Topological Crystalline Insulators in the SnTe Material Class

Topological crystalline insulators are new states of matter in which the topological nature of electronic structures arises from crystal symmetries. Here we predict the first material realization of topological crystalline insulator in the semiconductor SnTe, by identifying its nonzero topological index. We predict that as a manifestation of this nontrivial topology, SnTe has metallic surface states with an even number of Dirac cones on high-symmetry crystal surfaces such as {001}, {110} and {111}. These surface states form a new type of high-mobility chiral electron gas, which is robust against disorder and topologically protected by reflection symmetry of the crystal with respect to {110} mirror plane. Breaking this mirror symmetry via elastic strain engineering or applying an in-plane magnetic field can open up a continuously tunable band gap on the surface, which may lead to wide-ranging applications in thermoelectrics, infrared detection, and tunable electronics. Closely related semiconductors PbTe and PbSe also become topological crystalline insulators after band inversion by pressure, strain and alloying.Comment: submitted on Feb. 10, 2012; to appear in Nature Communications; 5 pages, 4 figure

Altered Neurocircuitry in the Dopamine Transporter Knockout Mouse Brain

The plasma membrane transporters for the monoamine neurotransmitters dopamine, serotonin, and norepinephrine modulate the dynamics of these monoamine neurotransmitters. Thus, activity of these transporters has significant consequences for monoamine activity throughout the brain and for a number of neurological and psychiatric disorders. Gene knockout (KO) mice that reduce or eliminate expression of each of these monoamine transporters have provided a wealth of new information about the function of these proteins at molecular, physiological and behavioral levels. In the present work we use the unique properties of magnetic resonance imaging (MRI) to probe the effects of altered dopaminergic dynamics on meso-scale neuronal circuitry and overall brain morphology, since changes at these levels of organization might help to account for some of the extensive pharmacological and behavioral differences observed in dopamine transporter (DAT) KO mice. Despite the smaller size of these animals, voxel-wise statistical comparison of high resolution structural MR images indicated little morphological change as a consequence of DAT KO. Likewise, proton magnetic resonance spectra recorded in the striatum indicated no significant changes in detectable metabolite concentrations between DAT KO and wild-type (WT) mice. In contrast, alterations in the circuitry from the prefrontal cortex to the mesocortical limbic system, an important brain component intimately tied to function of mesolimbic/mesocortical dopamine reward pathways, were revealed by manganese-enhanced MRI (MEMRI). Analysis of co-registered MEMRI images taken over the 26 hours after introduction of Mn^(2+) into the prefrontal cortex indicated that DAT KO mice have a truncated Mn^(2+) distribution within this circuitry with little accumulation beyond the thalamus or contralateral to the injection site. By contrast, WT littermates exhibit Mn^(2+) transport into more posterior midbrain nuclei and contralateral mesolimbic structures at 26 hr post-injection. Thus, DAT KO mice appear, at this level of anatomic resolution, to have preserved cortico-striatal-thalamic connectivity but diminished robustness of reward-modulating circuitry distal to the thalamus. This is in contradistinction to the state of this circuitry in serotonin transporter KO mice where we observed more robust connectivity in more posterior brain regions using methods identical to those employed here

Morphological Change of Dhaka City Over a Period of 55 Years: A Case Study of Two Wards

Dhaka City has undergone radical changes in its physical form, not only by territorial expansion, but also through internal physical transformations over the last decades. These have created entirely new kinds of fabric. With these changes, the elements of urban form have changed. Plots and open spaces have been transformed into building areas, open squares into car parks, low land and water bodies into reclaimed built-up lands etc. This research has its general interest in the morphologic change of Dhaka City. It focuses on the spatial dynamics of urban growth of Dhaka over the last 55 years from 1952-2007. In the research, the transformation of urban form has been examined through space syntax. The aim behind using this technique is to describe aspects of relationships between the morphological structure of man-made environments and social structures and events. To conduct this research, Wards 49 and 72 of Dhaka City Corporation were selected as the study areas, of which Ward 72 is an indigenous and Ward 49 is a planned type of settlement. Being a planned residential area, the syntactic measures from this morphological analysis are showing quite unchanged and high values in all phases for Ward 49 and the physical characteristics of Ward 72 (Old Dhaka) still represent the past. The syntactic values are found to be higher for Ward 72 and than Ward 49. Higher values indicate that the street network is highly connective among each other. Time affects differently the layout of cities and the architecture of buildings. Of the many human creations, street systems are among the most resistant to change. This has been emphasized in this study, thereby facilitating the comparison of urban layouts across space and time. The interpretation of history in the light of quantitative accounts, as demonstrated in this study, will be of value to urban planners and urban designers for the future planning of modern Dhaka City

Sustained release formulation of an anti-tuberculosis drug based on para-amino salicylic acid-zinc layered hydroxide nanocomposite

Background: Tuberculosis (TB), is caused by the bacteria, Mycobacterium tuberculosis and its a threat to humans since centuries. Depending on the type of TB, its treatment can last for 6-24 months which is a major cause for patients non-compliance and treatment failure. Many adverse effects are associated with the currently available TB medicines, and there has been no new anti-tuberculosis drug on the market for more than 50 year, as the drug development is very lengthy and budget consuming process.Development of the biocompatible nano drug delivery systems with the ability to minimize the side effects of the drugs, protection of the drug from enzymatic degradation. And most importantly the drug delivery systems which can deliver the drug at target site would increase the therapeutic efficacy. Nanovehicles with their tendency to release the drug in a sustained manner would result in the bioavalibilty of the drugs in the body for a longer period of time and this would reduce the dosing frequency in drug administration. The biocompatible nanovehicles with the properties like sustained release of drug of the target site, protection of the drug from physio-chemical degradation, reduction in dosing frequency, and prolong bioavailability of drug in the body would result in the shortening of the treatment duration. All of these factors would improve the patient compliance with chemotherapy of TB.Result: An anti-tuberculosis drug, 4-amino salicylic acid (4-ASA) was successfully intercalated into the interlamellae of zinc layered hydroxide (ZLH) via direct reaction with zinc oxide suspension. The X-ray diffraction patterns and FTIR analyses indicate that the molecule was successfully intercalated into the ZLH interlayer space with an average basal spacing of 24 Å. Furthermore, TGA and DTG results show that the drug 4-ASA is stabilized in the interlayers by electrostatic interaction. The release of 4-ASA from the nanocomposite was found to be in a sustained manner. The nanocomposite treated with normal 3T3 cells shows it reduces cell viability in a dose- and time-dependent manner.Conclusions: Sustained release formulation of the nanocomposite, 4-ASA intercalated into zinc layered hydroxides, with its ease of preparation, sustained release of the active and less-toxic to the cell is a step forward for a more patient-friendly chemotherapy of Tuberculosis

Deterministic diffusion fiber tracking improved by quantitative anisotropy

Diffusion MRI tractography has emerged as a useful and popular tool for mapping connections between brain regions. In this study, we examined the performance of quantitative anisotropy (QA) in facilitating deterministic fiber tracking. Two phantom studies were conducted. The first phantom study examined the susceptibility of fractional anisotropy (FA), generalized factional anisotropy (GFA), and QA to various partial volume effects. The second phantom study examined the spatial resolution of the FA-aided, GFA-aided, and QA-aided tractographies. An in vivo study was conducted to track the arcuate fasciculus, and two neurosurgeons blind to the acquisition and analysis settings were invited to identify false tracks. The performance of QA in assisting fiber tracking was compared with FA, GFA, and anatomical information from T 1-weighted images. Our first phantom study showed that QA is less sensitive to the partial volume effects of crossing fibers and free water, suggesting that it is a robust index. The second phantom study showed that the QA-aided tractography has better resolution than the FA-aided and GFA-aided tractography. Our in vivo study further showed that the QA-aided tractography outperforms the FA-aided, GFA-aided, and anatomy-aided tractographies. In the shell scheme (HARDI), the FA-aided, GFA-aided, and anatomy-aided tractographies have 30.7%, 32.6%, and 24.45% of the false tracks, respectively, while the QA-aided tractography has 16.2%. In the grid scheme (DSI), the FA-aided, GFA-aided, and anatomy-aided tractographies have 12.3%, 9.0%, and 10.93% of the false tracks, respectively, while the QA-aided tractography has 4.43%. The QA-aided deterministic fiber tracking may assist fiber tracking studies and facilitate the advancement of human connectomics. © 2013 Yeh et al

Pattern of Childhood Malignant Tumour in the Paediatric Surgery Department of Bangabandhu Sheikh Mujib Medical University

Background: Childhood malignancy is fast becoming an important paediatric problem in Bangladesh. They differ markedly from adult malignancy in their nature and distribution. This is a 5 years retrospective study of childhood malignant tumour as seen at the paediatric surgery department of Bangabandhu Sheikh Mujib Medical University (BSMMU). Objectives: The objective of this study is to determine the types of malignant patients admitted in the paediatric surgery department of BSMMU and also to know their age and sex distribution. Methods: This is a 5 years retrospective study from January 2005 to December 2009 in the paediatric surgery department of BSMMU, Dhaka, Bangladesh. All admitted malignant patients, aged up to 15 years diagnosed by means of histological or cytological examination included in this study. Results: Seventy (70) malignant patients were admitted during the study period, 65.7% patients were male and 34.3% patients were female with a male female ratio of 1.9:1. Fifty two (74.3%) patients were below 5 years and eighteen (25.7%) patients were between 5 to 15 years. The Wilms’ tumour was the most common malignant tumour which accounted for 42.8%. Hepatoblastoma was the second most common (24.2%). The other malignant tumours were neuroblastoma (15.7%), Non-Hodgkins lymphoma (5.7%), Rhabdomyosarcoma (4.2%), malignant fibrous histocytoma (1.4%), Fibroscarcoma (1.4%), Osteosarcoma (1.4%), malignant sacrococcygeal teratoma (1.4%), carcinoma of the rectum (1.4%0. Conclusion: Based on the result of this study, Wilms’ tumour is the commonest paediatric solid malignancy in our country. Carcinoma of the rectum may rarely occur in paediatric age group. Key words: Frequency; malignant solid tumor; children. DOI: http://dx.doi.org/10.3329/bsmmuj.v4i2.8638 BSMMU J 2011; 4(2):99-10

Evaluation of psychological distress in breast cancer patients during the COVID- 19 pandemic

Cancer patients are the vulnerable group of population and have more chances of contracting Corona virus disease 2019 (COVID-19). They are at great risk of passing through very stressful events during this COVID-19 pandemic that may lead to different psychological problems. Different psychological symptoms of breast cancer patients are evaluated in this study during the COVID- 19 pandemic. Consecutive fifty women selected with a non-metastatic breast cancer, scheduled to receive cancer treatment in the upcoming days/weeks not. Received treatment in the past, completed the Impact of Event Scale-Revised(IES-R), the Hospital Anxiety and Depression Scale (HADS-A and HADS-D), the Fear of Cancer Recurrence Inventory (FCRI). and the Insomnia Severity Index (ISI) and questionnaires. The study was conducted at Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from the 1st July 2020 to the 30th June 2021.. Patients were investigated about their worries regarding the impact of COVID-19 on their lives as carcinoma breast patients. Since the 1st July 2020 to the 30th June 2021, Consecutive 50 patients were prospectively evaluated. They were diagnosed with non-metastatic breast cancer. The mean age was 42.3 (range 30–70). Most of the patients (90%, n. 45) are married, 8% (n.4) patients are single and 2% (n. 1) patients are widowed. Among the patients 24 (48%) patients have high school or less education level, 19 (38%) have college experience and 7 (14%) have university degrees. Ten patients (20%) lived alone, 8 (16%) with one or two family members, and 32 (64%) with three or more family members. Concerning their working life, 36 (72%) were not working (namely housewives, retired, unemployed, or students) and 14 (28%) was occupied. In consideration of economic status 52% (n. 26) patients have annual family income in BDT 250001- 350000. On the other hand 22% (n. 11) within BDT 350001- 450000, 14% (n. 7) within BDT 150000- 250000, 6% (n. 3) within BDT 450001-550000 and 6% (n. 3) within BDT >550000 respectively. We found that 62% of patients had anxiety (HADS-A), 66% depression (HADS-D), and 68% fulfilled the diagnostic criteria for mild post-traumatic stress disorder (PTSD), 2% patients for moderate and 2% patients for severe PTSD. Results revealed that 50% (n.25) patients were suffering from subthreshold insomnia. On the other hand 46% (n.23) patients had no clinically significant Insomnia but 2% (n.1) patients had moderate and severe insomnia in each category. The Fear of Cancer Recurrence Inventory (FCRI) score was 14.7(SD±6.2) which was more than the cut-off value..Breast cancer patients pass through many stressful events that may develop significant psychological symptoms during this COVID-19 pandemic. The outcome of this study definitely contributes to understand the psychological distress of cancer patients and a to formulate a better plan for their management and psychological support. BSMMU J 2021; 14 (COVID -19 Supplement): 36-4

Plant cell culture technology in the cosmetics and food industries : current state and future trends

The production of drugs, cosmetics, and food which are derived from plant cell and tissue cultures has a long tradition. The emerging trend of manufacturing cosmetics and food products in a natural and sustainable manner has brought a new wave in plant cell culture technology over the past 10 years. More than 50 products based on extracts from plant cell cultures have made their way into the cosmetics industry during this time, whereby the majority is produced with plant cell suspension cultures. In addition, the first plant cell culture-based food supplement ingredients, such as Echigena Plus and Teoside 10, are now produced at production scale. In this mini review, we discuss the reasons for and the characteristics as well as the challenges of plant cell culture-based productions for the cosmetics and food industries. It focuses on the current state of the art in this field. In addition, two examples of the latest developments in plant cell culture-based food production are presented, that is, superfood which boosts health and food that can be produced in the lab or at home

Commonwealth Declaration for Empowerment of Junior Doctors

We, the representatives of Junior Doctors from National Medical Associations (NMAs) across the Commonwealth, assembled in Chennai, India, during the 27th Biennial Conference of the Commonwealth Medical Association – on 9th November 2024, acknowledge the vital contributions of junior doctors in delivering healthcare and the unique challenges they encounter in their early careers. This Commonwealth Declaration for Junior Doctors reaffirms our unified commitment to the well-being, growth, and resilience of junior doctors, recognizing their critical role as the backbone of healthcare systems. Grounded in the principles of equity, dignity, and empowerment, this Declaration aims to create supportive environments that safeguard the mental and emotional health of junior doctors, foster personal and professional development, and build their leadership capacity. With this Declaration, we call upon Governments, Health Institutions, and Professional Bodies across the Commonwealth to prioritize initiatives that address workplace violence, foster healthy work environments, and expand career and training opportunities within and beyond borders. We also advocate for strengthening mentorship, promoting research, supporting medical entrepreneurship, and building exchange programs to help junior doctors embrace family medicine, primary healthcare, and community-oriented practices. This collective commitment ensures a nurturing environment for junior doctors that will strengthen healthcare systems and enhance the well-being of communities across the Commonwealth