Facile fabrication of activated charcoal decorated functionalized multi-walled carbon nanotube electro-catalyst for high performance quasi-solid state dye-sensitized solar cells

Memon, A.A.,Arbab, A.A.,Sahito, I.A.,Mengal, N.,Sun, K.C.,Qadir, M.B.,Choi, Y.S.,Jeong, S.H. Pergamon Press 2017 ELECTROCHIMICA ACTA Vol.234 No.-

<P>The proposed research presents significant progress in the photovoltaic performance of quasi-solid state dye-sensitized solar cells (DSSCs) by synthesizing a highly electro-catalytic active activated charcoal decorated functionalized multi-walled carbon nanotube (MWCNT) composite electro-catalyst as a counter electrode (CE). The proposed carbon composite structure was synthesize by facile acid functionalization of MWCNTs followed by the addition of mesoporous activated charcoal, decorating the tubular graphitic structure of the CNTs. The carbon composite paste deposited on FTO glass by a sequential process of doctor blade coating under an air-drying technique. The porous functionalized mesoporous carbon (f-MC) with a dominant oxygen rich surface displays greatly enhanced electrocatalytic activity, low charge transfer resistance (RCT), and exceptional cyclic stability as compared with pristine CNTs. The DSSC fabricated with f-MC CE demonstrated efficient electrochemical characteristics and photovoltaic performance when fabricated with a high-viscosity quasi-solid electrolyte. The highly conductive and porous carbon structure locates manifold sites for tri-iodide reduction reaction. High mobility of the quasi-solid electrolyte within defect rich (f-MC) surface confirmed a low RCT of (0.60 Omega. cm(2)), and exhibited superior electrocatalytic activity compared to a conventional platinum (Pt) reference CE. The f-MC CE based DSSCs showed high power conversion efficiency (PCE) of 8.42%, exceeding the Pt reference CE of 8.11%. Based on the facile synthesis of f-MC composites and fabrication of CE, the proposed DSSCs stand out as efficient next generation solar cells. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Fabrication of a flexible and conductive lyocell fabric decorated with graphene nanosheets as a stable electrode material

Mengal, N.,Sahito, I.A.,Arbab, A.A.,Sun, K.C.,Qadir, M.B.,Memon, A.A.,Jeong, S.H. Applied Science Publishers ; Elsevier Science Ltd 2016 Carbohydrate polymers Vol.152 No.-

Textile electrodes are highly desirable for wearable electronics as they offer light-weight, flexibility, cost effectiveness and ease of fabrication. Here, we propose the use of lyocell fabric as a flexible textile electrode because of its inherently super hydrophilic characteristics and increased moisture uptake. A highly concentrated colloidal solution of graphene oxide nanosheets (GONs) was coated on to lyocell fabric and was then reduced in to graphene nanosheets (GNs) using facile chemical reduction method. The proposed textile electrode has a very high surface conductivity with a very low value of surface resistance of only 40Ωsq<SUP>-1</SUP>, importantly without use of any binding or adhesive material in the processing step. Atomic force spectroscopy (AFM) and Transmission electron microscopy (TEM) were conducted to study the topographical properties and sheet exfoliation of prepared GONs. The surface morphology, structural characterization and thermal stability of the fabricated textile electrode were studied by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), X ray photon spectroscopy (XPS), Raman spectroscopy, Wide angle X ray diffraction spectroscopy (WAXD) and Thermogravimetric analysis (TGA) respectively. These results suggest that the GONs is effectively adhered on to the lyocell fabric and the conversion of GONs in to GNs by chemical reduction has no adverse effect on the crystalline structure of textile substrate. The prepared graphene coated conductive lyocell fabric was found stable in water and electrolyte solution and it maintained nearly same surface electrical conductivity at various bending angles. The electrical resistance results suggest that this lyocell based textile electrode (L-GNs) is a promising candidate for flexible and wearable electronics and energy harvesting devices.

Spatial distribution and sequential sampling plans for adult Sitona humeralis Stephens (Coleoptera: Curculionidae) in alfalfa

A. Arbab,M.R.McNeill 한국응용곤충학회 2014 Journal of Asia-Pacific Entomology Vol.17 No.3

The spatio-temporal distribution of adult Sitona humeralis Stephens (Coleoptera: Curculionidae), a key pest of alfalfa,was studied using sweep netting for two years in alfalfa fields. The first objective was to analyze the distributionof this insect within alfalfa and the second objectivewas to develop sampling plans based on fixed levels ofprecision for estimating S. humeralis adult populations. The following models were used to analyze the data:Taylor's power law and Iwao's patchiness regression. Our results document that in both years, Iwao's patchinessprovided a better description between variance and mean density. Taylor's b and Iwao's β were both significantlyN1, indicating that adults had aggregated spatial distribution. Iwao's α was significantly b0, indicating that thebasic distribution component of S. humeralis is the individual insect. Optimal sample sizes for fixed precisionlevels of 0.10 and 0.25 were estimated. The optimum sample size fluctuated throughout the seasons anddepended upon the weevil density and desired level of precision. This generally ranged from 3 to 7 × 15 sweepsand 16 to 46 × 15 sweeps to achieve precision levels of 0.25 and 0.10, respectively. With respect to the optimumsample size, the developed fixed-precision sequential sampling plans were suitable for estimatingweevil densityat a precision level of D= 0.25. The sampling plan presented here provides a tool for research on pest managementdecisions of S. humeralis.

Dentatin from Clausena excavata Induces Apoptosis in HepG2 Cells via Mitochondrial Mediated Signaling

Andas, A Reenaa Joys,Abdul, Ahmad Bustamam,Rahman, Heshu Sulaiman,Sukari, Mohd Aspollah,Abdelwahab, Siddig Ibrahim,Samad, Nozlena Abdul,Anasamy, Theebaa,Arbab, Ismail Adam Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.10

Hepatocellular carcinoma (HCC) is a primary liver cancer with high global incidence and mortality rates. Current candidate drugs to treat HCC remain lacking and those in use possess undesirable side effects. In this investigation, the antiproliferative effects of dentatin (DTN), a natural coumarin, were evaluated on HepG2 cells and DTN's probable preliminary molecular mechanisms in apoptosis induction were further investigated. DTN significantly (p<0.05) suppressed proliferation of HepG2 cells with an $IC_{50}$ value of $12.0{\mu}g/mL$, without affecting human normal liver cells, WRL-68 ($IC_{50}$ > $50{\mu}g/mL$) causing $G_0/G_1$ cell cycle arrest via apoptosis induction. Caspase colorimetric assays showed markedly increased levels of caspase-3 and caspase-9 activities throughout the treatment period. Western blotting of treated HepG2 cells revealed inhibition of $NF-{\kappa}B$ that triggers the mitochondrial-mediated apoptotic signaling pathway by up-regulating cytoplasmic cytochrome c and Bax, and down-regulating Bcl-2 and Bcl-xL. The current findings suggest DTN has the potential to be developed further as an anticancer compound targeting human HCC.

Synthesis of solution processed f-CNT@Bi₂S₃ hybrid film coated linen fabric as a free-standing textile structured photo catalyst

Memon, Anam Ali,Arbab, Alvira Ayoub,Patil, Supriya A.,Mengal, Naveed,Sun, Kyung Chul,Sahito, Iftikhar Ali,Jeong, Sung Hoon,Kim, Hak Sung Elsevier 2018 Applied catalysis. A, General Vol.566 No.-

<P><B>Abstract</B></P> <P>A unique metallic carbon hybrid film, synthesized with synchronized distribution of bismuth sulfide (Bi<SUB>2</SUB>S<SUB>3</SUB>) and exfoliated multiwall carbon nanotubes (MWCNTs), has been proposed for use as freestanding textile electrodes in photo catalysts. The defect-rich morphology of Bi<SUB>2</SUB>S<SUB>3</SUB> nanowire decorated MWCNT hybrid enhances the photocatalytic activity, electronic properties, cyclic stability, and electron pathways. The proposed f-CNT@Bi<SUB>2</SUB>S<SUB>3</SUB>-hybrid linen fabric electrode demonstrated a defect-rich morphology synchronized with high electrical conductivity. These properties greatly enhanced the photocatalytic activity and electron transfer. The high photocatalytic activity is attributed to the synergistic effect of the high electron affinity of MWCNTs and the structural distortion caused by Bi<SUB>2</SUB>S<SUB>3</SUB> nanowires. Degradation of methylene blue dye was accelerated owing to the elevated activity of Bi<SUB>2</SUB>S<SUB>3</SUB> nanowires, which provides fast absorption of contaminants and reduction of oxidative species. Our proposed system of metallic carbon freestanding textile electrode opens the broad applications of textile-based photochemical devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A flexible and highly conductive linen fabric is fabricated. </LI> <LI> The fabric is coated with carbon metallic films by doctor blade technique. </LI> <LI> The electrode is durable and highly photocatalytic active. </LI> <LI> The electrode is stable at various bending positions, against water and electrolyte. </LI> <LI> The surface resistance of the carbon metallic films coated fabric is only 19 Ω sq<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Definitive Closure of the Tracheoesophageal Puncture Site after Oncologic Laryngectomy: A Systematic Review and Meta-Analysis

Joseph M. Escandón,Arbab Mohammad,Saumya Mathews,Valeria P. Bustos,Eric Santamaría,Pedro Ciudad,Hung-Chi Chen,Howard N. Langstein,Oscar J. Manrique 대한성형외과학회 2022 Archives of Plastic Surgery Vol.49 No.5

Tracheoesophageal puncture (TEP) and voice prosthesis insertion following laryngectomy may fail to form an adequate seal. When spontaneous closure of the fistula tract does not occur after conservativemeasures, surgical closure is required. The purpose of this study was to summarize the available evidence on surgical methods for TEP site closure. A comprehensive search across PubMed, Web of Science, SCOPUS, and Cochrane was performed to identify studies describing surgical techniques, outcomes, and complications for TEP closure.We evaluated the rate of unsuccessful TEP closure after surgical management. A meta-analysis with a random-effect method was performed. Thirty-four studies reporting on 144 patients satisfied inclusion criteria. The overall incidence of an unsuccessful TEP surgical closure was 6% (95% confidence interval [CI] 1–13%). Subgroup analysis showed an unsuccessful TEP closure rate for silicone button of 8% (95% CI<1–43%), 7% (95% CI<1–34%) for dermal graft interposition,<1% (95%CI<1–37%) for radial forearm free flap,<1% (95% CI<1–52%) for ligation of the fistula, 17% (95% CI<1–64%) for interposition of a deltopectoral flap, 9% (95% CI<1– 28%) for primary closure, and 2% (95% CI<1–20%) for interposition of a sternocleidomastoid muscle flap. Critical assessment of the reconstructive modality should take into consideration previous history of surgery or radiotherapy. Nonirradiated fields and small defects may benefit fromfistula excision and tracheal and esophagealmultilayer closure. In cases of previous radiotherapy, local flaps or free tissue transfer yield high successful TEP closure rates. Depending on the defect size, sternocleidomastoid muscle flap or fasciocutaneous free flaps are optimal alternatives.