cssi/SciSciGPT-SciSciNet huggingface dataset:
Human mitochondrial holocytochrome c synthase’s heme binding, maturation determinants, and complex formation with cytochrome c

Proper functioning of the mitochondrion requires the orchestrated assembly of respiratory complexes with their cofactors. Cytochrome c, an essential electron carrier in mitochondria and a critical component of the apoptotic pathway, contains a heme cofactor covalently attached to the protein at a conserved CXXCH motif. Although it has been known for more than two decades that heme attachment requires the mitochondrial protein holocytochrome c synthase (HCCS), the mechanism remained unknown. We purified membrane-bound human HCCS with endogenous heme and in complex with its cognate human apocytochrome c. Spectroscopic analyses of HCCS alone and complexes of HCCS with site-directed variants of cytochrome c revealed the fundamental steps of heme attachment and maturation. A conserved histidine in HCCS (His154) provided the key ligand to the heme iron. Formation of the HCCS:heme complex served as the platform for interaction with apocytochrome c. Heme was the central molecule mediating contact between HCCS and apocytochrome c. A conserved histidine in apocytochrome c (His19 of CXXCH) supplied the second axial ligand to heme in the trapped HCCS:heme:cytochrome c complex. We also examined the substrate specificity of human HCCS and converted a bacterial cytochrome c into a robust substrate for the HCCS. The results allow us to describe the molecular mechanisms underlying the HCCS reaction.
New algorithms for the function T ( h,a ) of Owen, with application to bivariate normal and noncentral t -probabilities

The existing algorithm for the function T(h, a) of Owen performs well for small to moderate values of h, but becomes useless for larger h. In order to overcome this difficulty three new algorithms are developed. A function U(h, a), closely related to T, is introduced. It is especially useful for the computation of noncentral t-probabilities under odd degrees of freedom. For both T and U all four algorithms are compared and it is indicated which algorithm performs best in which (h, a)-region.
An Electrochemical System for Removing and Recovering Elemental Mercury from a Gas Stream

The impending EPA regulations on the control of mercury emissions from the flue stacks of coal-burning electric utilities has resulted in the development of numerous advanced mercury control technologies such as sorbent injection and in-situ mercury oxidation. Although these technologies can effectively remove mercury from a flue stack they share, along with many other technologies, the common shortcoming of intermedia pollution transfer i.e. the traffic of mercury from the air phase to the solid phase and the subsequent generation of residue for landfill. This work addresses the need for an integrated system of mercury removal and recovery from flue stack gases and from the environment. The research explored the capture of elemental mercury from the gas phase at ambient temperature on an electrically conductive porous sorbent. The mercury loaded sorbent was regenerated at the anode in an electrochemical cell and the oxidized mercury recovered at the cathode as solid elemental mercury. Activated carbon cloth was selected as the most suitable sorbent as it had the highest mercury adsorption capacity of the sorbents tested and was electrically conductive. Direct and indirect electro-oxidation were shown to remove 95% and 100%, respectively, of the elemental mercury from the carbon cloth. After regeneration the carbon cloth was reused without any loss in mercury adsorption capacity. More than 99% of the mercury stripped from the cloth during regeneration was recovered at the cathode.
Numerical Predictions of Combustion and Heat Transfer in a Packed Bed with Embedded Coolant Tubes

Abstract A model has been developed to simulate combustion and heat transfer in a porous matrix combustor-heater. The system consists of a packed bed in which a premixed natural gas-air mixture combusts. Radiative and convective heat transfer occurs from the flame zone to a fluid flowing through a bank of tubes embedded in the packed bed. Radiative heat transfer in the bed is modelled as a diffusion process, and the flow and temperature fields of the gas and solid matrix in the bed are calculated by solving the mass, momentum, energy and species conservation equations accounting for variations of thermophysical properties with temperature. Allowance is made for a finite heat transfer rate between the gas and the solid matrix, i.e., the temperatures of the gas and the solid matrix are not equal locally. The effects of particle diameter, excess air, and firing rate are examined and their influences on the thermal performance of the porous matrix combustor-heater are discussed. The sensitivity of the model t...
Combined modality treatment of Ewing's sarcoma of the maxilla.

Background. Primary bone sarcomas arising in osseous structures of the head and neck are rare. These tumors are often incompletely resected and treated with radiotherapy for local control. Methods. We report a case of a 9-year-old girl with a maxillary Ewing's sarcoma. This patient was successfully treated with neoadjuvant chemotherapy followed by surgical resection and prosthetic reconstruction of the primary site. The surgical approach that was used consisted of a subtotal maxillectomy by means of a facial degloving approach, sparing the orbital contents and the inferior orbital rim and orbital floor. Results. This approach produced excellent cosmetic, functional, and oncologic outcome. The patient remains without evidence of disease recurrence more than 4 years after surgery. Conclusions. This case illustrates a novel surgical approach to the resection of a maxillary Ewing's sarcoma and highlights the need for a multidisciplinary team approach to the management of head and neck sarcomas in children. © 2003 Wiley Periodicals, Inc. Head Neck 25: 168–172, 2003
American v. National Football League: Using public relations to "win" a war against a monopoly

Abstract No professional sports group ever achieved acceptance as widespread within a single decade's span as the American Football League (AFL). This study chronicles how the AFL used public relations strategies and tactics to garner public acceptance, which in turn helped convince the older National Football League (NFL) to merge with the upstart league. This study will further the understanding of how trade associations use public relations as an image-building device, as well as address a deficiency in the study of sports public relations.
Effective classification for crater detection: A case study on Mars

Craters are important geographical features caused by the impacts of meteoroids. Craters have been widely studied because they contain crucial information about the age and geologic formations of planets. This paper discusses an automated crater-detection framework using knowledge discovery and data mining (KDD) process including sampling, feature selection and creation, and supervised learning methods. The framework is evaluated on a real world case study of Mars crater detection. Compared with the existing method, the F detection rate is improved from 0.613 to 0.772 using a Martial site of area 451,562,500 m2
Ocular adnexal problems in craniofacial deformities

Summary Ocular adnexal problems occured in 86% (145) of 170 patients having major craniofacial reconstructive procedures at our medical centre in the past six years. Those without problems included certain minimal manifestations with craniofacial clefting phenomena. Evaluations were done by measurements and evaluation directly on the patient, life-size photographs, and cephalometric or 2 metre X-rays. Detailed ophthalmological evaluations were carried out on each patient. The syndromes were broken into six broad categories. These with the number of patients in parentheses were: orbital hypertelorism (24), craniofacial dysostosis (36), isolated craniofacial dysostosis or plagiocephaly (36), mandibulofacial dysostosis (10), hemifacial microsomia (24), and other deformities (40). Specific ocular adnexal problems related to the syndromes were evaluated. Vertical canthal displacement occurred in 66% of patients, horizontal canthal displacement in 33%, colobomas and coloboma-like conditions in 8%, nasolacrimal apparatus problems in 13%, ptosis in 15%, exorbitism in 14%, blepharophimosis in 1.7%, and palpebral fissure alterations in 53%. Certain problems tend to be most frequently associated with certain diagnoses. Vertical canthal displacement occurred in 100% (36/36) of patients with craniofacial dysostosis or its variants; there was also a high incidence of patients with isolated craniofacial dysostosis, and patients in the “other” classification category. Horizontal canthal displacement occurred in 100% of patients with orbital hypertelorism, and there was a high incidence of this in patients with craniofacial dysostosis. Colobomas and coloboma-like conditions occurred most consistently in orbital hypertelorism and mandibulofacial dysotosis. Nasolacrimal apparatus problems were most frequently associated with orbital hypertelorism and craniofacial dysostosis. Ptosis occured most consistently in craniofacial dysostosis, as did exorbitism. Methods for correction included several variations of known and newer techniques. Vertical canthal displacement up to 3 mm was corrected by displacing the lateral canthus through a coronal incision without preliminary dissection. Beyond 3 mm, preliminary dissection and orbital movement or bone grafts were necessary. Horizontal canthal displacement was best corrected utilizing preliminary dissection of the medial canthal ligament, and bone movements if the bony interorbital distance was more than 5 mm above normal. Colobomas, nasolacrimal apparatus problems, and ptosis were corrected by more standard ophthalmological procedures. Exorbitism was corrected by orbital advancement. Inadequately corrected ocular adnexal problems particularly in the canthal regions severely compromised the end result of the craniofacial procedure. Attention to their specific anatomical deformity and details of correction results in a high rate of success in handling these problems.
Thermochemical Analysis of the Stability of Continuous “SiC” Fibers

Continuous “SiC” fibers manufactured at present contain Si, C, O, and N, with an excess of free carbor. Thermodynamic calculations show that these fibers are inherently unstable when exposed to high temperatures. The fiber composition is expected to change, irrespective of the environment that it is exposed to, whether gaseous or condensed. The stability can be improved by replacing the free carbon with an excess of free silicon.
Gender Differences in Predicting Antisocial Behaviors: Developmental Consequences of Physical and Relational Aggression

This study investigated gender differences in the relationship of early physical and relational aggression to later peer rejection and overt and covert antisocial behaviors. Significant gender differences were found indicating physically aggressive boys were more likely than girls to experience later peer rejection. Early physical aggression was related to later overt antisocial behavior for boys and girls, and more strongly for girls than for boys. Early relational aggression was not associated with later forms of antisocial behavior. In the context of early physical aggression, for boys and girls peer rejection generally served to increment risk for later overt and covert antisocial behavior in an additive fashion. The data suggest some gender specificity in the social risk processes associated with the development of early overt and covert antisocial behaviors.
Feasibility of Promoting Smoking Cessation Among Methadone Users Using Multimedia Computer-Assisted Education

Background: The prevalence of smoking is very high among methadone users. As a method of delivering health education, computers can be utilized effectively. However computer-assisted education in methadone users has not been evaluated systematically. Objective: This study was aimed at assessing feasibility and patient acceptance of an interactive educational module of a multi-component smoking cessation counseling computer program for former illicit drug users treated in an outpatient methadone clinic. Methods: The computer-mediated education for hazards of smoking utilized in this study was driven by major constructs of adult learning theories. The program interface was tailored to individuals with minimal computer experience and was implemented on a touch screen tablet PC. The number of consecutive methadone-treated current smokers enrolled in the study was 35. After providing socio-demographic and smoking profiles, the patients were asked to use the educational program for 40 minutes. The impact of the computer-mediated education was assessed by administering a pre- and post-intervention Hazards of Smoking Knowledge Survey (HSKS). An attitudinal survey and semi-structured qualitative interview were used after the educational session to assess the opinions of participants about their educational experience. Results: The computer-mediated education resulted in significant increase of HSKS scores from 60.5 ± 16.3 to 70.4 ± 11.7 with t value 3.69 and P < .001. The majority of the patients (78.8%) felt the tablet PC was easy to use, and most of the patients (91.4%) rated the educational experience as good or excellent. After controlling for patient baseline characteristics, the effect of computer-mediated education remained statistically significant. Conclusions: Computer-assisted education using tablet PCs was feasible, well-accepted, and an effective means of providing hazards of smoking education among methadone users. [J Med Internet Res 2008;10(5):e33]
Assessment of Antihistamine Use in Early Pregnancy and Birth Defects

Background Several studies have reported an association between use of specific antihistamines in early pregnancy and certain specific birth defects. Objective To test 16 previously hypothesized associations between specific antihistamines and specific birth defects, and to identify possible new associations. Methods We used 1998-2010 data from the Slone Epidemiology Center Birth Defects Study, a multicenter case-control surveillance program of birth defects in North America. Mothers were interviewed within 6 months of delivery about demographic, reproductive, medical, and behavioral factors, and details on the use of prescription and nonprescription medications. We compared first trimester exposure to specific antihistamines between 13,213 infants with specific malformations and 6982 nonmalformed controls by using conditional logistic regression to estimate odds ratios and 95% confidence intervals (CIs), with adjustment for potential confounders, including indication for use. Results Overall, 13.7% of controls were exposed to antihistamines during the first trimester. The most commonly used medications were diphenhydramine (4.2%), loratadine (3.1%), doxylamine (1.9%), and chlorpheniramine (1.7%). When estimates were stable, none supported the previously hypothesized associations. Among more than 100 exploratory comparisons of other specific antihistamine-defect pairs, 14 had odds ratios ≥1.5, of which 6 had 95% CI bounds excluding 1.0 before but not after adjustment for multiple comparisons. Conclusion Our findings do not provide meaningful support for previously posited associations between antihistamines and major congenital anomalies; at the same time, we identified associations that had not been previously suggested. We suspect that previous associations may be chance findings in the context of multiple comparisons, a situation that may also apply to our new findings.
The effect of glutaraldehyde fixation on the primary photochemical processes in bacterial photosynthesis.

Abstract In Chromatium D the half-time for laser-induced (20–30-nsec flash) cytochrome C553 oxidation in redox poised chromatophores (1 μsec) and cytochrome C555 oxidation in whole cells (2.5μsec) is not affected by glutaraldehyde fixation. The reduction half-times for both cytochromes, however, increase as different functions of the glutaraldehyde concentration during the whole cell fixation process. At a cell-fixing concentration of 0.8%, cytochrome C555 but not C553 is observed after a laser flash. Steady light-induced spectra using similar preparations suggest the possibility of four components observable in the 500–620-nm range. These are cytochrome C555, P600, a species peaking at 560 nm and a component displaying a light-induced blue shift in the 500–540-nm region which may be a carotenoid response. The wavelength expected for the α-peak (reduced- minus -oxidized) of cytochrome cc′ is 560 nm, but the lack of a corresponding Soret peak makes identification uncertain and raises the possibility that we are observing a totally new component. Comparison of the amount of cytochrome oxidized by steady illumination and by a laser flash shows that on the average there are three cytochrome C555 molecules per reaction center in both whole cells and chromatophores. If the glutaraldehyde acts directly on the reaction center cytochromes then it is clear that cytochrome reduction requires large amplitude motion, but that oxidation does not. However, glutaraldehyde fixation may simply block the path of reducing electrons before they reach reaction center bound cytochromes.
Vehicle Path Verification Using Wireless Sensor Networks

In Path Verification, a verifier needs to determine how closely a mobile node's claimed path agrees with its actual path. We design a technique to leverage new or existing static wireless sensor networks to provide witness certificates to allow the verifier to compare actual paths with claimed paths of the vehicle as a notion of curve similarity. This is done by using Continuous Dynamic Time Warping to construct a manifold from the actual and claimed paths. The geodesic distance from the path origins to the path terminations over the surface of this manifold is analogous to the Frechet Distance between the paths. Using simulations and experiments on city streets, we demonstrate the performance of our technique. We also propose lightweight cryptographic techniques to mitigate security attacks.
Can we do better than dobutamine

The development of dobutamine, an infusible inotropic drug for heart failure, was first described in 1975. Although this sympathomimetic was designed to increase cardiac output, it is far from ideal as a long-term safe strategy. New drugs for acute heart failure are needed, and the successful development of new approaches will require diverse expertise and resources. In 1975, Tuttle and Mills1 published in Circulation Research an article entitled “Dobutamine: development of a new catecholamine to selectively increase cardiac contractility.” This work, having been cited >600 times, ranks 54th on the list of most cited articles from Circulation Research . Working at the Lilly Research Laboratories, a part of Eli Lilly, Tuttle, a pharmacologist, and Mills, a medicinal chemist, systematically modified the structure of isoproterenol/isoprenaline with the goal of generating new drugs to improve cardiac function. It was known that isoproterenol, through its action on β adrenergic receptors, could increase cardiac contractility but did so at the cost of increased heart rate and a concomitant proarrhythmic effect. Moreover, the increase in blood pressure that occurs with isoproterenol infusion was felt to be less desirable in ischemic heart failure. The goal was to devise a compound with a reduced risk of arrhythmia by identifying compounds with less effect on increasing heart rate than the parent compound isoproterenol. The clinical target for this drug design was ischemic heart failure because, at the time, there was little available to treat acute heart failure of any form, and ischemic heart failure was most common. In the process of modifying the structure of isoproterenol, dobutamine was identified and remains to this day, one of the few drugs available to treat acute heart failure. Albeit imperfect, dobutamine continues to be a mainstay in the management of acute congestive heart failure and has been for 35 years. …
Familial exudative vitreoretinopathy: surgical intervention and visual acuity outcomes.

• Background: Familial exudative vitreoretinopathy (FEVR) is a hereditary condition that may lead to vitreous hemorrhage and traction retinal detachment necessitating surgical intervention. In this paper we review the results of surgery on seven such patients (eight eyes). • Methods: Seven patients (eight eyes) were followed up after surgery that had been performed because of vitreous hemorrhage and/or traction retinal detachment due to FEVR, in an effort to evaluate outcomes. Parameters that were noted were the current age, gender, age at the time of first surgery, length of follow-up and postoperative retinal status and visual acuity. • Results: Seven patients (eight eyes) ranging in age from 6 months to 44 years with a mean of 24.7 and a median of 26 years were followed. There were three females and four males. The lowest age at which surgery was first performed was 6 months and the highest was 28 years, with a mean of 14.7 and a median of 17 years. Six of the 8 eyes were reattached following surgery, although some required multiple procedures. • Conclusion: Vitreoretinal surgery may be of benefit in helping to preserve some degree of vision in eyes of patients with FEVR who develop vitreous hemorrhage and/or retinal detachment.
Childhood Trauma History Differentiates Amygdala Response to Sad Faces within MDD

Objective Heightened amygdala reactivity to aversive stimuli in major depression is regarded as a core feature of the underlying physiology but individual differences in amygdala response may also arise secondary to persistent changes in limbic function during early neurodevelopment relative to stressors such as childhood trauma. We sought to determine whether heightened amygdala response is a core feature of depression or a general risk factor for psychopathology secondary to early life stress.
The impedance of a spherical monopolar electrode.

The impedance of a monopolar electrode immersed in an environmental volume conductor consists of two parts; the impedance of the active electrode-electrolyte interface, and the resistance of the environmental conductor. Two studies were carried out to quantitate these components. First, impedance-frequency data were collected for five spherical stainless-steel electrodes (ranging from 0.473 to 1.11 cm in diameter) immersed in 0.9% saline (ρ=70 Ω-cm). Impedance measurements were made from 100 Hz to 100 kHz and two sets of data were obtained; one before and one after each electrode was polished with fine emery paper. At low frequency, the measured impedances were high and varied with electrode surface preparation. However, above a transition frequency, the impedances were resistive, independent of the electrode surface preparation, and equal to ρ/2πd as predicted from the theory. This study indicates that the low frequency impedance of a monopolar electrode is dominated by the impedance of the electrode-electrolyte interface. Above a transition frequency, the resistance of the environmental conductor dominates, the value of this resistance depending on the electrode geometry and the resistivity (ρ) of the environmental conductor. A second study was conducted, to examine the effect of the distance to the indifferent electrode. A frequency (100 kHz) above the transition frequency was used and impedance data were collected for various distances between the monopolar and indifferent electrodes. The measured resistance increased asymptotically as the distance between the electrodes was increased. When the indifferent electrode diameter was at least 10 times the diameter of the spherical monopolar electrode, the measured resistance was within 5% of the value predicted for an indifferent electrode at infinity.
Sonar cross sections of bodies partially insonified by finite sound beams

An object that is partially insonified by a collimated sound beam may have a scattering cross section sometimes much larger than when the object is totally covered by the incident beam. We quantitatively study this partial insonification problem here, under the classical method of physical optics. The importance of this study stems from the fact that partial coverage of the target by the beam is the situation most likely to occur in many cases of practical importance. We consider several basic target shapes partially insonified by finite beams. These shapes include the spherical, the infinite and finite cylinder, the flat plate, and the capped sphere. High-frequency approximations of the resulting integrals, obtained by means of the saddle-point method, show the relative importance of the scattering centers located at the beam's specular reflection points, or at the edges of the spots that the beam shines on the scatterers. The physical-optics method is extended to obtain formulas for the bistatic cross sections of partially insonified objects. The results are numerically evaluated and graphically displayed in many pertinent instances and compared to the predictions of approaches, such as the Fresnel-zones method and the Geometrical Theory of Diffraction (GTD). The predictions of the physical-optics method have all the advantages and deficiencies of this method and, with very minor modifications, hold equally well for the partial illumination of objects by beams of electromagnetic radiation.
Two-Person Zero-Sum Games for Network Interdiction

A single evader attempts to traverse a path between two nodes in a network while a single interdictor attempts to detect the evader by setting up an inspection point along one of the network arcs. For each arc there is a known probability of detection if the evader traverses the arc that the interdictor is inspecting. The evader must determine a probabilistic "path-selection" strategy which minimizes the probability of detection while the interdictor must determine a probabilistic "arc-inspection" strategy which maximizes the probability of detection. The interdictor represents, in a simplified form, U.S. and allied forces attempting to interdict drugs and precursor chemicals as they are moved through river, road, and air routes in Latin America and the Caribbean. We show that the basic scenario is a two-person zero-sum game that might require the enumeration of an exponential number of paths, but then show that optimal strategies can be found using network flow techniques of polynomial complexity. To enhance realism, we also solve problems with unknown origins and destinations, multiple interdictors or evaders, and other generalizations.
Further characterization of a simple, automated exploratory model for the anxiolytic effects of benzodiazepines.

Anxiolytics specifically increase the number of exploratory transitions in a two-chambered model system for anxiety in mice. Characterization of parameters to optimize and standardize this model required analysis of multiple use of test animals, intertrial interval, and circadian variability. Time of day did not affect exploratory activity in mice treated with vehicle or diazepam between 10 a.m. and 11 p.m. Intertrial intervals of 1, 3, 5, or 7 days were equally effective. The diazepam-induced increase in exploratory activity was significant over the first three uses of test animals. These data recommend reuse of mice to a maximum of three trials, throughout the daytime or evening hours of their lighting schedule.
Havel-Hakimi residues of unigraphs

The residue r(G) of a graph G is the number of zeros left after fully reducing the degree sequence of G via the Havel-Hakimi algorithm. The residue is one of the best known lower bounds on the independence number of a graph in terms of the degree sequence. Though this bound may be arbitrarily weak for graphs in general, we show that if G is the unique realization of its degree sequence, then the independence number of G is either r(G) or r(G)+1, and we characterize the unigraphs corresponding to each value.
Coordinated Induction of the Ubiquitin Conjugation Pathway Accompanies the Developmentally Programmed Death of Insect Skeletal-Muscle

The developmentally programmed cell death of abdominal intersegmental muscles in the tobacco hawkmoth Manduca sexta is coincident with a 10-fold induction of the polyubiquitin gene as a hormonally regulated event (Schwartz, L. M., Myer, A., Kosz, L., Engelstein, M., and Maier, C. (1990) Neuron 5, 411-419). Solid phase immunochemical assays measuring intersegmental muscle pools of free and conjugated ubiquitin reveal that the induction of polyubiquitin mRNA is accompanied by a proportional increase in total ubiquitin polypeptide. Ubiquitin conjugate pools increase 10-fold at eclosion, during which loss of muscle protein mass is maximum. A smaller but measurable increase in ubiquitin conjugates is observed earlier in pupal development coincident with a modest enhanced degradation of myofibrillar proteins. Accumulation of ubiquitin conjugates is accompanied by induction in the pathway for polypeptide ligation, including the activating enzyme (E1), several carrier protein (E2) isoforms, and ubiquitin:protein isopeptide ligase (E3). Both accumulation of ubiquitin polypeptide and the enzymes of the conjugation pathway are subject to regulation by declining titers of the insect molting hormone 20-hydroxyecdysone, which signals onset of programmed cell death in the intersegmental muscles. Thus, programmed cell death within the intersegmental muscles is accomplished in part by stimulation of the ubiquitin-mediated degradative pathway through a coordinated induction of ubiquitin and the enzymes responsible for its conjugation to yield proteolytic intermediates. This suggests enzymes required for ubiquitin conjugation may represent additional genes recruited for developmentally programmed death.
Fractional sublimation of some metal chelates of thenoyltrifluoroacetone

Abstract Studies on the fractional sublimation of various metal β-diketone chelates have been extended to include the chelates of thenoyltrifluoroacetone (TTA). Many of the common metal chelates were found to be stable, to sublime readily, and to form well-defined zones in the vacuum fractional sublimator. Of the 17 chelates reported only those of manganese (II) and iron(II) were not volatile. The chelates of UO 2 (II), Zr(IV), Pb(II), and Cr(III) partially decomposed during sublimation and their recovery was incomplete. The recovery of the sublimed chelates of Ni(II), Mg(II), Al(III), Pd(II), Co(II), Cu(II). Fe(III), Tl(III), Zn(II) and Be(II) ranged from 87 to 100%, with most recoveries being quantitative. The sublimation recrystallization zone temperatures of the various chelates are compared to those of the metal acetylacetonates and the benzoyltrifluoroacetonates; in general, the metal chelates of TTA sublime more readily than those of benzoyltrifluoroacetone but are potentially less useful for fractional sublimation separations than the corresponding metal acetylacetonates. Even so, a quantitative separation of iron(III) from Ni(II), Al(III), Mn(II), and Fe(II) is proposed that depends upon the fractional sublimation of the TTA chelates.
Crystallization and preliminary X‐ray crystallographic analysis of phosphoribulokinase from Rhodobacter sphaeroides

A recombinant form of Rhodobacter sphaeroides phosphoribulokinase (PRK), expressed in Escherichia coli and isolated by affinity chromatography, was crystallized by the sitting drop vapor diffusion technique using NH4H2PO4 (pH 5.6) as the precipitating agent. PRK crystallizes in the cubic space group P432, with unit cell parameters a = b = c = 129.55 A. Based on the assumption of one 32-kDa monomer per asymmetric unit, the Vm value is 2.83 A3/Da. The octameric molecular symmetry is consistent with two planar tetramers stacked in a nearly eclipsed arrangement. A native data set has been collected to 2.6 A resolution.
Identification of a broad complex-regulated enhancer in the developing visual system of Drosophila.

group (but not in rbp or 2Bc mutants), the H217 ABSTRACT: During metamorphosis, the central enhancer is ectopically expressed in lamina precursor nervous system (CNS) is reconstructed through the cells (LPCs) whose proliferation is regulated by sig- concerted action of cell birth, death, and remodeling, so that it can serve the novel and complex behavioral nals from photoreceptor axons. As predicted by the needs of the adult insect. In Drosophila, Broad Com- current model of BRC structure-function relation- plex (BRC) zinc-finger transcription factors are es- ships, we demonstrated that BRC-Z2 isoforms, when sential for many aspects of metamorphosis, including induced during the third larval instar, can repress reorganization of the CNS. In particular, we showed H217 enhancer activity in the LPCs, whereas BRC- previously that some mutant alleles disrupt the assem- Z3 cannot. Taken together, the data suggest that the bly of visual system synaptic neuropils. Using an en- H217 P element has tagged an essential gene repressed hancer-detector screen, we have now identified a can- by BRC-Z2 in LPCs and required for the normal ar- didate BRC target gene, H217, that is normally ex- chitecture of the retinotopically connected visual pressed in visual system neural precursor cells of the system neuropils. q 1998 John Wiley & Sons, Inc. J Neurobiol inner proliferative center. Moreover, the P-element 34: 253-270, 1998 insertion in the H217 line has caused a hypomorphic Keywords: enhancer detector; transposon mutagene- mutation in an essential gene, with an optic lobe disor- sis; synaptic neuropil; neuroblast; optic lobes; meta- ganization phenotype very similar to that seen in BRC morphosis; broad mutants. In BRC mutants of the br complementation
Mutation screening of the UBE3A/E6-AP gene in autistic disorder.

Previous reports of individuals with autistic disorder with maternal duplications of 15q11-q13, 1-11 the Prader-Willi/Angelman syndrome region, suggest this area as a source of candidate genes in autistic disorder. Maternal truncation mutations in UBE3A, which encodes for E6-AP ubiquitin-protein ligase, have been shown to cause Angelman syndrome, 12,13 which can also result from the absence of maternal chromosomal material from this region. Despite showing no evidence for imprinting in other tissues, this gene was recently discovered to be preferentially maternally expressed in human brain 14,15 and expressed solely from the murine maternal chromosome in the hippocampus and cerebellar Purkinje cells, 16 regions implicated in the neuropathology of autism. 17-20 Based on this evidence, the coding region and a putative promoter region were sequenced in ten autistic subjects. Several polymorphisms were detected, but no evidence was found for a functional mutation. Evidence for likely altered regulation of UBE3A expression in maternal 15q11-q13 duplications suggests further investigation of the regulatory regions of this gene in autistic disorder.
On the determinant of elliptic differential and finite difference operators in vector bundles over $S^1$

For an elliptic differential operatorA overS 1, $$A = \sum\limits_{k = 0}^n {A_k (x)D^k } $$ , withA k (x) in END(ℂr) and θ as a principal angle, the ζ-regularized determinant Detθ A is computed in terms of the monodromy mapP A , associated toA and some invariant expressed in terms ofA n andA n−1 . A similar formula holds for finite difference operators. A number of applications and implications are given. In particular we present a formula for the signature ofA whenA is self adjoint and show that the determinant ofA is the limit of a sequence of computable expressions involving determinants of difference approximation ofA.
Face-selective Neurons During Passive Viewing and Working Memory Performance of Rhesus Monkeys: Evidence for Intrinsic Specialization of Neuronal Coding

The functional organization of prefrontal cortex (PFC) is a central issue in cognitive neuroscience. Previous physiological investigations have often failed to reveal specialization within the PFC. However, these studies have generally not been designed to examine this issue. Methodological issues such as statistical criteria for specificity, the number of neurons sampled, the extent of cortex sampled, and the number, location and nature of the stimuli used are among the variables that need to be considered in evaluating the results of studies on functional localization. In the present study, we have examined neurons in macaque monkeys trained to fixate while viewing visual stimuli, including faces, or to use them as memoranda on a working memory task. Visual responses of over 1500 neurons were recorded throughout a wide expanse of the PFC (areas 12, 9, 46, 8 and 45). Neurons were considered selective for faces if the best response to a face was over twice as strong as that to any of a wide variety of non-face stimuli. Full electrode track reconstructions in three monkeys revealed in each that neurons which met this criterion were concentrated almost exclusively in three distinct subregions within the projection region of the temporal lobe visual areas. We further show that for all neurons, the most visually selective neurons (for faces, objects or color patterns) were also the most concentrated in the temporal lobe recipient PFC. Similar face selectivity, regional specialization, and delay or delay-like activity were observed in monkeys whether trained on memory tasks or not, which suggests that these are naturally occurring properties of prefrontal neurons. These results confirm neuronal and regional specialization for information processing in PFC and elucidate how heretofore unexamined experimental variables have a strong influence on the detection of regional specialization.
Negotiating contract farming in the Dominican Republic.

This study analyzes the political and economic conditions that have fueled the rise of contract farming between peasant smallholders and agroindustrial firms in the Dominican Republic. Through a case study of tomato production, I illuminate the nature of contracting from the perspective of processing-firm officials and growers. I find that while processing firms pursue contracts to access peasant household land and labor, marginal producers turn to agroindustrial contracting to acquire credit and secure markets. My longitudinal analysis reveals how the ideological and material facets of the contract are continuously renegotiated in the context of changing production and market conditions. Ideological struggles revolve around the position of growers, who identify themselves as independent producers but who are viewed by firm officials as dependent employees, irrelevant landlords, and even idle tourists. Recent material struggles have centered on the distribution of pest-induced production losses, which hav...
Impacts of fiber orientation and milling on observed crystallinity in jack pine

Influences of fiber orientation and milling on wood cellulose crystallinity were studied using jack pine wood. The fiber orientation effects were measured by sampling rectangular wood blocks in radial, tangential, and cross-sectional orientations. The influence of milling was studied by analyzing the unsieved and sieved milled wood fractions (all <1,000 μm). Fiber orientation effect was manifested in both X-ray and Raman measurements and was dependent upon the orientation of the sampled wood blocks. In Raman, the observed crystallinity was similar between the blocks sampled on the tangential and the radial faces. However, the estimated values were 5.5 % lower compared to that measured in a powdered sample pellet. Moreover, in these sampling modes, the orientation of the block with respect to the direction of the electric vector of the laser made a difference only for the tangential mode of sampling. When a wood block was sampled on the cross-sectional face, the observed Raman crystallinity was 3.9 % higher from that of the pellet. The observed crystallinity did not significantly differ with change in sample orientation with respect to the electric vector direction. In contrast, the Segal-WAXS study of the blocks indicated that compared to the pellet, the estimated crystallinities in the radial, tangential, and cross-sectional sampling modes were 5, 2, and 11 % lower, respectively. This suggested that the radial and the tangential faces of the blocks can be used to estimate the crystallinity of wood. With regard to the effect of milling on Raman and Segal-WAXS estimates, the wood crystallinity did not depend upon the particle sizes of the fractionated samples and was similar to that of the original unfractionated ground wood.
Lethal Effects of Lambda-Cyhalothrin and its Commercial Formulation on Asian Longhorned Beetle (Coleoptera: Cerambycidae): Implications for Population Suppression, Tree Protection, Eradication, and Containment

We evaluated the 24-h contact toxicity of lambda-cyhalothrin for adult Asian longhorned beetle, Anoplophora glabripennis Motschulsky, by using topical application. Results showed that beetles are sensitive to lambda-cyhalothrin: the LD50 and LD90 were 0.13639 and 0.78461 µg/beetle, respectively. Residual activity of a commercial formulation of lambda-cyhalothrin was evaluated in a walking bioassay: Adult beetles walked across the surface of Denier bands treated with a series of concentrations of the formulation and exposed to the natural environment for 10, 20, 45, 69, and 90 d. Beetle mortality was recorded after 24 h. At the dosages of 150, 300, 450, and 600 mg/liter, residual activity declined slowly over the 90-d test period. All dosages provided 100% mortality up to 20 d posttreatment. No significant differences were detected in mortality among the dosages at each test interval until day 90 posttreatment, when the 450 and 600 mg/liter doses provided 100% mortality, which was significantly greater than percentage mortality provided by the 150 (20%) and 300 mg/liter (50%) doses. The 1200, 1500, and 1800 mg/liter doses provided 100% mortality for 158 d. The formulation may represent a new, alternative and complementary control strategy against A. glabripennis due to its high toxicity to adult A. glabripennis, its long residual activity, its rapid knock-down ability, and its potential use in specialized areas where current control strategies are not desirable or feasible.
Lymphomas of the Anterior Mediastinum

Lymphomas are the most common cause of masses in the pediatric mediastinum. More than 50% of children with lymphoblastic lymphoma present with an anterior mediastinal mass, and more than one third of all patients with non-Hodgkin's lymphoma have their primary sites in the mediastinum. Hodgkin's disease also frequently involves this anatomic compartment with approximately two thirds of all pediatric cases manifesting mediastinal adenopathy. Although surgical resection generally is not involved in the primary treatment of these diseases, surgeons often play a key role in obtaining adequate tissue for proper diagnostic analysis. Surgical access to the mediastinum often is required in the acquisition of a specimen.
Segmented Assimilation, Local Context and Determinants of Drug Violence in Miami and San Diego: Does Ethnicity and Immigration Matter?1:

Does the ethnic and immigrant composition of a community and existence of immigrant enclaves or barrios influence community level drug violence? This study explores the relationship between these and other factors in Miami and San Diego census tracts. We employ data about the distribution of Cubans, Central Americans, Haitians, Mexicans and Southeast Asians, controlling for social and economic influences of drug versus non-drug violence. We also analyze the impact of various waves of immigration and immigrant communities to understand the circumstances under which drug violence occurs or is limited at the census tract level. The findings lend some support to the positive and negative aspects of Portes and Rumbaut's (2001) segmented assimilation hypothesis in Miami and San Diego neighborhoods. The strength of this conclusion varies and is contingent upon ethnic composition, new versus old immigration, and the all-encompassing effects of economic deprivation
Very effective string model

Additional evidence is presented for a recently proposed effective string model, conjectured to hold throughout the parameter space of the basic 5 dimensional, triply charged black holes, which includes the effects of brane excitations, as well as momentum modes. We compute the low energy spacetime absorption coefficientσ for the scattering of a triplycharged scalar field in the near extremal case, and conjecture an exact form for σ. It is shown that this form of σ arises simply from the effective string model. This agreement encompasses both statistical factors coming from the Bose distributions of string excitations and a prefactor which depends on the effective string radius. An interesting feature of the effective string model is that the change in mass of the effective string system in an emission process is not equal to the change in the energies of the effective string excitations. If the model is valid, this may hold clues towards understanding back reaction due to Hawking radiation. A number of weak spots and open questions regarding the model are also noted.
Particle activation and droplet growth processes in condensation nucleus counter—I. Theoretical background☆

Abstract The heat and mass transfer, and droplet growth processes in a continuous flow condensation nucleus counter (CNC) have been studied numerically by solving the equations of convective heat and mass transfer, and the equation of vapor transfer to the growing droplets. The influence of sampling flow rate and the saturator and condenser wall temperatures have been studied. The thermophysical properties of the carrier gas have also been systematically varied to determine their influences on the performance of the CNC. Carrier gasses studied include air, argon and helium. Calculations have been made for conditions similar to those used in the commercially available CNC manufactured by TSI Inc. (model 3020). The results show that the constant supersaturation ratio isopleth in the condenser tube of the instrument has an elongated shape and the elongation is increased in the flow direction as the sampling flow rate is increased. This implies that the activation efficiency does not depend on the sampling flow rate, as long as the highest supersaturation region is within the condenser tube. A few per cent change in the condenser wall temperature or the saturator temperature does not have a great deal of effect on the performances of the counter. The droplet growth processes and its temperature variation have been predicted numerically for air, argon and helium as the carrier gas. The final droplet sizes in air and argon show a strong dependence on the initial nuclei sizes for ultra-fine aerosols, while a relatively small dependence is shown in the case of helium.