Microporous Zr-metal-organic frameworks based-nanocomposites for thermoelectric applications.

In the area of energy storage and conversion, Metal-Organic Frameworks (MOFs) are receiving more and more attention. They combine organic nature with long-range order and low thermal conductivity, giving them qualities to be potentially attractive for thermoelectric applications. To make the framework electrically conductive so far, thermoelectricity in this class of materials requires infiltration by outside conductive guest molecules. In this study, an in-situ polymerization of conductive polyaniline inside the porous structure of MOF-801 was conducted to synthesize PANi@MOF-801 nanocomposites for thermoelectrical applications. The growth of polyaniline chains of different loadings inside the host MOF matrix generally enhanced bulk electrical conductivity by about 6 orders of magnitude, leading to Seebeck coefficient value of -141 µVK-1 and improved thermal stability. The unusual increase in electrical conductivity was attributed to the formation of highly oriented conductive PANi chains inside the MOF pores, besides host-guest physical interaction, while the Seebeck coefficient enhancement was because of the energy filtering effect of the developed structure. Modulating the composition of PANi@MOF-801 composites by varying the aniline: MOF-801 ratio in the synthesis bath from 2:1 and 1:1 to 1:2 leads to a change in the semiconductor properties from p-type semiconductor to n-type. Among the examined composites with n-type semiconducting properties exhibited the highest ZT value, 0.015, and lowest thermal conductivity, 0.24 Wm-1 K-1. The synthesized composites have better performance than those recently reported for a similar category of thermoelectric materials related to MOF-based composites.

Free-standing interconnected carbon nanofiber electrodes: new structural designs for supercapacitor application.

This work aims to develop and characterize a new design of free-standing interconnected carbon nanofiber electrodes for supercapacitor application. The fibers are obtained via carbonization of three components of electrospun nanofiber mats based on a polyacrylonitrile polymer (as a carbon backbone precursor), polyvinylalcohol (as a sacrificial copolymer), and 0-1.0 wt% multi-walled carbon nanotubes. Carbonizing these ternary composites results in fibers with about twice as large in surface area and one order of magnitude higher in electrical conductivity than those obtained by the carbonization of neat polyacrylonitrile and/or binary polyacrylonitrile-0-1.0 wt% carbon nanotube mats. The carbonized polyacrylonitrile-polyvinylalcohol-0.3 wt% carbon nanotube mat reveals the highest surface area and electrical conductivity and best capacitive performance. It exhibits energy and power densities of 27.8 Wh kg-1 and 110.59 kW kg-1, respectively, and cyclic stability of 95% after 2000 charge-discharge cycles at a charging current of 1.0 Ag-1. The nanotubes' alignment along the fiber's axis, the formation of fiber-fiber interconnected morphology with more mesopore pollution, and changes in the graphitization degree and defect features of fiber crystallites are the reasons for the observed increase in the electrical conductivity, surface area, and capacitive performance of the carbon fibers. Therefore, the new design represents a potential free-standing carbon nanofiber electrode for future electrochemical double layer capacitor (EDLC) device fabrication.

3D hierarchical graphene/CNT with interfacial polymerized polyaniline nano-fibers.

In this work Polyaniline (PANI) fiber has been synthetized by the interfacial polymerization method. The thermal behavior of graphene - multiwall carbon nanotubes (MWCNs) composite material (C-Mix) blended with PANI fiber was investigated. Graphene was prepared by thermal reduction of the fabricated graphene oxide (GO) using modified Hummers' method. SEM measurement reveals that MWCNTs were well organized within 2D large surface area graphene nano-sheets to form 3D carbon-base hierarchical structure, and PANI was mixed as a binder polymer matrix. Structural measurements confirm the formation of wide area graphene sheets with crumples, wrinkles, and folds around the edges. Transmission electron microscopy (TEM) images agreed with the well distribution of CNTs within graphene nano-sheets. Also, the surface morphology of the synthesized composites has a spherical regular agglomeration of PANI granular structure on wide area graphene nano sheets with CNT embedded. The change in the existed phonon modes of the fabricated nano-composite was analyzed using Raman spectroscopy. Moreover, Seebeck coefficient changes from +132.4 µV/K to -10.3 µV/K after adding carbon-based materials which reflects the reverse of predominate carriers by doping PANI with carbon-based material. It has been noticed that there is an enhancement of thermal conductivity of the fabricated composite with respect to neat polymer. Hence, we propose that 3D carbon structure with PANI construct a stable N-Type thermoelectric material.

Survey of skin disorders in newborns: clinical observation in an Egyptian medical centre nursery.

The frequency of neonatal skin disorders has not been well studied in Egypt. Our aim was to address patterns of dermatological changes in a sample of Egyptian newborns. In a descriptive prospective cohort study 600 newborns in Sohag University hospital nursery were dermatologically examined within the first 5 days of birth. Skin disorders were detected in 240 neonates (40.0%). Birthmarks were found in 100 neonates (16.7%), mainly melanocytic type (mongolian spots in 11.7% and congenital melanocytic naevi in 2.7%). Fungal skin infections, including oral moniliasis, fungal infection in the napkin area or candidal intertrigo, were detected in 13.3% and bacterial infections in 1.3% of neonates. Comparisons with other studies worldwide indicated a higher rate of fungal infections and lower rate of birthmarks in our study. Routine neonatal dermatological evaluation is recommended, especially in view of the high rate of fungal skin infections.

Survey of skin disorders in newborns: clinical observation in an Egyptian medical centre nursery

The frequency of neonatal skin disorders has not been well studied in Egypt. Our aim was to address patterns of dermatologicaf changes in a sample of Egyptian newborns. In a descriptive prospective cohort study 600 newborns in Sohag University hospital nursery were dermatologically examined within the first 5 days of birth. Skin disorders were detected in 240 neonates [40.0%]. Birthmarks were found in 100 neonates [16.7%], mainly melanocytic type [mongolian spots in 11.7% and congenital melanocytic naevi in 2.7%]. Fungal skin infections, including oral moniliasis, fungal infection in the napkin area or candidal intertrigo, were detected in 13.3% and bacterial infections in 1.3% of neonates. Comparisons with other studies worldwide indicated a higher rate of fungal infections and lower rate of birthmarks in our study. Routine neonatal dermatological evaluation is recommended, especially in view of the high rate of fungal skin infections

Case with autistic syndrome and chromosome 22q13.3 deletion detected by FISH.

Autism is a rare neurodevelopmental disorder with a strong genetic component. Co-occurrence of autism and chromosomal abnormalities is useful to localize candidate regions that may include gene(s) implicated in autism determinism. Several candidate chromosomal regions are known, but association of chromosome 22 abnormalities with autism is unusual. We report a child with autistic syndrome and a de novo 22q13.3 cryptic deletion detected by FISH. Previously described cases with 22q13.3 deletions shared characteristic developmental and speech delay, but autism was not specifically reported. This case emphasizes a new candidate region that may bear a gene involved in autism etiopathogenesis. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:839-844, 2000.

High-resolution integrated map encompassing the breast cancer loss of heterozygosity region on human chromosome 16q22.1.

Loss of heterozygosity (LOH) on the long arm of human chromosome 16 is a common genetic alteration observed in both invasive ductal and invasive lobular breast carcinomas. We have generated a high-resolution integrated map encompassing the smallest region of LOH overlap within chromosome 16q22.1 (SRO2). Southern hybridization experiments using more than 140 probes resulted in the assembly of 152 bacterial large-insert clones into a 2.8-Mb contig covering SRO2. The structure of the contig was verified by long-range mapping using total human genomic DNA, and the contig orientation was determined by fluorescence in situ hybridization. A total of 68 transcripts have been identified in the map. One of the genes residing within SRO2 is the E-cadherin gene, CDH1, which has previously been shown to be mutated in lobular breast carcinomas, resulting in loss of E-cadherin expression. In most cases of ductal carcinoma, which is the major mammary cancer type, E-cadherin is normally expressed, suggesting that other genes within 16q22.1 are involved in the development of this tumor subtype. The high-resolution map presented in this study provides a valuable resource for identification of tumor suppressor genes expected to be involved in the etiology of breast carcinomas.