Role of selenium addition to CdZnTe matrix for room-temperature radiation detector applications

Because of its ideal band gap, high density and high electron mobility-lifetime product, cadmium zinc telluride (CdZnTe or CZT) is currently the best room-temperature compound-semiconductor X- and gamma-ray detector material. However, because of its innate poor thermo-physical properties and above unity segregation coefficient for Zn, the wide spread deployment of this material in large-volume CZT detectors is still limited by the high production cost. The underlying reason for the low yield of high-quality material is that CZT suffers from three major detrimental defects: compositional inhomogeneity, high concentrations of dislocation walls/sub-grain boundary networks and high concentrations of Te inclusions/precipitates. To mitigate all these disadvantages, we report for the first time the effects of the addition of selenium to the CZT matrix. The addition of Se was found to be very effective in arresting the formation of sub-grain boundaries and its networks, significantly reducing Zn segregation, improving compositional homogeneity and resulting in much lower concentrations of Te inclusions/precipitates. Growth of the new quaternary crystal Cd_1−xZn_xTe_1−ySe_y (CZTS) by the Traveling Heater Method (THM) is reported in this paper. We have demonstrated the production of much higher yield according to its compositional homogeneity, with substantially lower sub-grain boundaries and their network, and a lower concentration of Te inclusions/precipitates.

Pattern of Casualties Attending in the Casualty Department of Mymensingh Medical College Hospital, Mymensingh, Bangladesh

Casualty, in relation to personnel, any person who is lost to his organization; by reason of being declared dead, wounded, diseased, detained, captured or missing. Casualty service or department is not well organized in the hospitals of our country. We have recently started functioning casualty department to manage casualties properly in spite of the increasing workload and emerging needs of this department. This study was conducted in the Casualty department, Mymensingh Medical College Hospital (MMCH), Mymensingh, Bangladesh to analyze the number of patients and pattern of casualties. A total number of 17435 patients were enrolled in this retrospective observational study. Data was collected from hospital records of all patients attending in the Casualty Department, MMCH between November 19, 2017 and May 18, 2018 and patients were categorized on the basis of their mode of injury. The demographic characteristics of patients with mode of Casualty were analyzed. Male were 75% and female 25%. Avergae per day patient attended in the Casualty department was 96, maximum was 176 and minimum 33. According to age sub-division, 11-20 years age group attended maxiumum was 48. One day attended Road traffic accident (RTA) maximum was 65 and minimum was 3, Non-RTA maximum was 83 and minimum 25, physical assaults maximum was 48 and minimum 1. Injury due to fall and RTA were the common mode of casualty especially in the young population in the study area. Study showed that injury caused by fall was 44% among the all patients. Patients due to fall from tree was highest (35%) in April-May. Incidents of fall were followed by RTA which was 25%. Physical assaults (17%), machinery injury (9%) and others were 5%.

In vitro cytotoxicity and antibiotic application of green route surface modified ferromagnetic TiO2 nanoparticles

The enormous numbers of applications of TiO₂ nanoparticles (NPs) cause concern about their risk to the environment and human health. Consequently, motivated by the necessity of searching for new sources of TiO₂ NPs of low cytotoxicity with antibacterial activity, we synthesized TiO₂ NPs by a green route using a solution of titanium(iv) isopropoxide as a precursor and an aqueous extract of Artocarpus heterophyllus leaf as a reducing and surface modifying agent. We investigated their structure, shape, size, and magnetic properties, and evaluated their antibiotic application and cytotoxicity. The synthesized TiO₂ NPs were applied against two Gram-negative bacteria (E. coli and S. typhimurium) and two Gram-positive bacteria (S. aureus and B. subtilis) to observe their antibacterial activity; and eventually clear zones of inhibition formed by the TiO₂ NPs were obtained. Moreover, after exposing the synthesized TiO₂ NPs to HeLa cells (carcinoma cells) and Vero cells (normal cells), no toxic effect was found up to a dose of 1000 mg L⁻¹, indicating the safe use of the samples up to at least 1000 mg L⁻¹. However, toxic effects on HeLa cells and Vero cells were observed at doses of 2000 mg L⁻¹ and 3000 mg L⁻¹, respectively. These results indicate the safe use of Artocarpus heterophyllus leaf extract mediated synthesized TiO₂ NPs in their potential applications.

Artocarpus heterophyllus leaf extract mediated green synthesized TiO₂ nanoparticles exhibit less toxicity with high antibacterial activity.

Investigation of methicillin-resistant Staphylococcus aureus among clinical isolates from humans and animals by culture methods and multiplex PCR

Background

Staphylococcus aureus is responsible for large numbers of hospital-related and community-acquired infections. In this study, we investigated the presence of S. aureus and methicillin-resistant S. aureus (MRSA) in 100 samples from animals (55 cattle, 36 dogs, and 9 cats) and 150 samples from hospitalized human patients. The samples were collected from healthy and diseased animals and from diseased humans and included milk, wound swab, pus, exudates, nasal swab and diabetic ulcer. Initially, S. aureus was isolated and identified by colony morphology, Gram staining, and biochemical tests (catalase and coagulase tests). The S. aureus-positive samples were examined by polymerase chain reaction (PCR) to determine their MRSA status.

Results

Of the 100 animal samples, 29 were positive for S. aureus. Four samples (13.8%) from dogs were MRSA-positive, but samples from cattle and cats were MRSA-negative. Of the 150 human samples we collected, 64 were S. aureus-positive and, of these, 34 (53.1%) were MRSA-positive. Most (28%) of the MRSA samples were isolated from surgical wound swabs, followed by the pus from skin infections (11%), exudates from diabetic ulcers (6%), exudates from burns (4%), and aural swabs (3%). By contrast, a low MRSA detection rate (n = 4) was seen in the non-human isolates, where all MRSA bacteria were isolated from nasal swabs from dogs. The antimicrobials susceptibility testing results showed that S. aureus isolates with mecA genes showed resistance to penicillin (100%), oxacillin (100%), erythromycin (73.5%), ciprofloxacin (70.6%), and gentamicin (67.7%). The lowest resistance was found against ceftazidime, and no vancomycin-resistant isolates were obtained.

Conclusions

We detected S. aureus and MRSA in both human and canine specimens. Isolates were found to be resistant to some of the antimicrobials available locally. MRSA carriage in humans and animals appears to be a great threat to effective antimicrobials treatment. The prudent use of antimicrobials will reduce the antimicrobial resistance. Our findings will help to find the most appropriate treatment and to reduce antimicrobial resistance in the future by implementing prudent use of antimicrobials. Further studies are required to better understand the epidemiology of MRSA human–animal inter-species transmission in Bangladesh.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1611-0) contains supplementary material, which is available to authorized users.

Halotolerant bacteria belonging to operational group Bacillus amyloliquefaciens in biocontrol of the rice brown stripe pathogen Acidovorax oryzae

AIMS

The aim of this study was to evaluate the antagonistic activity of halotolerant bacteria against rice brown stripe pathogen Acidovorax oryzae.

METHODS AND RESULTS

Fifteen of 136 isolates of halotolerant bacteria exhibited strong in vitro and in vivo antagonistic activity against both strains of A. oryzae. The 15 antagonistic isolates were identified as 'operational group Bacillus amyloliquefaciens' based on physiological and biochemical features, fatty acid profiles as well as sequence analysis of 16S rRNA, gyrA and rpoB genes. Furthermore, this result indicated that the most effective antagonistic isolates K5-3 and PPB6 could produce siderophore in iron-limiting medium, and four kinds of secondary metabolites based on MALDI-TOF analysis. In addition, the culture filtrates of isolates K5-3 and PPB6 caused the damage of cell membrane evidenced by the TEM images, and resulted in 73-80% reduction in cell numbers, 55-65% reduction in biofilm formation, and 42-50% reduction in swimming ability of both strains of A. oryzae.

CONCLUSIONS

These isolates in particular K5-3 and PPB6 of halotolerant bacteria markedly inhibited the growth of A. oryzae.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, this is the first report on biological control of halotolerant bacteria against bacterial brown stripe of rice.

Ethnic variation in personality disorder: evaluation of 6 years of hospital admissions

Aims and methodThere is limited evidence on ethnic differences in personality disorder prevalence rates. We compared rates of people with personality disorder admitted to hospital in East London from 2007 to 2013.

RESULTS

Of all people admitted to hospital, 9.7% had a personality disorder diagnosis. The admission rate for personality disorder has increased each year. Compared with White subjects, personality disorder was significantly less prevalent among Black and other minority ethnic (BME) groups. Personality disorder was diagnosed in 20% of forensic, 11% of general adult, 8% of adolescent and 2% of old-age in-patients.Clinical implicationsThe increasing number of personality disorder diagnoses year on year indicates the increasing impact of personality disorder on in-patient services. It is important to identify and appropriately manage patients with a personality disorder diagnosis due to the significant strain they place on resources. The reasons for fewer admissions of BME patients may reflect alternative service use, a truly lower prevalence rate or under-detection.Declaration of interestNone.

Can Bangladesh produce enough cereals to meet future demand?

Bangladesh faces huge challenges in achieving food security due to its high population, diet changes, and limited room for expanding cropland and cropping intensity. The objective of this study is to assess the degree to which Bangladesh can be self-sufficient in terms of domestic maize, rice and wheat production by the years 2030 and 2050 by closing the existing gap (Yg) between yield potential (Yp) and actual farm yield (Ya), accounting for possible changes in cropland area. Yield potential and yield gaps were calculated for the three crops using well-validated crop models and site-specific weather, management and soil data, and upscaled to the whole country. We assessed potential grain production in the years 2030 and 2050 for six land use change scenarios (general decrease in arable land; declining ground water tables in the north; cropping of fallow areas in the south; effect of sea level rise; increased cropping intensity; and larger share of cash crops) and three levels of Yg closure (1: no yield increase; 2: Yg closure at a level equivalent to 50% (50% Yg closure); 3: Yg closure to a level of 85% of Yp (irrigated crops) and 80% of water-limited yield potential or Yw (rainfed crops) (full Yg closure)). In addition, changes in demand with low and high population growth rates, and substitution of rice by maize in future diets were also examined. Total aggregated demand of the three cereals (in milled rice equivalents) in 2030 and 2050, based on the UN median population variant, is projected to be 21 and 24% higher than in 2010. Current Yg represent 50% (irrigated rice), 48-63% (rainfed rice), 49% (irrigated wheat), 40% (rainfed wheat), 46% (irrigated maize), and 44% (rainfed maize) of their Yp or Yw. With 50% Yg closure and for various land use changes, self-sufficiency ratio will be > 1 for rice in 2030 and about one in 2050 but well below one for maize and wheat in both 2030 and 2050. With full Yg closure, self-sufficiency ratios will be well above one for rice and all three cereals jointly but below one for maize and wheat for all scenarios, except for the scenario with drastic decrease in boro rice area to allow for area expansion for cash crops. Full Yg closure of all cereals is needed to compensate for area decreases and demand increases, and then even some maize and large amounts of wheat imports will be required to satisfy demand in future. The results of this analysis have important implications for Bangladesh and other countries with high population growth rate, shrinking arable land due to rapid urbanization, and highly vulnerable to climate change.

Green synthesis of bio-molecule encapsulated magnetic silver nanoparticles and their antibacterial activity

Persuaded by the necessity of finding new sources of antibiotics, silver nanoparticles (Ag NPs) were synthesized by adopting a newly developed green synthesis technique and subsequently, their antibacterial activity against different pathogenic bacteria was evaluated. We have successfully synthesized bio-molecule capped ferromagnetic Ag NPs with an average crystallite size of 13 nm using AgNO₃ solution as a precursor and Artocarpus heterophyllus leaf extract as a reducing and capping agent. The characterization of the synthesized Ag NPs was carried out using various techniques such as UV-visible (UV-Vis) spectroscopy, energy dispersive X-ray (EDX) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetry (TG), and vibrating sample magnetometer (VSM) analyses. After exposing the synthesized Ag NPs to two Gram-positive bacteria – Staphylococcus aureus and Bacillus cereus and two Gram-negative bacteria – Escherichia coli and Salmonella typhimurium, the zones of inhibition were found to be 15, 16, 19, and 18 mm, respectively. These results imply that the Artocarpus heterophyllus leaf extract mediated green synthesized bio-molecules encapsulated Ag NPs can be considered as a potential antibiotic against human pathogens which is very encouraging.

Persuaded by the necessity of finding new sources of antibiotics, Ag NPs were synthesized by adopting a newly developed green synthesis technique and subsequently, their antibacterial activity against different pathogenic bacteria was evaluated.

Anthropogenic shift of planktonic food web structure in a coastal lagoon by freshwater flow regulation

Anthropogenic modification of aquatic systems has diverse impacts on food web interactions and ecosystem states. To reverse the adverse effects of modified freshwater flow, adequate management of discharge is required, especially due to higher water requirements and abstractions for human use. Here, we look at the effects of anthropogenically controlled freshwater flow regimes on the planktonic food web of a Ramsar listed coastal lagoon that is under recovery from degradation. Our results show shifts in water quality and plankton community interactions associated to changes in water flow. These shifts in food web interactions represent modifications in habitat complexity and water quality. At high flow, phytoplankton-zooplankton interactions dominate the food web. Conversely, at low flow, bacteria, viruses and nano/picoplankton interactions are more dominant, with a substantial switch of the food web towards heterotrophy. This switch can be associated with excess organic matter loading, decomposition of dead organisms, and synergistic and antagonistic interactions. We suggest that a lower variability in flow amplitude could be beneficial for the long-term sustaining of water quality and food web interactions, while improving the ecosystem health of systems facing similar stresses as the Coorong.

Abstract OT2-01-07: A phase 2 study of abemaciclib plus pembrolizumab for patients with hormone receptor positive (HR+), HER2 negative (HER2-) metastatic breast cancer (MBC)

Background:

Abemaciclib is a small molecule inhibitor of both cyclin-dependent kinase (CDK) 4 and CDK6 administered orally twice daily on a continuous schedule. In I3Y-MC-JPBA, a phase I study, abemaciclib demonstrated acceptable safety, tolerability, and single-agent activity as monotherapy in different tumor types, including HR+ MBC (Patnaik A,et al. Cancer Discov 2016;6:1–14). In MONARCH 1, a phase 2 study, abemaciclib demonstrated a 19.7% objective response rate (ORR) with a median duration of response (DoR) of 8.6 months, median progression-free survival (PFS) of 6.0 months, and clinical benefit rate (CBR) of 42.4% in patients with HR+, HER2- MBC whose disease progressed on or after endocrine therapy and chemotherapy (Dickler, M. et al. American Society of Clinical Oncology (ASCO), abstract #510 (2016).). Pembrolizumab is a humanized monoclonal antibody against the programmed death receptor-1 (PD-1) protein that has shown preliminary efficacy in single-arm monotherapy trials in ER+/HER2- advanced breast cancer.

Trial design:

This open-label, phase 2 study will evaluate the safety and preliminary efficacy of abemaciclib 150 mg given orally every 12 hours on days 1-21 of a 21-day cycle in combination with intravenous pembrolizumab 200 mg on day 1 of a 21-day cycle in approximately 75 patients with stage IV non-small cell lung cancer or HR+, HER2- MBC (ClinicalTrials.gov NCT02779751). The study will include 3 disease-specific cohorts, each with approximately 25 patients. Only the HR+, HER2- MBC cohort will be presented here.

Eligibility criteria:

Eligible patients for the MBC cohort include women with confirmed HR+, HER2- MBC who have completed at least 1 but no more than 2 prior chemotherapy regimens in the metastatic setting; will provide tumor tissue prior to and after treatment (cycle 3, day 1); have measurable disease (RECIST v.1.1), adequate organ function, an ECOG performance status ≤1, and a life expectancy ≥12 weeks; are ≥18 yrs of age and able to swallow oral medications; and have not received treatment with any CDK 4 and 6 inhibitors or PD-1 or PD-L1 inhibitors.

Specific aims:

The primary objective is to characterize the safety profile of the combination of abemaciclib and pembrolizumab. Key secondary objectives include ORR, DoR, disease control rate (DCR), PFS, overall survival (OS), and characterization of pharmacokinetics.

Statistical methods:

The safety population includes patients who received at least one dose of study drug. ORR, DoR, DCR, and PFS analyses will be evaluated according to RECIST v.1.1 and irRECIST for disease progression. Time-to-event variables, such as DoR, PFS, and OS, will be estimated by Kaplan-Meier methodology. An interim analysis of safety and preliminary efficacy may occur for each cohort after all patients have completed (or discontinued from) approximately 24 weeks of treatment. The final analysis of OS will occur based on data collected for approximately 12 months after the last patient receives treatment.

Target accrual:

Approximately 75 patients are planned for the trial; 25 patients will comprise the MBC cohort.

Contact information: 1-877-CTLILLY (1-877-285-4559).

Citation Format: Rugo H, Tolaney S, Dickler M, Kabos P, Ho C-L, Wildiers H, Jerusalem G, Alés-Martínez JE, Hossain A, Johnston E, Gianni L. A phase 2 study of abemaciclib plus pembrolizumab for patients with hormone receptor positive (HR+), HER2 negative (HER2-) metastatic breast cancer (MBC) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT2-01-07.

Test of a 32-channel Prototype ASIC for Photon Counting Application

A new low-power application-specific integrated circuit (ASIC) for Cadmium Zinc Telluride (CZT) detectors for single-photon emission computed tomography (SPECT) application is being developed at BNL. As the first step, a 32-channel prototype ASIC was designed and tested recently. Each channel has a preamplifier followed by CR-RC³ shaping circuits and three independent energy bins with comparators and 16-bit counters. The ASIC was fabricated with TSMC 0.35-μm complementary metal-oxide-semiconductor (CMOS) process and tested in laboratories. The power consumption is around 1 mW/ch with a 2.5-V supply. With a gain of 400 mV/fC and the peaking time of 500 ns, the equivalent noise charge (ENC) of 360 e- has been measured in room temperature while the crosstalk rate is less than 0.3%. The 10-bit DACs for global thresholds have an integral nonlinearity (INL) less than 0.56% and differential nonlinearity (DNL) less than 0.33%. In the presentation, we will report the detailed test results with this ASIC.

Novel ZnO:Al contacts to CdZnTe for X- and gamma-ray detectors

CdZnTe (CZT) has made a significant impact as a material for room-temperature nuclear-radiation detectors due to its potential impact in applications related to nonproliferation, homeland security, medical imaging, and gamma-ray telescopes. In all such applications, common metals, such as gold, platinum and indium, have been used as electrodes for fabricating the detectors. Because of the large mismatch in the thermal-expansion coefficient between the metal contacts and CZT, the contacts can undergo stress and mechanical degradation, which is the main cause for device instability over the long term. Here, we report for the first time on our use of Al-doped ZnO as the preferred electrode for such detectors. The material was selected because of its better contact properties compared to those of the metals commonly used today. Comparisons were conducted for the detector properties using different contacts, and improvements in the performances of ZnO:Al-coated detectors are described in this paper. These studies show that Al:ZnO contacts to CZT radiation detectors offer the potential of becoming a transformative replacement for the common metallic contacts due to the dramatic improvements in the performance of detectors and improved long-term stability.

Stability of the Baseline Holder in Readout Circuits For Radiation Detectors

Baseline holder (BLH) circuits are used widely to stabilize the analog output of application-specific integrated circuits (ASICs) for high-count-rate applications. The careful design of BLH circuits is vital to the overall stability of the analog-signal-processing chain in ASICs. Recently, we observed self-triggered fluctuations in an ASIC in which the shaping circuits have a BLH circuit in the feedback loop. In fact, further investigations showed that methods of enhancing small-signal stabilities cause an even worse situation. To resolve this problem, we used large-signal analyses to study the circuit's stability. We found that a relatively small gain for the error amplifier and a small current in the non-linear stage of the BLH are required to enhance stability in large-signal analysis, which will compromise the properties of the BLH. These findings were verified by SPICE simulations. In this paper, we present our detailed analysis of the BLH circuits, and propose an improved version of them that have only minimal self-triggered fluctuations. We summarize the design considerations both for the stability and the properties of the BLH circuits.

Anti-tuberculosis drug resistance in Bangladesh: reflections from the first nationwide survey

OBJECTIVE

To determine the prevalence of tuberculosis (TB) drug resistance in Bangladesh.

DESIGN

Weighted cluster sampling among smear-positive cases, and standard culture and drug susceptibility testing on solid medium were used.

RESULTS

Of 1480 patients enrolled during 2011, 12 falsified multidrug-resistant TB (MDR-TB) patients were excluded. Analysis included 1340 cases (90.5% of those enrolled) with valid results and known treatment antecedents. Of 1049 new cases, 12.3% (95%CI 9.3-16.1) had strains resistant to any of the first-line drugs tested, and 1.4% (95%CI 0.7-2.5) were MDR-TB. Among the 291 previously treated cases, this was respectively 43.2% (95%CI 37.1-49.5) and 28.5% (95%CI 23.5-34.1). History of previous anti-tuberculosis treatment was the only predictive factor for first-line drug resistance (OR 34.9). Among the MDR-TB patients, 19.2% (95%CI 11.3-30.5; exclusively previously treated) also showed resistance to ofloxacin. Resistance to kanamycin was not detected.

CONCLUSION

Although MDR-TB prevalence was relatively low, transmission of MDR-TB may be increasing in Bangladesh. MDR-TB with fluoroquinolone resistance is rapidly rising. Integrating the private sector should be made high priority given the excessive proportion of MDR-TB retreatment cases in large cities. TB control programmes and donors should avoid applying undue pressure towards meeting global targets, which can lead to corruption of data even in national surveys.

An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm(3) detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays' performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

Role of crush smear cytology in the diagnosis of gastrointestinal malignancy

Crush smear cytology, commonly used for central nervous system lesions was reported to be useful in the diagnosis of GI malignancies. This study was designed to see the accuracy of crush smear cytology in detection of gastrointestinal malignancy in relation to histopathological examination. First 4 or 5 bits of pinch biopsy specimens from each of the consecutive patients having endoscopic findings suggestive of carcinoma of gastro-intestinal tract were examined by conventional paraffin embedding and H-E staining by a cytologist. Crush smears stained with Papanicolaou's stain were prepared with the last bit of specimen and were examined by another cytologist. The diagnostic accuracy was examined by correlating with clinical and histological data. Out of 100 cases of suspected oesophageal malignancies, 99 were diagnosed as carcinoma by histopathology and 84 (sensitivity 83.83%, accuracy 83%, K - 0.14) cases were positive for malignancy by crush smear cytology. Out of 60 cases of gastric lesion, 54 and 44 cases were proved to be malignant by histopathology (sensitivity 76%, accuracy 73.3%, K - 0.2) and crush smear cytology respectively. Fifty four of the 57 cases of colonic lesions were proved to be malignant by histopathology and 50 (sensitivity 91%, accuracy 89.5%, K - 0.34) were malignant by crush smear cytology. Combining two methods the accuracy was 100%, 95% and 96.5% in detecting oesophageal, gastric and colonic malignancies respectively. Concordance rate of both the methods in diagnosing oesophageal, gastric and colonic lesions were 883.83%, 73.3% and 89.5% respectively. Crush smear cytology is a cheap, easy and rapidly performing technique. The diagnostic yield is very high when the technique is combined with histopathology. It may be used as a useful adjunct to conventional histopathology.