cssi/SciSciGPT-SciSciNet huggingface dataset:
Site-directed mutagenesis of a reactive lysyl residue (Lys-247) of Rubisco activase.

Chemical modification of tobacco leaf ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase with water-soluble N-hydroxysuccinimide esters identified Lys-247 as a particularly reactive residue necessary for maximal catalytic activity [M.E. Salvucci (1993) Plant Physiol. 103, 501-508]. To further explore the role of Lys-247 in catalysis, this species-invariant residue of Rubisco activase was changed to Arg, Cys, and Gln by mutagenesis of a cDNA clone of the mature form of the tobacco enzyme. Analysis of the purified recombinant proteins showed that all three point mutations reduced the rate of ATP hydrolysis to 2 to 3% of the wild-type enzyme and completely abolished the ability of Rubisco activase to promote activation of decarbamylated Rubisco. Replacement of Lys-247 with Arg, Cys, or Gln had a comparatively minor effect on ATP binding, but eliminated the increase in ATPase-specific activity that normally occurs with increasing concentrations of Rubisco activase protein. In mixing experiments, the K247R mutant enzyme inhibited Rubisco activation by wild-type Rubisco activase, indicating that interactions between Rubisco and Rubisco activase were disrupted by even the most conservative of the substitutions. Chemical elaboration of the K247C mutant by treatment with 2-bromoethylamine converted 39% of the thiols at position 247 to the aminoethyl derivative, but failed to improve the catalytic performance of the mutant enzyme. Our results indicate that the requirement for a lysyl residue at position 247 of Rubisco activase is very stringent, consistent with its proposed role in coordinating precise interactions with gamma-phosphate of ATP.
Pushing the limit of metal-oxide nanowire chemical sensing: selective detection of NO 2 down to ppb levels

ABSTRACT We demonstrate detection of NO 2 down to ppb levels using transistors based on both single and multiple In 2 O 3 nanowires operating at room temperature. This represents orders-of-magnitude improvement over previously reported metal oxide film or nanowire/nanobelt sensors. A comparison between the single and multiple nanowire sensors reveals that the latter have numerous advantages in terms of great reliability, high sensitivity and simplicity in fabrication. Furthermore, selective detection of NO 2 can be readily achieved with multiple-nanowire sensors even with other common chemicals such as NH 3 , O 2 , CO and H 2 around. Keywords: In 2 O 3 nanowires, chemical sensor, selective detection 1. INTRODUCTION Chemical sensing based on various nanostructures 1-11 has attracted enormous attention, as this is widely perceived as one of the most promising areas for nanotechnology to generate significant impact. Among the chemicals studied, NO 2 is one of the most dangerous air pollutants, which plays a major role in the formation of ozone and acid rain; Continued or frequent exposure to NO
Measured attenuation of coplanar waveguide on CMOS grade silicon substrates with polyimide interface layer

The measured propagation constant of a coplanar waveguide on CMOS grade silicon with a polyimide interface layer is presented. It is shown that the transmission line can have an attenuation comparable to other transmission lines on Si substrates if the proper polyimide thickness is used.
Dynamic Control of Defects in a Two-dimensional Optically Assisted Assembly

In this paper we demonstrate controlled loading of a closely packed array of optical traps. We also describe the technical advantages of our method of filling the trap array (which makes use of an independent, steerable trap created by a separate objective lens), as well of our specific implementation of array generation by multi-beam interference. Microscopic polystyrene spheres are trapped and subsequently assembled into sites on a two-dimensional optical lattice, which is formed from the interference of two pairs of coherent laser beams via an optical setup that allows for simple, continuous variation of lattice parameters over a very wide range. Individual particles in the initial assembly are dynamically manipulated with the independent laser beam, which offers the freedom to generate either defect-free lattices or a lattice with designer defects. As examples we demonstrate the assembly of a defect-free square lattice and a lattice with a single vacancy.
Unusual endovaginal ultrasonography and magnetic resonance imaging of placental site trophoblastic tumor.

Abstract Previous reports of ultrasonographic and magnetic resonance imaging of placental site trophoblastic tumor have described a cystic appearance of this rare disease. We present the first case in which endovaginal ultrasonography and magnetic resonance imaging revealed a solid intramural mass. (A M J O BSTET G YNECOL 1993;170:750-2.)
Prenatal exposure to diethylstilbestrol in mice: Toxicological studies

The effect of prenatal exposure to diethylstilbestrol (DES) on the postnatal development of male and female genital tract function was studied. The placental transfer or radiolabeled (3H or 14C) DES was studied in pregnant mice. DES-associated radioactivity in the fetal plasma approximated that in maternal plasma 1/2 hr after intravenous administration of [3H]DES; 3H activity corresponding to DES in the fetal genital tract was about threefold higher. The decrease in reproductive capacity of female offspring from mice treated with DES during gestation was dose-related; a low incidence (10% or less) of cancer of the vagina, cervix, and/or uterus was also observed in these mice. Male offspring exposed prenatally to the highest dose (100 microng/kg) of DES in this study also had lower reproductive capacities. Lesions in the genital tract of these mice included epididymal cysts, inflammation, cryptorchidism, and nodular masses in the seminal vesicles and/or prostate gland. Such lesions and sterility were not observed at the lower DES doses. Histological studies with neonatal mice raise the possibility that Mullerian duct tissue may represent a site for the transplacental toxicity of DES in both the male and female fetus.
Single Molecule Observations of Fatty Acid Adsorption at the Silica/Water Interface: Activation Energy of Attachment†

Total internal reflection fluorescence microscopy was used to obtain real-time images of individual fluorescently labeled hexadecanoic acid molecules as they absorbed at the aqueous−fused silica interface. In contrast with laterally averaged ensemble measurements of surface coverage versus time, single-molecule observations provide direct, model-independent measurements of adsorption kinetics. Additionally, since the observations were made under steady-state conditions at extremely low coverage, effects due to transport kinetics did not influence the results, permitting accurate measurement of the fundamental attachment rate as a function of temperature, that is, the rate at which molecules are transferred to the surface from the subsurface layer. We found that the attachment rate systematically increased with increasing temperature; an Arrhenius analysis gave an activation energy of Ea = 19 ± 2 kJ/mol. We hypothesize that this energy, which is similar in magnitude to the strength of an OH···O hydrogen bo...
AppWatcher: unveiling the underground market of trading mobile app reviews

Driven by huge monetary reward, some mobile application (app) developers turn to the underground market to buy positive reviews instead of doing legal advertisements. These promotion reviews are either directly posted in app stores like iTunes and Google Play, or published on some popular websites that have many app users. Until now, a clear understanding of this app promotion underground market is still lacking. In this work, we focus on unveiling this underground market and statistically analyzing the promotion incentives, characteristics of promoted apps and suspicious reviewers. To collect promoted apps, we built an automatic data collection system, AppWatcher, which monitored 52 paid review service providers for four months and crawled all the app metadata from their corresponding app stores. Finally, AppWatcher exposes 645 apps promoted in app stores and 29, 680 apps promoted in some popular websites. The current underground market is then reported from various perspectives (e.g., service price, app volume). We identified some interesting features of both promoted apps and suspicious reviewers, which are significantly different from those of randomly chosen apps. Finally, we built a simple tracer to narrow down the suspect list of promoted apps in the underground market.
Ultrasound measurement of the fetal head: computer versus operator.

In obstetrical ultrasound practice, biparietal diameter, occipito-frontal diameter and head circumference are among the most commonly used fetal measurements. To minimize the limitations associated with manual measurement, we have undertaken an investigation with a focus on (1) the design of a personal computer-based system for automated measurements of biparietal diameter, occipito-frontal diameter and head circumference, and (2) integration of such a system (including measurements of abdomen and femur) into the routine obstetrical ultrasound examination. This report presents preliminary results of a comparison of computer-determined fetal head measurements with those obtained by an operator. Data were obtained from 75 consecutive singleton fetal ultrasound examinations free of any obvious structural anomalies. The computer obtained acceptable measurements of biparietal diameter, occipito-frontal diameter and head circumference from 74 images and failed on one image. There was a highly significant correlation between computer-determined measurements of biparietal diameter (r = 0.986), occipito-frontal diameter (r = 0.958) and head circumference (r = 0.972) and those obtained by the operators. The mean measurement difference (computer minus operator) was 1.87 ± 1.94 mm for biparietal diameter, 2.82 ± 4.13 mm for occipito-frontal diameter and −0.36 ± 9.87 mm for head circumference. These differences were independent of the operator's identity, the instrument used and gestational age. The key finding of this study is that, with the use of inexpensive personal computer technology, it is possible to design and implement a system that can give fetal head measurements which correlate highly with manual determination by a skilled operator and which take a fraction of the time. Copyright © 1991 International Society of Ultrasound in Obstetrics and Gynecology
Triggering TLR signaling in vaccination

Toll-like receptors (TLRs) are a family of pattern-recognition receptors that are an important link between innate and adaptive immunity. Many established, as well as experimental, vaccines incorporate ligands for TLRs, not only to protect against infectious diseases but also in therapeutic immunization against noninfectious diseases, such as cancer. We review the underlying mechanisms by which engagement of TLR signaling pathways might trigger an adaptive immune response after immunization. Although the engagement of TLR signaling pathways is a promising mechanism for boosting vaccine responses, questions of efficacy, feasibility and safety remain the subject of active investigation.
Cryptic Blooms: Are Thin Layers the Missing Connection?

Harmful algal blooms (HABs) are common in Monterey Bay, CA, and have resulted in repeated closures of shellfish fisheries and the poisoning and death of marine mammals. In the majority of instances, HAB events in this region are first detected by the presence of sick or dying animals. The phrase “cryptic blooms” was adopted to denote the appearance of poisoning at higher trophic levels with no prior evidence of a large phytoplankton bloom. We hypothesize that the onset of many HAB events goes undetected because the bloom is initially concentrated in discrete thin subsurface layers in the water column that are easily missed by conventional sampling and monitoring methods. In this paper, we report on the detection and monitoring of a subsurface layer of phytoplankton in northern Monterey Bay, CA, using a high-resolution, autonomous profiler. This ‘thin layer,’ which measured from 10 cm to 3 m in thickness (85% < 2 m; 54% < 1 m), persisted over a 7-day period near the base of the pycnocline. The phytoplankton assemblage in the layer was primarily composed of a multi-species assemblage of Pseudo-nitzschia including the toxin-producing species Pseudo-nitzschia australis. Concentrations of toxic phytoplankton (P. australis), cyanobacteria, and bacteria in the layer were significantly higher than outside the layer (P < 0.05). Counts of total Pseudo-nitzschia spp. showed similar levels of enrichment in the layer compared to outside the layer. Our findings indicate that, when monitoring for HABs, it is critical to sample at scales appropriate to resolve thin layers. Thin layers have been identified as a common recurrent feature in a variety of coastal systems, suggesting that the use of autonomous high-resolution vertical profilers coupled with targeted sampling, could allow more timely detection of HABs in many coastal environments.
Synaptic Neurochemical Alterations Associated with Neuronal Degeneration in an Inherited Cerebellar Ataxia of Gordon Setters

Canine Inherited Ataxia (CIA) is an autosomal recessive cerebellar disease of Gordon Setters associated with degeneration of Purkinje and granule cells. To define specific biochemical correlates of neuronal loss, synaptic neurochemical parameters were measured in three cerebellar regions (vermis, "pars intermedia," and hemisphere) at early and late stages of this disease. At one and a half years of age, affected dogs showed the most severe lesions in the "pars intermedia," with a 39% decrease in the number of Purkinje cells and a 29% decrease in granule cells. Neurochemical measurements demonstrated decreased [3H]muscimol binding and elevations in norepinephrine concentration (248% above control) and [3H]glutamate receptor binding (118% above control). At five years of age, reduction of Purkinje cells in the three cerebellar regions ranged from 65 to 91% while loss of granule cells was between 13 and 53%. [3H]Muscimol binding remained low throughout the cerebellum (38 to 59% of control) and norepinephrine concentration and [3H]glutamate binding were markedly reduced from the levels observed at one and a half years. Glutamate decarboxylase activity, [3H]QNB binding and GABA concentration were relatively unaffected. Our results indicate that neurochemical parameters associated with cerebellar neuronal systems demonstrate specific alterations in a chronic degenerative disorder. This study also indicates the importance of evaluating neurochemical measurements with regard to both spared and degenerating neuronal systems and emphasizes the role of compensatory neurochemical alterations in cerebellar degenerative disorders.
Nerve growth factor rapidly stimulates tyrosine phosphorylation of phospholipase C-γ1 by a kinase activity associated with the product of the trk protooncogene

Abstract Nerve growth factor (NGF) promotes the survival and differentiation of specific populations of neurons. The molecular mechanisms by which cells respond to NGF are poorly understood, but two clues have emerged recently. First, NGF rapidly stimulates tyrosine phosphorylation of several unidentified proteins in the NGF-responsive pheochromocytoma cell line PC12 [Maher, P. (1988) Proc. Natl. Acad. Sci. USA 85, 6788-6791]. Second, the protein-tyrosine kinase encoded by the protooncogene trk (p140trk), a member of the receptor class of tyrosine kinases, becomes activated and phosphorylated on tyrosine after NGF treatment of PC12 cells [Kaplan, D. R., Martin-Zanca, D. & Parada, L. F. (1991) Nature (London) 350, 158-160]. We now report that NGF rapidly induces tyrosine phosphorylation of phospholipase C-gamma 1 (PLC-gamma 1), and we present evidence that the responsible tyrosine kinase is either p140trk or a closely associated protein. Treatment of responsive cells with NGF elicited phosphorylation of PLC-gamma 1 on tyrosine and serine. PLC-gamma 1 immunoprecipitated from NGF-stimulated cells was phosphorylated in vitro by coprecipitating protein kinase activity, and the phosphorylations occurred principally on tyrosine. The responsible kinase could be depleted from cellular lysates by antibodies specific for p140trk. This procedure also depleted a 140-kDa protein that normally coprecipitated with PLC-gamma 1 and became phosphorylated on tyrosine in vivo in response to NGF. Analysis of tryptic peptides from PLC-gamma 1 indicated that the residues phosphorylated in vitro by p140trk-associated kinase activity were largely congruent with those phosphorylated in vivo after NGF treatment. Our findings identify PLC-gamma 1 as a likely substrate for the trk-encoded tyrosine kinase, and they provide a link between NGF-dependent activation of p140trk and the stimulation of intracellular second messenger pathways.
Burkitt's lymphoma

Cancer is the second leading cause of death in children and, among cancers, lymphoma is the third most frequently diagnosed type. The majority of these are non-Hodgkin's lymphomas (NHL). Although NHL have been grouped in a variety of confusing ways, recent research in cytogenetics and immunology, coupled with a better understanding of the normal pathways of lymphoid differentiation, has greatly lessened this confusion. Burkitt's lymphoma (BL) is a type of B-cell NHL which is sub-classified as either endemic (African) or non-endemic (American). Kinetic studies have demonstrated a doubling time of only 24 h. As a result of this extremely rapid growth, symptomatic complaints occur early in the disease course. Structures contiguous to the primary become compressed and metabolic derangements occur. Signs of chronic debilitation such as cachexia, diarrhea, generalized lymphadenopathy, and weight loss usually are not found. Thirteen cases of American BL have been treated since 1980 at the Texas Children's Hospital and form the basis of this review. Ten patients had obstructive abdominal symptoms including constipation and pain, and 3 had masses in the neck, maxilla, or tonsil. Systemic manifestations included ascites, jaundice, fever, and hepatosplenomegaly. Two patients ultimately developed central facial nerve paralysis.
The Euro-Atlantic Security Dilemma: France, Britain, and the ESDP

(2005). The Euro-Atlantic Security Dilemma: France, Britain, and the ESDP. Journal of Transatlantic Studies: Vol. 3, No. 1, pp. 39-54.
Multi-electrode stimulation and recording in the isolated retina.

Abstract As part of an exploration of the feasibility of an epi-retinal prosthesis, we developed an experimental method to electrically stimulate and record from retinal neurons using a micro-fabricated multi-electrode array. An isolated retina is placed on an array of 10 μm diameter disk electrodes with the ganglion cell side of the retina facing the electrode surfaces. The retina is bathed in oxygenated Ames’ medium and warmed in order to sustain it in vitro for the duration of an experiment, typically 4–9 h. To reduce stimulus artifacts, the electrodes are grouped into two clusters — one used for stimulation and the other for recording — spaced several hundred microns apart, and electrodes are insulated with both silicon nitride and a 10 μm thick layer of polyimide. Stimuli are delivered to the array using an optically isolated current source stimulator, and the resulting responses recorded with an eight channel nerve response amplifier. Stimulation and recording are performed under computer control. A variety of physiologic measurements is described in order to illustrate the strengths and drawbacks of this method.
"They could make their victims dull": genders and genres, fantasies and cures in Colonial Southern Uganda.

THIS ARTICLE IS ABOUT MEDICAL HISTORY and historical methodology. It describes the encounter between Western biomedicine and the local peoples of southern Uganda.' It argues that oral accounts of African rumors that white people captured Africans and took their blood can be read alongside medical missionary writings about triumphant drugs and vanquished superstitions to illuminate the context in which Western biomedicine was practiced. This essay is not about the clash of beliefs or of technologies; it is about what technologies were believed to be and about how much power was invested in their application. It is about cures that were rubbed on the skin or inhaled; it is about needles and scalpels that penetrated the skin and invaded the body. The two sets of sources I use overlap only to a degree. The missionaries recorded their arguments with and treatments of Africans in monthly fund-raising magazines published from 1899 to about 1935. The Church Missionary Society's Mercy and Truth (after 1922, The Mission Hospital) was published in England; it contained authored vignettes that were not always less fantastic than the oral source material. Nevertheless, they provide a chronological record of colonial medicine unlike any other: missionary medicine was the most prevalent form of rural health care in Uganda until the 1950s, and it represented itself in stark contrast to African medicine for at least as long. Moreover, in Uganda, missionary
School Security: For Whom and With What Results?

This study utilized school-level data from several combined national databases to address two questions regarding school security policy: (1) What are the school characteristics related to levels of security? (2) How does security relate to school suspension, dropout, and college attendance rates? Among the predictors of school security, having a high proportion of African American students was the strongest. This race/ethnicity effect remained significant when statistically controlling for socioeconomic status (SES), neighborhood crime, school indiscipline, urbanicity, and geographic region. Security was positively associated with school suspension rates but had no relationship to dropout or college attendance rates. Administrator roles and alternatives are discussed.
Pattern Matching in Constrained Sequences

Constrained sequences find applications in communication, magnetic recording, and biology. In this paper, we restrict our attention to the so-called (d, k) constrained binary sequences in which any run of zeros must be of length at least d and at most k, where 0lesd<k. In some applications one needs to know the number of occurrences of a given pattern w in such sequences, for which we coin the term constrained pattern matching. For a given word w or a set of words W, we estimate the (conditional) probability of the number of occurrences of w in a (d, k) sequence generated by a memoryless source. As a by-product, we enumerate asymptotically the number of (d, k) sequences with exactly r occurrences of a given word w, and compute Shannon entropy of (d, k) sequences with a given number of occurrences of w. Throughout this paper we use techniques of analytic information theory such as combinatorial calculus, generating functions, and complex asymptotics.
Fluorescent Probes of the Molecular Environment within Mesostructured Silica/Surfactant Composites under High Pressure

The molecular environment of the organic component of periodic silica/surfactant composites under elevated pressure is studied using a rigidochromic Re complex as a molecular probe. This amphiphilic organometallic complex is incorporated into the organic component of the silica/surfactant composite during synthesis. Shifts in the luminescence peak position of the Re complex indicate changes in the rigidity or viscosity of the surrounding matrix. In the experiment, under elevated pressure, the luminescence from the complex provides a measure of the changing molecular environment inside the mesophase. The results confirm conclusions from earlier experiments on the mechanical properties of silica/surfactant composites under high pressure: Although an increase in viscosity is observed with increasing pressure, the molecular environment does not become fully rigid until pressures as high as 10 GPa have been reached. This pressure is significantly higher than the solidification point of most pure organic phases and suggests that the mechanical strength of the silica framework provides a protected molecular environment for organic molecules situated within the silica nanopores.
The sulfur vapor pressure over pyrite on the surface of Venus

Abstract The total pressure and molecular speciation of sulfur vapor (dominantly S2) over pyrite at Venus surface temperatures (≈ 390–470°C) are important for modeling atmospheric chemistry and geochemistry of sulfur gases and minerals on Venus. The sulfur vapor pressure over pyrite in CO2 and CO2 gas mixtures, which are relevant to Venus, has not been previously measured. Instead, previous measurements were generally done in closed systems, such as sealed, evacuated silica tubes. We measured the sulfur vapor pressure over pyrite in an open system where carrier gas is flowing through a gas mixing furnace, from 441 to 591°C in He, N2, CO2, and CO2SO2CO mixtures using a standard technique, the transpiration method (Merton, U. and Bell, W. E. (1967) The transpiration method. In The Characterization of High Temperature Vapors, ed. J. W. Margrave, pp. 91–114. Wiley, New York). The data show that the sulfur vapor pressure over pyrite is the same in inert gas and in CO2-bearing gases. Our data also agree with literature vapor pressure data. Thermodynamic calculations show that the laboratory vapor pressure data are also valid at Venus surface pressures (≈ 50–100 bar). Finally, we present recommended values for the sulfur vapor pressure and calculate the molecular speciation of sulfur vapor over pyrite at Venus surface temperatures.
Characterization of a CD4-positive T-cell line derived from an athymic (nu/nu) mouse.

Abstract We have isolated a Thy-1 + , CD3 + , CD4 + T-cell line from the spleen of a l2-week-old nu/nu (nude) BALB/c mouse. The cell line is clonal, and it expresses an αβ T-cell antigen receptor. Upon activation, these cells secrete IL-2 but not IL-4, putting them in the T h 1 category. The cells can be triggered to proliferate and secrete lymphokines in the presence of irradiated syngeneic or allogeneic splenic feeder cells that express a variety of MHC haplotypes. This response is MHC class II-specific, because it can be blocked by either anti-Ia or anti-CD4 antibodies. From the response pattern of this T-cell line, we conclude that it recognizes a common determinant on class II MHC antigens. This nude mouse T-lymphocyte presumably has not undergone thymic selection. Therefore its unique specificity may reflect both the bias of T-cell antigen receptor genes for encoding receptors that recognize MHC molecules and the requirement for functional thymic epithelial cells for the efficient education of a self-MHC-restricted repertoire.
Differential expression of LHRH-receptor in bovine nasal tissue and its role in deslorelin delivery.

Abstract Deslorelin, a luteinizing hormone releasing hormone (LHRH) agonist, is transported via the LHRH-receptor (LHRH-R) and exhibits regional variation as follows: inferior turbinate posterior (ITP) > medium turbinate posterior (MTP) > medium turbinate anterior (MTA) of the bovine nasal mucosa. Differential LHRH-R expression in various regions of the nose is a potential explanation for regional variation in deslorelin transport. Thus, the objective was to determine whether LHRH-R expression exhibits regional variation in bovine nasal mucosa. LHRH-R density ( B max ) and affinity constant ( K d ) were determined by saturation experiments using 0.5 mg tissue in the presence of increasing amounts of I 125 -deslorelin (100–100,000 cpm) at 4 °C for 4 h. The 50% inhibitory concentration (IC 50 ) was determined by competition experiments using various amounts of unlabelled deslorelin (0.01–3000 ng) at 4 °C for 4 h. LHRH-R mRNA and protein expressions were determined using real-time PCR and Western blot analysis, respectively. LHRH-R B max and K d varied between the regions of excised bovine nasal mucosa: ITP > MTP > MTA. The inhibition experiments yielded two IC 50 concentrations which exhibited trends similar to B max and K d . Real-time PCR and Western blot analysis indicated that LHRH-R expression exhibits similar trends: ITP > MTP > MTA. We identified two deslorelin binding sites in the nasal tissues, with high affinity sites representing approximately 60–70% of the total sites available. In summary, regional differences in nasal deslorelin transport correlate with regional differences in LHRH-R expression, with LHRH-R expression, peptide binding, and transport being the highest in the inferior turbinate posterior region of the nose.
Perfusion Versus Function: The Ischemic Cascade in Demand Ischemia Implications of Single-Vessel Versus Multivessel Stenosis

Background— We hypothesized that during demand ischemia, abnormal perfusion will precede abnormal function, the spatial extent of perfusion abnormality will be greater than that of functional abnormality, and the spatiotemporal disparity between abnormal perfusion and abnormal function will be more marked in the presence of single-vessel stenosis (SVS) versus multivessel stenosis (MVS). Methods and Results— Nine dogs each underwent either SVS or MVS placement. These noncritical stenoses were classified as mild, moderate, or severe on the basis of the transstenotic pressure gradient (10 to 14, 15 to 20, or >20 mm Hg). Dobutamine was infused starting at 10 and reaching 40 μg/kg−1 · min−1. Wall thickening (WT) and myocardial perfusion (myocardial contrast echocardiography) were assessed at each stage. Resting perfusion and function were normal in all dogs. In SVS, abnormal perfusion (delayed rate of microbubble replenishment) was seen at the lowest dose of dobutamine irrespective of the stenosis severity, wh...
Spherical gravitating systems

Abstract Due to both the infinite range and singularity of the Newtonian gravitational potential, the thermodynamics of systems with predominantly gravitational forces differs greatly from “chemical” systems dominated by short-range inter-atomic forces. Consider a typical star: As it ages it radiates energy, contracts, and gets hotter. Therefore, its heat capacity is negative, a situation which cannot exist in a chemical system. Here we will consider an idealized class of model gravitational systems consisting of concentric, thin, mass shells. Using both mean field theory and dynamical simulation, we will show that when the singularity is shielded, as it must be in nature, even if the shells are non-rotating, the system can undergo a phase-transition to a more centrally condensed state. We will describe the main features of the transition, show how it contradicts our usual intuition, and discuss possible astrophysical applications. We then discuss the case where the shells are allowed to rotate. We will show that if all the shells have the same squared angular momentum, then the rotational barrier can induce a phase-transition without the need for additional shielding. Finally we use the fact that for a spherical system in the mean field limit there is an additional integral of the motion besides the energy, namely the sum of the squares of the angular momentum, to introduce and study two new ensembles. We show that gravothermal catastrophe is still possible in generalizations of both the canonical ensemble (CE) and microcanonical ensemble (MCE) which include the additional integral and, therefore, in the absence of additional shielding, a phase-transition will be excluded.
Analysis and Application of a Nonlinear Vibration Absorber

The authors investigate theoretically and experimentally the performance of a recently developed quadratic vibration absorber that is based on the saturation phenomenon. They consider the problem o...
Whole genome microarray analysis of gene expression in an imprinting center deletion mouse model of Prader-Willi syndrome.

Prader–Willi syndrome (PWS) is caused by loss of paternally expressed genes in the 15q11-q13 region. To further characterize alterations in gene expression in this classical obesity syndrome we used whole genome microarrays to study a PWS mouse model resulting from a paternally derived imprinting center (IC) deletion (PWS IC deletion). These mice die generally within 2–3 days of life (reflective of failure to thrive in infants with PWS) and therefore, the analysis was performed on RNA extracted from the whole brain of PWS IC deletion mice and normal littermates at less than 24 hr after birth. Of more than 45,000 probes examined, 26,471 (59%) were detected for further analysis, and 69 had a significant change in expression of at least 1.5-fold and a false discovery rate (FDR) of 5%. Eight of the genes with differential expression were imprinted and from the PWS critical region (PWSCR). The three genes with the highest expression in the PWS IC mice were pro-opiomelanocortin (Pomc) and two transcripts of unknown function. Pomc knockout mice have been shown to develop obesity. Therefore, elevated Pomc RNA in PWS IC deletion neonatal mice may be an important genetic factor in the survival of these mice as it may affect eating behavior. Interestingly, Mc5r, a melanocortin receptor known to directly respond to Pomc expression changes, was upregulated as well. Mc5r is known to be involved with thermoregulation which is reportedly abnormal in PWS infants. These observations support a role for Pomc and the network of genes involved in regulating energy homeostasis in the early clinical findings of failure to thrive observed in PWS. Other notable patterns include three previously unstudied transcripts that are expressed only from the paternal allele under regulatory control of the IC and include AK013560, BB3144814, and BB182944 (whose genes are located in the mouse PWSCR on chromosome 7B). As expected, all the known paternally expressed genes from the PWSCR had detection signals below the threshold in the PWS IC deletion mice but were clearly detectable in control littermates. Several of the genes in this study were further examined by quantitative reverse transcription-PCR (RT-PCR) to confirm their expression status. Further analysis of gene expression in these mice may lead to novel pathways affected in PWS. These results, along with other recent reports, suggest that the cumulative effect of modest changes in expression of many genes, especially genes involved in energy metabolism, contribute to the failure to thrive of infants with PWS. 2006 Wiley-Liss, Inc.
Porcine small intestinal submucosa as a percutaneous mid-urethral sling: 2-year results.

OBJECTIVE To report the 2-year follow-up results on patients treated with a novel minimally invasive outpatient procedure for placing a mid-urethral sling, using porcine small intestinal submucosa (SIS). PATIENTS AND METHODS Thirty-four women with urodynamic evidence of stress urinary incontinence (SUI, 19) or of SUI with a positive cough test (15) were treated. A curved ligature carrier was used to create a tract between bilateral suprapubic stab incisions and a 2-cm mid-urethral vaginal incision. A suture secured to each end of the SIS sling was placed through the eyelet of the ligature carrier. Extraction was used to position the sling at the mid-urethra, providing a backboard of support that was remodelled with ingrowth of the patient's autologous tissue. RESULTS SUI was reportedly cured in 27 of the 34 women (79%) at the 2-year follow-up; three (9%) of those with no complete resolution were pleased with their results, because the improvement allowed them to wear an average one or fewer pads per day. One patient developed de novo urge incontinence. Three patients (9%) developed suprapubic inflammation at 10, 21 and 45 days after surgery; all resolved, but one had a recurrence of SUI. No prolonged retention, erosion or other complications were noted. CONCLUSIONS Early results with the percutaneous mid-urethral placement of SIS are promising and potentially comparable with those after using synthetic minimally invasive slings.
Secure control systems with application to cyber-physical systems

Control systems are computer-based systems with networked units consisting of sensors, actuators, control processing units, and communication devices. The role of control system is to interact, monitor, and control physical processes. Reactive power control is a fundamental issue in ensuring the security of the power network. It is claimed that Synchronous Condensers (SC) have been used at both distribution and transmission voltage levels to improve stability and to maintain voltages within desired limits under changing load conditions and contingency situations. Performance of PI controller corresponding to various tripping faults are analyzed for SC systems. Most of the effort in protecting these systems has been in protection against random failures or reliability. However, besides failures these systems are subject to various signal attacks for which new analysis are discussed here. When a breach does occur, it is necessary to react in a time commensurate with the physical dynamics of the system as it responds to the attack. Failure to act swiftly enough may result in undesirable, and possibly irreversible, physical effects. Therefore, it is meaningful to evaluate the security of a cyber-physical system, especially to protect it from cyber-attack. Illustrative numerical examples are provided together with an application to the SC systems.
Neutron Diffraction Study of Orthorhombic BaTi O 3

The atomic positions of ferroelectric BaTi${\mathrm{O}}_{3}$ in its orthorhombic phase have been determined by a singlecrystal neutron diffraction analysis. Pillar-shaped crystals with their major axes along the cubic [110] direction were maintained as single domains by the application of an electric field. The structure deduced can be viewed as a framework of slightly distorted oxygen octahedra, in which the central Ti ions are displaced towards one of the octahedron edges (polar axis) by 0.13 A. The Ba ions are also shifted in the same direction but by the smaller amount of 0.07 A. A comparison of this structure with that of the tetragonal phase suggests the essential role of Ti in the ferroelectricity of this crystal as treated by Slater.
DNA damage as an intermediate biomarker in intervention studies

The development of sensitive assays for measurement of DNA damage in humans has great potential for enhancing intervention studies. Methods for DNA adduct measurement include immunoassays, [32p] postlabeling, high-performance liquid chromatography with fluorescence or electrochemical detection, and gas chromatography/mass spectroscopy. It is now well established that DNA adducts are a marker of exposure to various environmental, lifestyle, or occupational chemical carcinogens. Our own studies concentrate on immunologic detection of adducts by enzyme-linked immunosorbent assay (ELISA) of isolated DNA or quantitative immunohistochemical analysis of intact cells. Polycyclic aromatic hydrocarbon (PAH)-DNA adducts are elevated in blood cells of foundry and coke oven workers, individuals with high levels of exposure to environmental air pollution, and smokers. The study in smokers also found an inverse relationship between serum antioxidants and PAH-DNA, and is the basis for an ongoing antioxidant intervention. DNA adducts of PAH and 4-aminobiphenyl and oxidative DNA damage (8-oxo-deoxyguanosine) are being measured in blood mononuclear cells and exfoliated oral and bladder cells from subjects on antioxidants or placebo. Data on published intervention studies investigating oxidative damage and general aromatic DNA adducts measured by postlabeling are also summarized. These studies have already demonstrated that DNA adducts can be modulated by interventions and suggest that they can provide important mechanistic information in support of larger scale studies.
Modeling semiconductor lasers : simulation of devices based on microscopic physics

We are currently developing 2 semiconductor laser simulators built on a first-principles microscopic physics basis. The first is a PC-based, plane-wave simulator for both component and system-level design of low-power optoelectronic devices. The second is a supercomputer-based simulator that models the fully time-dependent and spatially-resolved optical, carrier, and temperature fields for arbitrary geometry, high-power semiconductor lasers. Both simulators are based on a comprehensive gain model that includes the relevant bandstructure of the quantum wells and confining barrier regions together with a fully quantum mechanical many-body calculation that takes all occupied bands into account.
Catecholamine release by intracerebral perfusion of 6-hydroxydopamine and desipramine.

The rate of catecholamine release was examined at perfusion sites in the diencephalon of the unanesthetized rat during the perfusion of a solution of 6-hydroxydopamine (6-OHDA) or desipramine (DMI). Endogenous stores of norepinephrine (NE) and dopamine (DA) were first tagged by the cerebral microinjection of 14C- or 3H-labelled NE or DA. After successive control perfusates were collected with a push—pull cannula system, 6-OHDA, in a concentration of 5.0, 0.5 or 0.1 mg/ml, was perfused at 20–23 μl/min through a site in the rat's brain. The compound induced a dose-related release of both NE and DA. In control experiments, 6-OHDA exerted a non-specific releasing effect on 3H-inulin which was not dose dependent. In addition, DMI, an NE reuptake inhibitor in a concentration of 10.0, 2.0 or 0.5 mg/ml, was perfused through 23 sites in the brain following the injection of labelled NE. DMI enhanced the recovery of NE in the push—pull effluent at the 10.0 mg/ml concentration only. However, an augmented efflux of 3H-inulin was also observed during the perfusion of the highest concentration of DMI. These results support the view that 6-OHDA releases catecholamines from endogenous storage sites, but also indicate a strong non-specific releasing action of this compound possibly at extracellular or non-catecholaminergic loci.
Neuroimaging of Non-Human Primates

Welcome to this special issue of the Open Neuroimaging Journal which focuses on neuroimaging studies of non-human primates (NHPs) as presented by leaders in the field. NHPs are important animal models because of their genetic, ontogenic, and physiological similarities to humans. Research using NHPs has significantly advanced our understanding of neuroscience, neurodegerative disorders, aging and development. NHP models have played a vital role in vaccine, AIDS and infectious disease research, among others. Magnetic resonance imaging (MRI) has become a powerful research and clinical imaging tool because it can provide non-invasive anatomical, physiological and functional images at high spatial and temporal resolution with excellent soft tissue contrast. NHP studies benefit from the modern high-field MR scanners equipped with high performance gradients and multi-channel RF receivers and the innovative imaging and analysis tools. Because custom NHP scanners are not widely available, most NHP MRI studies are performed on human scanners. There are a few major changes for NHP studies and they include: i) cost and the availability of NHP resources, ii) expertise in handling NHPs and maintaining stable animal preparations, and iii) the need to achieve sufficient spatial resolution and signal-to-noise ratio for NHP brains which are much smaller than the human brains. Despite these challenges, there have been substantial progresses made and many of the knowledge gained have benefited human studies and vice versa. This special issue describes some novel approaches and applications in the neuroimaging studies of NHPs. Darceuil and colleagues and Wey and colleagues describe the use of multimodal MRI to study ischemic stroke in the clinically relevant rhesus and baboon models. Chen and colleagues demonstrate how very high spatial resolution fMRI can be applied to study the topography of somatosensory cortex. Rane and Duong demonstrate that diffusion tensor imaging with long diffusion time improves fiber tracking in rhesus brains. Kochunov and Phillips describe development of corpus callosum during in-utero and postnatal maturation in baboons. Fedorov and colleagues show how atlas-guided segmentation can be used to calculate robust gray- and white-matter tissue maps in the velvet monkey brains. Dubowitz and colleagues develop a frameless stereotaxic localization strategy for NHP brains. And last but not least, Szabo and colleagues describe the MRI study of seizure-disorders in baboons. I am grateful to all of the contributors to this special issue for their time and efforts.
NMDA Receptors on Non-Dopaminergic Neurons in the VTA Support Cocaine Sensitization

Background: The initiation of behavioral sensitization to cocaine and other psychomotor stimulants is thought to reflect Nmethyl-D-aspartate receptor (NMDAR)-mediated synaptic plasticity in the mesolimbic dopamine (DA) circuitry. The importance of drug induced NMDAR mediated adaptations in ventral tegmental area (VTA) DA neurons, and its association with drug seeking behaviors, has recently been evaluated in Cre-loxp mice lacking functional NMDARs in DA neurons expressing Cre recombinase under the control of the endogenous dopamine transporter gene (NR1 DATCre mice). Methodology and Principal Findings: Using an additional NR1 DATCre mouse transgenic model, we demonstrate that while the selective inactivation of NMDARs in DA neurons eliminates the induction of molecular changes leading to synaptic strengthening, behavioral measures such as cocaine induced locomotor sensitization and conditioned place preference remain intact in NR1 DATCre mice. Since VTA DA neurons projecting to the prefrontal cortex and amygdala express little or no detectable levels of the dopamine transporter, it has been speculated that NMDA receptors in DA neurons projecting to these brain areas may have been spared in NR1 DATCre mice. Here we demonstrate that the NMDA receptor gene is ablated in the majority of VTA DA neurons, including those exhibiting undetectable DAT expression levels in our NR1 DATCre transgenic model, and that application of an NMDAR antagonist within the VTA of NR1 DATCre animals still blocks sensitization to cocaine. Conclusions/Significance: These results eliminate the possibility of NMDAR mediated neuroplasticity in the different DA neuronal subpopulations in our NR1 DATCre mouse model and therefore suggest that NMDARs on non-DA neurons within the
Preventing Acute Leukemia Relapse after Allogeneic Transplants: How to Move Forward?

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