compression and degradation on an automatic diabetic retinopathy screening algorithm

Diabetic retinopathy (DR) is one of the leading causes of blindness among adult Americans. Automatic methods for detection of the disease have been developed in recent years, most of them addressing the segmentation of bright and red lesions. In this paper we present an automatic DR screening system that does approach the problem through the segmentation of features. The algorithm determines non-diseased retinal images from those with pathology based on textural features obtained using multiscale Amplitude Modulation-Frequency Modulation (AM-FM) decompositions. The decomposition is represented as features that are the inputs to a classifier. The algorithm achieves 0.88 area under the ROC curve (AROC) for a set of 280 images from the MESSIDOR database. The algorithm is then used to analyze the effects of image compression and degradation, which will be present in most actual clinical or screening environments. Results show that the algorithm is insensitive to illumination variations, but high rates of compression and large blurring effects degrade its performance.
Modeling Short-Term Interest Rate Volatility: Information Shocks versus Interest Rate Levels

This article investigates the impact of information shocks and interest rate levels on the volatility of six national short-term interest rates. Short-term rates are assumed to follow a single-factor diffusion process that tests several popular models that have been used in literature. The elasticity of variance with respect to the level of interest rates is not as important as reported by some researchers. In fact, models using only information shocks perform better than models using only levels. In all cases, however, the best volatility specification requires the use of both information shocks and interest rate levels. Mean reversion does not appear to be an important feature of short-term interest rates.
Verifying policy-based web services security

WS-SecurityPolicy is a declarative language for configuring web services security mechanisms. We describe a formal semantics for WS-SecurityPolicy and propose a more abstract language for specifying secure links between web services and their clients. We present the architecture and implementation of tools that (1) compile policy files from link specifications, and (2) verify by invoking a theorem prover whether a set of policy files run by any number of senders and receivers correctly implements the goals of a link specification, in spite of active attackers. Policy-driven web services implementations are prone to the usual subtle vulnerabilities associated with cryptographic protocols; our tools help prevent such vulnerabilities. We can verify policies when first compiled from link specifications, and also re-verify policies against their original goals after any modifications during deployment. Moreover, we present general security theorems for all configurations that rely on compiled policies.
Detection and classification of organophosphate nerve agent simulants using support vector machines with multiarray sensors.

The need for rapid and accurate detection systems is expanding and the utilization of cross-reactive sensor arrays to detect chemical warfare agents in conjunction with novel computational techniques may prove to be a potential solution to this challenge. We have investigated the detection, prediction, and classification of various organophosphate (OP) nerve agent simulants using sensor arrays with a novel learning scheme known as support vector machines (SVMs). The OPs tested include parathion, malathion, dichlorvos, trichlorfon, paraoxon, and diazinon. A new data reduction software program was written in MATLAB V. 6.1 to extract steady-state and kinetic data from the sensor arrays. The program also creates training sets by mixing and randomly sorting any combination of data categories into both positive and negative cases. The resulting signals were fed into SVM software for “pairwise” and “one” vs all classification. Experimental results for this new paradigm show a significant increase in classificati...
Monocarboxylate Transporters are not Responsible for Cr 3+ Transport from Endosomes

Cr3+, similar to Fe3+, is transported into cells primarily via endocytosis as the metal-transferrin complex. As Cr3+ ions are not readily reduced under biological conditions, the ion cannot be transported from endosomes by the same mechanism as iron that utilized divalent metal ion transporters. Cr3+ has been hypothesized to potentially be transported as small ligand complexes with a free carboxylate functionality by monocarboxylate transporters (MCT), in a similar fashion to that proposed for Al3+. Consequently, mouse C2C12 muscle cells were utilized to determine if Cr3+ is potentially transported by MCT by examining the effects of MCT inhibitors on Cr and Fe transport and subcellular distribution when the metals are added as their transferrin complexes. The results suggest that Cr is not primarily transported by MCT from the endosomes to the cytosol, and that another mechanism for this transport needs to be identified.
Stilbestrols and stilbestrol derivatives: estrogenic potency and temporal relationships between estrogen receptor binding and uterine growth.

This study analyzes some of the differences between the estrogenic potencies of two homo logous stilbestrols, the potent estiogen diethylstilbestrol (DES) and the weak estrogen dimethylstilbestrol (DMS). The action of these compounds and their corresponding dimethyl ethers is compared in terms of the duration of their interaction with the estrogen receptor in immature rat uterus and the time-course of responses elicited in this tissue. Dose-response curves of 3-day uterotrophic assays indicate that etherification of DMS, which is only weakly uterotrophic, converts it into a compound, DMS-(OMe)2, that has enhanced uterotrophic activity, while etherification of the more active estrogen, DES, diminishes its potency. Only at high doses is DES-(OMe)2 as effective a uterotrophic agent as DES. After a single injection, DMS (20 μg) and DES (10 μg) both rapidly translocate estrogen receptor from the cytoplasmic to the nuclear compartment, but while uterine weight (by 24 h) and nuclear receptor levels (by 6 h) rapidly return to control levels after DMS, they remain elevated for a more prolonged period after DES. Likewise, DMS stimulates only an early (2 h) wave of uterine deoxyglucose phosphorylation. In contrast to DMS, DMS-(OMe)2 (20 μg) shows a gradual movement of receptor to the nucleus after 1 h, with moderate but above control levels of receptor being maintained for at least 36–48 h. This retention of nuclear receptor correlates with prolonged elevation of uterine weight (beyond 60 h) and stimulation of deoxyglucose metabolism (beyond 24 h). Likewise a high (10 μg) dose of DES-(OMe)2 evokes a slower but more protracted elevation of nuclear receptor levels, and a more prolonged elevation of uterine weight than does DES (10 μg). The weak activity of DMS appears to be due to its short duration of interaction with receptor, and conversion to the methyl ether prolongs nuclear receptor occupancy and increases its biological potency. DES is potent because it is itself long-acting. Methylation of DES further extends its period of nuclear receptor occupancy; this increases its duration of action at high doses, but reduces its potency at low doses.
Management of head and neck burns.

Treatment of burn injuries of the head and neck can be divided into acute and chronic stages. The acute phase consists of physiologic resuscitation of the patient and early care of the burn wound. The chronic stage begins from completion of wound coverage until the wound has matured. A major advance in the care of the patient with head and neck burns has been the realization that clinical application of exercise, traction, and pressure can reduce the development of contractures and hypertrophic scarring. Once the burn scars mature, the residual scar deformity can be improved by reconstructive surgical procedures.
New glucagon analogues with conformational restrictions and altered amphiphilicity: Effects on binding, adenylate cyclase and glycogenolytic activities

In an effort to obtain highly potent glucagon antagonists, we have investigated glucagon (1) structure-function relationships utilizing the following design principles: (1) structural changes known to lead to partial agonist activities; (2) conformational restrictions; (3) changes in the conformational probabilities of the primary sequence; and (4) increased amphiphilicity. In this report we present the total synthesis, purification, receptor binding, adenylate cyclase activity, in vivo glycogenolytic activity and CD spectrum of the following four glucagon analogues: [Ahx17,18]glucagon (2), [D-Phe4,Tyr5, 3,5-diiodo-Tyr10,Arg12,Lys17,18,Glu21]glucagon (3), [Asp9,Lys12,Lys17,18,Glu21]glucagon 4, and [Glu15,Lys17,18]glucagon 5. Compound 2 binds exclusively to the high affinity receptor and compound 3 was a highly potent antagonist with respect to adenylate cyclase activity. Analog 4 showed distinct biphasic binding (IC50 5.6 nM and 630 nM), with only the low affinity binding leading to adenylate cyclase activity. Furthermore in analogue 5 receptor binding and adenylate cyclase activity were dissociated by a factor of 5. The results are consistent with a multistep binding mechanism in which glucagon interacts first nonspecifically with the anisotropic interphase of the cell membrane, followed by a conformational transition which occurs in the sequences 10-14 and 15-18 when the membrane bound peptide binds to its receptor.
TDDB-based performance variation of combinational logic in deeply scaled CMOS technology

As CMOS technology is scaled down, the gate oxide is scaling aggressively. The defects in the gate oxide form traps over time and results in gate oxide break down. Time-dependent dielectric breakdown (TDDB) is considered as one of the most important reasons of performance variation of CMOS devices. Soft break down events do not cause immediate failure of the CMOS device but will affect the performance of the circuit, especially for future CMOS applications which are more susceptible to soft break down events. However, the reasons for delay variation (increase or decrease) after TDDB are not clear for researchers. In this paper, detail analysis and simulation results for the delay variation of digital circuit due to TDDB are demonstrated for different locations and levels using 32nm CMOS technology. In this paper, we show that the circuit delay can be increased or decreased depending on the input rising or falling transition of the circuit as well as the number of consecutive gates which are affected by TDDB.
EFFECTS OF BLANCHING METHOD ON THE QUALITY CHARACTERISTICS OF FROZEN PEAS

This study evaluated the effects of microwave blanching prior to freezing as an alternative pretreatment for frozen peas. Peas were blanched (steam-, boiling water immersion-, microwave- or microwave-blanched in a bag), frozen and evaluated after 0, 6 and 12 weeks for moisture and ascorbic acid content, peroxidase activity, visual appearance and instrumental color, and after 6 and 12 weeks for aroma, flavor and texture. All blanch treatments reduced peroxidase activity by 97% compared with controls (unblanched); blanching methods did not differ. Steam blanching resulted in significantly better ascorbic acid retention than all other treatments; microwave blanch treatments were either equivalent to or better than boiling water immersion. Both microwave treatments darkened (L* value) peas. Microwave-blanched peas were visually greener than other treatments, but their appearance was less intact. Aroma and flavor were similar among blanch treatments. Texture of boiling water immersed peas was similar to the two microwave treatments.
Myocardial Discontinuities A Substrate for Producing Virtual Electrodes That Directly Excite the Myocardium by Shocks

Background —Theoretical models suggest that an electrical stimulus causes regions of depolarization and hyperpolarization on either side of a myocardial discontinuity. This study determined experimentally whether an artificial discontinuity gives rise to an activation front in response to an electrical stimulus, consistent with the creation of such polarized regions. Methods and Results —After a thoracotomy in six dogs, a 504-unipolar-electrode plaque was sutured to the right ventricular epicardium to map activations. From a line electrode parallel to one side of the plaque, 10 S 1 stimuli were delivered, followed by S 2 and S 3 stimuli (S 1 S 1 , S 1 S 2 , S 2 S 3 interval=300 ms). S 1 and S 3 stimuli were 25 mA; 5-ms S 2 stimuli of both polarities were initially 25 mA and increased in 25 mA increments. The plaque was removed, and a transmural incision was made through the ventricular wall in the middle of the mapped region and sutured closed. The plaque was replaced and the stimulation protocol repeated. Before the incision, S 2 stimuli directly activated tissue only near the stimulation site. An activation front arose at the border of the directly activated region and propagated across the plaque. As the S 2 stimulus strength was increased, the size of the directly activated region increased. After the incision, sufficiently large S 2 stimuli caused direct activation of tissue adjacent to the transmural incision as well as at the stimulation site. Activation fronts that arose adjacent to the transmural incision either propagated proximally toward the stimulation site and collided with the activation front originating from the stimulation wire or propagated distally away from the incision. Minimum S 2 stimulus strengths activating areas adjacent to the incision were only 45±14% (cathode) and 39±18% (anode) of the strengths required to directly activate the same area before the incision was formed ( P Conclusions —Myocardial discontinuities can give rise to activation fronts after a stimulus, suggesting the presence of polarized regions adjacent to the discontinuity.
EXPRESSION OF INDOLEAMINE 2,3-DIOXYGENASE IN THE RHESUS MONKEY AND COMMON MARMOSET

Indoleamine 2,3-dioxygenase (IDO) catalyzes the initial and rate-limiting step of tryptophan degradation along the kynurenine pathway, and is hypothesized to limit tryptophan availability at embryo implantation and prevent maternal T cell activation at the maternal-fetal interface. To determine if nonhuman primates are suitable models for investigating the role of IDO during pregnancy, we defined the expression of IDO in the rhesus monkey and common marmoset with particular attention to the female reproductive tract and placenta. IDO mRNA was detected by RT-PCR in the rhesus monkey term placenta, lung, small intestine, spleen, lymph node and nonpregnant uterus, and also in the common marmoset placenta. Immunohistochemical analysis of rhesus monkey tissues localized IDO to glandular epithelium of nonpregnant endometrium and first trimester decidua, vessel endothelium of nonpregnant myometrium, first trimester decidua and term decidua, and villous vessel endothelium and syncytiotrophoblast of term placenta. Western blot analysis confirmed IDO in rhesus monkey term placenta. In the common marmoset, IDO was detected in glandular epithelium of the nonpregnant uterus and in the decidua at day 60 and day 128 of gestation. IDO activity was higher in rhesus monkey and common marmoset decidua and placentas than in other tissues. Confirmation of IDO expression in rhesus monkey and common marmoset uterine and placental tissues supports the hypothesis that this enzyme regulates immune activation at the maternal-fetal interface and demonstrates that nonhuman primates may provide models with distinct similarities to human placentation to study the role of IDO in maternal-fetal immune dialogue.
Histologic follow‐up of nondiagnostic thyroid fine needle aspirations: Implications for adequacy criteria

There is limited histologic follow-up for adequacy criteria in thyroid fine needle aspirations. We correlated the number of benign follicular cells in nondiagnostic aspirates (excluding atypical and Hurthle cells) and the results of histologic follow-up. A total of 170 cases with only benign follicular cells were reviewed. The sensitivity and specificity for 60 benign follicular cells was 97% and 42%. If the threshold for adequacy was lowered to 10 cells, the specificity of a benign diagnosis increased significantly (42% to 50%, P < 0.001) without a significant change in sensitivity (97% to 96%, P = 0.45). An additional 63 cases were diagnosed as adequate with three false negative cases. Lowering the threshold to 30 cells had no change in sensitivity (97%), increased specificity to 45% but this was not significant (P = 0.08). An additional 26 aspirates could be diagnosed as adequate without any false negative cases. Histologic follow-up suggests that the current criteria for adequacy can be lowered to improve specificity while retaining excellent sensitivity.
Reproductive performance of Bracon hebator females following acute exposure to sulphur dioxide in air

Abstract Bracon hebetor females were exposed to 3 ppm SO 2 for 3 h and 5 h and their reproductive performance was assayed for 20 days. Lifespan of the treated females and their egg production were not different from those of control wasps. Also, egg hatchability, an important indicator of fertility, was not consistently affected. These results indicate Bracon reproductive performance, a sensitive toxicological assay system, to be resistant to acute SO 2 exposure. Putative SO 2 effects on parasitic wasp populations in nature are therefore probably not due to interference with female fecundity and fertility.
Effects of electrical brainstem stimulation on tinnitus.

The primary aim of the auditory brainstem implant (ABI), an investigational device, is to restore auditory sensations in neurofibromatosis-2 patients deafened by bilateral acoustic neuroma surgery. An electrode is placed on the dorsal cochlear nucleus after the tumor is removed through the translabyrinthine approach. This procedure was performed on 18 patients: 13 were completely deafferentated after bilateral tumor removal and had received the ABI during surgery on the second-sided tumor; 5 were implanted at first-sided tumor removal. Three of these 5 patients had usable hearing remaining on the side of the second acoustic neuroma and were stimulated only during laboratory sessions. All patients had tinnitus. We used a questionnaire to assess the effects of brainstem stimulation on this symptom. Of the 18 patients, one early patient deceased, and one patient with no follow-up was not included in this study. Six patients who were unable to use the ABI because of temporary hardware problems or side effects...
Lifestyle Characteristics during Medical School: A Four-Year Cross-Sectional Study

Sammary.-A comgrehensive questionnaire on lifestyle was completed by 58 of 184 freshmen, 104 of 181 sophomores, 108 of 183 juniors, and 40 of 183 seniors about midway through the fall semester. Generally, seniors exercised most frequently, slept more hours per night, consumed fewer drinks containing caffeine, wore scat belts a higher percentage of the time, and had a greater number of friends they felt close to than did other students. The level of stress was rated higher by preclinical students. Freshmen spent fewer hours on recreational activities. Generally, the freshmen enjoyed medical school more, found medical school to be more challenging, and felt more competent as medical students than did the other students. Over-all, the frequency of dental and medical checkups decreased from the freshman to the senior year. Medical educators and students have voiced discontent with the current state of medical education, and far-reaching reforms in the teaching of medical students have been advocated (Bok, 1984). Medical students are young adults who deal with the developmental task of intimacy versus isolation (Erikson, 1980), and the stresses of the medical school environment may interfere with the attainment of this and other developmental tasks (Pfeiffer, 1983). Generalized stresses, stresses differentiating the basic science and clinical years, and stresses unique to each year have been identified (Bok, 1984; Pfeiffer, 1983; Gaensbauer & Mizner, 1980; Keniston, 1967). During the first year, students must determine their capability in a new context and achieve a level of performance commensurate with that capability. Self-imposed limits on the amount of material to be learned must be met. Beginning students must also reassess personal and social involvements. The issue of commiunent is of paramount importance during the second year, during which students are fearful of developing whatever disorder is being discussed in class. Consolidation of the srudent's identity is prominent during the third year by virtue of involvement in intense clinical work. Coping with death and helplessness develops as do difficulties that may arise from interacting with other medical personnel. The fourth year is viewed as the least stressful because, although the clinical work continues, there is more time for electives. It may be problematic for students who have a poor tolerance for loss (Pfeiffer, 1983; Gaensbauer & Mizner, 1980). Over-all, medical students must come to grips with striking a proper bal
Invigorating cancer prevention: proposing core competencies in cancer prevention research training.

Successes in cancer prevention research over the past 60 years have altered clinical care and had broad implications for public health. Notable examples include the development of chemopreventive agents (e.g., tamoxifen reducing breast cancer risk), vaccines against infectious agents known to cause cancer (hepatitis B and human papillomavirus), screening and early detection targeting groups at higher risk (colonoscopy for ages 50 and older), and recommendations for lifestyle modifications, some of which have also been accompanied by policy efforts (smoking cessation programs and bans on smoking in public places).[1, 2] Yet despite these laudable advances, there is a pervasive sense among both the public and those in the field that “we should be further along in preventing cancer.” This rigorous science and decades of work required for discoveries to be translated into public health practice seem to be largely under-recognized by both the public and scientific community. When advances in cancer research are highlighted, prevention of cancer rarely takes center stage. Even in this time when emphasis is placed on finding higher quality, lower cost health interventions in general, the word ‘prevention’ may not even be mentioned.1 This state of affairs has led us to contemplate whether a new view of cancer prevention research training is necessary to energize this field and accelerate progress in preventing cancer.
CdSe Clusters: At the Interface of Small Molecules and Quantum Dots

We have prepared and isolated a variety of cadmium selenide cluster molecules by the reaction of Cd(O2C–R)2(H2NR′)2 (R = C4H9, 4-X-Ph; X = H, −OMe, −SMe, −Me, −F, and −CF3; R′ = dodecyl, phenethyl) with tri-n-octylphosphine selenide (TOPSe) and diphenylphosphine selenide (DPPSe). Reactions conducted with 1.0 equiv of DPPSe lead to a cluster with a lowest energy electronic transition at 418 nm (d ≈ 1.5 nm, e(418 nm) = 189 000 ± 27 000 M–1 cm–1) and a broad (fwhm = 0.75 eV) and intense white light emission profile (ΦPL = 0.11(03)). Nuclear magnetic resonance spectroscopy, Rutherford backscattering spectrometry and solution molecular weight determinations support a molecular formula of [(CdSe)4(Cd(O2C–C6H5)2)(H2NC12H25)2]7(±1). Mechanistic studies indicate that 2 equiv of DPPSe convert to [Se2PPh2]−[H3NR′]+ and diphenyl phosphine upon mixing with H2NR′ and prior to reaction with cadmium benzoate. Reactions with TOPSe result in a series of CdSe nanocrystals characterized by discrete steps in size with absorpt...
Pathogen and host genotype differently affect pathogen fitness through their effects on different life-history stages

Adaptation of pathogens to their hosts depends critically on factors affecting pathogen reproductive rate. While pathogen reproduction is the end result of an intricate interaction between host and pathogen, the relative contributions of host and pathogen genotype to variation in pathogen life history within the host are not well understood. Untangling these contributions allows us to identify traits with sufficient genetic variation for selection to act and to identify mechanisms of coevolution between pathogens and their hosts. We investigated the effects of pathogen and host genotype on three life-history components of pathogen fitness; infection efficiency, latent period, and sporulation capacity, in the oat crown rust fungus, Puccinia coronata f.sp. avenae, as it infects oats (Avena sativa). We show that both pathogen and host genotype significantly affect total spore production but do so through their effects on different life-history stages. Pathogen genotype has the strongest effect on the early stage of infection efficiency, while host genotype most strongly affects the later life-history stages of latent period and sporulation capacity. In addition, host genotype affected the relationship between pathogen density and the later life-history traits of latent period and sporulation capacity. We did not find evidence of pathogen-by-host genotypic (GxG) interactions. Our results illustrate mechanisms by which variation in host populations will affect the evolution of pathogen life history. Results show that different pathogen life-history stages have the potential to respond differently to selection by host or pathogen genotype and suggest mechanisms of antagonistic coevolution. Pathogen populations may adapt to host genotypes through increased infection efficiency while their plant hosts may adapt by limiting the later stages of pathogen growth and spore production within the host.
Epigenetic repeat-induced gene silencing (RIGS) in Arabidopsis.

In several plant systems expression of structurally intact genes may be silenced epigenetically when a transgenic construct increases the copy number of DNA sequences. Here we report epigenetic silencing inArabidopsis lines containing transgenic inserts of defined genetic structure, all at the same genomic locus. These comprise an allelic series that includes a single copy of the primary insert, which carries repeated drug resistance transgenes, and a set of its derivatives, which as a result of recombination within the insert carry different numbers and alleles of resistance genes. Although the drug resistance genes remained intact, both the primary and some recombinant lines nevertheless segregated many progeny that were partly or fully drug-sensitive because of silencing. As in other systems silencing was reversible, and correlated with decreased steady-state mRNA and increased DNA methylation. Each different number and combination of genes, on the same or different (i.e., homologous) chromosomes, conditioned its own idiosyncratic segregation pattern. Strikingly, lines with a single gene segregated only a few slightly drug-sensitive progeny whereas multi-gene lines segregated many highly sensitive progeny, indicating dependence of silencing at this locus on repeated sequences. This argues strongly against explanations based on antisense RNA, but is consistent with explanations based on ectopic DNA pairing. One possibility is that silencing reflects the interaction of paired homologous DNA with flanking heterologous DNA, which induces condensation of chromatin into a non-transcribable state.
A two-component mechanistic approach for the comminution of material that exhibits heterogeneous breakage characteristics

Abstract A two-component treatment is proposed, developed, and demonstrated for extending the mechanistic approach for comminution processes to particulates that exhibit heterogeneous breakage characteristics. It essentially consists of considering that the material is composed of two individual components. Each component may have different breakage parameters, but they are constant within each component. Application of the method to a high volatile bituminous coal ground in a Hardgrove Grindability Machine and to a hematite iron ore ground in a laboratory ball mill indicates greatly improved accuracy for the comminution of particulates that exhibit these characteristics.
N-(3,5-Dichlorophenyl)succinimide nephrotoxicity in the Fischer-344 rat

Abstract The nephrotoxic potential of N -(3,5-dichlorophenyl)succinimide (NDPS) was examined, in male Fischer-344 rats. Rats were administered NDPS (0.1, 0.2, 0.4 or 1.0 mmol/kg intraperitoneally (i.p.) or sesame oil (2.5 ml/kg, i.p.), and renal function was monitored at 24 and 48 h. NDPS (0.1 mmol/kg) stimulated organic ion uptake at 48 h. NDPS (0.2 mmol/kg produced diuresis but did not alter blood urea nitrogen (BUN), kidney weight or organic ion uptake by renal cortical slices at 48 h. High-dose NDPS (0.4 and 1.0 mmol/kg) administration produced diuresis, decreased accumulation of p -aminohippurate (PAH) and tetraethylammonium (TEA), increased BUN and kidney weight and caused acute tubular necrosis. At 24 h, NDPS (0.2 mmol/kg) decreased uptake of PAH and TEA and tended to increase BUN. These results are similar to previous reports of NDPS-induced nephrotoxicity in Sprague-Dawley rats and suggest that either rat model would be suitable for future studies on the mechanism(s) of NDPS-induced nephropathy.
Effects of layer design on the performance of InAs/AlSb/GaSb resonant interband tunneling diodes on GaAs substrates

The room temperature current-voltage characteristics of InAs/AlSb/GaSb resonant interband tunneling diodes (RITDs), grown by chemical beam epitaxy on GaAs substrates, are reported as a function of the InAs buffer layer thickness and different interface configurations. The peak-to-valley current ratio (PVCR) improved from 1 to 12 as the buffer thickness was increased from 0 to 500 nm and the density of dislocations caused by the lattice mismatch of ∼7% decreased. No significant improvement was seen for a buffer thickness beyond 500 nm. Dislocation-free RITDs, grown lattice-matched on InAs substrates, show PVCRs of approximately 16. The InAs/AlSb Interfaces in these structures can be either InSb-like or AlAs-like and the interface can have a very strong effect on the diode performance. Unlike the case in InAs/AlSb field effect transistor structures, an AlAs-like interface results in better PVCRs in the diodes. Details of the results of this study are presented.
Mission statement: militarized discourses in women's advocacy organizations

This article contributes to the literature on the role of advocacy groups in political processes by exploring militarism within women's advocacy organizations. Specifically, I bring together theories of banal nationalism and banal militarization to inform my analysis of pervasive militarized discourse in 13 women's advocacy groups in the state of Pennsylvania, USA. Discursive analysis of organizational websites and in-depth interviews with organizational leaders reveals that the use of militarized discourse is commonplace among state-level women's advocacy groups. I ultimately argue that advocacy groups' use of militarized discourse is inherently problematic as it reinforces hegemonic privilege and detracts from progressive organizing. I also account for the role that discourse plays in the creation of place/space (and vice versa) in my discussion of how Pennsylvania's unique political culture affects advocacy for women's rights. Grounded in feminist geopolitical work, I offer some potential solutions to ...
A Methodology for Trading-Off Performance and Robustness Under Uncertainty

Mathematical optimization plays an important role in engineering design, leading to greatly improved performance. Deterministic optimization however, may result in undesired choices because it neglects uncertainty. Reliability-based design optimization (RBDO) and robust design can improve optimization by considering uncertainty. This paper proposes an efficient design optimization method under uncertainty, which simultaneously considers reliability and robustness. A mean performance is traded-off against robustness for a given reliability level of all performance targets. This results in a probabilistic multi-objective optimization problem. Variation is expressed in terms of a percentile difference, which is efficiently computed using the Advanced Mean Value (AMV) method. A preference aggregation method converts the multi-objective problem to a single-objective problem, which is then solved using an RBDO approach. Indifference points are used to select the best solution without calculating the entire Pareto frontier. Examples illustrate the concepts and demonstrate their applicability.Copyright © 2005 by ASME
Fatty acid synthase: a metabolic oncogene in prostate cancer?

In 1920, Warburg suggested that tumors consistently rely on anaerobic pathways to convert glucose to ATP even in the presence of abundant oxygen (Warberg, 1956) despite the fact that it is less efficient for energy supply than aerobic glycolysis. The reasons for this remain obscure to date. More often than not, the microenvironment of solid tumors contains regions of poor oxygenation and high acidity. In this context hypoxia can act in an epigenetic fashion, inducing changes in gene expression and in metabolism for survival. It is reasonable to assume that only the tumor cells capable of developing an unusual tolerance to limiting oxygen availability and to the acidosis resulting from excessive lactate production, can survive. In addition to the striking changes that occur in glucose metabolism, studies in human cancer patients suggest that there is often also an increase in free fatty acid turnover, oxidation and clearance (Legaspi et al., 1987; Hyltander et al., 1991). For instance, a lipid mobilizing factor produced by tumor cells appears to be responsible for the increase in whole body fatty acid oxidation (Russell and Tisdale, 2002). Fatty acids synthesis in tumor tissues also occurs at very high rates, as first demonstrated more than half a century ago (Medes et al., 1953). Importantly, 14 C glucose studies have shown that in tumor cells almost all fatty acids derive from de novo synthesis despite adequate nutritional supply (Sabine and Abraham, 1967; Ookhtens et al., 1984; Weiss et al., 1986). In addition, tumors overexpressing fatty acid synthase (FAS), the enzyme responsible for de novo synthesis of fatty acids, display aggressive biologic behavior compared to those tumors with normal FAS levels, suggesting that FAS overexpression confers a selective growth advantage. Here, we will review the roles that FAS plays in important cellular processes such as apoptosis and proliferation. In addition, speculations on the putative role of FAS in the altered metabolic pathways of prostate cancer cells will be explored. Because of the frequent overexpression of this enzyme prostate cancer, FAS constitutes a therapeutic target in this disease.
Helmet-mounted display for the night attack mission

The U.S. Army's AH64 Apache helicopter performance during the Panama invasion and Desert Storm has silenced years of skeptical speculation regarding the utility of a visually coupled helmet-mounted display (HMD) in combat. Unfortunately, in the fixed wing community, pilot night vision is limited to viewing a I-HiD for FLIR imagery or image intensification (12) from a helmet mounted goggle. Presently, restricted visual freedom and high head/neck ejection safety risks are accepted penalties for operating at night. Full visual freedom during night missions is a feature not yet afforded to any U.S. military fighter aircraft. This paper will focus specifically on a candidate HMD system for the night attack mission. Included are trade-off discussions relative to several specific design decisions.
Penta-hepta defect motion in hexagonal patterns.

The structure and dynamics of penta-hepta defects (PHD`s) in hexagonal patterns are studied in the framework of coupled amplitude equations for the underlying plane waves. An analytical solution for the phase field of moving PHD is found in the far field, which generalizes the static solution due to Pismen and Nepomnyashchy. The mobility tensor of the PHD is calculated using a combined analytical and numerical approach. The results for the velocity of a PHD climbing in slightly nonoptimal hexagonal patterns are compared with numerical simulations of amplitude equations. The interaction of penta-hepta defects in optimal hexagonal patterns is considered.