cssi/SciSciGPT-SciSciNet huggingface dataset:
Activins are expressed early in Xenopus embryogenesis and can induce axial mesoderm and anterior structures.

Abstract We show that mammalian and Xenopus activins induce dorsal axial mesoderm and anterior structures in explants of Xenopus blastula cells that would otherwise form epidermis. The induced explants of animal cap cells can form notochord, muscle, neural tissue, and eyes all arranged in a rudimentary axial pattern. Activin A shares inductive properties and antigenic determinants with PIF, an inducing factor recently isolated from mouse macrophage culture supernatants. Genes encoding Xenopus activin β A and β B chains were cloned. Activin β B transcripts are first detected in Xenopus blastula, whereas activin β A transcripts do not appear until the late gastrula stage. Recombinant Xenopus activin β B protein induces mesodermal and neural tissues similar to those induced by mammalian activin A and PIF. Furthermore, ectopic expression of Xenopus activin β B produces a second body axis in embryos injected with synthetic mRNA. Our results suggest that early induction and axial patterning are accomplished by endogenous activin B, not activin A, in Xenopus.
Percutaneous endovascular abdominal aortic aneurysm repair.

In this prospective, nonrandomized study, we compared outcome with percutaneous femoral artery closure to that with open femoral arteriotomy in 95 patients who underwent endovascular AAA repair. Devices were introduced using 22 Fr and/or 16 Fr sheaths. The 8 Fr/10 Fr Perclose devices (Perclose Inc., Redwood City, CA) were used in an off-label "preclose technique." Thirty-three patients had bilateral open femoral arteriotomies, 44 patients had bilateral attempted percutaneous closure, and 18 patients had open femoral arteriotomy on one side and attempted percutaneous closure on the other side. Percutaneous closure was successful in 85% (47/55) of 16 Fr sheaths and 64% (29/45) of 22 Fr sheaths (p 0.05). Gender, previous femoral access, obesity, and iliac occlusive disease were not predictive of percutaneous failure. Procedural success for percutaneous AAA repair is affected by sheath size. Devices delivered through 16 Fr or smaller sheaths will have successful femoral artery closure rates of at least 85%.
Cycle time properties of the FDDI token ring protocol (extended abstract)

Communication technology now makes it possible to support high data transmission rates at relatively low cost. In particular, optical fiber can be used as the medium in local area networks with data rates in the range of 100 megabits per second. Unfortunately, local area network topologies and communication protocols that work well with lower speed media are not necessarily appropriate when the data transmission rate is scaled up by approximately an order of magnitude. Recognizing this fact, an ANSI sub-committee (ANSIX3T9) has been working for the past two years on a proposed standard for a token ring protocol tailored to a transmission medium with transmission rate in the 100 megabits per second range. The protocol is referred to as the FDDI (Fiber Distributed Data Interface) Token Ring protocol. The proposal for the standard is now quite mature and nearly stable.
Thermal variation of a Raman line width in calcite

Abstract A width measurement of the A1g Raman line in calcite ( ν = 1086 cm -1 ) over an extended temperature range (10°K to 660°K) is reported. The result is compared with a theory based on anharmonicity.
Critical issues for single-chamber manufacturing: the role of laser technology

Abstract Some critical issues confronting single-chamber, in situ processing are reviewed with an eye toward the role laser technologies are likely to play in enabling this emerging trend in microfabrication.
Cointegration tests of purchasing power parity: the case of Swiss exchange rates

Abstract This paper tests purchasing power parity (PPP) as a long-run equilibrium condition by examining the long-run relationshiop between exchange rates and wholesale price indices using cointegration tests. This paper avoids some of the problems of previous cointegration tests of PPP by using more precise data pretests and by not imposing a priori restrictions upon the cointegrating vector. Of the nine combinations of Swiss exchange rates and price indices examined, cointegration is detected in seven cases thus supporting PPP as a long-run equilibrium. (JEL F31, C32)
A low profile surface wave antenna equivalent to a vertical monopole antenna

This paper presents a novel surface wave antenna that can radiate vertical monopole type patterns with a low profile configuration. A horizontal dipole resides near a patch loaded grounded slab and it successfully transfers the energy from the feeding probe to the surface waves. The propagation and diffraction of surface waves generate monopole type radiation patterns. The advantage of the surface wave antenna is the attractive height: only 0.02 /spl lambda/ above the artificial ground plane, which is less than 10% of a typical vertical monopole.
Effects of immobilization stress on the pathogenesis of acute murine toxoplasmosis

Stress modulates a variety of immune responses. We investigated the effects of immobilization stress on the pathogenesis of acute murine toxoplasmosis, an infection in which cell-mediated immunity is of major importance in host defense. Repetitive overnight immobilization beginning 3 days prior to infection enhanced (p less than 0.05) the mortality of mice infected with a virulent strain (C56) of Toxoplasma gondii (77% vs 15% mortality in restrained and control mice, respectively). Daily immobilization for 14 days prior to infection abrogated (p less than 0.05) the lethal effect of immobilization, suggesting an adaptive mechanism. To explore the effect of immobilization with a less virulent strain, the Me49 strain of T. gondii was studied. Acute infection with T. gondii Me49 resulted in anorexia and weight loss, while spleen size and respiratory burst activity of peritoneal exudate cells were enhanced (p less than 0.01). Immobilization (twice daily for 2 h) did not significantly alter survival or other clinical features of acute T. gondii infection. In addition, immobilization suppressed (p less than 0.05) phorbol myristate acetate-stimulated release of superoxide anion by peritoneal exudate cells in healthy naive mice, but not in infected mice. These findings indicate that immobilization stress can alter the pathogenesis of acute T. gondii infection in healthy mice, but the effect of this stress paradigm will be influenced, in part, by the timing of the immobilization and the virulence of the strain of T. gondii.
Comparative effects of cycloheximide and puromycin on cerebral protein synthesis and consolidation of memory in mice

Abstract Cycloheximide was injected intracerebrally in mice in amounts which produced 94–95% inhibition of cerebral protein synthesis in the interval between 5 and 8 h after administration. Such animals learned to escape or avoid shock by choosing the correct limb of a T-maze normally 5 h after injection and had normal retention when tested 3 h later. In contrast, mice injected with puromycin in a dose which inhibited protein synthesis less than cycloheximide, had marked impairment of memory 3 h after training. Addition of cycloheximide to the puromycin solution antagonized its amnesic effect. The puromycin effect on memory 3 h after training is, therefore, probably not based on inhibition of synthesis of a protein required for memory storage. A possible role of protein synthesis in ‘consolidation’ of memory in mice is not supported by these experiments.
Exome Sequencing of Ion Channel Genes Reveals Complex Profiles Confounding Personal Risk Assessment in Epilepsy

Ion channel mutations are an important cause of rare Mendelian disorders affecting brain, heart, and other tissues. We performed parallel exome sequencing of 237 channel genes in a well-characterized human sample, comparing variant profiles of unaffected individuals to those with the most common neuronal excitability disorder, sporadic idiopathic epilepsy. Rare missense variation in known Mendelian disease genes is prevalent in both groups at similar complexity, revealing that even deleterious ion channel mutations confer uncertain risk to an individual depending on the other variants with which they are combined. Our findings indicate that variant discovery via large scale sequencing efforts is only a first step in illuminating the complex allelic architecture underlying personal disease risk. We propose that in silico modeling of channel variation in realistic cell and network models will be crucial to future strategies assessing mutation profile pathogenicity and drug response in individuals with a broad spectrum of excitability disorders.
Evaluation of a computer program for teaching laboratory diagnosis of acid-base disorders

A computer program was evaluated as a tool for increasing the diagnostic acumen of medical housestaff and students in identifying acid-base disorders. The participants were randomized into two groups; group A (N = 20) was encouraged to use the software, and group B (N = 19) was denied access. Pre- and post-tests were administered to delineate the groups' ability to identify correctly an acid-base disorder from laboratory data (electrolytes and arterial blood gas). During 6 weeks, group A used the computer for a mean of 2.83 h (range 1 to 6). The mean ± SE number of correct answers out of 20 questions, prior to use of the computer program, were 5.7 ± 0.8 (95% confidence interval 3.9 to 7.5) for group A and 5.2 ± 0.6 (95% confidence interval 3.9 to 6.5) for group B. These results were not statistically different. Correct responses increased significantly in group A to 10.3 ± 0.9 (P < 0.0001, 95% confidence interval 8.4 to 12.2) but did not increase significantly in group B. The data suggest that this software program was effective in increasing the diagnostic capabilities of medical housestaff and students for identifying acid-base disorders.
Estimation of scatterer volume density near a concentration gradient.

A general formulation of the echo received from a random scatterer ensemble illuminated by a short electromagnetic or sonic signal is developed. It is shown theoretically and confirmed experimentally with ultrasound, that a gradient in scatterer density will return an echo which is partially spatially coherent (i.e. specular). The surface of a random ensemble of uniform scatterers is shown to produce an echo from whose degree of coherence, the scatterer density and cross section can be calculated.
Immunohistopathologic features and therapy of conjunctival lichen planus

Lichen planus is an autoimmune disease that typically involves skin and the mucosa of the genitalia and mouth. Conjunctival involvement is rare, and the microscopic abnormalities of affected conjunctivae are not well characterized. We treated two patients with cicatrizing conjunctivitis and extraocular conjunctival lichen planus confirmed by biopsy. We found irregular, thickened basement membrane with reduplications similar to the findings in oral mucosa affected by lichen planus. The absence of basement membrane immunoreactants excluded ocular cicatricial pemphigoid. Results of laboratory tests for collagen vascular diseases including sarcoidosis and lupus were also negative. Treatment with 2% cyclosporine eyedrops controlled inflammation and stopped cicatrization in one patient who was followed up for 12 months. The other patient, in whom lichen planus was recently diagnosed, responded favorably to topical cyclosporine. Lichen planus should be included in the differential diagnosis of cicatrizing conjunctivitis and its immunohistopathologic features should be studied in conjunctival biopsies. Topical cyclosporine may be used successfully for conjunctival lichen planus.
A simple, reliable, and expandable monitor and control system for gas-exchange analysis.

Abstract A system of relatively low-cost but reliable components was assembled for time sharing a single analytical instrument in gas-exchange studies. Aside from an analytical instrument, recorder, gas standards, and study vessels or compartments, only a simple assembly of timers, motor-driven cams, microswitches, gas solenoid valves, and a single electronic relay were required. The system was developed for biological studies of photosynthesis and respiration, but can be readily adapted to air pollution and basic chemical problems.
Should all patients with atrial fibrillation be screened with echocardiography

Objective:To address a patient care problem suggested by a quality assurance study: Should physicians of patients with atrial fibrillation who have not had echocardiography performed be encouraged to obtain echocardiograms in order to discover heretofore undetected mitral stenosis, which could be treated with anticoagulation, in order to avert strokes?
Dehydroepiandrosterone, glucose-6-phosphate dehydrogenase, and longevity

Dehydroepiandrosterone (DHEA) is an abundantly produced adrenal steroid whose biological role has never been clarified. DHEA is a potent uncompetitive inhibitor of mammalian glucose-6-phosphate dehydrogenase (G6PDH) and as a consequence lowers NADPH levels and reduces NADPH-dependent oxygen-free radical production. Overproduction of oxygen-free radicals, or oxidative stress, upregulates inflammation and cellular proliferation and is believed to play a critical role in the development of cancer, atherosclerosis, and Alzheimer's disease, as well as the basic aging process. Both in vitro and in vivo experimental studies strongly indicate that DHEA and related steroids inhibit inflammation and associated epithelial hyperplasia, carcinogenesis, and atherosclerosis, at least in part, through the inhibition of G6PDH and oxygen-free radical formation. Recent epidemiological findings in Sardinian males bearing the Mediterranean variant of G6PDH deficiency are consistent with the hypothesis that reduced G6PDH activity has a beneficial effect on age-related disease development and longevity. Clinical trials with DHEA are encumbered by the high oral doses required as well as the conversion of DHEA into active androgens. The use of less androgenic congeners as well as non-oral formulations may facilitate testing of this class of compounds.
Hydrophobized triphenyl phosphonium derivatives for the preparation of mitochondriotropic liposomes: choice of hydrophobic anchor influences cytotoxicity but not mitochondriotropic effect.

Context: Nanocarrier-based strategies to achieve delivery of bioactives specifically to the mitochondria are being increasingly explored due to the importance of mitochondria in critical cellular p...
Vapor Pressure, Heat Capacity, and Density along the Saturation Line, Measurements for Dimethyl Isophthalate, Dimethyl Carbonate, 1,3,5-Triethylbenzene, Pentafluorophenol, 4-tert-Butylcatechol, α-Methylstyrene, and N,N‘-Bis(2-hydroxyethyl)ethylenediamine

This paper reports measurements made for DIPPR Research Project 821 in the 1993 Project Year. Vapor pressures were measured to a pressure limit of 270 kPa or lower decomposition point for all seven compounds using a twin ebulliometric system and, for dimethyl isophthalate and N,N‘-bis(2-hydroxyethyl)ethylenediamine, additionally an inclined-piston apparatus. Liquid-phase densities along the saturation line were measured for each compound over a range of temperature (ambient to a maximum of 548 K). A differential scanning calorimeter (DSC) was used to measure two-phase (liquid + vapor) heat capacities for each compound in the temperature region ambient to the critical temperature or lower decomposition point. Where possible, the critical temperature and critical density for each compound were determined experimentally. The results of the measurements were combined to derive a series of thermophysical properties including critical temperature, critical density, critical pressure, acentric factor, enthalpies...
Developmental aspects of 2‐way shuttlebox avoidance in the spontaneously hypertensive and normotensive rat

In experiment I, male and female rats from the spontaneously hypertensive (SHR) and Wistar-Kyoto (WKYN) normotensive strains were given I session of 2-way shuttlebox avoidance training at 25-26, 35-36, or 45-46 days of age. The avoidance training was preceded by a pretest which consisted of 10 presentations of the compound conditional stimulus alone in order to assess any differential tendency of the 2 strains to respond to the presentation of novel stimuli. The WKYN rats made a significantly higher number of pretest avoidance responses and achieved a higher level of avoidance performance than SHR rats. In addition, during the pretest, WKYN rats were more active and had a shorter 1st trial latency. In Experiment II, the pretest phase was replicated with a manipulation of the intensity of the auditory cue. Although the WKYN rats had a higher rate of pretest avoidance than SHR rats, the rate of pretest avoidances increased with intensity in both strains. The WKYN rats had a shorter 1st trial latency and a shorter median latency for the 10 trials and were more active that SHR rats during the pretest. These results relate to age-independent behavioral characteristics of these strains and the question of reactivity to environmental stimulation.
Maximum Likelihood Estimation with Incomplete Multinomial Data

Abstract When sampling from a multinomial population, it may happen either by chance or by design that some of the observations are only partially classified. In this article the amount of information in the partially classified observation is evaluated, and maximum likelihood estimators are obtained using both completely classified and partially classified data. In general an iterative solution is required, but special cases are identified in which the solution is obtained in closed form.
Increasing Incidence of Melanoma Among Young Adults: An Epidemiological Study in Olmsted County, Minnesota

Objective To identify the change in the incidence of cutaneous melanoma over time among young adults.
Effects of distribution of bulk density and moisture content on shrub fires

Formulation of a physics-based model, capable of predicting fire spread through a single elevated crown-like shrub, is described in detail. Predictions from the model, obtained by numerical solutions to governing equations of fluid dynamics, combustion, heat transfer and thermal degradation of solid fuel, are found to be in fairly good agreement with experimental results. In this study we utilise the physics-based model to explore the importance of two parameters – the spatial variation of solid fuel bulk density and the solid fuel moisture content – on the burning of an isolated shrub in quiescent atmosphere. The results suggest that vertical fire spread rate within an isolated shrub and the time to initiate ignition within the crown are two global parameters significantly affected when the spatial variation of the bulk density or the variation of fuel moisture content is taken into account. The amount of fuel burnt is another parameter affected by varying fuel moisture content, especially in the cases of fire propagating through solid fuel with moisture content exceeding 40%. The specific mechanisms responsible for the reduction in propagation speed in the presence of higher bulk densities and moisture content are identified.
Caudal fin locomotion in ray-finned fishes: historical and functional analyses

SYNOPSIS. Over the last 20 years, considerable progress has been made in quantifying the movement of the body during locomotion by aquatic vertebrates, and in defining the role of axial musculature in producing these kinematic patterns. Relatively little is known, however, about how specific internal structural features of the axial system in fishes affect body kinematics, and how such structural and functional features have changed during evolution. The major theme of this paper is that historical, phylogenetic patterns in the axial musculoskeletal system need to be integrated with experimental and functional data in order to understand the design of the locomotor apparatus in vertebrates. To illustrate this proposition, the evolution of the tail in ray-finned fishes is presented as a case study in phylogenetic and functional analysis of the vertebrate axial musculoskeletal system. Traditionally, the evolution of the tail in ray-finned fishes has been viewed as a transformation from a primitively heterocercal (functionally asymmetrical) tail to a homocercal tail in which the axis of rotation during locomotion was vertical, generating a symmetrical thrust. Both phylogenetic and functional approaches are used to examine this hypothesis. Major osteological and myological features of the tail in ray-finned fishes are mapped onto a phylogeny of ray-finned fishes to discern historical sequences of morphological change in the axial musculoskeletal system. A key event in locomotor evolution was the origin of the hypochordal longitudinalis muscle, the only intrinsic caudal muscle with a line of action at an appreciable angle to the body axis. This muscle originated prior to the origin of a caudal skeleton bearing both hypaxial and epaxial fin ray supports. The hypochordal muscle is proposed to be a key component of the axial musculoskeletal system that allows most fishes to modulate caudal function and decouples external morphological symmetry from functional symmetry. Experimental data (strain gauge recordings from tail bones, and electromyographic recordings from intrinsic and extrinsic caudal muscles) corroborate this interpretation and suggest that functional symmetry in the tail of ray-finned fishes is not predictable from skeletal morphology alone, but depends on the activity of the hypochordal longitudinalis muscle and on locomotor mode. The homocercal teleost tail may thus function asymmetrically.
Teaching Clinical Interviewing in the Health Professions A Review of Empirical Research

Empirical research on the teaching of interview skills has consistently shown significant (at p≤.05 level) changes on cognitive tests, affective measures, and observational data for students of various programs in the health professions. Most studies were simply comparisons of stu dents' pretest and posttest scores, with little control over possible confounding factors. Relatively few studies have in cluded direct comparisons of alternative approaches to the teaching of interview skills. These studies are examined in de tail, and trends among them are noted for the design of instructional programs. Also noted are the implications of these studies for future research.
A Critical Look at Physical Education and What Must Be Done to Address Obesity Issues

(2011). A Critical Look at Physical Education and What Must Be Done to Address Obesity Issues. Journal of Physical Education, Recreation & Dance: Vol. 82, No. 4, pp. 39-46.
NICE guidance on health technologies and the role of editors

The National Institute for Health and Care Excellence (NICE) is the independent organisation in England responsible for developing national guidance, standards, and information on providing high-quality health and social care, and preventing and treating ill health. Editing plays a major role in this process, by helping to ensure that published guidance from NICE lacks mistakes, omissions, and ambiguities and that it is easy to understand for both healthcare professionals and the public.
Binding of d-tubocurarine and α-bungarotoxin in normal and denervated mouse muscles

Abstract The action of native and mono- 3 H-acetylated-α-bungarotoxin ( 3 H-BuTX) was studied at the acetylcholine (ACh) receptors of innervated and of chronically denervated diaphragm and soleus muscles of the mouse. The 3 H-BuTX was similar in potency to the native toxin, and both toxins produced complete blockade of endplate potentials of innervated muscles and of ACh sensitivity of chronically denervated muscles. When the innervated muscles were washed for 4–7 hr after exposure to either toxin (at 1–5 μg/ml), recovery to an endplate potential value of 0.5–1 mV was recorded in most of the endplate regions of the surface fibers. Parallel experiments on the chronically denervated muscle after a 4–7 hr wash showed a much larger fraction of reversibility; i.e., while in control denervated preparations the ACh sensitivity was 50–75 mV/nC, after the toxin treatment and washing the values were 5–10 mV/nC. When d -tubocurarine ( d -TC, 28 × 10 −6 m ) was present to protect against the blockade of the toxin at the endplates, a complete recovery of neuromuscular transmission could always be obtained upon washing. In the chronically denervated muscles, however, much less protection from the 3 H-BuTX blockade was observed. Uptake of 3 H-BuTX at the endplates was measured by radioactivity analyses; these revealed that only about 60% of the endplate ACh receptors are protected at saturating d -TC levels. Kinetic analyses of the uptake confirmed this. The observations can be interpreted in terms of two types of sites at the endplate; the two are equally reactive with α-bungarotoxin, but only one of them binds d -TC firmly. Similar observations were made with d -TC protection in the denervated muscles; the results showed much lower affinity of d -TC in these muscles. The changes in d -TC effectiveness in the receptors after denervation are all parallel, when measured in several muscles by three approaches—blockade of ACh sensitivity, prevention of α-bungarotoxin blockade of ACh sensitivity, and inhibition of uptake of 3 H-BuTX. We conclude that the ACh receptor molecules themselves, when induced by denervation, are different from normal receptors in that they interact much less strongly with d -TC.
Kaposi's sarcoma in the hand of an AIDS patient

A case of Kaposi's sarcoma of a digit in a patient with acquired immune deficiency syndrome (AIDS) is described. The patient had what appeared to be a chronic paronychia. The paronychia tissue was excised and biopsy findings showed Kaposi's sarcoma. Kaposi's sarcoma is a multicentric, malignant, vascular tumor composed of proliferating spindle-shaped cells and capillary vessels.
Through the Looking Glass: A Personal View of the Field of Rehabilitation Medicine. The 56th John Stanley Coulter Memorial Lecture

Abstract Grabois M. Through the looking glass: a personal view of the field of rehabilitation medicine. The 56th John Stanley Coulter Memorial Lecture. This lectureship reviews the past, present, and future of the field of physical medicine and rehabilitation (PM&R) from the clinical, educational, and research points of view. I make recommendations for the field on how members of the various PM&R associations can make a difference in mapping the future.
The accuracy of the in vivo diagnosis of deep vein thrombosis in patients with prior venous thromboembolic disease or severe varicose veins.

Abstract Radiographic phlebography is the diagnostic standard for the detection of deep vein thrombosis in vivo . However, in patients with prior venous thromboembolic disease or severe varicose veins, ambiguity may exist in the interpretation of the phlebographic findings. To determine the accuracy of the diagnosis in the interpretation of a given phlebogram in a population of such patients, one hundred nine limbs in sixty-seven patients over age thirty-nine who had a history of venous thromboembolic disease or had severe varicose veins and who were undergoing total hip replacement were studied by both preoperative and postoperative radiographic phlebography. In addition, all limbs were studied using the fibrinogen uptake test and in sixty-two limbs by cuff impedance phlebography also. The postoperative radiographic phlebogram alone, the fibrinogen uptake test, the cuff impedance phlebography and various combinations thereof were compared to the accuracy provided by comparison of each set of pre- and postoperative phlebograms. In this group of patients, ambiguous findings on the postoperative phlebogram existed in 33% of the limbs. The combination of the fibrinogen uptake test with the postoperative radiographic phlebogram gave a sensitivity of 97% (32/33) and a specificity of 93% (71/76). Overall diagnostic accuracy (giving the correct result for each limb) was 94% (103/109 limbs).
The effect of capping H-2 antigens on the susceptibility of target cells to humoral and T cell-mediated lysis.

The cell-mediated immune response following grafting of allogeneic tissue is characterised by the development of cytolytically active, thymus-derived (T) lymphocytes, which are involved in the destruction of grafted tissue. These effector T cells also destroy homologous alloantigen-bearing (‘target’) cells in vitro. The specificity of the lytic process is exquisite; only cells of the graft donor or of a related strain or individual are destroyed1, 2. The precise nature of the alloantigens against which the lymphocytes act remains, however, unknown.
Visual Transitions as Therapy

AbstractThe present study describes a multimodal art therapy procedure using photography, art, movement, video and verbal discussion, Visual Transitions, and attempts to provide a theoretical rationale for the procedure as well as statistical evidence for its effectiveness. A group of volunteers took part in a seven-week program and filled out questionnaires before and after the experience. The Adjective Check List, the Personal Orientation Inventory, and a self-report critique show moderate but positive results for the program. The results are discussed and suggestions for future research are offered.
Learning Contexts, Black Cultural Ethos, and the Science Achievement of African American Students in an Urban Middle School.

As other countries vigorously promote rapid advancement in science, optimizing the participation of all students in the United States in science is imperative. This study focused on African American students and examined their science achievement in relation to Black Cultural Ethos (BCE), a construct rooted in psychology. Via qualitative and quantitative data obtained from a non-random control group design, the study addressed three questions: (1) With respect to BCE, what characterizes the natural instructional contexts of two middle school science teachers? (2) What characterizes the achievement of African American students in contexts that incorporate BCE and contexts that do not? (3) What achievement patterns, if any, exist in BCE and non-BCE instructional contexts? With regard to the natural contexts, the teachers did not incorporate BCE even when the opportunities were available to do so. Within these non-BCE contexts, the group's mean scores on the study-specific test that aligned with instruction decreased from pretest to posttest with approximately one-third of the students' scores improving. When a context was altered with a moderate effect size of 0.47 to include BCE, the group's mean scores on the aforementioned test increased from pretest to posttest with two-thirds of the students' scores improving. An illustration of the interplay between BCE and context and a consideration of the interplay as a mediating factor in research involving African American students encapsulate the significance and implications of the study's findings. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 665–683, 2008
Size-Resolved Source Apportionment of Airborne Particle Mass in a Roadside Environment

Airborne particulate hopanes, steranes, and polycyclic aromatic hydrocarbons (PAHs) were measured in six size fractions <1.8 µm particle diameter at one site upwind and two sites downwind of the Interstate 5 freeway in San Diego, CA. The smallest size fraction collected was exclusively in the ultrafine size range (Dp < 0.1 µm; PM0.1). Size distributions of hopanes, steranes, and PAHs peaked between 0.10-0.18 µm particle aerodynamic diameter with a tail extending into the PM0.1 size range. This pattern is similar to previous dynamometer studies of hopane, sterane, and PAH size distributions emitted from gasoline- and diesel-powered vehicles. Size-resolved source profiles were combined to form an “on-road” profile for motor oil, diesel, and gasoline contributions to EC and OC. The resulting equations were used to predict source contributions to the size distributions of EC and OC in the roadside environment. The method successfully accounted for the majority of the carbonaceous material in particles with diameter <0.18 µm, with significant residual material in larger size fractions. The peak in both the measured and predicted EC size distribution occurred between 0.1-0.18 µm particle aerodynamic diameter. The predicted OC size distribution peaked between 0.1-0.18 µm particle diameter, but the measured OC size distribution peaked between 0.56-1.0 µm particle diameter, possibly because of secondary organic aerosol formation. Predicted OC concentrations in particles with diameter <0.18 µm were greater than measured values 18 m downwind of the roadway but showed good agreement 37 m downwind. The largest source contributions to the PM0.1 and PM0.18 size fractions were different. PM0.18 was dominated by diesel fuel and motor oil combustion products while PM0.1 was dominated by diesel fuel and gasoline fuel combustion products. Total source contributions to ultrafine (PM0.1) EC concentrations 37 m downwind of the roadway were 44 ± 6% diesel fuel, 21 ± 1% gasoline, 5 ± 6% motor oil, and 30% unknown. Total source contributions to ultrafine (PM0.1) OC concentrations 37 m downwind of the roadway were 46 ± 5% diesel fuel, 44 ± 5% gasoline, 20 ± 15% motor oil with a slight overprediction (11%). Diesel fuel appears to make the single largest contribution to ultrafine (PM0.1) particle mass given the fleet distribution during the current experiment.
Stability and instability of solutions of semilinear problems

For two point problems, and for balls in R 2, we show how stability or instability of solutions can often be determined, when one knows just the maximum value of solution. As an application, we obtain various multiplicity results.
Response of Phaseolus vulgaris L. to differing ozone regimes having identical total exposure

Abstract Protocols were designed to test for differences in response of plants to ozone treatments having equal total exposure (concentration × time) but different exposure profiles Kidney beans ( Phaseolus vulgaris L., cv. California Dark Red) were exposed to ozone in controlled fumigation chambers within a greenhouse Four different ozone exposure profiles were used, each having the same total cumulative exposure (SUM00) and the same 7, 12 and 24 h seasonal means. The three exposure profiles which incorporated peak concentrations more severely impacted response parameters compared to a steady-state profile which did not exceed the National Ambient Air Quality Standard. Significant differences were found in percent necrotic leaf area, number of pods and top dry weight between exposure profiles. In additional analyses, the response parameters were regressed against seasonal cumulative ozone concentrations raised to powers of 0.33 and from 0.5 to 4 in steps of 0.5 in order to increase effective weighting of the higher concentrations. Total dry weight and leaf necrosis were best fit with the sum of the squared concentrations ( n = 2) while number of pods was best fit by the summed concentrations to the 3.5 power ( n = 3.5). These analyses suggest the peak ozone concentrations are important in determining plant response.
Theoretical evaluation of methods for extracting retention factors and kinetic rate constants in liquid chromatography

A three-dimensional stochastic simulation is used to provide a detailed understanding of mass transfer processes in liquid chromatography. In this simulation, the migration of individual molecules is established through diffusion and laminar convection within the mobile phase. The molecules interact with the stationary phase by a partition (absorption) mechanism. For these studies, the column length, linear velocity, stationary-phase diffusion coefficient, interfacial mass transfer coefficient, and equilibrium constant are varied in a system with a homogeneous surface. Heterogeneous surfaces are also investigated by having multiple types of interaction sites that are equally or unequally distributed. For each simulation, the molecular distribution is examined and characterized at specified times or column lengths. Five individual methods are then applied to extract the thermodynamic and kinetic information for transport between the mobile and stationary phases. In the first method, all of the molecules are initially distributed in the mobile phase and the fraction remaining is monitored as a function of time. These simulation data are fit to a single exponential decay by nonlinear regression to determine the "true" retention factors and rate constants. The other methods rely on evaluating the shape of the zone profiles along the column. The statistical moments of the profiles are used to calculate the mean and the variance, which are related to the retention factors and the rate constants, respectively. The profiles are also fit to the exponentially modified Gaussian equation, the Giddings equation, and the Thomas equation. The fitting parameters from these equations are then used to calculate the retention factors and rate constants. Comparisons of the accuracy relative to the "true" retention factors and "true" rate constants, as well as the advantages and limitations of each method are discussed.
Modeling learning in brain stem and cerebellar sites responsible for VOR plasticity

A simple model of vestibuloocular reflex (VOR) function was used to analyze several hypotheses currently held concerning the characteristics of VOR plasticity. The network included a direct vestibular pathway and an indirect path via the cerebellum. An optimization analysis of this model suggests that regulation of brain stem sites is critical for the proper modification of VOR gain. A more physiologically plausible learning rule was also applied to this network. Analysis of these simulation results suggests that the preferred error correction signal controlling gain modification of the VOR is the direct output of the accessory optic system (AOS) to the vestibular nuclei vs. a signal relayed through the cerebellum via floccular Purkinje cells. The potential anatomical and physiological basis for this conclusion is discussed, in relation to our current understanding of the latency of the adapted VOR response.
Purification and stability of the multienzyme complex encoded in the arom gene cluster of Neurospora crassa.

Abstract An improved method is described for the purification of the arom multi-enzyme complex from Neurospora crassa. The product of purification is an aggregate of approximately 230 000 mol. wt having five enzyme activities which function in the common pathway in aromatic amoni acid biosynthesis. Conditions promoting dissociation of the enzyme complex has been determined. Alkaline pH values, storage in low ionic-strength buffers, and high temperature all promote dissociation. The aggregate fragments resulting from dissociation are quite labile and have not been thoroughly characterized. However, in all but one of the fragments observed 5-dehydroshikimate reductase (Shikimate: NADP+ oxidoreductase, EC 1.1.1.25) and 5-dehydroquinate dehydratase (5-dehydroquinate hydro-lyase, EC 4.2.1.10) activities are associated. These two activities have been found alone or in association with one of the three additional activities. A presumptive dimer of 3-enolpyruvylshikimic acid 5-phosphate synthelase has also been observed. To explain the variety of fragments observed, the minimum number of polypeptides present is postulated to be 4. Thus, the possibility that the 115 000 mol. wt subunits of the complex are single multifunctional polypeptide has been excluded.
Correlation of Atomic Force Microscopy Tapping Forces to Mechanical Properties of Lipid Membranes

There is considerable interest in measuring, with nanoscale spatial resolution, the physical properties of lipid membranes because of their role in the physiology of living systems. Due to its ability to nondestructively image surfaces in solution, tapping mode atomic force microscopy (TMAFM) has proven to be a useful technique for imaging lipid membranes. However, further information concerning the mechanical properties of surfaces is contained within the time-resolved tip/sample force interactions. The tapping forces can be recovered by taking the second derivative of the cantilever deflection signal and scaling by the effective mass of the cantilever; this technique is referred to as scanning probe acceleration microscopy. Herein, we describe how the maximum and minimum tapping forces change with surface mechanical properties. Furthermore, we demonstrate how these changes can be used to measure mechanical changes in lipid membranes containing cholesterol.Copyright © 2012 by ASME
Magnesium and Potassium Interrelationships Experimental and Clinical

1) Coexisting Mg and K deficiency may occur with greater frequency than has been previously appreciated. 2) Profound hypokalemia, or refractoriness to K repletion or coexisting hypokalemia and hypocalcemia should suggest the possibility of concurrent Mg and K depletion. 3) The identification and treatment of concurrent K and Mg depletion is especially important in patients with congestive heart failure because of problem of digitalis toxicity. 4) We believe that the role of magnesium in optimizing cardiac function remains to be elucidated, identification and treatment of coexisting Mg and K depletion will be facilitated by making serum Mg a routine electrolyte determination together with Na, K, CI, CO2.
Specificity and metal sensitivity of renal amino acid transport

Abstract 1. 1. This study describe some properties of amino acid transport systems at the peritubular cell membrane in rabbit kidneys, and compares them with characteristics of amino acid uptake at the luminal membrane. 2. 2. Mutual inhibition studies led to the conclusion that at least four separate systems are involved in transport of l -amino acids at the peritubular membrane. These four systems, defined on the basis of their substrate specificities mediate uptake, respectively, of (a) dicarboxylic amino acids, (b) phenylalanine, (c) alanine, serine, cysteine, glycine, and (d) basic amino acids. 3. 3. In their structural specificity peritubular systems resemble those responsible for amino acid reabsorption at the luminal cell membrane. In contrast to luminal transport of dicarboxylic compounds, however, their peritubular uptake is inhibited by low concentrations of Hg; movement of other amino acids is not affected. Similarly, a peritubular action of Cd was observed, specific for aspartic and glutamic acids.
Chlorinated Hydrocarbon Insecticides as Soil Treatments Against the Eye Gnat Hippelates Collusor (Townsend) in the Labortory

A procedure for screening residual insecticides applied to soil in the laboratory has been perfected. An evaluation of some of the chlorinated hydrocarbon insecticides commonly used in controlling other soil-inbabiting insect pests revealed the fact that a few of these have appreciable biological activity against the eye gnat, Hippelate. collusor (Townsend). These materials with a high degree of activity are Shell Compound SD-4402 (1,2,3,4,5,6,7,8,8-Octachloro-3a,4,7,7a- tetrahydro-4,7 -methanophthalan), DDT, and endrin. Shell Compound SD-4402 gave 98% reduction of the emerging gnats when applied at 2.5 pounds Actual material per 6-inch acre (1 acre surface area 6 inches deep). DDT at 18 pounds actual material per 6-inch acre gave 80% while endrin at 5 pounds actual material per 6-inch acre gave 80% reduction of the emerging eye gnats from the treated soil. Aldrin, dieldrin, heptachlor, lindane, Compound GC-1189 or Kepone® (1,2,3,5,6,7,8,9,10,10-Decachlorotetracyclo [5.2.1. 02,6.03,9,05,8] decan-4-one), toxaphene, and chlordane yielded poor results when applied at moderate dosages (4 to 20 lbs. per 6-inch acre). Granulated formulations of DDT, particularly the higher percentage formulations, were found to perform poorly as compared with spray applications. Upon aging for 3 months, the effectiveness of 20% and 35% granulated formulations on attapulgite granules increased somewhat but did not equal that of DDT sprays. Ten per cent granulated formulations manifested increased effectiveness on aging and proved to be as effective as sprays after 3 months' aging. The biological activity of aldrin and dieldrin decreased when these materials were aged in soil for 3 months; that of DDT and endrin remained the same. The activity of toxaphene increased upon aging for S months, but the overall activity of this chemical against the pest was very low.
An algebraic treatment of finite Markov chains

Abstract Simple and explicit formulas are presented for the n -step transition probabilities p ij ( n ) in finite Markov chains. Formulas are also obtained for the limiting probability distribution and the mean return time for irreducible ergodic finite chains. An example is given for illustration.
Enhancing Technical Communication: Contemporary Applications for Advance Organizers

The basic principles of advance organizers set down by David Ausubel have become among the most widely used methods of instruction in schools today, but this approach has been limited for the most part to classroom instruction in primary and secondary schools and has not seen widespread discussion and application in technical communication theory and practice. This presentation examines the concept of advance organizers, categorizes the different types of advance organizers - textual, oral, and graphical - then illustrates how professional communicators may use rich media product simulation software to expand these categories with second-generation advance organizers that provide multimodality, interactivity, and feedback to technical documents.
Design and Implementation of a Dual-Camera Wireless Sensor Network for Object Retrieval

This paper presents the design and implementation of a dual-camera sensor network that can be used as a memory assistant tool for assisted living. Our system performs energy-efficient object detection and recognition of commonly misplaced objects. The novelty in our approach is the ability to tradeoff between recognition accuracy and computational efficiency by employing a combination of low complexity but less precise color histogram-based image recognition together with more complex image recognition using SIFT descriptors. In addition, our system can seamlessly integrate feedback from the user to improve the robustness of object recognition. Experimental results reveal that our system is computation-efficient and adaptive to slow changes of environmental conditions.
Oxoverbrückte Polyeisenzentren in Biologie und Chemie

Proteines renfermant des centres «polyfer» pontes par l'oxygene. Noyaux «difer(III)» pontes par l'oxygene. Systemes «trifer(III)» pontes par l'oxygene. Complexes «oxo» tetranucleaires de fer(III). Complexes «oxo» polynucleaires de fer(III)
Coronal build-up of the degraded tooth before endodontic therapy.

Summary The importance of using the rubber dam in endodontic therapy has been well documented. There are conditions, however, which make it impossible to place and retain it securely. Many a salvageable tooth has been extracted for this reason alone. The method described in this paper has been efficient in creating a composite build-up on these problem teeth, with the help of a core form, thereby allowing an esthetic replacement of the coronal portion of the remaining tooth at the first appointment. It also prevents contamination during endodontic treatment.