High resolution magnetic field measurements in hydrogen and helium plasmas using active laser spectroscopy

Passive spectroscopic measurements of Zeeman splitting have been used reliably to measure magnetic fields in plasmas for decades. However, a requirement is that the field magnitude must be sufficiently strong to be resolved over Doppler and instrument broadening (typically >10 000 G). A diagnostic for measuring magnetic fields spectroscopically well below this limit (>20 G) with high sensitivity has been developed at the Oak Ridge National Laboratory. The diagnostic relies on measuring a high resolution spectral profile using Doppler-free saturation spectroscopy (DFSS) and then fitting the spectrum to a quantum mechanical model. DFSS is an active, laser based technique that greatly reduces the influence of Doppler broadening and eliminates instrument broadening. To date, the diagnostic has been successfully employed to measure the magnetic field in magnetized (550-900 G), low-temperature (5-10 eV), low-density (10¹⁰-10¹² cm^-3), hydrogen and helium plasmas in the 5-200 mTorr pressure range using a low power (25 mW) diode laser. Implementing an approximate crossover resonance model, the measurements are shown to be accurate within 5 G for helium and 83 G for hydrogen. The accuracy in hydrogen can be improved to 39 G if the crossover resonances are neglected. A more robust crossover model can decrease this error to <1 G.

A review of 500 patients with acute stroke admitted to the University Hospital of Saudi Arabia. Similarities and differences compared with the published literature

Published studies have shown differences in types and underlying mechanisms of stroke between different regions of the world. There is a lack of published literature describing the characteristics of acute stroke in Saudi Arabia. The aim of this study was to identify different types and associated risk factors among acute stroke patients in Saudi Arabia. In this descriptive study, records of 500 patients with acute stroke were included. Acute stroke was classified as ischemic stroke, intracerebral hemorrhage, cerebral venous sinus thrombosis or subarachnoid hemorrhage. The TOAST classification was used to categorize ischemic stroke. Ischemic stroke was found to be the most common type (86.6%). The patients included comprised 326 (65.2%) males and 174 (34.8%) females. Small vessel occlusive disease was the most common etiology of ischemic stroke. The males had a lower mean age than the females (p=0.00). The results of our study are largely in agreement with published literature, although a few differences emerged which need to be verified through further prospective multicenter studies.

Comparative study of magnetic resonance defaecography and evacuation proctography in the evaluation of obstructed defaecation

AIM

Obstructed defaecation syndrome is a common condition of multifactorial aetiology and requires specialized evaluation. Accurate and reproducible pelvic floor imaging is imperative for multidisciplinary decision-making. Evacuation proctography (EP) and magnetic resonance defaecography (MRD) are the main imaging modalities used to assess dynamic pelvic floor function. The aim of this prospective study was to compare the findings and acceptability of MRD and EP in the same cohort of patients.

METHOD

This was a prospective comparative study of MRD vs EP in 55 patients with obstructed defaecation syndrome in a single National Health Service Foundation Trust.

RESULTS

Fifty-five patients were recruited and underwent both EP and MRD. Detection rates for rectocoele were similar (82% vs 73%, P = 0.227), but EP revealed a significantly higher number of trapping rectocoeles compared to MRD (75% vs 31%, P < 0.001). EP detected more rectal intussusceptions than MRD (56% vs 35%, P = 0.023). MRD appeared to underestimate the size of the identified rectocoele, although it detected a significant number of anatomical abnormalities in the middle and anterior pelvic compartment not seen on EP (1.8% enterocoele, 9% peritoneocoele and 20% cystocoele). Patients achieved higher rates of expulsion of rectal contrast during EP compared to MRD, but this difference was not significant (76% vs 64% in MRD, P = 0.092). Of the two studies, patients preferred MRD.

CONCLUSIONS

MRD provides a global assessment of pelvic floor function and anatomical abnormality. MRD is better tolerated by patients but it is not as sensitive as EP in detecting trapping rectocoeles and intussusceptions.

Pattern of first- and second-line drug resistance among pulmonary tuberculosis retreatment cases in Pakistan

BACKGROUND

Drug resistance in general, and multidrug-resistant tuberculosis (MDR-TB) in particular, threatens global tuberculosis (TB) control efforts. Population-based estimates of drug resistance are needed to develop strategies for controlling drug-resistant TB in Pakistan.

OBJECTIVE

To obtain population-based data on Mycobacterium tuberculosis drug resistance in Pakistan.

METHODS

To obtain drug resistance data, we conducted a population-based study of TB cases in all provinces of Pakistan. We performed culture and drug susceptibility testing on M. tuberculosis isolates from patients with a prior history of anti-tuberculosis treatment (retreatment cases) from all over the country.

RESULTS

Of 544 isolates from previously treated cases, 289 (53.1%) were susceptible to all first-line drugs, 255 (46.9%) were resistant to at least one anti-tuberculosis drug and 132 (24.3%) were MDR-TB. Among MDR-TB isolates, 47.0% were ofloxacin (OFX) resistant. Extensively drug-resistant TB was found in two (0.4%) isolates.

CONCLUSION

Prevalence of drug resistance in retreatment isolates was high. The alarmingly high prevalence of OFX resistance among MDR-TB isolates may threaten the success of efforts to control and treat MDR-TB.

Layer-number dependent and structural defect related optical properties of InSe

We present systematic investigations on the layer-dependent optical properties of InSe and modify its excitonic states by electron beam irradiation.

All The Catalytic Active Sites of MoS2 for Hydrogen Evolution

MoS₂ presents a promising low-cost catalyst for the hydrogen evolution reaction (HER), but the understanding about its active sites has remained limited. Here we present an unambiguous study of the catalytic activities of all possible reaction sites of MoS₂, including edge sites, sulfur vacancies, and grain boundaries. We demonstrate that, in addition to the well-known catalytically active edge sites, sulfur vacancies provide another major active site for the HER, while the catalytic activity of grain boundaries is much weaker. The intrinsic turnover frequencies (Tafel slopes) of the edge sites, sulfur vacancies, and grain boundaries are estimated to be 7.5 s^-1 (65-75 mV/dec), 3.2 s^-1 (65-85 mV/dec), and 0.1 s^-1 (120-160 mV/dec), respectively. We also demonstrate that the catalytic activity of sulfur vacancies strongly depends on the density of the vacancies and the local crystalline structure in proximity to the vacancies. Unlike edge sites, whose catalytic activity linearly depends on the length, sulfur vacancies show optimal catalytic activities when the vacancy density is in the range of 7-10%, and the number of sulfur vacancies in high crystalline quality MoS₂ is higher than that in low crystalline quality MoS₂, which may be related with the proximity of different local crystalline structures to the vacancies.

Antibiotic susceptibility in Streptococcus pneumoniae, Haemophilus influenzae and Streptococcus pyogenes in Pakistan: a review of results from the Survey of Antibiotic Resistance (SOAR) 2002-15

OBJECTIVES

To investigate changes in the antibiotic susceptibility of Streptococcus pneumoniae, Haemophilus influenzae and Streptococcus pyogenes from the Survey of Antibiotic Resistance (SOAR) in community-acquired respiratory tract infections (CA-RTIs) between 2002 and 2015 in Pakistan.

METHODS

This is a review based on previously published studies from 2002-03, 2004-06 and 2007-09 and also new data from 2014-15. Susceptibility was determined by Etest(®) or disc diffusion according to CLSI and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.

RESULTS

A total of 706 isolates from CA-RTIs comprising 381 S. pneumoniae, 230 H. influenzae and 95 S. pyogenes were collected between 2002 and 2015 and tested against a range of antibiotics. Antibiotic resistance in S. pneumoniae rose steeply from 2002 to 2009, with isolates non-susceptible to penicillin and macrolides increasing from 10% to 34.1% and from 13%-14% to 29.7%, respectively. Susceptibility to amoxicillin/clavulanic acid (and by inference amoxicillin) remained between 99.4% and 100% from 2002 to 2015. Over the years, the prevalence of susceptibility to cefuroxime was 98%-100% among S. pneumoniae. Resistance in S. pneumoniae to some older antibiotics between 2007 and 2009 was high (86.8% for trimethoprim/sulfamethoxazole and 57.2% for tetracycline). Between 2002 and 2015, ampicillin resistance (β-lactamase-positive strains) among H. influenzae has remained low (between 2.6% and 3.2%) and almost unchanged over the years (H. influenzae was not tested during 2004-06). For S. pyogenes isolates, macrolide resistance reached 22%; however, susceptibility to penicillin, amoxicillin/clavulanic acid and cefuroxime remained stable at 100%.

CONCLUSIONS

In S. pneumoniae from Pakistan, there has been a clear reduction in susceptibility to key antibiotics since 2002, but not to amoxicillin/clavulanic acid (amoxicillin) or cefuroxime. However, susceptibility in H. influenzae has remained stable. Local antibiotic susceptibility/resistance data are essential to support informed prescribing for CA-RTIs and other infections.

Intracranial venous thrombosis in a man taking clomiphene citrate

Clomiphene citrate is widely used by the female population for the management of a wide array of medical conditions especially those related to ovulation, but its use in male population remains controversial. Efficacy of clomiphene is not well established in male hypogonadism and infertility. Its side effects and complications are also poorly studied or reported. We present a case of a man with infertility issues for which he started receiving clomiphene citrate 3 weeks before presenting with progressive symptoms of headache, vomiting, transient blurred vision and diplopia, which eventually turned out to be the symptoms of intracranial venous thrombosis. After excluding the common causes of intracranial venous thrombosis and hypercoagulable state, clomiphene citrate seems the most likely culprit.

Applications of Doppler-free saturation spectroscopy for edge physics studies (invited)

Doppler-free saturation spectroscopy provides a very powerful method to obtain detailed information about the electronic structure of the atom through measurement of the spectral line profile. This is achieved through a significant decrease in the Doppler broadening and essentially an elimination of the instrument broadening inherent to passive spectroscopic techniques. In this paper we present the technique and associated physics of Doppler-free saturation spectroscopy in addition to how one selects the appropriate transition. Simulations of H_δ spectra are presented to illustrate the increased sensitivity to both electric field and electron density measurements.

A temporally and spatially resolved electron density diagnostic method for the edge plasma based on Stark broadening

An electron density diagnostic (≥10¹⁰ cm^-3) capable of high temporal (ms) and spatial (mm) resolution is currently under development at Oak Ridge National Laboratory. The diagnostic is based on measuring the Stark broadened, Doppler-free spectral line profile of the n = 6-2 hydrogen Balmer series transition. The profile is then fit to a fully quantum mechanical model including the appropriate electric and magnetic field operators. The quasi-static approach used to calculate the Doppler-free spectral line profile is outlined here and the results from the model are presented for H-δ spectra for electron densities of 10¹⁰-10¹³ cm^-3. The profile shows complex behavior due to the interaction between the magnetic substates of the atom.

Assessment of response rates and yields for Two opportunistic Tools for Early detection of Non-diabetic hyperglycaemia and Diabetes (ATTEND). A randomised controlled trial and cost-effectiveness analysis

AIMS

To assess the opportunistic use in primary care of a computer risk score versus a self-assessment risk score for undiagnosed type 2 diabetes.

METHODS

We conducted a randomised controlled trial in 11 primary care practices in the UK. 577 patients aged 40-75years with no current diagnosis of type 2 diabetes were recruited to a computer based risk score (Leicester Practice Computer Risk Score (LPCRS)) or a patient self-assessment score (Leicester Self-Assessment Score (LSAS)).

RESULTS

The rate of self-referral blood tests was significantly higher for the LPCRS compared to the LSAS, 118.98 (95% CI: 102.85, 137.64) per 1000 high-risk patient years of follow-up compared to 92.14 (95% CI: 78.25, 108.49), p=0.022. Combined rate of diagnosis of type 2 diabetes and those at risk of developing the disease (i.e. impaired glucose tolerance (IGT) or impaired fasting glucose (IFG)) was similar between the two arms, 15.12 (95% CI: 9.11, 25.08) per 1000 high-risk patient years for LPCRS compared to 14.72 (95% CI: 9.59, 22.57) for the LSAS, p=0.699. For the base case scenario the cost per new case of type 2 diabetes diagnosed was lower for the LPCRS compared to the LSAS, £168 (95% Credible Interval (CrI): 76, 364), and £352 (95% CrI: 109, 1148), respectively.

CONCLUSIONS

Compared to a self-assessment risk score, a computer based risk score resulted in greater attendance to an initial blood test and is potentially more cost-effective.

Identification of chromatin accessibility domains in human breast cancer stem cells

Epithelial-to-mesenchymal transition (EMT) is physiological in embryogenesis and wound healing but also associated with the formation of cancer stem cells (CSCs). Many EMT signaling pathways are implicated in CSC formation, but the precise underlying mechanisms of CSC formation remain elusive. We have previously demonstrated that PKC is critical for EMT induction and CSC formation in inducible breast EMT/CSC models. Here, we used formaldehyde-assisted isolation of regulatory elements-sequencing (FAIRE-seq) to investigate DNA accessibility changes after PKC activation and determine how they influence EMT and CSC formation. During EMT, DNA accessibility principally increased in regions distant from transcription start sites, low in CpG content, and enriched with chromatin enhancer marks. ChIP-sequencing revealed that a subset of these regions changed from poised to active enhancers upon stimulation, with some even more acteylated in CSCs. While regions with increased accessibility were enriched for FOX, AP-1, TEAD, and TFAP2 motifs, those containing FOX and AP-1 motif were associated with increased expression of CSC-associated genes, while those with TFAP2 were associated with genes with increased expression in non-CSCs. Silencing of 2 members of the FOX family, FOXN2 and FOXQ1, repressed CSCs and the mesenchymal phenotype and inhibited the CSC gene signature. These novel, PKC-induced DNA accessibility regions help explain how the epigenomic plasticity of cells undergoing EMT leads to CSC gene activation.

Estimating genetic potential of biofuel forest hardwoods to withstand metal toxicity in industrial effluent under dry tropical conditions

Biofuel tree species are recognized as a promising alternative source of fuel to conventional forms. Additionally, these tree species are also effective in accumulating toxic heavy metals present in some industrial effluents. In developing countries such as Pakistan, the use of biofuel tree species is gaining popularity not only for harvesting economical and environmentally friendly biofuel, but also to sequester poisonous heavy metals from industrial wastewater. This study was aimed at evaluating the genetic potential of two biofuel species, namely, Jatropha curcas and Pongamia pinnata, to grow when irrigated with industrial effluent from the Pak-Arab Fertilizer Factory Multan, Southern Punjab, Pakistan. The growth performances of one-year-old seedlings of both species were compared in soil with adverse physiochemical properties. It was found that J. curcas was better able to withstand the toxicity of the heavy metals present in the fertilizer factory effluent. J. curcas showed maximum gain in height, diameter, and biomass production in soil irrigated with 75% concentrated industrial effluent. In contrast, P. pinnata showed a significant reduction in growth in soil irrigated with more than 50% concentrated industrial effluent, indicating that this species is less tolerant to higher toxicity levels of industrial effluent. This study identifies J. curcas as a promising biofuel tree species that can be grown using industrial wastewater.

Acknowledging and allocating responsibility for clinical inertia in the management of Type 2 diabetes in primary care: a qualitative study

AIMS

Failure to intensify treatment in patients with Type 2 diabetes with suboptimal blood glucose control has been termed clinical inertia and has been shown to contribute to poorer patient outcomes. We aimed to identify and explore perceptions about clinical inertia from the perspective of primary healthcare providers.

METHODS

A qualitative study was conducted in Leicestershire and Northamptonshire, UK. Purposive sampling was based on healthcare providers working in primary care settings with 'higher' and 'lower' target achievement based on routine data. Twenty semi-structured interviews were conducted, face-to-face or by telephone. Thematic analysis was informed by the constant comparative approach.

RESULTS

An important broad theme that emerged during the analysis was related to attribution and explanation of responsibility for clinical inertia. This included general willingness to accept a degree of responsibility for clinical inertia. In some cases, however, participants had inaccurate perceptions about levels of target achievement in their primary care centres, as indicated by routine data. Participants sought to lessen their own sense of accountability by highlighting patient-level barriers such as comorbidities and human fallibility, and also system-level barriers, particularly time constraints. Perceptions about ways of addressing the problem of clinical inertia were not seen as straightforward, further emphasizing a complex and cumulative pattern of barriers.

CONCLUSIONS

In order to understand and address the problem of clinical inertia, provider, patient- and system-level barriers should be considered together rather than as separate issues. Acknowledgement of responsibility should be regarded positively as a motivator for change.

To explore a new class of material (X-type hexaferrites) for N2O decomposition

Monophasic X-type Mn- and Cr-doped Ba–Co ferrites, synthesized by co-precipitation, catalytically decomposed N₂O gas while remaining stable at 1000 K.

Fluoroquinolone and macrolide co-resistance in clinical isolates of Campylobacter species: a 15-year study in Karachi, Pakistan

Fluoroquinolone and macrolide antibiotics are generally considered as first-line drugs for the treatment of severe campylobacteriosis. This study was conducted to analyse the trend of erythromycin and ofloxacin resistance among Campylobacter spp. isolated from stool specimens over a period of 15 years (1992-2007) at The Aga Khan University clinical laboratory in Karachi, Pakistan. A total of 83 396 stool specimens were processed, with a 14% isolation rate for enteric pathogens. The isolation rate of Campylobacter spp. was low during 1992-93 (6%-13%), peaked in 1996 (46%), then ranged from 20% to 40%. We report a rising trend in ofloxacin resistance, re-emergence of erythromycin resistance and indications of co-resistance to both drugs in clinical isolates of Campylobacter spp.