550 research outputs found
Measurement of pressure effects on the magnetic and the magnetocaloric properties of the intermetallic compounds R(Co1-xSix)2 [R=Dy and Er]
The effect of external pressure on the magnetic properties and magnetocaloric
effect of R(Co1-xSix)2 [R= Er, Dy and x=0, 0.025 and 0.05] compounds has been
studied. The ordering temperatures of both the parent as well as the Si
substituted compounds are found to decrease with pressure. In all the
compounds, the critical field for metamagnetic transition increases with
pressure. It is seen that the magnetocaloric effect in the parent compounds is
almost insensitive to pressure, while there is considerable enhancement in the
case of Si substituted compounds. Spin fluctuations arising due to the
magnetovolume effect play a crucial role in determining the pressure dependence
of magnetocaloric effect in these compounds. Analysis of the magnetization data
using the Landau theory has shown that the magnitude of the Landau coefficient
(C3) decreases with Si concentration whereas it is found to increase with
pressure. The isothermal magnetic entropy change is found to behave in the same
manner as C3, both with Si concentration (at ambient pressure) as well as with
the applied pressure.Comment: 15 pages, 5 figure
Behandeling en stigmamanagement bij opzettelijke zelfverwonding: het smalle pad tussen te veel en te weinig interveniëren
Opzettelijke zelfverwonding wordt gedefinieerd als de intentionele directe beschadiging van het eigen lichaam, zonder bewuste suïcidale intentie. De behandeling varieert van gedwongen opname in een psychiatrische instelling (in het Britse Gemenebest), tot een permissieve aanpak zonder behandeling en uiteenlopende behandelingsmogelijkheden er tussenin. Eerst wordt de gepastheid van de mate van interveniëren besproken in functie van verschillende diagnosen. Het tweede gedeelte van het artikel bespreekt het advies dat door hulpverleners verstrekt wordt aangaande de omgang met wonden en littekens en aangaande de mogelijkheden voor een (gewezen) zelfverwonder om het stigma van een deviante identiteit te vermijden. Een rondvraag bij Belgische hulpverleners bracht aan het licht dat velen onder hen adviseren om littekens te verbergen, terwijl er anderzijds aanwijzingen zijn dat niet-verbergen een teken van herstel is. Aangezien verbergen en smoesjes verzinnen ook kunnen leiden tot de instandhouding van een deviante identiteit, wordt gewezen op meer gepaste vormen van stigmamanagement
Pathogens that cause acute febrile illness among children and adolescents in Burkina Faso, Madagascar and Sudan
BACKGROUND: The etiology and optimal clinical management of acute febrile illness (AFI) is poorly understood. METHODS: Blood samples taken from study participants with acute fever (>/=37.5 degrees C) or a history of fever and recruited into the previous Typhoid-Fever-Surveillance-in-Africa (TSAP) study were evaluated using a polymerase chain reaction (PCR)-based TaqMan-Array Card designed to detect a panel of bacterial, viral and parasitic pathogens. Clinical metadata were also assessed. RESULTS: A total of 615 blood samples available for analysis originated from Burkina Faso (n=53), Madagascar (n=364) and Sudan (n=198) and were taken from participants ranging from 0-19 years of age. Most individuals [86.4% (531/615)] presenting at healthcare facilities were outpatient adolescents (11-19 years-old). Leading clinical diagnoses were respiratory tract infections [45.9% (282/615)], malaria [27.3% (168/615)], and gastrointestinal tract infections [10.7% (66/615)]. Through the TaqMan-Array Card, at least one pathogen was detected in 62% (33/53), 24% (86/364), and 60% (118/198) of specimens, from Burkina Faso, Madagascar and Sudan, respectively. The leading identified pathogen overall was Plasmodium spp., accounting for 47% (25/53), 2.2% (8/364) and 45% (90/198) of AFI at respective sites. In Madagascar, dengue virus was the most prevalent pathogen (10.2%). Overall, 69% (357/516) of patients with clinical diagnoses of malaria, respiratory, or gastrointestinal infections were prescribed a WHO-guideline-recommended empiric antibiotic,whereas only 45% (106/237) of patients with pathogens detected were treated with an antibiotic exerting likely activity. CONCLUSIONS: A PCR-approach for identifying multiple bacterial, viral and parasitic pathogens in whole blood unveiled a diversity of previously undetected pathogens in AFI cases and carries implications for the appropriate management of this common syndrome
Fermi-liquid instabilities at magnetic quantum phase transitions
This review discusses instabilities of the Fermi-liquid state of conduction
electrons in metals with particular emphasis on magnetic quantum critical
points. Both the existing theoretical concepts and experimental data on
selected materials are presented; with the aim of assessing the validity of
presently available theory. After briefly recalling the fundamentals of
Fermi-liquid theory, the local Fermi-liquid state in quantum impurity models
and their lattice versions is described. Next, the scaling concepts applicable
to quantum phase transitions are presented. The Hertz-Millis-Moriya theory of
quantum phase transitions is described in detail. The breakdown of the latter
is analyzed in several examples. In the final part experimental data on
heavy-fermion materials and transition-metal alloys are reviewed and confronted
with existing theory.Comment: 62 pages, 29 figs, review article for Rev. Mod. Phys; (v2) discussion
extended, refs added; (v3) shortened; final version as publishe
Oxidation of mercury by bromine in the subtropical Pacific free troposphere
Mercury is a global toxin that can be introduced to ecosystems through atmospheric deposition. Mercury oxidation is thought to occur in the free troposphere by bromine radicals, but direct observational evidence for this process is currently unavailable. During the 2013 Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks campaign, we measured enhanced oxidized mercury and bromine monoxide in a free tropospheric air mass over Texas. We use trace gas measurements, air mass back trajectories, and a chemical box model to confirm the origin and chemical history of the sampled air mass. We find the presence of elevated oxidized mercury to be consistent with oxidation of elemental mercury by bromine atoms in this subsiding upper tropospheric air mass within the subtropical Pacific High, where dry atmospheric conditions are conducive to oxidized mercury accumulation. Our results support the role of bromine as the dominant oxidant of mercury in the upper troposphereNational Science Foundation (U.S.) (Grants 121701 and, 1215712
Evidence of Simultaneous Circulation of West Nile and Usutu Viruses in Mosquitoes Sampled in Emilia-Romagna Region (Italy) in 2009
BACKGROUND: In recent years human diseases due to mosquito-borne viruses were increasingly reported in Emilia-Romagna region (Italy), from the chikungunya virus in 2007 to the West Nile virus (WNV) in 2008. An extensive entomological survey was performed in 2009 to establish the presence and distribution of mosquito arboviruses in this region, with particular reference to flaviviruses. METHODOLOGY/PRINCIPAL FINDINGS: From May 6 to October 31, a total of 190,516 mosquitoes were sampled in georeferenced stations, grouped in 1,789 pools according date of collection, location, and species, and analyzed by reverse transcription polymerase chain reaction (RT-PCR) to detect the presence of RNA belong to Flavivirus genus. WNV was detected in 27 mosquito pools, producing sequences similar to those of birds and human strains obtained in 2008 outbreak, pointed out the probable virus overwintering. Isolation of WNV was achieved from one of these pools. Moreover 56 pools of mosquitoes tested positive for Usutu virus (USUV). Most PCR positive pools consisted of Culex pipiens, which also was the most analyzed mosquito species (81.4% of specimens); interestingly, USUV RNA was also found in two Aedes albopictus mosquito pools. Simultaneous circulation of WNV and USUV in the survey area was highlighted by occurrence of 8 mosquito WNV- and USUV-positive pools and by the overlaying of the viruses "hot spots", obtained by kernel density estimation (KDE) analysis. Land use of sampled stations pointed out a higher proportion of WNV-positive Cx. pipiens pool in rural environments respect the provenience of total sampled pool, while the USUV-positive pools were uniformly captured in the different environments. CONCLUSIONS/SIGNIFICANCE: Obtained data highlighting the possible role of Cx. pipiens mosquito as the main vector for WNV and USUV in Northern Italy, and the possible involvement of Ae. albopictus mosquito in USUV cycle. The described mosquito-based surveillance could constitute the foundation for a public health alert system targeting mosquito borne arboviruses
Borderline Personality Disorder Symptoms in College Students: The Complex Interplay between Alexithymia, Emotional Dysregulation and Rumination.
Both Emotional Cascade Theory and Linehan's Biosocial Theory suggest dysregulated behaviors associated with Borderline Personality Disorder (BPD) emerge, in part, because of cycles of rumination, poor emotional recognition and poor emotion regulation. In this study we examined relationships between rumination, alexithymia, and emotion regulation in predicting dysregulated behaviors associated with BPD (e.g. self-harm, substance use, aggression), and explored both indirect and moderating effects among these variables. The sample comprised 2261 college students who completed self-report measures of the aforementioned constructs. BPD symptoms, stress, family psychological illness, and alexithymia exerted direct effects on behaviors. Symptoms had an indirect effect on behaviors through rumination, alexithymia and emotional dysregulation. In addition, the relationship between symptoms and dysregulated behaviors was conditional on level of rumination and alexithymia. Implications for early identification and treatment of BPD and related behaviors in college settings are discussed
Bifidobacterium bifidum Actively Changes the Gene Expression Profile Induced by Lactobacillus acidophilus in Murine Dendritic Cells
Dendritic cells (DC) play a pivotal regulatory role in activation of both the innate as well as the adaptive immune system by responding to environmental microorganisms. We have previously shown that Lactobacillus acidophilus induces a strong production of the pro-inflammatory and Th1 polarizing cytokine IL-12 in DC, whereas bifidobacteria do not induce IL-12 but inhibit the IL-12 production induced by lactobacilli. In the present study, genome-wide microarrays were used to investigate the gene expression pattern of murine DC stimulated with Lactobacillus acidophilus NCFM and Bifidobacterium bifidum Z9. L. acidophilus NCFM strongly induced expression of interferon (IFN)-β, other virus defence genes, and cytokine and chemokine genes related to the innate and the adaptive immune response. By contrast, B. bifidum Z9 up-regulated genes encoding cytokines and chemokines related to the innate immune response. Moreover, B. bifidum Z9 inhibited the expression of the Th1-promoting genes induced by L. acidophilus NCFM and had an additive effect on genes of the innate immune response and Th2 skewing genes. The gene encoding Jun dimerization protein 2 (JDP2), a transcription factor regulating the activation of JNK, was one of the few genes only induced by B. bifidum Z9. Neutralization of IFN-β abrogated L. acidophilus NCFM-induced expression of Th1-skewing genes, and blocking of the JNK pathway completely inhibited the expression of IFN-β. Our results indicate that B. bifidum Z9 actively inhibits the expression of genes related to the adaptive immune system in murine dendritic cells and that JPD2 via blocking of IFN-β plays a central role in this regulatory mechanism
DNase Sda1 Allows Invasive M1T1 Group A Streptococcus to Prevent TLR9-Dependent Recognition
Group A Streptococcus (GAS) has developed a broad arsenal of virulence factors that serve to circumvent host defense mechanisms. The virulence factor DNase Sda1 of the hyperinvasive M1T1 GAS clone degrades DNA-based neutrophil extracellular traps allowing GAS to escape extracellular killing. TLR9 is activated by unmethylated CpG-rich bacterial DNA and enhances innate immune resistance. We hypothesized that Sda1 degradation of bacterial DNA could alter TLR9-mediated recognition of GAS by host innate immune cells. We tested this hypothesis using a dual approach: loss and gain of function of DNase in isogenic GAS strains and presence and absence of TLR9 in the host. Either DNA degradation by Sda1 or host deficiency of TLR9 prevented GAS induced IFN-α and TNF-α secretion from murine macrophages and contributed to bacterial survival. Similarly, in a murine necrotizing fasciitis model, IFN-α and TNF-α levels were significantly decreased in wild type mice infected with GAS expressing Sda1, whereas no such Sda1-dependent effect was seen in a TLR9-deficient background. Thus GAS Sda1 suppressed both the TLR9-mediated innate immune response and macrophage bactericidal activity. Our results demonstrate a novel mechanism of bacterial innate immune evasion based on autodegradation of CpG-rich DNA by a bacterial DNase
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