On the spectrum of a bent chain graph

We study Schr\"odinger operators on an infinite quantum graph of a chain form which consists of identical rings connected at the touching points by $\delta$-couplings with a parameter $\alpha\in\R$. If the graph is "straight", i.e. periodic with respect to ring shifts, its Hamiltonian has a band spectrum with all the gaps open whenever $\alpha\ne 0$. We consider a "bending" deformation of the chain consisting of changing one position at a single ring and show that it gives rise to eigenvalues in the open spectral gaps. We analyze dependence of these eigenvalues on the coupling $\alpha$ and the "bending angle" as well as resonances of the system coming from the bending. We also discuss the behaviour of the eigenvalues and resonances at the edges of the spectral bands.Comment: LaTeX, 23 pages with 7 figures; minor changes, references added; to appear in J. Phys. A: Math. Theo

Anthropology, Brokerage and Collaboration in the development of a Tongan Public Psychiatry: Local Lessons for Global Mental Health

The Global Mental Health (GMH) movement has revitalised questions of the translatability of psychiatric concepts and the challenges of community engagement in countries where knowledge of the biomedical basis for psychiatric diagnosis is limited or challenged by local cultural codes. In Tonga, the local psychiatrist Dr Puloka has successfully established a publicly accessible psychiatry that has raised admission rates for serious mental illness and addressed some of the stigma attached to diagnosis. On the basis of historical analysis and ethnographic fieldwork with healers, doctors and patients since 1998, this article offers an ethnographic contextualization of the development and reception of three key interventions during the 1990s inspired by traditional healing and reliant on the translation of psychiatric terms and diagnosis. Dr Puloka’s use of medical anthropological and transcultural psychiatry research informed a community engaged brokerage between the implications of psychiatric nosologies and local needs. As such it reveals deficiencies in current polarised positions on the GMH project and offers suggestions to address current challenges of the Global Mental Health movement

MOBP-specific cellular immune responses are weaker than MOG-specific cellular immune responses in patients with multiple sclerosis and healthy subjects.

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system (CNS). Myelin oligodendrocyte glycoprotein (MOG) and myelin oligodendrocyte basic protein (MOBP) were both shown to be highly encephalitogenic in animal models of MS. In contrast, the association of MOG- and MOBP-specific humoral or cellular immune responses and MS in humans is far less established. In this study, we sought to analyse MOG- and MOBP-specific T-cell responses in a large cohort of patients with various stages of the disease. Patients with other neurological diseases and healthy subjects were enrolled to serve as control study subjects. We determined the proliferation and the secretion of IFN-γ secretion in our cohort. We found that MOG-specific T-cell responses were higher and more frequent as compared to MOBP-specific ones. However, both MS patients and control study subjects had similar myelin-specific T-cell responses at the periphery, thus calling for more precise studies at CNS level

Public Protests and the Risk of Novel Coronavirus Disease Hospitalizations: A County-Level Analysis from California

The objective of this study was to assess the relationship between public protests and county-level, novel coronavirus disease (COVID-19) hospitalization rates across California. Publicly available data were included in the analysis from 55 of 58 California state counties (29 March–14 October 2020). Mixed-effects negative binomial regression models were used to examine the relationship between daily county-level COVID-19 hospitalizations and two main exposure variables: any vs. no protests and 1 or \u3e1 protest vs. no protests on a given county-day. COVID-19 hospitalizations were used as a proxy for viral transmission since such rates are less sensitive to temporal changes in testing access/availability. Models included covariates for daily county mobility, county-level characteristics, and time trends. Models also included a county-population offset and a two-week lag for the association between exposure and outcome. No significant associations were observed between protest exposures and COVID-19 hospitalization rates among the 55 counties. We did not find evidence to suggest that public protests were associated with COVID-19 hospitalization within California counties. These findings support the notion that protesting during a pandemic may be safe, ostensibly, so long as evidence-based precautionary measures are taken

MRI Findings in People with Epilepsy and Nodding Syndrome in an Area Endemic for Onchocerciasis: An Observational Study.

Onchocerciasis has been implicated in the pathogenesis of epilepsy. The debate on a potential causal relationship between Onchocerca volvulus and epilepsy has taken a new direction in the light of the most recent epidemic of nodding syndrome. To document MRI changes in people with different types of epilepsy and investigate whether there is an association with O. volvulus infection. In a prospective study in southern Tanzania, an area endemic for O. volvulus with a high prevalence of epilepsy and nodding syndrome, we performed MRI on 32 people with epilepsy, 12 of which suffered from nodding syndrome. Polymerase chain reaction (PCR) of O. volvulus was performed in skin and CSF. The most frequent abnormalities seen on MRI was atrophy (twelve patients (37.5%)) followed by intraparenchymal pathologies such as changes in the hippocampus (nine patients (28.1%)), gliotic lesions (six patients (18.8%)) and subcortical signal abnormalities (three patients (9.4%)). There was an overall trend towards an association of intraparenchymal cerebral pathologies and infection with O. volvulus based on skin PCR (Fisher's Exact Test p=0.067) which was most pronounced in children and adolescents with nodding syndrome compared to those with other types of epilepsy (Fisher's Exact Test, p=0.083). Contrary to skin PCR results, PCR of CSF was negative in all patients. The observed trend towards an association of intraparenchymal cerebral pathological results on MRI and a positive skin PCR for O. volvulus despite negative PCR of CSF is intriguing and deserves further attention

Immunohistochemical localization of fibronectin as a tool for the age determination of human skin wounds

We analyzed the distribution of fibronectin in routinely embedded tissue specimens from 53 skin wounds and 6 postmortem wounds. In postmortem wounds a faint but focal positive staining was exclusively found at the margin of the specimens which dit not extend into the adjacent stroma. Vital wounds were classified into 3 groups. The first comprising lesions with wound ages ranging from a few seconds to 30 min, the second comprising those with wound ages upt to 3 weeks, and the third group with lesions more than 3 weeks old. Ten out of 17 lesions with a wound age up to 30 min showed a clear positive reaction within the wound area. Three specimens in this group were completely negative, while in 4 additional cases the result was not significantly different from postmortem lesions. These 7 cases were characterized by acute death with extremely short survival times (only seconds). In wounds up to 3 weeks old fibronectin formed a distinct network containing an increasing number of inflammatory cells corresponding to the wound age. In 2 cases with a survival time of 17 days and in all wounds older than 3 weeks fibronectin was restricted to the surface of fibroblasts and to parallel arranged fibers in the granulation tissue without any network structures. We present evidence that fibronectin is a useful marker for vital wounds with a survival time of more than a few minutes. Fibronectin appears before neutrophilic granulocytes migrate into the wound area. Since a faint positive fibronectin staining is seen in postmortem lesions and bleedings, we propose that only those wounds which show strong positive fibronectin staining also extending into the adjacent stroma should be regarded as vital

Substrate specificity of a peptidyl-aminoacyl-l/d-isomerase from frog skin

In the skin of fire-bellied toads (Bombina species), an aminoacyl-l/d-isomerase activity is present which catalyses the post-translational isomerization of the l- to the d-form of the second residue of its substrate peptides. Previously, this new type of enzyme was studied in some detail and genes potentially coding for similar polypeptides were found to exist in several vertebrate species including man. Here, we present our studies to the substrate specificity of this isomerase using fluorescence-labeled variants of the natural substrate bombinin H with different amino acids at positions 1, 2 or 3. Surprisingly, this enzyme has a rather low selectivity for residues at position 2 where the change of chirality at the alpha-carbon takes place. In contrast, a hydrophobic amino acid at position 1 and a small one at position 3 of the substrate are essential. Interestingly, some peptides containing a Phe at position 3 also were substrates. Furthermore, we investigated the role of the amino-terminus for substrate recognition. In view of the rather broad specificity of the frog isomerase, we made a databank search for potential substrates of such an enzyme. Indeed, numerous peptides of amphibia and mammals were found which fulfill the requirements determined in this study. Expression of isomerases with similar characteristics in other species can therefore be expected to catalyze the formation of peptides containing d-amino acids

Influence of organic versus inorganic dietary selenium supplementation on the concentration of selenium in colostrum, milk and blood of beef cows

<p>Abstract</p> <p>Background</p> <p>Selenium (Se) is important for the postnatal development of the calf. In the first weeks of life, milk is the only source of Se for the calf and insufficient level of Se in the milk may lead to Se deficiency. Maternal Se supplementation is used to prevent this.</p> <p>We investigated the effect of dietary Se-enriched yeast (SY) or sodium selenite (SS) supplements on selected blood parameters and on Se concentrations in the blood, colostrum, and milk of Se-deficient Charolais cows.</p> <p>Methods</p> <p>Cows in late pregnancy received a mineral premix with Se (SS or SY, 50 mg Se per kg premix) or without Se (control – C). Supplementation was initiated 6 weeks before expected calving. Blood and colostrum samples were taken from the cows that had just calved (Colostral period). Additional samples were taken around 2 weeks (milk) and 5 weeks (milk and blood) after calving corresponding to Se supplementation for 6 and 12 weeks, respectively (Lactation period) for Se, biochemical and haematological analyses.</p> <p>Results</p> <p>Colostral period. Se concentrations in whole blood and colostrum on day 1 <it>post partum </it>and in colostrum on day 3 <it>post partum </it>were 93.0, 72.9, and 47.5 μg/L in the SY group; 68.0, 56.0 and 18.8 μg/L in the SS group; and 35.1, 27.3 and 10.5 μg/L in the C group, respectively. Differences among all the groups were significant (<it>P </it>< 0.01) at each sampling, just as the colostrum Se content decreases were from day 1 to day 3 in each group. The relatively smallest decrease in colostrum Se concentration was found in the SY group (<it>P </it>< 0.01).</p> <p>Lactation period. The mean Se concentrations in milk in weeks 6 and 12 of supplementation were 20.4 and 19.6 μg/L in the SY group, 8.3 and 11.9 μg/L in the SS group, and 6.9 and 6.6 μg/L in the C group, respectively. The values only differed significantly in the SS group (<it>P </it>< 0.05). The Se concentrations in the blood were similar to those of cows examined on the day of calving. The levels of glutathione peroxidase (GSH-Px) activity were 364.70, 283.82 and 187.46 μkat/L in the SY, SS, and C groups, respectively. This was the only significantly variable biochemical and haematological parameter.</p> <p>Conclusion</p> <p>Se-enriched yeast was much more effective than sodium selenite in increasing the concentration of Se in the blood, colostrum and milk, as well as the GSH-Px activity.</p

Decreased CD8+ T cell response to Epstein-Barr virus infected B cells in multiple sclerosis is not due to decreased HLA class I expression on B cells or monocytes

Background: Patients with multiple sclerosis (MS) have a decreased frequency of CD8(+) T cells reactive to their own Epstein-Barr virus (EBV) infected B cells. We have proposed that this might predispose to the development of MS by allowing EBV-infected autoreactive B cells to accumulate in the central nervous system. The decreased CD8(+) T cell response to EBV results from a general CD8(+) T cell deficiency and also a decreased proportion of EBV-specific T cells within the total CD8(+) T cell population. Because decreased HLA class I expression on monocytes and B cells has been reported in MS and could influence the generation and effector function of EBV-specific CD8(+) T cells, the present study was undertaken to measure the expression of HLA molecules on B cells and monocytes in patients with MS

Pre-Existing T- and B-Cell Defects in One Progressive Multifocal Leukoencephalopathy Patient

Progressive multifocal leukoencephalopathy (PML) usually occurs in patients with severe immunosuppression, hematological malignancies, chronic inflammatory conditions or receiving organ transplant. Recently, PML has also been observed in patients treated with monoclonal antibodies. By taking advantage of the availability of samples from a multiple sclerosis (MS) patient treated with natalizumab, the antibody anti-α4 integrin, who developed PML and was monitored starting before therapy initiation, we investigated the fate of T and B lymphocytes in the onset of PML. Real-time PCR was used to measure new T- and B-cell production by means of T-cell receptor excision circle (TREC) and K-deleting recombination excision circle (KREC) analysis and to quantify transcripts for CD34, terminal-deoxynucleotidyltransferase, and V pre-B lymphocyte gene 1. T- and B-cell subsets and T-cell heterogeneity were measured by flow cytometry and spectratyping. The data were compared to those of untreated and natalizumab-treated MS patients and healthy donors. Before therapy, a patient who developed PML had a low TREC and KREC number; TRECs remained low, while KRECs and pre-B lymphocyte gene 1 transcripts peaked at 6 months of therapy and then decreased at PML diagnosis. Flow cytometry confirmed the deficient number of newly produced T lymphocytes, counterbalanced by an increase in TEMRA cells. The percentage of naive B cells increased by approximately 70% after 6 months of therapy, but B lymphocyte number remained low for the entire treatment period. T-cell heterogeneity and immunoglobulins were reduced