Enhancement of magnetoresistance in manganite multilayers

Magnanite multilayers have been fabricated using La0.67Ca0.33MnO3 as the ferromagnetic layer and Pr0.7Ca0.3MnO3 and Nd0.5Ca0.5MnO3 as the spacer layers. All the multilayers were grown on LaAlO3 (100) by pulse laser deposition. An enhanced magnetoresistnace (defined (RH- R0)/R0) of more than 98% is observed in these multilayers. Also a low field magnetoresistance of 41% at 5000 Oe is observed in these multilayer films. The enhanced MR is attributed to the induced double exchange in the spacer layer, which is giving rise to more number of conducting carriers. This is compared by replacing the spacer layer with LaMnO3 where Mn exists only in 3+ state and no enhancement is observed in the La0.67Ca0.33MnO3 / LaMnO3 multilayers as double exchange mechanism can not be induced by external magnetic fields.Comment: 13 pages, 5 Figure

New Convertible Authenticated Encryption Scheme with Message Linkages

The digital signature provides the signing message with functions like authentication, integration and non-repudiation. However, in some of the applications, the signature has to be verified only by specific recipients of the message and it should be hidden from the public. For achieving this, authenticated encryption systems are used. Authenticated Encryption schemes are highly helpful to send a confidential message over an insecure network path. In order to protect the recipients benefit and for ensuring non-repudiation, we help the receiver to change the signature from encrypted one to an ordinary one. With this we avoid any sort of later disputes. Few years back, Araki et al. has proposed a convertible authenticated scheme for giving a solution to the problem. His scheme enables the recipient to convert the senders signature into an ordinary one. However, the conversion requires the cooperation of the signer. In this thesis, we present a convertible authenticated encryption scheme that can produce the ordinary signature without the cooperation of the signer with a greater ease. Here, we display a validated encryption plan using message linkages used to convey a message. For the collector's advantage, the beneficiary can surely change the encrypted signature into an ordinary signature that which anyone can check. A few attainable assaults shall be examined, and the security investigation will demonstrate that none of the them can effectively break the proposed plan

A new species of Marsdenia R. Br. (Asclepiadaceae) from South India

Marsdenia raziana which represents a new species of Asclepiadaceae, collected around Yelnir ghats forests (W. ghats), Samse, Chikmagalur District, has been described and illustrated

Dietary vitamin E and physical exercise: I. Altered endurance capacity and plasma lipid profile in ageing rats

The effect of vitamin E on the exercise performance and plasma lipid profile was studied in male Wistar rats of 4-(young adults), 8-(old adults), 12-(middle-age) and 22-months (old) of age. Animals were orally supplemented with vitamin E and allowed to swim for 30min/day, 5 days/week and for a total period of 60 days. Swim velocity (Sv), external work done (Wext) and endurance (E) capacity were the parameters that were used to assess the exercise performance of the trained rats that were either supplemented or non-supplemented with the dietary antioxidant. Plasma lipid profile analyses were in terms of low-density lipoprotein (LDL-C), high-density lipoprotein, (HDL-C) cholesterol and total cholesterol (C). Age-related decline in Sv was noticeable in the 22-months old rats. However, the effect of vitamin E on the Sv between the trained groups was not evident in any of the age groups. Wext increased linearly with age with no significant variations between the trainees. Trainee rats, when allowed to swim to exhaustion, showed a higher endurance capacity when supplemented with vitamin E. However, this capacity declined with age. There was a significant age-associated elevation in plasma C with corresponding increase in LDL-C. Exercise training in conjunction with vitamin E supplementation was most effective in elevating HDL-C levels in all age groups. These changes were accompanied by significant reductions in cholesterol/HDL-C ratios in animals receiving vitamin E, sedentary or otherwise. Our data suggests that it may be important to consider vitamin E while attempting to derive the benefits of swim training, both in terms of favorably altering the plasma lipid profile as well as enhancing the endurance capacity of exercise trainees. Dietary supplementation by vitamin E could attenuate the early onset of fatigue in the old. © 2002 Elsevier Science Inc. All rights reserved

Dietary vitamin E and physical exercise: II. Antioxidant status and lipofuscin-like substances in aging rat heart

The heart faces a high risk of free radical injury owing to a slow generation of antioxidant (AO) enzymes by its cells. A general decline in this system may be another reason for the development of age-related diseases. Although the correlation between aging and exercise has been studied extensively, these studies have produced conflicting data on the effects of vitamin E on the aging heart, when it is introduced as an intervening factor. To investigate these effects, we determined the activities of antioxidant enzymes (AOEs) such as superoxide dismutase (SOD) and catalase (CAT), lipid peroxidation (LP), lipofuscin (LF)-like autofluorescent substances and vitamin E content in the left and right ventricles (LV and RV) of the heart in male Wistar albino rats of 4-(young adults), 8-(old adults), 12-(middle-age) and 22-mos(old) of age. Animals were orally supplemented with vitamin E and allowed to swim for 30min/day, 5 days/week and for a total period of 60 days. Exercise training in all the age groups except the old was effective in upregulating the SOD activity. Old trainees showed an increase in SOD activity when supplemented with vitamin E. In the 22-mo-olds, a remarkable decrease in CAT activity was seen. Exercise by itself upregulated the CAT as well as SOD activity in all age groups except the old wherein vitamin E was effective in increasing the activities of AOEs. Supplementation significantly reduced LP as evidenced by lowered malondialdehyde (MDA) and LF-like autofluorescent substances in the trained as well as sedentary rats. Tissue vitamin E content was low in the swim trainees that were not supplemented. This change, well emphasized in the trainee groups of 22-mo-old suggests the probable utilization of vitamin E in keeping free radicals at bay. Our results suggest that vitamin E can stand out as a significant tool in ameliorating the declining AO defense in the old rats. © 2002 Elsevier Science Inc. All rights reserved

5-(4-Chloro­phen­yl)-1-methyl-3-oxocyclo­hexa­necarbonitrile

In the title mol­ecule, C14H14ClNO, the cyclo­hexane ring adopts a chair conformation. The cyano group and the methyl group have axial and equatorial orientations, respectively. The benzene ring has an equatorial orientation. A C—H⋯π inter­action involving the benzene ring is found in the crystal structure

C-band superconductor/semiconductor hybrid field-effect transistor amplifier on a LaAlO3 substrate

A single-stage C-band superconductor/semiconductor hybrid field-effect transistor amplifier was designed, fabricated, and tested at 77 K. The large area (1 inch x 0.5 inches) high temperature superconducting Tl-Ba-Ca-Cu-O (TBCCO) thin film was rf magnetron sputtered onto a LaAlO3 substrate. The film had a transition temperature of about 92 K after it was patterned and etched. The amplifier showed a gain of 6 dB and a 3 dB bandwidth of 100 MHz centered at 7.9 GHz. An identical gold amplifier circuit was tested at 77 K, and these results are compared with those from the hybrid amplifier

Evaluating Penetration Ability of \u3ci\u3ePlodia interpunctella\u3c/i\u3e (Hübner) (Lepidoptera: Pyralidae) Larvae into Multilayer Polypropylene Packages

The larvae of the Indian meal moth, Plodia interpunctella (Hübner), can invade or penetrate packaging materials and infest food products. Energy bars with three polypropylene packaging types were challenged with eggs (first instars), third instars, and fifth instars of P. interpunctella to determine package resistance at 28 °C and 65% r.h. The packing types were also challenged with two male and two female pupae of P. interpunctella under similar conditions in order to determine which package provided the greatest protection against larval penetration. Samples infested with eggs, third instars, and pupae were evaluated after 21 days and 42 days to count the number of larvae, pupae, and adults found inside the packages. Packages challenged with fifth instars were observed after 21 days to count the number of larvae, pupae, and adults inside each package. The number and diameter of the holes were determined in each package, followed by the amount of damage sustained to the energy bar. Third and fifth instars showed a higher tendency to penetrate all of the packaging types. First instars showed a reduction in package penetration ability compared with third and fifth instars. The increase in exposure time resulted in an increase in the damage sustained to the energy bars. Among packaging types, the thickest package (Test A) was most resilient to penetration by all of the larval stages. In conclusion, energy bar manufacturers need to invest more effort into improving packaging designs, creating thicker gauge films, or advancing odor barrier technology, in order to prevent penetration and infestation by P. interpunctella larvae