Synaptic dynamics in complex self-assembled nanoparticle networks.

We report a detailed study of neuromorphic switching behaviour in inherently complex percolating networks of self-assembled metal nanoparticles. We show that variation of the strength and duration of the electric field applied to this network of synapse-like atomic switches allows us to control the switching dynamics. Switching is observed for voltages above a well-defined threshold, with higher voltages leading to increased switching rates. We demonstrate two behavioral archetypes and show how the switching dynamics change as a function of duration and amplitude of the voltage stimulus. We show that the state of each synapse can influence the activity of the other synapses, leading to complex switching dynamics. We further demonstrate the influence of the morphology of the network on the measured device properties, and the constraints imposed by the overall network conductance. The correlated switching dynamics, device stability over long periods, and the simplicity of the device fabrication provide an attractive pathway to practical implementation of on-chip neuromorphic computing.

Variation of Antero-Posterior Diameter of Corpus Callosum in Different Age and Sex Groups of Bangladeshi People.

The corpus callosum (CC), the largest commissure of the brain, connects the two cerebral hemispheres and lies at the bottom of the longitudinal fissure. The antero-posterior diameter of the CC was larger in males than in females, but this difference was not significant. Again, the length of CC increased with age and there was also a positive significant correlation between the antero-posterior diameters of the CC with the antero-posterior diameter of the brain. This cross sectional descriptive study was performed into four categories: Group A (20-29 years), Group B (30-39 years), Group C (40-49 years) and Group D (50 years and above). The specimens were collected from morgue in the department of Forensic Medicine, Mymensingh Medical College, Bangladesh by purposive sampling technique Octy 2016 to Octy 2017. The antero-posterior diameter of CC was measured by using thread. The mean maximum antero-posterior diameter of corpus callosum was 8.25 cm in group D and minimum was 7.92 cm in Group A. When the diameter was compared between sexes in different age groups, it was significant in Group D and moderately significant in Group C. There was a positive correlation between antero-posterior diameter of corpus callosum and age of individual and it was statistically not significant. For statistical analysis, differences between age and sex groups were analyzed by using students unpaired 't' test. The present study will help to increase the information pool on the antero-posterior diameter of CC of Bangladeshi people and thus will minimize the dependency on foreign standards and also have diagnostic importance for the neurosurgeons and radiologists for clinical investigation and surgery.

Variation of Length of Parieto-Occipital Sulcus in Different Age and Sex Groups of Bangladeshi People.

Parieto-occipital sulcus is one of the major sulcus of the cerebral hemisphere which separates the occipital lobe from the parietal lobe. Morphology of this sulcus varies with age, sex, manual skill, handedness and in many diseases. For various clinical investigations and surgery, detailed morphological knowledge of this sulcus is very much essential for the surgeons and radiologists. This study is carried out to establish a normal standard in length of the parieto-occipital sulcus in different age and sex groups of Bangladeshi people. A cross-sectional, descriptive type of study was conducted in the department of Anatomy, Mymensingh Medical College, Bangladesh from July 2016 to July 2017. About 60 specimens were collected from medico-legal cases and divided into four age groups including, Group A (20-29 years), Group B (30-39 years), Group C (40-49 years) and Group D (50 years and above). The mean length of parieto-occipital sulcus was 3.92±0.559cm to 3.29±0.434 cm in male and 3.81±0.715cm to 3.03±0.551cm in female. The difference in mean length of the parieto-occipital sulcus for both left and right hemisphere between male and female was statistically non-significant in all age groups. For statistical analysis, differences between age and sex groups were analyzed by using students unpaired 't' test. In this study, the length of the parieto-occipital sulcus showed gradual decreasing values with advancing age.

Study of Number of Germinal Centers of Vermiform Appendix in Bangladeshi People of Different Age and Sex.

The vermiform appendix is a tubular, blind-ended secondary lymphoid organ located near the caecum, often referred to as the "tonsil of the abdomen" due to the abundance of lymphoid follicles in its histology. The presence of germinal centers, which are indicators of lymphatic tissue response to antigens and subsequent antibody production, helps assess the immune status of individuals. By counting these germinal centers, researchers can evaluate the immune status of the Bangladeshi population across different age and sex groups. This study was conducted at Mymensingh Medical College, approximately 120 km north of Dhaka, the capital of Bangladesh. Samples were randomly selected from the local population between 2016 and 2017, including 40 vermiform appendices from various age groups: Group A (up to 20 years), Group B (21-40 years), Group C (41-60 years) and Group D (over 60 years). After obtaining ethical approval, the germinal centers, identified by their lighter staining in the center of lymphoid follicles, were counted under a microscope (X4 objective, X10 eyepiece). The average number of germinal centers per age group was then calculated. The study found that the mean±SD number of germinal centers was 3.20±1.66, 2.40±0.66, 1.50±1.11 and 0.30±0.45 across the advancing age groups. The mean differences of number of germinal center between A&B, B&C were statistically non significant at p= or >0.05 level, difference between group C&D, A&C was statistically significant at p<0.05 level and differences between group B&D, A&D were statistically highly significant at p<0.001 level. Mean±SD number of germinal center of vermiform appendix in male was higher (3.60±1.02, 2.42±0.49, 1.50±1.26 and 0.33±0.47 in Group A, B, C and D respectively) than in female (2.80±1.17, 2.33±0.94, 1.30±0.87 and 0.25±0.43 in Group A, B, C and D respectively) but mean difference between sexes in the different groups was statistically non significant at p=or >0.05 level. Overall, the study observed a gradual decline in the number of germinal centers with increasing age.

A Morphometric Study of Glenoid Cavity of Scapula in Bangladeshi Population.

This cross-sectional descriptive purposive study was conducted among 150 (70 right and 80 left) fully ossified dry human scapulae of Bangladeshi people from January 2019 to December 2019 in the Department of Anatomy, Mymensingh Medical College, Mymensingh. Shape of the glenoid cavity was observed as pear, oval or inverted comma shape. Morphometric parameters such as length and breadth of glenoid cavity were measured by digital Vernier slide calipers. In this study, 19.13% cases were found inverted comma shaped, 35.65% cases were oval and 45.22% cases were pear shaped. The mean±SD length of glenoid cavity was 37.5±3.61 mm and 36.19±3.68 mm on right and left sided scapulae respectively and mean±SD breadth was 23.6±2.73 mm on right and 23.42±2.75 mm on left side respectively. Mean±SD glenoid cavity index was 62.89±4.39 on right and 64.61±4.74 on left sided scapulae. Morphometric analysis of glenoid fossa of scapula might help clinicians in shoulder and its associated diseases.

Variation of Acromiocoracoid and Acromioglenoid Distance in Bangladeshi People.

This cross-sectional descriptive purposive study was done on 150 (70 right and 80 left) fully ossified dry human scapulae of Bangladeshi people to find out the variation in length of acromiocoracoid and acromioglenoid distance. Sample collection was carried out in the Department of Anatomy, Mymensingh Medical College, Bangladesh from January to December 2019. Any kind of damaged or broken scapulae were excluded to maintain standard measurement. Length of these distances was measured with the help of digital Vernier slide calipers. The mean±SD acromiocoracoid distance were 35.8±4.64 mm and 36.32±5.55 mm on right and left sided scapulae respectively and the mean±SD acromioglenoid distance were 27.69±3.43 mm on right sided scapulae and 28.18±3.26 mm on left sided scapulae. These data are important to compare Bangladeshi scapulae to those from various other races that could contribute to demographic studies of shoulder disease probability and management in Bangladeshi population.

Variation of Mid shaft Antero-posterior and Transverse Diameter of Femur in Bangladeshi People.

Femoral morphometric variation is a dynamic system for different region, which is influenced by geographical, physiological and environmental factors, due to the adaptation, functional and remodeling responses of bones. This descriptive cross-sectional study was conducted on 150 (64 right and 86 left) fully ossified dry human femur of Bangladeshi people to find out the variation of mid shaft antero-posterior and transverse diameter of femur. Sample was collected in the Department of Anatomy, Mymensingh Medical College (MMC), Bangladesh from January 2019 to December 2019. All samples were assessed to eliminate fractured, pathologically damaged and remodeled bones. The diameters were measured with the help of digital Vernier slide calipers. The mean±SD mid shaft antero-posterior diameter of right and left femur were 25.03±2.86 mm and 25.54±2.65mm respectively. The mean±SD transverse diameter of right and left femur was 24.24±2.43mm and 24.54±2.38mm respectively. The knowledge of variations in the parameters of dry femora will help the orthopedicians for the treatment and management of femoral shaft fracture. These data also provide information about mid shaft diameter of femur of Bangladeshi people and to compare these data to those from various other races. Thus it could contribute for the design of well-fitting prosthesis which suits the Bangladeshi population. This value may be considered while making a best-fit femoral prosthesis.

Tuning the Kondo effect in thin Au films by depositing a thin layer of Au on molecular spin-dopants.

We report on the tuning of the Kondo effect in thin Au films containing a monolayer of cobalt(II) terpyridine complexes by altering the ligand structure around the Co(2+) ions by depositing a thin Au capping layer on top of the monolayer on Au by magnetron sputtering (more energetic) and e-beam evaporation (softer). We show that the Kondo effect is slightly enhanced with respect to that of the uncapped film when the cap is deposited by evaporation, and significantly enhanced when magnetron sputtering is used. The Kondo temperature (TK) increases from 3 to 4.2/6.2 K for the evaporated/sputtered caps. X-ray absorption spectroscopy and surface-enhanced Raman spectroscopy investigation showed that the organic ligands remain intact upon Au e-beam evaporation; however, sputtering inflicts significant change in the Co(2+) electronic environment. The location of the monolayer-on the surface or embedded in the film-has a small effect. However, the damage of Co-N bonds induced by sputtering has a drastic effect on the increase of the impurity-electron interaction. This opens up the way for tuning of the magnetic impurity states, e.g. spin quantum number, binding energy with respect to the host Fermi energy, and overlap via the ligand structure around the ions.

Development of Consensus Recommendations on the Management of Vitiligo and the Role of Decapeptide in Vitiligo by the Delphi Method.

Background: Treatment of vitiligo is still a challenge in dermatology. Literature is sparse on the definitive clinical role of basic fibroblast growth factor (bFGF) in vitiligo patients. Aims: We decided to generate a consensus in an attempt to answer some critical questions related to the management of vitiligo and the role of bFGF. Materials and Methods: A Delphi method among 21 experts across India was conducted. A consensus (agreement was 75% or greater) was taken on 27 statements on the prevalence, epidemiology, and treatment of vitiligo and the role of bFGF in the management of vitiligo. The consensus process was completed after two rounds. Results: Topical corticosteroid therapy is the first-line therapy for vitiligo; however, its adverse effects are widely known, especially in sensitive areas. Topical calcineurin inhibitors are preferred in stable vitiligo of the face, neck, genitals, or intertriginous regions as an alternative to topical corticosteroids. Topical bFGF is a relatively newer therapy with a promising role in stable vitiligo. bFGF is safe and effective in inducing repigmentation of vitiligo lesions. Combination therapy of bFGF with other topical therapies, phototherapy, and surgical procedures can be beneficial in patients of vitiligo. Conclusion: This consensus would complement the currently available literature on bFGF and help the practitioner to recognize the unmet need in the treatment of vitiligo.

Multi-Scale hierarchical generation of PET parametric maps: application and testing on a [11C]DPN study.

We propose a general approach to generate parametric maps. It consists in a multi-stage hierarchical scheme where, starting from the kinetic analysis of the whole brain, we then cascade the kinetic information to anatomical systems that are akin in terms of receptor densities, and then down to the voxel level. A-priori classes of voxels are generated either by anatomical atlas segmentation or by functional segmentation using unsupervised clustering. Kinetic properties are transmitted to the voxels in each class using maximum a posteriori (MAP) estimation method. We validate the novel method on a [11C]diprenorphine (DPN) test-retest data-set that represents a challenge to estimation given [11C]DPN's slow equilibration in tissue. The estimated parametric maps of volume of distribution (VT) reflect the opioid receptor distributions known from previous [11C]DPN studies. When priors are derived from the anatomical atlas, there is an excellent agreement and strong correlation among voxel MAP and ROI results and excellent test-retest reliability for all subjects but one. Voxel level results did not change when priors were defined through unsupervised clustering. This new method is fast (i.e. 15 min per subject) and applied to [11C]DPN data achieves accurate quantification of VT as well as high quality VT images. Moreover, the way the priors are defined (i.e. using an anatomical atlas or unsupervised clustering) does not affect the estimates.

Striatal dopamine synthesis capacity in twins discordant for schizophrenia.

BACKGROUND: Elevated striatal dopamine synthesis capacity is thought to be fundamental to the pathophysiology of schizophrenia and has also been reported in people at risk of psychosis. It is therefore unclear if striatal hyperdopaminergia is a vulnerability marker for schizophrenia, or a state feature related to the psychosis itself. Relatives of patients with schizophrenia are themselves at increased risk of developing the condition. In this study we examined striatal dopamine synthesis capacity in both members of twin pairs discordant for schizophrenia. METHOD: In vivo striatal dopamine synthesis capacity was examined using fluorine-18-l-dihydroxyphenylalanine (18F-DOPA) positron emission tomography (PET) scans in seven twin pairs discordant for schizophrenia and in a control sample of 10 healthy control twin pairs. RESULTS: Striatal 18F-DOPA uptake was not elevated in the unaffected co-twins of patients with schizophrenia (p=0.65) or indeed in the twins with schizophrenia (p=0.89) compared to the control group. Levels of psychotic symptoms were low in the patients with schizophrenia who were in general stable [mean (s.d.) Positive and Negative Syndrome Scale (PANSS) total=56.8 (25.5)] whereas the unaffected co-twins were largely asymptomatic. CONCLUSIONS: Striatal dopamine synthesis capacity is not elevated in symptom-free individuals at genetic risk of schizophrenia, or in well-treated stable patients with chronic schizophrenia. These findings suggest that striatal hyperdopaminergia is not a vulnerability marker for schizophrenia.

Measurement of Placental Index in Different Gestational Age Groups in Bangladeshi Women.

Placenta is the mirror of maternal and fetal status; it reflects the changes due to complications in pregnancy of mother. The growth and survival of the fetus in utero is directly related to formation, development and maturation of the placenta. Placental index was correlated to poor pregnancy outcomes. Placental index can help to identify fetal growth restriction which is result of placental insufficiency and is characterized by insufficient trasnsplacental transport of nutrients and oxygen. This cross sectional descriptive study would provide information about the ratio of placental index in different gestational age group in Bangladeshi women. To achieve this aim the study was performed on 60 human placenta and corresponding fetuses and gestational age (in weeks) categorized as Group A (28-32), Group B (33-37), Group C (38-40). These sample and information were collected from normal pregnancy in Gynecology and Obstetrics Department of Mymensingh Medical College Hospital from July 2009 to June 2010. After preservation in 10% formal saline, study was done in Department of Anatomy in Mymensingh Medical College. In this study, the mean±SD placental index was in Group A (0.187±0.113), Group B (0.153±0.025) and Group C (0.166±0.025) and also observed that mean placental index decreased with age up to certain level then increase in Group C. The mean placental index was maximum in Group A (0.187±0.113) and was minimum in Group B (0.153±0.025). The mean difference of placental index between Groups A&B, A&C and B&C was statistically not significant. Observed findings of this study were compared with those of Western and Bangladeshi researches.

A Postmortem Study of Length & Depth of the Central Sulcus in Different Age & Sex Groups of Bangladeshi People.

The central sulcus (CS) is a prominent landmark of the brain, separating the parietal lobe from the frontal lobe and the primary motor cortex from the primary somatosensory cortex. Variations in the morphology of the central sulcus are seen with respect to the length and depth of the central sulcus. This study was done to establish a normal standard of length and depth of central sulcus in different age and sex groups of Bangladeshi people. Interhemispheric age and gender differences of the central sulcus were done by cross sectional descriptive study which was performed into four categories- Group A (20 to 29 years), Group B (30 to 39 years), Group C (40 to 49 years) and Group D (50 years & above). The specimens were collected from morgue in the department of Forensic Medicine, Mymensingh Medical College, Bangladesh by purposive sampling technique. The length of central sulcus was measured by using thread and the depth was measured by using wooden stick at middle of the upper, middle and lower third of the central sulcus in superolateral surface. The mean length of central sulcus was 10.51±0.529cm to 9.78±0.996cm in male and 10.27±0.786cm to 8.83±0.379cm in female. Depth of the central sulcus was 1.333±0.100cm to 1.029±0.125cm in male and 1.173±0.144cm to 1.01±0.200cm in female. The difference in mean length & depth of the central sulcus for both left and right hemisphere between male and female was statistically non significant in all age groups. In present study the length and depth of the central sulcus showed gradual decreasing values with advancing age. Knowledge of morphometry of central sulcus is not only important during neurosurgery of brain but also holds tremendous significance in diagnosis and management of diseases of the cerebral cortex. The present study will help to increase the information pool on the length and depth of the central sulcus of Bangladeshi people which will minimize the dependency on foreign standards.

Length of Umbilical Cord in Different Gestational Age Groups of Healthy Pregnant Mother of Bangladesh.

This cross sectional descriptive study was performed on 80 human placenta and umbilical cord to find out the variation in length of umbilical cord of healthy Bangladeshi mother in relation to different gestational age. This study was conducted in the Department of Anatomy, Mymensingh Medical College, Mymensingh, from January to December 2018. The specimens were collected from the Department of Gynaecology and Obstetrics, Mymensingh Medical College Hospital, Mymensingh, Bangladesh by purposive sampling technique. According to gestational age the collected samples were divided into three groups. They were Group A (28 to 36 weeks), Group B (37 to 40 weeks) and Group C (above 40 weeks) and examined morphologically by fine dissection method. The length of umbilical cord was measured with the help of flexible tape in cm. For statistical analysis, differences of length between age groups were analyzed by using unpaired student 't' test. The mean±SD length of umbilical cord was 56.15±7.61cm in Group A, 62.54±8.78cm in Group B and 68.54±10.53cm in Group C. It was also observed that the mean length of the umbilical cord was increased with increase of gestational age. The mean difference of length of umbilical cord between Groups A and C was statistically highly significant (p<0.001), difference between Groups A and B was statistically moderately significant (p<0.01) but the difference between Groups B and C was statistically significant (p<0.05). This study was done to provide information about the length of umbilical cord in different gestational ages of healthy pregnancies.

Electron-phonon coupling and spin fluctuations in 3d and 4d transition metals: implications for superconductivity and its pressure dependence.

We have calculated the electron-phonon coupling for the complete 4d series and the nonmagnetic 3d transition metals using the linear response method and the linear muffin-tin orbitals' basis. A comparison of the linear response results and those obtained via the rigid muffin-tin approximation is provided. Based on the calculated values of the electron-phonon coupling constants, band density of states and the measured values of the electronic specific heat constants, we estimate the spin-fluctuation effects, i.e. the electron-spin-fluctuation (electron-paramagnon) coupling constants in these systems. For the sake of comparison, several other metals, Cu, Zn, Ag, Cd, Al and Pb, are also studied. Alternative estimates of the electron-paramagnon coupling constants are obtained from the values of the Stoner parameters and the band densities of states at the Fermi level. Implications of these results on the superconductivity and its pressure dependence as well as the alloying effects of superconductivity in these systems are discussed. It is pointed out that spin fluctuations play an important role in the validity of the Matthias rule that in metallic systems the optimum conditions for (electron-phonon) superconductivity occur for 5 and 7 valence electrons/atom.

Avalanches and criticality in self-organized nanoscale networks.

Current efforts to achieve neuromorphic computation are focused on highly organized architectures, such as integrated circuits and regular arrays of memristors, which lack the complex interconnectivity of the brain and so are unable to exhibit brain-like dynamics. New architectures are required, both to emulate the complexity of the brain and to achieve critical dynamics and consequent maximal computational performance. We show here that electrical signals from self-organized networks of nanoparticles exhibit brain-like spatiotemporal correlations and criticality when fabricated at a percolating phase transition. Specifically, the sizes and durations of avalanches of switching events are power law distributed, and the power law exponents satisfy rigorous criteria for criticality. These signals are therefore qualitatively and quantitatively similar to those measured in the cortex. Our self-organized networks provide a low-cost platform for computational approaches that rely on spatiotemporal correlations, such as reservoir computing, and are an important step toward creating neuromorphic device architectures.

Variations in the Position of Vermiform Appendix in Bangladeshi People.

This cross sectional descriptive study was performed on 70 postmortem vermiform appendices (male 34 and female 36) to find out the various positions of vermiform appendix of Bangladeshi people. The specimens were collected from autopsy laboratory of the Department of Forensic Medicine, Mymensingh Medical College, Mymensingh, Bangladesh by purposive sampling technique from October 2016 to March 2017. The collected samples were divided into four age groups. They were Group A (upto 20 years), Group B (21 to 40 years), Group C (41 to 60 years) and Group D (above 60 years). Dissection was performed according to standard autopsy technique. During postmortem examination abdominal cavity was routinely exposed by classical midline incision from xiphoid process to the symphysis pubis and a semicircular incision around the umbilicus and the flaps were reflected to give a good view of the abdominal cavity along with its contents and then the taeniae coli of the caecum were identified. The three taeniae coli of the caecum converge at the base of the appendix and become its longitudinal muscle coat. The anterior caecal taeniae coli acts as the best guide for identification of the vermiform appendix. The relation of the base of the appendix to the caecum is constant but the position of the vermiform appendix, which is variable, was studied in relation to caecum and the terminal part of the ileum. Accordingly the position of the vermiform appendix was noted either retrocaecal, pelvic, preileal or postileal, subcaecal. All data were recorded in the predesigned data sheet, analyzed by SPSS program (version 21, 2012) and compared with the findings of other national and international studies and standard text books. Among 70 specimens, 44(62.9%) vermiform appendices were retrocaecal in position. The next common position was pelvic which was in 22(31.4%) specimen followed by postileal in 3(4.3%) specimen and subcaecal was observed only in 1(1.4%) specimen. In this study in all age groups incidence of retrocaecal vermiform appendix was highest and it was about 67.6%, 50%, 69.2% and 72.7% in Group A, B, C, D respectively. Pelvic position was 7.1%, 46.9%, 23.1% and 27.3% in Group A, B, C, D respectively. Subcaecal vermiform appendix was absent in Group A, B and Group D. On the other hand postileal vermiform appendix was absent in Group C and Group D. The findings of this study may help the physician and the surgeons for proper diagnosis, management and treatment of disease of vermiform appendix.

Positive and negative aspects of soda/anthraquinone pulping of hardwoods.

The positive aspects of the non-sulfur soda/anthraquinone (SAQ) process are mostly tied to improved energy efficiency while lower pulp brightness after bleaching is its most significant drawback. A credible method that quantifies bleachability as well as an approach that solves the problem for SAQ pulps from hardwoods will be described. A straight line correlation (R2=0.904) was obtained between O2 kappa number and final light absorption coefficient (LAC) value after standardized OD0EpD1 bleaching of nine hardwood kraft pulps from three laboratories and one pulp mill. The bleachability of pulps from four different soda processes catalyzed by anthraquinone (AQ) and 2-methylanthraquinone (MAQ) was compared to that of conventional kraft pulps by comparing O2 kappa number decrease and final LAC values. It was observed that a mild hot water pre-hydrolysis improved the bleachability of SAQ pulps to a level equal to that of kraft.