cssi/SciSciGPT-SciSciNet huggingface dataset:
The Equivalent Circuit for a Plane Discontinuity in a Cylindrical Wave Guide

Impedance concepts in wave guides have been discussed rigorously and have been applied to the analysis of a plane discontinuity in the form of a junction between two guides of arbitrary cross sections separated by an infinitely thin diaphragm having arbitrary openings. The problem is described by a four-terminal network whose elements are given by the solution of an infinite number of simultaneous equations, any finite number of which may be solved to give a uniformly converging approximation to the true solution. In any specific application, it is merely necessary to substitute the characteristic eigenfunctions and eigenvalues in these equations without repeating their formulation. In many cases the analysis gives a lower bound to the true impedance, and in the case of a simple obstacle (no change of cross section) an alternative analysis is developed to yield an upper bound. The general equivalent circuit is represented as a T network, but it is shown that there is one important category of problems where this T section reduces to an ideal transformer plus a shunt element, which in turn may be reduced to a pure shunt element. The formulation of a pi network is discussed. The theory is applied to a transverse wire, capacitative and inductive windows, and capacitative and inductive changes of cross section in a rectangular guide, and approximate expressions for their impedances are deduced.
Semantic and surface codes in the memory of deaf children

Abstract In three experiments, deaf children in the age range of 6 years, 10 months to 15 years, 5 months were presented with continuous lists of items, and for each item they had to indicate whether it had appeared before on the list. Later items were related to preceding items either in surface form or in meaning or were unrelated. False-recognition errors (i.e., “yes” responses to new items) served as an index of memorial coding. In one experiment, the items presented to the subjects were printed words. The results of this experiment showed a false-recognition effect (i.e., more errors to related words than to unrelated words) for both semantically related words and orthographically similar words. In the other two experiments, the subjects viewed a series of manual signs on videotape. In these experiments, there was a false-recognition effect for signs related semantically and for signs related cherologically (i.e., similar in terms of their manual production). These results establish orthography and cherology as effective memorial codes for deaf children. The finding of a consistently strong semantic effect for young deaf children stands in contrast to findings of weak semantic effects in false-recognition studies with young hearing children. The ascendancy of semantic codes for deaf children was attributed to the absence of competition from the speech code which dominates the linguistic memory of hearing children.
Protein kinase C agonist and antagonist effects in normal human epidermal keratinocytes

Several lines of evidence implicate protein kinase C (PKC) in the development of basal cell and squamous cell carcinomas, tumors which originate from epidermal keratinocytes. To examine PKC in a model relevant to human skin, we exposed normal human epidermal keratinocytes (NHEK) in serum-free media to a variety of PKC agonists and antagonists. NHEK PKC activity increased up to 10-fold within the 1st hour of exposure to tetradecanoyl phorbol acetate (TPA), and gradually returned to control values within 72 h. TPA-induced PKC activity was enhanced by pretreatment of cultures with protein and RNA synthesis inhibitors. TPA-induced growth arrest and differentiation was antagonized by staurosporine. Down-regulation by bryostatin pretreatment blocked TPA-stimulated differentiation. Our overall conclusion is that activation of PKC in cultured human keratinocytes is required for differentiation. These results are crucial to the analysis of compounds suspected of promoting or inhibiting epidermal tumors.
Active uptake of MPP+, a metabolite of MPTP, by brain synaptosomes

Abstract Mouse brain synaptosomal preparations were used to study uptake of N-methyl-4-phenylpyridine (MPP + ), a metabolite of the neurotoxin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine). The uptake of [ 3 H]-MPP + by striatal synaptosomes was approximately 25 X greater than that of [ 3 H]-MPTP, with a K M of 0.48 μM and a V max of 5.3 nmoles/g tissue/min. Uptake was Na + dependent and inhibited by ouabain, cocaine and dopamine (K i 0.12 μM). Synaptosomes prepared from the corpus striatum accumulated [ 3 H]-MPP + at a rate 5–10 times higher than preparations from other brain regions. This selective uptake of MPP + may contribute to the specificity of the toxic effects of MPTP on nigrostriatal dopaminergic neurons.
The expected life of mobile homes

Abstract This article reports empirical evidence on the expected life of mobile homes. Three sources, using three different definitions of loss, are drawn upon: published studies, proprietary data from Foremost Insurance Company and Census data. The Census data are analyzed using logit analysis, and a life table for mobile homes is produced. Based on these analyses, implications are drawn for policy-makers and consumers, for the insurance, financing and manufactured housing industries, and for researchers.
Microwave ferrite materials and devices

The crystal structure of ferrites including garnets and their methods of preparation are first reviewed. This is followed by an examination of microwave ferrite devices and their application to actual systems. Sufficient theoretical details as well as an extensive though not exhaustive list of references are included for ready reference. The most widely used microwave ferrite device is the isolator, a device which possesses nonreciprocal properties. The function of this device in various configurations is therefore studied in some detail. Then, ferrite-phase shifters, including the latching variety, circulators, modulators, power limiters, switches, amplifiers, delay lines, and filters are examined in turn. Microwave ferrite devices, in particular isolators and circulators, are commonly used in the laboratory. Other devices, such as modulators, limiters, and switches, are used respectively in microwave systems in carrier modulation, receiver protection, and antenna switching, etc. Much of the ferrite device research and development in recent years has been concerned with the Y -junction circulator and the coincidence power limiter.
Growth factors and cytokines: Emphasis on their role in wound healing and atherosclerosis

Summary Growth factors and cytokines are the vital mediators of both normal physiological and pathophysiological processes. This review will highlight the contrasting effects of certain growth factors and cytokines involved in a normal physiological process such as wound healing and in a pathological condition such as atherosclerosis. In addition, this review will also discuss the future of these signalling molecules in wound healing and atherosclerosis research.
Giggle incontinence in children: a manifestation of detrusor instability.

ABSTRACTPurpose: To our knowledge the prevalence and cause of giggle incontinence in children is not known. We hypothesized that laughter may induce unstable detrusor contractions in children susceptible to detrusor instability. We evaluated the prevalence of diurnal voiding symptoms of urinary urgency, urge incontinence, pelvic withholding maneuvers and hesitancy in patients with giggle incontinence, the prevalence of giggle incontinence in patients with diurnal voiding symptoms, the prevalence of the 2 conditions in first degree relatives of patients with giggle incontinence, the influence of treatment for detrusor instability on the frequency of giggle incontinence and the prevalence of diurnal voiding symptoms in control children with giggle incontinence.Materials and Methods: Of 1,421 children 5 to 15 years old referred to the pediatric nephrology department for various problems 109 were diagnosed with giggle incontinence and 460 had diurnal voiding symptoms. A total of 627 children visiting the pedi...
Tadalafil-associated priapism

A healthy 46-year-old man presented to the Emergency Department with a 36-hour history of persistent, painful erection after taking the cyclic guanylyl monophosphate-specific phosphodiesterase 5 inhibitor tadalafil. He had no other identified contributing factors for priapism. After confirmation of ischemic priapism and failure of bedside management in the Emergency Department, the patient underwent operative caverno-spongiosal shunting. Postoperatively, the erection initially rebounded but gradually receded with manual compression over 48 hours. At outpatient follow-up, the patient remained flaccid without erections. To our knowledge, this is the first report of tadalafil-associated priapism.
Cartesian-closed coreflective subcategories of uniform spaces generated by classes of metric spaces

Abstract The main result, in Theorem 3, is that in the category Unif of Hausdorff uniform spaces and uniformly continuous maps, the coreflective hulls of the following classes are cartesian-closed: all metric spaces having no infinite uniform partition, all connected metric spaces, all bounded metric spaces, and all injective metric spaces. Furthermore, Theorems 1 and 4 imply that if C is any coreflective, cartesian-closed subcategory of Unif in which enough function space structures are finer than the uniformity of uniform convergence (as in the above examples), then either (1) C is a subclass of the locally fine spaces, or (2) C contains all injective metric spaces and C is a subclass of the coreflective hull of all uniform spaces having no infinite uniform partition.
Feedback control law generation for safety controller synthesis

In recent papers we have focused on the task of safety controller synthesis, that is, designing a controller that will take the system from any point within a compact set of initial states to a point inside a set of acceptable goal states, while never entering any state that is deemed unsafe. This method first finds a feedback controller that causes the system to be imbued with trajectory robustness, then finds open-loop reference signals that each safely drive the system from a subset of initial states to the goal state. In this paper we use piecewise affine system identification techniques to generate a feedback control law to replace the open-loop signals. This provides additional robustness to unexpected disturbances, in addition to reducing the memory required in the resulting controller, from storing many signals to a set of piecewise affine control laws.
Effects of adrenal steroid activator protein on the conversion of various 20- and 22-hydroxycholesterols to pregnenolone by adrenal mitochondrial enzymes

Abstract A heat-stable protein activator from bovine adrenal cortex mitochondria stimulates the conversion of cholesterol to pregnenolone in crude extracts of adrenal mitochondria, and resembles in some of its properties, the sterol carrier protein of liver (Kan et al . Biochem . Biophys . Res . Commun . 48 , 423–429, 1972). We have shown that activator preparations also stimulate highly purified adrenal enzyme preparations comprising four components: cytochrome P-450 specific for side chain cleavage, adrenodoxin, adrenodoxin reductase, and an NADPH-generating system. Furthermore, this activator stimulates the conversion not only of cholesterol, but also of (20S)-20-hydroxycholesterol, (22 R )-22-hydroxycholesterol, and (20 R , 22 R )-20,22-dihydroxycholesterol to pregnenolone. Our findings provide additional evidence that the steroid-activator complexes are the substrates for the side chain cleavage enzyme and that the monohydroxy and dihydroxycholesterols are true intermediates in the conversion of cholesterol to pregnenolone by bovine adrenal cortex mitochondria.
Electron microscopy of human skin fibroblasts in situ during growth in culture.

Abstract We have studied the electron microscopic (EM) appearance of cultured diploid human skin fibroblasts during logarithmic and confluent stages of growth using a simple technique which permits in situ visualization of individual cells in monolayer. By comparison, cells disrupted from a monolayer and pelleted showed drastic distortion of the cell surface and appearance of organelles: mechanical scraping produced massive dilatation of the rough endoplasmic reticulum (RER); and trypsin-produced multiple blebs of the plasma membrane and cytoplasmic vacuoles. In situ, these changes in trypsinized cells disappeared within 1 h after plating. Six hours later, microtubules and microfilaments had surrounded the nucleus and were oriented in longitudinal bundles beneath the plasma membrane during rapid growth. At confluence these cytoskeletal elements seemed to extend beyond the plasma membrane at intercellular junctions. Pinocytotic vesicles were abundant at those surfaces devoid of filaments. Mitochondria, aligned with the long axis of the cell, were extremely long and narrow. During logarithmic growth there were many free ribosomes, polysomes, and some flat cisternae of RER. At confluence most ribosomes were found in spirals on dilated saccules of RER which contained electron-dense material. Lysosomes of several types were present during all phases of growth and varied in number from cell to cell. Late in culture the lysosomes tended to be larger, often occupying whole areas of cytoplasm or even extruding from the cell, and resembled those seen in lysosomal storage diseases. Understanding the in situ ultrastructure of normal human fibroblasts during growth in culture will permit systematic examination of such cells in a variety of pathological states.
Reproductive physiology and human evolution

Abstract Reproductive function is one of the cornerstones of understanding the proximate mechanisms that have shaped human evolution. Moreover, reproductive function itself has been shaped by selective forces that have resulted in the physiology we see in contemporary populations. Consequently, it is impossible to completely understand reproductive function or health without a Darwinian perspective. In addition to an evolutionary perspective, life history theory, based on the well-founded assumption that all organisms often face energy allocation decisions between competing physiological needs such as growth, maintenance, and reproduction, is crucial for understanding the interactions between reproductive function and other aspects of physiology, some of which manifest in ways that can be interpreted as disease or illness. Both male and female reproductive physiologies are the result of selection for physiological mechanisms that optimally allocate energetic resources between central life history tradeoffs. However the selective forces on each sex are often unique, resulting from the differential metabolic costs of reproduction in mammalian species. In this discussion, the evolution and life history of human reproductive function will be examined in light of energetic constraints, male/female contrasts, known spectrum of human variation, as well as potential health ramifications.
Radiological studies of cerebrospinal fluid and hydrocephalus

In recent years several new radiological techniques have been used for the evaluation of patients with hydrocephalus and for the study of cerebrospinal fluid formation and absorption. Radiological methods have been developed in dogs to measure the rates of cerebrospinal fluid formation in various parts of the ventricular system. In carefldly controlled conditions the formation of fluid may be demonstrated in patients during pneumoencephalography. Computerized tomography is a safe and painless technique that may largely replace pneumoencephalography and ventriculography for diagnosis of hydrocephalus. Combined with intravenous contrast enhancement it often gives the neurosurgeon sufficient information to treat the patient without the need for angiography or pneumoencephalography. A new safer radiographic contrast agent, Metrizamide, may be introduced into the subarachnoid space for the study of hydrocephalus. This contrast material can then be demonstrated in the cranial cerebrospinal fluid by computerized tomography.
Testicular Asymmetry in the Turkey

Abstract Right and left testicular weights were obtained from immature and adult turkeys. The left testes were larger than the right in 90.9% of day old toms, in 94.3% of toms between the ages of 53–55 weeks and in 100.0% of toms 63–67 weeks of age. In all groups examined the mean left gonad weights were significantly larger than the right. In several individuals with larger right than left testes, the right was 3–4 times larger than the left.
The atmospheric chemistry of dimethylsulfoxide (DMSO) kinetics and mechanism of the OH + DMSO reaction

We have employed a pulsed laser photolysis-pulsed laser induced fluorescence technique to study the kinetics and mechanism of the reaction of OH with dimethylsulfoxide and its deuterated analogue. A rate coefficient of (1.0±0.3)×10-10 cm3 molecule-1 s-1 was obtained ar room temperature. The rate coefficient was independent of pressure over the range 25–700 Torr, showed no dependence on the nature of the buffer gas and showed no kinetic isotope effect. A limited study of the temperature dependence indicated that the reaction displays a negative activation energy. The gas phase ultraviolet absorption spectrum was obtained at room temperature and showed a strong absorption feature in the far ultraviolet. The absolute absorption cross-section at 205 nm, the absorption peak, is (1.0±0.3)×10-17 cm2, where the large uncertainty results from experimental difficulties associated with the low vapor pressure and ‘stickiness’ of DMSO.
Spatial and temporal responses of the maize catalases to low temperature

Catalase (H 2 O 2 :H 2 O 2 oxidoreductase, EC 1.11.1.6) is a primary antioxidant enzyme that can remove H 2 O 2 rapidly and prevent the formation of reactive oxygen species. The maize (Zea mays L.) catalase genes are regulated in their expression spatially and temporally. Using embryos from germinating seeds and developing kernels from the maize standard inbred line W64A, which expresses all three Cat genes, and the CAT-2 null line A338F, we have examined the response of the three catalase genes to low temperatures (14°C, 4°C, or 14/4°C). Total catalase activity increased in response to low temperatures in germinating embryos of both maize lines. Zymogram analysis showed that the increase in total catalase activity was due to accumulation of the CAT-I and CAT-2 isozymes in the scutella and embryonic axes of germinating embryos. In both lines, CAT-3 activity decreased in the embryonic axes of germinating embryos in response to low temperatures. The steady-state levels of Cat transcripts did not parallel the pattern of the corresponding catalase proteins, indicating the involvement of post-transcriptional control mechanisms. In contrast to germinating embryos and excepting an increase at 4°C in A338F, total catalase activity decreased in response to low temperatures in scutella of developing embryos of both lines. CAT-2 activity (in W64A) and CAT-3 activity (in A338F) decreased in response to low temperatures and their corresponding steady-state levels of mRNA also decreased. Only CAT-I activity increased dramatically at 4°C in A338F, but Catl transcript level did not change. Out data indicate that the three maize catalase genes respond differentially to low temperatures at two different developmental stages.
Convergence results in an associative memory model

Abstract This paper presents rigorous mathematical proofs for some observed convergence phenomena in an associative memory model introduced by Hopfield (based on Hebbian rules) for storing a number of random n-bit patterns. The capability of the model to correct a linear number of random errors in a bit pattern has been established earlier, but the existence of a large domain of attraction (correcting a linear number of arbitrary errors) has not been proved. We present proofs for the following: • • When m , the number of patterns stored, is less than n /(4 log n ) , the fundamental memories have a domain of attraction of radius ρn with ρ = 0.024 , and the algorithm converges in time O (log log n ) . • • When m = α n (with α small), all patterns within a distance ρn from a fundamental memory end up, in constant time, within a distance ϵn from the fundamental memory, where ϵ is about e −1/4α We also extend somewhat Newman's description of the “energy landscape,” and prove the existence of an exponential number of stable states (extraneous memories) with convergence properties similar to those of the fundamental memories.
Alterations in the corticomotor evoked potential following spinal cord ischemia.

Abstract A simple yet reliable model of spinal cord ischemia has been previously developed by inserting a Swan-Ganz catheter into the abdominal aorta of rabbits and inflating the balloon just inferior to the renal arteries. Recent investigations have shown that paraplegia is consistently reproduced if the balloon remains inflated for 20 min after loss of the N 3 component of the somatosensory evoked potential. Because of its high reliability, this model has been frequently and successfully used to determine the efficacy of pharmacological agents thought to provide protection against spinal cord ischemia. Results from the present report demonstrate that a similar degree of reliability can be achieved in this model for testing motor activity. A simple method of evoking highly reproducible motor potentials, that can be percutaneously recorded from the spinal cord in response to cortical stimulation, was developed. Predictable and repeatable changes in the configuration of the corticomotor evoked potential were found during spinal cord ischemia and reperfusion. With this added dimension of functional assessment, future applications of the current spinal cord ischemia model have been greatly expanded.
What laboratory tests are required for ambulatory surgery

Current recommendations from the 2002 ASA Task Force on Preanesthesia Evaluation are not specific to ambulatory surgery and are not based on strongly designed and adequately powered studies. Furthermore, although the ASA does not advocate routine testing or testing without indication, the guidelines for "selective" or "indicated" testing are unclear. As a result, preoperative testing in the United States is overused relative to the current ASA Task Force recommendations. Uncertainty regarding indications leads to wide variation in the use of preoperative testing across providers. There is evidence to suggest that current guidelines may recommend testing more than is necessary. Several studies reviewed in this article have shown that the elimination of routine testing and more selective use based on patient history and physical examination findings would decrease cost and increase patient satisfaction without detriment to patient care. Future studies should evaluate the effectiveness of testing in specific clinical situations, allowing for identification of clear conditions under which preoperative testing should be performed. This approach would allow the promulgation of clear guidelines, the development of which should involve surgeons (as members of a multidisciplinary team), anesthesiologists, and hospital administrators, together with governing bodies such as the ASA and American College of Surgeons that offer support for the dissemination and broad adoption of guidelines. In the future, studies should focus not only on identifying specific clinical situations whereby preoperative testing will be beneficial but also on determining current barriers to improving adherence to guidelines. Potential barriers include institutional policies for testing, physician reluctance to change practice, problems in communication between members involved in perioperative care, and legal consequences of not ordering preoperative tests. Identification of reasons for overuse of testing is the first step toward changing practice. Once clear guidelines are developed, the creation of preoperative clinics that centralize preoperative care, or promoting the use of clinical pathways and/or checklists for determining appropriate tests, may improve the adequate use of preoperative tests. It will be critical for quality improvement measures to include surgeons, anesthesiologists, hospital administrators, and governing bodies such as the ASA and American College of Surgeons to achieve success.
Signaling versus contingent contracts with costly turnover

Abstract Typical models of educational signaling assume firms are uncertain of worker ability. However, there are both theoretical and empirical problems with such models. In contrast, as in Salop and Salop [Quarterly Journal of Economics 90 (1976) 619], a model is considered in this paper in which individuals differ in the likelihood of quitting and firms are unaware of an individual’s quit propensity. Education signals one’s commitment to remain in a particular sector or occupation. Alternatively, firms may offer back-loaded wages (contingent contracts) that may avoid signaling. The analysis suggests too little signaling may occur because contingent contracts may not be socially preferable to signaling, and because individuals may prefer not to signal when signaling is efficient and contingent contracts are not chosen by firms.
Pumpless arteriovenous carbon dioxide removal: A novel simplified strategy for severe asthma in children

Status asthmaticus unresponsive to pharmacotherapy is conventionally managed with mechanical ventilation, which has its inherent challenges due to barotrauma, dynamic hyperinflation and autopositive end-expiratory pressure (auto-PEEP). Extracorporeal membrane oxygenation has been used as a last resort in respiratory failure due to refractory asthma; however, it entails many complications. In contrast, arteriovenous carbon dioxide removal (AVCO 2 R) is a novel strategy that has been shown to be highly effective in adults with acute respiratory failure. Only one pediatric case series of pediatric asthma managed with AVCO 2 R have been published so far. We herein report a case of severe asthma in a 9-year-old boy who developed severe hypercapnia (Pco2 97 mmHg) and acidosis (pH 7.09) despite being on mechanical ventilation. Within 4 h of initiation of AVCO 2 R, PCo 2 drastically reduced to near-normal levels. He was discharged on day 9 of hospital stay without any complications.
Polyurethane networks based on poly(ethylene ether carbonate) diols

Abstract Ethylene carbonate was bulk-polymerized via a ring-opening mechanism using monoethylene glycol (MEG) as initiator and sodium stannate trihydrate as heterogeneous catalyst. Due to the loss of CO2 from a fraction of the repeat units during polymerization, a copolymer comprised of ethylene oxide and ethylene carbonate repeat units, poly (ethylene ether carbonate) (PEEC) resulted. The purified polymers were shown to be hydroxy-terminated by acetylation of the chain end and subsequent titration. Molecular weights higher than M n ∼ 4600 g mol −1 were not attainable due to a prevailing level of MEG present adventitiously in the system. PEEC-based polyurethane networks resulted from the reaction of four different molecular weight PEEC diols with a trifunctional isocyanate, triphenylmethane triisocyanate. Network characterization included equilibrium swelling, determination of sol content by solvent extraction, glass transition (Tg) by differential scanning calorimetry, and tensile properties by stress-strain measurements. A network curing schedule of 7 days produced networks with high sol contents (10%). Extension of the curing schedule to 19 days produced networks with low sol contents (2–5%) with the minimum sol content centred about a stoichiometric ratio, OH/NCO, of approximately one. Tensile strength ranged from 1.3 to 12.3 MPa, modulus ranged from 1.5 to 26 MPa, and strain at break ranged from 60 to 240 for networks from PEECs of M n in the range of 730–4400 g mol−1. Tensile properties, Tgs and equilibrium swelling measurements indicated that at increased isocyanate content the crosslink density of the network increased, possibly due to side reactions such as isocyanurate or allophanate formation.
The transcriptomics of de novo androgen biosynthesis in prostate cancer cells following androgen reduction

The progression of prostate cancer to the castration-recurrent phenotype remains a major problem medically. The present study examined the transcriptomics of de novo androgen synthesis as a potent...
Psychometric properties and podiatric medical student perceptions of USMLE-style items in a general anatomy course.

Background: In 2010, the New York College of Podiatric Medicine general anatomy course was redesigned to emphasize clinical anatomy. Over a 2-year period, United States Medical Licensing Examination (USMLE)–style items were used in lecture assessments with two cohorts of students (N =200). Items were single-best-answer and extended-matching formats. Psychometric properties of items and assessments were evaluated, and anonymous student post-course surveys were administered. Methods: Mean grades for each assessment were recorded over time and compared between cohorts using analysis of variance. Correlational analyses were used to investigate the relationship between final course grades and lecture examinations. Post-course survey response rates for the cohorts were 71 of 97 (73%) and 81 of 103 (79%). Results: The USMLE-style items had strong psychometric properties. Point biserial correlations were 0.20 and greater, and the range of students answering the items correctly was 25% to 75%. Examinations were hi...
What is Relevant? Student Perceptions of Relevance Strategies in College Classrooms

The operationalization of relevance has been problematic, raising concerns about the conceptualization of relevance. The current study inductively examined relevance by asking college students to generate relevance-increasing strategies used by instructors. Responses were grouped into five categories: “Outside Course Relevance,” “Methods and Activities Relevance,” “Teaching Styles Relevance,” “Inside Course Relevance,” and “No Relevance.” The results support previous relevance-increasing strategies suggested by Keller (1983) but also suggest that relevance may be an outcome of teacher behaviors, rather than a predictor of motivation.
Pediatrics: Acute kidney injury leads to pediatric patient mortality.

Data are lacking on the impact of acute kidney injury (AKI) in children admitted to an intensive care unit. Schneider and colleagues have now performed a large-scale assessment of the use of the RIFLE criteria for characterizing AKI in children and have determined the mortality and morbidity associated with AKI in this patient group.
Microstructural Modeling of Electrical Behavior in CNT Polymer Composites

A three-dimensional (3D) carbon nanotube (CNT) resistor network computational model was developed to investigate the electrical conductivity, and current and thermal flow in polymer composites with randomly dispersed CNTs. A search algorithm was developed to determine conductive paths for 3D CNT arrangements and to account for electron tunneling effects. By coupling Maxwell specialized finite-element (FE) formulation with Fermi-based tunneling resistance, specialized FE techniques were then used to obtain current density evolution for different CNT/polymer dispersions and tunneling distances. These computational approaches address the limitations of percolation theories that are used to estimate electrical conductivity of CNTs. The predictions indicate that tunneling distance significantly affects 3D electrical conductivity and thermal distributions.
Cambrian of the Grand Canyon--A Reevaluation: ABSTRACT

The Grand Canyon Cambrian, previously thought to represent a subtidal transgressive-regressive sequence recording deepening offshore accumulations of marine sandstone, shale, and limestone, is reinterpreted to record shallow-marine, tidal-flat, and fluvial sedimentation on the landward part of a vast cratonic platform marginal to the Cordilleran miogeosyncline. The basal Tapeats Sandstone is dominantly trough-crossbedded, contains no record of organic activity or marine-tracer grains, and displays a low-variance, unimodal paleocurrent trend down the paleoslope. This part of the Tapeats Sandstone records prevegetation, bed-load fluvial sedimentation. Shallow-marine "lagoonal" deposits dominate the rest of the sequence: burrowed, very thinly interbedded fine sandstones and shales (Bright Angel Shale) and arenaceous or soft-pellet limestones and dolomitic siltstones (Muav Limestone). Within the Bright Angel Shale, many 1-6 m thick units of burrowed, cross-laminated sandstone and glauconitic sandstone record shoaling sedimentation. These sandstones locally are succeeded by hematitic oolite beds which were exposure surfaces. Unburrowed, channeled, flaser-bedded sandstones form an extensive 20 m thick tidal-flat sequence in the western Grand Canyon. Within the Muav Limestone, 1-8 m thick units of dolomitized eocrinoidal biocalcarenite and algal-ball limestone, flat-pebble intraclast beds, and a few stromatolites emphasize the shoaling nature of the carbonate platform. A 20 m thick, dololaminite, End_Page 810------------------------------ tidal-flat unit locally interrupts the marine limestone sequence at the western (more offshore) end of the Grand Canyon. The 250-500 m Cambrian sequence appears to consist of more than 30 laterally persistent sedimentation cycles that are grouped into 5 grand cycles. The basal Tapeats Sandstone and the clastic and carbonate tidal flats are not cyclic. End_of_Article - Last_Page 811------------
Early Clinical Outcomes Using Proton Radiation for Children With Central Nervous System Atypical Teratoid Rhabdoid Tumors

Purpose Atypical teratoid/rhabdoid tumor (AT/RT) is an uncommon and aggressive tumor that often affects infants. Irradiation improves survival but has traditionally been avoided in patients under the age of 3 due to the increasing risk of neurocognitive side effects. We report the first cohort of AT/RT patients treated with proton therapy. Methods and Materials All patients with AT/RT treated at Massachusetts General Hospital (MGH) Frances H. Burr Proton Beam Therapy Benter between July 2004 and November 2011 were included in this study. All patients were treated with 3-dimensional conformal proton therapy (3D-CPT). Results Ten consecutive patients of a median 2.3 years of age and with a median follow-up of 27.3 months (range, 11.3-99.4 months) were identified. Two patients suffered distant relapse; 1 patient was successfully treated with involved field irradiation and chemotherapy, while the second patient died of disease. At last follow-up, 9 patients were alive without evidence of disease. Proton radiation demonstrated increasing sparing of the cerebrum, temporal lobe, cochlea, and hypothalamus. Conclusions Initial clinical outcomes with proton therapy are favorable. The advantages of proton therapy are particularly suited to the treatment of AT/RT, a tumor that often requires irradiation treatment at an age when avoiding irradiation to healthy tissues is most desirable.
Reasoning about the objects of attitudes and operators: towards a disquotation theory for representation of propositional content

S believes that P, S promises that P, S says that P, and so on are examples of sentences with embedded propositional content (that P in these examples.). Such sentences are ubiquitous in everyday reasoning, in legal reasoning, and in conducting business. This paper sketches an approach to formalizing such sentences for purposes of automated reasoning. The method advocated, called the disquotation theory of propositional content, applies to modeling formally propositional attitude sentences, as well as modal and deontic sentences. Exploiting the resources of event semantics, the method generates intensional contexts of the highest degree, then allows relaxations via added axioms.
AspectML: A polymorphic aspect-oriented functional programming language

This article defines AspectML, a typed functional, aspect-oriented programming language. The main contribution of AspectML is the seamless integration of polymorphism, run-time type analysis and aspect-oriented programming language features. In particular, AspectML allows programmers to define type-safe polymorphic advice using pointcuts constructed from a collection of polymorphic join points. AspectML also comes equipped with a type inference algorithm that conservatively extends Hindley--Milner type inference. To support first-class polymorphic point-cut designators, a crucial feature for developing aspect-oriented profiling or logging libraries, the algorithm blends the conventional Hindley--Milner type inference algorithm with a simple form of local type inference.We give our language operational meaning via a type-directed translation into an expressive type-safe intermediate language. Many complexities of the source language are eliminated in this translation, leading to a modular specification of its semantics. One of the novelties of the intermediate language is the definition of polymorphic labels for marking control-flow points. When a set of labels is assembled as a pointcut, the type of each label is an instance of the type of the pointcut.
Prospective clinical trial to compare vincristine and vinblastine in a COP-based protocol for lymphoma in cats.

Background Current standard chemotherapy protocols for lymphoma in cats carry risks of gastrointestinal toxicity, which can decrease quality of life and complicate response assessment. Protocols with less gastrointestinal toxicity may improve treatment tolerance. Hypothesis/Objectives The study purpose was to compare response rate, outcome, and toxicity between cats that received vincristine or vinblastine as part of combination chemotherapy for lymphoma. We hypothesized that vinblastine would have similar efficacy, but less gastrointestinal toxicity, compared with vincristine. Animals Forty client-owned cats with confirmed diagnosis of lymphoma. Methods Cats were randomized to 1 of 2 treatment arms and received weekly COP-based chemotherapy for 6 months or until disease progression. Response rate, progression-free survival (PFS), lymphoma-specific survival (LSS), and incidence and severity of gastrointestinal and hematologic toxicity were compared between arms. Arm cross-over occurred if specific gastrointestinal toxicity criteria were noted. Results Cats in both arms had similar response rates, PFS, and LSS (48 versus 64 days, P = .87; 139 versus 136 days, P = .96). Cats that received vincristine were significantly more likely to switch arms based on gastrointestinal toxicity than cats that received vinblastine (44.4 versus 10.5%, P = .02). Lower baseline weight was significantly negatively associated with PFS and LSS (P = .01, P = .003, respectively). Baseline anemia was significantly negatively associated with LSS (P = .04). Conclusions and Clinical Importance Results suggest that vinblastine is a reasonable alternative to vincristine in the treatment of some cats with lymphoma. Baseline body weight remains a significant prognostic factor for cats with lymphoma.
Comparative effects of clonidine and dihydroergotamine on venomotor tone and orthostatic tolerance in patients with severe hypoadrenergic orthostatic hypotension.

Abstract Purpose Clonidine, an α 2 -adrenergic agonist, raises blood pressure in patients with autonomic failure, in whom failure of reflex neurogenic venoconstriction leads to severe orthostatic hypotension. Because animal studies suggest that postjunctional α 2 -adrenoreceptors are located mainly on venous capacitance rather than arterial resistance vessels, we tested the hypothesis that venoconstriction is the main mechanism by which clonidine raises blood pressure in patients with autonomic failure. Subjects and methods We measured forearm venous and arterial tone using plethysmography in 4 patients with autonomic failure before and after acute administration of clonidine (0.4 mg orally) or dihydroergotamine (0.15 mg intravenously), a known venoconstrictor agent. We also recorded supine intraarterial pressure at rest and during graded orthostatic stress with lower body negative pressure. Results Clonidine and dihydroergotamine caused similar increases in supine (mean ± SD) arterial pressure (+23 ± 11 mm Hg vs. and +27 ± 5 mm Hg) and forearm vascular resistance (+36% ± 13% vs. +28% ± 9%). However, the drugs had different effects on forearm venous tone, which increased by 38% ± 9% with dihydroergotamine ( P = 0.01 vs. control) but was unaffected by clonidine (change = 0% ± 14%). A single dose of clonidine was less effective than a single dose of dihydroergotamine in maintaining arterial pressure during graded orthostatic stress. Conclusion In contrast with what has been hypothesized, clonidine appears to function mainly as an arterial constrictor in patients with hypoadrenergic orthostatic hypotension. Further studies are needed to determine if venoconstrictor agents are of greater therapeutic benefit in this condition than are pure arterial vasoconstrictors.
Virtual Prototype Simulation of Fine-Adjustment System Kinematics for Segment Erector of Tunnel Boring Machine

In this paper, we present the modeling and kinematics simulation of fine-adjustment system for segment erector of tunnel boring machine (TBM), which is performed in the virtual prototype platform. The 3D virtual assembling model of fine-adjustment system is built with Pro/E software according to its design parameters such as structure and size. After the interference inspection, the model is imported into ADAMS through the interface module of Mech/Pro. The model is simplified and optimized reasonably and various constraints are applied under variety working conditions. The results of simulation show that the design has three degrees of freedom movement capacity which meets the design requirements. At the same time the kinematics characteristics of each part along three different directions are obtained and they will provide some references for the further optimal design.
Those venerable notions.

Why in the world would a dental infection lead to a systemic defect in leukocyte function? In the article by Shurin et al. in this issue, we are confronted with two patients, one with a history of ...
Prospects for an AIDS vaccine

Several lines of evidence indicate that development of an effective vaccine for HIV-1 is going to be, at best, extremely difficult. The inability to solve fundamental scientific questions is the root cause for why a successful vaccine is not currently within our grasp. A renewed, organized, focused effort is needed to overcome these scientific obstacles.
Investigation of an energy-gap model for photoacoustic O2 A-band spectra: H2O calibration near 7180 cm−1

Abstract A photoacoustic spectrometer is used to evaluate the accuracy of an energy-gap model for collisional energy transfer. For photoacoustic measurements involving the b 1 Σ g + ← X 3 Σ g - transition of molecular oxygen the conversion of photon energy to thermal energy is inefficient and proceeds through the a1Δg state. This results in attenuation of the photoacoustic signal. The magnitude of the attenuation can be predicted with an energy-gap model whose accuracy has been previously confirmed to within 3 ± 5%. However, this prior result does not rule out incomplete rotational relaxation of O2 in the a1Δg state. In this study, high-resolution spectra of H2O in air are used to calibrate the photoacoustic spectrometer. This work binds the relative uncertainty in the energy-gap relaxation factor for O2 A-band photoacoustic signals to be approximately 1%. During one acoustic cycle, this result implies negligible collisional relaxation to the X 3 Σ g - state of O2 and nearly complete collisional relaxation to the a1Δg state.
Treatment evaluation issues in research on addictive behaviors

Abstract The growing development of treatment programs for addictive behaviors has not always been coupled with complete evaluations of these programs. General issues in treatment outcome methodology are relevant to addictive behaviors investigations. Necessary factors of internal and external validity are examined for establishing causal relations. The logic and advantages of both the within-subject and between-subject experimental designs are discussed. Assessment issues are presented which deal with reliability, validity, multiple dependent measures, symptom substitution, patient and therapist variables, and data analysis. Finally, criteria such as generalization, follow-up, standardized improvement indices, cost-effectiveness, and clinical significance are suggested as guidelines for evaluating treatment outcome.
Spaces with finitely generated cohomology

Abstract The main result of the paper is the following: Theorem. Suppose all the Cech cohomology groups of a space X are finitely generated and H m (X; Z ) is free for some m⩾2. There is a metrizable space Y∈Cm−1∩LC∞ and a map f :X→Y such that f ∗ :H k (Y; Z )→H k (X; Z ) is an isomorphism for all k⩾m. If dimX is finite or X is uniformly movable and H k (X; Z ) vanish for large k, then Y is a finite polyhedron.
Diagnosis of Atrial Tumors by Ultrasound

A rapid, harmless, noninvasive technic using ultrasound to diagnose intra-atrial mass lesions is described. The technic permits detection of those tumors which pass through the atrioventricular orifice. Two patients with left atrial myxomata and one with a right atrial myxoma were studied with pulsed, reflected ultrasound, cardiac catheterization, and cineangiography. The diagnosis in each case was confirmed at surgery. The ultrasound technic for detecting atrial tumors was based on recording a mass of echoes immediately behind the echoes originating from the mitral or tricuspid valve leaflets. The mass held the leaflet open during diastole, causing abnormal valve motion. In one case of left atrial myxoma, the tumor plop sound, clinically confused with an opening snap, was shown to occur at a different time in the ultrasound cycle than the true opening snap. This examination is simple enough to be considered as a screening examination for the detection or exclusion of this rare but potentially dangerous abnormality.
Copper in dental amalgams.

Summary The relationship between microstructure and physical and electro-chemical properties of copper-containing dental amalgams has been discussed in an attempt to understand the role of copper in currently used dental amalgams.