cssi/SciSciGPT-SciSciNet huggingface dataset:
Resilience in Long-Term Viral Infection: Genetic Determinants and Interactions.

Virus-induced neurological sequelae resulting from infection by Theiler’s murine encephalomyelitis virus (TMEV) are used for studying human conditions ranging from epileptic seizures to demyelinating disease. Mouse strains are typically considered susceptible or resistant to TMEV infection based on viral persistence and extreme phenotypes, such as demyelination. We have identified a broader spectrum of phenotypic outcomes by infecting strains of the genetically diverse Collaborative Cross (CC) mouse resource. We evaluated the chronic-infection gene expression profiles of hippocampi and thoracic spinal cords for 19 CC strains in relation to phenotypic severity and TMEV persistence. Strains were clustered based on similar phenotypic profiles and TMEV levels at 90 days post-infection, and we categorized distinct TMEV response profiles. The three most common profiles included “resistant” and “susceptible,” as before, as well as a “resilient” TMEV response group which experienced both TMEV persistence and mild neurological phenotypes even at 90 days post-infection. Each profile had a distinct gene expression signature, allowing the identification of pathways and networks specific to each TMEV response group. CC founder haplotypes for genes involved in these pathways/networks revealed candidate response-specific alleles. These alleles demonstrated pleiotropy and epigenetic (miRNA) regulation in long-term TMEV infection, with particular relevance for resilient mouse strains.
Diversity and stability of restriction enzyme profiles of plasmid DNA from methicillin-resistant Staphylococcus aureus.

Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a significant epidemiological problem. Detecting the sources of epidemic strains and preventing their access to patients, however, depend upon the availability of techniques to reliably distinguish among MRSA strains. We evaluated restriction enzyme analysis of plasmid DNA for use as an epidemiological marker of MRSA strains. The diversity of plasmid types was assessed by examining 120 clinical and environmental MRSA isolates from five southern California hospitals and from the American Type Culture Collection. Thirty-seven distinctive EcoRI digestion patterns were observed. We characterized each strain by the number of plasmids it contained and the sizes of the fragments that were generated by EcoRI. Very few of the isolates (4.2%) lacked plasmids, and some (6.7%) contained DNA that was not digested by EcoRI. Several isolates (12.5%) contained two or more plasmids. We were able to assess the stability of MRSA plasmid types by tracking epidemic strains over a 2-year period. We also examined successive isolates from 10 individual patients during their hospitalization. In all but one case, the patient9s plasmid profiles remained unchanged. We conclude that the diversity and stability of MRSA plasmid types make them excellent epidemiological markers. In support of this conclusion, we found that our data provided significant epidemiological insights. Two epidemic strains, accounting for more than half of the infections, were identified in the five hospitals. The remaining cases were sporadic, caused by MRSA strains that appeared very infrequently and that may have originated from sources outside the hospitals. Images
Using Interconnection Style Rules to Infer Software Architecture Relations

Software design techniques emphasize the use of abstractions to help developers deal with the complexity of constructing large and complex systems. These abstractions can also be used to guide program- mers through a variety of maintenance, reengineering and enhancement activities. Unfortunately, recovering design abstractions directly from a system's implementation is a difficult task because the source code does not contain them. In this paper we describe an automatic process to in- fer architectural-level abstractions from the source code. The first step uses software clustering to aggregate the system's modules into abstract containers called subsystems. The second step takes the output of the clustering process, and infers architectural-level relations based on formal style rules that are specified visually. This two step process has been im- plemented using a set of integrated tools that employ search techniques to locate good solutions to both the clustering and the relationship in- ferencing problem quickly. The paper concludes with a case study to demonstrate the effectiveness of our process and tools.
The Unsolved Problem of Star Formation: Dusty Dense Cores and the Origin of Stellar Masses

The development of a predictive theory of star formation is one of the prime goals of modern astrophysics. The problem of star formation is a very complex one and its solution depends critically on empirical data. In this contribution, I review some of the progress that has been achieved in identifying and measuring the fundamental boundary and initial conditions that constrain the solution and must be met by any complete theory of star formation. In particular, I discuss what is known about the stellar IMF and the nature of dense cores on the verge of star formation. I then discuss how these two topics contribute to our general understanding of the origin of stellar mass, the key mystery in the star formation process.
Soliton solutions of coupled Maxwell–Bloch equations

Abstract In this paper we study the soliton solutions of the coupled Maxwell–Bloch equations which describe pulse propagation in an active optical medium with coherent three-level atomic transitions and inhomogeneous broadening. The soliton solutions and polarization shifts due to soliton interactions are investigated. An infinite set of conservation laws as well as the soliton trace formulae are derived.
One antenna, two antennae, big antennae, small: total antennae length, not bilateral symmetry, predicts odor-tracking performance in the American cockroach Periplaneta americana.

Determining the location of a particular stimulus is often crucial to an animal9s survival. One way to determine the local distribution of odor is to make simultaneous comparisons across multiple sensors. If the sensors detect differences in the distribution of odor in space, the animal can then steer toward the source. American cockroaches, Periplaneta americana , have 4 cm long antennae and are thought to track odor plumes using a spatial sampling strategy, comparing the amount of odor detected between these bilateral sensors. However, it is not uncommon for cockroaches to lose parts of their antennae and still track a wind-borne odor to its source. We examined whether bilateral odor input is necessary to locate an odor source in a wind-driven environment and how the loss of increasing lengths of the antennae affects odor tracking. The tracking performances of individuals with two bilaterally-symmetrical antennae of decreasing length were compared to antennal length-matched individuals with one antenna. Cockroaches with one antenna were generally able to track an odor plume to its source. In fact, the performances of unilaterally antennectomized individuals were statistically identical to their bilaterally symmetrical counterparts when the total length of both antennae equaled the length of the single antenna of the antennectomized individuals. This suggests that the total length of available antennae influences odor tracking performance more than any specific piece of antenna, and that they may be doing something more complex than a simple bilateral comparison between their antennae. The possibility of an antenna-topic map is discussed.
Adaptation to host plants may prevent rapid insect responses to climate change

We must consider the role of multitrophic interactions when examining species' responses to climate change. Many plant species, particularly trees, are limited in their ability to shift their geographic ranges quickly under climate change. Consequently, for herbivorous insects, geographic mosaics of host plant specialization could prohibit range shifts and adaptation when insects become separated from suitable host plants. In this study, we examined larval growth and survival of an oak specialist butterfly (Erynnis propertius) on different oaks (Quercus spp.) that occur across its range to determine if individuals can switch host plants if they move into new areas under climate change. Individuals from Oregon and northern California, USA that feed on Q. garryana and Q. kelloggii in the field experienced increased mortality on Q. agrifolia, a southern species with low nutrient content. In contrast, populations from southern California that normally feed on Q. agrifolia performed well on Q. agrifolia and Q. garryana and poorly on the northern, high elevation Q. kelloggii. Therefore, colonization of southern E. propertius in higher elevations and some northern locales may be prohibited under climate change but latitudinal shifts to Q. garryana may be possible. Where shifts are precluded due to maladaptation to hosts, populations may not accrue warm-adapted genotypes. Our study suggests that, when interacting species experience asynchronous range shifts, historical local adaptation may preclude populations from colonizing new locales under climate change.
The Structure of Chromosomes

honey or glue, long curling threads extending out from the broken ends. The cytoplasm is more liquid (stage i). In a day or two, however, the cytoplasm has usually attained the consistency of a firm jelly or of cheese, while the chromosomes are still harder (stage 2). In this state the cell contents may be squeezed flat by carefully graduated pressure, without injury to the chromosomes. In the course of time the hardening
Photoadaptation to the polar night by phytoplankton in a permanently ice-covered Antarctic lake

Photosynthetic microorganisms are a primary source of new organic carbon production in polar ecosystems. Despite their importance, relatively little is known about how they adapt to the bimodal solar cycles that exist at high latitudes. To understand how phytoplankton adapt to the extreme seasonal change in photoperiod, we transplanted cultures of a well-studied laboratory model for photosynthetic cold adaptation, Chlamydomonas raudensis UWO241, back to the water column of Lake Bonney (McMurdo Dry Valleys, Antarctica) at the depth from which it was originally cultured. The organism was suspended at this depth in dialysis tubing to allow the microalga to respond to the in situ light, temperature and dissolved ions. We then integrated in situ biological and chemical measurements with environmental molecular analyses and compared the responses of transplanted C. raudensis cultures with the natural phytoplankton community over the 6-week transition from Antarctic summer (24-h daylight) to polar night (24-h darkness). As solar radiation declined, natural communities exhibited a cessation of inorganic carbon fixation which was accompanied by a downregulation of expression of genes encoding for essential carbon fixation and photochemistry proteins. Transplanted C. raudensis cultures matched natural community trends in the regulation of photochemistry and carbon fixation gene expression, and shifted photochemical function to a shade adapted state in response to the polar night transition. We present a conceptual model for seasonal shifts in microbial community energy and carbon acquisition which integrates past cultivation-based studies in this model photopsychrophile with a body of recent work on adaptation of natural populations to polar night.
EFFECT OF SORBIC ACID AND SODIUM NITRITE ON Clostridium botulinum OUTGROWTH AND TOXIN PRODUCTION IN CANNED COMMINUTED PORK

Experiments to determine the effect of sorbic acid alone and in combination with low nitrite and phosphate on botulinal toxin production in inoculated perishable, canned, comminuted, cured pork were conducted. Forty-eight test lots of product were inoculated with approximately 100 spores per gram of five strains each of type A and B Clostridium botulinum. Twenty-five cans of each test lot were incubated at 27° C for up to 110 days. The time of swelling was recorded for each can and the first 10 swells per test lot were tested for toxin. Multiple regression analysis of the time to first swell showed nitrite concentration had a significant linear effect on delaying outgrowth and toxin production of C. botulinum. Sorbic acid concentration was also significantly related to inhibition but through the fourth power of sorbic acid concentration. The use of either sodium acid pyrophosphate or sodium hexametaphosphate was synergistic with sorbic acid as indicated by their statistically significant positive interactions. Several test lots containing 0.2% sorbic acid and either phosphate had no toxic swells after 110 days of incubation with or without 50 ppm NaNO2. These data indicate that sorbic acid may be a potential alternative preservative to high levels of nitrite in canned, comminuted pork products.
Gas chromatographic determination of β-phenethylbiguanide and its metabolite p-hydroxy-β-phenethylbiguanide in serum and urine

A gas chromatographic method is presented for the detection of β-phenethylbiguanide (PEBG) and its metabolite, p-hydroxy-β-phenethylbiguanide (p-OH PEBG). The procedure is applicable for the determination of the drug and its metabolite in the serum and urine of rats. The detection limit is 0.2 μg PEBG and 0.5 μg p-OH PEBG per ml of serum or urine. A time course study of blood concentration and elimination rate following intraperitoneal injection of 100 mg/kg of PEBG to normal rats was performed. β-PEBG was found to be present in the blood and the urine, p-OH PEBG was only detected in the urine. Twenty-four hours following intraperitoneal injection, the urine contained 32% of the administered dose, 20% as unaltered PEBG and 12% as p-OH PEBG.
Frequency and nature of specific-locus mutations induced in female mice by radiations and chemicals: a review

Abstract The inducibility of heritable mutations in female mammals has been measured in the mouse specific-locus test (SLT). For radiation-induced mutations, a large body of data has been accumulated that includes information about biological and physical factors that influence mutation yields. However, relatively few SLT studies in females have been conducted with chemicals to date. A single estimate of the spontanous mutation rate in oocytes, 6 536,207 , has been derived as the most appropriate one to subtract from experimental rates. This rate is highly significantly below the spontaneous mutation rate in males. Mutations recovered from females mutagenized at any time after about the 12th day post-conception are induced in non-dividing cells. In adult females, most oocytes are arrested in small follicles; maturation from this stage to ovulation takes several weeks. High-dose-rate radiations are more mutagenic in mature and maturing oocytes than in spermatogonia of the male; on the other hand, no clearly induced mutations have been recovered from irradiated arrested oocytes. Efficient repair processes have been invoked to explain the latter finding as well as the upward-curving dose-effect relation for acute irradiation, and the fact that dose protraction drastically reduces mutation yield from mature and maturing oocytes. The dose-protraction effect is much greater than that found in spermatogonia. Radiation-induced mutation rates in embryonic, fetal, and newborn females are overall lower than those in the mature and maturing oocytes of adults. A dose-protraction effect has also been demonstrated at an early developmental stage when the nuclear morphology of mouse oocytes most resembles that of the human. Of only 5 chemicals so far explored for their effect in oocytes, 2 (ethylnitrosourea, ENU, and triethylenemelamine, TEM), and possibly a third (procarbazine hydrochloride, PRC), are mutagenic — with at least one of these (ENU) mutagenic in arrested as well as maturing oocytes. However, the mutation rate is, in each case, lower than for treated male germ cells. By contrast, ENU-induced mutation yield for the maternal genome of the zygote is an order of magnitude higher than that for the zygote's paternal genome or for spermatogonia. A high proportion of mutants derived from chemical treatment of oocytes (including the oocyte genome in zygotes) are mosaics, probably owing to lesions affecting only 1 strand of the DNA. A characteristic of specific-locus mutations induced in oocytes is that they include a considerably higher percentage of large (multi-locus) lesions (LLs) than do mutations induced in spermatogonia. For each germ-cell type, the frequency of LLs appears lower for the chemicals so far tested than for radiations.
The Distribution of Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF) and its Receptor (GM-CSF-R) in the Developing Human Fetus ♦ 255

The Distribution of Granulocyte Macrophage-Colony Stimulating Factor (GM-CSF) and its Receptor (GM-CSF-R) in the Developing Human Fetus ♦ 255
It helps to be well connected

Parasites are everywhere. Yet despite this ubiquity, they are not in all places at all times. For a particular host-parasite pairing, infections vary greatly over space and time, with some but not all host populations suffering infections in a given year. What drives this variation? This question is important not just because parasites can have major ecological and evolutionary impacts, but also because disease outbreaks can have devastating impacts in agricultural systems and on species of conservation concern ( 1 , 2 ). On page 1289 of this issue, Jousimo et al. ( 3 ) investigate how being highly connected to other populations affects the likelihood of a Plantago population being colonized by a fungal pathogen.
Feeding Levels for Fish Fed Formulated Diets

Abstract A simple feeding formula, percent body weight of food to give = 2 x °C/(100k x L), is offered the fish culturist; k is condition factor and L is fish length. The formula is based on the Buterbaugh-Willoughby hatchery constant, but the shortcomings of that method (i.e., how to deal with variable water temperatures and condition factors) are overcome. As with all feeding formulas and tables, this formula serves merely as a guideline. Use of this formula provides a rapid, practical tool to evaluate the efficiency of an ongoing feeding program. It can be applied when only water temperature, fish length, and condition factor are known.
Step-and-scan and step-and-repeat: a technology comparison

While the semiconductor manufacturing community is preparing for the transition from 0.35micrometers to 0.25micrometers technology, lithography equipment suppliers are preparing for the shift from step-and-repeat to step-and-scan systems. In addition, most wafer stepper users are planning to change from i-line to KrF laser wavelength technology. The question, however, is what are the advantages and disadvantages of scanners over steppers in a production environment. In this paper, we discuss the two different technologies using the following criteria: (1) throughput/cost of ownership, (2) CD control/depth of focus, (3) distortion and overlay. 248 nm lithography will be used for the 0.25micrometers process rule regime in combination with i-line systems being used for 50 to 70 percent of the lithography steps to reduce cost. Therefore, an ideal match is required between i-line systems and their DUV critical layer counterparts. For this reason, the economic equation of step-and-scan is determined by the total picture of matched DUV and i-line scanners. However, the comparisons between non-laser-based scanners and steppers and laser-based scanners and steppers are different. This paper discusses this subject using a combination of theoretical modeling and measured data. Imaging data from a new, DUV, double telecentric, 0.4 to 0.57 variable NA wafer stepper equipped with a variable coherence/annular illuminator is shown; thus proving that good imaging data at 0.25micrometers resolution at moderate cost is possible using wafer steppers.
Glucocorticoids act together with estrogens and thyroid hormones in regulating the synthesis and secretion of Xenopus vitellogenin, serum albumin, and fibrinogen

In Xenopus serum albumin and fibrinogen are proteins whose synthesis and secretion by the liver are regulated by dexamethasone, while the synthesis and secretion of vitellogenin are regulated by estradiol-17β. We have previously demonstrated (Wangh and Schneider, 1982, Develop. Biol. 89, 287–293) that triiodothyronine acts together with estradiol-17β in the induction of vitellogenin in liver cultures. We report here on the interactions of dexamethasone with estradiol-17β and triiodothyronine. When pieces of liver from an in vivo estrogen-induced animal were maintained in culture for more than 2 weeks in a defined hormone-free medium, synthesis of secreted proteins gradually decreased. Addition of estradiol-17β, even at 10−6M, reinduced very little secreted vitellogenin. In agreement with our earlier finding, addition of triiodothyronine together with estradiol-17β reinduced very high levels of secreted vitellogenin. Dexamethasone at a minimum effective dose of 10−8M reinduced secreted albumin and fibrinogen. If triiodothyronine was also added, the dose of dexamethasone required was 10−9M. Thus, triiodothyronine enhances the activity of either single steroid. Addition of dexamethasone together with estradiol-17β resulted in reinduction of vitellogenin as well as serum albumin and fibrinogen. Unexpectedly, addition of dexamethasone together with estradiol-17β and triiodothyronine resulted in reinduction of vitellogenin, but the failure to induce serum albumin and fibrinogen. It is known from in vivo studies that extensive treatment with estradiol-17β induces high levels of vitellogenin synthesis, but suppresses liver synthesis of most other secreted proteins, including serum albumin and fibrinogen. Thus, we have demonstrated that estrogen suppression of glucocorticoid regulated secreted proteins also occurs in isolated pieces of liver tissue and that suppression requires all three of the tested hormones.
Investigatory behavior of a novel conspecific by Wistar Kyoto, Wistar and Sprague-Dawley rats.

The assumption was made that investigatory behaviors (i.e., ano-genital and general body sniffing) of a female conspecific by a mature male rat, has positive hedonic characteristics. Because reduced interest in pleasurable events (i.e., anhedonia) is diagnostically related to depressive behavior, the hypothesis was advanced that less investigatory behavior would be observed in an animal model of depression, namely the Wistar Kyoto (WKY) rat strain. In Experiment 1, WKY, Wistar and Sprague-Dawley male rats were subjected, in the first test series, to three consecutive 2-min exposures to one intruder stimulus female, followed later by another three consecutive 2-min exposures to a second stimulus intruder female. On the second test series, 24 h later, the male rats were exposed to one female for 2 min, followed 6 min later to another 2-min exposure to another stimulus female. Half the male subjects were subjected to tail shock stress 2 h before the first test series. All males demonstrated a habituation of the investigatory response to the same stimulus female, but a dishabituation when subsequently exposed to a new stimulus female. Only WKY rats, exposed to prior stress, revealed a significant reduction in investigatory behavior. In Experiment 2, using only WKY and Wistar rats, a factorial design was used to observe any differences between two stressors, namely tail shock and water restraint, and also to observe possible differences in investigatory behavior towards male vs. female intruder rats. Restraint stress and shock stress elicited significant reductions in investigatory behavior for WKY rats, but not Wistar rats, when confronted with female intruder rats. Male intruders elicited more freezing behavior, as well as aggressive defensive fighting behavior from resident male rats. The results are interpreted to suggest that the significant decrease in investigatory behavior towards a female intruder, which was observed primarily in stressed WKY males, reflects the presence of anhedonia in stressed WKY rats, and reinforces our assertion that the WKY rat strain represents a useful animal model of depressive behavior.
First-principles modeling of boron clustering in silicon

We present results of ab initio calculations for the structure and energetics of boron–interstitial clusters in Si and a respective continuum model for the nucleation, growth, and dissolution of such clusters. The structure of the clusters and their possible relationship to boron precipitates and interstitial-cluster formation are discussed. Our continuum model suggests that inclusion of the fractional activation of charged clusters into the overall carrier count can make a substantial differ
Numerical models for diagenesis and the Neogene Sr isotopic evolution of seawater from DSDP Site 590B

Abstract A numerical model for the diagenetic exchange of Sr between carbonates and their pore fluids during sedimentation and compaction has been developed. The model has been applied to data from DSDP Site 590B in order to assess the accuracy with which the Sr isotope record in the carbonate sediment reflects that of seawater. The most important process affecting the Sr in the solid carbonate is exchange with the pore fluid due to solution-reprecipitation, but the concentration or isotopic composition of Sr in the solid itself gives little or no information as to the magnitude of this exchange. The key to determining the rate of exchange is the pore fluid, where the variations of Sr2+ and87Sr/86Sr with depth are very sensitive indicators. The logical structure of applying the model to data from DSDP 590B is to find by successive iteration an ocean history (i.e., the initial87Sr/86Sr and Sr concentration of each increment of carbonate deposited) and a rate of Sr exchange between pore water and solid carbonate such that the model matches the present Sr concentration and87Sr/86Sr of both pore water and solid carbonate. Once all the data are matched, the model provides an estimate of the rate of Sr exchange due to solution-reprecipitation and the evolution of87Sr/86Sr in seawater over the past 20 million years. For DSDP 590B we find that solution-reprecipitation decreases rapidly with depth, from a near surface value of about 10% per million years to about 1% per million years below 200 m. This rate of exchange of Sr results in the carbonates of DSDP 590B preserving an accurate record of the Sr isotopic evolution of the ocean over the past 5 million years, but for ages greater than 5 million years the87Sr/86Sr ratio of the carbonate is systematically displaced from that of the seawater in which it was deposited. The maximum difference is of order 5 × 10−5.
Baseline optical coherence tomography predicts the development of glaucomatous change in glaucoma suspects.

Purpose To assess whether baseline retinal nerve fiber layer (RNFL) measurements obtained with optical coherence tomography (OCT2; Carl Zeiss Meditec, Dublin, California, USA) are predictive of the development of glaucomatous change. Design Cohort study. Methods Participants were recruited from the University of California, San Diego (UCSD) longitudinal Diagnostic Innovations in Glaucoma Study (DIGS). One eye was studied from each of 114 glaucoma suspects with normal standard automated perimetry (SAP) and OCT RNFL imaging at baseline. The cohort was divided into two groups based on the development of glaucomatous change (repeatable abnormal visual fields and/or a change in the stereophotographic appearance of the optic disk). Cox proportional hazards models were used to determine the predictive ability of OCT RNFL thickness measurements. Results Over a 4.2-year average follow-up period, 23 eyes (20%) developed glaucomatous changes and 91 (80%) did not. At baseline, thinner RNFL measurements, higher SAP pattern standard deviation (PSD), “glaucoma” stereophotograph assessment, and thinner central corneal thickness (CCT) were associated with the study endpoints in univariate analysis. After adjusting for age, intraocular pressure (IOP), CCT, and PSD in multivariate models, a 10 μm thinner average, superior and inferior RNFL at baseline was predictive of glaucomatous change [hazard ratio (95% CI); 1.51 (1.11 to 2.12), 1.57 (1.17 to 2.18), and 1.49, (1.19 to 1.91), respectively]. Results were consistent when stereophotographic assessment was included in multivariate analysis. Conclusions Thinner OCT RNFL measurements at baseline were associated with development of glaucomatous change in glaucoma suspect eyes. RNFL thinning was an independent predictor of the glaucomatous change, even when adjusting for stereophotograph assessment, age, IOP, CCT, and PSD.
A fast table lookup based, statistical model driven non-uniform unit selection TTS

For multi-channel TTS applications, e.g. in a cloud service, it is highly desirable that high quality speech can be synthesized in low complexity. In this paper, we propose a fast table lookup based, statistical model driven approach to non-uniform unit selection TTS for that purpose. In TTS training, the voice font of all waveform segments is organized as a Gaussian kernel coded hash table and a table for storing quantized costs of all possible concatenation segment pairs. In synthesis, waveform segments with non-uniform lengths are first selected to construct a candidate lattice by looking up the Gaussian kernel coded hash table, and the best path is searched in the lattice by minimizing the accumulated concatenation scores, which are retrieved from the quantization table for possible concatenations. Experimental results show that the new approach can significantly reduce the search complexity while keep a high TTS voice quality.
Sex and the patient with cardiovascular risk factors: focus on sildenafil

Erectile dysfunction (ED) is common in men with cardiovascular disease. The introduction of sildenafil citrate, the first oral agent for the treatment of this disorder, has increased awareness about the risks of sexual activity in cardiac patients and raised concerns about the safety of sildenafil in patients being treated for coronary disease. Sildenafil is a potent and selective inhibitor of phosphodiesterase type 5 (PDE5), the enzyme responsible for the degradation of cyclic guanosine monophosphate (cGMP). Sildenafil acts along the same general pathway as nitric oxide donors to increase cGMP levels and enhance erections. Sildenafil is a modest vasodilator that causes small decreases in systemic arterial pressure and mild preload and afterload reductions. It does not cause major decreases in blood pressure when administered with one or more standard antihypertensive agents. Because PDE5 is also present in small amounts in the systemic vasculature, sildenafil can cause a synergistic and major decrease in pressure when combined with organic nitrates. Use of organic nitrates is the only contraindication to sildenafil use. Data on sildenafil in patients with recent (less than 6 months) myocardial infarction (MI), unstable angina, stroke, and recent life-threatening arrhythmias are not available, so the drug should be used with caution in patients with unstable cardiac conditions. Placebo-controlled and open-label phase 2/3 trials including men with ischemic heart disease did not show an increase in MI or serious cardiovascular events in patients treated with sildenafil versus placebo. None of the serious cardiovascular events reported in these trials were considered treatment related by the investigators. There is a small but finite increased risk of developing ischemia or infarction with sexual activity. Therefore, before prescribing sildenafil or any current or future treatment for ED to patients with known cardiac disease or multiple cardiovascular risk factors, physicians should discuss the potential cardiac risk of sexual activity and perform a complete medical assessment, including an exercise stress test if appropriate.
Evaluation of the Phoenix 100 ID/AST System and NID Panel for Identification of Enterobacteriaceae, Vibrionaceae, and Commonly Isolated Nonenteric Gram-Negative Bacilli

The Phoenix 100 ID/AST system (Becton Dickinson Co., Sparks, Md.) is an automated system for the identification and antimicrobial susceptibility testing of bacterial isolates. This system with its negative identification (NID) panel was evaluated for its accuracy in the identification of 507 isolates of the family Enterobacteriaceae, 57 other nonenteric gram-negative isolates that are commonly isolated in clinical microbiology laboratories, and 138 isolates of the family Vibrionaceae. All of the isolates had been characterized by using approximately 48 conventional tube biochemicals. Of the 507 isolates of the Enterobacteriaceae, 456 (89.9%) were correctly identified to the genus and species levels. The five isolates of Proteus penneri required an off-line indole test, as suggested by the system to differentiate them from Proteus vulgaris. The identifications of 20 (3.9%) isolates were correct to the genus level but incorrect at the species level. Two (0.4%) isolates were reported as "no identification." Misidentifications to the genus and species levels occurred for 29 (5.7%) isolates of the Enterobacteriaceae. These incorrect identifications were spread over 14 different genera. The most common error was the misidentification of Salmonella species. The shortest time for a correct identification was 2 h 8 min. The longest time was 12 h 27 min, for the identification of a Serratia marcescens isolate. Of the 57 isolates of nonenteric gram-negative bacilli (Acinetobacter, Aeromonas, Burkholderia, Plesiomonas, Pseudomonas, and Stenotrophomonas spp.), 48 (84.2%) were correctly identified to the genus and species levels and 7 (12.3%) were correctly identified to the genus level but not to the species level. The average time for a correct identification was 5 h 11 min. Of the Vibrionaceae spp., 123 (89.1%) were correctly identified at the end of the initial incubation period, which averaged 4 h. Based on the findings of this study, the Phoenix 100 ID/AST system NID panel falls short of being an acceptable new method for the identification of the Enterobacteriaceae, Vibrionaceae, and gram-negative nonenteric isolates that are commonly encountered in many hospital microbiology laboratories.
The Ewald-Oseen extinction theorem

When a beam of light enters a material medium, it sets in motion the resident electrons, whether these electrons are free or bound. The electronic oscillations in turn give rise to electromagnetic radiation which, in the case of linear media, possesses the frequency of the exciting beam. Because Maxwell's equations are linear, one expects the total field at any point in space to be the sum of the original (exciting) field and the radiation produced by all the oscillating electrons. However, in practice the original beam appears to be absent within the medium, as though it had been replaced by a different beam, one having a shorter wavelength and propagating in a different direction. The Ewald–Oseen theorem resolves this paradox by showing how the oscillating electrons conspire to produce a field that exactly cancels out the original beam everywhere inside the medium. The net field is indeed the sum of the incident beam and the radiated field of the oscillating electrons, but the latter field completely masks the former. Although the proof of the Ewald–Oseen theorem is fairly straightforward, it involves complicated integrations over dipolar fields in three-dimensional space, making it a brute-force drill in calculus and devoid of physical insight. It is possible, however, to prove the theorem using plane waves interacting with thin slabs of material, while invoking no physics beyond Fresnel's reflection coefficients. (These coefficients, which date back to 1823, predate Maxwell's equations.
Separating Octadecyltrimethoxysilane Hydrolysis and Condensation at the Air/Water Interface through Addition of Methyl Stearate.

The hydrolysis and condensation of octadecyltrimethoxysilane (OTMS) at the air/water interface were monitored through molecular area changes at a constant surface pressure of 10 mN/m. The onset of condensation was delayed through the addition of methyl stearate (SME) acting as an inert filler molecule. In the absence of SME, complete gelation of OTMS required 30 h, during which time OTMS condensation occurred concomitantly with hydrolysis. In the presence of SME, the OTMS monolayer gelation rate increased in proportion to the amount of SME present. A 1:6 OTMS:SME molar ratio resulted in monolayer gelation within 30 min, suggesting completion of monomer hydrolysis prior to condensation. These findings indicate that lability of OTMS to hydrolysis at the air/water interface is governed by steric and conformational constraints at the silicon atom site, with monomeric OTMS being much more reactive than oligomeric OTMS. Fluorescence microscope images demonstrated that the OTMS condensed domain size also decreased with increasing SME concentrations, further implicating SME’s role as an inert filler.
EQUILIBRIUM MODEL BASED ON A MICROFOUNDATION FOR FORECASTING DIAL-A-RIDE RIDERSHIP

The demand and capacity of a van dial-a-ride service for elderly and disabled passengers are analyzed together. The service demand is based on a survey of an advanced public transit system for an elderly and disabled persons van service. Demand is estimated by the Poisson regression on individual demand and by aggregating over individuals in the market. Service supply is modeled in two ways—a deterministic queuing model and a regression model—and is estimated by using drivers' manifest data. Market demand is compared with market supply derived from each method to identify the equilibrium level of ridership and travel time, which are used to measure the service quality. The model is used to predict a trade-off between ridership and travel time and to present this trade-off conveniently on a simple tabulation form. The service provider can use this form to determine combinations that maximize the management objective without engaging in simulation or estimation for all possible choices.
Experimental Retinectomy with a 6.1 μm Q-switched Raman-shifted Alexandrite Laser

Purpose: It is hypothesized that 6.1 μm produced by a portable laser would be useful for incising tissue layers such as performing a retinectomy in detached retina with extensive anterior proliferative vitreoretinopathy. Methods: An alexandrite laser system, which provides a high-intensity Q-switched pulse (780 nm, 50-100 ns duration, 10 Hz), is wavelength-shifted by a two-stage stimulated Raman conversion process into the 6-7 μm range (Light Age, Inc.). Fresh cadaver porcine retinas were lased with 6.1 μm using a 200 μm diameter spot at 0.6 mJ after removal of the vitreous. Specimens were examined grossly and prepared for histological examination. Results: The Raman-shifted alexandrite laser produced a smooth Gaussian profile. A narrow spectrum was produced at 6.1 μm. A full-thickness retinal incision with minimal thermal damage was obtained at a low energy level of 0.6 mJ in the retinas. However, the depth of the incision did vary from an incomplete incision to a full-thickness incision involving the underlying choroidal layer in attached retinas. Conclusions: The 6.1 μm mid-infrared energy produced by a portable laser is capable of incising detached retinas with minimal thermal damage.
Familial multiple endocrine neoplasia type 1 Mutation of a tumor suppressor gene

Familial multiple endocrine neoplasia type 1 (FMENI) is caused by mutation of a gene on the long arm of chromosome 11. Inactivation of both alleles at this locus in one cell is thought to cause loss of growth inhibition and development of a monoclonal tumor.
Optimum versus clinically established levels of continuous positive airway pressure in respiratory therapy

To evaluate the efficacy of our routine method of cardiopulmonary monitoring for accurate management of respiratory therapy, continuous positive airway pressure (CPAP) was titrated in 11 surgical intensive care patients within ±7.5 cm H2O of the clinically selected level. Cardiopulmonary data were independently and retrospectively reviewed by three experienced critical care physicians from three outside hospitals. Each physician estimated the optimum level of CPAP for each patient. Variability between reviewers was not statistically significant. The optimum CPAP level based on all reviewers' opinions (8.6±5.7 cm H2O, mean±SD) was significantly lower than that selected clinically (13.2±4.5 cm H2O;P<0.05). We conclude that current methodology for monitoring respiratory therapy is inefficient for rapid adjustment of CPAP to appropriate levels. Continuous arterial and pulmonary artery oximetry may provide an improvement in the efficacy of cardiopulmonary monitoring in the future.
What is the Moore method

ABSTRACT We describe a “Moore Method” course which we have taught at several universities over the past 30 years. Our course is a modification of one we took from R. L. Moore in 1948. The course is intended to be taken immediately after a one variable calculus course. The purpose of the course is to teach the students to create and present in class mathematically correct proofs of theorems. This, of course, requires training in logic and correct use of language. Our topics are the topology of the line and basic principles of the calculus, including limits, continuity, and differentiability. Our goal is to get the students to prove the fundamental theorem of calculus. We discuss our grading, class discussions, the ways in which we help students, and the extent to which we encourage cooperative learning.
Insulin resistance in the spontaneously hypertensive rat.

To determine experimentally if insulin resistance is associated with spontaneously occurring hypertension, insulin-stimulated glucose metabolism was studied in an animal model of genetic hypertension. The spontaneously hypertensive rat (SHR) and its genetic control, the Wistar-Kyoto strain (WKY)_were studied with the euglycemic hyperinsulinemic clamp technique. Clamp studies demonstrated reduced insulin-stimulated glucose uptake in SHR (P < .001). These data indicate that SHR is insulin-resistant when compared with WKY. A reduction of insulin-stimulated glucose metabolism occurred in older animals of both strains, providing evidence of an aging effect on insulin-stimulated glucose metabolism. However, the reduction of insulin-stimulated glucose metabolism was more pronounced in the hypertensive animals. This study demonstrates the presence of peripheral (skeletal muscle) insulin resistance in the SHR.
Estrogen-Stimulated Deoxyribonucleic Acid Synthesis: A Ratchet Model for the Prereplicative Period*

Multiple injections of a short acting estrogen, l,3,5(10)-estratriene-3,16α-diol (16α-E2), have been used to analyze the lag or prereplicative period of approximately 12 h, which precedes the onset of estrogen-stimulated DNA synthesis. A single injection of 1.0 μg 16α-E2, which itself does not stimulate DNA synthesis, shortened by 3–4 h the lag period between subsequently administered estrogen and the initiation of DNA synthesis. This lag-shortening effect of 16α-E2 was stable for 24 h, but had decayed by 36 h. One or two additional injections of 16α-E2 given sequentially at 3-h intervals each further shortened the lag period but to a lesser extent than the first injection. The results indicate that estrogen induces the accumulation of relatively stable cell changes which are required for the onset of DNA synthesis. The prolonged estrogen requirement during the lag period is not truly discontinuous as previously suggested but rather can be satisfied by discontinuous pulses of estrogen in a ratchet-like fa...
Attentional distribution in the visual field duringsame-different judgments as assessed by response competition

Judgments ofsame anddifferent on a comparison task have been found to be subject to response competition if an irrelevant stimulus is presented in the display along with the target stimuli. For example, the reaction time for judging two letters the same is markedly increased if a different but irrelevant letter is also present in the display (C. W. Eriksen, O’Hara, & B. [A.] Eriksen, 1982). We have made use of this competition effect to map the visual attentional field in two dimensions. In two experiments, we varied the size of the attended area by varying the separation of the comparison stimuli. The boundaries of the attended area were mapped by varying the location of a response-competitive irrelevant noise letter. On this task, the attended area was found to be elliptical in shape, with the location of the target stimuli defining the major axis. The minor axis of the ellipse increased in direct proportion to increases in the major axis. Rather than interpret these field effects in terms of areas of enhanced processing, we propose that instead they represent the limits or failures in inhibition of competing stimulation.
IDENTIFYING NODES AND ANTI-NODES OF AN AXIALLY VIBRATING BAR WITH LUMPED MASS

By attaching a lumped virtual mass to a complicated structure and tracking the maxima and local minima of the frequency curves of the assembled system, one can locate the nodes and anti-nodes of the (original) complicated structure
Intraoral ulcers of questionable origin

The need for a frank, thoroughly complete history from the patient to aid in diagnosing intraoral ulcerations is discussed. Intraoral ulcerations may be elicited by numerous causative factors or aggravated by a host of other conditions, the diagnoses of which can plague the general dental practitioner as well as the specialist. This case is an example whereby all the diagnostic aids and tools were useless without a frank and thoroughly complete history from the patient.
Evaluation of integrals for a ten-node isoparametric tetrahedral finite element

Abstract The use of isoparametric finite elemts in solving three-dimensional problems typically requires the numerical evaluation of a large number of integrals over individual element domains. The evaluation of these integrals by numerical quadrature, which is the traditional approach, can be computationally expensive. For certain problems the present study provides a more efficient method for evaluation of the needed integrals. For these problems some or all of the desired integrals can be evaluated as linear combinations of basic integrals whose integrands are either (i) products of shape (interpolation) functions or (ii) a derivative of a shape function times a product of one or more shape functions. Basic integrals of these two types (when written in terms of local coordinate systems) have integrands which are polynomial both in the variables of integration and in the nodal coordinates and, thus, can be expressed as linear combinations (with rational number coefficients) of a set of polynomial functions of the nodal coordinates. Group theoretic techniques can be employed to select appropriate sets of polynomial functions for use in these expansions and to reduce substantially the number of basic integrals which need to be explicitly evaluated. The details for the approach have been worked out for a ten-node isoparametric tetrahedral element through the use of MACSYMA, a computer system for algebraic manipulation. The symmetry group for this element has order 24. The basic integrals of types (i) and (ii) are expressed as linear combinations of 20 and 26 terms, respectively. The special case of a straight-edged tetrahedral element with mid-edge nodes is also discussed.