cssi/SciSciGPT-SciSciNet huggingface dataset:
Roundtable: VH1's (White) Rapper Show: Intrusions, Sightlines, and Authority

This roundtable was held at the annual meeting of IASPM-US in Boston on April 28, 2007. It was sponsored by the IASPM-US Diversity Committee, and chaired by IASPM-US President Harry Berger. It was organized and edited by Deborah Wong. It addressed Ego Trip’s (White) Rapper Show, a reality show aired on VH1 between January and March of 2007. The roundtable participants included five scholar-activists who have each written extensively about hip-hop and racialization. The proceedings offered here are a set of composite texts: some of the panelists transcribed their spoken contributions to the roundtable, and several opted to publish written versions of their comments or edited versions of their spoken presentations. This published version of the roundtable thus offers the spirit of the live event and more. We are especially pleased that Miles White, who was unable to participate in the roundtable as planned, offered a written afterword included here. We thank audience member Richard Smith for taping the proceedings. We especially thank former President Harry Berger for chairing the roundtable and for establishing the Diversity Committee for IASPM-US in 2005.
Cluster ions in the electron and chemical ionization mass spectra of magnesium, mercury and lead acetates

Abstract This study documents the positive ion electron and chemical ionization mass spectra of magnesium, mercury and lead acetates. Of these three compounds, only magnesium acetate has been previously studied by electron ionization mass spectrometry. A characteristic feature in the electron ionization mass spectra of these compounds is the presence of cluster ions (ions with masses greater than that of the molecular ion) formed by reaction of stable ions with gas-phase, neutral molecules. The chemical ionization mass spectra of these compounds are reported here for the first time. In general, the chemical ionization mass spectra of these compounds contain cluster ions with relative abundances greater than observed in the electron ionization mass spectra, presumably as a result of collisional stabilization processes.
A New Model for Hadronization and $e^+ e^-$ Annihilation

Abstract A new string/cluster model for e+e− annihilation is presented. Event evolution is described using a simple, 3-stage formalism: (i) coherent parton shower generation, (ii) evolution of elementary strings formed from the parton final state, and (iii) parameterized hadronization of small mass clusters formed during string evolution. Significant improvements over previous cluster models arise from the use of full, massless relativistic string motion in the second stage of the model, so that the formalism is naturally insensitive to soft perturbative radiation. Parameter fitting and sensitivity of model predictions to variations in the cluster formation parameters are discussed in detail. The model is shown to reproduce a variety of e+e− annihilation data over a wide range of ECM. Specific suggestions are made for future improvements in the perturbative QCD and cluster decay stages of the model.
E9-Im9 colicin DNase-immunity protein biomolecular association in water: a multiple-copy and accelerated molecular dynamics simulation study.

Protein-protein transient and dynamic interactions underlie all biological processes. The molecular dynamics (MD) of the E9 colicin DNase protein, its Im9 inhibitor protein, and their E9-Im9 recognition complex are investigated by combining multiple-copy (MC) MD and accelerated MD (aMD) explicit-solvent simulation approaches, after validation with crystalline-phase and solution experiments. Im9 shows higher flexibility than its E9 counterpart. Im9 displays a significant reduction of backbone flexibility and a remarkable increase in motional correlation upon E9 association. Im9 loops 23-31 and 54-64 open with respect to the E9-Im9 X-ray structure and show high conformational diversity. Upon association a large fraction (∼20 nm 2 )o f E9 and Im9 protein surfaces become inaccessible to water. Numerous salt bridges transiently occurring throughout our six 50 ns long MC-MD simulations are not present in the X-ray model. Among these Im9 Glu31-E9 Arg96 and Im9 Glu41-Lys89 involve interface interactions. Through the use of 10 ns of Im9 aMD simulation, we reconcile the largest thermodynamic impact measured for Asp51Ala mutation with Im9 structure and dynamics. Lys57 acts as an essential molecular switch to shift Im9 surface loop towards an ideal configuration for E9 inhibition. This is achieved by switching Asp60-Lys57 and Asp62-Lys57 hydrogen bonds to Asp51-Lys57 salt bridge. E9-Im9 recognition involves shifts of conformational distributions, reorganization of intramolecular hydrogen bond patterns, and formation of new inter- and intramolecular interactions. The description of key transient biological interactions can be significantly enriched by the dynamic and atomiclevel information provided by computer simulations.
Toll-like Receptor 3 Activation Decreases Porcine Arterivirus Infection

Porcine reproductive and respiratory syndrome virus (PRRSV) is an RNA virus that initiates infection in pulmonary alveolar macrophages (PAMs), elicits weak immune responses, and establishes a persistent infection. To understand the role of dsRNA intermediates in eliciting host immunity, we sought to determine if toll-like receptor-3 (TLR3), a well-known dsRNA sensor, is involved in the regulation of PRRSV infection. TLR3 gene expression was increased in PAMs of congenitally infected 2-wk-old pigs. Stimulation of PAMs with dsRNA increased gene expression for TLR3 and interferon-beta and suppressed PRRSV infectivity. To investigate activation and signaling parameters, expression constructs of wild-type and functional-domain-truncated porcine TLR3 were used in cell transfection studies. When cells that overexpressed porcine TLR3 were stimulated with dsRNA a rapid and robust calcium influx was induced. Moreover, ligand activation of porcine TLR3 expressed in MARC-145 cells elicited an antiviral response to PRRSV. Conversely, transfection of PAMs with small-interfering RNA targeting porcine TLR3 resulted in up to 80% suppression of TLR3 mRNA expression and an increase in PRRSV infectivity. These data provide fundamental genetic and molecular information for porcine TLR3, and implicate its involvement in PRRSV infection, findings that may suggest new strategies to limit this costly pandemic disease.
The anticoagulant thrombin mutant W215A/E217A has a collapsed primary specificity pocket

Abstract The thrombin mutant W215A/E217A features a drastically impaired catalytic activity toward chromogenic and natural substrates but efficiently activates the anticoagulant protein C in the presence of thrombomodulin. As the remarkable anticoagulant properties of this mutant continue to be unraveled in preclinical studies, we solved the x-ray crystal structures of its free form and its complex with the active site inhibitor H-d-Phe-Pro-Arg-CH2Cl (PPACK). The PPACK-bound structure of W215A/E217A is identical to the structure of the PPACK-bound slow form of thrombin. On the other hand, the structure of the free form reveals a collapse of the 215-217 strand that crushes the primary specificity pocket. The collapse results from abrogation of the stacking interaction between Phe-227 and Trp-215 and the polar interactions of Glu-217 with Thr-172 and Lys-224. Other notable changes are a rotation of the carboxylate group of Asp-189, breakage of the H-bond between the catalytic residues Ser-195 and His-57, breakage of the ion pair between Asp-222 and Arg-187, and significant disorder in the 186- and 220-loops that define the Na+ site. These findings explain the impaired catalytic activity of W215A/E217A and demonstrate that the analysis of the molecular basis of substrate recognition by thrombin and other proteases requires crystallization of both the free and bound forms of the enzyme.
Adaptive scanning methodology for object-oriented visual information processing

The raster scan method in visual information processing is the rectangular pattern of image capture and reconstruction which systematically covers the area progressively, one line at a time starting from the top left corner. This traditional scanning method might work well for still image processing but for moving images, a scanning method such as diagonal snake scan can provide a better object correlation in a sequence of image frames. A novel adaptive scanning method for object-oriented visual information processing is proposed. Here, image pixels are collected starting from the centre of the image area and progressively extended outwards similar to the water drop ripple effect. Simulation results have shown that the proposed work uses up to 33% less processing time to cover the region-of-interest in an image compared to the raster scan method. Preliminary simulation results have also shown that with the proposed adaptive scanning methodology, there is a significant improvement in the performance of the object-oriented visual compression.
FACTORS AFFECTING POTASSIUM FIXATION AND CATION EXCHANGE CAPACITIES OF SOIL VERMICULITE CLAYS

Soil vermiculite clays of varying tetrahedral and octahedral composition and cation exchange capacity (CEC) were examined for their ability to fix K § in both the wet and dry states. Fixation capacity, expressed as per cent of the CEC, in the wet state was fairly high for most samples but it was enhanced greatly upon drying the K saturated samples. This enhancement indicated that each sample contained a number of vermiculite species with different CECs. The vermiculite clays, as a group, exhibited a much higher fixation capacity at a much lower CEC than those of the coarse grained vermiculites. This enhanced fixation is believed due to the diocta- hedral nature of the coarse grained vermiculites. In samples of nearly equal CECs only those con- taining AP § in tetrahedral positions exhibited an enhanced fixation capacity in the dry state but not in the wet state. In was remarkable to find that the state of oxidation of crystal structure iron strongly affected the fixation and the CEC. Reduction of Fe z+ to Fe z+ caused a decrease infixation even though the CEC increased as a result of this change. Conversely these reactions and their effects were found to be reversible. The variation in the orientation of the dipole of the hydroxyl ion in the octahedral layer with respect to the cleavage plane of the crystal is believed to be responsible for some of the noted differences.
Comments on: ‘Liquid Immiscibility and the Evolution of Basaltic Magma’ Journal of Petrology 48, 2187–2210

Veksler et al. (2007) have conducted a series of experiments that have led them to conclude that the evolving Skaergaard magma reached a two-liquid field near Middle Zone, much earlier than all previous studies have indicated. This conclusion is based on an incorrect extrapolation of questionable experimental results and is clearly inconsistent with evidence found in the field relations. The nature of late differentiates of the iron-rich Skaergaard magma has been a subject of considerable interest since they were first described by Wager and his co-workers (Wager & Deer, 1939, pp. 209^213; Wager & Brown, 1968, pp. 137^143). Three principal types of granophyre were recognized, as follows.
Quantitative Analysis of RNA-mediated Protein–Protein Interactions in Living Cells by FRET

Specific assembly of ribonucleoprotein complexes is essential in controlling various cellular functions including gene regulation. Diverse scaffolds containing proteins or nucleic acids could play key roles in stabilizing specific ribonucleoprotein complexes by enhancing protein-protein or RNA-protein interactions. One such example is the assembly of active RNA polymerase II transcription elongation complex originating from HIV-1 long terminal repeat promoter that involves HIV-1-encoded Tat protein and viral mRNA structure, trans-activation responsive RNA, and human CyclinT1 which is a subunit of the positive transcription elongation factor complex b. By using genetically encoded fluorescent proteins fused with Tat and human CyclinT1, here we demonstrate that human CyclinT1 was diffused throughout the nucleus and specific interactions between Tat and human CyclinT1 altered the localization of human CyclinT1 to specific nuclear foci. We also found that trans-activation responsive RNA enhanced protein-protein interactions between human CyclinT1 and Tat in living cells. Our results highlights the importance of trans-activation responsive RNA as a scaffold for stable and high affinity assembly of two protein partners to form a regulatory switch essential in HIV-1 gene regulation. RNA-mediated assembly of ribonucleoprotein complexes could be a general mechanism for stable ribonucleoprotein complex formation and a key step in regulating other cellular processes and viral replication. Furthermore, our results suggest that Tat interactions with human CyclinT1 change the nuclear location of positive transcription elongation factor complex b to modulate positive transcription elongation factor complex b function and transcription of cellular genes.
Efficacy of Aqueous and Alcohol-Based Quaternary Ammonium Sanitizers for Reducing Salmonella in Dusts Generated in Almond Hulling and Shelling Facilities

Large volumes of fine particulate matter or "dust" (soil, hulls, and shells) generated when hulls and shells are removed from almond kernels complicate cleaning and sanitation procedures in the huller-sheller (HS) environment. This study evaluated the efficacy of 3 aqueous quaternary ammonium sanitizers (AQuats) and an iso- propyl alcohol-based quaternary ammonium sanitizer (IPAQuat) for reducing Salmonella in dust collected from 2 HS facilities. Dust (1 g) was thoroughly mixed with 1 to 2 mL of inoculum (1 to 5 log CFU/g) before adding 1 to 7 mL of water, an AQuat (200 or 1000 ppm), or IPAQuat (200 ppm, 58.6% isopropyl alcohol) and incubated at 15 and 30 ! C for up to 21 d. At either 15 or 30 ! C increases in Salmonella populations in the dust were not significantly different following addition of either water or AQuats. No significant differences were observed upon water or AQuat addi- tion, either among the 3 AQuats tested, the concentration or volume of AQuat, or the initial level of Salmonella. When IPAQuat was added to dust inoculated at 1 to 7 log CFU/g, Salmonella levels were reduced to less than 1.3 log CFU/g after treatment and after incubation at 30 ! Cf or 48 h. IPAQuat was an effective sanitizer compared to the AQuats, even in the presence of high levels of organic material. Recent large-scale outbreaks of salmonellosis with low-moisturefoodshaveincreasedconcernsregardingtheirsafety.Littleresearchorguidanceisavailableonappro- priate cleaning and sanitationprograms for these food types. Thisresearch is focused on an evaluationof sanitation options for low-moisture foods, in particular almonds. The information should be applicable and useful to the nut industry and to other low-moisture foods. Practical Application: Recent large-scale outbreaks of salmonellosis with low-moisture foods have increased con- cerns regarding their safety. Little research or guidance is available on appropriate cleaning and sanitation pro- gramsforthesefoodtypes.Thisresearchisfocusedonanevaluationofsanitationoptionsforlow-moisturefoods,in particular almonds. The information should be applicable and useful to the nut industry and to other low-moisture foods.
An Alpha Motif at Tas3 C Terminus Mediates RITS cis Spreading and Promotes Heterochromatic Gene Silencing

RNA interference (RNAi) plays a pivotal role in the formation of heterochromatin at the fission yeast centromeres. The RNA-induced transcriptional silencing (RITS) complex, composed of heterochromatic small interfering RNAs (siRNAs), the siRNA-binding protein Ago1, the chromodomain protein Chp1, and the Ago1/Chp1-interacting protein Tas3, provides a physical tether between the RNAi and heterochromatin assembly pathways. Here, we report the structural and functional characterization of a C-terminal Tas3 α-helical motif (TAM), which self-associates into a helical polymer and is required for cis spreading of RITS in centromeric DNA regions. Site-directed mutations of key residues within the hydrophobic monomer-monomer interface disrupt Tas3-TAM polymeric self-association in vitro and result in loss of gene silencing, spreading of RITS, and a dramatic reduction in centromeric siRNAs in vivo. These results demonstrate that, in addition to the chromodomain of Chp1 and siRNA-loaded Ago1, Tas3 self-association is required for RITS spreading and efficient heterochromatic gene silencing at centromeric repeat regions.
A high-speed CMOS amplifier with dynamic frequency compensation

High-performance CMOS operational amplifiers with advanced frequency compensation, dynamic biasing, and enhanced slew rate are presented. Prototyping amplifiers with three design techniques have been fabricated by the MOSIS service using a 2- mu m scalable CMOS technology. Experimental results show a significant speed-up on amplifier transient responses. The dynamic biasing technique is used to enhance the slew rate by increasing the bias current of the input differential pair when the differential-mode input voltage is large. Another differential pair is added to sense the input voltage. The additional circuitry increases the input capacitance of an MOS amplifier, which can degrade power supply rejection ratio characteristics. Since the slew rate enhancement factor is proportional to the ratio of bias current and additional dynamic biasing current, a large improvement on slew rate always generates additional ripples on the power lines. >
Diagnosing heat and vorticity budgets of annual coupled rossby waves

Annual coupled Rossby waves are generated at the west coast of Australia and propagate westward across the eastern Indian Ocean from 10° to 30°S in covarying sea level height (SLH), sea surface temperature (SST), and meridional surface wind (MSW) residuals, generally traveling slower than uncoupled Rossby waves while increasing amplitude. The waves decouple in the western Indian Ocean as SST and SLH residuals become decorrelated, with wave amplitudes decreasing and westward phase speeds increasing. Here, the ocean and atmosphere thermal and vorticity budgets of the coupled Rossby waves in the eastern Indian Ocean along 20°S are diagnosed. In the upper ocean, these diagnostics find the residual SST tendency driven by the residual meridional geostrophic advection of mean temperature with warm SST residuals dissipated by upward latent heat flux to the atmosphere. In the troposphere, these upward latent heat fluxes drive mid-to-upper-level residual diabatic heating via excess condensation, balanced there by upward residual vertical thermal advection. The resulting upward residual vertical velocity drives residual upper-level divergence and lower-level convergence, the latter balanced in the troposphere vorticity budget by the residual meridional advection of planetary vorticity. This yields poleward MSW residuals collocated with warm SST residuals, as observed. The SLH tendency is modified by a positive feedback from wind stress curl residuals, the latter acting to increase the amplitude and decrease the westward phase speed of the wave. These diagnostics allow a more exact analytical model for coupled Rossby waves to be constructed, yielding wave characteristics as observed.
Human rights, politics, and reviews of research ethics

Although the human rights movement and the sphere of research ethics have overlapping principles and goals, there has been little attempt to incorporate external political and human rights contexts into research ethics codes or ethics reviews. Every element of a research ethics review--the balance of risks and benefits, the assurance of rights for individual participants, and the fair selection of research populations--can be affected by the political and human rights background in which a study is done. Research that at first seems to be low in risk may become high in risk if implemented in a country where the government might breach the confidentiality of study results or where results might be used to deport a refugee group. Researchers should determine whether research could or should be done by consulting human rights organisations and, when possible, a trusted colleague, to learn the background political context and human rights conditions of the settings in which they propose to do research.
Activities of Trovafloxacin and Ampicillin-Sulbactam Alone or in Combination versus Three Strains of Vancomycin- Intermediate Staphylococcus aureus in an In Vitro Pharmacodynamic Infection Model

The recent isolation of clinical strains of methicillin-resistant Staphylococcus aureus (MRSA) with intermediate susceptibility (MICs, 8 μg/ml) to vancomycin (vancomycin-intermediate S. aureus [VISA]) emphasizes the importance of developing novel antimicrobial regimens and/or agents for future treatment. We studied the activities of ampicillin-sulbactam and trovafloxacin alone or in combination against three unique strains of VISA in an in vitro infection model. Two VISA strains were trovafloxacin susceptible (MICs, ≤2 μg/ml); one VISA strain was trovafloxacin resistant (MIC, 4 μg/ml). Trovafloxacin was administered to simulate a dose of 200 or 400 mg every 24 h. Ampicillin-sulbactam was administered to simulate a dose of 3 g every 6 h. Samples were removed from the infection models over 48 h, and reductions in colony counts were compared between regimens. Trovafloxacin (200 mg) produced rapid killing of a control MRSA strain over the 48-h experiment but produced only slight killing of all three VISA strains. The higher dose of trovafloxacin improved killing but did not produce bactericidal activity at 48 h. Ampicillin-sulbactam produced rapid bactericidal activity against all four strains tested, and colony counts at 8 h were at the limits of detection. However, regrowth occurred by 48 h for each strain. The combination of ampicillin-sulbactam and trovafloxacin provided additive activity against two of the three VISA strains. In conclusion, trovafloxacin or ampicillin-sulbactam alone did not provide adequate activity against the VISA strains for the 48-h evaluation period, but the combination could help improve activity against some strains of VISA.
Inhibition of focal adhesion kinase (FAK) signaling in focal adhesions decreases cell motility and proliferation.

Abstract It has been proposed that the focal adhesion kinase (FAK) mediates focal adhesion formation through tyrosine phosphorylation during cell adhesion. We investigated the role of FAK in focal adhesion structure and function. Loading cells with a glutathione-S-transferase fusion protein (GST-Cterm) containing the FAK focal adhesion targeting sequence, but not the kinase domain, decreased the association of endogenous FAK with focal adhesions. This displacement of endogenous FAK in both BALB/c 3T3 cells and human umbilical vein endothelial cells loaded with GST-Cterm decreased focal adhesion phosphotyrosine content. Neither cell type, however, exhibited a reduction in focal adhesions after GST-Cterm loading. These results indicate that FAK mediates adhesion-associated tyrosine phosphorylation, but not the formation of focal adhesions. We then examined the effect of inhibiting FAK function on other adhesion-dependent cell behavior. Cells microinjected with GST-Cterm exhibited decreased migration. In addition, cells injected with GST-Cterm had decreased DNA synthesis compared with control-injected or noninjected cells. These findings suggest that FAK functions in the regulation of cell migration and cell proliferation.
Structural studies of the L-threonine-O-3-phosphate decarboxylase (CobD) enzyme from Salmonella enterica: the apo, substrate, and product-aldimine complexes.

The evolution of biosynthetic pathways is difficult to reconstruct in hindsight; however, the structures of the enzymes that are involved may provide insight into their development. One enzyme in the cobalamin biosynthetic pathway that appears to have evolved from a protein with different function is L-threonine-O-3-phosphate decarboxylase (CobD) from Salmonella enterica, which is structurally similar to histidinol phosphate aminotransferase (Cheong, C. G., Bauer, C. B., Brushaber, K. R., Escalante- Semerena, J. C., and Rayment, I. (2002) Biochemistry 41, 4798-4808). This enzyme is responsible for synthesizing (R)-1-amino-2-propanol phosphate which is the precursor for the linkage between the nucleotide loop and the corrin ring in cobalamin. To understand the relationship between this decarboxylase and the aspartate aminotransferase family to which it belongs, the structures of CobD in its apo state, the apo state complexed with the substrate, and its product external aldimine complex have been determined at 1.46, 1.8, and 1.8 A resolution, respectively. These structures show that the enzyme steers the breakdown of the external aldimine toward decarboxylation instead of amino transfer by positioning the carboxylate moiety of the substrate out of the plane of the pyridoxal ring and by placing the R-hydrogen out of reach of the catalytic base provided by the lysine that forms the internal aldimine. It would appear that CobD evolved from a primordial PLP-dependent aminotransferase, where the selection was based on similarities between the stereochemical properties of the substrates rather than preservation of the fate of the external aldimine. These structures provide a sequence signature for distinguishing between L-threonine-O-3- phosphate decarboxylase and histidinol phosphate aminotransferases, many of which appear to have been misannotated. The proteins required for the de novo synthesis of enzymatic cofactors such as hemes or cobalamin represent a substantial component of the genetic makeup of simple prokaryotes because of the chemical complexity of the pathways and the number of enzymes required to achieve total biosynthesis. At this point in time, the benefit that these cofactors provide far outweighs the biosynthetic cost; however, this raises the question of how these pathways evolved, especially since they arose very early in the development of life. It is widely accepted that enzyme evolution can occur via gene duplication followed by divergence of catalytic function
Temporary internal distraction as an aid to correction of severe scoliosis.

BACKGROUND: Halo traction is a well-recognized adjunct for correcting severe, complex, rigid scoliotic curves, but it is associated with complications and is contraindicated in the presence of fixed cervical instability, kyphosis, or stenosis. In addition, halo traction often requires prolonged hospital stays and is not welcomed by all families. These limitations led to consideration of temporary internal distraction as an alternative. METHODS: We retrospectively reviewed the records of children in whom severe scoliosis had been treated with temporary internal distraction. Our goals were to (1) assess whether the use of temporary internal distraction can aid in the correction of severe scoliosis and (2) identify complications associated with temporary internal distraction and compare them with those associated with halo traction. The mean preoperative curve was 104°. All patients underwent initial posterior release of the rigid portion of the spine (with six also having anterior release) and placement of spinal instrumentation under distraction during spinal cord monitoring. Of the ten patients, four had one distraction procedure (i.e., the initial surgery [or first distraction]) followed by definitive fusion and the remaining six had two distraction procedures (i.e., the initial surgery [or first distraction] followed by the second distraction) followed by definitive fusion. After distraction, all patients underwent posterior spinal fusion with definitive dual-rod fixation. The amount of correction was determined by measuring the curve on plain radiographs made preoperatively, after each internal distraction procedure, after definitive fusion, and at the time of final follow-up. RESULTS: Curve correction after use of internal distraction, and before definitive fusion, averaged 53% (from 104° to 49°) (range, 39% [from 70° to 43°] to 79% [from 70° to 15°]). This method facilitated safe, gradual deformity correction in all ten patients. The mean time between the initial procedure and the definitive fusion was 2.4 weeks. The mean final curve correction was 80% (from 104° to 20°) (range, 73% [from 131° to 35°] to 91% [from 110° to 10°]). No neurologic deficits or infections resulted. CONCLUSIONS: Temporary internal distraction is a viable alternative approach to maximizing curve correction in patients undergoing spinal fusion for severe scoliosis. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence. ORIGINAL ABSTRACT CITATION: “Temporary Internal Distraction as an Aid to Correction of Severe Scoliosis” (2006;88:[2035-41][1]). [1]: /lookup/volpage/88/2035
Estimating photoreceptor excitations from spectral outputs of a personal light exposure measurement device.

The intrinsic circadian clock requires photoentrainment to synchronize the 24-hour solar day. Therefore, light stimulation is an important component of chronobiological research. Currently, the chronobiological research field overwhelmingly uses photopic illuminance that is based on the luminous efficiency function, V(� ), to quantify light levels. However, recent discovery of intrinsically photosensitive retinal ganglion cells (ipRGCs), which are activated by self-contained melanopsin photopigment and also by inputs from rods and cones, makes light specification using a one-dimensional unit inadequate. Since the current understanding of how different photoreceptor inputs contribute to the circadian system through ipRGCs is limited, it is recommended to specify light in terms of the excitations of five photoreceptors (S-, M-, L-cones, rods and ipRGCs; Lucas et al., 2014). In the current study, we assessed whether the spectral outputs from a commercially available spectral watch (i.e. Actiwatch Spectrum) could be used to estimate photoreceptor excitations. Based on the color sensor spectral sensitivity functions from a previously published work, as well as from our measurements, we computed spectral outputs in the long-wavelength range (R), middlewavelength range (G), short-wavelength range (B) and broadband range (W) under 52 CIE illuminants (25 daylight illuminants, 27 fluorescent lights). We also computed the photoreceptor excitations for each illuminant using human photoreceptor spectral sensitivity functions. Linear regression analyses indicated that the Actiwatch spectral outputs could predict photoreceptor excitations reliably, under the assumption of linear responses of the Actiwatch color sensors. In addition, R, G, B outputs could classify illuminant types (fluorescent versus daylight illuminants) satisfactorily. However, the assessment of actual Actiwatch recording under several testing light sources showed that the spectral outputs were subject to great non-linearity, leading to less accurate estimation of photoreceptor excitations. Based on our analyses, we recommend that each spectral watch should be calibrated to measure spectral sensitivity functions and linearization characteristics for each sensor to have an accurate estimation of photoreceptor excitations. The method we provided to estimate photoreceptor excitations from the outputs of spectral watches could be used for chronobiological studies that can tolerate an error in the range of 0.2–0.5 log units. Our method can be easily expanded to incorporate linearization functions to have more accurate estimations.
AerR, a Second Aerobic Repressor of Photosynthesis Gene Expression in Rhodobacter capsulatus

Open reading frame orf192, which is located immediately upstream of the aerobic repressor gene crtJ, was genetically and biochemically demonstrated to code for a second aerobic repressor (AerR) of photosynthesis gene expression in Rhodobacter capsulatus. Promoter-mapping studies indicate that crtJ has its own promoter but that a significant proportion of crtJ expression is promoted by read-through transcription of orf192 (aerR) transcripts through crtJ. Disruption of aerR resulted in increased photopigment biosynthesis during aerobic growth to a level similar to that of disruption of crtJ. Like that reported for CrtJ, beta-galactosidase assays of reporter gene expression indicated that disruption of aerR resulted in a two- to threefold increase in aerobic expression of the crtI and pucB operons. However, unlike CrtJ, AerR aerobically represses puf operon expression and does not aerobically repress bchC expression. Gel mobility shift analysis with purified AerR indicates that AerR does not bind to a bchC promoter probe but does bind to the crtI, puc, and puf promoter probes. These results indicate that AerR is a DNA-binding protein that targets genes partially overlapping a subset of genes that are also controlled by CrtJ. We also provide evidence for cooperative binding of AerR and CrtJ to the puc promoter region.
Probability distribution of energetic-statistical size effect in quasibrittle fracture

The physical sources of randomness in quasibrittle fracture described by the cohesive crack model are discussed and theoretical arguments for the basic form of the probability distribution are presented. The probability distribution of the size effect on the nominal strength of structures made of heterogeneous quasibrittle materials is derived, under certain simplifying assumptions, from the nonlocal generalization of Weibull theory. Attention is limited to structures of positive geometry failing at the initiation of macroscopic crack growth from a zone of distributed cracking. It is shown that, for small structures, which do not dwarf the fracture process zone (FPZ), the mean size effect is deterministic, agreeing with the energetic size effect theory, which describes the size effect due to stress redistribution and the associated energy release caused by finite size of the FPZ formed before failure. Material randomness governs the statistical distribution of the nominal strength of structure and, for very large structure sizes, also the mean. The large-size and small-size asymptotic properties of size effect are determined, and the reasons for the existence of intermediate asymptotics are pointed out. Asymptotic matching is then used to obtain an approximate closed-form analytical expression for the probability distribution of failure load for any structure size. For large sizes, the probability distribution converges to the Weibull distribution for the weakest link model, and for small sizes, it converges to the Gaussian distribution justified by Daniels’ fiber bundle model. Comparisons with experimental data on the size-dependence of the modulus of rupture of concrete and laminates are shown. Monte Carlo simulations with finite elements are the subject of ongoing studies by Pang at Northwestern University to be reported later. q 2003 Elsevier Ltd. All rights reserved.
Discrete Dirac equation on a finite half-integer lattice

The formulation of the Dirac equation on a discrete lattice with half-integer spacing and periodic boundary conditions is investigated analytically. The importance of lattice formulations for problems in field theory and quantum mechanics is explained; the concept of half-integer Fourier representation is introduced; the discrete Dirac equation for the two-dimensional case is derived; dispersion relations for the four-dimensional case are developed; and the spinor formulation for the Dirac fields on the half-integer lattice and the discrete time variable for the four-dimensional time-dependent Dirac equation are obtained. It is argued that the half-integer lattice, because it takes the Dirac Lagrangian into account, is more than a mere relabeling of the integer lattice and may have fundamental physical meaning (e.g., for the statistics of fermions). It is noted that the present formulation does not lead to species doubling, except in the continuum limit.
Efficient point-counting on genus-2 hyperelliptic curves

This thesis presents an asymptotically fast algorithm to count points on typical genus-2 hyperelliptic curves over large prime fields Fp . Specifically, the algorithm takes time ≤ (1g p) 8 (lg lg p)1+o(1) and space ≤ (lg p)5(lg lg p)0+o(1). The algorithm has been implemented and, by computer experiments, demonstrated to work on randomly chosen examples. The previously fastest algorithm is due to Gaudry and Schost, improving upon a previous algorithm by Gaudry and Harley. The algorithm in this thesis has three important asymptotic improvements over the previous algorithms. The ideas used in this algorithm are also expected to be useful in practice. In very recent followup work, extending the work presented in this thesis and incorporating other ideas, Gaudry and Schost have successfully counted points on a genus-2 curve over a 127-bit prime field. Continued computations will eventually find a suitable curve to standardize for high-speed high-security genus-2 hyperelliptic-curve cryptography, specifically a secure Gaudry-form genus-2 hyperelliptic curve with small coefficients.
Trends in Pediatric Surgery Operative Volume among Residents and Fellows: Improving the Experience for All

Background The ACGME requires general surgery residents (GSR) to perform 20 pediatric surgery cases as part of the total 750 cases before graduation. Study Design We queried the ACGME General Surgery (1999 to 2014) and Pediatric Surgery (2003 to 2014) Case Logs for all pediatric operations performed during training. Means (±SD) and medians (10 th :90 th percentiles) were compared, and R 2 was calculated for all trends. Results The number of pediatric surgery fellows (PSF) increased 63% (23 to 39; R 2 = 0.82), while GSR numbers increased 12% (989 to 1,105; R 2 = 0.77). Total and average pediatric surgery case volume for GSR decreased from 39,309 to 32,156 (R 2 = 0.90) and 39.7 ± 13 to 29.1 ± 10 (R 2 = 0.91), respectively. Meanwhile, average PSF case volume increased from 980 ± 208 to 1,137 ± 202 (R 2 = 0.83). These trends persisted for inguinal/umbilical hernia (GSR 22.1 ± 13 to 15.6 ± 10; R 2 = 0.93; PSF 90.5 ± 17.6 to 104.4 ± 20.7; R 2 = 0.34), pyloric stenosis (GSR 3.9 ± 3 to 2.8 ± 3; R 2 = 0.60; PSF 29.6 ± 15 to 39.7 ± 16.8; R 2 = 0.69), and intestinal atresia (GSR 1.3 ± 2 to 1.1 ± 2; R 2 = 0.34; PSF 4.3 ± 4 to 11.8 ± 8; R 2 = 0.21). The mean number of GSR pediatric operations diminished for both junior (37.1 ± 20 to 27.3 ± 16; R 2 = 0.88) and chief (2.6 ± 5 to 1.7 ± 5; R 2 = 0.75) years. Teaching cases in pediatric surgery decreased at all levels. Although the percentage of GSR teaching cases performed during chief years fell modestly (6.6% to 4.7%; R 2 = 0.53), median teaching cases dropped from 2 (0:11 [10 th :90 th percentiles]) to zero (0:0 [10 th :90 th percentiles]). Mean PSF teaching cases declined (100.7 ± 396 to 44.5 ± 42; R 2 = 0.72), while the percentage of operations that were teaching cases decreased more sharply (10.3% to 3.5%; R 2 = 0.82). Conclusions Total pediatric surgery cases and PSF operative volume have increased, while GSR operative volume has decreased. Opportunities may exist to increase resident participation while providing further teaching opportunities for GSR, improving the quality of both resident and fellow training.
The evolution of stridulatory communication in ants, revisited

The presence and use of a stridulatory organ (SO) to produce vibrational signals is highly variable and structured within the ants. The file and scraper that make up the SO are specialized morphological features not used for functions other than stridulation (a vibratory signal production mechanism) and not found in non-stridulating species. It has been hypothesized and generally accepted that the stridulatory organ first evolved to alert nest mates of burial and need for rescue. Based on this premise, arboreal species are expected to exhibit a reduction of use of vibrational signals when compared to terrestrial species. Using ancestral state reconstruction, we have mapped the presence of the SO on a molecular phylogeny of the ants and found support for the hypothesis that the SO evolved multiple times in the ants. We quantitatively tested the hypothesis that stridulation evolved initially to signal burial/rescue by comparing the presence of the SO to general foraging and nesting preferences for 76 genera evenly spread throughout the currently accepted ant phylogeny. We found that a greater proportion of genera that are considered primarily arboreal possess a SO, as opposed to the ground nesting genera, and none of the five entirely subterranean genera included in this study possess a SO. We therefore reject the previous hypothesis regarding burial/rescue signaling.
Supplemental Bone Grafting in Giant Cell Tumor of the Extremity Reduces Nononcologic Complications

Background Giant cell tumors (GCTs) are treated with resection curettage and adjuvants followed by stabilization. Complications include recurrence, fracture, and joint degeneration. Studies have shown treatment with polymethylmethacrylate (PMMA) may increase the risk of joint degeneration and fracture. Other studies have suggested that subchondral bone grafting may reduce these risks.
Effects of particle alignment on the flow properties of an expandable mica in Na5P3O10 and K4P2O7 solutions

The mode of particle alignment in suspensions of an expandable mica (EM) has been investigated in the presence of sodium tripolyphosphate (STP) and potassium pyrophosphate (PPP) solutions. X-ray diffraction patterns of the suspensions at a STP to solids weight ratio between 0.3 and 0.7 were very sharp and analysis of these higher order reflections showed d-spacings between oriented clay mineral plates varying from 7.0 to 4.9 nm. The sharpness and high-order nature of the reflections indicate that the clay mineral particles arrange very regularly along the line perpendicular to the sheet to produce stacks with three-dimensional order. On the contrary, X-ray diffraction patterns of the clay mineral in PPP solutions did not show regular Bragg reflections, indicating no regular structure along a line perpendicular to the sheet. The flow behavior of the clay mineral in STP and PPP solutions was also radically different. The viscosity of suspensions in the presence of STP showed a decrease in viscosity consistent with particle alignment and three-dimensional stacking such that the apparent volume fraction of the suspension had reduced. In PPP solutions, the steady shear viscosity decreased initially but then showed rheopectic or shear thickening behavior at higher dose rates. The data are rationalized in terms of both the X-ray data and the interparticle force based on the DLVO theory which indicates that the clay mineral is present in a secondary minimum in STP solutions but in a primary minimum in PPP solutions. The rheology and X-ray data indicate that the clay mineral is forming stacks with two-dimensional order at high PPP concentrations in which the particles are linked together by a partial overlap of clay mineral plates to form a flat sheet. The role of the phosphate anion in the control of the alignment of clay mineral plates is thus seen to be highly dependent on the anion size and valency.
X-29A flight control system design experiences

The X-29A design experience has shown that relaxed stability can be beneficial to aerodynamic performance and yet not burden flight control requirements. Canard controlled aircraft, such as the X-29A, is shown to have characteristically lower static stability levels, yet do not require abnormally high surface rates for control. Included herein are discussions on the development of the X-29A flight control system, i ts control modes and corresponding digital control laws. Direct digital design, optimal control techniques are utilized to synthesize control laws. Handling quality criteria are introduced directly into the synthesis procedure and are verified via simulation.
Assembly of Large, High G+C Bacterial DNA Fragments in Yeast

The ability to assemble large pieces of prokaryotic DNA by yeast recombination has great application in synthetic biology, but cloning large pieces of high G+C prokaryotic DNA in yeast can be challenging. Additional considerations in cloning large pieces of high G+C DNA in yeast may be related to toxic genes, to the size of the DNA, or to the absence of yeast origins of replication within the sequence. As an example of our ability to clone high G+C DNA in yeast, we chose to work with Synechococcus elongatus PCC 7942, which has an average G+C content of 55%. We determined that no regions of the chromosome are toxic to yeast and that S. elongatus DNA fragments over ~200 kb are not stably maintained. DNA constructs with a total size under 200 kb could be readily assembled, even with 62 kb of overlapping sequence between pieces. Addition of yeast origins of replication throughout allowed us to increase the total size of DNA that could be assembled to at least 454 kb. Thus, cloning strategies utilizing yeast recombination with large, high G+C prokaryotic sequences should include yeast origins of replication as a part of the design process.
Original Research: Diametric effects of hypoxia on pathophysiology of sickle cell disease in a murine model:

Hypoxia causes erythrocyte sickling in vitro; however, its role in the pathophysiology of sickle cell disease is poorly understood. We report that hypoxia rapidly decreased oxygen saturation in transgenic sickle cell disease mice, but this effect was immediately buffered by a robust ventilatory response. The initial hypoxemia improved steadily throughout the duration of hypoxia without any detectable acute pulmonary adverse effect. Furthermore, the mice suffered acute anemia that ironically was associated with lowering of both plasma hemoglobin and heme. These results were corroborated by increased plasma haptoglobin and hemopexin levels. Markers of ischemic tissue injury increased spatiotemporally following repeated hypoxia exposures. This variation was supported by organ-specific induction of hypoxia-responsive genes. Our results show that hypoxia exerts diametric effects on sickle cell disease by promoting ischemic injury while enhancing the expression of hemolysis scavenger molecules. This phenomenon ...
Detection and isolation of minor lipid constituents

The use of thick layers of adsorbent for the concentration and subsequent isolation of neutral lipid constituents is described. Lipids not perceptible by conventional methods are demonstrated in concentrates of bovine heart extracts and identified as fatty aldehydes, O-alk-1-enyl diglycerides (neutral plasmalogens), and O-alkyl diglycerides (alkoxydiglycerides).
Analysis on monitoring results of chronic disease examination index among residents in Maojian District of Shiyan City

[Objective]To study the prevalence and risk factors of chronic diseases among residents in Maojian District of Shiyan City,provide scientific basis for developing the strategies and measures of chronic disease control and prevention.[Methods]The residents over 15 years old were randomly collected from 2 community health service centers that had the typical representativeness in geography,social economy and population structure,and a total of 500 residents were investigated(including 260 males and 240 females),to obtain the data of body weight,waist circumference,blood pressure and fasting blood-glucose.[Results]The average body weight was 61.65 kg,average waist circumference was 80.33 cm,average systolic pressure and diastolic pressure was 121.40 mm Hg and 78.39 mm Hg respectively,while the average fasting blood-glucose was 5.24 mmol / L.The rate of smoking(15.0%) and impaired fasting glucose or suspected diabetes(9.6%) in males were higher than those in females(1.2% and 3.3%),while the incidence rate of over weight in males(20.0%) was lower than that in females(30.0%),and the differences were significant(all P 0.01).[Conclusion]The sampling survey of chronic disease and its risk factors shows that the prevalence rates of hypertension and diabetes,which are related to lifestyle,are high in the Maojian District.