cssi/SciSciGPT-SciSciNet huggingface dataset:
Electrostatic channeling in P. falciparum DHFR-TS: Brownian dynamics and smoluchowski modeling

We perform Brownian dynamics simulations and Smoluchowski continuum modeling of the bifunctional Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (P. falciparum DHFR-TS) with the objective of understanding the electrostatic channeling of dihydrofolate generated at the TS active site to the DHFR active site. The results of Brownian dynamics simulations and Smoluchowski continuum modeling suggest that compared to Leishmania major DHFR-TS, P. falciparum DHFR-TS has a lower but significant electrostatic-mediated channeling efficiency (∼15–25%) at physiological pH (7.0) and ionic strength (150 mM). We also find that removing the electric charges from key basic residues located between the DHFR and TS active sites significantly reduces the channeling efficiency of P. falciparum DHFR-TS. Although several protozoan DHFR-TS enzymes are known to have similar tertiary and quaternary structure, subtle differences in structure, active-site geometry, and charge distribution appear to influence both electrostatic-mediated and proximity-based substrate channeling.
Implementing a Required Ethics Class for Students in Accounting: The Texas Experience

This paper describes a triangulated case study of the experiences and attitudes of educators in Texas regarding recent implementation of a three‐semester‐hour course in ethics as a prerequisite education requirement for CPA examination candidates. We present the results of (1) examining syllabi of courses on the Texas State Board of Public Accountancy (TSBPA)'s approved list as of January 2006; (2) two follow‐up surveys of course instructors; and (3) unstructured interviews of selected members and staff of the TSBPA. The purpose of this descriptive study is to gather information concerning the content and pedagogy in college and university ethics courses for CPA exam candidates in Texas. In addition, we report impressions of course instructors and TSBPA staff as to their course and implementation experiences. The results of this study may be useful to educators elsewhere who are attempting to design and implement future courses in ethics for accounting students. In addition, our findings might prove insig...
Municipal residency laws and local public budgets

Prior research has shown that residency laws increase the productivity of municipal employees, which tends to reduce per unit operating cost. However, this gain in efficiency appears to have been lost when one considers that public employee groups tend to be ‘high demanders’ who have a greater tendency to vote in local elections and to support expenditure increases (Bennett and Orzechowski, 1983). Our results tend to provide additional evidence to support the findings of previous studies that public employee groups tend to exert a disproportionate impact on local budgetary decisions.
Fall Meeting: Showcasing our members' achievements and building community

Amazing! Inspiring! Incomparable! These are words that describe AGU's Fall Meeting—the largest gathering of Earth and space scientists in the world. Every December for 45 years, scientists from around the globe have converged on the Fall Meeting in San Francisco, Calif. Excitement and enthusiasm pervade this unique annual event, where our members present their latest research and communicate its relevance to the great challenges that face society. Fall Meeting attendees can also survey the evolving panorama of geophysical research and hear firsthand about the latest pioneering advances in our understanding of the Earth and planetary system. It's an extraordinary opportunity to share, to learn, to network, and to renew old friendships; and it's one of the most important ways that we as a scholarly society advance our mission of promoting “discovery in Earth and space science for the benefit of humanity.”
Preabsorptive insulin release in bulimic women and chronic dieters

Abstract Preabsorptive insulin release was examined in bulimic women and in matched controls who diet. A palatable food was presented to subjects after an overnight fast and plasma insulin and glucose were measured at baseline, during presentation of the food and after it had been tasted. Food presentation and consumption were associated with significant elevations in plasma insulin levels prior to elevations in blood glucose, but not prior to actual tasting and consumption of the food. Insulin levels of bulimic and dieting women did not differ significantly at any time. The results indicate that when dietary restraint and body weight are controlled, bulimics do not display abnormal patterns of insulin release in response to foods
Talin phosphorylation by Cdk5 regulates Smurf1-mediated talin head ubiquitylation and cell migration

Cell migration is a dynamic process that requires temporal and spatial regulation of integrin activation and focal adhesion assembly/disassembly. Talin, an actin and beta-integrin tail-binding protein, is essential for integrin activation and focal adhesion formation. Calpain-mediated cleavage of talin has a key role in focal adhesion turnover; however, the talin head domain, one of the two cleavage products, stimulates integrin activation, localizes to focal adhesions and maintains cell edge protrusions, suggesting that other steps, downstream of talin proteolysis, are required for focal adhesion disassembly. Here we show that talin head binds Smurf1, an E3 ubiquitin ligase involved in cell polarity and migration, more tightly than full-length talin does and that this interaction leads to talin head ubiquitylation and degradation. We found that talin head is a substrate for Cdk5, a cyclin-dependent protein kinase that is essential for cell migration, synaptic transmission and cancer metastasis. Cdk5 phosphorylated talin head at Ser 425, inhibiting its binding to Smurf1, thus preventing talin head ubiquitylation and degradation. Expression of the mutant tal(S425A), which resists Cdk5 phosphorylation thereby increasing its susceptibility to Smurf1-mediated ubiqitylation, resulted in extensive focal adhesion turnover and inhibited cell migration. Thus, talin head produced by calpain-induced cleavage of talin is degraded through Smurf1-mediated ubiquitylation; moreover, phosphorylation by Cdk5 regulates the binding of Smurf1 to talin head, controlling talin head turnover, adhesion stability and ultimately, cell migration.
Persistent cervical lymphadenopathy in an adolescent with Epstein–Barr induced hemophagocytic syndrome: Manifestations of a rare but often fatal disease

Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) is a non-malignant proliferative disorder characterized by histiocytic proliferation and hemophagocytosis following Epstein-Barr virus infection. Though quite rare, this condition represents an often fatal disease primarily affecting the pediatric population. We discuss the case of an adolescent female who presented initially with persistent cervical lymphadenopathy and the typical findings of tonsillar hypertrophy, pharyngitis, and splenomegaly associated with infectious mononucleosis. This case study outlines the pathogenesis, common clinical findings, diagnostic criteria, and a review of the HLH-94 treatment protocol. Early recognition and treatment is emphasized because of the fulminant course of the disorder.
Architecture with photopolymerization

A brief summary of three-dimensional photopolymerization using visible light photoinitiators and polyfunctional acrylates is presented. The work is directed by an effort to build actual models, in real time, using laser-initiated photopolymerization in x, y layers of dimensional depth z
Grindability of alpha-case formed on cast titanium

The hardened alpha-case (α-case) layer inevitably forms on the surface of titanium castings when prepared by investment casting. Because the hardness of the α-case is incomparable to that of the interior structure, the perception exists that the α-case is difficult to remove during cutting, grinding and polishing. Grindability (ease of grinding) of cast cpTi and cast Ti-6Al-4V was evaluated by grinding cast specimens incrementally using a SiC abrasive wheel. The present study revealed that the presence of the brittle α-case with lower fracture toughness is beneficial in grinding titanium. The α-case on the ductile cpTi can be ground much easier than its bulk interior structure. In less ductile Ti-6Al-4V, the grinding rate is much higher than that of cpTi, and the α-case and its interior structure are at similar levels since the fracture toughness of its α-case and the bulk material is not large enough.
High-intensity turbulence measurements in a Taylor-Couette flow reactor

Turbulence-intensity measurements were made in a Taylor-Couette flow reactor consisting of two counter-rotating concentric cylinders designed for the purpose of studying turbulent premixed-flame propagation. In the annulus separating the two cylinders, a nearly homogeneous turbulent flow is generated. The intensities of turbulent velocity fluctuations in the annulus in both axial and circumferential directions were measured by using laser-Doppler velocimetry for a wide range of cylinder rotation rates, corresponding to low through high (120 cm/s) intensities relative to typical laminar flame speeds for lean methane-air mixtures. The experimental measurements indicate a linear relation between turbulence intensities and average cylinder surface speed and demonstrate the usefulness of the Taylor-Couette apparatus for studies of premixed-flame propagation in high-intensity turbulent flow.
Mediastinitis following Coronary Artery Bypass Surgery: A 3-Year Review

Twenty cases of mediastinitis after coronary artery bypass graft operations in 1985-1987 were reviewed to determine risk factors. Two distinct clusters with a methicillin-resistant Staphylococcus aureus (MRSA) strain occurred in 1986. One resident was exposed to six cases but to only 5 of 24 controls (P less than .008). Cultures of his nares in January and November 1986 revealed the same MRSA strain as that of the cases. An attempt to eradicate the resident's nasal carriage of MRSA in January 1986 failed; eradication of his carrier state was achieved only after treatment with mupirocin. In a case-control study examining patients exposed to the resident, a prolonged duration of surgery (P less than .05) and a preoperative albumin level of less than 3.0 g/dl (P less than .009) were associated with mediastinitis with this MRSA. For the other 14 mediastinitis patients, who were not exposed to the resident, a preoperative albumin level of less than 3.0 g/dl was also a risk factor (8/14 cases vs. 8/43 controls, P less than .009). Thus, this study suggests that it is important to follow MRSA disseminators and to recognize that preoperative serum albumin levels are a risk factor for mediastinitis.
Density Functional Theory calculations on the magnetic properties of the model tyrosine radical-histidine complex mimicking tyrosyl radical YD · in photosystem II

Results of Density Functional Theory (DFT) theoretical investigations, which use a model tyrosyl (Tyr) radical and tyrosyl-histidine (Tyr-His) complex to mimick the Y D · radical in Photosystem II (PSII) are presented and compared to experimental results from 15N Electron-Nuclear Double Resonance spectroscopy (ENDOR) studies of the τ nitrogen coupling from His-189 in the PSII Tyr-His complex. The DFT calculations are performed using an optimized geometry of the tyrosine radical and Tyr-His complex. The conformational space of the Tyr-His tandem is explored by varying the relative geometry of the two components; relevant parameters, such as the spin distribution on the phenoxy-ring carbons of the Tyr radical and the EPR hyperfine tensors, are calculated at each geometry and compared with the available experimental data. The isotropic 15N-ENDOR signal arising from spin delocalization on the His hydrogen-bonded to the PSII tyrosine radical is analyzed in terms of the DFT obtained parameters. The calculations of the g tensor using the Gauge Independent Atomic Orbital (GIAO) approach are presented and the influence of the geometry of the Tyr-His complex on the deviation of the g-tensor elements from the free electron values is discussed.
Homogeneously catalyzed formaldehyde condensation to carbohydrates: III. Concentration instabilities, nature of the catalyst, and mechanisms

Abstract The formose reaction, the homogeneously catalyzed condensation of formal dehyde to sugars, proceeds simultaneously with Cannizzaro and cross-Cannizzaro reactions. Reaction studies in a continuous stirred tank reactor have shown that rate instabilities are exhibited. There are temperature instabilities as well as concentration instabilities in calcium hydroxide catalyst, formaldehyde reactant, and hydroxyl ion. It is postulated that Ca(OH) + is the actual catalytic species for the formose system. A unifying mechanism is developed that uses observed rate phenomena to explain why almost any base, regardless of valence, is a catalyst for the formose and Cannizzaro reactions of formaldehyde. The mechanism postulates that reactions proceed from a common intermediate complexed species, and the selectivity for each reaction depends on the nature of the catalyst forming the carbohydrate complex. The catalytic mechanism explains the Lobry de Bruyn-van Eckenstein aldose-ketose rearrangements and mutarotations of sugars that also proceed in the system.
Sensory gating mechanisms of the thalamus.

The thalamus is an obligatory station through which nearly all sensory information must pass before reaching the cerebral cortex. One of the major functions of the thalamus is the selective control of the flow of sensory-motor information to the cerebral cortex during different states of the sleep-wake cycle and arousal, and is controlled through the actions of various neurotransmitter systems in the brainstem, hypothalamus, and cerebral cortex. Recent investigations have detailed the cellular mechanisms, including the role of GABAA and GABAB receptors, involved in the generation of both normal (e.g. spindle waves) and abnormal (e.g. generalized seizures) patterns of activity in thalamocortical circuits. In addition, in vivo investigations have also revealed that the dense projection from the cerebral cortex to the thalamus may synchronize thalamocortical activity in a manner useful for sensory analysis. Together, these data suggest that oscillations and synchronization are important for both normal and abnormal function in thalamocortical circuits.
Semantic processing can facilitate free recall in mildly retarded adolescents.

Abstract The efficacy of semantic processing in free recall was investigated in two experiments with EMR adolescents. In Experiment 1, they were taught to use one of two semantic strategies for memorizing a 15-word list. Compared with controls, neither strategy helped recall either in original learning or transfer. In Experiment 2, one of the semantic strategies, a story mnemonic, was investigated further. Rather than being taught to construct their own stories as in Experiment 1, subjects in Experiment 2 were provided with experimenter-composed stories. They showed better immediate recall and retention after 2 months than did nostrategy controls. However, about 1 year after original learning, the retention of experimental and control subjects no longer differed. Discussion focused on the story mnemonic's potential utility and the criteria for judging such potential, e.g., amount of facilitation, ease of training and performance of the strategy, and the degree of its generalizability.
Against Ethical Criticism

L'A. defend la tradition esthetique contre la critique ethique et didactique de la litterature d'imagination, selon laquelle la valeur morale de la litterature reside dans son influence diffuse sur la pensee et l'action. Examinant le contenu moral et ideologique des oeuvres litteraires a travers les critiques de M. Nussbaum et W. C. Booth, l'A. montre que l'enseignement tire de la lecture releve plus de l'emotion que de l'experience, participant de la connaissance de soi et du plaisir artisitique
Effects of Continuous Versus Intermittent Exercise, Obesity, and Gender on Growth Hormone Secretion

Context: Obesity attenuates spontaneous GH secretion and the GH response to exercise. Obese individuals often have low fitness levels, limiting their ability to complete a typical 30-min bout of continuous exercise. An alternative regimen in obese subjects may be shorter bouts of exercise interspersed throughout the day. Objective: The objective of the study was to examine whether intermittent and continuous exercise interventions evoke similar patterns of 24-h GH secretion and whether responses are attenuated in obese subjects or affected by gender. Design: This was a repeated-measures design in which each subject served as their own control. Setting: This study was conducted at the University of Virginia General Clinical Research Center. Subjects: Subjects were healthy nonobese (n = 15) and obese (n = 14) young adults. Interventions: Subjects were studied over 24 h at the General Clinical Research Center on three occasions: control, one 30-min bout of exercise, and three 10-min bouts of exercise. Main O...
Trade Competition and Route Development in Georgia and the Carolinas, 1740-1900

Abstract The “ideal-typical” sequence model of transportation development has been widely referenced, but its application outside of its original African context has not been well tested. A graphical analysis is employed to evaluate the utility of the concept in explanation of the evolution of the transportation network in the Piedmont and Coastal Plain sections of Georgia and the Carolinas from the mid-eighteenth century to the late nineteenth century. The historical geography of transport expansion in this area appears to support the general parameters of the ideal-typical sequence and provides useful material for instruction related to the national standards for geographic education.
Monte-Carlo calculations of cloud returns for ground-based and space-based LIDARS

A Monte-Carlo model is described which has been developed for calculation of multiply scattered LIDAR returns. Results are shown for the common problem selected by the MUSCLE (MUltiple SCattering LIDAR Experiments) group for intercomparison, which represents a typical ground-based cloud-sensing scenario. This is contrasted with returns from the same cloud sensed by a space-based LIDAR, where multiple-scattering effects are much greater. The magnitude of multiple-scattering effects is seen to be largely determined by the optical depth across the receiver field of view at the cloud.
The early events of infection with tobacco mosaic virus nucleic acid.

Abstract The early events of infection with strains U1 and U2 of tobacco mosaic virus, and the nucleic acids isolated therefrom, were compared in the local lesion host Nicotiana glutinosa. The technique used was to irradiate infective centers with ultraviolet light at different times after initiation of infection. Infective centers initiated by intact virus display an initial lag period during which no change in resistance to ultraviolet light occurs. This lag period is 2 1 2 ; hours for the U2 strain and 5 hours for the U1 strain. In contrast, infective centers caused by the nucleic acid isolated from these two strains behave alike and display little or no lag before they begin to increase in resistance to ultraviolet light. The conclusion is reached that when infection is initiated with the intact virus, the nucleic acid moiety of the virus is freed from the protein moiety soon after infection is established and before virus replication begins.
Wall-induced orientational order of a liquid crystal in the isotropic phase - an evanescent-wave-ellipsometry study.

Using an evanescent-wave ellipsometric technique, we have studied the wall-induced orientational order in the isotropic phase of ${4}^{\ensuremath{'}}\ensuremath{-}n\ensuremath{-}\mathrm{pentyl}\ensuremath{-}4\ensuremath{-}\mathrm{cyanobiphenyl}$ (5CB) at a silane-treated glass surface. Near the isotropic-nematic transition temperature ${T}_{\mathrm{NI}}$, a weak nematic layer appears at the interface with its thickness exhibiting a critical divergence as $T\ensuremath{\rightarrow}{T}_{\mathrm{NI}}$ according to ${(T\ensuremath{-}{T}_{\mathrm{NI}})}^{\ensuremath{-}0.5}$. This observed pretransitional behavior is qualitatively at variance with the existing theories.
Beyond 850 nm: progress at other wavelengths and implications from the standard

Born of necessity of application, the Vertical Cavity Surface Emitting Laser (VCSEL) is now found in nearly all optical networking systems based on standards such as the IEEE 802.3z and ANSI X3.t11. Reliability continues to be the hallmark of the technology, and the volume manufacturing aspects are now realized. While VCSEls satisfying optical networking standards continue to provide the highest volume applications, the advantages of the technology are beginning to enable novel optical equipment. This paper explores development of VCSELs at wavelengths from 650 to 850nm, and the commercial applications of these devices in both the data communications and optical sensing arenas. VCSELs operating at longer wavelengths are also being developed, but are not at a stage of commercialization to be discussed in this forum.
A possible relationship between the nephrotic syndrome and urinary schistosomiasis

Abstract 1. 1) Of 25 consecutive African subjects suffering from the nephrotic syndrome, 15 had urinary schistosomiasis and three the intestinal form, as judged by examination of the urine, a rectal biopsy and an intravenous pyelogram. 2. 2) In eight of the 15 patients with urinary schistosomiasis, the disease was severe, three having hydronephrosis. In two the hydronephrosis was bilateral and the clinical picture in each case is given. 3. 3) The possible relationship between nephrotic syndrome and schistosomiasis is discussed. 4. 4) Although the evidence produced is inconclusive, it is felt that it should be recorded, if only to draw attention to the possible effect, be it indirect, on the kidneys.
Prolactin receptor on dissociated mammary epithelial cells at different stages of development.

Abstract Properties of prolactin receptors were measured by monitoring [ 125 I]prolactin binding to specific receptor sites on collagenase-dissociated mammary epithelial cells of virgin, pregnant and lactating mice. On a Scatchard plot the data generated a straight line and the estimated dissociation constant ( K d) and number of receptor sites on lactating cells were 0.9 × 10 −9 and 1540 per cell. The [ 125 I]prolactin binding was inhibited in presence of unlabeled prolactin and other lactogenic polypeptide hormones, but not by nonlactogenic polypeptide hormones. The [ 125 I]prolactin binding was sensitive to pronase and trypsin but not to DNAase, RNAase and hyaluronidase. Scatchard plot analysis further showed that while the number of receptors on mammary cells was variable at different stages of endocrine regulated developmental changes of the gland, K d of the hormone-receptor complex generally remained similar. The high level of prolactin receptors on mammary cells of virgins was reduced during pregnancy and the lactating mammary cells showed a highly elevated level of prolactin receptors. The results demonstrate that specific prolactin receptors can be measured on collagenase dissociated mammary epithelial cells and this method permits a direct assessment of the number of receptors on a per cell basis rather than indirect estimates, based on average DNA or protein content of the tissue, composed of heterogeneous cell types.
Evaluating the impact of recovery density on augmented reality tracking

Natural feature tracking systems for augmented reality are highly accurate, but can suffer from lost tracking. When registration is lost, the system must be able to re-localize and recover tracking. Likewise, when a camera is new to a scene, it must be able to perform the related task of localization. Localization and re-localization can only be performed at certain points or when viewing particular objects or parts of the scene with a sufficient number and quality of recognizable features to allow for tracking recovery. We explore how the density of such recovery locations/poses influences the time it takes users to resume tracking. We focus our evaluation on two generalized techniques for localization: keyframe-based and model-based. For the keyframe-based approach we assume a constant collection rate for keyframes. We find that at practical collection rates, the task of localization to a previously acquired keyframe that is shown to the user does not become more time-consuming as the interval between keyframes increases. For a localization approach using model data, we consider a grid of points around the model at which localization is guaranteed to succeed. We find that the user interface is crucial to successful localization. Localization can occur quickly if users do not need to orient themselves to marked localization points. When users are forced to mentally register themselves with a map of the scene, localization quickly becomes impractical as the distance to the next localization point increases. We contend that our results will help future designers of localization techniques to better plan for the effects of their proposed solutions.
Realtime location privacy via mobility prediction: creating confusion at crossroads

Users face privacy risks when providing personal location data to untrusted location based services (LBSs). Many existing attempts to anonymize users have relied on suppressing information about users' locations. This suppression results in reduced functionality, including degraded spatial accuracy or the loss of realtime location updates. We propose anonymizing a user by camouflaging their current location with various predicted paths. This is akin to increasing the noise floor around the user. We believe this different approach provides many advantages. By allowing the user to keep all desired functionality while still protecting the user's privacy, we enable use of a broader class of LBSs. To demonstrate our proposal, we develop CacheCloak, a system that enables realtime anonymization of continuous location updates without any loss of accuracy. Data from a GIS-based traffic simulation in an urban environment shows that CacheCloak can anonymize users rapidly.
The Development of Durkheim's Social Realism

1. The reform that contained all other reforms 2. The subtlety of things 3. The perfection of personality 4. A l'ecole des choses 5. The yoke of necessity.
Computed tomography application to lumbar epidurography

The application of current-generation computed tomography scanning to lumbar epidurography has resulted in a better appreciation of epidural anatomy and improved ease of interpretation of non-ionic contrast material within the epidural space. The development of extended window width has greatly improved imaging of the more variable levels of attenuation encountered in contrast material within the epidural space. The procedure of distribution of contrast material by catheter technique via the sacral canal approach is described. The experience obtained on examination of 24 patients is discussed, along with the possible adjunctive and primary roles of this type of imaging in evaluation of the lumbar spine.
Internally Mixed Liquid Injector for Active Control of Atomization Process

This paper presents the results of an experimental study of an internally mixed liquid injector. In this type of injector, atomization is attained by injecting a small amount of air (i.e., of the order of 20% of the mass  ow rate of liquid) into a liquid stream within the injector. Since most of the energy for atomization is supplied to the liquid by the atomizing air, a signi cantly small pressure drop can produce very  ne spray with a small amount of atomizing air. The results presented in this paper suggest that the investigated injector could be used to control the  ow rate and spray characteristics independent of each other by simultaneously varying the supply pressure of the liquid and the atomizing air ow rate. The effect of elevated backpressure on the injector’s performance was also studied. It was found that the range of droplet sizes that could be obtained by the atomizer did not change when the pressure at the injector exit was increased. The preliminary results obtained in this paper suggest that a controlled version of the investigated injector may  nd applications in modern gas turbine engines.
Holocene Offset and Seismicity Along the Panamint Valley Fault Zone, Western Basin-And-Range Province, California

(Accepted for publication May 22, 1978) ABSTRACT: Smith, R.S.U., 1979. Holocene offset and seismicity along the Panamint Valley fault zone, western Basin-and-Range province, California. In: C.A. Whitten, R. Green and B.K. Meade (Editors), Recent Crustal Movements, 1977. Tectonophysics, 52: 411-415. Holocene right-slip along the central segment of the Panamint Valley totals 20 m and dip-slip is somewhat less. The most recent offset, about 2 m right-slip, probably occurred at least several hundred years ago. If a comparable amount of slip occurred during earlier earthquakes, mean seismic recurrence intervals would have been about 700-2500 years during the Holocene.
Griseofulvin and ketoconazole in the treatment of dermatophyte infections.

Teignes tondantes, mycoses ungueales et mycoses cutanees extensives ne peuvent habituellement pas etre traitees par un topique seul, mais necessitent le recours a un traitement systemique: soit de la griseofulvine, soit du lectoconazole. L'etude porte sur l'efficacite comparee de ces deux traitements
Assembly of trunk and limb blood vessels involves extensive migration and vasculogenesis of somite-derived angioblasts.

Vascular development requires the assembly of precursor cells into blood vessels, but how embryonic vessels are assembled is not well understood. To determine how vascular cells migrate and assemble into vessels of the trunk and limb, marked somite-derived angioblasts were followed in developing embryos. Injection of avian somites with the cell-tracker DiI showed that somite-derived angioblasts in unperturbed embryos migrated extensively and contributed to trunk and limb vessels. Mouse–avian chimeras with mouse presomitic mesoderm grafts had graft-derived endothelial cells in blood vessels at significant distances from the graft, indicating that mouse angioblasts migrated extensively in avian hosts. Mouse graft-derived endothelial cells were consistently found in trunk vessels, such as the perineural vascular plexus, the cardinal vein, and presumptive intersomitic vessels, as well as in vessels of the limb and kidney rudiment. This reproducible pattern of graft colonization suggests that avian vascular patterning cues for trunk and limb vessels are recognized by mammalian somitic angioblasts. Mouse–quail chimeras stained with both the quail vascular marker QH1 and the mouse vascular marker PECAM-1 had finely chimeric vessels, with graft-derived mouse cells interdigitated with quail vascular cells in most vascular beds colonized by graft cells. Thus, diverse trunk and limb blood vessels have endothelial cells that developed from migratory somitic angioblasts, and assembly of these vessels is likely to have a large vasculogenic component.
Down syndrome screening in an asian population using alpha-fetoprotein and free β-hcg: a report of the taiwan down syndrome screening group

Objective To evaluate whether the strategy of maternal serum screening for Down syndrome, using alpha-fetoprotein (AFP) and free β-hCG in combination with maternal age, a technique developed in western countries, is applicable to an Asian population. Methods Alpha-fetoprotein and β-hCG were measured in serum samples from 23 Down syndrome pregnancies and 1748 unaffected singleton Taiwanese (ethnically Chinese) pregnancies at 14–22 weeks' gestation. Gestational agespecific medians and a maternal weight correction formula were established for our own population. Likelihood ratio for Down syndrome pregnancies in relation to multiples of the median (MoM) levels of these analytes were derived from the overlapping gaussian frequency distribution curves for Down syndrome and unaffected pregnancies. Results The serum AFP and free β-hCG median MoM values of Down syndrome pregnancies were significantly abnormal in Asian subjects (0.77 and 2.91, respectively), and similar to those of affected pregnancies in white women. The median value of free β-hCG:AFP MoM ratio (2.97) in Down syndrome pregnancies was significantly higher than that of unaffected pregnancies (1.09). The mean maternal weight during the second trimester in pregnant Asian women (55.2 kg) was markedly lighter than that of white women. At a 5.8% false-positive rate, free β-hCG identified 47.8% of Down syndrome pregnancies (likelihood ratio 8.2), AFP detected only 13% of the cases (likelihood ratio 2.2), and free β-hCG:AFP MoM ratio detected 43.5% of the cases (likelihood ratio 7.4). By using a multivariate risk algorithm involving the combination of AFP, free β-hCG, and maternal age, 56.5% of Down syndrome cases could be detected with a 5.3% false-positive rate (likelihood ratio 10.7). Conclusion Maternal serum screening strategy using AFP and free β-hCG in combination with maternal age is feasible in the detection of fetal Down syndrome among Asian women.
Traumatic hematomas of the posterior fossa. A clinicopathological spectrum

Eight patients were found to have traumatic hematomas of the posterior fossa during a 6-year period. There were four patients with extradural hematomas, one patient with a subdural hematoma, and four patients with intracerebellar hematomas. In one patient, clinically significant hematomas were found both in the extradural space and in the cerebellum. Clinical or radiologic evidence of skull fracture was present in each case, and computed tomography scans were diagnostic of a posterior fossa hematoma in all cases. In six of the eight patients, there was clinical deterioration prior to surgical treatment, and in three cases, this was abrupt. All patients underwent suboccipital craniectomy. Six patients survived; four made a good recovery. Our experience indicates that early operation is usually indicated for these lesions.
How human immunodeficiency virus ravages the immune system

The immune system of individuals infected with human immunodeficiency virus is affected in two distinct ways: by loss of CD4+ cells and by loss of T-helper-cell function. Neither of these processes is yet fully understood. Research during 1991 that investigated the interaction between human immunodeficiency virus and the immune system has raised as many questions as it answered. Nevertheless, many of the issues raised are relevant to mechanisms responsible for the ravaging of the immune system by human immunodeficiency virus.
The Attraction to At-Will Employment in Utah Governments

Abstract This article explores the mindset among Utah politicians and public administrators regarding at-will employment and related personnel reforms. At-will employment status is expanding in some Utah governments, and little is known about why. A small but influential group of officials were interviewed in hopes of learning more about this. Findings reveal a wide variation in attitudes and understanding of what at-will employment entails. Many of those interviewed expressed a willingness to consider it, and others showed stoical acceptance of it as another emerging feature of public personnel policy.
The Pittsburgh insulin-dependent diabetes mellitus (IDDM) study. HLA antigens and haplotypes as risk factors for the development of IDDM in IDDM patients and their siblings

Abstract The relationships between HLA antigens, sex, age at diagnosis, season of onset and insulin-dependent diabetes mellitus (IDDM) were studied in a consecutive admissions series of newly-diagnosed IDDM patients at Children's Hospital of Pittsburgh. In agreement with the findings of others, the strongest positive associations between IDDM and HLA antigens were seen with DR3 and DR4 (odds ratios (OR) of 3.5 and 4.4, respectively), while a very strong negative association was observed with DR2 (OR of 0.1). Male patients were significantly more likely than female patients to possess DR3 while female patients were significantly more likely to be DR4 + . No consistent relationships were found between HLA antigens and either age at diagnosis or season of onset. Using a life table approach, the cumulative risk of IDDM by age 24 in HLA-identical siblings of IDDM patients was estimated to be 10.3%. This risk was significantly greater than the risks to either HLA-haploidentical siblings (2.2%) or to HLA-nonidentical siblings (1.0%), whose risks were not significantly different. B7 + HLA-identical siblings of patients appeared to be protected from the effects of HLA-identicality—their cumulative risk by age 24 was estimated to be only 2.3%.
Selected aspects of the development of methods for the analysis of drugs by high performance liquid chromatography

1. The successful analysis of drugs in biological fluids and other matrices by reversed phase high performance liquid chromatography (h.p.l.c.) relies upon the optimization of the chromatographic separation, the sample preparation and the post-column detection. Recent advances in the detection and derivatisation of exogenous substances are described elsewhere in this volume (Sternson 1986).2. This paper deals with selected aspects of the optimization of the chromatographic separation, concentrating on the theoretical basis and practical application of mobile phase selectivity in reversed phase ion-pair systems.3. In addition, recent advances in sample preparation techniques which permit the direct injection of biological fluids are discussed.
Zeroing in on the cold

Low Temperature Physics: An Introduction for Scientists and Engineers. By P. V. E. McClintock, D. Meredith and J. K. Wigmore. Blackie: 1992. Pp. 296. a£65.
Recognition imaging with a DNA aptamer.

We have used a DNA-aptamer tethered to an atomic force microscope probe to carry out recognition imaging of IgE molecules attached to a mica substrate. The recognition was efficient (∼90%) and specific, being blocked by injection of IgE molecules in solution, and not being interfered with by high concentrations of a second protein. The signal/noise ratio of the recognition signal was better than that obtained with antibodies, despite the fact that the average force required to break the aptamer-protein bonds was somewhat smaller.
Expression of hepatitis B virus surface and e antigen genes cloned in bovine papillomavirus vectors

Abstract Sequences of the hepatitis B virus (HBV) genome coding for the surface antigen (HBsAg), but lacking the regulatory (preS) sequences, were cloned into a bovine papillomavirus (BPV) vector consisting of the transforming 69% of the BPV genome (BPV69T), and transformed into mouse c 127 cells. Clones carrying HBV and BPV sequences in the same transcriptional orientation did not produce immunologically active HBsAg, while those with the opposite orientation produced and secreted HBsAg. RNA species of an HBsAg producer were 3400, 9600, 11000 and 18000 nucleotides long and hybridized with both HBV and BPV probes. Mouse cells (c127) transformed with the whole BPV genome (BPV-1) carrying both the HBsAg-coding sequences and the regulatory preS sequences of HBV DNA were stable and produced and secreted HBsAg 22 nm particles. These yielded 11500 and 12500 nucleotide RNA transcripts which also hybridized with both BPV and HBV DNA probes. BPV-1 carrying whole HBV DNA monomer or dimer genomes yielded transformants which initially produced HBsAg as well as HBV e antigen (HBeAg), but these were not stable. The hybrid genomes, with the exception of those carrying the HBV dimers, existed as multicopy plasmids (50–100 copies per cell) and often acquired new sequences.
SIGN RETROREFLECTIVITY: COMPARING RESULTS OF NIGHTTIME VISUAL INSPECTIONS WITH APPLICATION OF MINIMUM RETROREFLECTIVITY VALUES

In 1993, FHWA published research recommendations for minimum levels of retroreflectivity for traffic signs. These values were later revised in a 1998 FHWA report. The minimum values were developed as part of a process to add end-of-service life retroreflectivity values to the Manual on Uniform Traffic Control Devices. There have been few or no comparisons between the use of minimum retroreflectivity values to define end-of-service life and the results of typical nighttime visual inspections. Researchers at the Texas Transportation Institute conducted such an evaluation as part of a Texas Department of Transportation (TxDOT) sign workshop. In the evaluation, TxDOT sign crews evaluated 49 signs on an 8-km (5-mi) closed course. Each sign was rated as "acceptable," "marginal," or "unacceptable." Vehicle headlamp illuminance was also measured. The results of the evaluations were compared with the application of the FHWA minimum values. The results show that whereas one sign did not meet the low-speed FHWA mini...
Activation of the Wnt/planar cell polarity pathway is required for pericyte recruitment during pulmonary angiogenesis.

Pericytes are perivascular cells localized to capillaries that promote vessel maturation, and their absence can contribute to vessel loss. Whether impaired endothelial–pericyte interaction contributes to small vessel loss in pulmonary arterial hypertension (PAH) is unclear. Using 3G5-specific, immunoglobulin G–coated magnetic beads, we isolated pericytes from the lungs of healthy subjects and PAH patients, followed by lineage validation. PAH pericytes seeded with healthy pulmonary microvascular endothelial cells failed to associate with endothelial tubes, resulting in smaller vascular networks compared to those with healthy pericytes. After the demonstration of abnormal polarization toward endothelium via live-imaging and wound-healing studies, we screened PAH pericytes for abnormalities in the Wnt/planar cell polarity (PCP) pathway, which has been shown to regulate cell motility and polarity in the pulmonary vasculature. PAH pericytes had reduced expression of frizzled 7 (Fzd7) and cdc42, genes crucial for Wnt/PCP activation. With simultaneous knockdown of Fzd7 and cdc42 in healthy pericytes in vitro and in a murine model of angiogenesis, motility and polarization toward pulmonary microvascular endothelial cells were reduced, whereas with restoration of both genes in PAH pericytes, endothelial–pericyte association was improved, with larger vascular networks. These studies suggest that the motility and polarity of pericytes during pulmonary angiogenesis are regulated by Wnt/PCP activation, which can be targeted to prevent vessel loss in PAH.
A Computational Method for Determining Global Fuel-NO Rate Expressions. Part 1

Global chemical reaction rates used in the modeling of NOx formation in comprehensive combustion codes have traditionally been obtained through correlation of experimental data. In this paper, a computational approach for obtaining global rates is presented. Several premixed flames were simulated, and sensitivity analysis of species concentration profiles was used to suggest global pathways in fuel-nitrogen conversion to NO. Based on these analyses, the global reaction rates were formulated. The predicted species concentration profiles and their derivatives were then used in the determination of the global rate constants. The correlation of rate constants for the two fuel-NO global rates (HCN + NO → N2 + ... and HCN + O2 → NO + ...) are discussed. Comparisons of the computed global rate constants with those deduced from experimental data show good agreement. The global rates provide practical kinetics for simulating nitrogen pollutant chemistry in complex flames.
Chlorthalidone: mechanisms of action and effect on cardiovascular events.

How chlorthalidone (CTDN) reduces risk for cardiovascular events (CVEs) can be considered in light of its ability to lower blood pressure (BP) and its non-BP related, pleiotropic effects. The mechanism by which CTDN lowers BP is unclear but may include alterations in whole body regulation and vasodilatory actions on vasculature, possibly mediated via its inhibitory effects on carbonic anhydrase. Additionally, CTDN has potentially beneficial, non-BP related, pleiotropic effects that include improvements in endothelial function, anti-platelet activity, and oxidative status. CTDN reduces pulse wave velocity, predictor of CVEs and a measure of central aortic stiffness associated with endothelial dysfunction. On the other hand, CTDN fosters hypokalemia, hyperglycemia, sympathetic discharge, and the renin–angiotensin–aldosterone system, but these potentially harmful effects do not appear to materially reduce CTDN’s ability to prevent CVEs. Further, CTDN reduces and regresses left ventricular hypertrophy (LVH), an important BP-dependent predictor of CVEs. Consistent with this finding, CTDN was more effective than amlodipine in reducing congestive heart failure (CHF) in the Anti-hypertensive and Lipid-lowering Treatment to Prevent Heart Attach Trial (ALLHAT). In reducing CVEs, CTDN was superior to lisinopril in ALLHAT and superior to hydrochlorthiazide in observational cohort analyses and in network analyses of randomized trials. A statistical synthesis of randomized trials suggests that the reduction in cardiovascular risk from CTDN can be explained primarily on the basis of its ability to lower blood pressure rather than its influence upon non-BP related, pleiotropic effects.
Nuisance Signal in Resting-State fMRI Study

We systematically presented various nuisance signals in resting-state fMRI (R-fMRI) dataset. First, we examined the impact of different extraction methods on the default-mode pattern seeded by posterior cingulate cortex (PCC). Second, we compared their differences in test-retest reliability. Finally, we speculated the equivalence of removing global mean signal to removing gray matter mean signal.
Musculoskeletal molecular imaging: a comprehensive overview

Molecular imaging permits non-invasive visualization and measurement of molecular and cell biology in living subjects, thereby complementing conventional anatomical imaging. Herein, we review the emerging application of molecular imaging for the study of musculoskeletal biology. Utilizing mainly bioluminescence and fluorescence techniques, molecular imaging has enabled in-vivo studies of (i) the activity of osteoblasts, osteoclasts, and hormones, (ii) the mechanisms of pathological cartilage and bone destruction, (iii) skeletal gene and cell therapy with and without biomaterial support, and (iv) the cellular processes in osteolysis and osteomyelitis. In these applications, musculoskeletal molecular imaging demonstrated feasibility for research in a myriad of musculoskeletal conditions ranging from bone fracture and arthritis to skeletal cancer. Importantly, these advances herald great potential for innovative clinical imaging in orthopedics, rheumatology, and oncology.
Landscape, Process and Power: Re-evaluating Traditional Environmental Knowledge

Review of Landscape, Process and Power: Re-evaluating Traditional Environmental Knowledge . Serena Heckler, ed. 2009. Berghahn Books, New York. Pp. 304, 21 illustrations, bibliography, index. $95.00 (hardback). ISBN 978-1-84545-549-1
Structure of a C26H28 alkene formed via titanium-promoted reductive dimerization of 4-(spirocyclopropyl)-pentacyclo[5.4.0.02,6.03,10.05,9]undecan-8-one

A spiro-fused C26H28 “cage≓ dimer hydrocarbon contains two three-membered rings, two four-membered rings, eight five-membered rings, and two six-membered rings. The molecule is calculated by molecular mechanics to have 902 kJ/mol of strain energy distributed primarily between angle strain (457 kJ/mol) and torsional interactions (368 kJ/mol). Molecular mechanics calculations and a geometry-optimized ab initio calculation are used to analyze the bond lengths and bond angles in the molecule. There is one major discrepancy between observed and calculated distances.