Pressure-Temperature Phase Diagram Reveals Spin-Lattice Interactions in Co[N(CN)2]2.

Diamond anvil cell techniques, synchrotron-based infrared and Raman spectroscopies, and lattice dynamics calculations are combined with prior magnetic property work to reveal the pressure-temperature phase diagram of Co[N(CN)2]2. The second-order structural boundaries converge on key areas of activity involving the spin state exposing how the pressure-induced local lattice distortions trigger the ferromagnetic → antiferromagnetic transition in this quantum material.

High Pressure Vibrational Properties of WS2 Nanotubes.

We bring together synchrotron-based infrared and Raman spectroscopies, diamond anvil cell techniques, and an analysis of frequency shifts and lattice dynamics to unveil the vibrational properties of multiwall WS2 nanotubes under compression. While most of the vibrational modes display similar hardening trends, the Raman-active A1g breathing mode is almost twice as responsive, suggesting that the nanotube breakdown pathway under strain proceeds through this displacement. At the same time, the previously unexplored high pressure infrared response provides unexpected insight into the electronic properties of the multiwall WS2 tubes. The development of the localized absorption is fit to a percolation model, indicating that the nanotubes display a modest macroscopic conductivity due to hopping from tube to tube.

Magnetoelectric Coupling through the Spin Flop Transition in Ni_{3}TeO_{6}.

We combined high field optical spectroscopy and first principles calculations to analyze the electronic structure of Ni_{3}TeO_{6} across the 53 K and 9 T magnetic transitions, both of which are accompanied by large changes in electric polarization. The color properties are sensitive to magnetic order due to field-induced changes in the crystal field environment, with those around Ni1 and Ni2 most affected. These findings advance the understanding of magnetoelectric coupling in materials in which magnetic 3d centers coexist with nonmagnetic heavy chalcogenide cations.

The cost of treatment failure: resource use and costs incurred by hepatitis C virus genotype 1-infected patients who do or do not achieve sustained virological response to therapy.

Chronic hepatitis C virus (HCV) infection places a considerable economic burden on health services. Cost-effectiveness analyses of antiviral treatment for patients with chronic HCV infection are dependent on assumptions about cost reductions following sustained virological response (SVR) to therapy. This study quantified the medium-term difference in health resource usage and costs depending on treatment outcome. Retrospective chart review of patients with HCV genotype 1 infection who had received at least 2 months pegylated interferon and ribavirin therapy, with known treatment outcome was conducted. Disease status was categorized as chronic hepatitis, cirrhosis or decompensated liver disease. Health resource use was documented for each patient in each disease state. Unit costs were from the NHS 'Payment by Results' database and the British National Formulary. One hundred and ninety three patients (108 SVR, 85 non-SVR) with mean follow-up of 3.5 (SVR) and 4.9 (non-SVR) years were enrolled. No SVR patient progressed to a more severe liver disease state. Annual transition rates for non-SVR patients were 7.4% (chronic hepatitis to cirrhosis) and 4.9% (cirrhosis to decompensated liver disease). By extrapolation of modelled data over a 5-year post-treatment period, failure of patients with chronic hepatitis to achieve SVR was associated with a 13-fold increase (roughly £2300) in costs, whilst for patients who were retreated, the increase was 56-fold, equating to more than £10 000. Achievement of an SVR has significant effects on health service usage and costs. This work provides real-life data for future cost-effectiveness analyses related to the treatment for chronic HCV infection.

Size-dependent vibronic coupling in α-Fe2O3.

We report the discovery of finite length scale effects on vibronic coupling in nanoscale α-Fe2O3 as measured by the behavior of vibronically activated d-d on-site excitations of Fe(3+) as a function of size and shape. An oscillator strength analysis reveals that the frequency of the coupled symmetry-breaking phonon changes with size, a crossover that we analyze in terms of increasing three-dimensional character to the displacement pattern. These findings demonstrate the flexibility of mixing processes in confined systems and suggest a strategy for both enhancing and controlling charge-lattice interactions in other materials.

Prevalence and risk factors for hepatitis C virus infection in Kech District, Balochistan, Pakistan: most infections remain unexplained. A cross-sectional study.

We studied a cross-sectional sample of the population of Kech, a small rural town in Pakistan to determine the prevalence and risk factors for hepatitis C infection. The prevalence of hepatitis C was 110 out of 2000 persons (5·5%, 95% confidence interval 4·5-6·5). Higher rates were identified in males. Independent risk factors identified were age ≥75 years, being a healthcare worker, and injecting drug use. There was a high prevalence of many potential routes of transmission of bloodborne viruses and most people reported at least one potential risk factor.

Molecular epidemiology of human Campylobacter jejuni shows association between seasonal and international patterns of disease.

We sought to explain seasonality and other aspects of Campylobacter jejuni epidemiology by integrating population genetic and epidemiological analysis in a large 3-year longitudinal, two-centre, population-based study. Epidemiological information was collected for 1505 isolates, which were multilocus sequence-typed. Analyses compared pathogen population structure between areas, over time, and between clinical presentations. Pooled analysis was performed with published international datasets. Subtype association with virulence was not observed. UK sites had nearly identical C. jejuni populations. A clade formed by ST45 and ST283 clonal complexes showed a summer peak. This clade was common in a Finnish dataset but not in New Zealand and Australian collections, countries with less marked seasonality. The UK, New Zealand and Australian collections were otherwise similar. These findings map to known in-vitro differences of this clade. This identifies a target for studies to elucidate the drivers of the summer peak in human C. jejuni infection.

Autoantibodies in chronic hepatitis C virus infection and their association with disease profile.

Autoantibodies are commonly detected in chronic hepatitis C (HCV) but their significance remains uncertain. We assessed the prevalence of anti-nuclear (ANA) and anti-smooth muscle (ASM) antibodies within a cohort of 963 treatment-naïve HCV patients. We also assessed for differences between autoantibody-positive and autoantibody-negative patients in demographics, markers of disease activity and response to anti-viral treatment. One hundred and seventy-two patients (17.9%) had at least one autoantibody, of which were 104 (10.8%) ASM, 54 (5.6%) ANA and 14 (1.5%) positive for both. Autoantibody-positive patients were older (43 vs 39 years, P = 0.001) caused by an age-related increase in ANA (but not ASM). There were no differences in gender, alcohol intake, ethnicity or viral genotype. The presence of autoantibodies, and specifically ASM, was associated with an increase in interface hepatitis score amongst men (1.1 vs 0.8, P = 0.005) but no difference in other necroinflammatory measures, liver function tests or immunoglobulins (Ig). There was no difference in initial fibrosis stage or rate of fibrosis progression. Autoantibodies did not affect response to anti-viral treatment. We conclude that autoantibodies are frequent in HCV infection. Anti-nuclear antibodies increase with age, whereas ASM antibodies are associated with interface hepatitis in men. Neither autoantibody carries increased risk of fibrosis progression or failure of therapy.

Psychological and colonic factors in painful diverticulosis.

BACKGROUND: The importance of psychological factors in symptom expression in diverticulosis is unknown. This follow-up study assessed the relative importance of colonic and psychological factors in symptom expression. METHODS: Patients with barium enema-proven diverticula were sent a bowel symptom questionnaire in 1999 and again in 2006 with additional psychological questionnaires included. RESULTS: Some 170 of 261 initial responders were eligible for follow-up and 124 (72.9 per cent) provided complete replies. Forty-two (33.9 per cent) of 124 respondents experienced recurrent abdominal pain a median of 3.5 (interquartile range (i.q.r.) 2.00-9.25) days per month, with a median duration of 1 (i.q.r. 0.7-2) h. Multivariable analysis identified a history of acute diverticulitis (odds ratio 3.98; P = 0.010) and a raised score on the Hospital Anxiety and Depression Scale (odds ratio 2.53; P = 0.030) as the best predictors of recurrent pain. CONCLUSION: Psychological and colonic factors are important in symptom expression in diverticulosis.

Relationships between structural and functional measures of nutritional status in a normally nourished population.

BACKGROUND AND AIMS: Both anthropometric and functional measurements have been used in nutritional assessment and monitoring. Hand dynamometry is a predictor of surgical outcome and peak expiratory flow rate has been used as an index of respiratory muscle function. This study aims to measure in normal subjects the relationship between anthropometric measurements, voluntary muscle strength by hand grip dynamometry and respiratory muscle function by peak expiratory flow rate. METHODS: Ninety-eight subjects (46 male, 52 female) with a mean age of 45.9 years were studied. Hand grip strength was measured in the dominant and non-dominant hands with a portable strain-gauge dynamometer. Peak expiratory flow rate was measured using a mini-Wright peak flow meter. Three readings were taken, each 1 min apart, and the average recorded. Midarm muscle circumference (MAMC) was derived from triceps skin fold thickness and midarm circumference (MAC) using standard anthropometric techniques. Statistical relationships were measured with Pearson's coefficient of correlation. RESULTS: In both sexes there was significant correlation between hand grip strength in the dominant and non-dominant hands and peak expiratory flow rate (P<0.001). In men, there was a positive correlation between MAMC, hand grip strength (P<0.001) and peak expiratory flow rate (P<0.001). In women muscle function correlated with height (P<0.001) but not MAMC (P>0.05). CONCLUSIONS: In normal subjects bedside tests of skeletal and respiratory muscle function correlated with each other in both sexes, and with muscle mass in men but not in women.

A practical posture for hand grip dynamometry in the clinical setting.

BACKGROUND & AIMS: The optimal testing position for hand grip strength, which is a useful functional measure of nutritional status, is open to debate. We therefore examined the systematic difference between different postures in order to establish a methodology that is clinically relevant, easy to perform and reproducible. METHODS: Grip strength was measured in the dominant and non-dominant hands with a strain gauge dynamometer in three positions: lying at 30 degrees in bed with elbows supported, seated in an armchair with elbows supported and in a chair with elbows unsupported. The average of three readings made in each position, each 1 min apart, was recorded. RESULTS: 55 normally nourished subjects (26 male) were studied. Mean (95% CI) grip strengths measured in the dominant hand with the subject in bed, sitting in an armchair and sitting in a chair were 45.7 (42.3-49.2), 46.3 (42.9-49.8) and 48.5 (45.4-51.7) kg, respectively for males. Corresponding values for females were 29.4 (27.0-31.8), 29.3 (26.8-31.9) and 31.6 (28.8-34.3) kg. There was no significant difference (Student t-paired test) between measurements made in bed and on an armchair (P = 0.49), but the measurements made in a chair were significantly higher than those made in bed (P = 0.001) and in an armchair (P = 0.004). No statistical difference was present, comparing the three separate measurements in each position (Student t-paired test). CONCLUSIONS: Measurement of grip strength using hand dynamometry is reproducible and consistent. As all patients are not able to sit in a chair with elbows unsupported, in clinical practice it is more practicable to perform hand dynamometry with the elbows supported in a bed or armchair.

Randomized, double-blind, placebo-controlled trial of prednisolone in post-infectious irritable bowel syndrome.

BACKGROUND: Post-infectious irritable bowel syndrome is associated with increased serotonin-containing enterochromaffin cells and lymphocytes in rectal biopsies. Animal studies have suggested that steroids reduce the lymphocyte response and suppress some of the post-infectious changes in neuromuscular function. AIM: To evaluate whether steroids reduce the number of enterochromaffin cells and improve the symptoms of post-infectious irritable bowel syndrome. METHODS: Twenty-nine patients with post-infectious irritable bowel syndrome underwent a randomized, double-blind, placebo-controlled trial of 3 weeks of oral prednisolone, 30 mg/day. Mucosal enterochromaffin cells, T lymphocytes and mast cells were assessed in rectal biopsies before and after treatment, and bowel symptoms were recorded in a daily diary. RESULTS: Initial enterochromaffin cell counts were increased and correlated with initial lamina propria T-lymphocyte counts (r = 0.460, P = 0.014). Enterochromaffin cell counts did not change significantly after either prednisolone (- 0.8% +/- 9.2%) or placebo (7.9% +/- 7.9%) (P = 0.5). Although lamina propria T-lymphocyte counts decreased significantly after prednisolone (22.0% +/- 5.6%, P = 0.003), but not after placebo (11.5% +/- 8.6%, P = 0.1), this was not associated with any significant treatment-related improvement in abdominal pain, diarrhoea, frequency or urgency. CONCLUSIONS: Prednisolone does not appear to reduce the number of enterochromaffin cells or cause an improvement in symptoms in post-infectious irritable bowel syndrome. Other approaches to this persistent condition are indicated.

Problems with solutions: drowning in the brine of an inadequate knowledge base.

BACKGROUND & AIMS: We undertook a telephone questionnaire to determine current fluid prescribing practices and relevant knowledge among surgical preregistration house officers (PRHOs) and senior house officers (SHOs) working in 25 British hospitals. METHODS: One hundred PRHOs were surveyed within 10 days of starting their first job (Group A). Fifty other PRHOs were surveyed 6-8 weeks after starting their first job(Group B) along with 50 surgical SHOs (Group C). Outcome measures included responsibility for prescribing, knowledge of the composition of common intravenous fluids and the principles governing their use. RESULTS: PRHOs were responsible for prescribing in 89% of instances. Only 56% of respondents stated that fluid balance charts were checked on morning ward rounds. Less than half were aware of the sodium content of 0.9% saline or the daily sodium requirement. Although potassium supplements were usually correct, 25% of respondents prescribed two or more litres of 0.9% saline per day, which is far in excess of normal requirements. Although SHOs were more confident (P<0.0001), there was no significant difference between the three groups for most responses. CONCLUSIONS: Inadequate knowledge and suboptimal prescribing of fluid and electrolytes is common. Undergraduate and postgraduate training in this basic patient management skill needs improvement, with particular emphasis on the practical aspects.

Body water compartment measurements: a comparison of bioelectrical impedance analysis with tritium and sodium bromide dilution techniques.

BACKGROUND AND AIMS: This study was undertaken to assess the comparability of body water compartment estimates in healthy volunteers using single and dual frequency bioelectrical impedance analysis (BIA) with established reference methods of tritium and NaBr dilution. METHODS: Total body water (TBW) was estimated in 10 healthy volunteers using single frequency (50 kHz) BIA (Bodystat 1500), dual frequency (5 and 200 kHz) BIA (Bodystat Dualscan 2005) and tritium dilution. Extracellular water (ECW) was measured with dual frequency BIA and NaBr dilution. BIA was performed using distal tetrapolar electrodes in the supine position. Venous blood was sampled for measurement of background concentrations of tritium and NaBr using a beta counter and high performance liquid chromatography respectively. 10 ml tritiated water (3.7 MBq) and 50 ml 5% NaBr solution were then injected intravenously and blood samples taken from the opposite arm every 45 min for 4.5 h for estimation of concentrations of tritium and NaBr. RESULTS: There was good correlation (r(2)=0.76) between estimates of ECW using dual frequency BIA and NaBr dilution, with the former overestimating ECW by approximately 1 L. However, this difference varied systematically with body weight. Although TBW measurements obtained by single and dual frequency BIA correlated well with estimates using tritium dilution (r(2)=0.96 and 0.95 respectively), single frequency BIA underestimated TBW by approximately 1 L and dual frequency BIA by approximately 5 L compared to tritium dilution. CONCLUSION: TBW measurements obtained using the single frequency BIA device were more accurate than those obtained using the dual frequency BIA device. Dual frequency BIA provided a reasonably accurate estimate of ECW.

Reproducibility and normal ranges for gastric emptying in normal volunteers using a test meal designed for post-operative patients.

Scintigraphy is the current gold standard for the quantification of gastric emptying; however, results vary with meal composition. We modified a dual phase meal for administration to patients in the early post-operative period and aimed to test the reproducibility of the method, to obtain normal ranges and to compare these with previous data. Twenty healthy volunteers (10 male, 10 female), studied prospectively, were compared with 10 historical male volunteers. Each volunteer was studied twice (Test 1 at day 0 and Test 2 at day 7-10). After an overnight fast, subjects had Meal A consisting of a 60 g pancake labelled with 3 MBq of non-absorbable 99mTc-ion exchange resin and 100 ml of water labelled with 0.5 MBq of non-absorbable 111In-diethylenetriamine pentaacetic acid (111In-DTPA). Anterior and posterior gamma camera images of the stomach were obtained every 20 min for 3 h. The time for 50% emptying (T50) was derived from time-activity curves. Data obtained for males were compared with historical data using a similar technique with Meal B, consisting of two pancakes and a 200 ml milkshake labelled with identical amounts of radioisotopes. The mean (95% CI) T50 values for solid phase emptying for males and females using Meal A, and for historical males using Meal B, were 51.1 min (44.1-58.1), 58.6 min (52.7-64.5) and 128.9 min (112.8-145.1), respectively. Corresponding figures for the liquid phase were 33.2 min (26.1-40.3), 50.2 min (38.4-62.1) and 30.7 min (21.4-39.9). Bland-Altman plots for each phase showed good agreement between Tests 1 and 2 for Meal A. The modified test meal gave reproducible results in healthy volunteers; however, solid phase emptying was significantly faster than that of the bulkier test meal in historical subjects.

Variations in chemoprophylaxis for meningococcal disease: a retrospective case note review, analysis of routine prescribing data and questionnaire of general practitioners.

BACKGROUND: Invasive meningococcal disease is a significant cause of mortality and morbidity in the UK. Administration of chemoprophylaxis to close contacts reduces the risk of a secondary case. However, unnecessary chemoprophylaxis may be associated with adverse reactions, increased antibiotic resistance and removal of organisms, such as Neisseria lactamica, which help to protect against meningococcal disease. Limited evidence exists to suggest that overuse of chemoprophylaxis may occur. This study aimed to evaluate prescribing of chemoprophylaxis for contacts of meningococcal disease by general practitioners and hospital staff. METHODS: Retrospective case note review of cases of meningococcal disease was conducted in one health district from 1st September 1997 to 31st August 1999. Routine hospital and general practitioner prescribing data was searched for chemoprophylactic prescriptions of rifampicin and ciprofloxacin. A questionnaire of general practitioners was undertaken to obtain more detailed information. RESULTS: Prescribing by hospital doctors was in line with recommendations by the Consultant for Communicable Disease Control. General practitioners prescribed 118% more chemoprophylaxis than was recommended. Size of practice and training status did not affect the level of additional prescribing, but there were significant differences by geographical area. The highest levels of prescribing occurred in areas with high disease rates and associated publicity. However, some true close contacts did not appear to receive prophylaxis. CONCLUSIONS: Receipt of chemoprophylaxis is affected by a series of patient, doctor and community interactions. High publicity appears to increase demand for prophylaxis. Some true contacts do not receive appropriate chemoprophylaxis and are left at an unnecessarily increased risk.

Peri-operative fluid and electrolyte management: a survey of consultant surgeons in the UK.

BACKGROUND: Current peri-operative fluid and electrolyte management in the UK may be suboptimal. We assessed the attitudes of consultant surgeons to fluid and electrolyte prescribing and gathered suggestions for improvement in education on the subject. METHODS: A postal questionnaire survey was sent to 1091 Fellows of the Association of Surgeons of Great Britain and Ireland. Of the 730 (67%) replies, 20 were invalid or incomplete, and 710 (65%) questionnaires were analysed. Outcome measures included provision of guidelines and teaching to junior staff on fluid and electrolyte prescribing, appropriateness of fluid management and suggestions to improve standards. RESULTS: Junior staff were given written guidelines in 22% of instances. Only 16% of respondents felt that their preregistration house officers (PRHOs) were adequately trained in the subject before joining the firm; 15% also stated that PRHOs did not receive much training on their firm. 65% felt that fluid balance charts were accurately maintained, nursing shortages being the commonest reason for inaccuracies. Only 30% felt that postoperative patients were receiving appropriate amounts of water, sodium and potassium. Respondents who had been consultants for > 5 years were more likely to prefer erring on the side of under-replacement of fluid than those who were consultants for 5 years (63% versus 47%, P < 0.0005). Suggestions for improvement in education included problem-oriented ward rounds, written guidelines, and discussion of patient scenarios. CONCLUSIONS: Consultant surgeons feel that present practice in peri-operative fluid management is unsatisfactory. Higher standards within clinical governance and risk management may be achieved by focused practical training combined with formal written guidelines.

Prevalence of gastrointestinal symptoms six months after bacterial gastroenteritis and risk factors for development of the irritable bowel syndrome: postal survey of patients.

OBJECTIVE: To measure the prevalence of gastrointestinal symptoms six months after bacterial gastroenteritis and determine risk factors and associations with postdysenteric symptoms. DESIGN: Postal questionnaire. SETTING: Nottingham Health Authority. SUBJECTS: 544 people with microbiologically confirmed bacterial gastroenteritis between July 1994 and December 1994. MAIN OUTCOME MEASURES: Prevalence of gastrointestinal symptoms and relative risks for development of the irritable bowel syndrome and self reported altered bowel habit. RESULTS: A quarter of subjects reported persistence of altered bowel habit six months after an episode of infective gastroenteritis. Increasing duration of diarrhoea, younger age, and female sex increased this risk, whereas vomiting as part of the illness reduced the risk. One in 14 developed the irritable bowel syndrome with an increased risk seen in women (relative risk 3.4: 95% confidence interval 1.2 to 9.8) and with duration of diarrhoea (6.5; 1.3 to 34 for 15-21 days). CONCLUSIONS: Persistence of bowel symptoms commonly occurs after bacterial gastroenteritis and is responsible for considerable morbidity and health care costs.

Changing carriage rate of Neisseria meningitidis among university students during the first week of term: cross sectional study.

OBJECTIVE: To determine the rates of, and risk factors for, meningococcal carriage and acquisition among university students. DESIGN: Repeated cross sectional study. PARTICIPANTS: 2,507 students in their first year at university. MAIN OUTCOME MEASURES: Prevalence of carriage of meningococci and risk factors for carriage and acquisition of meningococci. RESULTS: Carriage rates for meningoccoci increased rapidly in the first week of term from 6.9% on day 1, to 11.2% on day 2, to 19.0% on day 3, and to 23.1% on day 4. The average carriage rate during the first week of term in October among students living in catered halls was 13.9%. By November this had risen to 31.0% and in December it had reached 34. 2%. Independent associations for acquisition of meningococci in the autumn term were frequency of visits to a hall bar (5-7 visits: odds ratio 2.7, 95% confidence interval 1.5 to 4.8), active smoking (1.6, 1.0 to 2.6), being male (1.6, 1.2 to 2.2), visits to night clubs (1. 3, 1.0 to 1.6), and intimate kissing (1.4, 1.0 to 1.8). Lower rates of acquisition were found in female only halls (0.5, 0.3 to 0.9). The most commonly acquired meningococcal strain was C2a P1.5 (P1.2), which has been implicated in clusters of invasive meningococcal disease at other UK universities. CONCLUSIONS: Carriage rates of meningococci among university students increase rapidly in the first week of term, with further increases during the term. The rapid rate of acquisition may explain the increased risk of invasive meningococcal disease and the timing of cases and outbreaks in university students.

The Patient Health Questionnaire 12 Somatic Symptom scale as a predictor of symptom severity and consulting behaviour in patients with irritable bowel syndrome and symptomatic diverticular disease.

BACKGROUND: Anxiety, depression and nongastrointestinal symptoms are often prominent in irritable bowel syndrome (IBS), but their relative value in patient management has not been quantitatively assessed. We modified the Patient Health Questionnaire 15 (PHQ-15) by excluding three gastrointestinal items to create the PHQ-12 Somatic Symptom (PHQ-12 SS) scale. AIMS: To compare the value of the PHQ-12 SS scale with the Hospital Anxiety and Depression (HAD) scale in predicting symptoms and patient behaviour in IBS and diverticular disease. METHODS: We compared 151 healthy volunteers (HV), 319 IBS patients and 296 patients with diverticular disease (DD), 113 asymptomatic [ASYMPDD] and 173 symptomatic DD (SYMPDD). RESULTS: Patient Health Questionnaire 12 SS scores for IBS and SYMPDD were significantly higher than HV. Receiver-operator curves showed a PHQ-12 SS >6, gave a sensitivity for IBS of 66.4% with a specificity of 94.7% and a positive likelihood ratio (PLR) = 13.2, significantly better than that associated with an HAD anxiety score >7, PLR = 3.0 and depression score >7 PLR = 6.5. PHQ-12 SS correlated strongly with IBS severity scale and GP visits in both IBS and DD. CONCLUSION: The PHQ-12 SS scale is a useful clinical tool which correlates with patient behaviour in both IBS and symptomatic DD.