cssi/SciSciGPT-SciSciNet huggingface dataset:
Time-average and asymptotically optimal flow control policies in networks with multiple transmitters

We consider M transmitting stations sending packets to a single receiver over a slotted time-multiplexed link. For each phase consisting of T consecutive slots, the receiver dynamically allocates these slots among the M transmitters. Our objective is to characterize policies that minimize the long-term average of the total number of messages awaiting service at the M transmitters. We establish necessary and sufficient conditions on the arrival processes at the transmitters for the existence of finite cost time-average policies; it is not enough that the average arrival rate is strictly less than the slot capacity. We construct a pure strategy that attains a finite average cost under these conditions. This in turn leads to the existence of an optimal time-average pure policy for each phase length T, and to upper and lower bounds on the cost this policy achieves. Furthermore, we show that such an optimal time-average policy has the same properties as those of optimal discounted policies investigated by the authors in a previous paper. Finally, we prove that in the absence of costs accrued by messages within the phase, there exists a policy such that the time-average cost tends toward zero as the phase length T --* oo
Meta‐analysis: interferon improves outcomes following ablation or resection of hepatocellular carcinoma

Aliment Pharmacol Ther 2010; 32: 851–858 Summary Background Hepatocellular carcinoma (HCC) is third most common cause of tumour-related death in the US with hepatitis C virus (HCV) the most common aetiology. Surgical resection and tumour ablation are curative in patients who cannot be transplanted. With native liver having cirrhosis, HCC recurrence is a potential problem. Aim To perform a systematic review and meta-analysis of studies evaluating efficacy of IFN to prevent HCC recurrence after its curative treatment in HCV-related cirrhosis. Methods Ten studies (n = 645, 301 treated with IFN) on the use of IFN after resection or ablation of HCV-associated HCC were analysed. Results Pooled data showed benefit of IFN for HCC prevention with OR (95% CI) of 0.26 (0.15–0.45); P < 0.00001. The proportion of patients surviving at 5 years (n = 505 in 6 studies) was in favour of IFN with OR of 0.31 [(95% CI 0.21–0.46); P < 0.00001]. Data were homogeneous for HCC recurrence (χ2 12.05, P = 0.21) and survival (χ2 6.93, P = 0.44). The benefit of IFN was stronger with sustained virological response compared with nonresponders for HCC recurrence [0.19 (0.06–0.60); P = 0.005] and survival [0.31 (0.11–0.90); P = 0.03]. Conclusion Interferon treatment after curative resection or ablation of HCC in HCV-related cirrhotics prevents HCC recurrence and improves survival.
Detecting salient changes in genomic signals

The functional state of an organism is determined largely by the pattern of the expression of its genes. Salient changes in variation in expression of genes can give clues about important events, such as the onset of a disease. We address the problem of detecting salient inflection points in genomic signals. These are detected using a scale-space decomposition, to be the negative-going zero-crossings of the second derivative of smoothed signals that are preserved over an automatically selected scale. The utility of salient change detection is demonstrated in the automatic identification of the regulatory phase for genes active in the mitotic cell cycle of budding yeast.
Noninvasive Vascular Testing: Clinical Applications and Interpretation Criteria

The noninvasive vascular laboratory has evolved to be an essential element in the evaluation of patients with arterial and venous disease. Based on the interpretation of vascular diagnostic testing, decisions of medical treatment, hospital admission, intervention, or the requirement for additional imaging can be made. Vascular testing should be precise, reproducible, and accurate. Assuring quality noninvasive vascular diagnostics is a constant challenge and is linked to the knowledge and experience of the vascular technologist performing the studies and the physician interpreters, who should utilize appropriate criteria in producing the final report. Duplex ultrasound is essential instrumentation for cerebrovascular, visceral artery, and peripheral venous testing to identify disease and determine its extent and grade severity. For peripheral arterial testing, duplex testing should be combined with segmental pressure measurements, including the measurement of the ankle-brachial systolic pressure index (ABI) for the diagnosis of peripheral arterial disease (PAD). Interpretation of noninvasive vascular testing requires an understanding of ultrasound physics, the instrumentation, testing pitfalls, diagnostic criteria in each testing area, and its accuracy compared to other diagnostic imaging techniques.
In Vitro Demonstration of Dual Light-Driven Na+/H+ Pumping by a Microbial Rhodopsin

A subfamily of rhodopsin pigments was recently discovered in bacteria and proposed to function as dual-function light-driven H(+)/Na(+) pumps, ejecting sodium ions from cells in the presence of sodium and protons in its absence. This proposal was based primarily on light-induced proton flux measurements in suspensions of Escherichia coli cells expressing the pigments. However, because E. coli cells contain numerous proteins that mediate proton fluxes, indirect effects on proton movements involving endogenous bioenergetics components could not be excluded. Therefore, an in vitro system consisting of the purified pigment in the absence of other proteins was needed to assign the putative Na(+) and H(+) transport definitively. We expressed IAR, an uncharacterized member from Indibacter alkaliphilus in E. coli cell suspensions, and observed similar ion fluxes as reported for KR2 from Dokdonia eikasta. We purified and reconstituted IAR into large unilamellar vesicles (LUVs), and demonstrated the proton flux criteria of light-dependent electrogenic Na(+) pumping activity in vitro, namely, light-induced passive proton flux enhanced by protonophore. The proton flux was out of the LUV lumen, increasing lumenal pH. In contrast, illumination of the LUVs in a Na(+)-free suspension medium caused a decrease of lumenal pH, eliminated by protonophore. These results meet the criteria for electrogenic Na(+) transport and electrogenic H(+) transport, respectively, in the presence and absence of Na(+). The direction of proton fluxes indicated that IAR was inserted inside-out into our sealed LUV system, which we confirmed by site-directed spin-label electron paramagnetic resonance spectroscopy. We further demonstrate that Na(+) transport by IAR requires Na(+) only on the cytoplasmic side of the protein. The in vitro LUV system proves that the dual light-driven H(+)/Na(+) pumping function of IAR is intrinsic to the single rhodopsin protein and enables study of the transport activities without perturbation by bioenergetics ion fluxes encountered in vivo.
Indexicality and The Answering Machine Paradox

Answering machines and other types of recording devices present prima facie problems for traditional theories of the meaning of indexicals. The present essay explores a range of semantic and pragmatic responses to these issues. Careful attention to the difficulties posed by recordings promises to help enlighten the boundaries between semantics and pragmatics more broadly.
Addition of Metamucil to gelatin for a realistic breast biopsy phantom

Some expertise as well as hand-eye coordination is required to perform a successful sonographically guided breast biopsy. A simple phantom allows beginners to practice freehand, real-time sonographically guided needle biopsy, aspiration, core biopsy, and needle localization. Several homemade sonographic biopsy phantoms have been proposed, using agar, 1-3 gelatin,4"6 liver, 7,8 and turkey breast. 9 The addition of Metamucil (Proctor & Gamble, Cincinnati, OH) to gelatin results in an echogenic medium that resembles anatomic breast tissue to facilitate the teaching of freehand biopsy techniques of the breast.
Mathematics Strategy Use in Solving Test Items in Varied Formats

Although test scores from similar tests in multiple choice and constructed response formats are highly correlated, equivalence in rankings may mask differences in substantive strategy use. The author used an experimental design and participant think-alouds to explore cognitive processes in mathematical problem solving among undergraduate examinees (N = 64). The study examined the effect of format on mathematics performance and strategy use for male and female examinees given stem-equivalent items. A statistically significant main effect of format on performance was found, with constructed-response items more difficult. The multiple-choice format was associated with more varied strategies, backward strategies, and guessing. Format was found to moderate the effect of problem conceptualization on performance. Results suggest that while for purposes of ranking students on performance, the multiple-choice format may be adequate, for many contemporary educational purposes that seek to provide nuanced informatio...
A note on goodness-of-fit test of continuation ratio logistic regression models under case–control data

Abstract We extend the discussion of Qin and Zhang's [1997. A goodness of fit test for logistic regression models base on case–control data. Biometrika 84, 609–618] goodness-of-fit test of logistic regression under case–control data to continuation ratio logistic regression (CRLR) models. We first showed that the retrospective CRLR model, which is valid for case–control data (the null hypothesis H 0 ) , is equivalent to an I-sample semiparametric model. Then under H 0 , we find the semiparametric profile empirical likelihood estimators of distributions of the covariate conditioning on each response category and use them to define a Kolmogorov–Smirnov type test for assessing the global fit of CRLR models under case–control data. Unlike prospective CRLR models, retrospective CRLR models cannot be partitioned to a series of retrospective binary logistic regression models studied by Qin and Zhang [1997. A goodness of fit test for logistic regression models base on case–control data. Biometrika 84, 609–618].
Psychologic testing in evaluating and understanding organic brain damage and the effects of drugs in children

The clinical picture and the problems of management presented by the child with braindamage frequently are the only indices used to determine the choice and efficacy of treatment. The clinical psychologic examination can often contribute to the management of the brain-injured child. The techniques and meanings of several psychologic test procedures illustrative of the clinical psychologic examination are presented. The results of 3 cases are discussed to illustrate that psychologic tests make a contribution by: (1) identifying areas of personality and intellectual functioning influenced and impaired by the organic brain pathology; (2) determining whether the psychologic impairment is reversible; and (3) assessing the role of personality factors upon the brain damage and drugs employed. Psychologic testing may suggest that socialpsychologic therapies are indicated in addition to the somatic treatment.
Sa1486 Are There Predictive Factors That Assist in Need for Intervention After a Positive Intraoperative Cholangiogram

mean follow-up of 11.4 months (range 1-27) after SEMS placement, thirteen patients (62%) remained jaundice-free and required no repeat biliary interventions. Early stent occlusion ( 30 days) was seen in two patients (10%), occurring at 11 and 18 days. Late stent occlusion ( 30 days) occurred in 6 patients (29%), at a mean 4.9 months (range 2.5-11). These cases were successfully treated through the indwelling SEMS using: repeat SEMS (2), SEMS plastic stent (1), or plastic stents alone (5). In all cases the distal transpapillary end of the indwelling SEMS were easily accessed. Conclusion: Bilateral biliary drainage can be achieved with high technical success rates by sequential, transpapillary placement of a new model SEMS, without temporary plastic stenting to ease delivery of the 2nd SEMS. Placement new stents through the indwelling SEMS is easily accomplished.
Cataracts in the aging rat lens. Morphology and acid phosphatase histochemistry of incipient forms.

Abstract The present investigation deals with morphological and certain histochemical changes that precede and accompany cataracts associated with aging in the rat. The cataracts were of two types: supranuclear (SNC) and posterior subcapsular (PSC). The initial biomicroscopie lesions, which were associated with the auterior and posterior lens suture systems, respectively, were attributed to cytological alterations of the ends of the superficial fiber cells. Cortical alterations common to both types of cataract included segmental cellular swelling, and the formation of assorted globular and multilamellar inclusions. With SNC, large multilamellar bodies corresponded to anterior sutural vacuolar opacities; while swelling and dissociation of the fiber cell bodies were associated with the formation of lamellar separations, lesions which eventually appeared in the peripheral cortex. Posterior subcapsular intercellular vacuoles, many of which developed a lamellated outer structure, were characteristic of the early form of PSC. An acid phosphataso which served as a marker for lysosomal hydrolases was demonstrated in the intercellular spaces of lenses with early forms of degeneration. The major source of the extracellular enzyme appeared to be the Golgi/lysosomal system within the epithelium and cortex, although the cortical smooth endoplasmic reticulum was not ruled out. Our studies support the concept that the swelling and degeneration of cortical fibers occurring in the initial stages of the cataracts might have been caused by intercellularly located hydrolases. The value of the aged rat lens as a model for human senile cataract was reinforced by the many similarities between the murine and human forms of the disease.
Large-Scale Anisotropy in the 2.7-K Radiation with a Balloon-Borne Maser Radiometer at 24.5 GHz

Observations with a high-sensitivity radiometer, covering 80% of the sky, give substantially improved measurements of anisotropy in the 2.7-K radiation. The dipole effect is (T/sub x/, T/sub y/, T/sub z/) = (-3.07 +- 0.17, 0.67 +- 0.09, -0.45 +- 0.09) mK; the Earth's orbital motion through the 2.7-K radiation is detected. No statistically significant quadrupole effect is seen, and a magnitude limit of 0.19 mK is established at the 90% confidence level. Covariance analysis for angular separations between 10/sup 0/ and 180/sup 0/ gives <0.01 (mK)/sup 2/.
Induction of succinyl-coenzyme A:3-oxoacid coenzyme A-transferase during differentiation of 3T3-L1 cells

Differentiation of confluent 3T3-L1 preadipocytes to adipocytes in the presence of dexamethasone and 1-methyl-3-isobutylxanthine for 7 days resulted in a 4-fold increase in the incorporation of acetoacetate-carbon into fatty acids and in the activity of 3-oxoacid CoA-transferase, which catalyzes the first committed step in the conversion of acetoacetate to acetoacetyl-CoA. The increase in enzyme activity was due to an increase in the cellular content of the enzyme, as determined by immunoprecipitation of 3-oxoacid CoA-transferase from 3T3-L1 preadipocytes and adipocytes with rabbit antiserum specific for the rat brain enzyme. The 4-fold increase in enzyme activity was accompanied by a 2.7-fold increase in the average relative rate of synthesis of 3-oxoacid CoA-transferase (between Days 4 and 7). Additionally, the half-life of the enzyme increased 1.9-fold relative to the half-life of total protein, indicating that changes in both synthesis and degradation of 3-oxoacid CoA-transferase are responsible for alterations in its activity. Previous studies on the turnover of other enzymes that are induced during differentiation of 3T3-L1 cells have assigned changes in enzyme synthesis as the primary or sole mechanism for changes in enzyme activity. This report provides the first documentation that both enzyme synthesis and degradation play a role in regulating the enzyme activity of an enzyme during differentiation of 3T3-L1 cells.
On the range of a regenerative sequence

Abstract For a given countable partition of the range of a regenerative sequence {Xn: n ⩾ 0}, let Rn be the number of distinct sets in the partition visited by X up to time n. We study convergence issues associated with the range sequence {Rn: n ⩾ 0}. As an application, we generalize a theorem of Chosid and Isaac to Harris recurrent Markov chains.
Benthic Repopulation of the Raritan River Estuary Following Pollution ABATEMENT1

A total of 69 samples of benthic animals was taken in the lower 20 km of the Raritan River estuary from 1957 to 1960. During 1957, under heavily polluted conditions, no frcshwater spccics wcrc discovered. Of the I7 marinc species found, the barnacle BaEanus improuisus extended 8.5 km above the river mouth; the remaining species were confined to the seaward 4.6 km of the river. In January 1958, a trunk sewer system began operation in the lower Raritan Valley, and pollution was abated in the river. Rapid repopulation of the estuary occurred. The sequence and numbers of freshwater and marinc species invading the estuary and colonizing the bottom sediments were followed in the samples of 1958, 1959, and 1960. The most obvious change in 1958 was the distribution and density of Balanus improuisus. Thcsc barnacles coated all firm substrata in the previously uninhabited section, extending upriver to the limit of salt penetration. The 12 stations sampled in both 1958 and 1959 yielded 6 freshwater and 21 marine species in 1958 and 8 freshwater and 28 marine species in 1959. In 1960, frcshwatcr species continued to increase, but there was a slight decrease in the number of marine species. Dominant components of the freshwater fauna were the oligochaetes Limnodrilus spp., the leech Erpobdella punctata, and the bivalve Sphaerium sp. A density of 7,102 organisms/ma was found at one of the freshwater stations in 1960. Marinc spccics that invaded the river following pollution abatement aro placed in five groups -three of pioneers, one of secondary invaders, and one of progressive pcnetratorson the basis of their year of arrival, penetration, and length of stay. By the end of the study, biotic recovery had so progressed that a plot of the quantitative distribution of spccics illustrated the classic V-shaped curve for estuaries. A similarly shaped curve was obtained for the distribution of population clensitics.
Does parental divergence predict reproductive compatibility

Hybridization between populations or species can have either beneficial or detrimental effects on fitness. If these effects could be predicted based on the genetic or geographical distance between parents, this would be of great use to plant and animal breeders, managers and conservation biologists. The relationship between divergence and compatibility is also increasingly relevant to evolutionary biology, because recent work on the genetic architecture of reproductive isolation has fuelled a renewed interest in speciation rates and processes. Many studies have shown a correlation between parental divergence and both pre- and postzygotic isolation, but this relationship is clearly not strong enough to guide management decisions. Although it has been suggested that the speciation clock might tick at similar rates in different taxa, this appears to be far from true, because the divergence times resulting in hybrid vigor, outbreeding depression or partial reproductive compatibility vary widely both within and among taxonomic groups.
A comparative surface science study of carbide and oxycarbide: the effect of oxygen modification on the surface reactivity of C/W(1 1 1)

Abstract The dehydrogenation of cylohexene to benzene has been used as a probe reaction to study the properties of oxygen-modified C/W(1 1 1) surfaces by temperature programmed desorption, Auger electron spectroscopy and high-resolution electron energy loss spectroscopy. The reactivity of oxygen-modified C/W(1 1 1) depends strongly on the temperature at which the C/W(1 1 1) surface is exposed to oxygen. The oxygen-modified C/W(1 1 1) surface, after exposing to oxygen at 900 K, promotes the selective dehydrogenation of cyclohexene to benzene. The selectivity to benzene on this surface is ∼83%, which is slightly higher than that observed on unmodified C/W(1 1 1) and on Pt(1 1 1). In contrast, oxygen-modified C/W(1 1 1) surfaces with low temperature (
Frequency domain conditions for parameter convergence in multivariable recursive identification

Abstract A multivariable adaptive identifier is designed on the basis of a canonical form leading to a unique set of parameters to identify. Frequency domain conditions for parameter convergence are derived. The sufficient condition to guarantee convergence in all cases is that n + v distinct frequency components be present in each input of the plant, where v is the maximum of the observability indices, and n the order of the plant. On the other hand, the necessary condition requires n + mv distinct frequency components distributed over the inputs, where m is the number of inputs, and at least v frequency components are in each separate input. Through examples, it is shown that convergence may or may not occur for intermediate numbers of frequency components, depending on their location and on the plant parameters.
Calibration and Real Business Cycle Models: An Unorthodox Experiment

Abstract This paper examines the calibration methodology used in real business cycle (RBC) theory. We confront the calibrator with data from artificial economies (various Keynesian macroeconomic models) and examine whether a prototypical real business cycle model, when calibrated to these data sets using standard methods, can match a selected set of sample moments. We find that the calibration methodology does constitute a discriminating test in that the calibrated real business cycle models cannot match the moments from all the artificial economies we study. In particular, we find the RBC model can only match the moments of economies whose moments are close to actual U.S. data.
A Survey of Patient Advocates within the National Cancer Institute's Prostate Cancer SPORE Program: Who are They? What Motivates Them? What Might They Tell Us?

Background. Interacting with patients, researchers, and administrators, patient advocates have a unique vantage point. Yet, few prior studies have sought to understand these individuals or to seek their opinions on cancer issues. Methods. A survey to address the foregoing was developed and mailed to advocates within the National Cancer Institute’s Prostate Cancer SPORE Program. Results. A total of 10 of 19 advocates responded. All were men, most were retired, and all had faced a diagnosis of prostate cancer. Two major themes emerged: (1) the importance of patient education in promoting informed clinical decision-making and (2) a perceived need for patient-centered research by providers and educators. Conclusions. Prostate cancer patient advocates provide a broad range of opinions on the spectrum of cancer care. Similar studies among advocates involved in other malignancies may be worthwhile.
A comment on the use of spectral radius of a matrix

This correspondence calls attention to the misuse of the spectral radius of system matrices in stability analysis. It is demonstrated via examples that \Pi\min{i=1}\max{n} A_{i} may diverge even if \rho(A_{i}) for all i .
Abnormalities of monocyte chemotaxis following thermal injury

Sepsis is the leading cause of morbidity and mortality in severely burned patients. Since normal monocyte function is essential to host defense, the chemotactic responses of monocytes from 25 burned patients were evaluated in vitro. Patients with burns involving <20% of the total body surface had normal monocyte chemotaxis, while monocytes from patients with burns ≥20% had depressed chemotaxis. This defect was most pronounced in patients with burns ≥40%. Analysis of the data as a function of time revealed that monocyte chemotaxis from patients with ≥40% burns was initially near normal, reached a nadir at approximately Day 45, and gradually returned to normal. These studies document that depressed monocyte chemotaxis occurs as a consequence of thermal trauma and indicate that the magnitude of the abnormality is proportional to burn size.
Spectrophotometry (0.33 to 1.07 μm) of 433 Eros and compositional implications

The spectral reflectance (0.33-1.07 micrometers) for the asteroid 433 Eros was determined as a function of rotational phase during January 28-30, and February 15, 1975. Interpretation of absorption features suggests Eros is composed of an undifferentiated assemblage of moderate to high temperature minerals (iron, pyroxene, and olivine, but no carbon). H-type ordinary chondrites are such assemblages, but it would be premature to conclude that Eros is like an H chondrite meteorite in composition until a better understanding is reached of possible physical differences between laboratory powders and asteroid regoliths for metal-bearing assemblages. There are no large-scale major compositional variations on the different sides of Eros.
The Effect of Adjuvants, Pesticide Formulation, and Spray Nozzle Tips on Spray Droplet Size

Many factors, including adjuvants, pesticide formulations, and nozzle tips, affect spray droplet size. It is important to understand these factors as spray droplet size affects both drift and efficacy of pesticides, which is a main concern with pesticide application. A laser particle analyzer was used to determine the spray droplet size and distributions of a range of formulations sprayed through several types of nozzle tips. Nozzles included were extended range flat fan sizes 11003 and 11005 (Spraying Systems XR), air induction flat fan sizes 11005 and 11004 (AI), air induction extended range flat fan size 11005 (AIXR), preorifice flat fan size 11005 (TT), and a second preorifice flat fan size 2.5 (TF). Several deposition/retention adjuvants were studied, including Array, Interlock, In-Place, and Thrust. Another study looked at diflufenzopyr + dicamba (Status, BASF) in combination with several adjuvants. Also, three fungicides were evaluated at differing spray volumes. Results indicated that the droplet size of some nozzle tips is more affected than others by changes in the contents of the spray solution.
Relation of Seasonal Activity Patterns of Valley Pocket Gophers to Temperature, Rainfall, and Food Availability

We analyzed trapping success, reproductive status, surface-heap deposition, surface-access tunneling, and clearing of experimentally plugged tunnels to determine the relation of activity of Thomomys bottae to air temperature, rainfall, and food availability in a mima-mound and vernal-pool habitat in San Diego, California. All activities varied seasonally. Trapping success and clearing of plugged tunnels, reflecting use and maintenance of tunnels, were negatively correlated with air temperature for the preceding week and time since rainfall of ≥2.5 mm. Surface heaps, an indicator of expansion of the main tunnel system, were weakly correlated with the same variables. Production of surface-access tunnels did not correlate with either temperature or rainfall, but peaked late spring-early summer at the end of the growing season. Expansion of the main tunnel system is favored by moist soil and cool temperatures, but probably is triggered by growth of herbaceous food plants and recrudescence of sexual activity, whereas digging of surface-access tunnels is related directly to availability of harvestable aboveground foods.
Biometry/Axial Length in Ophthalmic Ultrasound

Biometry/axial length is an A-scan measurement from theeleading edge of cornea to the leading edge of the retina. This measurement is used to calculate the implant power of the intraocular lens (IOL). The biometry examination is a primary Wand essential part of cataract extraction and IOL surgery.
Effects of Different Magnetic Tapes and Operating Parameters on Lateral Tape Motion in a Linear Tape Drive

The need for increased storage capacity in today's data storage technology has created a continuing need to study the tribological performance of magnetic tape. Lateral tape motion (LTM) is one important area of ongoing tribological research. The objective of the study presented in this article is to determine the effects different magnetic tapes and operating parameters have on LTM. Specifically, the research focuses on LTM in five different tape samples and the effects the varying operating parameters have on LTM. The tapes studied include metal particulate (MP), thin MP, and three advanced metal evaporated (AME) tapes, as well as MP tapes with different edge quality and tapes from staggered packs. The operating parameters studied include tension, speed, and head and bearing setup. Experimental methods used to collect and analyze the LTM data are discussed and the findings are presented.
Bromodeoxyuridine: a diagnostic tool in biology and medicine, Part I: Historical perspectives, histochemical methods and cell kinetics

Bromodeoxyuridine (BrdUrd), a thymidine analogue incorporated into DNA, can be quantified by fluorescent or chromophoric quenching of dyes bound to DNA or with antibodies to BrdUrd. These technologies have been used since the 1970s as tools for measuring DNA synthesis in isolated chromosomes and in cells and tissues. This paper is Part I of a three-part comprehensive review of the literature over the last 20 years (to the end of 1993) describing the histochemical methods for measuring BrdUrd in cells and tissues. Fixation, denaturation and staining procedures are compared for quantifying BrdUrd for microscopy and flow cytometry. Non-immunochemical methods related to the quenching of fluorescent DNA stains by BrdUrd are also described. Methods are described for the comparative assay of cell kinetic parameters by tritiated thymidine and bromodeoxyuridine. The multivariate BrdUrd/DNA assay of Ts, and Tc, and a comparison of recent methods based on the single biopsy bivariate analysis of Tpot, is presented. Recent developments in the use of double halopyrimidine label to determine kinetic parameters are also reviewed.
Normal and Psoriatic Keratinocytes and Fibroblasts Compared in Culture

The ability of psoriatic fibroblasts to stimulate growth of epidermal cells was studied by comparing the capacity of murine 3T3 cells, normal fibroblasts and psoriatic fibroblasts to act as feeder layers for cultured normal human keratinocytes. 3T3 cells consistently gave shorter times to confluency than normal or psoriatic cells which were about the same. The SDS polyacrylamide gel electrophoretic pattern of the fibrous protein was identical irrespective of the feeder layer use. Psoriatic epidermal cells could be grown from single cell suspensions by using 10 −9 M cholera toxin in the medium. The cultured psoriatic keratinocytes grew identically to normal cells and made the same fibrous protein. The psoriatic keratinocytes also grew better on 3T3 cells than normal or psoriatic fibroblasts.
Effect of Modifying Histidine Residues in κ-Casein on Its Stabilizing Ability

Abstract Histidine residues were decreased 0.5 and 1.5 in 5 for 28,000g of diisopropylphosphorylated (DIP) and carboxymethylated (CM) κ -caseinates at pH 5.5. Stabilizing abilities of these κ -caseinates were unchanged. Oxidation with periodate and 2-phenyl-1, 4-dibromoacetoin (PDA) at pH 6.6 decreased stabilizing abilities, which were restored by 0.2 n NaOH. Optical density ratios at 280 m μ and pH 12, and at 220 mμ and pH 7 were 0.07, 0.12, and 0.20 for κ -casein, and PDA- κ -casein alkylated at pH 6.6 and 7.5, respectively, indicating acceptance of more phenyl groups as alkylation progressed. Stabilizing abilities of sterilized and stored κ -caseinates, of which histidine residues were masked by sterilization and storage, were partly restored with 0.2 n NaOH at 25C for 30min. Reoxidation of PDA-alkylated κ -caseins after reduction did not change the gel-filtrated elution patterns obtained with 0.2 n NaOH at 4C on Sephadex G-200. Gel electrophoresis revealed effects of storage on κ -casein that were different from those of rennin action. The peaks moved faster, bound less dye than the control, and bands of the subfractions did not separate clearly. Two fast moving bands separated from the main zone of stored κ -casein in the early stages.
RELIABILISM AND SAFETY

Abstract: Duncan Pritchard has recently highlighted the problem of veritic epistemic luck and claimed that a safety-based account of knowledge succeeds in eliminating veritic luck where virtue-based accounts and process reliabilism fail. He then claims that if one accepts a safety-based account, there is no longer a motivation for retaining a commitment to reliabilism. In this article, I delineate several distinct safety principles, and I argue that those that eliminate veritic luck do so only if at least implicitly committed to reliabilism.
Juvenile survival in a unisexual/sexual complex of mollies

Unisexual species like the gynogenetic Amazon molly, Poecilia formosa, enjoy a twofold advantage over sexual species, because they do not produce males. Therefore, unisexuals should be able to outcompete and consequently, replace sexual species. For sperm-dependent (gynogenetic) unisexuals this creates a paradox: they cannot replace their sexual hosts without eradicating themselves. Thus, mechanisms must be in place to stabilize such mating systems. We assessed juvenile survivorship between asexual P. formosa and sexual Poecilia latipinna as a possible factor allowing for persistence and coexistence between the two sympatric species. Offspring of gynogenetic Amazon mollies did not differ significantly in survivorship compared to their sexual host, the Sailfin molly, P. latipinna. The presence of an adult female significantly reduced survival in both species, suggesting that filial cannibalisms operates in this system, but does not appear to play a role in stabilizing mixed sexual/asexual populations.
Excision-activated chloride channels in cultured postnatal rat hippocampal neurons

Abstract Chloride permeable intermediate conductance single channel events activated on patch excision were found in outside-out patches from cultured postnatal hippocampal neurons. A majority of the channels had a conductance of 83 ± 2.1 pS when recorded in a symmetrical TEAC1 solution. Two other populations of channels with conductance values of 62 ± 2.1 pS and 145 ± 1.9 pS were also observed. The reversal potentials for these intermediate conductance Cl − channels coincided with that of the GABA activated channels. The channels characteristically appeared 5–15 min after patch excision, suggesting that these channels may be blocked by some diffusible factors under physiological conditions. Based on the measurements of channel burst durations while the channel was partially blocked, and the channel open times after complete relief from the block, the mechanism of blockade does not appear to be a simple open channel blockade. The high prevalence and its potential regulation by cytosolic factors suggest an important physiological role for these Cl − channels coupling neuronal excitability with cellular metabolism.
Lewis acid properties of zinc(II) in Its cyclen complex. The structure of [Zn(cyclen)(S=C(NH2)2](ClO4)2 and the bonding of thiourea to metal ions. Some implications for zinc metalloenzymes.

The structure of the complex [Zn(cyclen)Tu](NO3)2 (1) is reported (cyclen = 1,4,7,10-tetraazacyclododecane; Tu = thiourea): orthorhombic, space group P212121, a = 11.4170(11) A, b = 12.1995(11) A, c = 12.5299(12) A, Z = 4, R = 0.0504. The coordination of the cyclen is the same as that found for other similar ZnII complexes, with square pyramidal coordination around the ZnII and mean Zn−N bond lengths of 2.16 A. The coordinated Tu occupies the axial coordination site, with Zn−S = 2.31 A. The Zn−S−C−N torsion angle, involving the coordinated Tu, of 75.4° is unusually large, because such torsion angles involving coordinated Tu are normally closer to 0°. The bonding between Zn and S is discussed in terms of overlap with the p orbitals on S, which favors the eclipsed (Zn−S−C−N torsion = 0°) mode of coordination of Tu. The energies of eclipsed and staggered modes (Zn−S−C−N = 90°) of coordination of Tu to metal ions are examined by means of ab initio calculations, using the STO-3G basis set. It is concluded tha...
Preschool Children's Attitudes Toward Older Adults: Comparison of Intergenerational and Traditional Day Care

Increasingly, attention has focused on the impact of intergenerational programming. Using a static group comparison design, this study examines preschoolers' attitudes toward older adults by comparing children in a shared site intergenerational program and those in traditional day care. Children were shown sketches of an older man and an older woman and were asked to describe them in terms of specific attributes. A two-group discriminant analysis was conducted to assess differences between the two programs yielding significant differences, with 82% of children correctly classified regarding program participation. Overall, attitudes toward older adults were more positive in the intergenerational program compared to the traditional program. In addition, preschoolers in the intergenerational program viewed older adults as healthy compared with preschoolers in a traditional program. Implications of these findings are examined.
Murine peptidoglycan recognition proteins PglyrpIα and PglyrpIβ are encoded in the epidermal differentiation complex and are expressed in epidermal and hematopoietic tissues

Peptidoglycan recognition proteins (PGRPs or PGLYRPs) are pattern recognition molecules that are found in insects and mammals and are critical for innate immune responses. PGRPs bind peptidoglycan, a ubiquitous component of bacterial cell walls, and are involved in killing bacteria, degrading peptidoglycan, and initiating host defense reactions. Relatively little is known about the four mammalian PGRPs. In this article, we report the sequences of mouse PglyrpIalpha and PglyrpIbeta and provide details of their expression in wild-type mouse tissues. PglyrpIalpha and PglyrpIbeta are encoded within the epidermal differentiation complex on mouse chromosome 3F. Both genes are expressed in epidermal and hematopoietic tissues. PglyrpIbeta is expressed in each of 16 tissues tested, while PglyrpIalpha expression is limited to fewer tissues, including the lung and spleen as well as several tissues of the digestive system. Both proteins are expressed in epithelial cells throughout the gut, and immunohistochemical staining shows expression in salivary glands, the squamous epithelium of the stomach, and the villi of the jejunum. Immunohistochemical staining further shows expression of both PglyrpIalpha and PglyrpIbeta in macrophages in the spleen. PglyrpIalpha is not expressed in resting RAW264.7 macrophage-like cells, but is induced by stimulation with lipopolysaccharide. PglyrpIbeta is constitutively expressed in RAW264.7 cells and is unaffected by lipopolysaccharide or peptidoglycan stimulation. Computational and experimental data suggest that these proteins are secreted. This work provides a step toward understanding the roles of PglyrpIalpha and PglyrpIbeta in host defense and chronic inflammatory conditions induced by bacteria or their components.
Characteristics of single-grit rotating scratch with a conical tool on pure titanium

Single-grit rotating scratch tests have been conducted with a conical diamond tool on pure titanium. The force profiles during the scratch event were captured using high frequency force transducers. The mechanisms of material removal have been characterized by optical and scanning electron microscopes. It was observed that the adhesion between the tool and the deformed material and the hardening properties of material play active roles in the scratching process. Adiabatic shear band (ASB) formation followed by cracking was observed to be responsible for the material removal during scratching. The overall frictional coefficient (OFC) was found to oscillate strongly at the beginning and at the end of the scratch, but increased steadily in the middle of the scratch. The size dependence of overall specific energy was observed and was mainly attributed to the competition between hardening and softening during the scratching process. Instantaneous specific energy and instantaneous scratch hardness have been introduced to characterize the process. These parameters were found to be sensitive to the depth of cut, thus validating the close correlation to the size effect of overall specific energy.
An open source framework to add spatial extent and geospatial visibility to Big Data

Advancement in the field of computing and remote handheld devices has made the process of collecting geospatial data easy. Most of the time researchers and scientists have easy access to these data as well. However, the process of extracting and processing a large volume of data from several sources can be very time consuming and difficult. In most cases scientists rely on expensive proprietary software [1]. This paper discusses how Computational Scientists at Oak Ridge National Laboratory are extracting, normalizing, and processing millions of geospatial data points from multiple data sources and integrating them into a common data format which helps user to find and access these data using a flexible visualization-based user interface.
Transitory postnatal hemolysis of calf red cells by amino acids

Among the amino acids which can be solubilized to give a concentration of 300 mm at near physiological pH, histidine and proline caused a complete hemolysis of newborn calf but not of adult cow red cells within 20 to 30 minutes at 38 degrees C. While hydroxyproline, valine, and serine resulted in a partial lysis of calf cells, threonine, glutamine, and glycine were ineffective. In this communication, emphasis has been focused on the mode of the lytic process by histidine which was found to be affected by several governing parameters including the pH, temperature and the extracellular salts in the solution. Unlike human red cells suspended in isotonic histidine, both calf and cow cells lost little Na and K ions. In the presence of 300 mm histidine, both calf and cow cells displayed an instantaneous uptake of histidine amounting to 20 to 45 mumoles/ml RBC followed by a slow influx rate of 0.25 to 0.5 mumoles/ml RBC X min. The extent to which histidine entry was allowed by the cell was counterbalanced by Cl- efflux, resulting in little change in cell volume prior to hemolysis. Moreover, histidine-induced hemolysis can be prevented by 1 mm or lower PCMBS without a discernible effect on histidine influx suggesting a possible membrane lesion or damage at the outer surface of the cell. Hemolysis induced by histidine decreased substantially when a calf reached two months of age at which time the red cells containing the fetal hemoglobin are virtually depleted. The results of hemoglobin electrophoresis obtained during this postnatal period revealed that those cells resistant to histidine hemolysis almost invariably contain the adult type hemoglobin suggesting a selective, specific action of the amino acids on the fetal cells.
Chest pain. How serious is it

The very thought of chest pain often brings terror to patients and health care providers. Chest pain typically invokes a "worst case" scenario of massive myocardial infarction (MI) resulting from cardiovascular disease (CD) and requiring immediate medical attention. However, chest pain is a common complaint suffered by most people at some time in their lives. People complaining of chest pain may be young, middle-aged, or elderly, and they may or may not be under a health care provider's care. Chest pain may be a symptom of a variety of disorders other than CD. Therefore it is helpful to differentiate quickly between the types of chest pain to determine whether immediate assistance is necessary.
Phosphorylation and modulation of recombinant GluR6 glutamate receptors by cAMP-dependent protein kinase

GLUTAMATE-GATED ion channels mediate most excitatory synaptic transmission in the central nervous system and play crucial roles in synaptic plasticity, neuronal development and some neuropathological conditions1–3. These ionotropic glutamate receptors have been classified according to their preferred agonists as NMDA (N-methyl-D-aspartate), AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionate) and KA (kainate) receptors4. On the basis of sequence similarity and pharmacological properties, the recently cloned glutamate receptor subunits have been assigned as components of NMDA (NMDAR1, 2A–D), AMPA (GluRl–4) and KA (GluR5–7, KA1, KA2) receptors5–7. Protein phosphorylation of glutamate receptors by protein kinase C and cyclic AMP-dependent protein kinase (PKA) has been suggested to regulate their function8–18, possibly playing a prominent role in certain forms of synaptic plasticity such as long-term potentiation19 and long-term depression9. Here we report that the GluR6 glutamate receptor, transiently expressed in mammalian cells, is directly phosphorylated by PKA, and that intracellularly applied PKA increases the amplitude of the glutamate response. Site-specific mutagenesis of the serine residue (Ser 684) representing a PKA consensus site completely eliminates PKA-mediated phosphorylation of this site as well as the potentiation of the glutamate response. These results provide evidence that direct phosphorylation of glutamate receptors modulates their function.
Lexico-semantic structure and the word-frequency effect in recognition memory

The word-frequency effect (WFE) in recognition memory refers to the finding that more rare words are better recognized than more common words. We demonstrate that a familiarity-discrimination model operating on data from a semantic word-association space yields a robust WFE in data on both hit rates and false-alarm rates. Our modeling results suggest that word frequency is encoded in the semantic structure of language, and that this encoding contributes to the WFE observed in item-recognition experiments.
Protein calculations on parallel processors. II: Parallel algorithm for the forces and molecular dynamics

We describe two algorithms for the parallel calculation of a CHARMm-like force field in macromolecules. For a molecule with a given number of atoms, we show that there is an optimal number of processors leading to a minimum computation time. At the optimum, both the number of processors and the computation time are proportional to the number of atoms. © 1992 by John Wiley & Sons, Inc.
Biological Functions of DNA Methyltransferase 1 Require Its Methyltransferase Activity

DNA methyltransferase 1 (DNMT1) has been reported to interact with a wide variety of factors and to contain intrinsic transcriptional repressor activity. When a conservative point mutation was introduced at the key catalytic residue, mutant DNMT1 failed to rescue any of the phenotypes of Dnmt1-null embryonic stem (ES) cells, which indicated that the biological functions of DNMT1 are exerted through the methylation of DNA. ES cells that expressed the mutant protein did not survive differentiation. Intracisternal A-particle family retrotransposons were no longer methylated and were transcribed at high levels. The proper localization of DNMT1 depended on normal genomic methylation, and we discuss the implications of this finding for epigenetic dysregulation in cancer.