cssi/SciSciGPT-SciSciNet huggingface dataset:
Ethical Issues in the Prenatal Diagnosis of Phenylketonuria

Clinicians often view ethical dilemmas in terms of individual patients: would couple X, who have a normal 2-year-old child with phenylketonuria (PKU) (due to early treatment), want prenatal diagnosis with subsequent pregnancies? Eventually, the question will be posed on that level, but not yet. At this stage, we are still dealing with a new, unproven technology; a more generic analysis is needed. We must consider whether the technology is ready to be disseminated, and if so, how. Until recently these questions were seldom asked. As a result, modern medicine is replete with examples of technologies—drugs, surgical operations, laboratory tests—whose lack of effectiveness became evident, sometimes at great cost, only after they became part of routine medical practice.1 Lack of "effectiveness" of prenatal diagnosis for PKU could mean the abortion of fetuses unaffected with the disorder, and the unwanted birth of affected infants. The technology introduces a new ethical issue as well: the appropriateness of abortion for treatable conditions. Three issues should be addressed before new technologies are disseminated: validation, acceptance, and proliferation. I will use prenatal diagnosis for PKU to illustrate them. Several items to be discussed under "acceptance" also apply at the personal level. I pose them because they are important in deciding if and how the new technology should be made available, which is a matter of public policy. Lest one think these decisions have all been made for prenatal diagnosis for PKU, consider the following: (1) Research funding must continue to discover other restriction endonuclease sites, develop better probes, and simplify the techniques.
Quality and Quantity: From puericulture to eugenics

Why was there a thirty to forty-year wait between Galton's first formulation of eugenic ideas and the creation of formal eugenics organizations? As Chapter 2 has shown, there was no lack of awareness that France faced many problems associated with decline and decadence at the end of the nineteenth century; and there were in fact many proposals to remedy them on a biological basis. Some proposals, such as the solidarism of Leon Bourgeois, soon moved away from their scientific origins to assume a more clearly political character, but others, such as the social hygiene movement, developed along strikingly similar lines to eugenics. As will be seen in this chapter, hereditarian ideas were also well enough known in these biologically based reform circles to produce several proposals of an explicit eugenic nature. For example, as early as 1862 Clemence Royer called in the preface to her translation of Darwin's Origin of species for allowing natural selection to do its job of eliminating “the weak, the infirm, the incurable, the wicked themselves and all the disgraces of nature.” The French also had available at an early date in their own language a contemporary study similar to Galton's Hereditary genius , thanks to the work of the Swiss botanist Alphonse Candolle, whose Histoire des sciences et savants appeared in 1873. The important point here is not the question of priority, but rather why it took so long in both the English and French-speaking worlds for these studies about the inheritance of superior intellectual qualities to inspire organized eugenic movements.
Thermoregulation of African and European Honeybees during Foraging, Attack, and Hive Exits and Returns

1. While foraging, attacking, or leaving or returning to their hives, both the African and European honeybees maintained their thoracic temperature at 30 °C or above, independent of ambient temperature from 7 to 23 °C (in shade). 2. Thoracic temperatures were not significantly different between African and European bees. 3. Thoracic temperatures were significantly different during different activities. Average thoracic temperatures (at ambient temperatures of 8–23 °C) were lowest (30 °C) in bees turning to the hive. They were 31–32 °C during foraging, and 36–38 °C in bees leaving the hive, and in those attacking. The bees thus warm up above their temperature in the hive (32 °C) before leaving the colony. 4. In the laboratory the bees (European) did not maintain the minimum thoracic temperature for continuous flight (27 °C) at 10 °C. When forced to remain in continuous flight for at least 2 min, thoracic temperature averaged 15 °C above ambient temperature from 15 to 25 °C, and was regulated only at high ambient temperatures (30–40 °C). 5. At ambient temperatures > 25 °C, the bees heated up during return to the hive, attack and foraging above the thoracic temperatures they regulated at low ambient temperatures to near the temperatures they regulated during continuous flight. 6. In both African and European bees, attack behaviour and high thoracic temperature are correlated. 7. The data suggest that the bees regulate thoracic temperature by both behavioural and physiological means. It can be inferred that the African bees have a higher metabolic rate than the European, but their smaller size, which facilitates more rapid heat loss, results in similar thoracic temperatures.
Should patients on vitamin K antagonists be treated differently

This editorial refers to ‘Edoxaban versus warfarin in vitamin K antagonist-experienced and naive patients with atrial fibrillation’, by M.L. O'Donoghue et al. , on page doi: 10.1093/eurheartj/ehv014. Relative to warfarin, non-vitamin K oral anticoagulants (NOACs) are at least as good at preventing stroke or systemic embolism, cause less haemorrhagic stroke, and result in modestly lower mortality.1 Thus, the European Society of Cardiology has recommended NOACs in place of vitamin K antagonists (VKAs) in most patients with atrial fibrillation (class IIa, level of evidence A).2 According to one report, the use of NOACs in the USA has increased to > 60% of prescriptions for patients being initiated on oral anticoagulation.3 However, patients already treated with VKAs are usually not switched to NOACs.4 The low rates of switching from VKAs to NOACs relate to multiple factors including patient preference, medication cost, and clinical factors such as severe renal impairment. There is a common perception that a patient who is stable on a VKA will derive less benefit from a NOAC than a “VKA-naive”, patient who has not been previously treated with a VKA. The question remains whether or not this perception is supported by evidence. Not only does prior use of a VKA influence decisions to use a NOAC, but so does the degree of International Normalized Ratio (INR) control on a VKA, as measured by the time in therapeutic range (TTR). The prevailing opinion is that switching to a NOAC is less beneficial for patients on a VKA with a high TTR. In the Atrial fibrillation Clopidogrel Trial with Irbesartan for prevention of Vascular Events (ACTIVE W) trial, patients who were at centres …
Chemicals Call Bacteria, and A New Membrane Protein Machine Answers

A major challenge in biology is the discovery of the processes controlled by the roughly one-third of genes with no known function. One approach being explored to address this problem is the use of small molecules in conjunction with genetics—chemical genetics. A short review of this field is provided as an introduction to a series of papers in this issue of Cell in which a new type of chemical genetics revealed the function of a new outer membrane protein complex in bacteria.
Social Stress Exacerbates Focal Cerebral Ischemia in Mice

Background and Purpose — The purpose of the present study was to determine whether exposure to stress or elevated corticosterone concentrations in the days preceding cerebral ischemia exacerbates ischemic injury as assessed by histological and behavioral outcomes. Methods — For 7 consecutive days, male C57/BL6 mice were exposed to social stress for 45 minutes or injected with 1 mg/kg corticosterone or vehicle. The animals exposed to social stress were injected with either 1 mg/kg mifepristone, a glucocorticoid receptor antagonist, or the vehicle 30 minutes before stress. On the seventh day, all animals were trained in a passive avoidance task. Twenty-four hours after training, the animals were subjected to 60 minutes of intraluminal middle cerebral artery occlusion (MCAO) or sham surgery. At 72 hours of reperfusion, the animals were tested for retention of the passive avoidance task, and infarction size was determined. Results — Animals subjected to chronic social stress or treated with exogenous corticosterone before MCAO exhibited larger infarcts and reduced retention of passive avoidance compared with the nonstressed MCAO control. The effects of social stress on infarct volume and passive avoidance were reversed by pretreatment with mifepristone. There was no difference between stressed and control groups in physiological parameters or reduction of laser-Doppler flow signal during MCAO or reperfusion. Conclusions — Prior exposure to social stress increases infarction volume and exacerbates cognitive deficits associated with transient cerebral ischemia. The mechanism underlying the effects of stress on stroke outcome likely involves corticosterone acting through glucocorticoid receptors to increase subsequent ischemia-induced neuronal death.
Videofluoroscopy in the rehabilitation of swallowing dysfunction.

Videofluoroscopy and cineradiography have been used for decades to examine the gastrointestinal tract and specifically the oropharynx [1]. Recently, videofluoroscopy has been described as being useful for identifying the cause of aspiration [2]. This paper describes how videofluoroscopy may be used for treatment planning in rehabilitation. This unique application of videofluoroscopy is the product of efforts on the part of the author and her colleagues at The Good Samaritan Hospital-Johns Hopkins Swallowing Rehabilitation Program, which was launched in 1980. The rationale for using videofluoroscopy for rehabilitation, the implementation of videofluoroscopy for rehabilitation, and indications for using specific rehabilitation techniques during videofluoroscopy will be discussed.
Differential dissolution of a Pleistocene reef in the ground-water mixing zone of coastal Yucatan, Mexico

A geochemical explanation is provided for the extensive dissolution observed along the carbonate coast of the Yucatan Peninsula, Mexico. Mixing of fresh ground water with subterranean Caribbean seawater generates a highly reactive geochemical zone that enhances aragonite and calcite dissolution and permits neomorphism of aragonite. Mixing-zone dissolution caused by ground-water discharge is a major geomorphic process in developing caves, coves, and crescent-shaped beaches along the Yucatan coast. Such dissolution has probably been a significant control on permeability and porosity distribution in carbonate rocks in the geologic record.
Report on Dr. Lombard's Original Research on the Voice Reflex Test for Malingering: Contribution à la Seméiologie de la Surdité, Un Noveau Signe pour en Devoiler la Simulation

A report is given in translation concerning the initial experimentation by Dr. Lombard (1910) with his voice reflex test for nonorganic deafness. The technique is described as useful in the differential diagnosis of certain cases of unilateral and bilateral sensory neural deafness. Various sources of the masking stimulus are enumerated and testing methods are outlined. The Lombard voice reflex test is projected as a potentially valuable contribution to the field of forensic medicine.
A delivery model for overcoming psycho-behavioral barriers to exercise

Abstract Objective To examine the effects of a values-based wellness intervention on physical fitness and perceived barriers to exercise. Design Study was a one-group pre-test–post-test design. Participants were 58 university faculty and staff who volunteered to participate in a 10-week campus wellness program, based on the Disconnected Values Model (DVM), for improving exercise habits. Method Participants completed pre- and post-intervention measures of fitness (percent body fat, cardiovascular fitness, and upper- and lower-body muscular strength), disconnected values (job, health, happiness, family, work/life balance), and a variety of perceived internal and external barriers to exercise. Results Participants showed significantly improved fitness scores at post-test ( p p p Conclusion A values-based intervention increased participants’ exercise behaviors and reduced their perceived exercise barriers. Implications of the results supporting the DVM are presented.
Genomic structure, functional comparison, and tissue distribution of mouse Cd59a and Cd59b

CD59 is a crucial complement regulatory protein that inhibits the terminal step of the complement activation cascade by interfering with the binding of C9 to C5b-8, thus preventing the formation of the membrane attack complex (MAC). We recently reported that the mouse genome contains two Cd59 genes, while the human and rat genomes each contain only one Cd59 gene (Qian et al. 2000). Here, we describe the genomic structure, comparative activity, and tissue distribution of these two mouse genes, designated Cd59a and Cd59b. The mouse Cd59 genes encompass a total of 45.6 kb with each gene having four exons. Cd59a spans 19 kb, and Cd59b spans 15 kb, with approximately 11.6 kb of genomic DNA separating the two genes. The overall sequence similarity between Cd59a and Cd59b is approximately 60%. The sequence similarity between exon 2, exon 3, and exon 4 and the respective flanking regions between the two genes is over 85%, but exon 1 and its flanking regions are totally different. Comparative studies of the activity of both genes as inhibitors of MAC formation revealed that Cd59b has a specific activity that is six times higher than that of Cd59a. Using polyclonal antibodies specific to either Cd59a or Cd59b, we showed that Cd59a and Cd59b are both widely expressed in the kidneys, brain, lungs, spleen, and testis, as well as in the blood vessels of most mouse tissues. Interestingly, testicular Cd59a appeared to be expressed exclusively in spermatids, whereas Cd59b was expressed in more mature sperm cells. These results suggest that even though Cd59a and Cd59b are expressed in multiple tissues, they may play some different roles, particularly in reproduction.
The donor properties of positively charged ligands. Pseudo-tetrahedral COII and NiII complexes containing mono-quaternized ditertiary phosphines

Abstract The halide salts of the mono-quaternized ditertiary phosphines, 1,2-bis(diphenylphosphino)ethane and 1,1-bis(diphenylphosphino)methane, abbreviated as (PCH 2 CH 2 P + ) and (PCH 2 P + ) respectively, react under anhydrous conditions with the cobalt(II) and nickel(II) halides, forming crystalline compounds of stoichiometry MX 2 . (PCH 2 CH 2 P + X and MX 2 . (PCH 2 P + )X, where M = Co II and Ni II and X = Cl, Br, I. On the basis of their vibrational and d-d electronic spectra, magnetic properties, and X-ray powder diffraction patterns. these compounds are formulated as the high-spin, four-coordinate species [MX 3 (PCH 2 CH 2 P + )] and [MX 3 (PCH 2 P + )], having a pseudo-tetrahedral stereochemistry with C 3v symmetry.
A structural comparison of concanavalin a and tomato bushy stunt virus protein

Significant structural equivalence has been found among the polypeptide folds of the two tomato bushy stunt virus (TBSV) subunit domains and concanavalin A. This suggests gene duplication in the TBSV coat protein and leads to speculation on common functional properties of concanavalin A and viral coat proteins.
Effect of inosine on iron absorption in rats.

SummaryInosine administered intravenously at time of iron absorption increased the amount of iron absorbed by 50 to 100% in rats.
Bilingual aphasia: a theoretical and clinical review.

Purpose To provide an overview of the potential bilingual client population in the United States, present current neurolinguistic and psycholinguistic views of bilingualism in adults with and witho...
The quality option implicit in futures contracts

Abstract The quality option implicit in futures contracts allows the short position to satisfy the contract by delivering one of a variety of specified assets. If, at the time the contract is purchased, knowledge of which of the allowed assets will be cheapest at maturity is uncertain, then the quality option will have value. The greater the value of this option, the lower will be the futures price. This paper presents, and tests, a futures pricing model that incorporates the quality option aspect of commodity futures contracts. Our research shows that the quality option has a significant impact on futures prices.
Evaluation of cisatracurium, a new neuromuscular blocking agent, for tracheal intubation.

The primary objective of this study was a blinded, randomized comparison of the recommended intubating dose of atracurium (0.5 mg·kg−1) with an approximately equipotent dose of cisatracurium (0.1 mg·kg−1) during N20/02/propofol/ fentanyl anaesthesia. Eighty ASA physical status 1 or 2 patients, 18–70 yr of age, within 30% of ideal body weight, scheduled for elective low to moderate risk, surgical procedures were studied. Adductor pollicis evoked twitch responses were measured with a Grass FT 10 force displacement transducer (Grass Instruments, Quincy, MA) and continuously recorded on a Gould multichannel polygraph (Gould Instrument Systems, Cleveland, OH) after induction of anaesthesia. Increasing the initial dose of cisatracurium (from 0.1 to 0.15 and 0.2 mg·kg−1, decreased mean time of onset (from 4.6 to 3.4 and 2.8 min, respectively), and increased mean time of clinically effective duration (45 to 55 and 61 min, respectively). Recovery to a T4:T1 ratio of 0.7 occurred approximately seven minutes following administration of the reversal agent neostigmine for all treatment groups. Intubation conditions were good or excellent in over 90% of patients in all treatment groups (two minutes after approximately 2 x ED95 doses of cisatracurium or atracurium and 1.5 minutes after 3 × and 4 × ED95 doses of cisatracurium). The intubation results reported in this study together with the combination of predictable recovery from neuromuscular block and apparent haemodynamic stability make cisatracurium a potentially useful muscle relaxant in clinical practice.
Endoscopic repair of traumatic CSF rhinorrhea in a pediatric patient

Cerebrospinal fluid (CSF) rhinorrhea typically results from trauma to the skull base, producing leaks through either the cribiform plate region or the sphenoid bone. Traditional approaches to the repair of such leaks include a frontal craniotomy or external ethmoidectomy. An endoscopic approach through the nose has also proven to be successful. A 7-year-old male suffered traumatic CSF rhinorrhea and development of a meningocele in the region of the cribiform plate. After demonstrating the site of the leak with fluorescein dye, the defect was repaired via a transnasal endoscopic approach. The evaluation of the child with CSF rhinorrhea, including the presenting symptoms and signs and the radiographic assessment, is presented. The variety of approaches, types of repair and post-operative care are also discussed.
The face of high risk prostate cancer

To define high risk prostate cancer using prostate cancer specific mortality as the key outcome metric. Data from two population based cohorts of men from Connecticut who were diagnosed with localized prostate cancer were analyzed to determine the natural history of prostate cancer and the impact of treatment on long term survival. Men with Gleason 7–10 prostate cancer and a potential survival of 10 years have a high risk of dying from their disease if they elect active surveillance. Surgery appears to offer an improved survival for these men when compared to radiation therapy or observation. Men diagnosed with Gleason 6 tumors in the contemporary era are more likely to harbor low risk prostate cancer when compared to historical series. Our studies confirm that high risk prostate cancer is best identified by Gleason score 7–10, but challenge the concept that men with high-grade disease are less likely to benefit from radical surgery. Men who have rising PSA values following treatment with either surgery or radiation have residual prostate cancer and are at very high risk of dying from prostate cancer within 10 years.
Low-threshold strain-compensated InGaAs(N) (/spl lambda/ = 1.19-1.31 μm) quantum-well lasers

Highly strained (/spl Delta/a/a /spl sim/ 2.5%) In/sub 0.4/Ga/sub 0.6/As and In/sub 0.4/Ga/sub 0.6/As/sub 0.995/N/sub 0.005/-quantum-well (QW) active lasers utilizing strain-compensating InGaP-GaAsP buffer layers and GaAs/sub 0.85/P/sub 0.15/ barrier layers, grown by metal-organic chemical vapor deposition (MOCVD), are demonstrated with lasing emission wavelength of 1.185 and 1.307 /spl mu/m, respectively. Threshold and transparency current density for the strain compensated InGaAsN QW lasers, with emission wavelength of 1.295 /spl mu/m, are measured to be as low as 290 A/cm/sup 2/ (L = 1500 /spl mu/m) and 110 A/cm/sup 2/, respectively, with characteristic temperature of T/sub 0/ and T/sub 1/ of 130 K and 400 K.
More on the Bruhat order for (0, 1)-matrices

Abstract Let A ( R , S ) denote the class of all (0, 1)-matrices with row sum vector R and column sum vector S. Continuing an earlier investigation of the Bruhat order and secondary Bruhat order (both of which extend the classical Bruhat order on permutations of {1, 2, … , n}) on A ( R , S ) , we provide a counterexample to a conjecture of Brualdi and Hwang which shows that these two orders are not in general the same. We characterize the cover relation for the secondary Bruhat order. We also study in more detail certain classes A ( R , S ) where R = S = (k, k, … , k), a constant vector. We show that for k = 2 the Bruhat order and secondary Bruhat order are the same, but this is not always so when k = 3.
The current state of diversity and multicultural training in urology residency programs.

Purpose: The American population continues to increase in ethnic diversity. However, the medical work force has lagged behind these population trends. We evaluated the extent of diversity and perceived barriers to multicultural training in American urology programs.Materials and Methods: A 25-question nonvalidated diversity questionnaire was distributed electronically to 112 American urology residency program directors.Results: A total of 62 program directors (55%) responded, representing all American Urological Association geographic regions nationwide. Of the respondents 92% were male and 90% were older than 40 years. During their residency 44% of respondents reported no female co-residents and 51% reported no co-residents of color. As faculty, 40% of respondents reported no female colleagues and 49% reported no colleagues of color. Of the respondents 75% identified no formal process to recruit faculty of color. With regard to current residency training 36% of respondents reported 1 or fewer female resi...
Interdecadal variability over the North Pacific in a multi-century climate simulation

Interdecadal variability in the North Pacific region is investigated in a 500-y control integration of the Hamburg ECHAM+LSG coupled ocean-atmosphere general circulation model. The spectrum is predominantly red, but a significant peak with a period of about 18 y is detected in the spectrum of sea surface temperature (SST). This peak is shown to be associated with an irregular oscillation that involves both the model ocean and atmosphere. The SST, sea-level pressure, and geopotential height at 500 hPa all undergo a primarily standing oscillation with an extensive monopole structure centered near the date line. The surface anticyclone is situated to the northeast of the warm SST anomaly, and there is a small westward tilt with height; temporal changes are approximately in phase. The anomalous surface heat flux accompanying the warm phase of SST is primarily out of the ocean, but is compensated by anomalous warm advection by surface currents, allowing the SST anomaly to persist. Oceanic thermocline anomalies propagate northward in the western Pacific, and lag the atmosphere indicating a disequilibrium with the atmosphere; sub-surface thermal advection appears to play an important role. A comparison is made between the model's 18-y oscillation and oscillatory components identified in an analysis of the GISST observational SST dataset, which have periods of approximately 6 and roughly 30 y.
Influence of Silane Treatment and Filler Fraction on Thermal Expansion of Composite Resins

The coefficient of thermal expansion of experimental composite materials containing either silane-treated or untreated fillers in a triethylene glycol dimethacrylate (TEGDMA) matrix was investigated. The results show that an inverse linear relationship existed between volume fraction filler and coefficient of thermal expansion. No differences were seen between silane-treated and untreated composites, while it was found that repeated heating (aging) caused the thermal expansion to decrease for all material combinations.Reduction in the coefficient of thermal expansion with increased filler fraction of unbonded filler indicates that the polymerization shrinkage of the matrix induces hoop stresses around the fillers.By use of a simplified theoretical model (Appendix), these stresses could be estimated. These estimates revealed that the induced stresses were remarkably high, and that increased filler fraction increased the tensile stress level surrounding the filler particles. Since these tensile stresses cou...
Histologic, Physical and Chemical Investigation of Myositis Ossificans Traumatica

Histologic, physical and chemical analyses of the excised bony mass from a case of myositis ossificans traumatica were carried out. X-ray diffraction showed that the newly formed bone was an intermediate fluorhydroxylapatite. Infrared spectroscopy and chemical analysis supported this finding. Contrary to articular free bodies the mineral part of the bony mass from the myositis ossificans investigated was formed most probably in a basic environment.
A comparison of platelet parameters in EDTA- and citrate-anticoagulated blood in dogs.

Background Platelet aggregates are a common artifact in canine blood. Aggregates may affect the accuracy of platelet counts, with important consequences for patient care. Objectives The purpose of this study was to determine if platelet counts in dogs were more accurate if blood was collected into citrate instead of EDTA as an anticoagulant. Methods Blood was collected from 50 dogs with neoplasia admitted to the oncology service at Cornell University. EDTA and citrate Vacutainer tubes were filled with blood in random order. Platelet counts and parameters (mean platelet volume [MPV], platelet distribution width [PDW], mean platelet component concentration [MPC], platelet component distribution width [PCDW], and automated platelet clump count [APCC]) were determined using an optical-based hematology analyzer (ADVIA 120). Blood smears from each anticoagulated sample were scored visually for platelet aggregates. Results The median platelet count was significantly lower (median decrease, 27 x 10(9)/L) in citrate-anticoagulated blood compared with EDTA-anticoagulated blood. This was attributed to platelet activation and aggregation: significantly more aggregates were seen in smears of citrate- than of EDTA-anticoagulated blood. Aggregates were typically small and not detected by the analyzer. Also, the MPV and MPC (or density) were significantly higher (median increase, 3 fL) and lower (median decrease, 33 g/L) in citrate-anticoagulated samples, respectively. Conclusions Platelets aggregate, likely from activation, when blood from dogs with neoplasia is anticoagulated with citrate for hematology testing, resulting in lower platelet counts. Citrate also yields inaccurate results for MPV and MPC, likely because of inadequate sphering of platelets. Thus, we recommend that citrate not be used as an anticoagulant when accurate platelet counts are desired in dogs.
Molecular Design of Free Volume as a Route to Low-κ Dielectric Materials

Polymers incorporating the triptycene subunit were prepared for the molecular-level design of low dielectric constant (low-κ) materials that can be used to manufacture faster integrated circuits. Triptycenes having restricted rotation by multiple point attachment to the polymer backbone are shown to introduce free volume into the films, thereby lowering their dielectric constants. The triptycene containing polymers exhibit a number of desirable properties including low-water absorption and high thermal stability. Systematic studies wherein comparisons are made between two separate classes of triptycene polymers and their non-triptycene containing analogues demonstrate that proper insertion of triptycenes into a polymer backbone can give rise to a reduction in the material's dielectric constant while also improving its mechanical properties. These characteristics are desired by the semiconductor industry for the next generation of microprocessors and memory to provide insulation of the increasingly shrinki...
Evolution of massive stars in very young clusters and associations

Statistics concerning the stellar content of young galactic clusters and associations which show well defined main sequence turnups have been analyzed in order to derive information about stellar evolution in high-mass galaxies. The analytical approach is semiempirical and uses natural spectroscopic groups of stars on the H-R diagram together with the stars' apparent magnitudes. The new approach does not depend on absolute luminosities and requires only the most basic elements of stellar evolution theory. The following conclusions are offered on the basis of the statistical analysis: (1) O-tupe main-sequence stars evolve to a spectral type of B1 during core hydrogen burning; (2) most O-type blue stragglers are newly formed massive stars burning core hydrogen; (3) supergiants lying redward of the main-sequence turnup are burning core helium; and most Wolf-Rayet stars are burning core helium and originally had masses greater than 30-40 solar mass. The statistics of the natural spectroscopic stars in young galactic clusters and associations are given in a table.
Gene replacement strategies to test the functional redundancy of basic helix-loop-helix transcription factor.

Basic helix–loop–helix (bHLH) transcription factors control developmental decisions for a wide range of embryonic cell types. Hand1 and Hand2 are closely related bHLH proteins that control cardiac, craniofacial, and limb development. Within the developing heart, Hand1 expression becomes restricted predominantly to the left ventricle, whereas Hand2 becomes restricted predominantly to the left ventricle, for which findings have shown each Hand factor to be necessary for normal chamber formation. Forced overexpression of Hand1 throughout the early developing heart induces abnormal interventricular septal development, with resulting pathogenesis of congenital heart defects. To investigate the potential transcriptional mechanisms involved in heart morphogenesis by Hand2, this study used a replacement targeting approach to knock Hand2 into the Hand1 locus and ectopically express one copy of Hand2 within the endogenous Hand1 expression domain in the developing hearts of transgenic mice. The findings show that high-percentage Hand1Hand2 chimeras die at birth and exhibit a range of congenital heart defects. These findings suggest that Hand factors may act via unique transcriptional mechanisms mediated by bHLH factor partner choice, supporting the notion that alterations of Hand factor stoichiometry may be as deleterious to normal heart morphogenesis as Hand factor loss of function.
Prelarva and larva of Opilioacarus (Neocarus) texanus (Chamberlin and Mulaik) (Acari: Opilioacarida) with notes on the patterns of setae and lyrifissures

The prelarva and larva of Opilioacarus (Neocarus) texanus (Chamberlin and Mulaik, 1942) are described based on reared specimens. The larval description focuses on the pattern of setae, lyrifissures, and glands in order to test the hypothesis that these structures can be homologized among larvae of all suborders of the Parasitiformes. The distribution pattern of lyrifissures and setae on the hysterosoma of opilioacarid larvae appears to be the most complete pattern of these structures in the order Parasitiformes, and strongly suggests an ancestral segmental arrangement of the cuticular sensillae and glands. Unlike the condition for the post-larval instars, sensillae (setae and lyrifissures) on the palps, hysterosoma, and legs II-III of the larva can be homologized among larvae in all suborders. Homologies among suborders could not be established for the sensillae and glands of the propodosoma and most segments of legs I.
Basic demographics, health practices, and health status of U.S. medical students.

Background There has never been a nationally representative survey of medical students’ personal health-related practices, although they are inherently of interest and may affect students’ patient-counseling practices. Methods To determine basic health practices and status, a survey was conducted of medical students (n =2316 individuals responding to ≥1 survey) in the Class of 2003 at freshman orientation, entrance to wards, and senior year in a nationally representative sample of 16 medical schools (response rate=80.3%). Results Most medical students (84%) reported never having smoked cigarettes, and both genders typically drank two drinks per drinking episode (with bingeing more common among men). Students exercised a median of at least 4 hours per week, and preferred strenuous exercise. Medical students across all years and both genders reported a median of 7 hours of sleep per night. Nearly all (97%) reported their health to be at least good, typically with 1 or fewer days of poor physical or mental health in the past month. Both genders (particularly women) were unlikely to be overweight or obese. Reported rates of any chronic condition were ≤2% except for hypertension among men, and obesity, dyslipidemia, and depression in both genders. Unlike their other relatively positive behaviors compared with their peers, medical students had variable rates of preventive screening. Conclusions Medical students in the United States were healthy, and reported many good health behaviors when compared with other young U.S. adults. However, for some, health behaviors and personal health practices either did not meet national goals or placed students at risk.
Water-vapor line broadening and shifting by air, nitrogen, oxygen, and argon in the 720-nm wavelength region

High-resolution spectroscopic measurements of H2O vapor in the 720-nm wavelength region were conducted to investigate the broadening and shifting of H2O lines by air, nitrogen, oxygen, and argon over a wide range of pressures and temperatures. For each of the buffer gases under study, a linear relationship was found between the widths and the shifts, with the broader lines having the smaller pressure shifts. The pressure shifts measured compared favorably with theoretical values reported by Bykov et al. (1988). The temperature-dependence exponents for air-broadening were found to be J-dependent, with the lower-J lines having the higher exponents.
Temperature-dependent thermal properties of a shape memory alloy/MAX phase composite: Experiments and modeling

Abstract A shape memory alloy/MAX phase composite, namely NiTi/Ti 3 SiC 2 composite, was fabricated using spark plasma sintering at 1233 K under 100 MPa for 8 min, from a NiTi/Ti 3 SiC 2 powder mixture with a 50/50 v/v ratio. The thermal diffusivity was measured at both ambient and elevated temperatures up to 1224 K using a laser flash analyzer. The specific heat at constant pressure was measured over the temperature range 300–600 K using a differential scanning calorimeter. The thermal conductivity was then calculated from the thermal diffusivity, specific heat and density. To validate the experimental results, a survey of data on the thermal diffusivity, specific heat and thermal conductivity of monolithic NiTi and Ti 3 SiC 2 was carried out. Finite-element modeling of a micromechanics-based representative volume element was carried out to predict the thermal conductivity of the NiTi/Ti 3 SiC 2 composite. An agreement between the experimental and finite-element results was found.
Calcified pulmonary metastases from medullary carcinoma of the thyroid

A case of calcified pulmonary metastases from medullary carcinoma of the thyroid is reported. This uncommon cause of multiple calcified pulmonary nodules is demonstrated on a computerized tomography (CT) scan and proven by pathology.
Effect of phospholipase A2 inhibitors on the release of arachidonic acid and cell viability in cold-stored hepatocytes.

Abstract We investigated the effect of phospholipase A 2 (PLA 2 ) inhibitors on PLA 2 activity and cell viability in cold-stored rat hepatocytes. The cells were radiolabeled with [ 3 H] arachidonic acid (AA) and cold stored in the University of Wisconsin (UW) solution containing various PLA 2 inhibitors. PLA 2 activity was determined by measuring the total free (cellular + supernatant) AA by thin-layer chromatography after inhibiting reacylation of free AA with inhibitors of energy production (carbonyl cyanide m -chlorophenylhydrazone + iodoacetate). Aristolochic acid, chlorpromazine, and quinacrine in the UW solution showed a significant inhibitory effect throughout 48 h cold storage but only at relatively high concentration. PLA 2 activity was also suppressed (58% of control) by trifluoperazine (50 μM), but its effect was limited to only 24 h. In contrast, pretreatment of the cells prior to hypothermic preservation with trifluoperazine (10 to 100 μM) suppressed PLA 2 activity during 48 h storage. Inclusion of calmodulin antagonist W-7 did not affect PLA 2 activity. Thus, the inhibitory activity of these agents appears unrelated to Ca–calmodulin–phospholipid interaction but to have an inhibitory effect on PLA 2 activity. To study the effects of PLA 2 inhibitors on cell viability, lactate dehydrogenase (LDH) release was measured in the presence or absence of inhibitors upon rewarming cold-stored cells in Krebs–Henseleit buffer for 2 h at 37°C. None of the inhibitors tested improved cell viability after 48 h storage. Thus, although PLA 2 inhibitors blocked PLA 2 activity, there was no suppression of LDH release. PLA 2 may play a minor role in preservation/reperfusion injury to cold-stored hepatocytes.
Tracking of shear bands I. The one-dimensional case

Abstract We develop a model for the dynamics of a fully developed shear band that allows effective computation across several length scales. From a macroscopic point of view, a shear band is a discontinuity in tangential velocity that supports a shear stress. Numerical simulation of the full system of governing equations reveals that the internal structure of the band consists of a quasistatic core surrounded by a thermal layer. We show that the shear band can be modeled as a composite structure whose evolution is govemed by an integral equation, coupled to the external flow through jump conditions. We establish the accuracy of the model equations by numerical experiments.
Diagnosability of discrete event systems and its applications

As man-made systems become more and more complex, diagnostics of component failures is no longer an easy task that can be performed based on experience and intuition. Therefore, it is important to develop a systematic approach to diagnostic problems. Diagnostics can be done either on-line or off-line. By on-line diagnostics, we mean diagnostics performed while the system to be diagnosed is in normal operation. On the other hand, in off-line diagnostics, the system is not in normal operation. We will study both on-line and off-line diagnostics in this paper and identify main features and differences of these two types of diagnostics. We will also introduce the concept of diagnosability and study its properties, all in the framework of discrete event systems. This study is motivated by diagnostic problems in the automotive industry and we will emphasize its applications.
Evaluation of integral dose in cranio-spinal axis (CSA) irradiation with conventional and helical delivery

In cranio-spinal axis (CSA) irradiation, patients are usually treated in the prone position with junctions between cranial and spinal fields. Collimator angle and pedestal rotations are introduced to obtain coplanar alignment of the matched junction. Furthermore, daily moving junctions are commonly used to feather out the junctional dose as additional safe-guards to avoid radiation myelopathy.Helical tomotherapy integrates linear accelerator and CT technology capable of delivering CSA treatment without geometric matches or feathering of junctions. The patient is treated with helical beams in the supine position. Since CSA is used mainly in the pediatric population, the potential increase in integral dose to structures or the whole body from linac- or tomotherapy-based IMRT raises concerns of increased rates of secondary malignancies.In this study, we will present an integral dose comparison between conventional CSA (3D) and helical delivery to the CSA (TOMO) utilizing the Tomotherapy Hi-ART system for thr...
Synthesis of 25-hydroxy-[26,27-3H]vitamin D2, 1,25-dihydroxy-[26,27-3H]vitamin D2 and their (24R)-epimers

Abstract Synthesis of a C-24-epimeric mixture of 25-hydroxy-[26,27-3H]vitamin D2 and a C-24-epimeric mixture of 1,25-dihydroxy-[26,27-3H]vitamin D2 by the Grignard reaction of the corresponding 25-keto-27-nor-vitamin D2 and 1α-acetoxy-25-keto-27-nor-vitamin D3 with tritiated methyl magnesium bromide is described. Separation of epimers by high-performance liquid chromatography afforded pure radiolabeled vitamins of high specific activity (80 Ci/mmol). The identities and radiochemical purities of 25-hydroxy-[26,27-3H[vitamin D2 and 1,25-dihydroxy-[26,27-3H]vitamin D2 were established by cochromatography with synthetic 25-hydroxyvitamin D2 or 1,25-dihydroxyvitamin D2. Biological activity of 25-hydroxy-[26,27-3H]vitamin D2 was demonstrated by its binding to the rat plasma binding protein for vitamin D compounds, and by its in vitro conversion to 1,25-dihydroxy-[26,27-3H]vitamin D2 by kidney homogenate prepared from vitamin D-deficient chickens. The biological activity of 1,25-dihydroxy-[26,27-3H]vitamin D2 was demonstrated by its binding to the chick intestinal receptor for 1,25-dihydroxyvitamin D3.
Student-life stress in Education and Health Service majors

In order to better understand the effects of student-life stress on Education and Health Service majors (n = 195) at a private, religious, Midwestern university in the USA, we assessed student perception of overall stress level and physical stress level using the Student-life Stress Inventory. The targeted sample consisted of students with declared majors that lead to careers involving interaction with vulnerable populations (i.e., children, individuals with disabilities, patients). Women in this study experienced a significantly higher (F = 7.092 [1195], p = .008) overall stress level than their male counterparts. When the physical stress reaction scores were isolated, women still experienced significantly higher stress levels (F = 7.758 [1195], p = .01). Regardless of gender, seniors and graduate students had an overall stress difference that was 11 points below that of freshman students in overall stress scores. There was a significant difference in the overall stress score (F = 6.484 [2181], p = .001)...
Low calcium reperfusion of ischemic myocardium

Abstract The mechanisms underlying protection of ischemic myocardium by reperfusion with solutions containing reduced concentrations of calcium (Ca) were studied in isolated vascularly perfused rabbit interventricular septa at 37°C. After 45 min of total ischemia adenosine triphosphate (ATP), and phosphocreatine (PC) contents fell to 6.8 ± 0.82, and 12.4 ± 2.0 μ m /g dry tissue (d t ) (± s.e.m. ). After 5 min of reperfusion with 0.75 m m Ca these values had recovered significantly to 10.3 ± 1.0, and 33.3 ± 3.6, (μ m /g d t ), while reperfusion with 2.5 m m Ca produced 5.9 ± 1.0 and 22.0 ± 2.6 (μ m /g d t ). The significantly greater recovery of ATP and PC after 0.75 m m Ca reperfusion persisted after an additional 25 min of reperfusion with 2.5 m m Ca when compared to septa reperfused for the entire 30 min with 2.5 m m Ca. When mechanical work was reduced by cessation of stimulation during the first 5 min of reperfusion, ATP, PC and total creatine (TC) recovery were significantly improved in muscles exposed to 2.5 m m Ca but showed no additional improvement in muscles reperfused with 0.75 m m Ca. A further reduction to 100 μ m Ca reperfusion in quiescent muscles did significantly improve ATP, PC and TC recovery. Quiescence achieved with 16.0 m m K impaired ATP, PC and TC recovery. This effect was reversed by 100 μ m Ca reperfusion. Measurements of mitochondrial oxygen consumption, respiratory control and ADP O showed results parallel to the ATP, PC and TC determinations. Both mechanical work and Ca itself influence mitochondrial respiration, ATP, PC and TC content after ischemia. As previously demonstrated for mechanical function, metabolic recovery can be improved by interventions limited to the first 5 min of reperfusion.
TIME‐LAGS IN CROSS‐LAG CORRELATION STUDIES: A COMPUTER SIMULATION

The cross-lag correlation method has gained increased use in recent years as a technique which can be used to evaluate causality in longitudinal behavioral research. However, the effect of selecting an incorrect time-lag has remained largely unexplored. This research reports the results of a computer simulation designed to evaluate what happens to the cross-lag correlation under different time-lags. The results of the simulation indicate that the cross-lag method is relatively insensitive to errors in the selection of the time-lag. Nevertheless, it is better to err on the “early” side than on the “late” side. A research design is suggested for further empirical investigation of the effect of the choice of time-lags.
Online talk: does it matter?

Purpose – The purpose of this paper is to examine stocks that are most actively discussed by online posters and see if the messages posted about these stocks have information or if they are just noise.Design/methodology/approach – This study uses messages posted on TheLion.com, which reports a real time list of the ten most actively discussed stocks. The stocks in this list at the daily market close during 2005‐2006 are examined. An event study is performed to estimate the daily abnormal returns on these stocks. Contemporaneous and lead–lag regressions of abnormal returns against message posting activities are performed.Findings – Online posters prefer thinly traded micro‐cap stocks. On average, there is an abnormal return of 19.4 per cent on a stock the day it is one of the ten most talked about stocks. The number of messages posted about a stock on a given day is not only positively related with the stock's abnormal return on that day but it also positively predicts the next day's abnormal return.Resear...