Glassy Dynamics in a heavy ion irradiated NbSe2 crystal

Fascination with glassy states has persisted since Fisher introduced the vortex-glass as a new thermodynamic phase that is a true superconductor that lacks conventional long-range order. Though Fisher's original model considered point disorder, it was later predicted that columnar defects (CDs) could also induce glassiness - specifically, a Bose-glass phase. In YBa2Cu3O7-x (YBCO), glassy states can cause distinct behavior in the temperature (T ) dependent rate of thermally activated vortex motion (S). The vortex-glass state produces a plateau in S(T ) whereas a Bose-glass can transition into a state hosting vortex excitations called double-kinks that can expand, creating a large peak in S(T ). Although glass phases have been well-studied in YBCO, few studies exist of other materials containing CDs that could contribute to distinguishing universal behavior. Here, we report on the effectiveness of CDs tilted ~30° from the c-axis in reducing S in a NbSe2 crystal. The magnetization is 5 times higher and S is minimized when the field is parallel to the defects versus aligned with the c-axis. We see signatures of glassiness in both field orientations, but do not observe a peak in S(T ) nor a plateau at values observed in YBCO. Finally, we discuss the possibility that competing disorder induces a field-orientation-driven transition from a Bose-glass to an anisotropic glass involving both point and columnar disorder.

Universal lower limit on vortex creep in superconductors

Superconductors are excellent testbeds for studying vortices, topological excitations that also appear in superfluids, liquid crystals and Bose-Einstein condensates. Vortex motion can be disruptive; it can cause phase transitions, glitches in pulsars, and losses in superconducting microwave circuits, and it limits the current-carrying capacity of superconductors. Understanding vortex dynamics is fundamentally and technologically important, and the competition between thermal energy and energy barriers defined by material disorder is not completely understood. Specifically, early measurements of thermally activated vortex motion (creep) in iron-based superconductors unveiled fast rates (S) comparable to measurements of YBa ₂Cu₃O_7-δ (refs ,,,,,). This was puzzling because S is thought to somehow correlate with the Ginzburg number (Gi), and Gi is significantly lower in most iron-based superconductors than in YBa ₂Cu₃O_7-δ. Here, we report very slow creep in BaFe ₂(As_0.67P_0.33)₂ films, and propose the existence of a universal minimum realizable S ∼ Gi^1/2(T/T_c) (T_c is the superconducting transition temperature) that has been achieved in our films and few other materials, and is violated by none. This limitation provides new clues about designing materials with slow creep and the interplay between material parameters and vortex dynamics.

Quantum Critical Scaling in the Disordered Itinerant Ferromagnet UCo_{1-x}Fe_{x}Ge

The Belitz-Kirkpatrick-Vojta (BKV) theory shows in excellent agreement with experiment that ferromagnetic quantum phase transitions (QPTs) in clean metals are generally first order due to the coupling of the magnetization to electronic soft modes, in contrast to the classical analogue that is an archetypical second-order phase transition. For disordered metals the BKV theory predicts that the second-order nature of the QPT is restored because the electronic soft modes change their nature from ballistic to diffusive. Our low-temperature magnetization study identifies the ferromagnetic QPT in the disordered metal UCo_{1-x}Fe_{x}Ge as the first clear example that exhibits the associated critical exponents predicted by the BKV theory.

Differential Effect of Renal Cortical and Medullary Interstitial Fluid Calcium on Blood Pressure Regulation in Salt-Sensitive Hypertension

BACKGROUND

Hypercalciuria is a frequent characteristic of hypertension. In this report we extend our earlier studies investigating the role of renal interstitial fluid calcium (ISF(Ca))(2+) as a link between urinary calcium excretion and blood pressure in the Dahl salt-sensitive (DS) hypertensive model.

METHODS

Dahl salt-sensitive and salt-resistant (DR) rats were placed on control (0.45%) and high (8%) salt diets to determine if changes in renal cortical and medullary ISF(Ca)(2+)correlated with changes in urinary calcium excretion and blood pressure.

RESULTS

We observed that renal ISFCa(2+) was predicted by urinary calcium excretion (P < 0.05) in DS rats but not DR rats. Renal cortical ISF(Ca)(2+) was negatively associated with blood pressure (P < 0.03) while renal medullary ISF(Ca)(2+) was positively associated with blood pressure in DS rats (P < 0.04). In contrast, neither urinary calcium excretion nor renal ISF(Ca)(2+) was associated with blood pressure in the DR rats under the conditions of this study.

CONCLUSION

We interpret these findings to suggest that decreased renal cortical ISF(Ca)(2+) plays a role in the increase in blood pressure following a high salt diet in salt hypertension perhaps by mediating renal vasoconstriction; the role of medullary calcium remains to be fully understood. Further studies are needed to determine the mechanism of the altered renal ISF(Ca)(2+) and its role in blood pressure regulation.

Particle-size dependent effects in the Balb/c murine model of inhalational melioidosis

Deposition of Burkholderia pseudomallei within either the lungs or nasal passages of the Balb/c murine model resulted in different infection kinetics. The infection resulting from the inhalation of B. pseudomallei within a 12 μm particle aerosol was prolonged compared to a 1 μm particle aerosol with a mean time-to-death (MTD) of 174.7 ± 14.9 h and 73.8 ± 11.3 h, respectively. Inhalation of B. pseudomallei within 1 μm or 12 μm particle aerosols resulted in a median lethal dose (MLD) of 4 and 12 cfu, respectively. The 12 μm particle inhalational infection was characterized by a marked involvement of the nasal mucosa and extension of bacterial colonization and inflammatory lesions from the olfactory epithelium through the olfactory nerves (or tracts) to the olfactory bulb (100%), culminating in abscessation of the brain (33%). Initial involvement of the upper respiratory tract lymphoid tissues (nasal-associated lymphoid tissue (NALT) and cervical lymph nodes) was observed in both the 1 and 12 μm particle inhalational infections (80-85%). Necrotising alveolitis and bronchiolitis were evident in both inhalational infections, however, lung pathology was greater after inhalation of the 1 μm particle aerosol with pronounced involvement of the mediastinal lymph node (50%). Terminal disease was characterized by bacteraemia in both inhalational infections with dissemination to the spleen, liver, kidneys, and thymus. Treatment with co-trimoxazole was more effective than treatment with doxycycline irrespective of the size of the particles inhaled. Doxycycline was more effective against the 12 μm particle inhalational infection as evidenced by increased time to death. However, both treatment regimes exhibited significant relapse when therapy was discontinued with massive enlargement and abscessation of the lungs, spleen, and cervical lymph nodes observed.

Eating habits, beliefs, attitudes and knowledge among health professionals regarding the links between obesity, nutrition and health

Objective:

To document knowledge, attitudes, beliefs and eating habits of health professionals with respect to obesity, nutrition and weight management.

Design:

A self-complete questionnaire postal survey.

Setting:

Primary care and dietetic practice in Scotland.

Subjects:

A systematic stratified sample of 2290 subjects incorporated general practitioners (n = 1400), practice nurses (n = 613) and all practising dietitians (n = 360) who were members of the British Dietetic Association.

Results:

The overall response rate was 65%. All professionals showed a clear understanding of nutrition and health. Understanding of obesity as a disease and of the effectiveness of weight management using low-energy diets was limited. Below 10% had carried out audit to determine the incidence of obesity and overweight, and most were uncertain about their own effectiveness in delivering weight management advice.

Conclusion:

This study confirms that health professionals have some knowledge of nutrition and weight management but are unclear how to deliver effective weight management advice. Further training is justified to ensure the effective provision of nutritional advice to patients.

Identification of a mouse orthologue of the CED-6 gene of Caenorhabditis elegans

The rapid engulfment of apoptotic cells is a specialized innate immune response used by organisms to remove apoptotic cells. In mammals, several receptors that recognize apoptotic cells have been identified. Previous analysis of the engulfment gene ced-6 in Caenorhabditis elegans (C. elegans) has suggested that CED-6 is an adapter protein that participates in signal transduction pathway that mediates the specific recognition and engulfment of apoptotic cells. Here, we describe our isolation and partial characterization of a mouse cDNA, which is like an orthologue of C. elegans CED-6. PCR screening of mouse cDNA pool with primers designed from the C. elegans CED-6 cDNA sequence resulted in about 300 bp PCR product which was partially sequenced and then screened to a mouse full-length cDNA library. Thus in this study we report the identification of a novel C. elegans CED-6-like orthologue in mouse, which has probable apoptotic like function.

Evaluation of a bar-code system for nutrient analysis in dietary surveys

OBJECTIVE

A novel system for nutrient analysis has been developed and tested over 5 years. Its key features are a nutrient database of 600 commonly eaten foods (95% of foods eaten in 7-day surveys); a booklet identifying each food with a bar code, bar codes for gram weight and for portion sizes (small, medium, large) and a bar-code reader with dietary analysis software for PCs. In the present study the bar-code system has been evaluated by comparison with a commonly used manual entry nutrient analysis software for dietitians' use.

DESIGN

Cross-sectional.

SETTING

Glasgow city district.

SUBJECTS

One hundred and sixty adults aged 18-65 years old.

RESULTS

Comparing mean intakes for macro- and micronutrients, using the Bland and Altman method, the bias between the two methods was small, ranging from 0.93 to 1.03. The bar-code system took significantly less professional time in data entry and nutrient analysis than the widely used manual system (29min per 7-day diary vs. 47 min per 7-day diary, P < 0.001).

CONCLUSIONS

It is suggested that the bar-code system offers greater speed with a saving of professional time needed for nutrient analysis of dietary surveys. This system is commended for maintaining accuracy while promoting economy.

Has psychological distress among UK South Asians been under-estimated? A comparison of three measures in the west of Scotland population

OBJECTIVES

Previous work has shown low levels of psychological distress among UK South Asians, but some argue that the distress is under-reported. The present paper assesses distress on one clinically validated measure (the 12-item General Health Questionnaire), a psychosomatic measure and a self-report measure.

METHODS

Interviews of 159 South Asians in Glasgow aged 30-40 years, mean age 35 years and 319 from the general population, all aged 35 years.

RESULTS

The three distress measures were moderately correlated and at the thresholds chosen there was no hierarchy of severity between them. Distress on the GHQ12 was at similar levels for all the social groups assessed, but distress on the psychosomatic measure and self-assessment was higher for women, Muslims and limited English speakers.

CONCLUSIONS

Clinical measures may have under-estimated distress in several South Asian groups. The results may be due to a preference for a particular language of emotion in the affected groups or to a higher frequency of stressful situations which provoke distinctive reactions.

Cell lineage and cell determination in the developing compound eye of the cockroach, Periplaneta americana

By grafting between eye colour mutants of the cockroach Periplaneta americana we have investigated (i) the hypothesis that cells within an ommatidium of the fused rhabdom type are clonally derived from a single mother cell and (ii) we have tested the suggestion that cells from non-prospective eye epidermis can form ommatidia when grafted next to eye tissue. Mosaic eyes containing cells of the two genotypes contain ommatidia with unpredictable combinations of the two sorts of cells at the host/graft border. This finding is inconsistent with the first hypothesis. Using grafts of prothoracic epidermis and head epidermis from non-prospective eye regions we have shown that only cells from the prospective eye region can form ommatidia. Possible ways that eye cells could be determined are discussed in the light of these findings.

Cell lineage and cell determination in the developing compound eye of the cockroach, Periplaneta americana

By grafting between eye colour mutants of the cockroach Periplaneta americana we have investigated (i) the hypothesis that cells within an ommatidium of the fused rhabdom type are clonally derived from a single mother cell and (ii) we have tested the suggestion that cells from non-prospective eye epidermis can form ommatidia when grafted next to eye tissue. Mosaic eyes containing cells of the two genotypes contain ommatidia with unpredictable combinations of the two sorts of cells at the host/graft border. This finding is inconsistent with the first hypothesis. Using grafts of prothoracic epidermis and head epidermis from non-prospective eye regions we have shown that only cells from the prospective eye region can form ommatidia. Possible ways that eye cells could be determined are discussed in the light of these findings.

Cell junctions in the developing compound eye of the desert locust Schistocerca gregaria

Intercellular junctions in the developing retina of the locust Schistocerca gregaria have been examined by electron microscopy. Different types of junction appear in a well defined sequence during development. Five stages of ommatidial development are described. Close junctions and punctate junctions are present throughout development. Gap junctions appear transiently amongst the undifferentiated cells, before clearly defined preommatidia can be distinguished. The subsequent disappearance of gap junctions may be correlated with cell determination. Lanthanum studies confirm these findings. The later sequential appearance of adhesive junction types is described. These include septate desmosomes and two types of desmosomes. In the fully differentiated ommatidium only two types of junction remain, these are: desmosomes and rhabdomeric junctions.

Cell junctions in the developing compound eye of the desert locust Schistocerca gregaria

Intercellular junctions in the developing retina of the locust Schistocerca gregaria have been examined by electron microscopy. Different types of junction appear in a well-defined sequence during development. Five stages of ommatidial development are described. Close junctions and punctate junctions are present throughout development. Gap junctions appear transiently amongst the undifferentiated cells, before clearly defined preommatidia can be distinguished. The subsequent disappearance of gap junctions may be correlated with cell determination. Lanthanum studies confirm these findings.

The later sequential appearance of adhesive junction types is described. These include septate desmosomes and two types of desmosomes. In the fully differentiated ommatidium only two types of junction remain, these are: desmosomes and rhabdomeric junctions.