Fabrication of sensitive bioelectrode based on atomically thin CVD grown graphene for cancer biomarker detection.

Motivation behind the present work is to fabricate a cost effective and scalable biosensing platform for an easy and reliable detection of cancer biomarker Carcinoembryonic antigen (CEA). Here, we report the sensitive and selective detection of CEA using graphene based bio-sensing platform. Large sized (~ 2.5 × 1.0cm2), uniform, continuous, single and few layers graphene films have been grown on copper (Cu) substrate employing chemical vapor deposition (CVD) technique using hexane as a liquid precursor. Functional group has been created over Graphene/Cu substrate through π-π stacking of 1- pyrenebutanoic acid succinimidyl ester (PBSE). Further, to make the sensor specific to CEA, antibody of CEA (anti-CEA) has been covalently immobilized onto PBSE/Graphene/Cu electrode. Selective and sensitive detection of CEA is achieved by anti-CEA/PBSE/Graphene/Cu electrode through electrochemical impedance spectroscopy (EIS) measurements. Under optimal condition, the fabricated sensor shows linear response in the physiological range 1.0-25.0ngmL-1 (normal value ~ 5.0ngmL-1), revealing sensitivity 563.4Ωng-1mLcm-2 with a correlation coefficient of 0.996 and limit of detection (LOD) 0.23ngmL-1. In this way, one step electrode fabrication with high specific surface area provides a light weight, low cost, reliable and scalable novel biosensing platform for sensitive and selective detection of CEA. We believe that this bioelectrode equipped with specific recognition elements could be utilized for detection of other biomolecules too.

Formation of nano-quasicrystalline decagonal phase in the Al70Cu10Co5Ni15 system by high energy ball milling.

A nano decagonal quasicrystalline phase in the Al70Cu10Co5Ni15 alloy has been synthesized by mechanical alloying of a mixture of elemental powders followed by annealing. A high-energy ball milling of the elemental mixture of Al, Cu, Co and Ni leads to the formation of B2 type quaternary intermetallic alloys. The X-ray diffraction and transmission electron microscopy techniques have been employed for characterization of the samples. It was observed that the dissolution of the individual elements into an alloy led to the formation of a nano B2 phase. This phase was found to be quite stable against milling and no other crystalline or amorphous phases could be detected. Milled powder after annealing at 700 degrees C for 60 h was found to transform to nano-decagonal phase. Attempts have been made to understand the evolution of the complex intermetallic nano phases and their relative stability during milling.

Small amplitude ion-acoustic double layers in multicomponent plasma with positrons.

Ion-acoustic double layers has been studied in multicomponent plasma with positrons. Using the reductive perturbation method, the modified Korteweg-de Vries (mKdV) equation is derived for the system. The double-layer solution of the mKdV equation is discussed in detail. It is found that there exist two critical concentrations of positrons, alphaR and alphaQ, which decide the existence and nature of the ion-acoustic double layers. It is also found that the system supports ion-acoustic double layers only when the positron concentration (alpha) is less than the critical concentration alphaR (i.e., alphaalphaQ, the system supports rarefactive double layers for alphaalphaQ, compressive double layers exist. The present theory also predicts that for a given set of parameter values on increasing the positron concentration, the amplitude of the rarefactive (compressive) double layer decreases (increases), whereas as positron concentration is increased, the width of the rarefactive (compressive) double layer increases (decreases). The effects of positron concentration and temperature ratio on the characteristics of the double layers (namely amplitude and width) are discussed in detail.

Synthesis of zinc oxide nanotetrapods and nanorods by thermal evaporation without catalysis.

ZnO nanotetrapods and nanorods have been synthesized by a simple thermal evaporation of Zn powder (300 mesh, 99.99% purity) under simultaneous flow of oxygen and argon gases in two-zone furnace in two different temperature regions. These ZnO nanostructures have hexagonal structure, which grow along the [001] direction in the form of nanotetrapods (diameter approximately 60-150 nm, length approximately 1-4 microm) and nanorods (diameter approximately 30-60 nm, length approximately 2-5 microm). The morphologies of these ZnO nanostructures have been investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It has been found that growth parameters like temperature, gas flow rate etc., control the diameter of the nanotetrapods and nanorods. These novel structures of ZnO nanorods and nanotetrapods may be attractive for optical and other nanodevices.

Synthesis of nanocrystalline (Co, Ni)Al2O4 spinel powder by mechanical milling of quasicrystalline materials.

In the present study, attempts have been made to synthesize the nano-crystalline (Co, Ni)Al2O4 spinel powders by ball milling and subsequent annealing. An alloy of Al70Co15Ni15, exhibiting the formation of a complex intermetallic compound known as decagonal quasicrystal is selected as the starting material for mechanical milling. It is interesting to note that this alloy is close to the stoichiometry of aluminum and transition metal atoms required to form the aluminate spinel. The milling was carried out in an attritor mill at 400 rpm for 40 hours with ball to powder ratio of 20 : 1 in hexane medium. Subsequent to this annealing was performed in an air ambience for 10, 20, and 40 h at 600 degrees C in side the furnace in order to oxidize the decagonal phase and finally to form the spinel structure. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the formation of nano-sized decagonal phase after milling and then (Co, Ni)Al2O4 spinel type phase after annealing. The XRD studies reveal the lattice parameter to be 8.075 angstroms and the lattice strain as 0.6%. The XRD and TEM explorations of spinel phase indicate the average grain size to be approximately 40 nm.

Nasal mucociliary clearance in health and disease.

"Standard saccharine test is used to detect nasal mucociliary clearance time in healthy individuals both adults and children. The length of the nose was measured radiologically and with the help of a soft malleable rubber catheter. For healthy individuals, mean nasal mucociliary clearance lime is 8.2 minutes in children and 9.5 minutes in adults. The mean nasal mucociliary clearance rates were 11.1 mm/min for children and 12.7 mm/min for adults.Deviated nasal septum, chronic sinusitis, allergic rhinitis, atrophic rhinitis, chronic smokers and patients with recent nasal packings were taken as diseased conditions in adults, whereas children with adenoid hyperplasia were taken for the study. In all of these, nasal mucociliary clearance was significantly prolonged."

Nucleation and growth of catalyst-free zinc oxide nanostructures.

This paper deals with the investigations on the nucleation and growth of Zinc Oxide (ZnO) nanostructures in a catalyst free synthesis. The ZnO nanostructures have been formed by evaporation of Zn (99.99%) in O2 and Ar atmosphere in single zone furnace under two temperature regions, region A (approximately 1173-1073 K) and region B (approximately 873-773 K). Through application of XRD and TEM techniques, it has been shown that first ZnO is formed which changes to ZnOx through creation of oxygen vacancies. The ZnOx acts as self-catalyst and leads to formation of various nanostructures. Those observed in the present investigation are nanotetrapods (1 D, diameter approximately 70-450 nm, length approximately 2-4.5 approximatelym) nanorods (1 D, diameter approximately 45-95 nm, length approximately 2.5-4.5 microm), nanoflowers(2D, central core diameter approximately 90-185 nm, length of petals/nanorod approximately 1.0-3.5 microm) and nanoparticles (3D, size approximately 0.85-2.5 microm). These nanostructures have been revealed by SEM explorations. Attempts have been made to explain the formation of the various nanostructures in terms of the creation and distribution of the ZnOx, the temperature as well as oxygenation conditions.

Nasopharyngeal angiofibroma (a report of 19 cases).

Nasopharyngeal Angiofibroma is a relatively rare benign, but locally aggresive tumor of the nasopharynx afflicting the adolescent males. The management of these tumors has been a subject of much interest and controversy in the past Here we present a series of 19 patients of nasopharyngeal angiofibroma (with CT Scan as the main stay of diagnosis) managed over the last 5 years at ENT and Head & Neck Surgery Department of S.S.G. Hospital, Vadodara, with infraoperative internal maxillary artery ligation via the trans maxillary approach permitting accurate removal of tumor with no major post operative complications, minimal blood loss, good cosmetic result and no recurrence till date. If further experience with this approach to management in a larger series of patients has the same results, surgery should be the gold standard in treatment of Nasopharyngeal angiofibroma.

Diagnostic role of ultrasonography in neck swellings.

Diagnostic Role of Ultrasonography in Neck Swellings The study of ultrasonographic features of various neck swellings in fifty patients was done. There were 22 thyroid and thyroid related swelling, 8 salivary gland lesions, 9 lymph nodes and 14 swellings of miscellaneous origin. Various ultrasonographic features like echogenicity, echotextures were noted. There were no specific echogenicity in benign and malignant thyroid neoplasms. Various ultrasonographic features of benign and malignant salivary neoplasms and lymph nodes are described. Specific sonographic features of various miscellaneous neck swellings are also described.

Children with glue ear: how do they present?

A prospective study examined 280 children aged between 2 and 11 years with mild or severe forms of otitis media with effusion (OME). There was a 2-year delay between the first suspicion of hearing loss and presentation to an otolaryngologist. In approximately 50% of these children hearing loss was first suspected by the mother and in 20-30% detection was by routine screening tests. In most cases actual hearing loss was the subjective presenting feature, but in others, speech, language or learning difficulties heralded the problem. It is suggested that such data might be incorporated into a questionnaire for parents which may then be used to assess parental ability to detect hearing loss due to otitis media with effusion in small children.