Growth optimization and crossover of transport mechanisms in Bi2Se3thin films

We report the growth, structural characterization, and transport studies of Bi2Se3thin film on single crystalline silicon (Si), Si/SiO2, quartz, and glass substrates by thermal evaporation method. Our results show that 300 °C is the optimum substrate temperature to obtain thec-axis (001) oriented Bi2Se3films on all the substrates. The film grown on the Si substrate has the minimum crystalline disorder. The energy-dispersive x-ray spectroscopy results show that film on Si substrate is bismuth deficient, the film on Si/SiO2substrate is selenium deficient, and the film on quartz substrate is near perfect stoichiometric providing a way to tune the electronic properties of Bi2Se3films through substrate selection. The film grown on quartz shows the highest mobility (2.7 × 104cm2V-1s-1) which drops to 150 cm2V-1s-1for Si, 60 cm2V-1s-1for Si/SiO2, and 0.9 cm2V-1s-1for glass substrate. Carrier concentration is n-type for Bi2Se3films on Si (∼1018cm-3), quartz (∼1018cm-3) and Si/SiO2(∼1019cm-3) substrate with a clear indication of frozen out effect around 50 K for Si/SiO2and Si substrate. Longitudinal resistivity of Bi2Se3film on Si/SiO2substrate shows different behavior in three different temperature regions: temperature dependent resistivity region due to electron-phonon scattering, a nearly temperature independent resistivity region due to electron-phonon and electron-ion scattering, and a quantum coherent transport region.

A systematic review of qualitative research exploring patient and health professional perspectives of breakthrough cancer pain

PURPOSE

Breakthrough cancer pain (BtCP) is a prevalent health issue which is difficult to manage. A plethora of quantitative research in this area exists. There is a paucity of research on the perspectives of health professionals and patients surrounding domains impacting effective treatment, including definitions of BtCP, treatment, and education opportunities. This review aims to identify and synthesize the extent of qualitative research exploring health professional and patient perspectives of BtCP.

METHODS

A systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach was undertaken. The approach was registered with Prospero. MEDLINE, EMBASE, and Web of Science were searched for peer-reviewed literature published any date prior to May 19, 2022. Eligible sources must have considered health professional and/or patient perspectives of BtCP. A narrative synthesis approach was utilized.

RESULTS

Three sources met the review criteria. One source explored nurse perspectives, while two sources explored patient perspectives. Study quality was moderate to high. Overlapping themes across the three studies included communication, defining BtCP, impact of BtCP, management of BtCP, perceptions of BtCP, analgesia and pain relief, and training and professional development.

CONCLUSION

Given limited research investigating clinician and patient perspectives of BtCP, a rich understanding informed by exploratory qualitative methods around identification, best management strategies, professional development, and factors promoting and inhibiting best practice remains unclear. Further qualitative inquiry is warranted, and it is expected such research will inform BtCP clinical guidelines.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Experimental and Theoretical Investigations of Fe-Doped Hexagonal MnNiGe

We report a comprehensive investigation of MnNi_0.7Fe_0.3Ge Heusler alloy to explore its magnetic, caloric, and electrical transport properties. The alloy undergoes a ferromagnetic transition across T _C ∼ 212 K and a weak-antiferromagnetic transition across T _t ∼ 180 K followed by a spin-glass transition below T _f ∼ 51.85 K. A second-order phase transition across T _C with mixed short and long-range magnetic interactions is confirmed through the critical exponent study and universal scaling of magnetic entropy and magnetoresistance. A weak first-order phase transition is evident across T _t from magnetization and specific heat data. The frequency dependent cusp in χ_AC(T) along with the absence of a clear magnetic transition in specific heat C(T) and resistivity ρ(T) establish the spin glass behavior below T _f. Mixed ferromagnetic and antiferromagnetic interactions with dominant ferromagnetic coupling, as revealed by density functional calculations, are experimentally evident from the large positive Weiss temperature, magnetic saturation, and negative magnetic-entropy and magnetoresistance.

Noninvasive three-state sleep-wake staging in mice using electric field sensors

STUDY OBJECTIVE

Validate a novel method for sleep-wake staging in mice using noninvasive electric field (EF) sensors.

METHODS

Mice were implanted with electroencephalogram (EEG) and electromyogram (EMG) electrodes and housed individually. Noninvasive EF sensors were attached to the exterior of each chamber to record respiration and other movement simultaneously with EEG, EMG, and video. A sleep-wake scoring method based on EF sensor data was developed with reference to EEG/EMG and then validated by three expert scorers. Additionally, novice scorers without sleep-wake scoring experience were self-trained to score sleep using only the EF sensor data, and results were compared to those from expert scorers. Lastly, ability to capture three-state sleep-wake staging with EF sensors attached to traditional mouse home-cages was tested.

RESULTS

EF sensors quantified wake, rapid eye movement (REM) sleep, and non-REM sleep with high agreement (>93%) and comparable inter- and intra-scorer error as EEG/EMG. Novice scorers successfully learned sleep-wake scoring using only EF sensor data and scoring criteria, and achieved high agreement with expert scorers (>91%). When applied to traditional home-cages, EF sensors enabled classification of three-state (wake, NREM and REM) sleep-wake independent of EEG/EMG.

CONCLUSIONS

EF sensors score three-state sleep-wake architecture with high agreement to conventional EEG/EMG sleep-wake scoring 1) without invasive surgery, 2) from outside the home-cage, and 3) and without requiring specialized training or equipment. EF sensors provide an alternative method to assess rodent sleep for animal models and research laboratories in which EEG/EMG is not possible or where noninvasive approaches are preferred.

Enhanced Thermoelectric Performance of Novel Reaction Condition-Induced Bi2S3-Bi Nanocomposites

This is the first report on the enhanced thermoelectric (TE) properties of novel reaction-temperature (T_Re) and duration-induced Bi₂S₃-Bi nanocomposites synthesized using a facile one-step polyol method. They are well characterized as nanorod composites of orthorhombic Bi₂S₃ and rhombohedral Bi phases in which the latter coats the former forming Bi₂S₃-Bi core-shell-like structures along with independent Bi nanoparticles. A very significant observation is the systematic reduction in electrical resistivity ρ with a whopping 7 orders of magnitude (∼10⁷) with just reaction temperature and duration increase, revealing a promising approach for the reduction of ρ of this highly resistive chalcogenide and hence resolving the earlier obstacles for its thermoelectric application potentials in the past few decades. Most astonishingly, a TE power factor at 300 K of the highest Bi content nanocomposite pellet, made at 27 °C using ∼900 MPa pressure, is 3 orders of magnitude greater than that of hot-pressed Bi₂S₃. Its highest ZT at 325 K of 0.006 is over twice of that of similarly prepared CuS or Ag₂S-based nanocomposites. A significantly improved TE performance potential near 300 K is demonstrated for these toxic-free and rare-earth element-free TE nanocomposites, making the present synthesis method as a pioneering approach for developing enhanced thermoelectric properties of Bi₂S₃-based materials without extra sintering steps.

Scaling analysis of anomalous Hall resistivity in the Co2TiAl Heusler alloy

A comprehensive magnetotransport study including resistivity (ρxx), isothermal magnetoresistance, Hall resistivity (ρxy) and magnetization have been carried out at different temperatures on the Co2TiAl Heusler alloy. Co2TiAl alloy shows a paramagnetic to ferromagnetic (FM) transition below the Curie temperature (TC) ∼ 125 K. In the FM region, resistivity and magnetoresistance reveal a spin flip electron-magnon scattering and the Hall resistivity unveils the anomalous Hall resistivity. Scaling of anomalous Hall resistivity with resistivity establishes the extrinsic scattering process responsible for the anomalous Hall resistivity; however skew scattering is the dominant mechanism compared to the side-jump contribution. A one to one correspondence between magnetoresistance and side-jump contribution to anomalous Hall resistivity verifies the electron-magnon scattering being the source of side-jump contribution to the anomalous Hall resistivity.

Anomalous Hall effect in Cu doped Bi2Te3 topological insulator

The angle resolved photo-emission spectroscopy (ARPES) study and magneto-transport properties of Bi2Cu x Te3-x have been investigated. ARPES study indicates the clear existence of surface states in the as-prepared samples. The estimated bandgap from ARPES is found to be ∼5 meV and 16 meV respectively for x = 0.03 and x = 0.15 samples. Presence of larger Cu concentration (x = 0.15) introduces magnetic ordering. Observed non-linearity in the Hall data is due to the existence of anomalous Hall effect which can be attributed to the 2D transport. The observed magneto-transport features might be related to the surface carriers which is confirmed by ARPES study.

Effect of band bending on topological surface transport of Bi2Te3 single crystal

Understanding the effect of surface to bulk coupling on topological surface states is important for harnessing the topological insulators for low dissipation electronics and quantum technologies. Here we investigate this effect on a low bulk carrier density Bi₂Te₃ single crystal using magnetoresistance, Hall resistivity, and Shubnikov-de Haas oscillations. Our results show the presence of high mobility surface bands and low mobility bulk bands. The surface states exhibit ambipolar transport without any gating. The mobility of surface states strongly depend on the nature of band bending, the upward band bending with holes as surface charge carrier exhibit large mobility while the downward band bending with electrons as surface charge carriers exhibit low surface mobility. The large mobility of surface Dirac holes is related to low surface defect density and small cyclotron mass. We also observe large magnetoresistance ∼285% due to multichannel quantum coherent transport in the bulk.

A171 MAGNETIC RESONANCE IMAGING IN CHILDREN WITH EARLY ONSET INFLAMMATORY BOWEL DISEASE- A RETROSPECTIVE COHORT STUDY

Background

Magnetic Resonance (MR) Imaging is the preferred imaging method in Inflammatory Bowel Disease (IBD) patients to investigate for small bowel disease. There are challenges in performing MR imaging in Early Onset IBD (EO-IBD) patients, and in particular in children with Very Early Onset IBD (VEO-IBD). These children often need a general anaesthetic which exposes them to adverse effects and preclude conventional luminal distention influencing the quality of the test. Therefore, the utility of MR imaging in this age group is questionable.

Aims

To assess the quality of MRI studies in VEO-IBD and EO-IBD patients and to compare the utility of this test between the two groups.

Methods

We retrospectively identified and reviewed IBD patients diagnosed under 10 years of age, between January 1999 and December 2011, from the British Columbia Children’s Hospital (BCCH) GI Division IBD database. Patients’ first diagnostic MRI results were recorded. Disease location and severity were documented according to the Paris classification.

Results

124 patients were included in the cohort, 54 VEO-IBD and 70 EO-IBD patients (See Table 1). Median age at diagnosis was 6.46 (IQR 3.94–8.71), 65.32% males and 43.54% were diagnosed with Crohn’s disease. Overall, 52 patients underwent MRI, 17 (31.48%) in the VEO-IBD group and 35 (50%) in the EO-IBD group; median time from diagnosis to MRI was 3.02 years (IQR 1.08–5.83) for VEO-IBD and 0.44 years (IQR 0.07–1.58) for EO-IBD (p<0.001). In the EO-IBD group there was a significantly higher percentage of patients with MRI findings than in the VEO-IBD group, 23 (67.31%) and 5 (29.41%) respectively (p=0.014). Only one patient in the VEO-IBD group had a disease characteristic identified by MR imaging that could not be diagnosed by endoscopy (small bowel disease).

Conclusions

The diagnostic yield of MRI in children with VEO-IBD appears to be quite limited but requires further study.

Funding Agencies

None

Unusual Conductance Fluctuations and Quantum Oscillation in Mesoscopic Topological Insulator PbBi4Te7

We present a detail study of Shubinikov-de-Haas (SdH) oscillations accompanied by conductance fluctuations in a mesoscopic topological insulator PbBi₄Te₇ device. From SdH oscillations, the evidence of Dirac fermions with π Berry phase is found and the experimentally determined two main Fermi wave vectors are correlated to two surface Dirac cones (buried one inside the other) of layered topological insulator PbBi₄Te₇. We have also found evidence of conductance fluctuations, the root mean square amplitude of which is much higher than the usual universal conductance fluctuations observed in nanometer size sample. Calculated autocorrelation functions indicate periodic unique fluctuations may be associated with the topological surface states in the compound.

Magnetotransport studies of optimally doped Sr(Fe1-x Co x )2As2

We report magnetotransport measurements and their scaling analysis for the optimally electron-doped Sr(Fe_0.88Co[Formula: see text]As₂ system. We observe that both the Kohler's and modified Kohler's scalings are violated. Interestingly, the Hall angle displays a quadratic temperature dependence (cot[Formula: see text] [Formula: see text] T ²) similar to many cuprates and heavy fermion systems. The fact that this T ² dependence is seen in spite of the violation of modified Kohler's scaling suggests that the Hall angle and magnetoresistance are not governed by the same scattering mechanism. We also observe a linear magnetoresistance in this system, which does not harbor a spin density wave ground state. Implications of our observations are discussed in the context of existing models for the magnetotransport of these strongly correlated electron systems.

Thermoelectric properties of Ag-doped CuS nanocomposites synthesized by a facile polyol method

Single crystalline hexagonal nanodisks (NDs) of covellite CuS and temperature dependent thermoelectric figure of merit of Ag-doped CuS nanocomposites.

Role of lattice inhomogeneities on the electronic properties of selenium deficient Bi2Se3

Inter-layer coupling is widely considered to play a crucial role in tuning electronic properties of 3D topological insulators. The aim of this study is to evaluate the role of crystallographic defects on inter-layer coupling in the Se deficient Bi₂Se₃ (0 0 3) crystal using extended x-ray absorption fine structure spectroscopy (EXAFS) technique. EXAFS measurements at Se-K and Bi-L₃ edges reveal distinct local geometry around these atomic sites. It has been observed that short inter-layer Bi-Se and Se-Se bonds emerge in the sample. This additional structural motif coexists with the conventional crystallographic arrangement. Within the quintuple layer Bi-Se bonds are preserved with slight compression in intra-planer Bi-Bi and Se-Se distance and overall reduction in c/a ratio. These findings suggest formation of deformed lattice region, localized and dispersed inhomogeneously within the sample. Such inhomogeneities have also resulted in interesting transport properties such as quantum Hall effect (QHE), large linear magnetoresistance and π-Berry phase in Shubnikov-de Haas (SdH) oscillations of bulk crystals. Detailed analyses of magnetotransport measurements suggest that tuning of inter-layer coupling by local lattice deformation is the key factor for unusual transport properties. Role of axial strain, and stacking faults generated due to defects and charged Se vacancies are discussed to understand the observed electronic properties.

Large power factor and anomalous Hall effect and their correlation with observed linear magneto resistance in Co-doped Bi2Se3 3D topological insulator

Magnetoresistance (MR), thermo power, magnetization and Hall effect measurements have been performed on Co-doped Bi2Se3 topological insulators. The undoped sample shows that the maximum MR as a destructive interference due to a π-Berry phase leads to a decrease of MR. As the Co is doped, the linearity in MR is increased. The observed MR of Bi2Se3 can be explained with the classical model. The low temperature MR behavior of Co doped samples cannot be explained with the same model, but can be explained with the quantum linear MR model. Magnetization behavior indicates the establishment of ferromagnetic ordering with Co doping. Hall effect data also supports the establishment of ferromagnetic ordering in Co-doped Bi2Se3 samples by showing the anomalous Hall effect. Furthermore, when spectral weight suppression is insignificant, Bi2Se3 behaves as a dilute magnetic semiconductor. Moreover, the maximum power factor is observed when time reversal symmetry (TRS) is maintained. As the TRS is broken the power factor value is decreased, which indicates that with the rise of Dirac cone above the Fermi level the anomalous Hall effect and linearity in MR increase and the power factor decreases.

They [do more than] Interrupt Us from Sadness: Exploring the impact of participatory music making on social determinants of health and wellbeing for refugees in Australia

This paper reports on the outcomes of an exploratory narrative study on the impact of participatory music making on social determinants of health (SDOH) and wellbeing for refugees in Brisbane, Australia. A key component of this exploratory research was to map health and wellbeing outcomes of music participation using an existing SDOH framework developed by researchers in the field of health promotion (Schulz & Northridge, 2004). This paper maps reported health and wellbeing outcomes for five refugee and asylum seeker members of a participatory Brisbane-based music initiative, the Scattered People, along an SDOH continuum ranging from individual level through to macro level fundamental determinants of health.While most themes emerging from this study corresponded to distinct categories in the Schulz and Northridge SDOH framework, three key aspects, which were critical to the achievement of wellbeing for participants, did not fit any of the pre-defined categories. These were: cultural expression, music making, and consolidation of personal and social identity. The importance of those themes to participants suggests that music and wellbeing studies involving culturally diverse groups and from a SDOH perspective may need to consider broader, more relevant concepts. The paper provides recommendations for future interdisciplinary research in this field. 

Clodronate exerts an anabolic effect on articular chondrocytes mediated through the purinergic receptor pathway

OBJECTIVE

Bisphosphonates are commonly used anti-osteoporotic drugs which have controversial effects on joint diseases including osteoarthritis. Certain bisphosphonates have been shown to have anabolic effects on cartilage which could have important ramifications for their proposed effects in vivo; however, the underlying mechanisms are poorly understood. Thus, the purpose of this study was to characterize the effects of clodronate on primary articular chondrocyte metabolism and to determine the underlying signaling pathways responsible.

DESIGN

The effects of clodronate and pamidronate on extracellular matrix (ECM) biosynthesis, accumulation and MMP-13 activity were observed in high density, 3D cultures of bovine articular chondrocytes for up to 4 weeks were evaluated. Mechanisms were delineated by measuring intracellular Ca(2+) signaling and the effects of pharmacologic inhibition of the purinergic receptor pathway.

RESULTS

Clodronate (100 μM) induced an anabolic effect (increased biosynthesis by 13-14%) which resulted in an 89-90% increase in ECM accumulation after 4 weeks of culture and without an associated effect on matrix turn-over. Stimulation by clodronate resulted in a 3.3-fold increase in Ca(2+) signaling and pharmacological inhibitor experiments suggested that the anabolic effects exerted by clodronate are transduced through the purinergic receptor pathway.

CONCLUSIONS

These findings support the previous notion that certain bisphosphonates may be useful as adjunctive therapies to potentially ameliorate progression of cartilage degeneration and improve arthritis management.

Abstract PD10-02: Metabolic syndrome and recurrence within the 21-gene recurrence score assay risk categories in lymph node negative breast cancer

Background: The incidence of the metabolic syndrome (MS) has been increasing in the United States and elsewhere. The interaction of MS with breast cancer (BC) incidence, tumor biology and outcomes are under study. We hypothesized that the presence of MS would predict BC recurrence to a variable degree across the diverse BC biology as defined by the risk categories of the 21-gene recurrence score (RS) assay.

Patients and Methods: We studied consecutive patients (pts) with newly diagnosed, estrogen receptor (ER) positive, lymph node (LN) negative BC treated in our institution between 2006–2011 who had a 21-gene RS assay done on their tumors. All pts were treated with standard systemic and local therapy. The electronic medical record was queried for key diagnoses including MS and its constituent parts. The WHO definition was used to categorize pts as having MS defined as diabetes mellitus (DM) or glucose intolerance, plus at least 2 of the following: hypertension (HTN), dyslipidemia (HL), central obesity and microalbuminemia. Tumor characteristics including Ki67 index, grade, tumor size, HER2/neu status; and pt characteristics including age, race, menopausal status, body mass index were recorded. The association of MS and the tumor and patient characteristics with the RS tertiles of low, intermediate and high risk was analyzed.

Results: We identified 332 pts, median age 62 years, of whom 88 (27%) had MS. There was no significant association between the MS and any of the patient or tumor variables including the 21-gene RS assay, except for race (p = 0.004). Eleven of 21 (52%) African-American women had MS, 68 of 284 (24%) Caucasian women had MS, and 9 of 21 (43%) others including Hispanic and Asian women had MS. However, there was a significant association between recurrence and MS (p = 0.0002) independent of other factors. Of the 21 pts who recurred, 13 (61.9%) had MS. There was an association of recurrence and MS within RS tertiles. For pts with low risk scores, 7/44 (15.9%) with MS vs. 1/126 (0.79%) without MS had recurrence (p = 0.0003). For pts with intermediate risk scores, 5/30 (16.67%) with MS vs. 4/83 (4.82%) without MS had recurrence (p = 0.05). For patients with high risk scores, 1/9 (11.11%) with MS vs. 2/15 (13.33%) without MS had recurrence (p = 1).

Conclusion: MS is an independent risk factor for BC recurrence among women with LN negative, ER positive BC treated with standard adjuvant therapy. There is a striking impact of MS on recurrence in pts with tumor biologies defined by low (and to a lesser degree) intermediate risk 21-gene RS assay scores. However, there is no difference in recurrence risk by MS among those pts with high RS. This implies that interventions directed at modifying MS in newly diagnosed pts with early BC may potentially favorably impact survival in those with specific tumor biologies as defined by multigene assays. Thus, long-term prospective studies should be conducted to further evaluate both the short and long term effects of MS on BC outcomes.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr PD10-02.

Magnetic glass in shape memory alloy: Ni45Co5Mn38Sn12

The first order martensitic transition in the ferromagnetic shape memory alloy Ni(45)Co(5)Mn(38)Sn(12) is also a magnetic transition and has a large field induced effect. While cooling in the presence of a field this first order magnetic martensite transition is kinetically arrested. Depending on the cooling field, a fraction of the arrested ferromagnetic austenite phase persists down to the lowest temperature as a magnetic glassy state, similar to the one observed in various intermetallic alloys and in half doped manganites. A detailed investigation of this first order ferromagnetic austenite (FM-A) to low magnetization martensite (LM-M) state transition as a function of temperature and field has been carried out by magnetization measurements. Extensive cooling and heating in unequal field (CHUF) measurements and a novel field cooled protocol for isothermal MH measurements (FC-MH) are utilized to investigate the glass like arrested states and show a reverse martensite transition. Finally, we determine a field-temperature (HT) phase diagram of Ni(45)Co(5)Mn(38)Sn(12) from various magnetization measurements which brings out the regions where thermodynamic and metastable states coexist in the HT space, clearly depicting this system as a 'magnetic glass'.

Field dependence of temperature induced irreversible transformations of magnetic phases in Pr(0.5)Ca(0.5)Mn(0.975)Al(0.025)O(3) crystalline oxide

Glass-like arrest has recently been reported in various magnetic materials. As in structural glasses, the kinetics of a first order transformation is arrested while retaining the higher entropy phase as a non-ergodic state. We show visual mesoscopic evidence of the irreversible transformation of the arrested antiferromagnetic-insulating phase in Pr(0.5)Ca(0.5)Mn(0.975)Al(0.025)O(3) to its equilibrium ferromagnetic-metallic phase with an isothermal increase of magnetic field, similar to its iso-field transformation on warming. The magnetic field dependence of the non-equilibrium to equilibrium transformation temperature is shown to be governed by Le Chatelier's principle.

Simple and precise thermoelectric power measurement setup for different environments

We report here on a simple but precise thermoelectric power measurement setup that can be adapted for different environments. This setup has been extensively used for cryogen-free environment to measure a variety of samples. It is made simple to load and hold the sample between two copper blocks by a spring-shaft arrangement. The usable range of measurements is a few microV/K to a few hundreds of microV/K. The salient features of the setup in achieving good precision both in natural warm-up/cooldown and controlled measurements are (i) the continuous DeltaT control across the sample by a chromel-AuFe(0.07%) thermocouple and (ii) the measurements of emf generated across the sample and the thermocouple using a nanovoltmeter and a scanner system. The versatile nature of the setup is further demonstrated by employing it in a magnetic field environment up to 140 kOe. The precision achieved using this system is highlighted for a few systems of current interest.

Assessment of the potential for soil acidification in North India using the critical load approach and locally derived data for acidic and basic inputs

Major ions (Cl-, NO3(-), SO4(2-), Ca2+, Mg2+, Na+, K+ and NH4(+)) were analysed in wet and dry deposition samples collected for 2 years using a polyethylene bottle and funnel collector at Agra in India. The deposition of ionic components (Ca2+ and Mg2+) derived from natural sources i.e. soil were higher than those of anthropogenic origin. In rainwater samples, non-sea-salt fraction was found to be 60-90%. In both wet and dry deposition Ca2+ was found to be the dominant ion which may be due to its large particle diameter. Results suggest that most of the acidity, which occurs due to NO3(-), SO4(2-) and Cl- is neutralized by alkaline constituents, which originate from airborne local soil and dust transported from the Thar desert. Acid neutralizing capacity of soil has also been quantified and found to be 33 x 10(3) neqg(-1). Using deposition data, the critical load for acidity of soil with respect to Ashoka and Eucalyptus was evaluated. The present level of deposition of S and N was found to be much lower than critical loads calculated for S and N. Critical load of exceedance in terms of deposition acidity was also calculated and found to be negative. This indicates that with respect to these species, the ecosystem is protected at the current level of deposition.

Viral hemorrhagic fever in Pakistan: awareness among health care personnel

OBJECTIVE

To assess the level of knowledge regarding viral hemorrhagic fever (VHF) among healthcare personnel at two largest tertiary care hospitals in Karachi, Pakistan.

METHODS

A cross sectional convenience survey was conducted in February 2001 among doctors, nurses, laboratory technicians and janitors/orderlies of Jinnah Postgraduate Medical Centre and Civil Hospital, Karachi. The questionnaire included demographic information with their designation and knowledge level regarding VHF management, spread and prevention. Frequencies of the answers to each question were calculated for all questions and scores were assigned. The frequencies were also calculated on the basis of the designation of the respondent so that each group could be examined separately.

RESULTS

A total of 187 healthcare personnel (121 doctors, 31 nurses, 19 laboratory technicians and 16 janitors/orderlies) were interviewed. Forty three percent (81) respondents were males and 57% (106) were females. By designation 90% doctors, 71% nurses, 32% laboratory technicians and 6% janitors knew about VHF. Only 57% doctors (69) knew the common signs and symptoms of VHF. Isolation for affected patients was suggested by 65% nurses and 6% janitors. Knowledge regarding burial procedure of dead patients was low in all groups.

CONCLUSION

Differences in knowledge of different groups is obvious but it is essential to raise the knowledge regarding VHF at all levels including the housekeeping staff. There is also a need for continuing medical education (CME) for all health care personnel for the emerging health problems in Pakistan.

Measurements of major ion concentration in settled coarse particles and aerosols at a semiarid rural site in India

Deposition rates and deposition velocities of water-soluble ions (F, Cl, NO3, SO4, NH4, Ca, Mg, Na and K) were measured at a rural site (Gopalpura, Agra). Dry deposition samples were collected throughout the year from December 1995 to August 1997, while the aerosol samples were collected only during the winter season of 1996. Surrogate technique was used to collect the dry deposition samples, while aerosol samples were collected on PTFE membrane filter. Deposition velocities (Vd) of SO4 and NO3 are < or = 0.01 m s(-1) while Ca, Mg, Na, K, NH4, F and Cl exhibit greater than 0.01 m s(-1) Equivalent concentration ratios of K/Na, Ca/Na and Mg/Na conform with the corresponding ratios of local soil, indicating the dominant contribution of local sources. Deposition rates are maximum in winter, followed by summer and monsoon. No significant differences are found in dry deposition rates of all ions or in atmospheric concentrations of soil-derived elements with respect to wind direction. However, in aerosols, concentrations of F, Cl, NO3 and SO4 are higher with winds from southwesterly and westerly directions corresponding to pollution sources located in these directions. Deposition data have been used to calculate the critical load of S and N for soil with respect to Triticum vulgaris. The critical load of actual acidity was found to be 622.4 eq ha(-1) year(-1) within the range of 500-1,000 eq ha(-1) year(-1) as assessed by the RAINS-Asia model for this region. The present load of S and N (77.4 and 86.4 eq ha(-1) year(-1)) was much lower than the critical load of S and N (622.4 and 2,000 eq ha(-1) year(-1)), indicating that at present there is no harmful effect on ecosystem structure and function.

Addressing semen loss concerns: towards culturally appropriate HIV/AIDS interventions in Gujarat, India

A situation analysis of sexual networking and sexual health in an industrial area of Gujarat, India, identified anxiety about masturbation and other semen loss concerns as major preoccupations among young men. This paper describes how the Deepak Charitable Trust addressed these concerns in their HIV prevention programme for young men aged 15 to 30. Flowcharts were used as participatory learning tools and to obtain data on the perceived consequences of masturbation, both before and after intervention activities. Research was also done on the relation between semen-related anxieties and sexual risk behaviour by DCT and two other NGOs among young men engaging in unsafe sexual behaviour. DCT advocates addressing masturbation and other semen loss concerns in all sexual health campaigns in South Asia, based on the magnitude of these concerns, their potential to confound syndromic management of STIs and their significance as an idiom of psychosocial distress. Masturbation and associated anxieties about sexual performance are seen as health issues and discussed as such by the programme. There is immediate identification among young men, whether or not they are already sexually active, and it provides an excellent entry point for sexual health and safer sex education. The community response to these efforts has been entirely positive.

The incidences of trisomy 8, trisomy 9 and D20S108 deletion in polycythaemia vera: an analysis of blood granulocytes using interphase fluorescence in situ hybridization

We have used interphase fluorescence in situ hybridization (IFISH) to detect trisomy 8, trisomy 9 and 20q deletion in circulating granulocytes from patients with polycythaemia vera (PV). Out of 64 PV patients, 15 (23%) exhibited an abnormality. Two patients had trisomy 9, three had trisomy 8 and 10 patients had hemizygous deletion of D20S108 (a locus in the 20q common deleted region). Aberrant nuclei ranged from 10% to 80% in these 15 cases. There was no correlation between the presence of a marker and sex, age, interval between presentation and IFISH analysis, neutrophil or platelet count or therapy. Conventional marrow cytogenetic karyotype results were available in 23 cases and there was concurrence between these and blood IFISH in 16 cases (13 normal and three with 20q/D20S108 deletion by both methods). Three patients with D20S108 deletion by IFISH were normal by previous marrow cytogenetic testing and four cases with 20q deletion by previous marrow cytogenetics had normal blood granulocytes according to IFISH. Thus, we confirm that trisomies 8 and 9 and deletion of 20q are diagnostically useful markers of PV. IFISH analysis of blood granulocytes is a practical method for detecting these markers, but as an adjunct to, not as a substitute for, conventional marrow cytogenetics.

Prospective cohort study to determine if trial efficacy of anticoagulation for stroke prevention in atrial fibrillation translates into clinical effectiveness

OBJECTIVE

To determine whether trial efficacy of prophylaxis with warfarin for patients with atrial fibrillation at high risk of stroke translates into effectiveness in clinical practice.

DESIGN

Two year prospective cohort study.

SETTING

District general hospital.

PARTICIPANTS

167 patients with atrial fibrillation and at high stroke risk who were eligible for anticoagulation.

INTERVENTIONS

Long term anticoagulation with warfarin at adjusted doses to maintain an international normalised ratio of 2.0-3.0.

MAIN OUTCOME MEASURES

Comparison of patient characteristics, comorbidity, anticoagulation control, stroke rate, and haemorrhagic complications with pooled data from five randomised controlled trials.

RESULTS

Patients in the study group were seven years older (95% confidence interval 4 to 10) and comprised 33% more women than patients in the pooled trials. The international normalised ratio was in the target range for 61% of the time (range 37%-85%), below for 26% of the time (range 8%-32%), and above for 13% of the time (range 6%-26%). The time that patients in the study group spent in the target range was significantly less than in the pooled analysis. The incidence of stroke in the study group (2.0% per year, 0.7% to 4. 4%) was comparable to that of patients receiving warfarin in pooled studies (1.4%, 0.8% to 2.3%). Per year the incidence of major (1.7% v 1.6%) and minor (5.4% v 9.2%) bleeding complications was also similar.

CONCLUSION

Rates of stroke and major haemorrhage after anticoagulation in clinical practice were comparable to those obtained from pooled data from randomised controlled studies for patients with atrial fibrillation at high risk of stroke.

Intravesicular instillation of E-aminocaproic acid for patients with adenovirus-induced hemorrhagic cystitis

Hemorrhagic cystitis (HC) is a known complication of allogenic BMT. We report a case of a 28-year-old female with CML in chronic phase, which was treated with a matched unrelated donor (MUD) transplant, complicated by hemorrhagic cystitis on day +42 after the transplant. Adenovirus was isolated from the urine and she was treated with ribavirin, 1 g twice a day for 8 days. We report the use of Amicar (E-aminocaproic acid), 2.5 g solution as bladder instillation to treat the intractable hematuria.

Issues that influence patient/physician discussion of complementary therapies

This article explores what patients expect from physicians when discussing complementary therapies. Counsellors at four cancer centres, under the auspices of the British Columbia Cancer Agency, discuss their clinical observations in working with oncology patients. They present perspectives of factors that influence the patient/physician discussion of complementary therapies. Some of the common themes include desire for collaboration and control, need for understanding treatment information, maintenance of hope, and trust of the physician.

The use of intravenous intermediate dose melphalan and dexamethasone as induction treatment in the management of de novo multiple myeloma

The variable absorption of melphalan from the gastrointestinal tract results in response rates between 40 and 60%. High dose melphalan increases response rates but at the cost of increased morbidity and mortality. We have investigated intravenous intermediate dose melphalan and dexamethasone in the treatment of patients presenting with de novo multiple myeloma with the object of reducing toxicity while preserving an improved response rate compared to oral melphalan and prednisolone. The results show that this treatment can be delivered safely on an outpatient basis in patients up to the age of 78 yr; 82% of patients achieved an objective response and 30% a complete haematological and clinical remission. Median overall survival for the whole group is 37 months.

Rapid progression of fibrosing alveolitis and thyrotoxicosis after antithymocyte globulin therapy for aplastic anemia

Antithymocyte globulin (ATG) therapy is an established form of treatment for aplastic anaemia and has also been used as prophylaxis against graft rejection of bone marrow and renal allografts. Administration of ATG preparations has been associated with many mild clinical reactions, as have other forms of immunomodulatory therapy. However, serious adverse effects appear to be rare. We report a case of rapidly progressive fibrosing alveolitis and thyrotoxicosis in relation to ATG therapy, highlighting its potential toxicity and emphasising that its administration should be undertaken by experienced physicians in specialised centres.

VAPEC-B chemotherapy in the treatment of aggressive non-Hodgkin's lymphoma: a retrospective analysis of 45 patients

We performed a retrospective analysis on 45 patients who, between January 1989 and October 1993, received VAPEC-B chemotherapy for high and intermediate grade non-Hodgkin's lymphoma. The aim was to assess response and tolerance to treatment. The weekly regimen consisted of: doxorubicin 35 mg/m2 i.v. weeks 1,3,5,7,9,11; cyclophosphamide 350 mg/m2 i.v. weeks 1, 5, 9; etoposide 100 mg/m2 p.o. daily for 5 days, weeks 3, 7, 11; vincristine 1.4 mg/m2 i.v. (2 mg max.) weeks 2, 4, 6, 8, 10; bleomycin 10 mg/m2 i.v. weeks 2, 6, 10; methotrexate 12.5 mg i.t. weeks 1, 5, 9; prednisolone 50 mg p.o. daily for 6 weeks, reduced to 25 mg daily for 6 weeks. The patients treated were aged 22-71 years, 34 (75%) had high grade (Working Formulation) non-Hodgkin's lymphoma (NHL); 11 (24%) had intermediate grade NHL; 25 had Stage III/IV disease; and 14 (31%) had marrow involvement. The majority of patients (76%) received VAPEC-B as first line chemotherapy; the remainder received it for relapsing disease. Follow-up time from completion of VAPEC-B chemotherapy ranged from 6 months to 50 months (median 25). VAPEC-B, as first line therapy, induced a complete response (CR) and partial response (PR) in 79% and 18% respectively, whilst 3% had no response to treatment. VAPEC-B used for relapsing disease produced CR and PR in 64% and 27% respectively, whilst 9% failed to respond. Six patients in PR and five patients in CR have subsequently undergone an autologous bone marrow transplant or a peripheral blood stem cell transplant. In the group who received VAPEC-B first line but did not proceed to transplant (27 patients), five relapsed (three with CNS disease who had not had CNS prophylaxis). Tolerance to treatment was measured by WHO toxicity scores. The haemoglobin (Hb) toxicity median score for all patients was grade 1 (Hb 9.5-10.9 g/dl), and the white cell count (WCC), toxicity score was grade 2 (WCC 2.0-2.9 x 10(9)/l). No platelet toxicity was observed. Ten per cent of patients suffered grade 3 severity infections requiring antibiotics and there was one treatment related death. The majority of patients received VAPEC-B on time, however, 24% patients had a 2-week delay. VAPEC-B chemotherapy is an effective regimen for malignant lymphoma, either as a first line or as a salvage treatment. Although chemotherapy was given weekly, the tolerance to treatment was acceptable, thus making this short regimen a good alternative to CHOP chemotherapy.

A pilot study of low-dose recombinant human granulocyte-macrophage colony-stimulating factor in chronic neutropenia

Recombinant human granulocyte macrophage colony stimulating factor (rhGM-CSF) is under investigation for the treatment of a wide range of haematological disorders. At commonly used doses of > 120 micrograms/m2/d, extramedullary toxicity is common. We report the effects of low-dose (LD) rhGM-CSF in patients with chronic neutropenia related to HIV infection, myelodysplastic syndrome and idiopathic neutropenia. Nine patients with a mean pre-treatment neutrophil count of 0.6 x 10(9)/l (range 0.2-1.4 x 10(9)/l) received daily rhGM-CSF at doses of between 5 and 15 micrograms/m2. Eight patients responded with a mean post-treatment ANC of 3.2 x 10(9)/l (range 1.9-4.6 x 10(9)/l). There was no significant therapy-related morbidity. We conclude that in chronic neutropenia, LD rhGM-CSF is an acceptable treatment which has important cost/benefit implications.

Deletion of the long arm of chromosome 5 in essential thrombocythemia

A 51-year-old woman with no history of prior chemotherapy or radiation therapy was diagnosed with essential thrombocythemia (ET) according to the diagnostic criteria established by the Polycythemia Vera Study Group (PVSG). Cytogenetic analysis of bone marrow metaphases revealed both normal female karyotype and a single clonal abnormality, 46,XX,del(5)(q22q35). While chromosomal abnormalities have been reported in ET, their incidence is very low, and no specific abnormality has been found. Many of the reported cases of ET with chromosomal aberrations, including 5q-, do not meet the diagnostic criteria proposed by the PVSG, and may represent one of the other myeloproliferative disorders or a myelodysplastic syndrome. Furthermore, it is important to distinguish the 5q- syndrome, which may present with thrombocytosis and megakaryocytic hyperplasia, from ET. Our patient appears to be the first example of untreated ET clearly meeting the PVSG criteria in which 5q- was the only clonal abnormality seen at diagnosis.

Legionnaires' disease and the sick-building syndrome

In October 1985, six cases of legionnaires' disease were associated with a police headquarters building. Four were amongst staff who worked in or visited the communications wing of the headquarters and two cases occurred in the local community. A case-control study implicated the operations room of the communications wing as the main area associated with infection. This wing was air-conditioned and smoke tracer studies showed that drift from the exhaust as well as from the base of the cooling tower entered the main air-intake which serviced the air-conditioning system. Legionella pneumophila serogroup 1 subgroup pontiac was isolated from water and sludge in the cooling tower pond. Contaminated drift from the top of the cooling tower was probably responsible for the two community cases. An additional discovery was that symptoms suggestive of the sick-building syndrome were associated with working in this wing.

Treatment of relapsed and refractory acute leukaemia with high-dose cytosine arabinoside and etoposide

A total of 65 patients under the age of 55 with acute leukaemia received high-dose cytosine arabinoside (Ara-C) in combination with high-dose etoposide without an anthracycline. Complete remission rates for patients with relapsed or refractory acute myelogenous leukaemia (AML) were 15/25 (60%) and 11/16 (69%), respectively. The complete remission rate for patients with refractory or relapsed acute lymphoblastic leukaemia (ALL) was 10/18 (56%). The treatment-related mortality was 17%. Nine patients whose leukaemia relapsed after matched allogeneic, sibling bone-marrow transplantation (BMT) were also treated in this way; the treatment-related mortality in this group was high (7/9) and the duration of remission in the two patients who responded, too short to justify this intensive treatment in such patients. Similarly, patients who underwent BMT after achieving a complete remission with high-dose Ara-C and etoposide did very poorly, only one patient surviving well and disease-free at 8 months. The important finding in this study was the high complete remission rate rapidly obtained in patients with relapsed or refractory AML without using an anthracycline.