Charge transport mechanisms of PbSnSe2 and observation of transition from direct to Fowler-Nordheim tunneling.

In this study, we report the observation of various conduction mechanisms in mechanically exfoliated PbSnSe2 based on temperature-dependent current and voltage characteristics. A transition from direct tunneling to Fowler-Nordheim tunneling in PbSnSe2 was observed at 2.63 V. At lower temperatures, the 3D Mott variable range hopping model fits the data, yielding a density of states of ∼8.80 × 1020 eV-1 cm-3 at 2 V. The values of Whop and Rhop were 64 meV and 22.7 nm, respectively, at 250 K. The Poole-Frenkel conduction was observed in the Au/PbSnSe2/Au device and the dielectric constant of PbSnSe2 was calculated to be 1.4. At intermediate voltages, a space charge limited current with an exponential distribution of traps was observed and a trap density of ∼9.53 × 1013 cm-3 and a trap characteristic temperature of 430 K were calculated for the Au/PbSnSe2/Au device.

Spontaneous posterior rectus sheath hernia: A case report and literature review.

INTRODUCTION: Hernias of the posterior rectus sheath are very rare abdominal wall hernias with only around 15 reported cases to date. CLINICAL PRESENTATION: This case report examines a 27-year-old female who is presented with epigastric abdominal pain and vomiting. An Abdomen CT scan was done and showed signs of SBO and herniation of the small bowel at the posterior rectus sheath. The patient underwent exploratory laparotomy that showed right-sided posterior rectus sheath obstructed hernia, which was repaired with primary closure. Postoperatively, the patient was doing well and was discharged on postoperative day 3 in good general condition. CONCLUSION: The patient had no complaints during her follow-up at one month. Due to its rarity and potential complications, it is also important to report this case to enhance the evidence base for posterior rectus sheath hernia and to familiarise this uncommon condition to radiologists, clinicians, and surgeons.

Gallbladder lymphangioma simulating liver hydatid cyst: A case report.

INTRODUCTION AND IMPORTANCE: Gallbladder lymphangiomas are very-rare, yet benign tumors that start developing in early life. Those tumors often go unnoticed until adulthood as they grow into a larger size or a complication happens. Despite its rarity, suspicion for the diagnosis should be maintained by the physicians. CASE PRESENTATION: A 14-year-old female patient presented to the hospital complaining of right upper quadrant abdominal pain of one month duration. Physical examination showed mild upper quadrant tenderness. Serology testing for the patient only showed eosinophilia. Computed tomography showed a large non-enhancing cystic lesion attached to the gallbladder. Presumptive diagnosis of hydatid cyst was made, and the patient was treated accordingly. Histological analysis of mass showed dilated lymphatic vessels, hence the shift in diagnosis towards a lymphangioma was made. CLINICAL DISCUSSION: Gallbladder lymphangioma are usually asymptomatic, but they can present with pain, nausea and vomiting. Multiple complications had been reported including compression of the nearby structures, intra-abdominal infection, rupture, torsion or hemorrhagic transformation. Surgical removal of the mass is the treatment of choice. CONCLUSIONS: Right upper quadrant pain can be the presenting symptom of liver pathology. Histological assessment is needed to confirm the diagnosis which will show dilated lymphatic vessels.

Solution combustion synthesis: the relevant metrics for producing advanced and nanostructured photocatalysts.

The current developments and progress in energy and environment-related areas pay special attention to the fabrication of advanced nanomaterials via green and sustainable paths to accomplish chemical circularity. The design and preparation methods of photocatalysts play a prime role in determining the structural, surface characteristics and optoelectronic properties of the final products. The solution combustion synthesis (SCS) technique is a relatively novel, cost-effective, and efficient method for the bulk production of nanostructured materials. SCS-fabricated metal oxides are of great technological importance in photocatalytic, environmental and energy applications. To date, the SCS route has been employed to produce a large variety of solid materials such as metals, sulfides, carbides, nitrides and single or complex metal oxides. This review intends to provide a holistic perspective of the different steps involved in the chemistry of SCS of advanced photocatalysts, and pursues several SCS metrics that influence their photocatalytic performances to establish a feasible approach to design advanced photocatalysts. The study highlights the fundamentals of SCS and the importance of various combustion parameters in the characteristics of the fabricated photocatalysts. Consequently, this work deals with the design of a concise framework to link the fine adjustment of SCS parameters for the development of efficient metal oxide photocatalysts for energy and environmental applications.

Sustainable chemical processing of flowing wastewater through microwave energy.

Iron oxide nanostructured catalysts have emerged as potential candidates for efficient energy conversion and electrochemical energy storage devices. However, synthesis and design of nanomaterial plays a key role in its performance and efficiency. Herein, we describe a one-pot solution combustion synthesis (SCS) of α-Fe2O3 with glycine as a fuel, and a subsequent reduction step to produce iron-containing catalysts (i.e., Fe3O4, Fe-Fe3O4, and Fe0). The synthesized iron-based nanoparticles were investigated for methyl orange (MO) degradation through Microwave (MW) energy under continuous flow conditions. Fe-Fe3O4 showed higher MO degradation efficiency than α-Fe2O3, Fe3O4 and Fe0 at low absorbed MW power (i.e. 5-80 W). The enhanced degradation efficiency is associated to the combination of higher availability of electron density and higher heating effect under MW energy. Investigation of dielectric properties showed relative dielectric loss of Fe3O4, Fe-Fe3O4, and Fe0 as 3847, 2010, and 1952, respectively. The calculated average local temperature by the comparative analysis of MW treatment with conventional thermal (CT) treatment showed a marked thermal effect of MW-initiated MO degradation. This work highlights the potential of microwave-driven water depollution under continuous-flow processing conditions and demonstrates the positive impact that earth-abundant Fe catalyst synthesized by green SCS method can have over the treatment of wastewater.

Study of electric conduction mechanisms in bismuth silicate nanofibers.

This work represents the nature of conduction mechanism in bismuth silicate (BiSiO) nanofibers as a function of temperature and frequency. Scanning electron micrographs and X-rays diffraction patterns exhibited the formation of cubic phases of Bi4(SiO4)3 and Bi12SiO20 nanofibers respectively with an average diameter of ~200 nm. Temperature dependent (300 K-400 K) electrical characterization of fibers was carried out in frequency range of ~20 Hz-2 MHz. The complex impedance analysis showed contribution from bulk and intergranular parts of nanofibers in conduction. Moreover, analysis of the Cole-Cole plot confirmed the space charge dependent behavior of BiSiO nanofibers. Two types of relaxation phenomena were observed through Modulus analysis. In ac conductivity curve, step like feature of plateau and dispersive regions were described by Maxwell-Wagner effect while the dc part obeyed the Arrhenius law. However, frequency dependent ac conductivity revealed the presence of conduction mechanism in diverse regions that was ascribed to large polaron tunneling model. Detailed analysis of complex Impedance and ac conductivity measurement showed negative temperature coefficient of resistance for the BiSiO nanofibers. Current-voltage (IV) characteristics represented ohmic conduction; followed by space charge limited current conduction at intermediate voltages. Results from both ac and dc measurements were in good agreement with each other.

Development of High-Performance Bismuth Sulfide Nanobelts Humidity Sensor and Effect of Humid Environment on its Transport Properties.

Orthorhombic phase bismuth sulfide (Bi2S3) nanobelts were prepared via  liquid-solid phase reaction method. Bi2S3 nanobelts were observed to be preferentially oriented along the (101) plane. Direct band gap (2.95 eV) and characteristic wavelength (λmax = 342 nm) were extracted through UV-visible spectroscopy. Specific surface area (9.8 m2/g) and pore size (2.5-120 nm) were evaluated through Brunauer-Emmett-Teller (BET) analysis. Relative humidity (RH) sensing properties were studied in the range of 11-97% RH at ambient conditions. The response of the sensor increases linearly with increase in RH. Fast response time (8-10 s) and recovery time (15 s) were observed. Reproducible and large response was also observed between 11 and 97% RH. Small hysteresis (<5%) and long-term stability during 30 days were confirmed. As a function of frequency, capacitance, alternating current conductivity, and electrical complex modulus in the frequency range of 20-2 MHz were studied at 11-97% RH. The sensing mechanism was also studied.

Mapping autosomal recessive intellectual disability: combined microarray and exome sequencing identifies 26 novel candidate genes in 192 consanguineous families.

Approximately 1% of the global population is affected by intellectual disability (ID), and the majority receive no molecular diagnosis. Previous studies have indicated high levels of genetic heterogeneity, with estimates of more than 2500 autosomal ID genes, the majority of which are autosomal recessive (AR). Here, we combined microarray genotyping, homozygosity-by-descent (HBD) mapping, copy number variation (CNV) analysis, and whole exome sequencing (WES) to identify disease genes/mutations in 192 multiplex Pakistani and Iranian consanguineous families with non-syndromic ID. We identified definite or candidate mutations (or CNVs) in 51% of families in 72 different genes, including 26 not previously reported for ARID. The new ARID genes include nine with loss-of-function mutations (ABI2, MAPK8, MPDZ, PIDD1, SLAIN1, TBC1D23, TRAPPC6B, UBA7 and USP44), and missense mutations include the first reports of variants in BDNF or TET1 associated with ID. The genes identified also showed overlap with de novo gene sets for other neuropsychiatric disorders. Transcriptional studies showed prominent expression in the prenatal brain. The high yield of AR mutations for ID indicated that this approach has excellent clinical potential and should inform clinical diagnostics, including clinical whole exome and genome sequencing, for populations in which consanguinity is common. As with other AR disorders, the relevance will also apply to outbred populations.

Investigation of change in surface area and grain size of cadmium titanate nanofibers upon annealing and their effect on oxygen sensing.

We have investigated the phase changes in CdTiO3 nanofibers as the annealing temperature of nanofibers was increased from 600 to 1200 °C. The nanofibers annealed at 600 °C were ilmenite with a very small amount of CdO. Upon annealing at 950 °C, CdO was completely removed. Annealing at 1000 °C yielded pure perovskite nanofibers, and at temperatures above 1100 °C rutile TiO2 nanofibers were obtained. Brunauer-Emmett-Teller (BET) analysis showed that with increase in annealing temperature the surface area of nanofibers was decreased. The nanofibers annealed at 600 °C have the higher surface area of ∼9.41 m(2)/g. Then oxygen sensors using CdTiO3 nanofibers annealed at 600 °C (ilmenite) and 1000 °C (perovskite) were fabricated. The sensitivity of the ilmenite nanofibers sensor was 2 times than that of the perovskite nanofibers sensor. The response and recovery times were 120 and 23 s, respectively, for the ilmenite nanofibers sensor, whereas response and recovery times were 156 and 50 s, respectively, for the perovskite nanofibers sensor. Better oxygen characteristics of ilmenite nanofibers are attributed to their large surface area and porosity. Therefore, we believe that ilmenite CdTiO3 nanofibers are potential candidates to develop practical oxygen sensors.

Mapping of three novel loci for non-syndromic autosomal recessive mental retardation (NS-ARMR) in consanguineous families from Pakistan.

To date, of 13 loci with linkage to non-syndromic autosomal recessive mental retardation (NS-ARMR), only six genes have been established with associated mutations. Here we present our study on NS-ARMR among the Pakistani population, where people are traditionally bound to marry within the family or the wider clan. In an exceptional, far-reaching genetic survey we have collected more than 50 consanguineous families exhibiting clinical symptoms/phenotypes of NS-ARMR. In the first step, nine families (MR2-9 and MR11) with multiple affected individuals were selected for molecular genetic studies. Two families (MR3, MR4) showed linkage to already know NS-ARMR loci. Fifteen affected and 10 unaffected individuals from six (MR2, MR6, MR7, MR8, MR9 and MR11) families were genotyped by using Affymetrix 5.0 or 6.0 single-nucleotide polymorphism (SNP) microarrays. SNP microarray data was visually inspected by dChip and genome-wide homozygosity analysis was performed by HomozygosityMapper. Additional mapping was performed (to exclude false-positive regions of homozygosity called by HomozygosityMapper and dChip) on all available affected and unaffected members in seven NS-ARMR families, using microsatellite markers. In this manner we were able to map three novel loci in seven different families originating from different areas of Pakistan. Two families (MR2, MR5) showed linkage on chromosome 2p25.3-p25.2. Three families (MR7, MR8, and MR9) that have been collected from the same village and belong to the same clan were mapped on chromosome 9q34.3. MR11 maps to a locus on 9p23-p13.3. Analysis of MR6 showed two positive loci, on chromosome 1q23.2-q23.3 and 8q24.21-q24.23. Genotyping in additional family members has so far narrowed, but not excluded the 1q locus. In summary, through this study we have identified three new loci for NS-ARMR, namely MRT14, 15 and 16.

Aposthia: a birth defect or normal quantitative recessive human genetic trait?

Aposthia (natural circumcision) is the condition of being born without a prepuce. Usually sporadic cases are reported in the medical literature. In this paper for the first time we present the genetic profile of 3 families with aposthia trait and discuss the possible genetics.

Aposthia: a birth defect or normal quantitative recessive human genetic trait?

Aposthia [natural circumcision] is the condition of being born without a prepuce. Usually sporadic cases are reported in the medical literature. In this paper for the first time we present the genetic profile of 3 families with aposthia trait and discuss the possible genetics

Localization of a novel locus for hereditary nail dysplasia to chromosome 17q25.1-17q25.3.

We report on a six-generation Pakistani consanguineous family with autosomal recessive transmission of a form of hereditary nail dysplasia. Affected individuals presented with onycholysis of fingernails and anonychia of toenails. Associated abnormalities of ectodermal appendages were not observed in any of the affected individuals. Linkage has been established to chromosome 17q. A maximum multipoint analysis logarithm of the odds ratio score of 4.85 was obtained at marker D17S1301. Due to the consanguineous nature of this kindred, the gene for nail dysplasia is probably contained within a 5.0-cM (3 MB on the sequence-based physical map) region of homozygosity flanked by markers D17S1807 and D17S937.

Linkage mapping of a nonspecific form of X-linked mental retardation (MRX53) in a large Pakistani family.

Nonspecific X-linked mental retardation is a nonprogressive, genetically heterogeneous condition that affects cognitive function in the absence of other distinctive clinical manifestations. We report here linkage data on a large Pakistani family affected by a form of X-linked nonspecific mental retardation. X chromosome genotyping of family members and linkage analysis allowed the identification of a new disease locus, MRX53. The defined critical region spans approximately 15 cM between DXS1210 and DXS1047 in Xq22.2-26. A LOD score value of 3.34 at no recombination was obtained with markers DXS1072 and DXS8081.