cssi/SciSciGPT-SciSciNet huggingface dataset:
Association of benzo(a)pyrene with dissolved organic matter: Prediction of Kdom from structural and chemical properties of the organic matter

Abstract The affinity of dissolved organic matter (DOM) for binding a polycyclic aromatic hydrocarbon, benzo(a)pyrene (BaP), was measured for 11 surface and ground waters and a commercial humic acid. The hydrophobic-acid (HbA) and hydrophobic-neutral (HbN) compositions of the DOM, solution absorptivity at 270nm (ABS 270 ), and DOM molar volumes were determined. Waters enriched in HbA material had a larger molar volume and higher aromatic content (as indicated by the ABS 270 ). There was a good correlation between the size and HbA content of the DOM from the different sources and the K dom for binding BaP. An excellent predictive relationship (r 2 = 0.9) was demonstrated between the ABS 270 of a water and the K dom for binding BaP. Based on these results, it is suggested that binding of BaP to DOM depends not only on the hydrophobicity of DOM, but also on the existence of an open structure within the DOM to provide access of the aqueous solute to hydrophobic domains within the DOM.
Sexually Dimorphic Effect of In Vitro Fertilization (IVF) on Adult Mouse Fat and Liver Metabolomes

The preimplantation embryo is particularly vulnerable to environmental perturbation, such that nutritional and in vitro stresses restricted exclusively to this stage may alter growth and affect long-term metabolic health. This is particularly relevant to the over 5 million children conceived by in vitro fertilization (IVF). We previously reported that even optimized IVF conditions reprogram mouse postnatal growth, fat deposition, and glucose homeostasis in a sexually dimorphic fashion. To more clearly interrogate the metabolic changes associated with IVF in adulthood, we used nontargeted mass spectrometry to globally profile adult IVF- and in vivo-conceived liver and gonadal adipose tissues. There was a sex- and tissue-specific effect of IVF on adult metabolite signatures indicative of metabolic reprogramming and oxidative stress and reflective of the observed phenotypes. Additionally, we observed a striking effect of IVF on adult sexual dimorphism. Male-female differences in metabolite concentration were exaggerated in hepatic IVF tissue and significantly reduced in IVF adipose tissue, with the majority of changes affecting amino acid and lipid metabolites. We also observed female-specific changes in markers of oxidative stress and adipogenesis, including reduced glutathione, cysteine glutathione disulfide, ophthalmate, urate, and corticosterone. In summary, embryo manipulation and early developmental experiences can affect adult patterns of sexual dimorphism and metabolic physiology.
THE EFFECTS of PLASTICIZERS ON CRYSTALLINITY, PERMEABILITY, and MECHANICAL PROPERTIES of METHYLCELLULOSE FILMS

The effects of plasticizers (polyethylene glycols [PEG] 400, 1,450, 8,000 and 20,000, glycerol [G] and propylene glycol [PG]), 30% dry basis, on the physical properties of methylcellulose (MC) films were investigated. With the exception of PG, plasticizers with low molecular weights (G and PEG 400) caused the largest increase in the d101 spacing of the crystal lattice. All plasticizers significantly (α= 0.05) increased oxygen (O2P) and water vapor permeabilities (WVP) of the films as compared to that of unplasticized MC, with PEG 400 having the greatest effect on O2P and G having the greatest effect on WVP. With the exception of PG, all plasticizers decreased the tensile strength of MC films, with PEG 400 causing the largest decrease. With the exception of PG and PEG 400, all plasticizers increased percent elongation values of MC films, with PEG 1,450 having the greatest effect. Glycerol and PEG were the most effective plasticizers for MC. the higher molecular weight plasticizers do provide some plasticizing properties and may be more suitable for applications that require a lower permeability to water vapor than can be achieved with glycerol.
Freeze-drying of solutions of serum albumin containing dimethylsulfoxide.

Abstract : Although several publications have emphasized the inadvisability of drying biologic materials containing dimethylsulfoxide (DMSO) by sublimation of ice in vacuo, the current studies showed a relationship to exist between the relative concentrations of serum albumin, human, and dimethylsulfoxide for successful or unsuccessful freeze-drying of albumin-DMSO solutions. The cycle of freeze-drying for the successful drying of an albumin-DMSO solution was a modification of the cycle used for the successful drying of suspensions of measles virus by sublimation of ice in vacuo. Using nuclear magnetic resonance spectroscopy, a strong, sharp signal for DMSO was obtained in preparations of freeze-dried albumin-DMSO solutions rehydrated with deuterium oxide, D2O.
Sex and hedgehog: roles of genes in the hedgehog signaling pathway in mammalian sexual differentiation.

The chromosome status of the mammalian embryo initiates a multistage process of sexual development in which the bipotential reproductive system establishes itself as either male or female. These events are governed by intricate cell–cell and interorgan communication that is regulated by multiple signaling pathways. The hedgehog signaling pathway was originally identified for its key role in the development of Drosophila, but is now recognized as a critical developmental regulator in many species, including humans. In addition to its developmental roles, the hedgehog signaling pathway also modulates adult organ function, and misregulation of this pathway often leads to diseases, such as cancer. The hedgehog signaling pathway acts through its morphogenetic ligands that signal from ligand-producing cells to target cells over a specified distance. The target cells then respond in a graded manner based on the concentration of the ligands that they are exposed to. Through this unique mechanism of action, the hedgehog signaling pathway elicits cell fate determination, epithelial–mesenchymal interactions, and cellular homeostasis. Here, we review current findings on the roles of hedgehog signaling in the sexually dimorphic development of the reproductive organs with an emphasis on mammals and comparative evidence in other species.
Hormonal risk factors and invasive epithelial ovarian cancer risk by parity

Recent studies have suggested that several ovarian cancer risk factors differ by parity status, but these findings have not been confirmed. We evaluated whether known risk factors of ovarian cancer differ between nulliparous and parous women using data from two large prospective cohorts. Data from the National Institutes of Health-AARP Diet and Health Study and the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial were combined for this analysis. Cox regression models were used to estimate associations with ovarian cancer risk. Risk heterogeneity by parity status was assessed using likelihood-ratio tests. Among the 125 437 women included in the analysis, there were 16 589 (13%) nulliparous women and 108 848 (87%) parous women. Of the 623 women diagnosed with invasive epithelial ovarian cancer, 102 (16%) were nulliparous and 521 (84%) were parous. While parity reduced ovarian cancer risk, no differences were found for other risk factors by parity. Among ever users of hormone therapy, body mass index suggestively increased the risk of ovarian cancer by 1.5-fold in nulliparous but not parous women (P-heterogeneity=0.08). While nulliparous women have higher ovarian cancer risk than parous women, our findings suggest that the relative effects of most other risk factors do not differ by parity.
The sigma-70 subunit from Escherichia coli C differs from that of E. coli K-12

The nucleotide sequence of the rpoD gene (encoding the primary sigma-70 (sigma 70) subunit of RNA polymerase) from Escherichia coli C was determined. This gene differs from that of E. coli K-12 by a 30-bp deletion and five single-bp substitutions, resulting in a sigma 70 subunit with three amino acid (aa) changes and a deletion of ten acidic aa.
The structure-activity relationship of DDT analogs in crayfish giant axons

Abstract The effects of 14 DDT analogs on the resting and action potentials of the crayfish giant axon were investigated using the intracellular microelectrode technique. These analogs can be classified into three groups, excitatory, blocking, and dualist. An excitatory analog tends to increase the excitability of the axonal membrane, and has hydrophobic side chains on the para positions whose optimal size equals that of the ethoxy group. A blocking analog suppresses the action potential without affecting the resting potential, and has hydrophilic side chains capable of forming hydrogen bonds. A dualist has both excitatory and blocking actions, and the latter may be related to restriction in rotation imposed by the grouping on the benzylic carbon. However, the dividing lines between these categories are not sharp, the compounds tending to fall along a spectrum between pure excitatory and pure blocking activity.
Pathologic findings in clinical stage A2 prostate cancer. Relation of tumor volume, grade, and location to pathologic stage

Transurethral resections (TUR) and totally embedded radical prostatectomies from 39 clinical Stage A2 prostate cancers were morphometrically analyzed and compared with 56 prior similarly studied clinical Stage B cancers. All the clinical A2 radical prostatectomies contained residual tumor with 26% having capsular penetration. Clinical Stage A2 tumors were much more heterogeneous than clinical Stage B tumors with respect to tumor location, grade, and amount. In particular, many clinical A2 cases were predominantly central or central and anterior in location (59%) and low-grade compared with clinical Stage B cases where most lesions were posterior, peripheral, and intermediate grade. Percent of tumor in TUR best predicted final pathologic stage versus TUR grade or volume. Despite statistically significant correlations between tumor percent and/or grade on TUR and final stage, predictability of final stage for individual patients from TUR data was poor. The complex interrelation of tumor location, grade, and amount resulted in wide and overlapping ranges for these parameters for organ-confined and nonconfined cases.
Evaluation of Preventative Adulticide Treatments for Control of Whitefringed Beetles

Carbaryl treatments based on timed and threshold schedules were directed against adults of Graphognathus spp. in peanuts. Threshold treatments, applied when adult populations reached 2 per 10 plants (5 total applications), were as effective in reducing the establishment of larval population as weekly seasonal treatments (15 applications) against adults. Adult populations averaging 2.3 per 10 plants in July, 7.5 per 10 plants in August, and 4.2 per 10 plants in September did not produce an economically damaging larval population. Fall larval populations of 35.2 per 9.3 dm2 of soil and subsequent spring populations of 4.3 per 9.3 dm2 did not significantly reduce stands of rye and peanuts.
Kinetics Study of the Photocleavage of (Coumarin-4-yl)methyl Esters

Photolabile coumarinylmethyl esters of biomolecules (caged compounds) are new tools for studying spatial and time-dependent aspects of signal transduction in living cells. Herein we describe a fluoresence spectroscopic method for the determination of the rate constants of the photolysis steps of such caged compounds using (6.7-dimethoxycoumarin-4-yl)methyl diethyl phosphate (DMCM-DEP) and sodium (6,7-dimethoxycoumarin-4-yl)methyl sulfate (DMCM-S). DMCM-DEP and DMCM-S are caged compounds which photorelease a proton, the corresponding acid anion, and the strongly fluorescent alcohol DMCM-OH upon excitation. The results of stationary and time-resolved measurements of the photochemistry and the luminescence of both caged compounds indicate that DMCM-OH is produced already during the excitation pulse. The quantitative analysis of the data demonstrates that the first step of the reactionheterolytic bond cleavage of the coumarinylmethyl ester leading to the ion pair of a DMCM cation and an acid anionis very fast...
Sleep duration versus sleep insufficiency as predictors of cardiometabolic health outcomes

Objective The objective of the present study was to investigate the relationship between sleep insufficiency and sleep duration, particularly regarding negative cardiometabolic health outcomes already considered to be affected by reduced sleep time.
Modelling the butterfly visual pathway

Abstract An electrophysiological investigation of visual mechanisms in the neotropical butterfly Morpho amathonte centralis was undertaken. An analysis of retinal potentials, recorded with microelectrodes, indicates the presence of three types of photoreceptor cells, responding maximally to blue (428 nm), green (483 nm) and yellow (564 nm). An extensive analysis of visual interneurons revealed ten major categories. Each of these was studied with reference to its spectral efficiency, changes with light adaptation, latency, and responsiveness to movement. It was found that none of the interneurons displayed a spectral efficiency comparable to the sum of receptor sensitivities. Rather, it appeared that the various interneurons demonstrated a special association with one or more of the types of photoreceptors. This was particularly apparent in the case of a series of wavelength-specific ‘colour fibres’ which were excited by blue light, and inhibited by longer wavelengths. Based upon this information it was possible to produce a ‘physiological’ model of the major mechanisms, characteristic of the Morpho visual pathway. This was reduced to its functional equivalent, by producing an electrical analogue. It is suggested that such techniques are as viable an approach to understanding the function of the visual pathway as are the commonly employed systems-analysis type of study.
Reactive Compatibilization of Polypropylene and Nylon

Abstract Studies have been carried out on the compatibilization of polypropylene and nylon using maleic anhydride grafted polypropylene (Polybond™ 3002). Solution and FTIR studies on the resin indicated that the compatibilizer reacted with nylon. The usefulness of the compatibilizer has been demonstrated for the recycling of shredded industrial carpet waste containing polypropylene and nylon. The mechanical properties and morphology of the extruded resin from carpet are reported.
A semi-quantitative reasoning methodology for filtering and ranking HAZOP results in HAZOPExpert

Abstract Hazard and Operability (HAZOP) analysis is the most widely used and recognized as the preferred Process Hazards Analysis (PHA) approach in the chemical process industry. Recently, a diagraph-model based framework and an expert system called HAZOPExpert was developed for automating this analysis. Upon testing the performance of the system on various industrial case studies. HAZOPExpert was found to successfully mimic the human expert's reasoning and identify the hazards. But, with the increasing complexity of the processes, the HAZOPExpert system generated a large number of consequences compared to those identified by a team of experts. This is mainly due to the strict qualitative reasoning approach implemented in the HAZOPExpert system. In order to filter and rank the consequences generated by the HAZOPExpert system, a semi-quantitative reasoning methodology is proposed using additional quantitative knowledge in the form of design and operating specifications of the process units, and process material property values. This filtering approach combines the qualitative digraph-based HAZOP models and the quantitative knowledge to eliminate the unrealizable consequences. Significant reduction in the number of consequences was obtained using this approach on an ethylene process plant HAZOP case study.
Linking tree form, allocation and growth with an allometrically explicit model

Abstract The influence of stem allometry on tree growth is explored with a simple model which projects growth for the idealized case where crown proportions, leaf properties and light use efficiency are held constant throughout growth. Here, the tree is regarded as a machine that grows itself by using light energy to synthesize biomass, which is in turn partitioned among its parts so as to maintain a specified allometry. The following model variants were considered. (1) The base case, which approximates a forest-grown tree, shows that the requirement that basal trunk diameter Db ∝ H1.5 (where H is total tree height), to prevent buckling, substantially slows the height growth rate with increasing tree size, as is observed in real trees. (2) The isometric tree, which maintains geometric similarity, such that Db ∝ H, has a nearly constant height growth rate, attaining 40 m in 1/3 of the time required for the more realistic, base case tree. (3) The “seedling tree”, which maintains constant leaf/stem mass (that of a seedling), requiring that Db ∝ H0.5, grows exponentially throughout life, attaining 40 m in 1/20 of the time required for the base case. (4) The “leech tree”, which reconfigures its branches, leaves and roots as it grows, rather than turning over these parts, shows that such replacement costs substantially slow growth and reduce shade tolerance. These results demonstrate the strong links between allometry and growth and suggest that differences in support costs are an important cause of observed interspecific differences in height growth rate.
Membrane Insertion, Glycosylation, and Oligomerization of Inositol Trisphosphate Receptors in a Cell-free Translation System

In order to study the membrane topology, processing, and oligomerization of inositol trisphosphate receptor (IP3R) isoforms, we have utilized RNA templates encoding putative transmembrane domains to program a cell-free translation system of rabbit reticulocyte lysates supplemented with canine pancreas microsomes. In the absence of microsomes, translation of the RNA templates encoding all the putative transmembrane domains present in the C-terminal segment of the type I (1TM) and type III (3TM) IP3R isoforms resulted in a 62- and 59-kDa polypeptide, respectively. In both cases, an additional band approximately 3 kDa larger was observed upon the addition of microsomes. Both bands in the translation doublet were integrated into microsomal membranes and were full-length translation products, as shown by sedimentation through a sucrose cushion and immunoprecipitation with C-terminal isoform-specific antibodies. With both isoforms, N-glycopeptidase F digestion indicates that the upper band in the doublet corresponds to a glycosylated translation product. A 17-kDa protected fragment was observed after proteinase-K digestion of 1TM translated in the presence of microsomes. The pattern and size of protected fragments was consistent with the current six-transmembrane domain model of IP3R topology. Cotranslation of both 1TM and 3TM RNA templates in the presence of microsomes followed by immunoprecipitation with isoform specific antibodies revealed coimmunoprecipitation of translation products. This was not observed when the isoforms were translated separately and then mixed, suggesting that heteroligomerization occurs cotranslationally. A construct encoding only the first putative transmembrane domain of the type I isoform was found to be sufficient for integration into membranes but was unable to oligomerize with either 1TM or 3TM. Cotranslation experiments using additional constructs indicate that the major structural determinant for homoligomerization lies between putative transmembrane domain 5 and the C terminus. A second oligomerization domain involved in stabilization of heteroligomers is present within the first four transmembrane domains.
Academic-clinician partnerships: a model for outcomes research.

SUMMARYWhile practitioners are now asked to provide evidence that supports the services we deliver, there is little empirical evidence concerning occupational therapy interventions. Research by clinicians is limited, often due to a lack of time, institutional support and research skills. Establishing collaborative research relationships between faculty, clinicians, and graduate students has been suggested as a means of addressing these barriers. Implementation of a model teaming students with clinicians to conduct outcomes studies is described. The model will be illustrated using a case example of a collaborative research project evaluating the efficacy of a home management skills program for individuals with chronic mental illness. The benefits and challenges of the collaborative process will be described.
Chemical facilitation of a naturally occurring host shift by Papilio machaon butterflies (Papilionidae)

Host shifts by herbivorous insects have contributed substantially to current patterns of association between insects and plants. Despite their evolutionary and agricultural interest, however, the plant traits that predispose insects to colonize some plants instead of others are poorly understood. To examine whether ancestral and novel hosts share similar chemical oviposition stimulants that would facilitate a host shift, we investigated a well-substantiated host shift within the Papilio machaon group of swallowtail butterflies. Papilio machaon aliaska uses three plant species as host plants. Cnidium cnidiifolium belongs to the family Apiaceae, the ancestral host-plant family of the P. machaon group. Artemisia arctica and Petasites frigidus, by contrast, belong to the family Asteraceae and were colonized relatively recently by this group of butterflies. Papilio machaon oregonius, a close relative of P. m. aliaska, feeds and oviposits exclusively on Artemisia dracunculus, also in the Asteraceae. We made polar and nonpolar extracts of all four host plants, conducted bioassays with P. m. aliaska and P. m. oregonius females to test for oviposition stimulants, and found that the polar extracts were the most active. Using high-performance liquid chromatography, we separated the polar extracts into three fractions and again conducted bioassays with P. m. aliaska and P. m. oregonius females. The fraction containing hydroxycinnamic acid (HCA) derivatives was the only active fraction for all plant species. We further separated the HCA fraction and found two sub-fractions that were active in all of the host-plant species. Co-chromatography indicated that several major constituents of the active fractions are shared between ancestral and novel hosts. In a secondary series of experiments, we investigated chemical fractions of a non-host plant, Artemisia frigida, and identified fractions of the A. frigida extract that contained oviposition deterrents and a fraction that contained oviposition stimulants for P. m. aliaska females. We conclude that the similarity of stimulant profiles in ancestral and novel host plants is consistent with the hypothesis that plant chemistry has played a role in the establishment of this host shift.
Adolescent condom use and perceptions of risk for sexually transmitted diseases: a prospective study.

Background: The authors’ previous research has shown that in cross-sectional analysis partner-specific perceptions of risk for gonorrhea and chlamydial and HIV infection correlated with partner-specific intentions to use condoms. Goal: The goal was to determine whether partner-specific measures of perception of risk for STDs (PRSTD) predict partner-specific condom use 6 months later among high-risk and low-risk youth. Study Design: Youths aged 14 to 19 years were recruited from an STD clinic (n=236) and an HMO teen clinic (n=306) and were interviewed at baseline and at 6 months about PRSTD attitudes about condoms self-efficacy normative expectations and condom use. Results: PRSTD with a main sex partner was an independent predictor of condom use with a main sex partner in the STD clinic cohort (odds ratio=2.5; 95% CI=1.1– 6.2). There was no association between PRSTD with a casual sex partner and condom use in this cohort or between PRSTD for main or casual sex partners and condom use in the HMO teen clinic cohort. Conclusion: Interventions that target high-risk adolescents should focus on PRSTD with a main sex partner. (author’s)
Covalent immobilization of glucose oxidase on conducting ultrananocrystalline diamond thin films

We demonstrate in this report the covalent immobilization of redox enzymes onto electrically conductive ultrananocrystalline diamond (UNCD) thin films. Glucose oxidase was attached to the UNCD surface via the tethered aminophenyl functional groups which were previously grafted to UNCD surface by electrochemical reduction of aryl diazonium salt. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) observations confirmed the surface functionalization. The tethered glucose oxidase maintains its biocatalytic activity, and the electrical communication between the enzyme active sites and the UNCD surface was established using molecular oxygen as the electron mediator. Our results suggest that conductive diamond thin films, owing to their excellent mechanical, electrical and electrochemical properties, could serve as a robust platform for a new class of bioinorganic interfaces and electrochemical biosensors.
Spatially and temporally resolved detection of analytical signals in graphite furnace atomic absorption spectrometry

Abstract Spatial non-uniformities in analyte, atomizer gas phase temperature and radiant intensity distributions characteristic for graphite furnace atomic absorption spectrometry are briefly summarized and their effect on the analyte detection is analysed. It is shown that conventional detection of analyte based on the use of photomultiplier tubes provides excellent temporal resolution, sufficient wavelength isolation but totally ignores the spatial aspects of the interaction of the probing radiation beam with the analyte in the atomizer. A new, spatially resolved, method of analyte detection based on the use of a solid state detector located along the monochromator slit is presented. The approach is illustrated by the temporally and spatially resolved detection of Cd atomization and NaCl vaporization. It is shown that severe non-uniformities in atomic and/or background absorbance may be a potential source of analytical error. Advantages of spatially resolved detection as compared with conventional detection are discussed.
Selfish operons and speciation by gene transfer

Bacterial genes providing for single metabolic functions are found in operons, possibly because this organization allows efficient horizontal transfer among organisms. Transferred genes can confer novel metabolic phenotypes on their new hosts and allow rapid, effective exploitation of new environmental niches. Moreover, the mobility of selfish operons may facilitate bacterial speciation.
Display of solid-state materials using bipolar electrochemistry.

We report the formation and characterization of one-dimensional chemical composition gradients of CdS on Au surfaces using bipolar electrodeposition. When an external electric field is applied across an electrically floating Au electrode immersed in a bipolar electrochemical cell, a position-dependent interfacial potential difference is generated along the length of the Au. This potential gradient can be used to induce variations of chemical composition within thin films electrodeposited onto the Au bipolar electrode (BPE). Thin films formed by bipolar electrodeposition represent continuous one-dimensional solid-state material libraries and were screened using resonance Raman microscopy and Auger electron spectroscopy. As predicted from simple thermodynamic considerations, we observed three distinct deposition zones scanning from the cathodic pole to the midpoint of the BPE: (i) CdS+Cd, (ii) stoichiometric CdS, and (iii) elemental S. Bipolar electrodeposition can be used to generate material libraries rap...
Single word comprehension in aphasia: Influence of array size, picture relatedness and situational context

Abstract The influence of three variables on single word comprehension in 11 aphasic subjects was assessed using a picture pointing task. The variables were: the number of pictures displayed, the relationship among the pictures and the presence of a situational context. The results indicated that, when the pictures were unrelated, increasing the number of pictures did not affect accuracy until eight pictures were present. When the pictures were related based on a common situational theme but still displayed in a standard format, increasing their number impaired performance when six or eight pictures were present. Introducing a situational context impaired performance beginning with four pictures. Most of the scores on the experimental measures correlated significantly with scores from the word discrimination subtest of the Boston Diagnostic Aphasia Examination but not from the recognizing common words subtest of the Minnesota Test for Differential Diagnosis of Aphasia or the Token Test. Clinical and theor...
Nuclear magnetic resonance studies of point defects in BaF2 crystals

Abstract The spin-lattice relaxation time T1 of 19F in BaF2 crystals has been measured from 300° to 1150°K.
Cementitious-matrix composites from SiCl4-plasma-activated polypropylene fibres

Polypropylene (PP) fibres (fibrillated PP) obtained by inducing splits in PP films were treated under radio frequency (RF) (30 kHz) SiCl4-plasma conditions in a stainless steel, parallel plate, capacitively coupled reactor. Analytical investigations carried out on the pale yellow-coloured fibre demonstrated the presence of OH groups and Si atoms on the PP surfaces, resulting in improved wettability and decreased contact angle values. Surface morphologies estimated using atomic-force microscopy indicated the presence of a very rough surface structure for the plasma-treated substrates in comparison with the unmodified samples. Comparative test data from PP fibre-reinforced concrete and SiCl4-cold plasma-treated PP fibre reinforced concrete showed improved mechanical characteristics (flexural strength, flexural toughness, and toughness indices) for all of the plasma-treated fibre-based composites.
Developmental changes in the secondary xylem ofAcer rubrum induced by gibberellic acid, various auxins and 2,3,5-tri-iodobenzoic acid

The effect of GA on the development of the secondary xylem ofAcer rubrum was studied. GA was applied to seedlings (1) separately, (2) simultaneously with TIBA, and (3) simultaneously with TIBA and an auxin. GA alone is without effect on the development of the secondary xylem. In seedlings treated with TIBA-GA or TIBA-GA-auxin, the differentiation of the xylem elements is in general similar to that of seedlings treated with TIBA or TIBA-auxin respectively. GA however, does stimulate cambial activity in a localized region of the stem if the endogenous rate of cambial division is low.
Closing the Digital Divide in Sub-Saharan Africa: meeting the challenges of the information age

Aims to suggest approaches that can be applied to close the digital divide between Sub-Saharan Africa (SSA) and the rest of the world, including the provision of information and communication techn...
Dynamical Mechanisms Underlying Contrast Gain Control in Single Neurons

Recent neurophysiological experiments have revealed that the linear and nonlinear kernels of the transfer function in sensory neurons are not static. Rather, they are adaptive to the contrast or the variance of time-varying input stimuli, exhibiting a contrast gain control phenomenon. We investigated the underlying biophysical causes of this phenomenon by simulating and analyzing the leaky integrate-and-fire and the Hodgkin-Huxley neuronal models. Our findings indicate that contrast gain control may result from the synergistic cooperation of the nonlinear dynamics of spike generation and the statistical properties of the stimuli. The resulting statistics-dependent stimulus threshold is shown to be a key factor underlying the adaptation of frequency tuning and amplitude gain of a neuron's transfer function in different stimulus environments.
Marking of host fruit by male Rhagoletis boycei Cresson flies (Diptera: Tephritidae) and its effect on egg-laying

MaleRhagoletis boycei flies (Cresson) have been shown previously to guard egg-laying punctures on host walnut (Juglans major) fruit. During their tenure,R. boycei males were observed to dip the posterior portion of their abdomen repeatedly toward the fruit surface. Closeup video analysis revealed that, during this dipping behavior, a clear viscous substance emanating from the cercus was deposited directly on the fruit. Laboratory assays indicated that the rate of abdomen-dipping was significantly higher on fruit bearing simulated egg-laying punctures than on control fruit and significantly higher in the area of the puncture than elsewhere on the fruit. In a final experiment, the occurrence of abdomen-dipping in the vicinity of a puncture was manipulated independently on separate punctures on the same fruit. On such fruit and in the absence of males, previously mated, reproductively mature females attempted oviposition significantly more often in or near a puncture exposed to males than in or near an unexposed control puncture. Possible functions of the putative male-marking behavior from the perspectives of both male and female are discussed.
High breast cancer-related mortality in Armenia: Examining the breast cancer knowledge gap

report, breast cancer accounts for 31.0% of cancers and 20.3% of cancer-related deaths among women in Armenia. Its age standardized mortality rate of 24.3 per 100,000 is currently the seventh highest globally 1 . Given the improved prognoses and treatment options from early detection, understanding barriers to care within Armenia is critical to addressing this growing clinical and public health issue. This study was conducted to access knowledge about breast cancer risk factors, signs and symptoms, and early diagnosis among women in Armenia to examine possible gaps in knowledge contributing to the high breast cancer mortality rate in Armenia. Responses to the yes/no/I don’t know questions regarding breast cancer knowledge were scored based on available evidence in medical literature. “I don’t know” responses were scored as incorrect for the purposes of this study. A breakdown of average scores and their corresponding standard deviations are presented in Figure 3. With an average score of 58.5%, knowledge concerning breast cancer risk factors showed significant difference with a higher education level (p -value <0.0001). Age showed some difference, with the 30-49 and 50-64 year old demographics having the highest knowledge level (p-value 0.0336). Those employed in professional capacities tended to have higher risk factor knowledge (p-value 0.0028). Results by question are shown in Figure 4.
Developing a 3D simulated bio-terror crises communication training module

The anthrax attacks of 2001 brought professional and public attention to the significance of successful crisis communication in the context of bioterrorism. The project discussed in this paper is an initiative taken to respond to the calls for more effective bio-terror crises communication training. The goal of this project is to address various challenges in bio-terror crises communication by developing an innovative crisis communication training module for public relations students. This goal is achieved by attending to two main factors: (a) keen awareness of important theories in crises communication response, and (b) "hands-on" training in real-time bio-terror communication handling techniques. This paper introduces the process taken to develop 3D simulated crisis communication training material and presents future plans to assess its effectiveness.
An Experimental Method for Testing Numerical Stability in Initial-Value Problems

Abstract The numerical stability of evolutionary calculations can be tested experimentally by running two calculations in parallel, starting from initial conditions that are very similar, and monitoring the differences between the systems. An integration of an n -body system with gravitational interactions provides an example that is useful for illustrative purposes. Some features of the method are described, followed by a discussion of some considerations in its application.
Mental health, stress, and poor health behaviors in two community samples.

Abstract Background . The relationships of obesity, smoking, drinking, and lack of exercise to mental health and stress were evaluated in separate community samples of men and women. Results . Among men, the only significant positive relationship was between history of depression and smoking. Among women, four psychosocial factors were associated with smoking: history of depression, increased marital conflict, greater number of undesirable life events, and full-time employment. Depression and marital conflict were also associated with higher drinking levels, and full-time employment was associated with lack of exercise. History of emotional disorders was not found to exacerbate the effects of stress on poor health behaviors. However, some combinations of stress were detrimental. Among men, the joint effect of high job demands and low decision latitude was significantly associated with a greater likelihood of smoking. Among women, the interaction of full-time employment and greater marital conflict was associated with increased alcohol use. Conclusion . These results emphasize the importance of considering gender-specific risk factors in the design of intervention programs.
A non-sequential method for constructing trees and hierarchical classifications.

A procedure is presented that forms an unrooted tree-like structure from a matrix of pairwise differences. The tree is not formed a portion at a time, as methods now in use generally do, but is formed en toto without intervening estimates of branch lengths. The method is based on a relaxed additivity (four-point metric) constraint. From the tree, a classification may be formed.
Word Problems: Reflections on Embedding Quantitative Literacy in a Calculus Course

Abstract Even though Quantitative Literacy (QL) programs are currently being developed and implemented in severalcolleges and universities, most schools still depend on traditional mathematics courses to reach theirquantitative literacy goals. This note is a case study of how a traditional mathematics course sequenceintended for students majoring in social and life sciences may be modified and adapted to at least partiallyfulfill the need in the absence of a stand-alone QL program. In particular, we focus on a freshman-levelmathematics course sequence that serves various client departments. This sequence covers the traditionalcontent of a first-year calculus sequence along with a clear and intentional emphasis on word problems. Thekinds of word problems used are not necessarily limited to those that require or make substantial use of acalculus background. However in this perspective we propose that various levels of word problems may beused successfully to satisfy QL goals. Descriptions of QL mainly focus on going from the mathematical dataand presentations to an understanding of the real world. In this note we surmise that word problems go in theopposite direction and, in some sense, close the loop in QL.
On the difference between using linear and non‐linear models in bracketing procedures in isotope dilution mass spectrometry

We examine the difference between a linear and a non-linear model for the calculation of analyte concentration by interpolation between standards in isotope dilution/mass spectrometry. Equations are developed for calculating this difference for various increments of the bracketing intensity ratios and for various compositions of the sample; graphs are also presented to depict this difference for these various conditions. As an illustration, the result for a series of measurements on urea are presented and discussed.
Relation between electromagnetically induced absorption resonances and nonlinear magneto-optics in Λ systems

Recent work on {lambda} resonances in alkali-metal vapors (E. Mikhailov, I. Novikova, Yu. V. Rostovtsev, and G. R. Welch, e-print quant-ph/0309171, and references therein) investigated a type of electromagnetically induced absorption resonance that occurs in three-level systems under specific conditions normally associated with electromagnetically induced transparency. In this note, we show that these resonances have a direct analog in nonlinear magneto-optics, and support this conclusion with a calculation for a J=1{yields}J{sup '}=0 system interacting with a single, nearly circularly polarized light field in the presence of a weak longitudinal magnetic field.
Makisterone C: A 29-carbon ecdysteroid from developing embryos of the cotton stainer bug, Dysdercus fasciatus

An ecdysteroid RIA was used to determine the ecdysteroid titer in developing embryos of Dysdercus fasciatus and revealed that peak titer occurred approximately 120 h post-oviposition. Analysis of neutral sterols at this time indicated sitosterol to be the predominant neutral sterol with lesser amounts of campesterol. Embryonic sterols were highly reflective of the sterols found in the cotton seed diet upon which previous generations of the bugs had fed. Analysis of the embryonic extract for ecdysteroids indicated the presence of both makisterone A and the 29-carbon ecdysteroid makisterone C. Isolation of these compounds was accomplished by reversed-phase and silica HPLC in conjunction with RIA, and the identification of both compounds was confirmed by mass spectrometry. No ecdysone or 20-hydroxyecdysone was detected in the embryonic sample.
Ionizing radiation in glioblastoma initiating cells.

Glioblastoma is the most common primary malignant brain tumor in adults with a median survival of 12-15 months with treatment consisting of surgical resection followed by ionizing radiation (IR) and chemotherapy. Even aggressive treatment is often palliative due to near universal recurrence. Therapeutic resistance has been linked to a subpopulation of GBM cells with stem-cell like properties termed glioblastoma initiating cells (GICs). Recent efforts have focused on elucidating resistance mechanisms activated in GICs in response to IR. Among these, GICs preferentially activate the DNA damage response (DDR) to result in a faster rate of double-strand break (DSB) repair induced by IR as compared to the bulk tumor cells. IR also activates NOTCH and the hepatic growth factor (HGF) receptor, c-MET, signaling cascades that play critical roles in promoting proliferation, invasion, and resistance to apoptosis. These pathways are preferentially activated in GICs and represent targets for pharmacologic intervention. While IR provides the benefit of improved survival, it paradoxically promotes selection of more malignant cellular phenotypes of glioblastoma. As reviewed here, finding effective combinations of radiation and molecular inhibitors to target GICs and non-GICs is essential for the development of more effective therapies.
A Model for the Electroreduction of Molecular Oxygen

The kinetics of the oxygen reduction reaction (ORR) was studied by decomposing the polarization curves obtained using a polycrystalline platinum rotating disk electrode in an aqueous sulfuric acid electrolyte. The ORR model that is presented is novel in its expression of the pre-exponential factor in the traditional Butler-Volmer equation. It is postulated that this term can be described as an intrinsic kinetic frequency factor multiplied by a series of probability functions that describe the kinetic behavior based on spatial, energetic, and electron-transfer effects. Literature values are taken for the oxygen-binding energy to calculate the adsorption equilibrium behavior and both the activation energy and electron tunneling are used to quantify the kinetic probability functions. The frequency factors have been calculated as 2.0 s -1 for the four-electron reduction and 1.3 x 10 2 s -1 for the two-electron reduction. The model appears to simulate important features of the ORR, including the magnitude of the observed current and the activation overpotential, though slight deviations in the potential persist. Results of the model are used to discuss the potential to describe tailor-made catalysts for the ORR.
Life-history variation and adaptation in the historically mobile plant Arabidopsis thaliana (Brassicaceae) in North America

We used field-collected seeds of Arabidopsis thaliana (Brassicaceae) to simulate a colonization event of plants from diverse locations into a common environment to compare regionally "local" and "foreign" populations of this historically mobile species. Life history varied among regional groups, but most variation was found among populations within regions. While we found significant differences among populations and regional groups for important life-history characters, we did not find significant differences in performance of plants from different populations or regional groups. Rather, we found evidence that differences in life history contributed to the ability of plants from foreign regions to perform comparably to local Kentucky plants. Had plants from different regions not differed in the timing and size of reproduction, we would have seen that Kentucky (local) plants had higher total fitness via greater reproductive success of individuals that survived to reproduce and that Michigan plants would have had the lowest fitness. The populations are comparably adapted to the environment in Kentucky but through different combinations of life-history characters. Therefore, the life-history variation in this mobile species appears to contribute not to fitness differences among populations but rather to success in colonizing new locations.
Immunologic alterations by environmental chemicals: relevance of studying mechanisms versus effects.

AbstractA number of environmental chemicals are known to modify the immune responses via a number of different mechanisms. Immunologic systems are vital to the well-being of individuals and a number of toxic effects are likely to be produced by chemical alteration of its processes. A variety of tests have been suggested for screening existing or new chemicals with regards to their potential to modify the immune responses. It is well recognized that immune responses are highly temporal (time-related) and the outcome of a test is likely to he influenced by the specific protocol employed and other factors that may involve the test organism. Although standardization of tests will probably reduce some of this variability, test standardization is not expected to provide more valuable information than can be already predicted by the routine evaluation of chronic toxicity and clinical parameters. The need for studying the mechanisms involved in the modification of immunologic processes by exogenous and even endog...
Picosecond CARS measurements of nitrogen rotational/translational and vibrational temperature in a nonequilibrium Mach 5 flow

Picosecond Unstable-resonator Spatially Enhanced Detection Coherent Anti-Stokes Raman Scattering (USED-CARS) is used for the measurement of nitrogen Q-branch (ΔJ = 0) spectra in the subsonic plenum and supersonic flow of a highly nonequilibrium Mach 5 wind tunnel. Spectra are processed to infer rotational/translational (T rot) and first-level vibrational (T vib) temperatures in the 200–370 torr plenum simultaneously. Operation of the nominally high reduced electric field (E/n peak ~ 500 Td), nsec pulsed discharge alone results in fairly significant vibrational loading, T vib ~ 720 K/T rot ~ 380 K; addition of an orthogonal low E/n (~10 Td) DC sustainer discharge produces substantial vibrational loading, T vib ~ 2,000 K/T rot ~ 450 K. Effects of injection of CO2, NO, and H2 downstream of the pulser–sustainer discharge are examined, which result in vibrational relaxation accompanied by simultaneous gas heating, T vib ~ 800–1,000 K/T rot ~ 600 K. CARSk measurements within very low-density flows in the Mach 5 expansion nozzle are also performed, with T vib measured in both the supersonic free-stream and downstream of a bow shock created by a 5-mm-diameter cylindrical test object in the Mach 5 flow. Measurements within 300 μm of the cylinder leading edge show that for pure N2, or N2 with 0.25 torr CO2 injection, no vibrational relaxation is observed behind the bow shock.