cssi/SciSciGPT-SciSciNet huggingface dataset:
A RAPID PROCEDURE FOR CATALASE DETERMINATION IN BLOOD AND TISSUE SAMPLES WITH THE VAN SLYKE MANOMETRIC APPARATUS.

A precise and rapid gasometric procedure is described for catalase determination in blood and tissue samples. The enzyme activity assay is performed with the Van Slyke manometric apparatus. In the developed technicw, a 45-sec. reaction period is used, and a large liquid-gas interphase is provided with the purpose of preventing the oxygen diffusion from becoming a rate-limiting factor. Under the devised methodological conditions, the rate of oxygen evolution closely follows a parabolic curve which permits the calculation of the initial activity velocity of the enzyme. The oxygen evolvement is directly proportional to the quantity of catalase present in the analyzed sample. Less than 4 min. are required for each catalase measurement.
An essential yeast gene encoding a TTAGGG repeat-binding protein

A yeast gene encoding a DNA-binding protein that recognizes the telomeric repeat sequence TTAGGG found in multicellular eukaryotes was identified by screening a lambda gt11 expression library with a radiolabeled TTAGGG multimer. This gene, which we refer to as TBF1 (TTAGGG repeat-binding factor 1), encodes a polypeptide with a predicted molecular mass of 63 kDa. The TBF1 protein, produced in vitro by transcription and translation of the cloned gene, binds to (TTAGGG)n probes and to a yeast telomeric junction sequence that contains two copies of the sequence TTAGGG separated by 5 bp. TBF1 appears to be identical to a previously described yeast TTAGGG-repeat binding activity called TBF alpha. TBF1 produced in vitro yields protein-DNA complexes with (TTAGGG)n probes that have mobilities on native polyacrylamide gels identical to those produced by partially purified TBF alpha from yeast cells. Furthermore, when extracts are prepared from a strain containing a TBF1 gene with an antigen tag, we find that the antigen copurifies with the predominant (TTAGGG)n-binding activity in the extracts. The DNA sequence of TBF1 was determined. The predicted protein sequence suggests that TBF1 may contain a nucleotide-binding domain, but no significant similarities to any other known proteins were identified, nor was an obvious DNA-binding motif apparent. Diploid cells heterozygous for a tbf1::URA3 insertion mutation are viable but upon sporulation give rise to tetrads with only two viable spores, both of which are Ura-, indicating that the TBF1 gene is essential for growth. Possible functions of TBF1 (TFB alpha) are discussed in light of these new results.
A network architecture for precision formation flying using the IEEE 802.11 MAC protocol

Precision formation flying (PFF) missions involve the tracking and maintenance of spacecraft in a desired geometric configuration. Autonomous control of the distributed spacecraft requires inter-spacecraft communications with guaranteed performance. We present a network architecture that supports PFF control across the various phases of mission operations, ranging from initial random deployment to precision formation. The architecture incorporates the IEEE 802.11 MAC protocol and utilizes both its distributed control function (DCF) and point coordination function (PCF) modes as appropriate to the PFF operational phase. A proactive routing protocol provides timely topology status. A new application layer protocol is incorporated which provides a simple interface between the PFF control application and the underlying communications network
Intravenous injection of [1-14C]arachidonate to examine regional brain lipid metabolism in unanesthetized rats.

We examined the metabolic disposition and brain distribution of an unsaturated fatty acid, [1-14C]arachidonate, between 5 and 240 min following its intravenous bolus injection in unanesthetized adult rats. Injected [1-14C]arachidonate was cleared rapidly from plasma, with less than 10% remaining by 2 min. Total brain radioactivity, 0.2% of the injected dose, was near maximal by 5 min, reached a peak by 15 min, then slowly declined. Radioactivity in brain lipids constituted greater than 82% of the total brain radioactivity at all times. Radioactivity in aqueous-soluble metabolites was greatest at 5 min (13% of total) and declined to 5% by 240 min. Protein pellet-associated radioactivity gradually rose to a peak of 7% by 120 min. Within the lipid fraction, more than 92% of radioactivity was in glycerolipids, with greater than 81% in phospholipids. Radioactivity in inositol phosphoglyceride was maximal at 5 min (47% of phospholipid radioactivity); and declined to 34% by 20 min, whereas radioactivity in choline phosphoglyceride peaked at 15 min (41% of phospholipid radioactivity) and was constant thereafter. In contrast, radioactivity in ethanolamine phosphoglycerides increased from 7 to 17% during the course of the experiment. Quantitative autoradiography of brain sections indicated incorporation of [1-14C]arachidonate into gray-matter regions was 1.5- to threefold that into white-matter regions. The data were analyzed in terms of a model for brain fatty acid uptake from plasma. Estimates of unidirectional transfer constants, k, for [1-14]arachidonate from plasma to brain regions with an intact blood-brain barrier ranged from 0.0005 to 0.0015 ml.sec-1.g-1 and were correlated with those for [9,10-3H]palmitate. The results indicate that brain phospholipid metabolism in awake animals can be examined regionally and quantitatively using intravenous injection of [1-14C]-arachidonate combined with quantitative autoradiography and biochemical analysis.
A checklist for evaluating ergonomic risk factors associated with upper extremity cumulative trauma disorders.

A two-page checklist for determining the presence of ergonomic risk factors associated with the development of upper extremity cumulative trauma disorders (e.g., repetitiveness, local mechanical contact stresses, forceful manual exertions, awkward postures, and hand tool usage) was developed and evaluated as part of a joint labour-management ergonomics intervention programme. This checklist was used by plant personnel at four work sites to assess the presence of upper extremity risk factors in 335 manufacturing and warehouse jobs. In addition, results generated by the checklist were compared to the results of ergonomic analyses performed by persons with advanced training (Masters degree) in occupational ergonomics for a subset of 51 jobs. Most of the jobs included in the survey were found to have significant exposures to upper extremity risk factors. Awkward work postures were common, with 90% of the jobs requiring wrist deviations outside the neutral range-of-motion. The jobs were also highly repetitive and frequently required workers to exert high hand forces. Results generated by the checklist were generally in agreement with results generated by the ergonomic analysts; however, the checklist was found to be more sensitive in identifying the presence of risk factors. The checklist was found to be an effective rapid-screening instrument for identifying jobs that expose workers to potentially harmful ergonomic stresses. However, the checklist methodology did not include sufficient documentation of work methods to identify specific job attributes associated with these exposures.
Carbon isotopes in exhaled breath track metabolic substrates in brown bears (Ursus arctos)

Abstract Dietary carbon is oxidized and exhaled as CO2, thus δ13Cbreath values can provide information on diet and substrate use for energy. However, physiological phenomena such as fat deposition and fasting can alter values of δ13Cbreath such that interpretation of source contributions may be unclear. Consequently, before application to free-ranging animals, inferences about feeding and nutritional states based on δ13Cbreath should be validated with controlled experiments using captive individuals. Here, we report δ13Cbreath values for 4 captive brown bears (Ursus arctos) under different conditions: the bears were 1st given a diet containing carbohydrate, lipid, and protein; they were then switched to a carbohydrate-free diet consisting of salmon and fish oil; and finally they were placed on a fast leading to winter hibernation. Following the switch to the carbohydrate-free diet, values of δ13Cbreath and δ13Cplasma suggested that although oxidation included a substantial portion of dietary proteins, die...
Excitation of deuterium double-quantum transitions in liquids

Abstract Multiple-quantum transitions of nuclei with a magnetic quantum number larger than one half can be excited with non-selective rf pulses provided there is a resolved heteronuclear coupling to another spin species. This effect is illustrated by detecting deuterium double-quantum spectra in liquids.
Effects of suppressing plasma FSH on ovarian follicular dominance in cattle

The importance of FSH during development of the dominant follicle of the first wave of follicular growth in cattle was assessed by injecting heifers twice daily with 20 ml saline (n = 6) or 20 ml charcoal-extracted bovine follicular fluid (bFF; n = 10), containing inhibin, on days 6 and 7 of the oestrous cycle. All animals received a luteolytic dose of PGF2 alpha on day 8. The interval to oestrus after PGF2 alpha in controls was 2.6 +/- 0.2 days. Five of ten bFF-treated heifers exhibited oestrus at the same time as controls (2.7 +/- 0.1 days), whereas time to oestrus in the remaining five bFF-treated heifers was significantly longer (6.8 +/- 0.6 days; P < 0.05). Treatment with bFF suppressed plasma FSH during the 48 h injection period (P < 0.05). Concentrations of FSH were not different in bFF-treated animals that did not display delayed oestrus compared with those in animals that exhibited delayed oestrus. In controls, the dominant follicle of the first wave continued growing during treatment and ovulated after injection of PGF2 alpha. In all ten bFF-treated animals, growth of the dominant follicle of the first wave was arrested during the treatment period. In bFF-treated animals that did not exhibit delayed oestrus, the dominant follicle resumed growth after luteolysis and ovulated. In bFF-treated animals that displayed delayed oestrus, the dominant follicle regressed after luteolysis and the ovulatory follicle was selected from a newly recruited (second) wave of follicular growth.(ABSTRACT TRUNCATED AT 250 WORDS)
Electrochemical etching of fast neutron induced recoil tracks in cellulose triacetate

Abstract Optimum parameters for electrochemical etching (ECE) of fast-neutron irradiated Kodak cellulose triacetate have been established. When etching in KOH solution at 25°C for 4 h, the optimum frequency is 3.4kHz, the optimum voltage gradient is 13kV cm−1, and the optimum concentration is 8 N. The clearly visible etched tracks have a mean diameter of 180μm under these conditions. The optimum frequency and voltage gradient were obtained from differential leakage-current measurements made between unirradiated and fast-neutron irradiated foils in which the maximum differential leakage-current was sought. The lower limit of detectability is 170mrad of fast neutrons. This is an order of magnitude too insensitive for practical personnel dosimetry. One of the limiting factors is a background track density of ∼ 20 tracks cm−2. The threshold energy for track registration in cellulose triacetate has yet to be established experimentally but is expected to be less than that for polycarbonate.
Sodium bicarbonate cotransporter polymorphisms are associated with baseline and 10-year follow-up blood pressures.

The NaHCO 3 cotransporter gene ( SLC4A5 ) on chromosome 2 encodes a protein that transports sodium and bicarbonate across the cell membrane and regulates cellular pH. The National Heart, Lung, and Blood Institute Family Blood Pressure Program found linkage of blood pressure–related traits to the chromosomal region containing SLC4A5 and phenotype associations with single nucleotide polymorphisms (SNPs) in this gene. However, the results were inconsistent over various phenotypes and SNPs. Nevertheless, the evidence was strong enough to propose this gene as a blood pressure–related gene. To extend these findings, SLC4A5 SNPs were genotyped in an independent set of 96 Utah pedigrees of 1040 adult subjects at baseline, 760 of whom were followed longitudinally for 10 years. After adjusting for age, gender, body mass index, and polygenic correlations within pedigrees, SNP hcv1137534 was significantly associated with both systolic blood pressure and diastolic blood pressure (DBP) at baseline (unadjusted P =0.009 and P =0.043; respectively) and at 10-year follow-up ( P =0.008 and P =0.007; respectively). In secondary tests of association of baseline-stressed blood pressure, hcv1137534 was borderline or significantly associated with DBP change during an isometric handgrip test ( P =0.054), DBP change from supine to standing ( P =0.020), and DBP change after a 50° tilt ( P =0.034). There was no evidence for compensation of abnormal SLC4A5 sodium transport by genotype-specific differences in sodium–lithium countertransport, lithium–potassium cotransport, altered plasma sodium, chloride, or CO 2 levels. Therefore, in these Utah pedigrees, the SLC4A5 gene was significantly associated with blood pressure and persisted after 10 years of follow-up. These results additionally confirm the involvement of SLC4A5 with blood pressure control, although the mechanism is still unclear.
A thematic approach to system safety

Sandia National Laboratories (Sandia) has refined a process for developing inherently safer system designs based on methods used by Sandia to design detonation safety into nuclear weapons. The process was created when Sandia realized that standard engineering practices did not provide the level of safety assurance necessary for nuclear weapon operations, with their potential for catastrophic accidents. A systematic approach, which relies on mutually supportive design principles integrated through fundamental physical principles, was developed to ensure a predictably safe system response under a variety of operational and accident-based stresses. Robust, safe system designs result from this thematic approach to safety, minimizing the number of safety critical features. This safety assurance process has two profound benefits: the process avoids the need to understand or limit the ultimate intensity of off-normal environments and it avoids the requirement to analyze and test a large array of accident environment scenarios (e.g., directional threats, sequencing of environments, time races, etc.) to demonstrate conformance to all safety requirements.
Stress echocardiography for evaluation of hemodynamics: Valvular heart disease, prosthetic valve function, and pulmonary hypertension

A broad variety of diseases can affect dynamic cardiac function and contribute to exertional symptoms. Although hemodynamic data at rest may be sufficient to guide therapy in some patients with cardiovascular disease, medical and surgical decisions may be impacted by the cardiac response to stress and the ability to associate exertional symptoms with cardiac hemodynamic response. Stress echocardiography/Doppler provides a unique noninvasive means to evaluate cardiovascular function and ehmodynamic responses during increased cardiac work. Specifically, stress echocardiographic/Doppler imaging allows assessment of the response to exercise of left and right ventricular function, transvalvular and prosthetic valve gradients, and right ventricular systolic pressure. It has substantial clinical use in the evaluation of patients with equivocal evidence of mitral stenosis, suspicion of dynamic mitral insufficiency or prosthetic valve dysfunction, aortic stenosis and impaired left ventricular systolic function, diseases associated with pulmonary hypertension or cor pulmonale, and among patients with dyspnea of unknown origin. The dynamic nature of cardiovascular disease and the broad spectrum of diseases that affect cardiac function make exercise echocardiography/Doppler an ideal tool ideal for the noninvasive assessment of patients with symptoms of exertional dyspnea.
Evidence on equity private placements and going-out-of-business information release

Abstract In our study, shareholder wealth gains around announcements of equity private placements primarily came from firms which subsequently went out of business. Investors’ positive response was consistent with an expected greater survival likelihood for more troubled firms, but with no such revisions for stronger companies. Inconsistent with their apparent beliefs, going-out-of-business companies had statistically significant and material negative abnormal returns that averaged 17.5% from prior to and until 150 days after the announcement period. Still-in-business companies had insignificant abnormal returns over either the announcement or post announcement period. The evidence on failing businesses is consistent with a semi-strong form of efficient markets hypothesis violation.
Interureteric ridge edema: incidence and etiology

Background Interureteric ridge edema may be seen at intravenous urography (IVU) and is related to acute lower ureteral obstruction, trauma, or calculi. The purpose of this study was to explore the relationship between interureteric ridge edema and acute distal ureteral obstruction caused by ureteral calculi.
Investigation of Factors Influencing Release of Solid Drug Dispersed in Inert Matrices IV: Some Studies Involving the Polyvinyl Chloride Matrix

Abstract The mechanism of drug release from tablets made from mixtures of drug and polyvinyl chloride particles was investigated. Experimental data were evaluated by me:ans of the Higuchi relationship for the process. The S-shaped nature of the amount released versus (time) 1/2 plots was studied, and it appears that this behavior was the result of the relatively slow release of air from the tablets. Matrix tortuosities ranging from about 1.5 to 3.0 were found for these polyvinyl chloride matrices.
Influences of Obesity on Job Demands and Worker Capacity

Evidence suggests that the growing prevalence of obesity in the workforce has resulted in an increase in the incidence and cost of musculoskeletal injuries. Obesity can modify job demands and affect worker capacity in terms of anthropometry and occupational biomechanics, which may place workers at greater risk of injury. This paper presents a review of studies quantifying the work-relevant impacts of obesity, specifically related to work task demands, capacities, and their potential imbalance. The increased body fat that accompanies obesity leads to larger anthropometric dimensions and inertial parameters, particularly in the trunk and thigh areas. Consequently, individuals who are obese adjust their work postures and motions as an accommodation. These changes may affect the biomechanical demands on the joints and increase the burden on the musculoskeletal system. Independent of job demands, obesity-related differences also occur with respect to strength, fatigue, and task performance. Directions for future research are provided, focusing on the need for workplace redesign to account for changing workforce demographics.
Functionalized silicon membranes for selective bio-organism capture

Membranes with various pore size, length, morphology and density have been synthesized from diverse materials1,2,3,4,5 for size-exclusion-based separation. An example is the sterilization of intravenous lines by exclusion of bacteria and viruses using polyvinylidene fluoride membranes with 0.1-μm-diameter pores. Chemically specific filtration has recently been addressed for small molecules6,7,8,9,10. Nevertheless, specific bio-organism immobilization and detection remains a great technical challenge in many biomedical applications, such as decontamination or analysis of air and liquids such as drinking water and body fluids. To achieve this goal, materials with controlled pore diameter, length and surface chemistry are required. In this letter, we present the first functionalized silicon membranes and demonstrate their ability to selectively capture simulated bio-organisms. These extremely versatile and rigid devices open the door to a new class of materials that are able to recognize the external fingerprints of bio-organisms—such as size and outer membrane proteins—for specific capture and detection applications.
Boundary effects on helical textures in superfluid 3 He-A

The effect of a boundary on magnetically induced helical textures in superfluid3He-A is studied for the dipole-locked Ginzburg-Landau regime. With increasing magnetic field, the pitch at the wall remains constant, but its value deep in the bulk changes as suggested by Vollhardt, Lin-Liu, and Maki. No unstable surface normal modes are found, so that the instability of the semiinfinite helical texture remains a bulk phenomenon.
Ultrastructural studies of complement mediated cell death: a biological reaction model to plasma membrane injury

Complement-mediated nucleated cell death has been shown to be independent of colloid-osmotic swelling. In contrast, other factors (e.g. Ca2+ influx) are of importance in the induction of cell death. In this communication, the sequential morphological features of complement-mediated cell injury have been studied by electron microscopy and compared with biochemical data (ATP content and LDH release). It was observed that immediately after C5b-8 lesion formation, although the overall cell, morphology is well preserved, the mitochondria display an "ultracondensed" appearance. Upon addition of C9, the mitochondria remain initially condensed, but swell progressively with final formation of flocculent densities. The nuclei become progressively edematous, with concurrent disappearance of heterochromatin. The nucleoli lose their associated chromatin and display segregation of their components with formation of markedly electron-dense filamentous deposits. The nuclear envelope remains initially intact, but subsequently progressive dilatation of the associated perinuclear RER cisterna and distention of the nuclear pores associated with leakage of chromatin into the cytoplasm are seen. The larger cell organelles (including mitochondria, ER, Golgi apparatus, etc.) become clustered around the nucleus, concurrently with marked edema of the outer cytoplasm and bleb formation. The RER cisternae become dilated, whereas the Golgi complex disappears. Relatively early on the plasma membrane shows breaks in continuity. The pattern of these changes--potentially related to Ca2+ influx, ATP efflux and overall metabolic depletion--corresponds to the previously described model of cell reaction to injury, confirming the dynamic nature of the process. The morphology of cell death in this model shares some features, e.g., the nucleolar changes, with "apoptosis" (programmed cell death). However, the overall pattern appears to correspond more to "necrosis," characterized by loss of volume control and mitochondrial abnormalities.
Prenatal Rapamycin Results in Early and Late Behavioral Abnormalities in Wildtype C57Bl/6 Mice

Mammalian target of rapamycin (mTOR) signaling has been shown to be deregulated in a number of genetic, neurodevelopmental disorders including Tuberous Sclerosis Complex, Neurofibromatosis, Fragile X, and Rett syndromes. As a result, mTOR inhibitors, such as rapamycin and its analogs, offer potential therapeutic avenues for these disorders. Some of these disorders—such as Tuberous Sclerosis Complex—can be diagnosed prenatally. Thus, prenatal administration of these inhibitors could potentially prevent the development of the devastating symptoms associated with these disorders. To assess the possible detrimental effects of prenatal rapamycin treatment, we evaluated both early and late behavioral effects of a single rapamycin treatment at embryonic day 16.5 in wildtype C57Bl/6 mice. This treatment adversely impacted early developmental milestones as well as motor function in adult animals. Rapamycin also resulted in anxiety-like behaviors during both early development and adulthood but did not affect adult social behaviors. Together, these results indicate that a single, prenatal rapamycin treatment not only adversely affects early postnatal development but also results in long lasting negative effects, persisting into adulthood. These findings are of importance in considering prenatal administration of rapamycin and related drugs in the treatment of patients with neurogenetic, neurodevelopmental disorders.
Experimental evaluation of the holding power/stiffness of the self-tapping bone screws in normal and osteoporotic bone material

Abstract Objective. The goal of this study is to compare the holding power of the self-tapping bone screws in normal and osteoporotic bone materials. Background. Self-tapping screws are increasingly being used in orthopaedic surgery due to their advantages over the other bone screws. Methods. Screws were divided into five groups (six screws per group) based on the depth of insertion in the bone coupons that represented normal and osteoporotic bones. Screws were randomly inserted into the bone coupons with tips of the screws being −1 mm, 0 mm, 1 mm, 2 mm and 3 mm relative to the far cortex. Biomechanical testing was performed using an Instron 8511 in accordance with the American Society for Testing and Materials standards for bone screws. Two-factor analysis of variance (ANOVA) was used to determine if the holding power of the screws were different with respect to insertion depths and bone materials. Findings. The bone materials had a significant difference (P Interpretation. Based on the results it can be concluded that the depth of insertion of the tip of the screw for adequate fracture fixation in normal bone is 1 mm or more past the far cortex and in osteoporotic bone it is at least 2 mm past the far cortex.
Decoupling and destabilizing in spontaneously broken supersymmetry

The supersymmetric analog of the Goldberger-Treiman relation plays a critical role in the low energy effective theory of models in which supersymmetry is spontaneously broken in a hidden sector. The interactions that connect the hidden and visible sectors break a global symmetry, which implies that the low energy theory must be constructed consistently in inverse powers of the messenger scale. The Goldberger-Treiman relation determines the couplings of the Goldstino to the visible sector fields. These couplings are fixed by the soft supersymmetry breaking terms within a power counting scheme that is stable under radiative corrections. We describe the power counting of the low energy effective theory, first for a toy model of extended technicolor and then for the supersymmetric standard model. One implication of this work for supersymmetry phenomenology is the observation that Goldstino loops can destabilize the weak scale if the low energy theory is not constructed consistently. Another is that Goldstino loops induce all visible sector operators not forbidden by symmetries. The magnitudes of these operators are determined by the consistent power counting of the low energy effective theory.
Cadmium removal using Cladophora in batch, semi-batch and flow reactors.

Abstract This study presents the results of using viable algae to remove cadmium from a synthetic wastewater. In batch and semi-batch tests, a local strain of Cladophora algae removed 80–94% of the cadmium introduced. The flow experiments that followed were conducted using non-local Cladophora parriaudii . Results showed that the alga removed only 12.7(±6.4)% of the cadmium introduced into the reactor. Limited removal was the result of insufficient algal quantities and poor contact between the algae and cadmium solution.
EXACT SOLUTIONS FOR CORRELATIONS IN THE KAGOME ISING ANTIFERROMAGNET

The kagome Ising antiferromagnet is highly frustrated with its pair correlation decaying exponentially at large distance for all temperatures including absolute zero. Hence, the spin system does not support long-range orderings and is devoid of any phase transition. One proves, via local star-triangle and decoration-decimation transformations, that correlations in the kagome Ising antiferromagnet at arbitrary temperatures can be represented as linear combinations of correlations in the honeycomb Ising ferromagnet at high temperatures (disordered region). Existent knowledge of all honeycomb Ising correlations upon a select (spatially compact) 10-site cluster is thus sufficient to determine all present kagome Ising correlations upon an associated 9-site cluster. Examples of resulting exact solutions for pair and multisite correlations in the kagome Ising antiferromagnet are presented at all temperatures. Applications include joint configuration probabilities, thermodynamic response functions such as the specific heat and the initial perpendicular susceptibility, and the inelastic neutron scattering function.
Interactive effects of herbivory and sand burial on growth of a tropical dune plant, Ipomoea pes‐caprae

1. This study examined the effects of insect herbivory, sand burial, and the interactive effects of these factors, on the growth of beach morning glory, Ipomoea pes-caprae, a common tropical dune plant. Levels of herbivory and sand burial were manipulated on individual shoots, and effects on stem growth, leaf production, and production of adventitious roots and axillary branches by nodes were examined. 2. Sand burial had a significant positive effect on the production of roots, but did not affect growth in stem length or leaf production. 3. Effects of herbivory were consistently negative, and persisted for 6 weeks after the herbivore damage was incurred. Stem growth rates and leaf production decreased and the production of bare nodes (with no roots or branches) and mortality of apical meristems increased. 4. Interactive effects of herbivory and sand burial influenced both leaf production and root production. In the case of root production, the effects of herbivory in decreasing the proportion of nodes that produced roots occurred only in the presence of burial. In contrast, burial masked the negative effects of herbivory on leaf production.
Recent increase in Pacific CaCo3 dissolution: A mechanism for generating old 14C ages

Abstract Western equatorial Pacific box cores taken from water depths greater than 4 km show increased dissolution and anomalously old 14C ages in the upper 8 cm. The temporal response of the vertical distribution of sediment carbonate fraction and 14C age to a decrease in the dissolved carbonate ion concentration of the deep sea is examined with a diffusion—advection—dissolution model. The nature of this response is highly sensitive to both the magnitude of the dissolved carbonate-ion decrease and the rate of mixing of the upper few centimeters of sediment. If the sediment is initially calcareous and the increase in undersaturation is sufficient to eventually dissolve away most of the solid carbonate, the system relaxes on a very long time scale, greater than 10,000 years. The dissolution flux in such a case temporally is greater than the total sedimentation input, and chemical erosion occurs. The cumulative erosion is about 4 times greater for strong sediment mixing (D = 200 cm)2 ka−1) than for weak mixing (D = 2 cm2 ka−1). The chemical erosion causes old carbonate to be transferred into the sediment “mixed layer” as the interface moves downwards. Thus, the 14 C 12 C ratio initially decreases. When erosion decreases because the surface carbonate content is diminished, the 14C age of the sediment continues to become older in the case of weak mixing, but reverses itself and becomes younger in the presence of moderate or strong mixing. An attempt to predict the observed %CaCO3 and 14 C 12 C in west equatorial Pacific sediment suggests that beginning a few thousand years ago, the deep Pacific was 20% more undersaturated than today for about 1500 yrs. This could possibly have been caused by late Holocene growth of coral reefs following after the deglaciation.
Engineering active siRNA therapeutics.

The discovery of RNA interference (RNAi) has led to a rush to develop short interfering RNAs (siRNAs) for a variety of applications, especially for therapeutics. A particular advantage of RNAi-based therapeutics is that they utilize the existing regulatory machinery of gene expression in eukaryotic cells. For this reason, siRNAs have the potential to modulate cell function with exquisite specificity and limited side effects. Nonetheless, the development of siRNAs as therapeutics will require continued research focused on the critical bottlenecks in the process. To initiate RNAi in vivo, siRNAs are first encapsulated into a delivery vehicle that is typically cationic, to balance charge, and either lipid-like or polymeric in nature. As with other drugs, the vehicle–siRNA complexes are either administered directly to the site of interest (e.g. by injection) to minimize trafficking to nontargeted tissues and maximize local concentration of the drug, or delivered through the bloodstream (intravenous) or gastrointestinal system (oral) to simplify administration. Once delivered to the tissue of interest, the vehicle–siRNA complexes must reach the target cells and cross the plasma membrane to enter the cytoplasm. At this point, the siRNA must be released from the vehicle in order to be recognized by the RNAi machinery. In humans, the primary proteins of the RNAi machinery are Dicer, TAR RNA-binding protein (TRBP) and Argonaute 2 (Ago2). Together with the siRNA, these three proteins form the RNA-induced silencing complex (RISC) and its precursor, the RISC loading complex (RLC). The three proteins bind the siRNA and select which strand of the double-stranded siRNA will become the single-stranded guide strand in RISC. Activated RISC, possessing the single-stranded guide strand, then specifically cleaves an mRNA that contains a sequence complementary to the guide strand. The reduction in mRNA concentration leads to a consequential reduction in protein concentration and the corresponding therapeutic effect. However, many other proteins also recognize double-stranded RNAs (dsRNAs), and many of these proteins are involved in innate immunity and the cellular response to viral infections. Although shorter dsRNAs, like siRNAs, are less immunostimulatory than longer dsRNAs, siRNA therapeutic design must focus on avoiding nonspecific recognition by either cell-surface or cytoplasmic proteins. Understanding how to control potential interactions with nonpathway proteins will greatly expand the therapeutic window for siRNA-based therapeutics. The focus of this minireview series is on the means by which siRNA therapeutics can be generated with the greatest activity and specificity. The three articles focus on different steps in this process: (a) selection of the siRNA sequence most likely to have high activity, (b) in vivo delivery of that siRNA to the tissue and cells of interest, and (c) avoiding side effects associated with the administration of foreign nucleic acids. Current approaches and future challenges are discussed.
The stability of foams: Dependence of observation on the bubble size distribution

The rate of foam collapse owing to interbubble gas diffusion is shown to be a sensitive function of the initial distribution of bubble sizes. Experimental evidence is presented to support these theoretical conclusions. The poor reproducibility of existing foam stability tests can be understood in terms of this sensitivity. The foam surface area decreases as a bilinear exponential function of time. One of the two characteristic time constants appears to be related to a gravity drainage mechanism while the second one is determined by the rates of gas diffusion between bubbles.
Unequal stoichiometry between crosslinking moieties affects the properties of transient networks formed by dynamic covalent crosslinks

A pH responsive system capable of forming a self-healing transient network across the pH 4.5 to 7.5 range is developed by increasing the ratio of phenylboronic acid (PBA) moieties to salicylhydroxamic acid (SHA) moieties incorporated in poly[N-2-hydroxypropyl]methacrylamide polymer backbones. We used particle tracking to assess network formation across the pH range of 4.5 to 7.5 with PBA : SHA stoichiometry of reactive groups of 1 : 1, 5 : 1 and 10 : 1. The 10 : 1 ratio of PBA : SHA forms a transient network across the entire pH range, while the 1 : 1 PBA : SHA materials demonstrate more liquid like behavior at pH 4.5 and forms a transient network only at neutral pH. At pH 7.5 increasing the ratio of PBA to SHA from 1 : 1 to either 5 : 1 or 10 : 1 increases the G′plateau sixty-fold, indicating that the higher probability of crosslink formation impacts the density of crosslinks compared to a 1 : 1 ratio of PBA to SHA. Above pH 5.5 the 5 : 1 and 10 : 1 PBA : SHA gels behaved similarly. Over the temperature range of 10 to 55 °C, the unequal stoichiometric ratios of 10 : 1 and 5 : 1 PBA : SHA transient networks behave similarly, with G′plateau dropping with a corresponding decrease in the characteristic relaxation time. Master curve analysis demonstrates superposition of the 1 : 1, 5 : 1 and 10 : 1 PBA : SHA stoichiometry except under the weakest network conditions (low pH, high temperature) suggesting that the same crosslinking mechanism dominates the network behaviour. The simple and complex viscosity is compared as a function of pH with shear thickening behaviour observed below pH 5.5. The 10 : 1 PBA : SHA crosslinked-network displays self-healing properties after repeated break cycles at both pH 4.5 and pH 7.5 demonstrating that increasing the ratio of PBA to SHA provides a material that can form a self-healing transient network at low pH, where the PBA–SHA crosslink association is weak, to neutral pH where the PBA–SHA complex is stabilized.
Selective detector of 1,2-propylene glycol dinitrate, 1, propylene glycol mononitrate, and 2-propylene glycol mononitrate using gas chromatography/ thermal energy analyzer or liquid chromatography/ electrochemical detection

Abstract Mono- and di-nitrated propylene glycols can be separated and detected using either a gas chromatogph equipped with a nitro-specific thermal energy analyzer (g.c./t.e.a.) or a high-performance liquid chromatograph equipped with an electrochemical detector in the reductive mode (l.c./e.c.). The g.c./t.e.a. exhibits a linear range of three orders of magnitude and provides detection limits in the μg ml −1 range or lower for these three compounds. The l.c./e.c. provides a linear response over two orders of magnitude and is best suited for the determination of propylene glycol dinitrate. Trapping of these glycols on Amberlite XAD-2 resin is discussed.
Scraggly, a new hair loss mutation on mouse Chromosome 19

By use of chlorambucil, we have generated a mouse mutation called scraggly (sgl) that exhibits skin and hair defects. Homozygous mutant mice exhibit hair loss, skin defects, and abnormalities in sebaceous lipid composition. We have constructed a high-resolution genetic map of mouse Chromosome (Chr) 19 that links this mutation to the anonymous DNA marker D19Umi1. An additional cross, (BALB/c × CAST/Ei) F1× BALB/c, was used to map markers around this mutation as well as to map the potential candidate genes, Fgf8 and Cyp17. Allelism tests between sgl and asebia (ab), another hair loss mutation on mouse Chr 19, showed that these genes were separate and distinct.
A pharmacodynamic approach to the evaluation of nitrites in the treatment of angina pectoris.

F EW drugs in any chemical class have so adequately withstood the test of time and achieved the widespread medical acceptance of the nitrites in the treatment of angina pectoris. Reliable pharmacologic studies in laboratory animals supported by decades of favorable clinical experience constitute impressive evidence of the remarkably consistent therapeutic benefits accomplished with octyl nitrite, amyl nitrite and particularly with glyceryl trinitrate (nitroglycerine). At present, no other agent will relieve angina pectoris associated with coronary insufficiency to the same extent and with as few therapeutic failures as nitroglycerine and, consequently, this drug is universally recognized as the yardstick against which are measured the newer long-acting vasodilator compounds as well as the older nitrites considered worthy of reappraisal. For some time, the sublingual route has been the preferred pathway of administration for nitroglycerine and also for certain other vasodilating nitrites. Presumably, ingested material is poorly absorbed and hence less readily available for therapeutic action. The validity of this concept is, however, somewhat open to question in view of the admitted shortcomings and inadequacies of present day methods for evaluating vasodilating drugs. Even a superficial survey of the available literature discloses a variety of conflicting reports concerning the efficacy of different nitrite compounds which may be attributed to failures in experimental design, subjective differences in observation and to the lack of an objective means of detecting vascular dilatation following the administration of an appropriate drug. In addition, the substantial psychogenic factors in angina pectoris compound the usual difficulties encountered in determining the clinical value of any new substance. The challenge of objectivity can only be met by a dynamic approach to the evaluation of nitrites centered about the direct measurement of the circulation and the dilating effects of these compounds on a particular vascular bed. Early experience with a new and objective method for appraising vasodilating properties is presented in this communication.
Experiencing Music Video: Aesthetics and Cultural Context edited by Carol Vernallis (Columbia University Press, 2004)

Many have written about music video's impact on the style and rhetoric of advertising, film, and television, but as Carol Vernallis acknowledges, she is the first to thoroughly analyze the structur...
Cost-minimizing welfare programs

Abstract We study opportunities for lowering the cost of welfare programs by exploiting heterogeneity in the unobservable tastes of welfare recipients. Relying on the inability of cash-based programs to achieve self-selection, we provide circumstances in which it is optimal to provide payments-in- kind. Our model differs from other self-selection models because we allow the recipients the opportunity to trade the subsequent to the receipt of their welfare packages. The presence of unreported cash among the recipient population is considered.
Professionalism, Not Professionals

The proliferation of news and information sources has motivated a need to identify those providing legitimate journalism. One temptation is to go the route of such fields as medicine and law, namely to formally professionalize. This gives a clear method for determining who is a member, with an array of associated responsibilities and rewards. We argue that making such a formal move in journalism is a mistake: Journalism does not meet the traditional criteria, and its core ethos is in conflict with the professional mindset. We thus shift the focus from whether the person is journalist to whether the work satisfies the conditions that characterize legitimate journalism. In explaining those conditions we also look at mechanisms for enhancing the power of persons doing journalism, drawing upon lessons from the labor movement. We also consider a self-declaration model while urging increased literacy from all participants in the news gathering and consuming enterprise.
Documentation Panel: The “Making Learning Visible” Project

Observation and documentation are integral to the early childhood classroom. Observation provides the information necessary for adults to build meaningful relationships with individual children. Documentation panels including photographs, teacher's notes, transcriptions, and artifacts, artfully and prominently displayed, serve as a visual archive of children's learning (Helm, Beneke, & Steinheimer, 1998). Carefully designed panels provide an array of authentic assessment artifacts of children's exploration, while also providing a vehicle for preservice teachers to showcase their understanding of the teaching-learning process. As candidates capture and collect significant moments of learning and reflect on data collected, they develop the practice-teaching inquiry. Inquiry prepares teacher candidates to recognize the value of revisiting previous thinking to help them see relationships between teaching and learning. It is a reflective, intellectually challenging process that is the essence of teacher self-r...
Generation of Synthetic Male and Female Walkers through Manipulation of a Biomechanical Invariant

Synthetic versions of human walkers were generated by computer as point-light displays. Previously it had been determined that the natural gaits of males and females differ according to the extent of movement at the shoulder and the hip. These movements were measured and then used to synthesize the stimuli used in the present study. These stimuli are shown here to be identified by untrained viewers as male when the shoulder movement is greater than the hip movement, and female when the configuration is reversed. Because of the coherence of the display lights representing the shoulder and hip are not necessary for gender recognition, although they do increase performance level. Hypernormality and heavy-footedness in gait are also discussed. Finally, all results are linked to an underlying biomechanical invariant, the center of moment.
The antibiotic treatment of PPROM study: systemic maternal and fetal markers and perinatal outcomes.

Objective We sought to correlate maternal and cord blood cytokine and intercellular adhesion molecule-1 levels with antibiotic exposure and perinatal outcomes after conservatively managed preterm premature rupture of the membranes. Study Design Conservatively managed women with preterm premature rupture of the membranes at 24-32 weeks had blood sampling at randomization (n = 222) and delivery (n = 121). Plasma from these, and umbilical cord blood (n = 196), was stored at –70°C. Interleukin (IL)-6, IL-10, granulocyte colony-stimulating factor (G-CSF), tumor necrosis factor-α, and intercellular adhesion molecule-1 levels were assessed for associations with antibiotic treatment, latency, amnionitis, neonatal sepsis, pneumonia, and composite neonatal morbidity. Results Cord blood IL-6 and G-CSF were higher than maternal levels. Antibiotic treatment lowered only maternal G-CSF ( P = .01). Elevated maternal cytokine levels were associated with delivery within 7 days and with development of chorioamnionitis. All umbilical cord blood markers were increased with amnionitis ( P ≤ .01 for each). No maternal marker was associated with neonatal morbidities. Cord G-CSF and IL-6 were increased with neonatal sepsis within 72 hours of birth ( P = .004 for both), and with composite neonatal morbidity ( P = .001 and .002, respectively). Maternal and umbilical cord cytokine levels demonstrated low predictive values for perinatal outcomes. Conclusion Umbilical cord blood cytokine values are higher than maternal levels, suggesting significant fetal/placental contribution. Maternal and umbilical cord cytokine levels are not adequately predictive to be used clinically.