Graphene overcoats for ultra-high storage density magnetic media.

Hard disk drives (HDDs) are used as secondary storage in digital electronic devices owing to low cost and large data storage capacity. Due to the exponentially increasing amount of data, there is a need to increase areal storage densities beyond ~1 Tb/in2. This requires the thickness of carbon overcoats (COCs) to be <2 nm. However, friction, wear, corrosion, and thermal stability are critical concerns below 2 nm, limiting current technology, and restricting COC integration with heat assisted magnetic recording technology (HAMR). Here we show that graphene-based overcoats can overcome all these limitations, and achieve two-fold reduction in friction and provide better corrosion and wear resistance than state-of-the-art COCs, while withstanding HAMR conditions. Thus, we expect that graphene overcoats may enable the development of 4-10 Tb/in2 areal density HDDs when employing suitable recording technologies, such as HAMR and HAMR+bit patterned media.

Effect of Solanum nigrum and Ricinus communis extracts on histamine and carrageenan-induced inflammation in the chicken skin.

We studied anti-inflammatory effect of ethanolic extract of Solanum nigrum leaves and Ricinus communis root bark using chicken skin as model. Leaves of these plants were dried under shade and powdered. 5% Ethanol extracts were prepared using Soxhlet and injected intraperitoneally (400 mg/kg) 1 hour prior to the induction of inflammation. Inflammatory lesion were induced by intradermal injection of 0.02 ml 0.05%w/v histamine (0-2 min, 15 min, 30 min, 1 hr and 6 hr) and 1% w/v carrageenan (0-2 min, 30 min, 1 hr, 6 hr, 12 hr and 48 hr) in different group of birds. Increase in vascular permeability was studied using Evans blue as a permeability marker both qualitatively and quantitatively. Cellular events were studied in skin lesions at various time intervals and cells were counted at high power objective under microscope. Both, extracts exhibited significant decrease in permeability response at an early stage (0-2 min) of histamine as well as in carrageenan induced inflammatory lesions. There was a significant (p< 0.05) suppression in the emigration of heterophils, monocytoid cells, basophils and total leukocytosis in Solanum nigrum and Ricinus communis pretreated chicken skin lesions as compared to the control. The present study suggested antihistamine and anti-inflammatory properties of ethanolic extract of Solanum nigrum and Ricinus communis.

Synergistic effect of polymer encapsulated silver nanoparticle doped WS2 sheets for plasmon enhanced 2D/3D heterojunction photodetectors.

Chemical doping and plasmonic enhanced photoresponsivity of two dimensional (2D) n-WS2/p-Si heterojunctions are demonstrated for the first time. Novel PVP coated Ag0 intercalation induced synthesis has led to the formation of impurity-free, chemically doped few-layer n-WS2 with reversed conductivity following the Maxwell-Wagner-Sillars interfacial effect. The resultant composite film exhibits excellent stability and tunable plasmonic absorption due to silver nanoparticles of different sizes. A sharp band-edge absorption of the hybrid material indicates the presence of spin-orbit coupled direct band gap transitions in WS2 layers, in addition to a broader plasmonic peak attributed to Ag nanoparticles. Stabilized Ag-nanoparticle (∼4-6 nm) embedded electron rich n-WS2 has been used to fabricate plasmon enhanced, silicon compatible heterojunction photodetectors. The detectors exhibited superior properties, possessing a photo-to-dark current ratio of ∼103, a very high responsivity (8.0 A W-1) and an EQE of 2000% under 10 V bias with a broad spectral photoresponse in the wavelength range of 400-1100 nm. The results provide a new paradigm for intercalant impurity-free metal nanoparticle assisted exfoliation of n-type few-layer WS2, with the nanoparticles playing a dual role towards the realization of 2D materials based broadband heterojunction optoelectronic devices by inducing chemical doping as well as tunable plasmon enhanced absorption.

Histopathological changes in liver, kidney and muscles of pesticides exposed malnourished and diabetic rats.

Histopathological changes were observed in liver, kidney and muscles of normal, protein-malnourished, diabetic as well as both protein-malnourished and diabetic albino rats when exposed to a mixture of monocrotophos, hexachlorocyclohexane and endosulfan at varying intervals. The examination revealed hepatotoxic, nephrotoxic and muscular necrotic effects in pesticides exposed rats. Toxicity was aggravated in protein-malnourished and diabetic animals and more so, if the animals were both diabetic and protein-malnourished.

Attempted induction of local Shwartzman reaction in the chicken.

Chickens and rabbits were injected intradermally with an endotoxin, namely Escherichia coli lipopolysaccharide (LPS). Twenty-four hours later, LPS was again administered intravenously to induce a local Shwartzman reaction. A typical cutaneous inflammatory reaction developed in rabbits, but not in chickens. Even very high doses of LPS, that made the birds visibly sick, failed to elicit the reaction. The results suggest that chickens are refractory to the Shwartzman reaction. A noteworthy feature of the chickens' response to intradermal endotoxin was the formation of prominent perivascular lymphoid aggregates.

Increased vascular permeability and leucocyte emigration in Escherichia coli endotoxin injury in the chicken skin.

The permeability response was examined in chickens following intradermal injection of Escherichia coli endotoxin. The 'dye' and 'colloidal carbon' techniques were employed. The endotoxin evoked a monophasic response of immediate-prolonged type. The increase in vascular permeability was confined to venules and small veins only, indicating its mediation by endogenous permeability factors. The carbon labelling exhibited arboreal, disjointed and rectangular to hexagonal patterns. Histologically, a striking feature of the reaction was an accumulation of basophils in unusually large numbers. No other type of stimulus appears to induce basophilic response of a similar magnitude in the chicken. The results suggest that endotoxin, being a bacterial product, may exert a chemotactic effect on basophils. Hyperaemia, oedema, necrosis and formation of perivascular lymphoid aggregates were also recognised.

Pathology of inflammatory-reparative response in punched wounds of the chicken skin.

Vascular and cellular responses were examined sequentially in punched wounds of the chicken skin. The 'dye' and the 'colloidal carbon' technique revealed that the increased permeability response was immediate and sustained. The response attained its peak at 1 hour and persisted for up to 6 hours, but the increased permeability was prolonged over a period of 48 h. The increase in vascular permeability at all stages was confined to venules and small veins only. In the later stages of healing, the newly formed vessels in the granulation tissue were leaky. The initial migration of leukocytes comprised heterophils and monocytoid cells. This was soon followed by infiltration of some basophils. A striking feature of the reaction, in the granulation tissue, was that the monocytoid cells apparently coalesced, formed syncytia, and even what appeared to be distinct multinucleated giant cells. Whereas mast cells participated in the early stages, they were absent in the granulation tissue. Proliferation of the fibroblasts began around 18 h, angiogenesis and re-epithelialization at 3 days, and the healing was complete by about 7 days.

Studies on the cellular response in avian inflammation using a simple subcutaneous pouch model.

A subcutaneous pouch model was developed and used for examination of cellular events in the local acute inflammatory response in the chicken. The model involved insertion of a pair of coverslips-dipped in the irritant-into the prepared subcutaneous pouch, and their replacement with plain coverslips at frequent intervals. The model was simple to operate, caused minimal distress to the experimental bird, and permitted multiple continual sampling of emigrating cells. The cytological features and migratory sequence of inflammatory cells produced by non-immunological and immunological stimuli were studied over a period of 48 h. The initial migration of leukocytes comprised heterophils and monocytes. This was soon followed by emigration of basophils. The basophilic reaction was pronounced in response to Escherichia coli endotoxin. Lymphocytes were prominent in the later stages. Also, in the later stages the monocytes apparently coalesced, formed syncytia and even what appeared to be distinct multinucleated giant cells. The results obtained by the present model corroborated the findings of earlier investigators recorded through the use of tissue sections and impression smears. It is suggested that the subcutaneous pouch model may offer an excellent system in avian inflammation research.

Ventricular intussusception in a domestic fowl.

Necropsy of a 12-week-old female chicken revealed invagination of proventriculus into the gizzard with eversion of the former.

The avian inflammatory-reparative response: adaptation and utilization of a tissue cage model.

A tissue cage model was adapted and utilized for examination of the inflammatory-reparative response in the chicken. The model involved insertion of a polyethylene cage, soaked in the irritant, into the previously prepared subcutaneous pouch. Using this model the cellular events in the fibrovascular granulation tissue in response to turpentine, concanavalin-A and Escherichia coli endotoxin were studied. It was concluded that the tissue cage model worked well in the chicken and that it can be useful in studies relating to the inflammatory-reparative response.

Effects of anti-inflammatory drugs on increased vascular permeability in acute inflammatory response in the chicken.

The effects of anti-inflammatory drugs were examined on the turpentine-induced acute inflammatory response in the chicken skin. An increase in vascular permeability was evaluated using the 'dye' technique. Although histamine and 5-hydroxytryptamine (5-HT) appeared to be the major mediators of the permeability response in the early phase, involvement of 5-HT was more significant. Use of other anti-inflammatory drugs suggested mediation of the permeability response also through the release of prostaglandins or leukotrienes, or both.