bluuebunny/crossref_metadata_2025 huggingface dataset:
Lactobacillus and Pediococcus species richness and relative abundance in the vagina of rhesus monkeys (Macaca mulatta)
Authors: Gravett Michael G. , Jin Ling , Pavlova Sylvia I. , Tao Lin
Published: March 2012

Background  The rhesus monkey is an important animal model to study human vaginal health to which lactic acid bacteria play a significant role. However, the vaginal lactic acid bacterial species richness and relative abundance in rhesus monkeys is largely unknown.

Methods  Vaginal swab samples were aseptically obtained from 200 reproductive‐aged female rhesus monkeys. Following Rogosa agar plating, single bacterial colonies representing different morphotypes were isolated and analyzed for whole‐cell protein profile, species‐specific polymerase chain reaction, and 16S rRNA gene sequence.

Results  A total of 510 Lactobacillus strains of 17 species and one Pediococcus acidilactici were identified. The most abundant species was Lactobacillus reuteri, which colonized the vaginas of 86% monkeys. Lactobacillus johnsonii was the second most abundant species, which colonized 36% of monkeys. The majority of monkeys were colonized by multiple Lactobacillus species.

Conclusions  The vaginas of rhesus monkeys are frequently colonized by multiple Lactobacillus species, dominated by L. reuteri.
Vertical transmission of human immunodeficiency virus type 1: insights from studies of multiple pregnancies
Authors: Goedert JJ
Published: March 2012

Because twins share an in utero environment and genetic relationships, similarities and differences between them can provide insight into the epidemiology and natural history of infectious agents, especially human immunodeficiency virus type 1 (HIV‐1). Three projects were summarized: HIV‐1 transmission and AIDS‐free survival in The International Registry of HIV‐Exposed Twins; cloning and sequencing of HIV‐1 proviral sequences in two sets of identical twins; and transmission and natural history of ovine lentivirus (OvLV) in twin lambs. Both HIV‐1 and OvLV transmission were increased for first‐born twins. With HIV‐1, progression to AIDS appeared independent of zygosity. Development of pneumonitis with experimental OvLV infection was highly concordant in monozygotic lambs. Finally, the identical infected twins in one set had intermingling of each infant's HIV‐1 quasispecies, whereas in the second set each twin had its own distinct cluster of quasispecies around a maternal sequence. The studies indicate that most transmission occurs during labor or delivery, and they suggest that immunogenetics may not affect susceptibility to different HIV‐1 quasispecies but may affect the manifestations of specific opportunistic diseases.
Neuropsychiatric disorders of childhood: Tourette's syndrome as a model
Authors: Cohen DJ , Leckman JF , Pauls D.
Published: March 2012

Neuropsychiatric disorders of childhood include conditions such as autism, pervasive developmental disorder and attention deficit hyperactivity disorder. Tourette's syndrome (TS) of chronic, multiple, motor and vocal tics is a model neuropsychiatric disorder with a childhood onset and long‐term, and sometimes life‐long, course. Symptoms and signs change during the course of maturation, and include obsessions, compulsions, attentional difficulties and psychological responses to the disability. These clinical features reflect the interaction between genetic and environmental factors. The localization and cloning of the genetic substrate will allow for detailed study of the pathways from molecular vulnerability to clinical syndrome.
The genetic basis for Prader—Willi syndrome: the importance of imprinted genes
Authors: Brøndum‐Nielsen K.
Published: March 2012

The genetic basis of Prader—Willi syndrome involves imprinted genes on the proximal long arm of chromosome 15. The basic defect appears to be the absence of function of genes that are normally expressed in a monoallelic fashion only from the paternal chromosome. In 60–70% of patients with Prader—Willi syndrome, the genetic defect is a deletion in the area of 15q11–13 on the paternal chromosome. A further 25–30% of patients with Prader—Willi syndrome do not have paternal deletions, the defect being due to uniparental disomy (UPD) for maternal chromosome 15. Paternal deletions and maternal UPD are functionally equivalent, as they both result in the absence of a paternal contribution to the genome in the 15q11–13 region. The SNRPN (small nuclear ribonucleoprotein‐associated polypeptide N) gene has a critical role in the 15q11–13 region, as it is probably part of the putative imprinting centre that regulates the expression of several genes in the Prader—Willi syndrome transcriptional domain. Two further rare causes of Prader—Willi syndrome are imprinting mutations, which are microdeletions or point mutations in the putative imprinting control region, and translocations with their breakpoints in the Prader—Willi syndrome region. □ Prader—Willi syndrome, imprinted genes, mutations, paternal deletions, uniparental disomy
Growth hormone secretagogues in children with altered growth
Authors: Bercu BB , Walker RF
Published: March 2012

A diagnostic test was devised to evaluate pituitary growth hormone (GH) secretory potential. GH secretory dynamics were assessed in children with and without GH deficiency. The GH response was measured to GH‐releasing hormone (GHRH) and the GH‐releasing peptide GHRP‐2, administered sequentially. The mean (± SEM) peak GH response to GHRP‐2 was 20.1 ± 5.5, 63.6 ± 24.9 and 42.2 ± 4.3 μg/l for GH‐deficient, slowly growing non‐GH‐deficient and control children, respectively (p < 0.02 and p < 0.05 for GH‐deficient vs controls and slowly growing children, respectively). Corresponding values for area under the curve (AUC) were 995 ± 371, 2460 ± 953 and 1598 ± 274 μg/l × minute. Peak GH (and AUC) responses to GHRH were 19.6 ± 5.1 μg/l (924 ± 232 μg/l × minute), 31.4 ± 8.4 μg/l (1544 ± 449 μg/l × minute) and 39.8 ± 7.8 μg/l (2201 ± 437 μg/l × minute) for the same three groups, respectively (p < 0.05 for peak GH in GH‐deficient patients vs controls, and p < 0.02 and p < 0.01 for AUC in GH‐deficient vs slowly growing children and controls, respectively). The ratio of the peak GH response to GHRP‐2 and GHRH was similar in all three groups. As these secretagogues stimulate different aspects of hypothalamic function (i.e., they are functional complements), robust GH secretion in response to GHRH or GHRP could suggest adequate endogenous GHRP or GHRH, respectively. A poor response to either GH secretagogue administered individually could represent inadequacy of its endogenous complement. The integrity of functional pituitary elements could be differentiated from inadequate complements by administering both GH secretagogues simultaneously. Application of these principles should allow a better definition of the underlying disorder and provide the basis for therapeutic strategies for those patients with abnormal GH production and/or secretion. □ Diagnostic test, growth hormone‐releasing hormone, growth hormone‐releasing peptide, growth hormone secretogogues
Diagnosis of severe growth hormone (GH) deficiency in young adults who received GH replacement therapy during childhood
Authors: Toogood AA , Shalet SM
Published: March 2012

Between 20% and 87% of young adults who had completed growth hormone (GH) therapy in childhood for a putative diagnosis of GH deficiency (GHD) had normal GH responses to provocative tests when they were retested. Patients with isolated idiopathic GHD were more likely to exhibit normal GH responses at retest in young adult life than were patients with multiple pituitary hormone deficits. When determining which patients should receive GH therapy in adult life, those who have isolated GHD should undergo two tests of GH status, while those with multiple anterior pituitary hormone deficits require only one test. Most information is available for the insulin tolerance test, the arginine stimulation test and the glucagon stimulation test, but more recent methods, such as GH‐releasing hormone in combination with pyridostigmine, are showing promise in the investigation of GHD. In young adults with childhood‐onset GHD, the serum concentration of insulin‐like growth factor I is a useful marker of GH status, and can be used in conjunction with a GH provocative test. The choice of GH provocative test should ultimately depend on the experience and policy developed at the centre performing the assessment. Whichever tests are chosen, each should be validated in subjects known to have hypothalamic‐pituitary disease as well as in normal individuals. □ Childhood‐onset growth hormone deficiency, diagnosis revisited, insulin‐like growth factor I, insulin‐like growth factor binding protein‐3, insulin tolerance test, retesting
Myoglobin‐Induced Apoptosis: Two Pathways Related to Endoplasmic Reticulum Stress
Authors: Zhou Jianhui , Kong Deyang , Zhang Xu , Wang Yuanda , Feng Zhe , Zhang Xueguang , Zhang Li , Wang Yan , Xie Yuansheng , Chen Xiangmei
Published: March 2012

Myoglobin plays an important role in rhabdomyolysis‐induced acute kidney injury (AKI), but the underlying mechanisms are still unclear. The present study investigates myoglobin‐induced apoptosis in HK‐2 cells (human renal proximal tubule cells) to discover some of the mechanisms involved in rhabdomyolysis related AKI. Metmyoglobin is reduced to ferrous myoglobin by ascorbic acid, and then the HK‐2 cells are incubated with ferrous myoglobin. Cell viability is measured by 3‐(4,5)‐dimethylthiahiazo(‐z‐y1)‐3,5‐di‐phenytetrazoliumromide (MTT) assay, and cell injury is tested by supernatant lactose dehydrogenase (LDH). Cell apoptosis is evaluated by fluorescent microscopy of Hoechst staining and by flow cytometry of Annexin V/PI double staining. The apoptosis related protein expression is determined by Western blot. HK‐2 cells were incubated with 200 µM ferrous myoglobin for 24 h, the cell viability decreased and supernatant LDH release increased. Hoechst staining indicated more apoptosis after incubation. Molecular chaperone glucose‐related protein 78 (GRP78), cytochrome C, caspase‐9 started to increase within 3 h after incubation while caspase‐4, caspase‐8 showed no significant change. (iii) When the inositol triphosphate receptor (IP3R) calcium channel was blocked by 2‐aminoethoxydiphenyl‐borinate (2‐APB), caspase‐9 was completely inhibited, GRP78 and caspase‐4 increased dramatically, and caspase‐3 expression was not affected. The apoptosis in HK‐2 cells showed no significant change. Apoptosis in HK‐2 cells incubated with ferrous myoglobin is an endoplasmic reticulum stress induced, IP3R calcium channel mediated, caspase‐9 dependent intrinsic pathway. When the intrinsic pathway was inhibited using an IP3R calcium channel blocker, endoplasmic reticulum stress increased, resulting in the activation of caspase‐4 that cleaved caspase‐3 and generated a substitutive pathway of apoptosis.
Pharmaceutical Patents and Prices of Generics in Morocco and Neighboring Economies
Authors: Driouchi Ahmed , Zouag Nada
Published: March 2012

The objective of this paper is to show the importance of generics in relation to the need to enlarge access to pharmaceuticals in Morocco and its neighbor countries. This is achieved through the introduction of a simplified theoretical market structure model with its pricing implications and its empirical application to available data. The attained results show the effective price decrease of generics relative to the originator drug as means to enlarge access to medicines. This is not the only way for ensuring access to pharmaceuticals, as reduction of the prices of the originals is also important. The study recognizes that the monitoring of pharmaceuticals and their generics are crucial institutional regulatory functions that need to be addressed and emphasized.
Renal cortical and medullary blood flow during modest saline loading in humans
Authors: Damkjær M. , Vafaee M. , Braad P. E. , Petersen H. , Høilund‐Carlsen P. F. , Bie P.
Published: March 2012

Aim

Renal medullary blood flow (RMBF) is considered an important element of sodium homeostasis, but the experimental evidence is incongruent. Studies in anaesthetized animals generally support the concept in contrast to measurements in conscious animals. We hypothesized that saline‐induced natriuresis is associated with changes in RMBF in humans.

Methods

After 4 days of low‐sodium diet, healthy men were subjected to slow intravenous saline loading (12 μmol kg−1 min−1) for 4 h. Renal medullary and cortical blood flow was determined by positron emission tomography with H215O before and after saline infusion using two independent imaging processing methods. One based on a previously published algorithm (voxel peeling) and a novel method based on contrast‐enhanced computed tomography (CT). Blood pressure was measured oscillometrically every 10 min. Cardiac output, heart rate and total peripheral resistance were recorded continuously.

Results

Saline loading increased the urinary sodium excretion by 3.6‐fold (21–76 μmol min−1, P < 0.01). The RMBF was 2.6 ± 0.2 mL g−1 tissue min−1 before and 2.7 ± 0.1 mL g−1 tissue min−1 after saline (n.s.). Cortical blood flow was 3.6 ± 0.1 before and 3.4 ± 0.2 after saline (n.s.). Mean arterial blood pressure did not change measurably (90 vs. 90 mmHg). Bland–Altman analysis suggested agreement between results obtained with voxel peeling (2.6 ± 0.2 mL g−1 tissue min−1) and contrast‐enhanced CT (2.0 ± 0.1 mL g−1 tissue min−1).

Conclusion

In normal humans, changes in RMBF are not necessarily involved in the natriuretic response to modest saline loading. This result is in line with data from conscious rodents.
Management of Recurrent or Persistent Stress Urinary Incontinence after Mid‐urethral Sling
Authors: HAN Ji‐Yeon , LEE Kyu‐Sung , CHOO Myung‐Soo
Published: March 2012

The mid‐urethral sling (MUS) procedure is the most common treatment modality for women with stress urinary incontinence (SUI). Although this procedure is highly successful, 5–20% of patients undergoing MUS experience persistent or recurrent SUI, regarded as surgical failure. However, little is known about methods to evaluate and manage patients who fail MUS procedures. The surgical options in these patients include bulking agent injection, shortening of pre‐implanted tape, pubovaginal sling and repeat MUS. Of these secondary procedures, repeat MUS is the most widely studied, although this has been limited to small case series without long‐term follow‐up. Repeat MUS for prior MUS failure has shown relatively good success rates, ranging from 55 to 90%, with better outcomes obtained using the retropubic rather than the transobturator route. Persistent or recurrent SUI may also be successfully managed with less invasive techniques, such as tape shortening and periurethral injection of a bulking agent. Transurethral injection therapy for primary SUI has shown success rates of more than 65% at 1 year; however, these decreased significantly thereafter to around 30% at long‐term follow‐up. Since the optimal management of recurrent or persistent SUI after MUS has not yet been established, long‐term, prospective, randomized trials are warranted.
Comparative genomics of bacteria from the genus Collimonas: linking (dis)similarities in gene content to phenotypic variation and conservation
Authors: Mela F. , Fritsche K. , de Boer W. , van den Berg M. , van Veen J. A. , Maharaj N. N. , Leveau J. H. J.
Published: March 2012

Collimonas is a genus of soil bacteria comprising three recognized species: C. fungivorans, C. pratensis and C. arenae. Collimonads share the ability to degrade chitin (chitinolysis), feed on living fungal hyphae (mycophagy), and dissolve minerals (weathering), but vary in their inhibition of fungi (fungistasis). To better understand this phenotypic variability, we analysed the genomic content of four strains representing three Collimonas species (Ter14, Ter6, Ter91 and Ter10) by hybridization to a microarray based on reference strain C. fungivorans Ter331. The analysis revealed genes unique to strain Ter331 (e.g. those on the extrachromosomal element pTer331) and genes present in some but not all of the tested strains. Among the latter were several candidates that may contribute to fungistasis, including genes for the production and secretion of antifungals. We hypothesize that differential possession of these genes underlies the specialization of Collimonas strains towards different fungal hosts. We identified a set of 136 genes that were common in all tested Collimonas strains, but absent from the genomes of three other members of the family Oxalobacteraceae. Predicted products of these ‘Collimonas core’ genes include lytic, secreted enzymes such as chitinases, peptidases, nucleases and phosphatases with a putative role in mycophagy and weathering.
Numerical and Experimental Study of the Interaction of a Spark-Generated Bubble and a Vertical Wall
Authors: Jayaprakash Arvind , Hsiao Chao-Tsung , Chahine Georges
Published: March 2012

An understanding of the fundamental mechanisms involved in the interaction between bubbles and structures is of importance for many applications involving cavitation erosion. Generally, the final stage of bubble collapse is associated with the formation of a high-speed reentrant liquid jet directed toward the solid surface. Local forces associated with the collapse of such bubbles can be very high and can exert significant loads on the materials. This formation and impact of liquid jet is an area of intense research. Under some conditions, the presence of gravity and other nearby boundaries and free surfaces alters the jet direction and need to be understood, especially that in the laboratory, small scale tests in finite containers have these effects inherently present. In this work, experiments and numerical simulations of the interaction between a vertical wall and a bubble are carried out using Dynaflow’s three-dimensional code, 3DYNAFS-BEM, which models the unsteady dynamics of a liquid flow including the presence of highly nonlinear time evolving gas-liquid interfaces. The numerical predictions were validated using scaled experiments carried out using spark generated bubbles. These spark bubble tests produced high fidelity test data that properly scale the fluid dynamics as long as the geometric nondimensional parameters, gravity and time are properly scaled. The use of a high speed camera allowing framing rates as high as 50,000 frames per second to photograph the bubbles produced high quality observations of bubble dynamics including clear visualizations of the reentrant jet formation inside the bubble. Such observations were very useful in developing and validating the numerical models. The cases studied showed very good correlation between the numerical simulations and the experimental observations and allowed development of predictive rules for the re-entrant jet characteristics, including jet angle, jet speed, and various geometric characteristics of the jet.
Computational Fluid Dynamic Studies of Vortex Amplifier Design for the Nuclear Industry—II. Transient Conditions
Authors: Francis J. , Birch M. J. , Parker D.
Published: March 2012

In this paper computational fluid dynamics (CFD) techniques have been used to investigate the effect of changes to the geometry of a vortex amplifier (VXA) in the context of glovebox operations in the nuclear industry. These investigations were required because of anomalous behavior identified when, for operational reasons, a long-established VXA design was reduced in scale. The study simulates the transient aspects of two effects: back-flow into the glovebox through the VXA supply ports, and the precessing vortex core in the amplifier outlet. A temporal convergence error study indicates that there is little to be gained from reducing the time step duration below 0.1 ms. Based upon this criterion, the results of the simulation show that the percentage imbalance in the domain was well below the required figure of 1%, and imbalances for momentum in all three axes were all below measurable values. Furthermore, there was no conclusive evidence of periodicity in the flow perturbations at the glovebox boundary, although good evidence of periodicity in the device itself and in the outlet pipe was seen. Under all conditions the modified geometry performed better than the control geometry with regard to aggregate reversed supply flow. The control geometry exhibited aggregate nonaxisymmetric supply port back-flow for almost all of the simulated period, unlike the alternative geometry for which the flow through the supply ports was positive, although still nonaxisymmetric, for most of the period. The simulations show how transient flow structures in the supply ports can cause flow to be reversed in individual ports, whereas aggregate flow through the device remains positive. Similar to the supply ports, flow through the outlet of the VXA under high swirl conditions is also nonaxisymmetric. A time-dependent reverse flow region was observed in both the outlet and the diffuser. It is possible that small vortices in the outlet, coupled with the larger vortex in the chamber, are responsible for the oscillations, which cause the shift in the axis of the precessing vortex core (and ultimately in the variations of mass flow in the individual supply ports). Field trials show that the modified geometry reduces the back-flow of oxygen into the glovebox by as much as 78%. At purge rates of 0.65 m3/h the modified geometry was found to be less effective, the rate of leakage from the VXA increasing by 16–20%. Despite this reduced performance, leakage from the modified geometry was still 63% less than the control geometry.
Randomized Trial of Entecavir plus Adefovir in Patients with Lamivudine-Resistant Chronic Hepatitis B Who Show Suboptimal Response to Lamivudine plus Adefovir
Authors: Lim Young-Suk , Lee Ji-Young , Lee Danbi , Shim Ju Hyun , Lee Han Chu , Lee Yung Sang , Suh Dong Jin
Published: March 2012

A substantial proportion of patients with lamivudine-resistant hepatitis B virus (HBV) show suboptimal virologic response during rescue combination treatment with lamivudine plus adefovir. In this randomized active-control trial, 90 patients with serum HBV DNA levels of >2,000 IU/ml after at least 24 weeks of treatment with lamivudine-plus-adefovir therapy for lamivudine-resistant HBV were randomized to combination treatment with entecavir plus adefovir (ETV+ADV,n= 45) or continuation of lamivudine plus adefovir (LAM+ADV,n= 45) for 52 weeks. At baseline, patients' mean serum HBV DNA level was 4.60 log10IU/ml (standard deviation [SD], 1.03). All 90 patients completed 52 weeks of treatment. At week 52, the proportion of patients with serum HBV DNA levels of <60 IU/ml, the primary endpoint, was significantly higher in the ETV+ADV group than in the LAM+ADV group (n= 13, 29%, versusn= 2, 4%, respectively;P= 0.004). The mean reduction in serum HBV DNA levels from baseline was significantly greater in the ETV+ADV group than in the LAM+ADV group (−2.2 log10IU/ml versus −0.6 log10IU/ml, respectively;P< 0.001). At week 52, additional mutations causing resistance to adefovir or entecavir were analyzed in all patients with detectable HBV DNA by restriction fragment mass polymorphism assays and detected in none of the ETV+ADV group but in 15% of patients in the LAM+ADV group (P= 0.018). Safety and adverse event profiles were similar in the two groups. In conclusion, entecavir-plus-adefovir combination therapy provides superior virologic response and favorable resistance profiles, compared with the continuing lamivudine-plus-adefovir combination, in patients with lamivudine-resistant HBV who fail to respond to lamivudine-plus-adefovir combination therapy.
Attenuated Virulence and Biofilm Formation in Staphylococcus aureus following Sublethal Exposure to Triclosan
Authors: Latimer Joe , Forbes Sarah , McBain Andrew J.
Published: March 2012

Subeffective exposure of
Staphylococcus aureus
to the biocide triclosan can reportedly induce a small-colony variant (SCV) phenotype.
S. aureus
SCVs are characterized by low growth rates, reduced pigmentation, and lowered antimicrobial susceptibility. While they may exhibit enhanced intracellular survival, there are conflicting reports regarding their pathogenicity. The current study reports the characteristics of an SCV-like strain of
S. aureus
created by repeated passage on sublethal triclosan concentrations.
S. aureus
ATCC 6538 (the passage 0 [P0] strain) was serially exposed 10 times to concentration gradients of triclosan to generate strain P10. This strain was then further passaged 10 times on triclosan-free medium (designated strain ×10). The MICs and minimum bactericidal concentrations of triclosan for P0, P10, and ×10 were determined, and growth rates in biofilm and planktonic cultures were measured. Hemolysin, DNase, and coagulase activities were measured, and virulence was determined using a
Galleria mellonella
pathogenicity model. Strain P10 exhibited decreased susceptibility to triclosan and characteristics of an SCV phenotype, including a considerably reduced growth rate and the formation of pinpoint colonies. However, this strain also had delayed coagulase production, had impaired hemolysis (
P
< 0.01), was defective in biofilm formation and DNase activity, and displayed significantly attenuated virulence. Colony size, hemolysis, coagulase activity, and virulence were only partially restored in strain ×10, whereas the planktonic growth rate was fully restored. However, ×10 was at least as defective in biofilm formation and DNase production as P10. These data suggest that although repeated exposure to triclosan may result in an SCV-like phenotype, this is not necessarily associated with increased virulence and adapted bacteria may exhibit other functional deficiencies.
Action of Linezolid or Vancomycin on Biofilms in Ventriculoperitoneal Shunts
In Vitro
Authors: Bayston Roger , Ullas Gautham , Ashraf Waheed
Published: March 2012

Cerebrospinal fluid (CSF) shunts used to treat hydrocephalus have an overall infection rate of about 10% of operations. The commonest causative bacteria are
Staphylococcus epidermidis
, followed by
Staphylococcus aureus
and enterococci. Major difficulties are encountered with nonsurgical treatment due to biofilm development in the shunt tubing and inability to achieve sufficiently high CSF drug levels by intravenous administration. Recently, three cases of
S. epidermidis
CSF shunt infection have been treated by intravenous linezolid without surgical shunt removal, and we therefore investigated vancomycin and linezolid against biofilms of these bacteria
in vitro
. A continuous-perfusion model of shunt catheter biofilms was used to establish mature (1-week) biofilms of
Staphylococcus aureus
,
Staphylococcus epidermidis
(both methicillin resistant [MRSA and MRSE]),
Enterococcus faecalis
, and
Enterococcus faecium
. They were then “treated” with either vancomycin or linezolid in concentrations achievable in CSF for 14 days. The biofilms were then monitored for 1 week for eradication and for regrowth. Enterococcal biofilms were not eradicated by either vancomycin or linezolid. Staphylococcal biofilms were eradicated by both antibiotics after 2 days and did not regrow. No resistance was seen. Linezolid at concentrations achievable by intravenous or oral administration was able to eradicate biofilms of both
S. epidermidis
(MRSE) and
S. aureus
(MRSA). Neither vancomycin at concentrations achievable by intrathecal administration nor linezolid was able to eradicate enterococcal biofilms. It is hoped that these
in vitro
results will stimulate further clinical trials with linezolid, avoiding surgical shunt removal.
Toll-Like Receptor 2 Ligand Pretreatment Attenuates Retinal Microglial Inflammatory Response but Enhances Phagocytic Activity toward Staphylococcus aureus
Authors: Kochan Travis , Singla Anuj , Tosi Joaquin , Kumar Ashok
Published: March 2012

Staphylococcus aureusis a leading cause of severe endophthalmitis, which often results in vision loss in some patients. Previously, we showed that Toll-like receptor 2 (TLR2) ligand pretreatment prevented the development of staphylococcal endophthalmitis in mice and suggested that microglia might be involved in this protective effect (Kumar A, Singh CN, Glybina IV, Mahmoud TH, Yu FS. J. Infect. Dis. 201:255–263, 2010). The aim of the present study was to understand how microglial innate response is modulated by TLR2 ligand pretreatment. Here, we demonstrate thatS. aureusinfection increased the CD11b+CD45+microglial/macrophage population in the C57BL/6 mouse retina. Using cultured primary retinal microglia and a murine microglial cell line (BV-2), we found that these cells express TLR2 and that its expression is increased upon stimulation with bacteria or an exclusive TLR2 ligand, Pam3Cys. Furthermore, challenge of primary retinal microglia withS. aureusand its cell wall components peptidoglycan (PGN) and lipoteichoic acid (LTA) induced the secretion of proinflammatory mediators (tumor necrosis factor alpha [TNF-α] and MIP-2). This innate response was attenuated by a function-blocking anti-TLR2 antibody or by small interfering RNA (siRNA) knockdown of TLR2. In order to assess the modulation of the innate response, microglia were pretreated with a low dose (0.1 or 1 μg/ml) of Pam3Cys and then challenged with liveS. aureus. Our data showed thatS. aureus-induced production of proinflammatory mediators is dramatically reduced in pretreated microglia. Importantly, microglia pretreated with the TLR2 agonist phagocytosed significantly more bacteria than unstimulated cells. Together, our data suggest that TLR2 plays an important role in retinal microglial innate response toS. aureus, and its sensitization inhibits inflammatory response while enhancing phagocytic activity.
Extrahepatic Exoerythrocytic Forms of Rodent Malaria Parasites at the Site of Inoculation: Clearance after Immunization, Susceptibility to Primaquine, and Contribution to Blood-Stage Infection
Authors: Voza Tatiana , Miller Jessica L. , Kappe Stefan H. I. , Sinnis Photini
Published: March 2012

Plasmodium
sporozoites are inoculated into the skin of the mammalian host as infected mosquitoes probe for blood. A proportion of the inoculum enters the bloodstream and goes to the liver, where the sporozoites invade hepatocytes and develop into the next life cycle stage, the exoerythrocytic, or liver, stage. Here, we show that a small fraction of the inoculum remains in the skin and begins to develop into exoerythrocytic forms that can persist for days. Skin exoerythrocytic forms were observed for both
Plasmodium berghei
and
Plasmodium yoelii
, two different rodent malaria parasites, suggesting that development in the skin of the mammalian host may be a common property of plasmodia. Our studies demonstrate that skin exoerythrocytic stages are susceptible to destruction in immunized mice, suggesting that their aberrant location does not protect them from the host's adaptive immune response. However, in contrast to their hepatic counterparts, they are not susceptible to primaquine. We took advantage of their resistance to primaquine to test whether they could initiate a blood-stage infection directly from the inoculation site, and our data indicate that these stages are not able to initiate malaria infection.
HYBRIDIZATION OF GENETIC AND QUANTUM ALGORITHM FOR GENE SELECTION AND CLASSIFICATION OF MICROARRAY DATA
Authors: ABDERRAHIM ALLANI , TALBI EL-GHAZALI , KHALED MELLOULI
Published: March 2012

In this work, we hybridize the Genetic Quantum Algorithm with the Support Vector Machines classifier for gene selection and classification of high dimensional Microarray Data. We named our algorithm GQA SVM. Its purpose is to identify a small subset of genes that could be used to separate two classes of samples with high accuracy. A comparison of the approach with different methods of literature, in particular GA SVM and PSO SVM [2], was realized on six different datasets issued of microarray experiments dealing with cancer (leukemia, breast, colon, ovarian, prostate, and lung) and available on Web. The experiments clearified the very good performances of the method. The first contribution shows that the algorithm GQA SVM is able to find genes of interest and improve the classification on a meaningful way. The second important contribution consists in the actual discovery of new and challenging results on datasets used.
DEMONSTRATION OF COMMUNICATION USING NEUTRINOS
Authors: STANCIL D. D. , ADAMSON P. , ALANIA M. , ALIAGA L. , ANDREWS M. , DEL CASTILLO C. ARAUJO , BAGBY L. , BAZO ALBA J. L. , BODEK A. , BOEHNLEIN D. , BRADFORD R. , BROOKS W. K. , BUDD H. , BUTKEVICH A. , CAICEDO D. A. M. , CAPISTA D. P. , CASTROMONTE C. M. , CHAMORRO A. , CHARLTON E. , CHRISTY M. E. , CHVOJKA J. , CONROW P. D. , DANKO I. , DAY M. , DEVAN J. , DOWNEY J. M. , DYTMAN S. A. , EBERLY B. , FEIN J. R. , FELIX J. , FIELDS L. , FIORENTINI G. A. , GAGO A. M. , GALLAGHER H. , GRAN R. , GRANGE J. , GRIFFIN J. , GRIFFIN T. , HAHN E. , HARRIS D. A. , HIGUERA A. , HOBBS J. A. , HOFFMAN C. M. , HUGHES B. L. , HURTADO K. , JUDD A. , KAFKA T. , KEPHART K. , KILMER J. , KORDOSKY M. , KULAGIN S. A. , KUZNETSOV V. A. , LANARI M. , LE T. , LEE H. , LOIACONO L. , MAGGI G. , MAHER E. , MANLY S. , MANN W. A. , MARSHALL C. M. , MCFARLAND K. S. , MISLIVEC A. , MCGOWAN A. M. , MORFÍN J. G. , DA MOTTA H. , MOUSSEAU J. , NELSON J. K. , NIEMIEC-GIELATA J. A. , OCHOA N. , OSMANOV B. , OSTA J. , PALOMINO J. L. , PARADIS J. S. , PAOLONE V. , PARK J. , PEÑA C. , PERDUE G. , PÉREZ LARA C. E. , PETERMAN A. M. , PLA-DALMAU A. , POLLOCK B. , PROKOSHIN F. , RANSOME R. D. , RAY H. , REYHAN M. , RUBINOV P. , RUGGIERO D. , SANDS O. S. , SCHELLMAN H. , SCHMITZ D. W. , SCHULTE E. C. , SIMON C. , SOLANO SALINAS C. J. , STEFANSKI R. , STEVENS R. G. , TAGG N. , TAKHISTOV V. , TICE B. G. , TILDEN R. N. , VELÁSQUEZ J. P. , VERGALOSOVA I. , VOIRIN J. , WALDING J. , WALKER B. J. , WALTON T. , WOLCOTT J. , WYTOCK T. P. , ZAVALA G. , ZHANG D. , ZHU L. Y. , ZIEMER B. P.
Published: March 2012

Beams of neutrinos have been proposed as a vehicle for communications under unusual circumstances, such as direct point-to-point global communication, communication with submarines, secure communications and interstellar communication. We report on the performance of a low-rate communications link established using the NuMI beam line and the MINERvA detector at Fermilab. The link achieved a decoded data rate of 0.1 bits/sec with a bit error rate of 1% over a distance of 1.035 km, including 240 m of earth.
A NEW PROCEDURE TO ACHIEVE REQUIRED ACCURACY IN COMPUTATIONAL OCEAN ACOUSTICS: THEORETICAL DEVELOPMENT
Authors: LEE DING , CHEN CHI-FANG
Published: March 2012

Ocean acoustic wave propagation can be predicted by applying numerical methods to solve representative wave equations computationally. For this purpose, numerical methods have been introduced; a latest introduction was the Predictor-Corrector Method. An important question arises: Whether or not these numerical methods can produce satisfactory required accurate results? This may cause an accuracy concerned by the users. This paper introduces a new Predict-Correct Procedure to examine whether or not the result meets the accuracy requirement. If not, the procedure can improve the result until it becomes satisfactorily accurate. Discussions will be given on the mathematical and computational developments of the Predictor-Corrector Method as well as the Predict-Correct Procedure. Following that is a discussion on how the Predict-Correct Procedure works. An important part of this paper is devoted to show how this new procedure can achieve the goal of obtaining the required accurate prediction results.
PARRONDO GAMES WITH SPATIAL DEPENDENCE
Authors: ETHIER S. N. , LEE JIYEON
Published: March 2012

Toral introduced so-called cooperative Parrondo games, in which there are N ≥ 3 players arranged in a circle. At each turn one player is randomly chosen to play. He plays either game A or game B. Game A results in a win or loss of one unit based on the toss of a fair coin. Game B results in a win or loss of one unit based on the toss of a biased coin, with the amount of the bias depending on whether none, one, or two of the player's two nearest neighbors have won their most recent games. Game A is fair, so the games are said to exhibit the Parrondo effect if game B is losing or fair and the random mixture (1/2)(A + B) is winning. With the parameter space being the unit cube, we investigate the region in which the Parrondo effect appears. Explicit formulas can be found if 3 ≤ N ≤ 6 and exact computations can be carried out if 7 ≤ N ≤ 19, at least. We provide numerical evidence suggesting that the Parrondo region has nonzero volume in the limit as N → ∞.
COHERENCE RESONANCE BY EITHER INTERNAL NOISE OR EXTERNAL NON-GAUSSIAN NOISE IN INTRACELLULAR CALCIUM OSCILLATIONS
Authors: GONG YUBING , XU BO , WANG LI
Published: March 2012

In this paper, we study the effects of both internal Gaussian noise and external non-Gaussian noise (NGN) on the temporal coherence of intracellular calcium oscillations. It is found that for a small cell volume internal noise can induce coherence resonance (CR) when external noise strength is small, and for a large cell volume external NGN can induce CR when noise strength, correlation time or the deviation from Gaussian distribution is varied. These results show that the calcium oscillation coherence can be optimized by either internal noise or external noise, depending on the cell volume. Furthermore, external NGN can optimize the oscillations in different ways by varying its noise strength, correlation time, or the deviation from Gaussian distribution. These findings imply that CR may appear frequently in the calcium oscillations when internal noise and external NGN coexist. This may help to entirely understand the constructive roles of internal noise and external NGN in the calcium oscillations.
PLANAR, OUTERPLANAR, AND RING GRAPH OF THE COZERO-DIVISOR GRAPH OF A FINITE COMMUTATIVE RING
Authors: AFKHAMI MOJGAN , KHASHYARMANESH KAZEM
Published: March 2012

Let R be a commutative ring with nonzero identity. The cozero-divisor graph of R, denoted by Γ′(R), is a graph with vertex-set W*(R), which is the set of all nonzero and non-unit elements of R, and two distinct vertices a and b in W*(R) are adjacent if and only if a ∉ Rb and b ∉ Ra. In this paper, we characterize all finite commutative rings R such that Γ′(R) is planar, outerplanar or ring graph.
CLEANNESS AND RELATED STRUCTURES IN AMALGAMATED DUPLICATION RINGS
Authors: CHIN ANGELINA , YASSEMI SIAMAK
Published: March 2012

Let R be a commutative ring with identity and let I be an ideal of R. In this paper we study the amalgamated duplication ring R ⋈ I introduced by D'Anna and Fontana. By assuming that (1, i) is a unit in R ⋈ I for every i ∈ I, it is shown that R ⋈ I is uniquely clean (respectively, n-clean, weakly clean, n-good) if and only if R is uniquely clean (respectively, n-clean, weakly clean, n-good). Conditions for R ⋈ I to be almost clean are also discussed.
ECONOMICAL GENERATING SETS FOR THE SYMMETRIC AND ALTERNATING GROUPS CONSISTING OF CYCLES OF A FIXED LENGTH
Authors: ANNIN SCOTT , MAGLIONE JOSH
Published: March 2012

The symmetric group Sn and the alternating group An are groups of permutations on the set {0, 1, 2, …, n - 1} whose elements can be represented as products of disjoint cycles (the representation is unique up to the order of the cycles). In this paper, we show that whenever n ≥ k ≥ 2, the collection of all k-cycles generates Sn if k is even, and generates An if k is odd. Furthermore, we algorithmically construct generating sets for these groups of smallest possible size consisting exclusively of k-cycles, thereby strengthening results in [O. Ben-Shimol, The minimal number of cyclic generators of the symmetric and alternating groups, Commun. Algebra35(10) (2007) 3034–3037]. In so doing, our results find importance in the context of theoretical computer science, where efficient generating sets play an important role.
ON n-CENTRALIZING GENERALIZED DERIVATIONS IN SEMIPRIME RINGS WITH APPLICATIONS TO C*-ALGEBRAS
Authors: DHARA BASUDEB , ALI SHAKIR
Published: March 2012

Let R be a ring with center Z(R) and n be a fixed positive integer. A mapping f : R → R is said to be n-centralizing on a subset S of R if f(x)xn – xn f(x) ∈ Z(R) holds for all x ∈ S. The main result of this paper states that every n-centralizing generalized derivation F on a (n + 1)!-torsion free semiprime ring is n-commuting. Further, we prove that if a generalized derivation F : R → R is n-centralizing on a nonzero left ideal λ, then either R contains a nonzero central ideal or λD(Z) ⊆ Z(R) for some derivation D of R. As an application, n-centralizing generalized derivations of C*-algebras are characterized.
CO-MAXIMAL IDEAL GRAPHS OF COMMUTATIVE RINGS
Authors: YE MENG , WU TONGSUO
Published: March 2012

In this paper, a new kind of graph on a commutative ring R with identity, namely the co-maximal ideal graph is defined and studied. We use [Formula: see text] to denote this graph, with its vertices the proper ideals of R which are not contained in the Jacobson radical of R, and two vertices I1 and I2 are adjacent if and only if I1 + I2 = R. We show some properties of this graph. For example, this graph is a simple, connected graph with diameter less than or equal to three, and both the clique number and the chromatic number of the graph are equal to the number of maximal ideals of the ring R.
SEMICOPRIME PRERADICALS
Authors: RAGGI FRANCISCO , RÍOS JOSÉ , GAVITO SILVIA , RINCÓN HUGO , FERNÁNDEZ-ALONSO ROGELIO
Published: March 2012

We define the concept of "semicoprime" for preradicals and for submodules and we prove some properties that relate both of them. For any ring we define the ultrasocle preradical as a certain join of maximal semicoprime preradicals. It defines a kind of primary decomposition on modules. We compare the greatest semicoprime preradical, the meet of all unipotent preradicals, the socle preradical, and the ultrasocle preradical. We characterize rings which are finite product of simple rings in terms of some of these preradicals. We study the least semicoprime preradical above any preradical and we prove some of its properties. Using "Amitsur constructions" we define some related operators and prove some of their properties.
CONSTRUCTING CHAINS OF PRIMES IN POWER SERIES RINGS, II
Authors: LOPER K. ALAN , LUCAS THOMAS G.
Published: March 2012

For an integral domain D of dimension n, the dimension of the polynomial ring D[ x ] is known to be bounded by n + 1 and 2n + 1. While n + 1 is a lower bound for the dimension of the power series ring D[[ x ]], it often happens that D[[ x ]] has infinite chains of primes. For example, such chains exist if D is either an almost Dedekind domain that is not Dedekind or a one-dimensional nondiscrete valuation domain. The main concern here is in developing a scheme by which such chains can be constructed in the gap between MV[[ x ]] and M[[ x ]] when V is a one-dimensional nondiscrete valuation domain with maximal ideal M. A consequence of these constructions is that there are chains of primes similar to the set of ω1 transfinite sequences of 0's and 1's ordered lexicographically.
STRONGLY CLEAN MATRICES OVER COMMUTATIVE LOCAL RINGS
Authors: CHEN H. , GURGUN O. , KOSE H.
Published: March 2012

An element of a ring is called strongly clean provided that it can be written as the sum of an idempotent and a unit that commute. We characterize, in this paper, the strongly cleanness of matrices over commutative local rings. This partially extend many known results such as Theorem 12 in Borooah, Diesl and Dorsey [Strongly clean matrix rings over commutative local rings, J. Pure Appl. Algebra212 (2008) 281–296], Theorem 3.2.7 and Proposition 3.3.6 in Dorsey [Cleanness and strong cleanness of rings of matrices, Ph.D. thesis, University of California, Berkeley (2006)], Theorem 2.3.14 in Fan [Algebraic analysis of some strongly clean and their generalization, Ph.D. thesis, Memorial University of Newfoundland, Newfoundland (2009)], Theorem 3.1.9 and Theorem 3.1.26 in Yang [Strongly clean rings and g(x)-clean rings, Ph.D. thesis, Memorial University of Newfoundland, Newfoundland (2007)].
DISCRETE VECTOR LATTICES AND THE RANGE OF ORTHOMORPHISMS
Authors: BOULABIAR K. , BUSKES G.
Published: March 2012

We give a counterexample to Theorem 3.2 in Toumi and Toumi [The range of an orthomorphism, J. Algebra Appl.8 (2009) 863–868]. In the process we add a new equivalent statement to those in Theorem 7.48 of Aliprantis and Burkinshaw [Locally Solid Riesz Spaces with Applications to Economics, Mathematical Surveys and Monographs, Vol. 105 (American Mathematical Society, 2003)].
SOME RESULTS ON TORSIONFREE MODULES
Authors: HU JIANGSHENG , DING NANQING
Published: March 2012

We study torsionfree and divisible dimensions in terms of right derived functors of -⊗-. We also investigate the cotorsion pair cogenerated by the class of cyclic torsionfree right R-modules. As applications, some new characterizations of von Neumann regular rings, F-rings and semisimple Artinian rings are given.
DEDEKIND COMPLETIONS OF BOUNDED ARCHIMEDEAN ℓ-ALGEBRAS
Authors: BEZHANISHVILI GURAM , MORANDI PATRICK J. , OLBERDING BRUCE
Published: March 2012

All algebras considered in this paper are commutative with 1. Let baℓ be the category of bounded Archimedean ℓ-algebras. We investigate Dedekind completions and Dedekind complete algebras in baℓ. We give several characterizations for A ∈ baℓ to be Dedekind complete. Also, given A, B ∈ baℓ, we give several characterizations for B to be the Dedekind completion of A. We prove that unlike general Gelfand-Neumark-Stone duality, the duality for Dedekind complete algebras does not require any form of the Stone–Weierstrass Theorem. We show that taking the Dedekind completion is not functorial, but that it is functorial if we restrict our attention to those A ∈ baℓ that are Baer rings. As a consequence of our results, we give a new characterization of when A ∈ baℓ is a C*-algebra. We also show that A is a C*-algebra if and only if A is the inverse limit of an inverse family of clean C*-algebras. We conclude the paper by discussing how to derive Gleason's theorem about projective compact Hausdorff spaces and projective covers of compact Hausdorff spaces from our results.
ENUMERATION OF IDEALS OF SOME NILPOTENT MATRIX RINGS
Authors: EGORYCHEV GEORGY P. , KUZUCUOĞLU FERIDE , LEVCHUK VLADIMIR M.
Published: March 2012

Using the method of integral representation of combinatorial sums we enumerate ideals of certain nilpotent matrix rings.
A METHOD TO COMPUTE SEGRE CLASSES OF SUBSCHEMES OF PROJECTIVE SPACE
Authors: EKLUND DAVID , JOST CHRISTINE , PETERSON CHRIS
Published: March 2012

We present a method to compute the degrees of the Segre classes of a subscheme of complex projective space. The method is based on generic residuation and intersection theory. We provide a symbolic implementation using the software system Macaulay2 and a numerical implementation using the software package Bertini.
HOMOGENEOUS SEMILOCAL GROUP RINGS AND CROSSED PRODUCTS
Authors: FAHMY M. H. , EL-DEKEN SUSAN F. , ABDELWAHAB S. M.
Published: March 2012

Let J(R) be the Jacobson radical of a ring R. Then R is called homogeneous semilocal if R/J(R) is simple artinian. The aim of this paper is to find necessary and sufficient conditions for the group rings and the crossed products to be homogeneous semilocal ring.
ALGEBRAIC LOGIC AND LOGICALLY-GEOMETRIC TYPES IN VARIETIES OF ALGEBRAS
Authors: PLOTKIN BORIS , ALADOVA ELENA , PLOTKIN EUGENE
Published: March 2012

The main objective of this paper is to show that the notion of type which was developed within the frames of logic and model theory has deep ties with geometric properties of algebras. These ties go back and forth from universal algebraic geometry to the model theory through the machinery of algebraic logic. We show that types appear naturally as logical kernels in the Galois correspondence between filters in the Halmos algebra of first order formulas with equalities and elementary sets in the corresponding affine space.