cssi/SciSciGPT-SciSciNet huggingface dataset:
Reliability studies of two flip-chip BGA packages using power cycling test

Abstract Power cycling tests of the second level reliability of two flip-chip BGA packages are discussed in this paper. The first one is for a flip-chip on laminate package (FCPBGA) and the other for a flip-chip on ceramic package (FCCBGA). For the FCPBGA, test strategies will be first discussed and then focus will be given to a unique failure mode associated with this type of packages assembled back to back onto printed circuit board. Instead of anticipated failures of the corner solder joints under the die shadow, as in the case of wire-bonded packages, we found that solder joints failed first in the central region of the package and then failures of solder joints spread out in the radial direction from the center of the package. Explanation will be given to the physical mechanisms that caused this type of failure. For the FCCBGA, the improved test strategies based on what has been learned from the test of FCPBGA will be presented and focus will be given to the effect of different parameters on the second level reliability of the package. Here, because of the increased rigidity of the ceramic substrate solder joints failed as expected first at the corner(s) of the ceramic substrate. Based on the test results and the modified Coffin–Manson equation, predictions or the solder joint fatigue life will be shown.
Probing the NADH- and Methyl Red-binding site of a FMN-dependent azoreductase (AzoA) from Enterococcus faecalis.

AzoA from Enterococcus faecalis is a member of the polymeric flavin-dependent NADH-preferred azoreductase group. Little is known about the binding and interaction of NADH and azo dye in the azoreductase group. A synergetic strategy based on computational prediction, reverse genetics validation coupled with site-directed mutagenesis, and reconstruction of mutation network was used to investigate the binding and interaction of NADH and a model azo dye, Methyl Red, with AzoA. Methyl Red and NADH interacted in a unique binding mode in which the benzoic acid moiety of Methyl Red and the nicotinamide ring of NADH were not parallel to the flavin isoalloxazine ring, but lay against it at angles of ∼45° and ∼35°, respectively. The adenine ribose moiety of NADH was surrounded by loop l2 on chain B and α3 on chain A in a typical Rossmann fold. There were 12 and 19 amino acid residues that could participate in the binding of Methyl Red and NADH, respectively, especially the residues Tyr-129 and Asp-184. The functional perturbation effects of 13 residues, including Tyr-129 and Asp-184, were mapped to reconstruct the mutation network, which confirmed the proposed binding modes and also provided insights into the interaction among NADH, FMN and Methyl Red.
The diagnostic value of the aspirin tolerance test

Abstract The aspirin tolerance test was systematically applied to 56 individuals evaluated in our coagulation laboratory and its diagnostic value assessed. The test was only utilized when the pre-aspirin bleeding time did not exceed 8 min, a time below which 95% of our normals fell. When plotted on probability paper both pre- and postaspirin bleeding times appeared to be log normally distributed with the only readily apparent difference being a shift in the mean. Nine of the tested group were diagnosed as having (or probably having) platelet-related bleeding disorders. However, none of these individuals showed a post-aspirin bleeding time that differentiated them from the rest of the population. The failure of the aspirin tolerance test to eliminate the need for other diagnostic procedures leads us to recommend that this procedure not be used as a preliminary diagnostic ‘screening’ test.
Overview of the SAGE III Experiment

ABSTRACT The Stratospheric Aerosol and gas Experiment III (SAGE III) is part ofthe NASA EOS program designedfor long term monitoring of atmospheric ozone and aerosol, together with other atmospheric speciesimportant to the study of global change. SAGE III is an advanced version ofthe previous occultationinstruments such as SAM II, SAGE I, and SAGE II which have provided long term data on aerosol andozone for the last twenty years. SAGE III will continue these long term measurements well into the firstdecade of the 2 1st century. SAGE III will measure profiles of aerosols, ozone, water vapor, nitrogendioxide, temperature, pressure, chlorine dioxide, and nitrogen trioxide using the solar and lunar occultationtechniques. Currently two SAGE III instruments will be launched between 1999 and 2003. The FirstSAGE III will be on a Russian Meteor 3M spacecraft to be launched in the Fall of 1999. The second SAGEIII will be on the Space Station in 2003.Keywords: remote sensing, space-borne instrument, aerosols, ozone, environmental monitoring, climatemonitoring.
SU-E-T-473: A Patient-Specific QC Paradigm Based On Trajectory Log Files and DICOM Plan Files

Purpose: To evaluate a remote QC tool for monitoring treatment machine parameters and treatment workflow. Methods: The Varian TrueBeamTM linear accelerator is a digital machine that records machine axis parameters and MLC leaf positions as a function of delivered monitor unit or control point. This information is saved to a binary trajectory log file for every treatment or imaging field in the patient treatment session. A MATLAB analysis routine was developed to parse the trajectory log files for a given patient, compare the expected versus actual machine and MLC positions as well as perform a cross-comparison with the DICOM-RT plan file exported from the treatment planning system. The parsing routine sorts the trajectory log files based on the time and date stamp and generates a sequential report file listing treatment parameters and provides a match relative to the DICOM-RT plan file. Results: The trajectory log parsing-routine was compared against a standard record and verify listing for patients undergoing initial IMRT dosimetry verification and weekly and final chart QC. The complete treatment course was independently verified for 10 patients of varying treatment site and a total of 1267 treatment fields were evaluated including pre-treatment imaging fields where applicable. In the context of IMRT plan verification, eight prostate SBRT plans with 4-arcs per plan were evaluated based on expected versus actual machine axis parameters. The average value for the maximum RMS MLC error was 0.067±0.001mm and 0.066±0.002mm for leaf bank A and B respectively. Conclusion: A real-time QC analysis program was tested using trajectory log files and DICOM-RT plan files. The parsing routine is efficient and able to evaluate all relevant machine axis parameters during a patient treatment course including MLC leaf positions and table positions at time of image acquisition and during treatment.
ANIMAL MODEL OF BENZOCAINE INDUCED METHEMOGLOBINEMIA

Methemoglobinemia has been reported in a small number of infants after topical application of benzocaine. Since it is a widely used medication, these rare occurrences have been considered to possibly represent idiosyncratic response. Varying amounts of benzocaine (1.5,3,6,12.5,25,50,100 mg) were administered by stomach tube, in a single 1.0 ml bolus, to 117 young (approx. 175 gm) Charles River CD male rats. Animals were sacrificed after 30 or 60 minutes and methemoglobin levels determined spectrophotometrically. Methemoglobin levels were negligible at the lowest dose of benzocaine (1.5 mg), but significant levels (20 - 70% of total hemoglobin) were found at the other dose levels. Pretreatment of animals with ascorbate (30 - 60 minutes before administering benzocaine) or simultaneous administration of varying amounts of ascorbate (up to 100 mg) failed to provide a protective effect during the period of observation (60 minutes) in animals receiving 3 or 6 mg benzocaine. Benzocaine does not induce methemoglobin formation in either incubated washed red cells or solutions of hemoglobin. Thus,the rapid formation of methemoglobin in intact animals suggests that the oxidant effect is caused by a metabolite of benzocaine. Washed red cells incubated in mixtures containing liver microsomes, benzocaine, and either NADH or NADPH were found to readily form methemoglobin, confirming notion that the oxidant is a biotransformation product of benzocaine. The relative rarity of benzocaine induced methemoglobinemia may be explained by overdosage rather than idiosyncratic response.
Genetic relatedness of multidrug-resistant Acinetobacter baumannii endemic to New York City.

SUMMARY Multidrug-resistant isolates of Acinetobacter baumannii from New York City generally belong to one of three ribotypes. To assess the accuracy of ribotyping, the relatedness of representative isolates was further assessed by rep-PCR, pulsed-field gel electrophoresis (PFGE), and DNA sequencing of five genes potentially associated with antimicrobial resistance {ampC, ompA, adeB, adeR, and abeM). The isolates fell into several major groups. The first group shared the same ribotype and had common mutations affecting OmpA, AdeR, and AbeM, but consisted of two subtypes with distinctive rep-PCR and PFGE patterns and ampC mutations. The second and third groups shared common alterations in OmpA, AdeR, and AbeM, but had distinct ribotype, rep-PCR, and PFGE patterns. The resistant isolates were unrelated to the ^-lactam susceptible isolates. Many of the resistant strains shared OmpA and AdeB patterns observed in several European clonal groups. Further development of a multilocus sequencing typing scheme will help determine if multidrug-resistant isolates from diverse geographic areas are indeed ancestrally related.
A front tracking method for a deformable intravascular bubble in a tube with soluble surfactant transport

Based on a front tracking scheme, we have presented a comprehensive algorithm for the study of a deformable bubble moving in a tube in the presence of a soluble or an insoluble surfactant. The emphasis here is on the dynamic adsorption of the soluble surfactant which non-linearly alters the surface tension, and this in turns affects the flow and transport in a complicated way. Furthermore, since a bubble-liquid interface is being examined, there is a need to accommodate a concentration jump across the interface in the evaluation of flow and transport. Standard numerical procedures need to be modified to accommodate this feature. Based on the physics governing the problem, an axisymmetric formulation is found to be adequate and is thus considered. The adsorption scheme for the soluble surfactant is carefully designed such that the total mass of the surfactant is well conserved, and the mass flux is accurately resolved by using an interface indicator function. This represents an advance in treating problems of this class. Tests on the efficacy of various aspects of the algorithm have been carried out. The algorithm has the flexibility of studying different models for adsorption/desorption and surfactant surface tension models, such as the Langmuir and the Frumkin models. These models have significant practical relevance. The numerical results obtained are qualitatively consistent with results where available. The results presented include an example of Marangoni flow which causes a bubble to propel out of its initial static location due to the development of a surface tension gradient. It is also shown that the bubble motion in Poiseuille flow may be significantly slowed down due to the presence of a soluble surfactant in the bulk medium. In that case, the Marangoni induced motion is in a direction opposite to that driven by the bulk pressure. Our study indicates that as the location of the adsorptive interface gets closer to the tube wall, the bulk fluid in the vicinity of the interface may become depleted of surfactant, an observation that has particular significance in understanding gas embolism and for developing therapeutic measures.
Speed-torque calculations for induction motors

THERE HAS recently been a renewed interest in the part-winding method of securing reduced starting current with moderate starting torque values for polyphase induction motors in sizes of 50 hp and larger. The most usual scheme is to provide the motor with two identical parallel circuits in the stator winding, and to connect only one of these circuits in each phase to the power supply for starting. After a brief interval, the remaining circuits are connected, and the motor then operates in a normal way.
Nitrogen and ammonia assimilation in the cyanobacteria: Regulation of glutamine synthetase

Abstract Glutamine synthetase, the first enzyme of the ammonia assimilatory pathway, has been purified from Anabaena sp. CA by use of established procedures and by affinity chromatography as a final step. No adenylylation system controlling glutamine synthetase activity was found. The enzyme shows a marked specificity for Mg 2+ in the biosynthetic assay and Mn 2+ in the transferase assay. Under physiological conditions, Co 2+ produces a large stimulatory effect on the Mg 2+ -dependent biosynthetic activity. The enzyme is inhibited by the feedback modifiers l -alanine, glycine, l -serine, l -aspartate, and 5′-AMP. Inhibition by l -serine and l -aspartate is linear, noncompetitive with respect to l -glutamate with apparent K i values of 3 and 13 m m , respectively. Cumulative inhibition is seen with mixtures of l -serine, l -aspartate, and 5′-AMP. The results indicate that, in vivo , divalent cation availability and the presence of feedback inhibitors may play the dominant role in regulating glutamine synthetase activity and hence ammonia assimilation in nitrogen-fixing cyanobacteria.
Adolescents’ Reports of Parental Engagement and Academic Achievement in Immigrant Families

The purpose of this study was to add to the understanding of the effects of perceived parental engagement on adolescents' academic achievement in immigrant families. Self-report data were collected from 1,245 adolescents in immigrant families from four high schools in Los Angeles County. The sample characteristics follow: 13-16 years old (M = 14.5); 58.9% female, 41.1% male; 57.5% Latino; 40.6% 1st generation youth (i.e., foreign born), 59.4% 2nd generation youth. After controlling for parental educational attainment, parental engagement variables were indirectly related to grades through youths' academic engagement. Multigroup SEM indicated some differences between genders, generational statuses, and ethnicities (Latinos versus others). Adolescents' perceptions of monitoring by mothers and fathers were indirectly related to grades through academic engagement. Perceived educational advice by mothers was indirectly related to grades through academic engagement for non-Latinos, boys, and 2nd generation youth. Perceived mothers' schoolwork help was positively related to adolescents' academic engagement in all the models (except 2nd generation youth), yet fathers' schoolwork help was significant only for girls and 2nd generation youth.
Detection and localization of harmful atmospheric releases via support vector machines

Background We present a Support Vector Machine (SVM) approach to the localization of hazardous particulate releases in an urban area using features constructed only from measurements obtained from a network of sensors.
Application of model predictive control and optimization methods to semiconductor manufacturing supply-side inventory replenishment

As the worldwide electronics market continues to grow, increased levels of agility are required to maintain competitiveness. Current methods of reacting to supply and demand variability are known to require high levels of inventory in manufacturing and warehouses. To improve the daily match between supply and demand profiles, mathematical methods are presented based on continuous model predictive control and optimization techniques similar to those that have been in use for decades in the process industry. Results from simulation using production data show the new controller's ability to meet fluctuating demand while dramatically reducing warehouse inventories
Cold activation of Na influx through the Na-H exchange pathway in guinea pig red cells.

Previous work showed that amiloride partially inhibits the net gain of Na in cold-stored red cells of guinea pig and that the proportion of unidirectional Na influx sensitive to amiloride increases dramatically with cooling. This study shows that at 37°C amiloride-sensitive (AS) Na influx in guinea pig red blood cells is activated by cytoplasmic H+, hypertonic incubation, phorbol ester in the presence of extracellular Cat2+ and is correlated with cation-dependent H+ loss from acidified cells. Cytoplasmic acidification increases AS Na efflux into Na-free medium. These properties are consistent with the presence of a Na-H exchanger with a H+ regulatory site. Elevation of cytoplasmic free Mg2− above 3 mm greatly increases AS Na influx: this correlates with a Na-dependent loss of Mg2−, indicating the presence of a Na-Mg exchanger.
Natural Control of the Citrus Mealybug

The introduction into California of certain natural enemies of the citrus mealybug ( Pseudococcus citri Risso) has apparently accomplished its control and brought the population to a very low point. The coccinellid beetle, Cryptolaemus montrouzieri Muls., and the hymenopterous parasite, Leptomastidea abnormis Gir., can be credited with the major part of this reduction of the citrus mealybug. The present paper gives a brief history of the pest in California and some observations on the predators and parasites present during the early outbreaks and continuing up through the year 1918. There is a rather complex interrelation of the various parasitic enemies, the most important of which are pictured on the accompanying chart.
Dressed to Rule: Royal and Court Costume from Louis XIV to Elizabeth II – By Philip Mansel

In this engaging enquiry, the author examines how rulers have used clothing to inspire respect, promote nationalism, and command obedience. Louis XIV's embrace of the multicolored, bejeweled habit ...
Corporate Ethics Officers And Government Ethics Administrators Comparing Apples With Oranges or a Lesson to Be Learned

As society enters the next millennium, ethics transgressions continue to make headlines. A Walker Research poll found 57% of public employees were aware of an ethical violation in the past 2 years. Similarly, an Ethics Officer Association-sponsored poll found that 48% of corporate employees admitted to unethical or illegal acts in 1996. Most governments have ethics boards or commissions, and corporations have ethics or compliance offices. Despite the existence of this ethics infrastructure, violations continue. What do these respective offices do? This article posits that there are important lessons to be learned by a cross-fertilization of knowledge between private sector ethics officers and public ethics administrators.
Growth and characterization of ZnSe single crystal by CVT method directly from elements zinc and selenium

The ZnSe single crystal with 8×7×0.8mm in size was grown directly from commercial grade high-purity elements, zinc(6N) and selenium(5N), by the CVT method. The chemical transport agent of (NH 4 ) 3 ZnCl 5 and the growth temperature of 1001~1005° C were employed. The ZnSe crystal shows only (111) face. The FWHM value of double crystal rocking curve of as-grown ZnSe slice was 50s due to the influence of free dendrite crystal microscope on the surface of ZnSe slice, which was in good agreement with the RO-XRD FWHM value of 48sec. The photoluminescence spectrum of the as-grown ZnSe crystal consists of a DAP emission and a broad SA luminescence band. The average etch pit density was about (5~8)×10 4 cm -2 . The infrared (IR) transmission spectra and ultraviolet absorption measurement indicated that the ZnSe single crystal has good crystalline perfection and high optical quality. All the results confirmed the superiority of this CVT growth method for ZnSe single crystal.
Increasing comorbidity with diabetes in the community: Diabetes research challenges

Abstract Background The purpose of this paper is to discuss the ongoing definitional, measurement and analytic challenges imposed on community-based diabetes researchers examining the experiences and outcomes of home-dwelling adults surviving longer with diabetes and additional comorbid health conditions. When selecting from the still limited number of standard hospital-oriented comorbidity methods, researchers across the world will need to consider a frequently complex series of methodological decisions from their enrolling such adults with increased comorbidity into study samples. Conclusions Three categories of methodological implications from increasing forms of comorbid diabetes are discussed for diabetes researchers. Six sequenced research design strategies with specific examples are offered regarding how to most rigorously incorporate elements of comorbidity into prospective diabetes study designs.
Modeling, identification and prediction of a class of nonlinear viscoelastic materials (II)

Abstract In this paper a nonlinear Volterra integral equation is used to characterize a class of nonlinear viscoelastic materials subject to uniaxial effects. A number of unknown parameters appearing in the mathematical structure of the model is optimally determined such as to minimize a least squares functional of all the experimental data, assumed to be given in terms of relaxation tests performed at various strain levels. The predictive ability of the model is tested using the experimental data furnished in [10]. The results are finally compared with those reported by Findley and Lai using a multiple integral model [9], [10] and with the experimental ones.
Partitioned Quasi-Newton Methods for Nonlinear Equality Constrained Optimization

We examine the nonlinear equality constrained problem (NEP) in a projected or partitioned form to reveal the basic structure of the Hessian matrix. The concepts of quasi-Newton methods are then introduced by considering unconstrained optimization problems. Drawing on this background, we present quasi-Newton methods for NEP and explore properties of the approximate Hessian matrix which insure good performance of Sequential Quadratic Programming (SQP) type algorithms: positivity, quasi-Newton relation, symmetry, and the least-change property. Current quasi-Newton methods and the strategies they use to provide these properties are then examined. Although it is particularly desirable to maintain positivity of the null-space projection of the Hessian matrix, we show that existing methods fail to do this in a simple and reliable manner. Consequently, our goal in this thesis is to find new updates which incorporate these desirable properties of the Hessian matrix. Using a variational approach, we derive several new quasi-Newton updates for NEP. These updates are derived using the partitioned forms of the Hessian matrix, allowing us to incorporate the desired properties for each partition. Two of the update formulas, the Lower Half Update (LHU) and the Partitioned BFGS Update (PBU), are shown to be particularly successful. The LHU and PBU formulas are of the least-change type and satisfy a standard quasi-Newton equation, retain symmetry of the full Hessian, and keep the null-space projection of the Hessian positive definite. In special cases, these new updates simplify to projected forms of the Broyden, Powell Symmetric Broyden, and Broyden-Fletcher-Goldfarb-Shanno formulas. These new updates are particularly attractive since they require only one gradient evaluation per iteration. They may be used at nearly every iteration, even when we are far from the solution, without requiring special line search conditions or step size restrictions. Next, we discuss implementation of the LHU and PBU formulas. In particular, we examine the cubic equation which must be solved at every iteration, its accurate solution, and the selection of the cubic root. We prove R-superlinear convergence and present extensive computational results including comparisons with existing quasi-Newton methods for the nonlinear equality problem.
Constructive approximations of spherical functions

Approximation of functions on the sphere arises in almost all applications modeling data collected on the surface of the earth and for reconstruction of various processes in spherical coordinates. Constructive approximation of high dimensional spherical functions are useful for approximation of processes of several variables on a compact subset of a Euclidean space by mapping the data onto the unit sphere of a space having one higher dimension, avoiding the boundary effect of the set. Interpolation operators on the circle and periodic domains (based on a class of basis functions and data values) are essential for many high performance simulations. These operators are represented by analytical summation formulas that can be computed very efficiently using the fast Fourier transform. This work is concerned with construction of a similar class of interpolation and quasi-interpolation operators on the unit sphere in ℝq, for q = 3, 4, 5, · · ·, using a new class of basis functions. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Ontogeny of the Immune System: Fetal Lamb as a Model

Summary: We examined adult sheep lymphocytes for the following surface markers: Surface membrane immunoglobulin, antigen identified by anti-sheep thymocyte globulin and complement receptors. We quantitated sheep peripheral blood mononuclear leukocyte proliferative responses to mitogens and alloantigens, and demonstrated a neutrophil-directed chemotactic factor (NLDCF) liberated by mitogen-stimulated sheep mononuclear cells. A comparison of adult and fetal sheep from 120-150 d of gestation demonstrated that I) fetal sheep had adult proportions of surface membrane Ig+ and T+ lymphocytes but a significant decrease in FcIgG receptor+ lymphocytes, 2) proliferative responses of fetal sheep blood mononuclear cells to mitogens and alloantigens were comparable to adult responses, and 3) fetal mononuclear leukocytes failed to produce the lymphokine, NLDCF, in response to mitogen stimulation.
Restick following initial Angioseal use.

The Angioseal hemostatic device is currently in widespread use for arterial closure after both diagnostic and interventional procedures. Resticking of the artery in which an Angioseal device has been placed has been discouraged for up to 90 days after the initial device placement because of theoretical concerns of disruption or dislodgment of the hemostatic plug. However, no data are available to address this concern. We evaluated the incidence of vascular complications following restick of the artery in which an Angioseal device had been deployed </= 90 days previously in 181 patients. Restick occurred 1-7 days after device placement in 80 patients, 8-30 days in 34 patients, and 31-90 days in 66 patients. There were no major bleeding, vascular repair, vessel occlusion, or embolizations. Three large hematomas (1.7%) were noted. These data suggest that restick can be performed safely after initial Angioseal deployment.
Computation of the biot drag and virtual mass coefficients

Abstract The Biot equations model the propagation of acoustic waves in fluid-saturated porous media. The equations contain coefficients which depend upon the frequency and the fabric, or microstructure, of the solid constituent. Recently, a method has been developed for determining the drag and virtual mass coefficients in Biot's equations as functions of frequency. The method requires solving for the motion of the fluid in the pores when the pore walls are subjected to a spatially uniform, oscillatory motion. To determine the fluid motion in realistic pore spaces, a numerical method must be used. In this paper the finite element method is used to determine the fluid motion. The drag and virtual mass coefficients are determined for several two-dimensional pore spaces. It is concluded that the drag coefficient is very insensitive to the pore geometry, while the virtual mass coefficient is sensitive to the pore geometry. It is also shown that the results can be expressed in nondimensional forms which permit the coefficients to be determined for different values of a characteristic linear dimension of the pore space.
Mitochondrial adaptations evoked with exercise are associated with a reduction in age-induced testicular atrophy in Fischer-344 rats

Mitochondrial dysfunction in various tissues has been associated with numerous conditions including aging. In testes, aging induces atrophy and a decline in male reproductive function but the involvement of mitochondria is not clear. The purpose of this study was to examine whether the mitochondrial profile differed with (1) aging, and (2) 10-weeks of treadmill exercise training, in the testes of young (6 month) and old (24 month) Fischer-344 (F344) animals. Old animals exhibited significant atrophy (30 % decline; P < 0.05) in testes compared to young animals. However, relative mitochondrial content was not reduced with age and this was consistent with the lack of change in the mitochondrial biogenesis regulator protein, peroxisome proliferator-activated receptor gamma coactivator 1-alpha and its downstream targets nuclear respiratory factor-1 and mitochondrial transcription factor A. No effect was observed in the pro- or anti-apoptotic proteins, Bax and Bcl-2, respectively, but age increased apoptosis inducing factor levels. Endurance training induced beneficial mitochondrial adaptations that were more prominent in old animals including greater increases in relative mtDNA content, biogenesis/remodeling (mitofusin 2), antioxidant capacity (mitochondrial superoxide dismutase) and lower levels of phosphorylated histone H2AX, an early marker of DNA damage (P < 0.05). Importantly, these exercise-induced changes were associated with an attenuation of testes atrophy in older sedentary animals (P < 0.05). Our results indicate that aging-induced atrophy in testes may not be associated with changes in relative mitochondrial content and key regulatory proteins and that exercise started in late-life elicits beneficial changes in mitochondria that may protect against age-induced testicular atrophy.
Glutathione enzyme and selenoprotein polymorphisms associate with mercury biomarker levels in Michigan dental professionals.

Mercury is a potent toxicant of concern to both the general public and occupationally exposed workers (e.g., dentists). Recent studies suggest that several genes mediating the toxicokinetics of mercury are polymorphic in humans and may influence inter-individual variability in mercury accumulation. This work hypothesizes that polymorphisms in key glutathione synthesizing enzyme, glutathione s-transferase, and selenoprotein genes underlie inter-individual differences in mercury body burden as assessed by analytical mercury measurement in urine and hair, biomarkers of elemental mercury and methylmercury, respectively. Urine and hair samples were collected from a population of dental professionals (n = 515), and total mercury content was measured. Average urine (1.06 {+-} 1.24 ug/L) and hair mercury levels (0.49 {+-} 0.63 ug/g) were similar to national U.S. population averages. Taqman assays were used to genotype DNA from buccal swab samples at 15 polymorphic sites in genes implicated in mercury metabolism. Linear regression modeling assessed the ability of polymorphisms to modify the relationship between mercury biomarker levels and exposure sources (e.g., amalgams, fish consumption). Five polymorphisms were significantly associated with urine mercury levels (GSTT1 deletion), hair mercury levels (GSTP1-105, GSTP1-114, GSS 5 Prime ), or both (SEPP1 3 Prime UTR). Overall, this study suggests that polymorphisms in selenoproteinsmore » and glutathione-related genes may influence elimination of mercury in the urine and hair or mercury retention following exposures to elemental mercury (via dental amalgams) and methylmercury (via fish consumption). -- Highlights: Black-Right-Pointing-Pointer We explore the influence of 15 polymorphisms on urine and hair Hg levels. Black-Right-Pointing-Pointer Urine and hair Hg levels in dental professionals were similar to the US population. Black-Right-Pointing-Pointer GSTT1 and SEPP1 polymorphisms associated with urine Hg levels. Black-Right-Pointing-Pointer Accumulation of Hg in hair following exposure from fish was modified by genotype. Black-Right-Pointing-Pointer GSTP1, GSS, and SEPP1 polymorphisms influenced Hg accumulation in hair.« less
Lateral asymmetry in human constitutive heterochromatin.

Human lymphocytes were grown for one replication cycle in BrdU, stained with 33258 Hoechst, exposed to UV light and subsequently treated with 2 x SSC and stained with Giemsa. This technique differentially stains the constitutive heterochromatin of chromosomes 1, 9, 15, 16, and the Y. In the heterochromatin of chromosome 9 both sister chromatids stained darkly and symmetrically but in the other four chromosomes the heterochromatin showed lateral asymmetry, one chromatid being darkly stained while its sister chromatid was as pale or paler than the rest of the chromosome. The lateral asymmetry is presumed to reflect an underlying asymmetry in distribution of thymine between the two strands of the DNA duplex in the satellite DNA component of the chromosomes. In some number 1 chromosomes compound lateral asymmetry was seen; darkly staining material was present on both sister chromatids although at any given point lateral asymmetry was maintained so that if one chromatid stained darkly the corresponding point on the sister chromatid was very pale. The pattern of compound lateral asymmetry varied among the number 1 chromosomes studied but was constant for any one homologue from one individual. This technique reveals a previously unsuspected type of polymorphism within the constitutive heterochromatin of man.
Modulation of phosphoinositide-protein kinase C signal transduction by omega-3 fatty acids: implications for the pathophysiology and treatment of recurrent neuropsychiatric illness.

Abstract The phosphoinositide (PI)–protein kinase C (PKC) signal transduction pathway is initiated by pre- and postsynaptic G α q-coupled receptors, and regulates several clinically relevant neurochemical events, including neurotransmitter release efficacy, monoamine receptor function and trafficking, monoamine transporter function and trafficking, axonal myelination, and gene expression. Mounting evidence for PI–PKC signaling hyperactivity in the peripheral (platelets) and central (premortem and postmortem brain) tissues of patients with schizophrenia, bipolar disorder, and major depressive disorder, coupled with evidence that PI–PKC signal transduction is down-regulated in rat brain following chronic, but not acute, treatment with antipsychotic, mood-stabilizer, and antidepressant medications, suggest that PI–PKC hyperactivity is central to an underlying pathophysiology. Evidence that membrane omega-3 fatty acids act as endogenous antagonists of the PI–PKC signal transduction pathway, coupled with evidence that omega-3 fatty acid deficiency is observed in peripheral and central tissues of patients with schizophrenia, bipolar disorder, and major depressive disorder, support the hypothesis that omega-3 fatty acid deficiency may contribute to elevated PI–PKC activity in these illnesses. The data reviewed in this paper outline a potential molecular mechanism by which omega-3 fatty acids could contribute to the pathophysiology and treatment of recurrent neuropsychiatric illness.
Responding to State Failure in Africa

Jeffrey Herbst's article, "Responding to State Failure in Africa,"' appeared most propitiously on the eve of the overthrow of the Mobutu dictatorship in Zaire. Two earlier articles by Herbst advanced a set of propositions that are relevant to his recent analysis. In "Migration, the Politics of Protest, and State Consolidation in Africa," using Albert Hirschman's Exit, Voice, and Loyalty, Herbst argued that the exit option of outward migration had largely closed in much of Africa.2 Other avenues of exit from the state such as the informal economy and the reduction of agricultural production were greatly overrated. Meanwhile, opportunities for voice through democratic political participation had been closed in most countries. Consequently, Africans resorted to migration to urban centers and violent protest as their main options, but neither of these effectively challenged the state. Herbst ends by suggesting that, since African peoples in distress could neither leave nor hide, at least one aspect of state consolidation, "control over population movements," could be said to be taking place. In "War and the State in Africa," Herbst's analysis is anchored to Charles Tilly's emphasis on the role of warfare in state building in Europe.3 In Africa there have been few interstate wars, and the prevailing African norm enshrined in the Organization of African Unity (OAU) has helped preserve the boundaries of states bequeathed by colonial rule, however nonviable they may be.4 Postcolonial Africa has consequently been denied the positive effects of the Darwinian process of survival of the fittest by which European states became consolidated through the defeat of frailer enemies, and from the concurrent enhancement of their military, administrative, revenue-collecting, and other capacities. Although Herbst treads carefully, his message is unambiguous: no
Renormalized (1σ) expansion for lattice animals and localization

The use of the (1/σ) expansion to calculate the thermodynamic properties of systems such as the Ising model or percolation whose diagrammatic expansion contains only diagrams with no free ends is reviewed. Here σ=z−1, where z is the coordination number of the lattice. For more general problems we formulate a selfconsistency condition for a site potential h, so that diagrams with free ends are eliminated. Construction of h gives the leading order in (1/σ) solution and is exact for the Cayley tree. We obtain correction terms by using a bond renormalized interaction so that to order (1/σ)5 we need only consider two-site problems. Results are given for (1) Kc, the critical fugacity for animals, when either H, the fugacity for free ends, or Q, the density of free ends, is fixed, and (2) (t/Ec), where Ec is the mobility energy and t is the magnitude of the hopping matrix element whose sign is random. At d=8 our results appear to be accurate to within about 0.01% for both animals and localization. We also obtain an expansion for Q(Kc)/(zKc) whose divergence near spatial dimensionality d=4 supports the idea that the order-parameter exponent β for lattice animals passes through zero at d=4.
Trends and fluctuations in the dates of ice break-up of lakes and rivers in Northern Europe: the effect of the North Atlantic Oscillation

Abstract The existence of an ice cover has important effects on the streamflow conditions as well as on the heat transfer between water bodies and the overlying atmosphere. This paper investigates the effects of climate variability on the termination of the ice season in the Baltic region. In particular, trends and fluctuations observed in the cryophenological records from this region are analyzed in detail, searching for possible connections with the North Atlantic Oscillation (NAO). The NAO seems to affect mostly the late-winter temperature (January–March) with a significant impact also on the mid-spring (April–May) period, when the air temperature is strongly correlated to the ice dates. A regional analysis shows the existence in the series of winter temperature (JFM) of the same fluctuations as the winter NAO. The same components can be found in the cryophenological records and (partly) in the series of spring temperature. Nevertheless, both ice phenology and spring temperature show the existence of a very well defined trend that is not detectable in the series of winter NAO at time scales of a century or longer. This leads to the conclusion that winter NAO has still a weak, though significant, effect on the regime of spring temperature in the Baltic region and explains the most significant fluctuating components embedded in the cryophenological records. However it is argued that other climatic forcings, related to CO 2 -induced regional and global warming, acting at the end of the ice season, are able to induce pronounced trends in the regime of spring temperature and have an important impact on the cryosphere leading to the earlier occurrence of ice break-up observed in the last several decades.
Efficient Silole-Based Organic Light-Emitting Diodes Using High Conductivity Polymer Anodes

High luminance organic light-emitting diodes (OLEDs) with a relatively low operating voltage are presented using a conducting polymer [without an indium−tin oxide (ITO) underlayer] as a hole-injecting electrode (anode) and silole derivatives as an emitter and/or an electron transporter. The conducting polymer films of poly(3,4-ethylenedioxythiophene)−poly(styrenesulfonate) were either spin-cast from aqueous dispersions on glass substrates or supplied as precoated films on poly(ethylene terephphalate) substrates. The films obtained by spin casting on glass substrates show very low sheet resistance (150 Ω/sq). OLEDs fabricated using this conducting polymer as an anode without using an ITO underlayer and CsF/Al as a cathode exhibit very low operating voltages (6.5 V at 1000 cd/m2). The silole derivative, 2,5-bis-(2‘,2‘ ‘-bipyridin-6-yl)-1,1-dimethyl-3,4-diphenylsilacyclopentadiene, used as an electron transporter, forms an Ohmic contact with the electron-injecting electrode (CsF/Al), leading to efficient ele...
Brain-Derived Neurotrophic Factor Promotes Long-Term Potentiation-Related Cytoskeletal Changes in Adult Hippocampus

Brain-derived neurotrophic factor (BDNF) is an extremely potent, positive modulator of theta burst induced long-term potentiation (LTP) in the adult hippocampus. The present studies tested whether the neurotrophin exerts its effects by facilitating cytoskeletal changes in dendritic spines. BDNF caused no changes in phalloidin labeling of filamentous actin (F-actin) when applied alone to rat hippocampal slices but markedly enhanced the number of densely labeled spines produced by a threshold level of theta burst stimulation. Conversely, the BDNF scavenger TrkB-Fc completely blocked increases in spine F-actin produced by suprathreshold levels of theta stimulation. TrkB-Fc also blocked LTP consolidation when applied 1-2 min, but not 10 min, after theta trains. Additional experiments confirmed that p21 activated kinase and cofilin, two actin-regulatory proteins implicated in spine morphogenesis, are concentrated in spines in mature hippocampus and further showed that both undergo rapid, dose-dependent phosphorylation after infusion of BDNF. These results demonstrate that the influence of BDNF on the actin cytoskeleton is retained into adulthood in which it serves to positively modulate the time-dependent LTP consolidation process.
Male Involvement for the Prevention of Mother-to-Child HIV Transmission: A Brief Review of Initiatives in East, West, and Central Africa

Current trends in HIV/AIDS research in sub-Saharan Africa (SSA) highlight socially and culturally sensitive interventions that mobilize community members and resources for universal access to HIV prevention, treatment, and care services. These factors are particularly important when addressing the complex social and cultural nature of implementing services for prevention of mother-to-child transmission of HIV (PMTCT). Across the globe approximately 34 % fewer children were infected with HIV through the perinatal or breastfeeding route in 2011 (est. 330,000) than in 2001 (est. 500,000), but ongoing mother-to-child HIV transmission is concentrated in sub-Saharan Africa, where fully 90 % of 2011 cases are estimated to have occurred. Recent literature suggests that PMTCT in Africa is optimized when interventions engage and empower community members, including male partners, to support program implementation and confront the social, cultural and economic barriers that facilitate continued vertical transmission of HIV. In resource-limited settings the feasibility and sustainability of PMTCT programs require innovative approaches to strengthening male engagement by leveraging lessons learned from successful initiatives in SSA. This review presents an overview of studies assessing barriers and facilitators of male participation in PMTCT and new interventions designed to increase male engagement in East, West, and Central Africa from 2000–2013, and examines the inclusion of men in PMTCT programs through the lens of community and facility activities that promote the engagement and involvement of both men and women in transformative PMTCT initiatives.
Overvaluation of body shape/weight and engagement in non-compensatory weight-control behaviors in eating disorders: is there a reciprocal relationship?

Background. Overvaluation of body shape/weight is thought to be the core psychopathology underlying eating disorders, which propels engagement in non-compensatory weight-control behaviors. In turn, these behaviors lead to binge eating and/or maintenance of low weight thereby reinforcing overvaluation. The present study investigated the reciprocal relationship between overvaluation and engagement in non-compensatory weight-control behaviors (defined in two ways: restrictive eating and compulsive exercise) among women diagnosed with anorexia nervosa or bulimia nervosa (N = 237). Method. Participants completed clinical interviews in which weekly eating disorder symptoms and behaviors were assessed over 2 years. Results. Overvaluation on a given week was associated with greater engagement in non-compensatory weight-control behaviors during the following week. Further, engagement in non-compensatory weight-control behaviors on a given week was associated with greater overvaluation during the following week. These findings held true regardless of participants’ shape/weight concerns (feelings of fatness and fat phobia), and eating disorder diagnosis. Conclusions. Our data provide empirical support for key aspects of the transdiagnostic cognitive-behavioral model of eating disorders and suggest that targeting non-compensatory weight-control behaviors in treatment may help alleviate overvaluation and shape/weight concerns.
Trimethoprim Once Daily vs. Nitrofurantoin in Treatment of Acute Urinary Tract Infections in Young Women, with Special Reference to Periurethral, Vaginal, and Fecal Flora

College women with acute urinary tract infections were assigned randomly to three groups: 110 received trimethoprim (TMP), 300 mg once a day for seven days (group 1); 104 received TMP, 200 mg once a day for 10 days (group 2); and 108 received nitrofurantoin, 100 mg four times a day for 10 days (group 3). All primary urinary pathogens were sensitive to TMP, and 98.8% were sensitive to nitrofurantoin. A satisfactory clinical response was achieved by the end of therapy in each group. Bacteriologic cures occurred in 100.0% of the TMP groups and 99.0% of the nitrofurantoin group by the end of therapy. By four weeks after therapy, bacteriologic cure rates were 87.0% in group 1, 93.0% in group 2, and 82.0% in group 3. Bacteria responsible for the recurrences remained sensitive to TMP and nitrofurantoin. Patients with positive and negative tests for antibody-coated bacteria had similar responses to therapy. After therapy there was minimal emergence of Enterobacteriaceae resistant to TMP or nitrofurantoin in the fecal and urogenital flora. Both TMP and nitrofurantoin were tolerated well and were effective for treatment of acute urinary tract infections in women.