724 research outputs found
Darstellung neuartiger Carbosilan- und Polyether-Glycodendrimere
In the course of this thesis, novel carbosilane and polyether glycodendrimers were prepared. These structures are potential inhibitors of mannose binding lectins of E. coli. Further, the access to these glycodendrimers was evaluated in view of synthetic chemistry. A tetravalent carbosiloxane glycodendrimer was prepared via alcoholysis of a chlorosilane with a hydroxyethyl glycoside, the corresponding tetravalent carbosilane derivative was synthesised via hydrosilylation of an allyl glycoside with a hydrosilane. Polyether glycodendrimers with a glycerol scaffold were prepared via a reaction sequence containing Williamson etherification with 3-chloro-2-chloro-methyl-1-propene followed by trans-formation of the double bond at the focal point of the molecule via a ozonolysis-reduction protocol to a secondary alcohol. By introduction of glycol ether spacers between glycerol units more spacious glycerol glycol ethers could be obtained. For both types tetravalent glycodendrimers could be prepared in good yields and syntheses were carried out on a multigramm scale, while the octavalent compounds were obtained only in low yields
A prospective multicentre study in Sweden and Norway of mental distress and psychiatric morbidity in head and neck cancer patients
A Swedish/Norwegian head and neck cancer study was designed to assess prospectively the levels of mental distress and psychiatric morbidity in a heterogeneous sample of newly diagnosed head and neck cancer patients. A total of 357 patients were included. The mean age was 63 years, and 72% were males. The patients were asked to answer the HAD scale (the Hospital Anxiety and Depression scale) six times during 1 year. The number of possible or probable cases of anxiety or depression disorder was calculated according to standardized cut-offs. Approximately one-third of the patients scored as a possible or probable case of a major mood disorder at each measurement point during the study year. There were new cases of anxiety or depression at each time point. The anxiety level was highest at diagnosis, while depression was most common during treatment. Females were more anxious than males at diagnosis, and patients under 65 years of age scored higher than those over 65. Patients with lower performance status and more advanced disease reported higher levels of mental distress and more often scored as a probable or possible cases of psychiatric disorder. Our psychometric analyses supported the two-dimensional structure and stability of the HAD scale. The HAD scale seems to be the method of choice for getting valid information about the probability of mood disorder in head and neck cancer populations. The prevalence of psychiatric morbidity found in this study emphasizes the importance of improved diagnosis and treatment
Bovine CD2(-)/NKp46(+ )cells are fully functional natural killer cells with a high activation status
BACKGROUND: Natural killer (NK) cells in the cow have been elusive due to the lack of specific NK cell markers, and various criteria including a CD3(-)/CD2(+ )phenotype have been used to identify such cells. The recent characterization of the NK-specific NKp46 receptor has allowed a more precise definition of bovine NK cells. NK cells are known as a heterogeneous cell group, and we here report the first functional study of bovine NK cell subsets, based on the expression of CD2. RESULTS: Bovine CD2(- )NK cells, a minor subset in blood, proliferated more rapidly in the presence of IL-2, dominating the cultures after a few days. Grown separately with IL-2, CD2(- )and CD2(+ )NK cell subsets did not change CD2 expression for at least two weeks. In blood, CD2(- )NK cells showed a higher expression of CD44 and CD25, consistent with a high activation status. A higher proportion of CD2(- )NK cells had intracellular interferon-gamma in the cytoplasm in response to IL-2 and IL-12 stimulation, and the CD2(- )subset secreted more interferon-gamma when cultured separately. Cytotoxic capacity was similar in both subsets, and both carried transcripts for the NK cell receptors KIR, CD16, CD94 and KLRJ. Ligation by one out of two tested anti-CD2 monoclonal antibodies could trigger interferon-gamma production from NK cells, but neither of them could alter cytotoxicity. CONCLUSION: These results provide evidence that bovine CD2(- )as well as CD2(+ )cells of the NKp46(+ )phenotype are fully functional NK cells, the CD2(- )subset showing signs of being more activated in the circulation
Mycotoxins and Other Secondary Metabolites Produced in vitro by Penicillium paneum Frisvad and Penicillium roqueforti Thom Isolated from Baled Grass Silage in Ireland
Effects of the COVID-19 pandemic on medical students: a multicenter quantitative study
© 2021, The Author(s). Background: The COVID-19 pandemic disrupted the United States (US) medical education system with the necessary, yet unprecedented Association of American Medical Colleges (AAMC) national recommendation to pause all student clinical rotations with in-person patient care. This study is a quantitative analysis investigating the educational and psychological effects of the pandemic on US medical students and their reactions to the AAMC recommendation in order to inform medical education policy. Methods: The authors sent a cross-sectional survey via email to medical students in their clinical training years at six medical schools during the initial peak phase of the COVID-19 pandemic. Survey questions aimed to evaluate students’ perceptions of COVID-19’s impact on medical education; ethical obligations during a pandemic; infection risk; anxiety and burnout; willingness and needed preparations to return to clinical rotations. Results: Seven hundred forty-one (29.5%) students responded. Nearly all students (93.7%) were not involved in clinical rotations with in-person patient contact at the time the study was conducted. Reactions to being removed were mixed, with 75.8% feeling this was appropriate, 34.7% guilty, 33.5% disappointed, and 27.0% relieved. Most students (74.7%) agreed the pandemic had significantly disrupted their medical education, and believed they should continue with normal clinical rotations during this pandemic (61.3%). When asked if they would accept the risk of infection with COVID-19 if they returned to the clinical setting, 83.4% agreed. Students reported the pandemic had moderate effects on their stress and anxiety levels with 84.1% of respondents feeling at least somewhat anxious. Adequate personal protective equipment (PPE) (53.5%) was the most important factor to feel safe returning to clinical rotations, followed by adequate testing for infection (19.3%) and antibody testing (16.2%). Conclusions: The COVID-19 pandemic disrupted the education of US medical students in their clinical training years. The majority of students wanted to return to clinical rotations and were willing to accept the risk of COVID-19 infection. Students were most concerned with having enough PPE if allowed to return to clinical activities
Condensation of a tetrahedra rigid-body libration mode in HoBaCo4O7 : the origin of phase transition at 355 K
Rietveld profiles, Moessbauer spectra and x-ray absorption fine structure
(XAFS) were analyzed through the structural phase transition at Ts = 355 K in
HoBaCo4O7. Excess of the oxygen content over O7 was avoided via annealing the
samples in argon flow at 600 degree C. Space groups (S.G.) Pbn21c and P63mc
were used to refine the structure parameters in the low- and high-temperature
phases, respectively. Additionally, the Cmc21 symmetry was considered as a
concurrent model of structure of the low-temperature phase. In the
high-temperature phase, severe anisotropy of thermal motion of the major part
of the oxygen atoms was observed. This anisotropic motion turns to be quenched
as the sample is cooled below Ts. The variation of quadrupole splitting near Ts
is not similar to a steplike anomaly frequently seen at the charge-ordering
transition. We observe instead a dip-like anomaly of the average quadrupole
splitting near Ts. Narrow distribution of the electric field gradient (EFG)
over different cobalt sites is observed and explained on the basis of
point-charge model. XAFS spectra show no evidence of significant difference
between YBaCo4O7 (T > Ts) and HoBaCo4O7 (T < Ts). The origin of the transition
at Ts is ascribed to the condensation of the libration phonon mode associated
with the rigid-body rotational movements of the starlike tetrahedral units, the
building blocks of kagome network. It is shown that the condensation of the
libration mode is not compatible with translation symmetry for the hexagonal
S.G., but compatible for the orthorhombic S.G. The orthorhombic lattice
parameters and EFG components (Vxx, Vyy, Vzz) vary smoothly with temperature at
approaching Ts and closely follow each other.Comment: 13 figure
Nucleosomes in serum of patients with early cerebral stroke
Background: Nucleosomes are cell death products that are elevated in serum of patients with diseases that are associated with massive cell destruction. We investigated the kinetics of circulating nucleosomes after cerebral stroke and their correlation with the clinical status. Methods: In total, we analyzed nucleosomes by ELISA in sera of 63 patients with early stroke daily during the first week after onset. For correlation with the clinical pathology, patients were grouped into those with medium to slight functional impairment (Barthel Index BI >= 50) and those with severe functional impairment (BI = 50 showed a continuous increase in nucleosomes until day 5 (median: 523 arbitrary units, AU) followed by a slow decline. In contrast, patients with BI = 50 (497 AU; p = 0.031). Concerning the infarction volume, nucleosomes showed significant correlations for the concentrations on day 3 (r = 0.43; p = 0.001) and for the area under the curve (r = 0.34; p = 0.016). Conclusion: Even if nucleosomes are nonspecific cell death markers, their release into serum after cerebral stroke correlates with the gross functional status as well as with the infarction volume and can be considered as biochemical correlative to the severity of stroke. Copyright (c) 2006 S. Karger AG, Basel
Auditory ERPs to Stimulus Deviance in an Awake Chimpanzee (Pan troglodytes): Towards Hominid Cognitive Neurosciences
BACKGROUND: For decades, the chimpanzee, phylogenetically closest to humans, has been analyzed intensively in comparative cognitive studies. Other than the accumulation of behavioral data, the neural basis for cognitive processing in the chimpanzee remains to be clarified. To increase our knowledge on the evolutionary and neural basis of human cognition, comparative neurophysiological studies exploring endogenous neural activities in the awake state are needed. However, to date, such studies have rarely been reported in non-human hominid species, due to the practical difficulties in conducting non-invasive measurements on awake individuals. METHODOLOGY/PRINCIPAL FINDINGS: We measured auditory event-related potentials (ERPs) of a fully awake chimpanzee, with reference to a well-documented component of human studies, namely mismatch negativity (MMN). In response to infrequent, deviant tones that were delivered in a uniform sound stream, a comparable ERP component could be detected as negative deflections in early latencies. CONCLUSIONS/SIGNIFICANCE: The present study reports the MMN-like component in a chimpanzee for the first time. In human studies, various ERP components, including MMN, are well-documented indicators of cognitive and neural processing. The results of the present study validate the use of non-invasive ERP measurements for studies on cognitive and neural processing in chimpanzees, and open the way for future studies comparing endogenous neural activities between humans and chimpanzees. This signifies an essential step in hominid cognitive neurosciences
A blind detection of a large, complex, Sunyaev--Zel'dovich structure
We present an interesting Sunyaev-Zel'dovich (SZ) detection in the first of
the Arcminute Microkelvin Imager (AMI) 'blind', degree-square fields to have
been observed down to our target sensitivity of 100{\mu}Jy/beam. In follow-up
deep pointed observations the SZ effect is detected with a maximum peak
decrement greater than 8 \times the thermal noise. No corresponding emission is
visible in the ROSAT all-sky X-ray survey and no cluster is evident in the
Palomar all-sky optical survey. Compared with existing SZ images of distant
clusters, the extent is large (\approx 10') and complex; our analysis favours a
model containing two clusters rather than a single cluster. Our Bayesian
analysis is currently limited to modelling each cluster with an ellipsoidal or
spherical beta-model, which do not do justice to this decrement. Fitting an
ellipsoid to the deeper candidate we find the following. (a) Assuming that the
Evrard et al. (2002) approximation to Press & Schechter (1974) correctly gives
the number density of clusters as a function of mass and redshift, then, in the
search area, the formal Bayesian probability ratio of the AMI detection of this
cluster is 7.9 \times 10^4:1; alternatively assuming Jenkins et al. (2001) as
the true prior, the formal Bayesian probability ratio of detection is 2.1
\times 10^5:1. (b) The cluster mass is MT,200 = 5.5+1.2\times 10^14h-1M\odot.
(c) Abandoning a physical model with num- -1.3 70 ber density prior and instead
simply modelling the SZ decrement using a phenomenological {\beta}-model of
temperature decrement as a function of angular distance, we find a central SZ
temperature decrement of -295+36 {\mu}K - this allows for CMB primary
anisotropies, receiver -15 noise and radio sources. We are unsure if the
cluster system we observe is a merging system or two separate clusters.Comment: accepted MNRAS. 12 pages, 9 figure
"Author! Author!" : Shakespeare and biography
Original article can be found at: http://www.informaworld.com/smpp/title~content=t714579626~db=all Copyright Informa / Taylor & Francis Group. DOI: 10.1080/17450910902764454Since 1996, not a year has passed without the publication of at least one Shakespeare biography. Yet for many years the place of the author in the practice of understanding literary works has been problematized, and even on occasions eliminated. Criticism reads the “works”, and may or may not refer to an author whose “life” contributed to their meaning. Biography seeks the author in the works, the personality that precedes the works and gives them their characteristic shape and meaning. But the form of literary biography addresses the unusual kind of “life” that puts itself into “works”, and this is particularly challenging where the “works” predominate massively over the salient facts of the “life”. This essay surveys the current terrain of Shakespeare biography, and considers the key questions raised by the medium: can we know anything of Shakespeare's “personality” from the facts of his life and the survival of his works? What is the status of the kind of speculation that inevitably plays a part in biographical reconstruction? Are biographers in the end telling us as much about themselves as they tell us about Shakespeare?Peer reviewe
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