cssi/SciSciGPT-SciSciNet huggingface dataset:
A note on EM algorithm for mixture models

Abstract Expectation–maximization (EM) algorithm has been used to maximize the likelihood function or posterior when the model contains unobserved latent variables. One main important application of EM algorithm is to find the maximum likelihood estimator for mixture models. In this article, we propose an EM type algorithm to maximize a class of mixture type objective functions. In addition, we prove the monotone ascending property of the proposed algorithm and discuss some of its applications.
Interaction of the extrinsic potential-sensitive molecular probe diS-C3-(5) with pigeon heart mitochondria under equilibrium and time-resolved conditions

Abstract Some aspects of the interaction of the extrinsic, potential-sensitive, molecular probe diS-C 3 -(5) with pigeon heart mitochondria are reported in this paper. Binding studies based on fluorimetry indicate that the ratio of the dissociation constant to the maximum number of binding sites, K D n , is larger for succinate-containing mitochondria than that for cyanide-inhibited preparations. These observations suggest that the basis of the energy-dependent diS-C 3 -(5) optical signals is the ejection of the probe from the mitochondrial membrane. A more detailed analysis indicated that the major change in the binding parameters is a reduction in the maximum number of binding sites, n , when a charge gradient is formed at the expense of substrate. Using rapid mixing techniques, the time course of the passive association of diS-C 3 -(5) with mitochondria, that of the glutamate- and ATP-dependent optical signals, and the effect of this probe on the rate at which the energy-dependent cytochrome c oxidase Soret band shift signal develops have been monitored. Retardation the ATP-dependent cytochrome c oxidase Soret band shift signal suggests that the probe readily permeates the mitochondrial membrane. The first-order rate law that the glutamate-dependent signal obeys suggests that the rate-limiting step in the development of this signal is the dissociation of the dye from the mitochondrial membrane or the permeation of this membrane by the probe. The faster phase of the ATP-induced signal likely reflects the initial transfer of dye from the bulk aqueous phase followed by a slower probe permeation process that obeys a first-order rate law. This probe appears to distribute across the mitochondrial membrane in accordance with the transmembrane potential as judged by its effect on the ATP-dependent cytochrome c oxidase Soret band shift signal. DiS-C 3 -(5) also appears to inhibit the NADH dehydrogenase.
Intracranial complications of acute mastoiditis.

Objective: Oral antibiotic use may have changed the incidence and microbiology of otitic intracranial complications. We reviewed cases of acute mastoiditis to document: (1) incidence of intracranial complications; (2) risk factors; and (3) identify pathologic organisms. Methods: A retrospective study of children at a tertiary care children's hospital with acute mastoiditis from July, 1986 through June, 1998. Results: 118 children with acute mastoiditis were identified. Eight patients (6.8%), ages 20 months to 14 years, had intracranial complications related to acute mastoiditis. Three children had a sigmoid sinus thrombosis, two children had an epidural abscess, and two children had both complications of sigmoid sinus thrombosis and epidural abscess, and a sigmoid sinus thrombosis and meningitis was present in one child. Pre-admission oral antibiotics were administered for an average of 10 days in seven of the eight patients. Persistent otorrhea and/or otalgia were present in all patients. Intraoperative cultures were negative in four cases (50%). Organisms isolated included: Streptococcus pneumoniae (2); Proteus mirabilis (1); Pseudomonas aeruginosa (1); and coagulase negative Staphylococcus (1). Multi-drug resistant organisms were documented in only one case. All patients underwent a contrast enhanced CT of the temporal bones and brain. Surgical management included complete mastoidectomy in all patients and a pressure equalization tube in seven of the eight cases. Conclusions: Our review did not document an increase in the incidence of otitic intracranial complications. Persistent otalgia or otorrhea while on oral antibiotics with associated neurologic symptoms are ominous signs suggestive of a complication. Multi-drug resistant organisms are uncommon whereas negative intraoperative cultures are common.
Theoretical considerations in combinations of localized and systemic therapy for neoplastic disease

Abstract A mathematical formulism has been developed to investigate the theoretical considerations of importance in combining localized and systemic treatments for neoplastic disease. The concept of a cell density function describing the distribution of malignant cells throughout the organism allows development of a treatment regimen which will reduce the probability of recurrence to equal levels in all regions, a situation which often will result in optimum use of normal tissue tolerance. Examples presented include the use of systemic chemotherapy and local radiation therapy in the treatment of advanced Hodgkin's Disease and leukemia.
Dynamic stiffness evaluation for reconfigurable machine tools including weakly non-linear joint characteristics:

A systematic procedure is proposed to evaluate the dynamic characteristics of design alternatives for a reconfigurable machine tool (RMT). The procedure is intended to be used in an automated design environment where various design alternatives are generated by kinematic synthesis based on a given task and specification. The evaluation procedure makes use of a substructuring method called non-linear receptance coupling. The coupling method includes the effects of weakly non-linear compliant joints through the use of describing functions for the non-linearities involved. Experimental data obtained from a prototype RMT are used to show the validity of the coupling method. To demonstrate the utility of the proposed evaluation procedure design alternatives are generated based on a lumped parameter model of the RMT and examined with respect to the proposed criteria. It is shown that joint non-linearities may affect dynamic stiffness considerably. It is also shown that the suggested criteria can distinguish various design alternatives with respect to their expected dynamic behaviour.
Improving the cyber security of SCADA communication networks

 SCADA: Supervisory control and data acquisition  SCADA networks enable operating many devices remotely such as track switches, traffic signals, electric circuit breakers, valves, relays, sensors, and water and gas pumps.
The ups and downs of novel antiemetic drugs, part 2: an illustration

ISSUE: Novel antiemetic drugs block either neurokinin-1 receptors or serotonin-3 receptors. Research into the neuropharmacology of vomiting is providing insight into the ways substance P and serotonin interact within the central nervous system that could lead to additional applications of neurokinin-1 antagonists for the treatment of depression and stress.
Sheep grazing effects on coastal Douglas fir forest growth: a ten-year perspective

Abstract Interest in using livestock as a biological control agent to suppress unwanted vegetation in conifer plantations has expanded rapidly in the last 10 years. Additional information concerning the silvicultural implications of livestock grazing, particularly the effects of browsing and competition suppression on timber tree growth, are needed if grazing is to be widely adopted as a forest management tool. Tree diameter and height growth were measured during 1981–1990 for ungrazed and grazed tree stands in a coastal Oregon Douglas fir ( Pseudotsuga menziesii ) forest. Grazed stands were intensively used by a herded flock of 700–900 sheep for 3–4 days each May and August in 1981 and 1982. Understory vegetation phytomass and its utilization by sheep was evaluated using a before-and-after technique in 1981 and 1982. Sheep removed 28% and 64% of new tree lateral branches in 1981 and 1982, respectively. The major effect of browsing, however, appeared to be removal of terminal leaders which reduced 1990 Douglas fir tree height by 61 cm and diameter at breast height (dbh) by 1.9 cm for each terminal removed. Sheep browsed terminal leaders of 38% and 77% of grazed-plantation trees in 1981 and 1982, respectively. Grazing proved very effective in reducing red alder ( Alnus rubra ) establishment and growth. Total tree basal area in 1990 was similar for grazed and ungrazed stands. However, alder trees contributed over 45% of the tree basal area present on ungrazed stands compared to only 19% on grazed stands. Vegetation control by sheep, without associated browsing of terminal leaders, increased 1990 Douglas fir height by 16% and dbh by 34%. The net effect of grazing, reflecting the negative impacts of browsing together with the positive effects of reduced competing vegetation, was to increase the 1990 Douglas fir height by 6% and dbh by 22% on grazed compared to ungrazed timber stands.
Maximizing data preservation in intermittently connected sensor networks

In intermittently connected sensor networks, wherein sensor nodes do not always have connected paths to the base station, preserving generated data inside the network is a new and challenging problem. We propose to preserve the data items by distributing them from storage-depleted data generating nodes to sensor nodes with available storage space and high battery energy, under the constraints that each node has limited storage capacity and battery power. The goal is to maximize the minimum remaining energy among the nodes storing the data items, in order to preserve them for maximum amount of time until next uploading opportunity arises. We first give feasibility condition of this problem by proposing and applying a Modified Edmonds-Karp Algorithm (MEA) on an appropriately transformed flow network. We then show that when feasible solutions exist, finding the optimal solution is NP-hard. We develop a sufficient condition to solve the problem optimally. We then design a centralized greedy heuristic with less time complexity than that of the optimal, which also works when feasibility can not be satisfied and network partitions arise. Via extensive simulations, we show that the heuristic performs comparably to optimal.
Effects of an Affect Bridge for Age Regression

The authors tested tailored hypnotic inductions for age regression with an affect bridge to access meaning-laden events. They used emotional intensity, spontaneity, elaboration, and transitional-object measures to assess the genuineness of the topographic shift to primary process characteristic of hypnotic age regression. An affect bridge was used to access stressful events within the age range of 3 to 6 years. The Stanford Hypnotic Susceptibility Scale, Form C was administered to determine high hypnotizables-reals, (n = 8, scores 9-12) and low hypnotizables-simulators, (n = 8, scores 3 or less). The groups behaved differently on frequency of transitional objects, spontaneity, and intensity but not on elaboration. The hypnotizable-reals but not the simulators produced a plethora of primary-process childlike affective responses that could not be produced by the role-playing simulators.
Electrical properties of multi p-n junction devices

The electrical properties of multi p-n junction devices are analyzed. It is found that this type of device possesses bistable characteristics similar to that of a Shockley diode and thus provides an alternative realization of devices for switching applications. The inherently greater current gains involved in the operations of such a device yield in principle higher breakover voltages and higher holding currents. Furthermore, the incorporation of heterostructures in this device introduces a new degree of freedom in tailoring their switching characteristics. Multi p-n heterojunction devices operating as SCR lasers were fabricated, and the experimental results are presented.
Modeling the isovolumic relaxation period

The isovolumic relaxation period of the left ventricular pressure curve in man has been assumed to be best represented by an exponential decay. To determine which model most closely approximates the empiric pressure data of isovolumic relaxation in man, several models were compared. They included linear, exponential with a zero mmHg pressure asymptote, exponential with a variable asymptote, and second-to fifth-order polynomials. In addition, four different methods of computing parameters of isovolumic relaxation by the exponential model with a variable asymptote were tested. It was found that the isovolumic relaxation period approximates an exponential, that the theoretic asymptote is variable, and that the Levenburg-Marquardt algorithm can be used efficiently to model this period.
Should restoration of small western watersheds be public policy in the United States

Additional research is needed to determine whether restoration of degraded watersheds in the western United States should become large-scale public policy. Numerous small projects have demonstrated that vegetation can be restored, sediment losses halted, and, in some cases, formerly ephemeral streams made perennial. But if all watersheds in a basin were restored, what would be the overall effects both ecologically and economically? For example, if large-scale restoration of small watersheds were conducted in a western river basin, what would be the effects on water yield and quality for the basin as a whole? Would implementing basin-wide watershed restoration be cost-effective? A means of examining this question is to monitor a watershed prior to and during the restoration process and to compare the results to a control watershed. The watersheds would be instrumented such that the ecological processes and water balance could be monitored both instream and within the associated groundwater system. Overall effects would then be subjected to economic and policy analysis, and modeling would be used to extrapolate the new information over the entire basin. These results would then be available to political leaders and government agencies for determining whether large-scale watershed restoration should be public policy.
Failure to Thrive: The Silent Epidemic of the Elderly

Demographic changes have created the need for psychiatric nurses to examine knowledge and practice in the area of geropsychiatry. Older adults present unique challenges. The interaction of biological and psychosocial problems are most evident in the oldest old and necessitate a holistic approach. This report addresses psychosocial causes and treatment of "Failure to Thrive" (FTT) in the elderly. FTT is a label commonly used to describe a complex of nonspecific symptoms that often leads to increased disability and premature death. Psychiatric nurses are challenged to take a leadership role in case finding, as well as assessment and intervention.
Amelioration of ketamine-induced working memory deficits by dopamine D1 receptor agonists

Ketamine has been used in humans to model cardinal symptoms of schizophrenia, including working memory impairments and behavioral disorganization. Translational studies with ketamine in nonhuman primates promise to extend the neurobiological understanding of this model. By establishing the dose-dependent effects of ketamine on spatial working memory and behavior, we sought to test and compare the capacity of antipsychotic and procognitive agents to reverse these symptoms. Behavioral observations were taken following administration of placebo/ketamine (0.1–1.7 mg/kg, intramuscularly) and animals were tested on the spatial delayed response task 15 min post-injection. Pretreatments with risperidone as well as full and partial D1 receptor agonists were tested for their ability to reverse ketamine-induced impairments. Ketamine (median 1.0 mg/kg) produced a profound cognitive impairment and behavioral sequelae reminiscent of positive and negative symptoms. Risperidone within the therapeutic dose range failed to antagonize behavioral or cognitive consequences of acute ketamine but A77636 (0.1 and 1 µg/kg) and SKF38393 (0.1 µg/kg–100 µg/kg) ameliorated the spatial working memory deficit. This effect of A77636 was blocked by the D1 receptor antagonist, SCH39166 (1 and 10 µg/kg). These findings establish a valuable ketamine platform relevant to the treatment of cognitive dysfunction in schizophrenia. The reversal of ketamine-induced working memory deficits by a D1 receptor agonist, but not a commonly prescribed atypical antipsychotic, provides behavioral evidence for significant D1/N-methyl-d-aspartate receptor interactions in prefrontal dysfunction and concurs with suggestions that D1 agonists may be useful in the treatment of cognitive impairments in schizophrenia.
How Intrinsic and Extrinsic Motivations Interact in Selectivity: Investigating the Moderating Effects of Situational Information Processing Goals in Issue Publics' Web Behavior

By employing a unique methodological tool that combines individual-level Web behavior data with survey data, this study explored the effects of two levels of motivations on online information selection and candidate evaluation in an actual election campaign: the moderating effects of situational information processing goals (i.e., extrinsic motivation) on the selectivity and candidate evaluation of members of issue publics (i.e., intrinsic motivation). The results suggest that both intrinsic and extrinsic motivations, and more importantly the interplay of the two, exert significant influences on online political information consumption and candidate evaluation. When the accuracy goal was promoted, issue publics extended their search beyond the issue domains of their personal concerns and considered diverse issues in candidate evaluation. However, an issue public's extremity in candidate evaluation was heightened, in that issue publics paid little attention to the implications of the information when the p...
High frequency, long term regeneration of rice from callus culture☆

Totipotency in cereal tissue cultures is often lost soon after callus initiation, but embryogenic cultures (producing embryo-like forms which develop into complete plants) derived from various plant parts provide long term totipotent cultures. Rice (Oryza sativa vars. Pokkali, IR-36, Mashuri, and Giza-159) calli containing both embryogenic and non-embryogenic regions were initiated from immature embryos and mature seeds cultured on Linsmaier and Skoog (LS) medium, 4% sucrose, 1% agar and variable 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). The most callus was initiated on 1.0 mg/l 2,4,5-T or 2,4-D for Pokkali, on 1.0 mg/l 2,4,5-T for Giza-159, on 2.0 mg/l 2,4,5-T for IR-36 and on 1.0 mg/l 2,4-D for Mashuri. There was not as distinct a visual difference between rice embryogenic and non-embryogenic callus as is found in pearl millet, proso millet and oats. Embryogenic rice callus initiates multiple shoots with roots which develop into fertile plants. Non-embryogenic callus initiates occasional shoots without roots. Twenty percent of embryogenic calli but only 6% of non-embryogenic calli initiated shoots after 50 weeks in culture. Embryogenic calli consistently initiated an average of 9 shoots per 10 cc of callus while non-embryogenic calli initiated 0.4 shoots per 10 cc. Differential shoot initiation indicated that visual selection was accurate in distinguishing between the two callus types.
Granulomatous liver disease and cholestasis.

The presence of granulomas on a liver biopsy opens a broad range of etiologic considerations which require a systematic and organized approach. Hepatic granulomas can be an incidental finding or can represent an observation made as a result of investigation of cholestasis or fever of unknown origin. Granulomatous inflammation in portal spaces, surrounding or near septal or interlobular bile ducts, plays a role in damage to these structures (Fig. 1). The biliary ductal dysfunction that ensues leads to impaired bile secretion and manifestations of cholestasis. This article describes the most common granulomatous disorders of the liver, reviews the pathogenesis of this form of inflammatory response and its varied causes, discusses diagnostic and management strategies, and addresses specific types of hepatic granulomas.
The SCFSkp2 Ubiquitin Ligase Complex Interacts with the Human Replication Licensing Factor Cdt1 and Regulates Cdt1 Degradation

DNA replication initiation is tightly controlled so that each origin only fires once per cell cycle. Cell cycle-dependent Cdt1 degradation plays an essential role in DNA replication control, as overexpression of Cdt1 leads to re-replication. In this study, we investigated the mechanisms of Cdt1 degradation in mammalian cells. We showed that the F-box protein Skp2 specifically interacted with human Cdt1 in a phosphorylation-dependent manner. The SCFSkp2 complex ubiquitinated Cdt1 both in vivo and in vitro. Down-regulation of Skp2 or disruption of the interaction between Cdt1 and Skp2 resulted in a stabilization and accumulation of Cdt1. These results suggest that the SCFSkp2-mediated ubiquitination pathway may play an important role in the cell cycle-dependent Cdt1 degradation in mammalian cells.
Negotiator Risk: Sources of Uncertainty and the Impact of Reference Points on Negotiated Agreements

The settlement of a complex business negotiation inevitably requires the parties to assume substantial risks. Bargaining experiments, including those studying framing effects, have not. Two experiments examined the impact of reference points on negotiator tactics, concessions, and settlements in games with nondeterministic payoffs. In these experiments, subjects negotiated over chances to win a prize rather than directly over shares of the prize. In a reversal of the conventional findings with deterministic games, loss frame negotiators were more cooperative and more likely to settle. In the second experiment, subjects negotiated simultaneously over three linked lotteries, providing an opportunity to create value through risk spreading. In another reversal from deterministic games, loss frame negotiators created more integrative agreements. The impact of framing is clearly not uniform across all types of negotiations. It depends on the source of uncertainty confronting the parties. These experiments further establish and clarify the importance of variable risk preferences in understanding the negotiator framing effect. They also modify the conventional prescriptions given to negotiators and mediators regarding how to frame outcomes.
Evidence That Angiotensin II Is Present in Human Monocytes

Background The purpose of the present study was to determine whether human monocytes and polymorphonuclear leukocytes contain angiotensins I and II. Methods and Results Human mononuclear and polymorphonuclear leukocytes were isolated from blood. To identify angiotensins in human leukocytes, we performed immunocytochemistry using both alkaline phosphatase and fluorescence methods. With light microscopy immunocytochemistry with akaline phosphatase, prominent staining of angiotensin II was observed in mononuclear leukocytes. Angiotensin I was also demonstrated in mononuclear leukocytes, but the signal was less pronounced than for angiotensin II. Polymorphonuclear leukocytes showed very little staining for angiotensin II. Fluorescence immunocytochemistry also demonstrated angiotensin II in mononuclear leukocytes. Angiotensins I and II in homogenate of leukocytes were quantified by radioimmunoassay. The concentration of angiotensins I and II in mononuclear leukocytes was 355±216 (mean±SEM) and 2331±106 fmol/mg...
Dietary Supplements and Sports Performance: Metabolites, Constituents, and Extracts

This is the fifth in a series of six articles to discuss the major classes of dietary supplements (vitamins; minerals; amino acids; herbs or botanicals; and metabolites/constituents/extracts). The major focus is on efficacy of such dietary supplements to enhance exercise or sports performance.
Genotoxicity of the pyrrolizidine alkaloid jacobine in rats.

Abstract Jacobine (JAC) is a pyrolizidine alkaloid (PA) exhibiting adverse hepatic effects similar to those induced by another PA, monocrotaline (MCT). The in vitro reaction kinetics of JAC, however, have been reported to differ quantitively from those of MCT. We report results of experiments to detect and characterize hepatic DNA damage resulting from in vivo administration of JAC (5–60 mg/kg i.p.) to male Sprague-Dawley rats. Hepatic nuclei were isolated and served as the source of DNA in these experiments. Alkaline elution was employed to characterize the type(s) of DNA damage induced. At 4 h post administration, JAC induced significant dose-dependent DNA-DNA interstrand cross-linking over the entire range of doses. Significant DNA-protein cross-linking was also induced by doses of 15–60 mg/kg. No DNA single-strand breaks were detected. Previous studies in this laboratory have shown MCT to induce these same types of lesions. Results from these experiments demonstrate that despite a reported difference in in vitro reaction kinetics, these compounds induce a similar spectrum of DNA damage in the target organ of a susceptible species, where the adverse effects induced are also similar, such similarities are consistent with the involvement of DNA damage in the adverse hepatic effects of PAs.
Enhanced Gas Absorption in the Ionic Liquid 1-n-Hexyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)amide ([hmim][Tf2N]) Confined in Silica Slit Pores: A Molecular Simulation Study

Two-dimensional NPxyT and isostress-osmotic (N2PxyTf1) Monte Carlo simulations were used to compute the density and gas absorption properties of the ionic liquid (IL) 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([hmim][Tf2N]) confined in silica slit pores (25–45 A). Self-diffusivity values for both gas and IL were calculated from NVE molecular dynamics simulations using both smooth and atomistic potential models for silica. The simulations showed that the molar volume of [hmim][Tf2N] confined in 25–45-A silica slit pores is 12–31% larger than that of the bulk IL at 313–573 K and 1 bar. The amounts of CO2, H2, and N2 absorbed in the confined IL are 1.1–3 times larger than those in the bulk IL because of the larger molar volume of the confined IL compared to the bulk IL. The CO2, N2, and H2 molecules are generally absorbed close to the silica wall where the IL density is very low. This arrangement causes the self-diffusivities of these gases in the confined IL to be 2–8 times larger than...
Properties of electron swarms in mercury vapour

The authors report the properties of electron swarms in mercury vapour Townsend discharge. The distribution function, first Townsend ionisation coefficient, mean energy, drift velocity, diffusion coefficient and characteristic energy of electrons in mercury vapour have been computed from the solution of Boltzmann's equation in the range 50<or=E/p0<or=700 V cm-1 Torr-1. The diffusion of electrons and the partition of the remaining energy after ionisation, between the ionising electron and the one produced by ionisation, have been taken into account in the solution of Boltzmann's equation.
Positive Dependence, Upper Sets, and Multidimensional Partitions

Let U be an upper set contained in the finite discrete lattice L = {1,..., D1} ×... × {1,..., Dp}. Representations for U are obtained and shown to correspond to certain multidimensional partitions of integers. It is shown that for p = 3, the number of possible upper sets in L is $\prod_{t=0}^{D3-1} \left{D1 + D2 + t\atop D1}\right\Big/\left{D1 + t\atop D1}\right$ . Various other representation and enumeration results are obtained for related settings. Considered are a variety of applications to multivariate positive dependence and various notions in statistics and reliability theory.
PTSD women Veterans' prevalence of PTSD care.

The Authors Reply—We thank Dr. Lutwak for her interest and comments on our article, “PTSD Risk and Mental Health Care Engagement in a Multi-War Era Community Sample of Women Veterans”.1 We agree that a better understanding of posttraumatic stress disorder (PTSD) risks, incidence, and associated physiological changes are important for informing the care of affected individuals. Several recent studies complement those cited by Dr. Lutwak in furthering our understanding of these important issues and their implications for PTSD care.
Imaging of congenital spine and spinal cord malformations

This article reviews normal embryologic development of the spine and spinal cord and the imaging features of congenital abnormalities of the spine and spinal cord, with particular focus on magnetic resonance imaging. The authors discuss spinal dysraphisms, a heterogeneous group of congenital abnormalities of the spine and spinal cord, and provide information to expand understanding of these complex entities.
Aβ ion channels. Prospects for treating Alzheimer's disease with Aβ channel blockers

Abstract The main pathological features in the Alzheimer’s brain are progressive depositions of amyloid protein plaques among nerve cells, and neurofibrillary tangles within the nerve cells. The major components of plaques are Aβ peptides. Numerous reports have provided evidence that Aβ peptides are cytotoxic and may play a role in the pathogenesis of AD. An increasing number of research reports support the concept that the Aβ–membrane interaction event may be followed by the insertion of Aβ into the membrane in a structural configuration which forms an ion channel. This review summarizes experimental procedures which have been designed to test the hypothesis that the interaction of Aβ with a variety of membranes, both artificial and natural, results in the subsequent formation of Aβ ion channels We describe experiments, by ourselves and others, that support the view that Aβ is cytotoxic largely due to the action of Aβ channels in the cell membrane. The interaction of Aβ with the surface of the cell membrane may results in the activation of a chain of processes that, when large enough, become cytotoxic and induce cell death by apoptosis. Remarkably, the blockage of Aβ ion channels at the surface of the cell absolutely prevents the activation of these processes at different intracellular levels, thereby preserving the life of the cells. As a prospect for therapy for Alzheimer’s disease, our findings at cellular level may be testable on AD animal models to elucidate the potential role and the magnitude of the contribution of the Aβ channels for induction of the disease.
Diagnostic and pathogenetic implications of colorectal carcinomas with multidirectional differentiation: a report of 4 cases

Multidirectional differentiation in colorectal carcinomas is a rare phenomenon. Four cases are reported herein, and their clinical and pathologic characteristics are discussed. Two men and 2 women between the ages of 56 and 76 years who presented with abdominal symptoms are included in this report. Two tumors were located in the right colon, one in the splenic flexure, and one in the descending colon. Distant metastases were evident at presentation in 3 of 4 cases. Histologically, two tumors exhibited neuroendocrine and glandular differentiation; the third tumor was an adenocarcinoma with a sarcomatous component and the fourth tumor showed 3 lines of differentiation (glandular, squamous, and sarcomatoid). In all tumors evaluated, areas of adenocarcinomas were positive for low-molecular weight cytokeratin (CAM 5.2) and mucicarmine, but negative for high-molecular weight cytokeratin (AE3). The squamous cell component was AE3 positive and CAM 5.2 negative. The neuroendocrine component was highlighted by neuroendocrine markers and the sarcomatoid component revealed smooth muscle differentiation. All tumors (except one mucinous tumor) were negative for cytokeratin-20 staining. One patient was on supportive care for terminal metastatic carcinoma, and 2 patients were being treated with adjuvant chemotherapy at the time of this report. Colon carcinoma with multidirectional differentiation is a rare event and may originate from stem cells within the gastrointestinal mucosa, and/or represent the convergence of multiple tumors arising at the same site. This type of tumor should be considered in the differential diagnosis of a bowel biopsy with multiple histopathologic variants.
Isolation of protoplast from callus of Populus euphratica and H+ fluxes across plasma membrane under NaCl stress

We used callus of Populus euphratica Olive to isolate protoplasts, and H+ fluxes across plasma membrane were investigated. The concentration of enzymes for protoplast isolation, e.g. cellulase, pectolyase, macerozyme, hemicellulase, and sorbitol content, incubation time were systemically studied. High yield and viability of protoplast was achieved after 6–8 hours incubation of P. euphratica callus in enzyme solution containing 1.5% (w:v) cellulase R-10, 0.1% (w:v) pectolyase Y-23, 0.2% (w:v) macerozyme R-10, 0.05% (w:v) hemicellulase and 0.75–0.80 mol·L−1 sorbitol. Non-invasively ion selective microelectrode technique was used to access proton fluxes in the absence and presence of NaCl (20 mmol·L−1). Salt-induced transient net H+ efflux was observed in the plasma membrane of P. euphratica cells. The shift of H+ flux response to NaCl shock and the relevance to salt tolerance were discussed.
Natural History of Mass-action in Predator-prey Models: A Case Study from Wolf Spiders and Grasshoppers

Abstract Mass-action models of predator-prey interactions assume that predators encounter prey according to their relative densities as scaled by functional responses, although models seldom specify critical natural history and behavioral mechanisms that ensure that encounters actually occur. As a case study of this assumption, we assess the hypothesis that daily and seasonal activity and microhabitat use by wandering wolf spiders (Lycosidae: Schizocosa) searching for four common grasshopper species (Orthoptera: Acrididae) are coincident under natural conditions. There was great overlap in seasonal phenology and use of microhabitats between spiders and grasshoppers. Grasshoppers that were suitably sized (10–20 mm in length) as prey for spiders were relatively abundant from late spring through summer in this grassland. Three of the four common grasshopper species used microhabitat in a similar way, but differed from a fourth common species, Phoetaliotes nebrascensis. However, when they were active, spiders...
Validity of the independent-processes and isolated-resonance approximations for electron-ion recombination.

We examine the physics behind the continued success of the independent-processes and isolated-resonance approximations in predicting the high-resolution recombination cross sections observed in the current generation of electron-ion experiments. First-step extensions of theory to include the effects of radiative-dielectronic recombination interference, overlapping-resonance structures, and scattering-channel coupling are shown to be relatively small for these recombination experiments.
Association of a MET genetic variant with autism-associated maternal autoantibodies to fetal brain proteins and cytokine expression

The contribution of peripheral immunity to autism spectrum disorders (ASDs) risk is debated and poorly understood. Some mothers of children with ASD have autoantibodies that react to fetal brain proteins, raising the possibility that a subset of ASD cases may be associated with a maternal antibody response during gestation. The mechanism by which the maternal immune system breaks tolerance has not been addressed. We hypothesized that the mechanism may involve decreased expression of the MET receptor tyrosine kinase, an ASD risk gene that also serves as a key negative regulator of immune responsiveness. In a sample of 365 mothers, including 202 mothers of children with ASD, the functional MET promoter variant rs1858830 C allele was strongly associated with the presence of an ASD-specific 37+73-kDa band pattern of maternal autoantibodies to fetal brain proteins (P=0.003). To determine the mechanism of this genetic association, we measured MET protein and cytokine production in freshly prepared peripheral blood mononuclear cells from 76 mothers of ASD and typically developing children. The MET rs1858830 C allele was significantly associated with MET protein expression (P=0.025). Moreover, decreased expression of the regulatory cytokine IL-10 was associated with both the MET gene C allele (P=0.001) and reduced MET protein levels (P=0.002). These results indicate genetic distinction among mothers who produce ASD-associated antibodies to fetal brain proteins, and suggest a potential mechanism for how a genetically determined decrease in MET protein production may lead to a reduction in immune regulation.
Molecular analysis of the replication program in unicellular model organisms

Eukaryotes have long been reported to show temporal programs of replication, different portions of the genome being replicated at different times in S phase, with the added possibility of developmentally regulated changes in this pattern depending on species and cell type. Unicellular model organisms, primarily the budding yeast Saccharomyces cerevisiae, have been central to our current understanding of the mechanisms underlying the regulation of replication origins and the temporal program of replication in particular. But what exactly is a temporal program of replication, and how might it arise? In this article, we explore this question, drawing again on the wealth of experimental information in unicellular model organisms.
Thyroid hormone enhances the ability of serum to accept cellular cholesterol via the ABCA1 transporter.

Objective The goal of this study was to examine the effects of thyroid hormone status on the ability of serum to accept cellular cholesterol.
Heterarchy and hierarchy: a critical appraisal of the "levels of evidence" as a tool for clinical decision making.

human responses, the realities of practice resources, and the wide variety and quality of different forms of information available to us. If practitioners were to use exclusively the standard levels of evidence model in their selection and use of information, they would be making suboptimal decisions based upon less information than that which was relevant, valid, and available for making the decisions. This creates a paradox in that the very model that is intended to support the use of best evidence in decision making, in fact fails to support the formation of a best decision, and may even hinder it, if applied rigidly and exclusively.
Escherichia coli Division Inhibitor MinCD Blocks Septation by Preventing Z-Ring Formation

The min system spatially regulates division through the topological regulation of MinCD, an inhibitor of cell division. MinCD was previously shown to inhibit division by preventing assembly of the Z ring (E. Bi and J. Lutkenhaus, J. Bacteriol. 175:1118–1125, 1993); however, this was questioned in a recent report (S. S. Justice, J. Garcia-Lara, and L. I. Rothfield, Mol. Microbiol. 37:410–423, 2000) which indicated that MinCD acted after Z-ring formation and prevented the recruitment of FtsA to the Z ring. This discrepancy was due in part to alternative fixation conditions. We have therefore reinvestigated the action of MinCD and avoided fixation by using green fluorescent protein (GFP) fusions to division proteins. MinCD prevented the localization of both FtsZ-GFP and ZipA-GFP, consistent with it preventing Z-ring assembly. Consistent with a direct interaction between FtsZ and the MinCD inhibitor, we find that increased FtsZ, but not FtsA, suppresses MinCD-induced lethality. Furthermore, strains carrying various alleles of ftsZ, selected on the basis of resistance to the inhibitor SulA, displayed variable resistance to MinCD. These results are consistent with FtsZ as the target of MinCD and confirm that this inhibitor prevents Z-ring assembly.
Regularization parameter estimation for large-scale Tikhonov regularization using a priori information

Solutions of numerically ill-posed least squares problems Ax~b for [email protected]?R^m^x^n by Tikhonov regularization are considered. For [email protected]?R^p^x^n, the Tikhonov regularized least squares functional is given by J(@s)[email protected][email protected]?"W^2+1/@s^[email protected]?D(x-x"0)@?"2^2 where matrix W is a weighting matrix and x"0 is given. Given a priori estimates on the covariance structure of errors in the measurement data b, the weighting matrix may be taken as W=W"b which is the inverse covariance matrix of the mean 0 normally distributed measurement errors e in b. If in addition x"0 is an estimate of the mean value of x, and @s is a suitable statistically-chosen value, J evaluated at its minimizer x(@s) approximately follows a @g^2 distribution with [email protected]?=m+p-n degrees of freedom. Using the generalized singular value decomposition of the matrix pair [W"b^1^/^2AD], @s can then be found such that the resulting J follows this @g^2 distribution. But the use of an algorithm which explicitly relies on the direct solution of the problem obtained using the generalized singular value decomposition is not practical for large-scale problems. Instead an approach using the Golub-Kahan iterative bidiagonalization of the regularized problem is presented. The original algorithm is extended for cases in which x"0 is not available, but instead a set of measurement data provides an estimate of the mean value of b. The sensitivity of the Newton algorithm to the number of steps used in the Golub-Kahan iterative bidiagonalization, and the relation between the size of the projected subproblem and @s are discussed. Experiments presented contrast the efficiency and robustness with other standard methods for finding the regularization parameter for a set of test problems and for the restoration of a relatively large real seismic signal. An application for image deblurring also validates the approach for large-scale problems. It is concluded that the presented approach is robust for both small and large-scale discretely ill-posed least squares problems.
A formal model for protocol interworking in ISDN

The authors propose a formal model as the the basis to study protocol interworking in ISDN. The interworking of protocols is formally modeled by interactions among networks of communicating finite-state machines (CFSMs). The interactions that may occur in ISDN are then described and defined through two protocol interworking operators: concentration and overlap. >
An analysis of avoidance generalization and food preference transitivity in goldfish, Carassius auratus

To examine the effect of novelty in food selection by fishes, goldfish were trained by feeding them on red or green food pellets. Individual fish and fish in shoals of two, three, and five were then given a choice between equal numbers of familiar pellets and novel (yellow) pellets. In experimental groups, the yellow pellets were soaked in 15% quinine hydrochloride to make them unpalatable. Fish were next presented with equal numbers of familiar and a second novel pellet. It was expected that fish would generalize from their experience with the unpalatable pellets and demonstrate avoidance to sampling a second novel food item. However, as groups, neither controls nor experimentals were reluctant to sample the second novel pellets. Also, fish did not eat significantly more familiar than novel pellets when both were palatable. A third set of experiments examined food preference transitivity in which each pellet type was presented alone and in three pair-wise combinations to individual fish. Although red and...
ARBITRATION PROTOCOLS FOR COMPETING SOFTWARE AGENTS

The exchange of goods and services between bargaining software agents requires new forms of brokering mechanisms which achieve consensus between conflicting parties. Such mechanisms have to be designed in a way that they give rational self-interested agents no incentives for insincere behavior. We introduce an arbiter as third party that resolves conflicting bargaining situations between the agents. To achieve non-manipulative agent behavior, we investigate three arbitration protocols that avoid different forms of manipulations and show how each trades net efficiency for robustness against manipulations. We describe the applicability of the protocols in bilateral bargaining situations and, analyze their robustness against manipulations analytically and by simulations. We compare the protocols with Nash's arbitration1 and the Groves-Clarke tax2 and characterize situations in which our protocols are superior.
A Partial order approach to decentralized control

In this paper we employ the theory of partially ordered sets to model and analyze a class of decentralized control problems. We show that posets provide a natural way of modeling problems where communication constraints between subsystems have a hierarchical structure. We show that such problems have appealing algebraic properties that can be exploited to parameterize the set of stabilizing controllers. While much of the paper is devoted to problems where the plant and controller have identical communication constraints, we also generalize our theory to case where they may have different communication constraints.
The Relationship Between Accurate and Benevolently Biased Serial Argument Perceptions and Individual Negative Health Perceptions

This study explores the extent to which romantic partners’ accurate or benevolently biased (i.e., positive relational illusions) perceptions of one another’s perceived resolvability and conflict strategy usage in serial arguments are linked to multiple measures of individual negative health perceptions. Eighty-four romantic couples separately completed a questionnaire that assessed self- and partner-reports of the serial argument variables and self-reports of negative health perceptions. Benevolently biased serial argument perceptions were significantly associated with more negative health perception variables than were accurate perceptions. These findings offer tentative support for considering dyadic perceptions in relation to individual well-being in the serial argument context.
Patellar taping increases vastus medialis oblique activity in the presence of patellofemoral pain.

A common rehabilitation strategy for patellofemoral pain syndrome (PFPS), which lacks scientific evidence, includes pulling the patella medially with tape to reduce pain and increase the vastus medialis oblique (VMO) muscle activity. The purpose of this study was to examine the effect of various patellar taping procedures on force production, EMG activity of the VMO and vastus lateralis (VL) muscles, and perceived pain experienced by 30 women (27.3 +/- 1.53), half diagnosed with PFPS. The perceived pain, force, and EMG of the VMO and VL, were recorded while subjects performed maximal isokinetic leg presses at 30 degrees /s for each of the following patellar taping conditions: no tape (control), no glide (placebo), medial and lateral glide (experimental). The medial and placebo procedures significantly (P 0.05), it increased the VMO activity and decreased the VL activity in PFPS subjects but had the opposite effect in healthy subjects. The findings suggest that taping the patella medially can contribute positively to PFPS rehabilitation. Because the medial glide and placebo taping conditions had similar effects, it is proposed that the benefits of patellar taping are not due to a change in patellar position but rather due to enhanced support of the patellofemoral ligaments and/or pain modulation via cutaneous stimulation.
Roots: The origins of molecular genetics: One gene, one enzyme

Roots presents articles on landmark discoveries that laid the basis for contemporary molecular and cellular biology. In this article, N. H. Horowitz, Professor Emeritus at the California Institute of Technology, and a former associate of George Beadle's, reviews the work that led to the one gene–one enzyme hypothesis.