^{7}Be(n,p)^{7}Li Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n_TOF at CERN

We report on the measurement of the ^{7}Be(n,p)^{7}Li cross section from thermal to approximately 325 keV neutron energy, performed in the high-flux experimental area (EAR2) of the n_TOF facility at CERN. This reaction plays a key role in the lithium yield of the big bang nucleosynthesis (BBN) for standard cosmology. The only two previous time-of-flight measurements performed on this reaction did not cover the energy window of interest for BBN, and they showed a large discrepancy between each other. The measurement was performed with a Si telescope and a high-purity sample produced by implantation of a ^{7}Be ion beam at the ISOLDE facility at CERN. While a significantly higher cross section is found at low energy, relative to current evaluations, in the region of BBN interest, the present results are consistent with the values inferred from the time-reversal ^{7}Li(p,n)^{7}Be reaction, thus yielding only a relatively minor improvement on the so-called cosmological lithium problem. The relevance of these results on the near-threshold neutron production in the p+^{7}Li reaction is also discussed.

^{7}Be(n,α)^{4}He Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n_TOF at CERN

The energy-dependent cross section of the ^{7}Be(n,α)^{4}He reaction, of interest for the so-called cosmological lithium problem in big bang nucleosynthesis, has been measured for the first time from 10 meV to 10 keV neutron energy. The challenges posed by the short half-life of ^{7}Be and by the low reaction cross section have been overcome at n_TOF thanks to an unprecedented combination of the extremely high luminosity and good resolution of the neutron beam in the new experimental area (EAR2) of the n_TOF facility at CERN, the availability of a sufficient amount of chemically pure ^{7}Be, and a specifically designed experimental setup. Coincidences between the two alpha particles have been recorded in two Si-^{7}Be-Si arrays placed directly in the neutron beam. The present results are consistent, at thermal neutron energy, with the only previous measurement performed in the 1960s at a nuclear reactor. The energy dependence reported here clearly indicates the inadequacy of the cross section estimates currently used in BBN calculations. Although new measurements at higher neutron energy may still be needed, the n_TOF results hint at a minor role of this reaction in BBN, leaving the long-standing cosmological lithium problem unsolved.

Rosette-forming glioneuronal tumor -- evidence of stem cell origin with biphenotypic differentiation

Rosette-forming glioneuronal tumor (RGNT) of the fourth ventricle is a new addition to the WHO classification of central nervous system tumors. To date, 72 cases have been described in literature. In the present study, we report the clinical and imaging features, with detailed histopathological and immunohistochemical profile, of eight cases. Confocal microscopic evidence of stem cell origin with biphenotypic, glial and neurocytic differentiation is presented with a comprehensive review of literature.

Advances in volume monitoring in dialysis patients

Estimating volume status in patients on chronic dialysis is of great clinical value. Both hypervolemia and hypovolemia are associated with serious short term and long term complications, and volume status is often difficult to assess due to multiple factors affecting intravascular and extravascular volume compartments, as well as variability between patients in baseline blood pressures and physical exams. Traditional methods such as estimated dry weight (EDW) and physical exams are often not accurate because of the subjective nature of these indicators and variability between patients' baselines. This can lead to inaccurate volume status estimation and the associated complications. Furthermore, the concept of estimated dry weight is often defined based on measurements of blood pressure which may not accurately reflect volume status. In this review we describe several methods of measuring volume status in dialysis patients that may be more accurate than traditional measurements of blood pressure and dry weight estimation. These methods include dilutional techniques, imaging of vascular structures, use of biomarkers, bioimpedance analysis and online monitoring of biochemical variables during dialysis itself. We also discuss the clinical applicability and comparisons between these methods including the benefits and drawbacks of these methods and areas for future research.

Blastomycosis in a South Indian patient after visiting an endemic area in USA

We describe a case of blastomycosis in a diabetic patient from South India who had visited Milwaukee, Wisconsin, an endemic area for blastomycosis in the USA. After his return to Bangalore, India, the patient developed intermittent fever of moderate to high grade, cough, loss of weight and appetite, and abscesses in the left cubital fossa and thigh regions. Systemic examination at our hospital revealed that he had dullness to percussion over the chest region and decreased breath sounds. Direct examination of Gram-stained smears of the pus from an abscess showed many broad-based budding yeast cells and culture yielded a dimorphic fungus later identified as Blastomyces dermatitidis. Histologic examination of the curettage tissue slides stained with hematoxylin and eosin, periodic acid Schiff's reagent, and Gomori's methenamine silver stain procedures showed many broad-based budding cells characteristic of B. dermatitidis. The patient was successfully treated, initially with amphotericin B, followed by oral itraconazole for a period of 6 months. Blastomycosis cases in India are reviewed and the likely source of infection in this patient is discussed.

Cytodiagnosis of primary neuritic leprosy

The diagnosis of primary neuritic leprosy (PNL) and its differentiation from other causes of peripheral neuropathy is difficult since acid-fast bacilli (AFB) smears and skin biopsy are negative from anesthetic areas. A biopsy of the involved nerve is the only conclusive method of diagnosis. Such a biopsy may not necessarily be free of complications when a large nerve is involved. However, fine needle aspiration has in this study proved to be a simple technique to demonstrate inflammation granulomas and AFB from these involved nerves in 18 of the 27 cases suspected to have PNL. The validity of the cytological classification into morphological subtypes may have to be supplemented by a large series of studies.

Hepatic mesothelioma

We report a 70-year-old woman with mesothelioma in the liver. The tumor was excised, and the patient is well two years later. Light microscopy of the tumor showed papillary and tubular pattern, in addition to areas of densely packed cells arranged in fascicles. These features and the results of histochemistry and immunohistochemistry indicate a probable histogenesis from submesothelial connective tissue.

Diagnostic value of qualitative and quantitative variables in thyroid lesions

Two hundred and thirty-three thyroid lesions were studied by fine needle aspiration (FNA) cytology using standard cytologic criteria available in the literature. These included 114 cases of nodular colloid goitre (NCG), 47 cases of Hashimoto's thyroiditis (HT), 12 follicular adenomas (FAd), five cases of subacute thyroiditis and three cases of thyrotoxicosis among the benign lesions. The malignant lesions seen were 30 cases of papillary carcinoma (PCa), 16 follicular carcinomas (FCa), three cases with double lesions, e.g. papillary carcinoma with coexisting NCG, and three of papillary carcinoma with HT. Emphasis was given to eight qualitative and quantitative (morphometric) variables in these various thyroid lesions. Cell measurements were done using a Visopan Lux projection microscope. The three qualitative variables included type of nuclear membrane (regular/irregular), type of nuclear chromatin and the presence or absence of conspicuous nucleoli. The quantitative variables studied were nuclear diameter, nuclear area, cytoplasmic diameter, cytoplasmic area & N/C ratio. Statistical analysis was performed in order to know whether the standard cytologic criteria used at FNA cytology in the literature (increased cellularity, microfollicles, increased N/C ratio, absence of significant haemosiderin-laden macrophages and scanty colloid) could differentiate a follicular adenoma from a follicular carcinoma. A statistical analysis was also performed to establish the utility of the qualitative and quantitative variables. The results showed that none of the standard cytologic criteria applied could differentiate follicular adenoma from a follicular carcinoma. With regard to qualitative variables, irregularity of nuclear membrane and presence of conspicuous nucleoli were most significant in papillary carcinoma, followed by follicular carcinoma, then by follicular adenoma; these features being hardly evident in nodular colloid goitre and Hashimoto's thyroiditis. A coarse nuclear chromatin was most significant in follicular carcinomas followed by follicular adenomas. It was less obvious in the benign conditions, but more prominent in Hashimoto's thyroiditis compared with a goitre. It was also not obvious in a papillary carcinoma. Of the quantitative variables, all measurements were greatest in PCa > FCa > FAd > NCG = HT. When differentiating follicular adenoma from follicular carcinoma the qualitative variables of significance were the presence or absence of nucleoli, the chromatin pattern and regularity/irregularity of nuclear membrane; the nuclear area was the most important feature among quantitative variables.