Characterization of Hydride-Based Silica and Diamond Hydride Stationary Phases

Aqueous normal phase chromatography possesses characteristics of both normal phase (NP) and also reverse phase (RP) chromatography. It can retain polar as well as non-polar compounds by carefully selecting the concentration ratio of organic solvent to water in the mobile phase. Silica hydride columns contain only a small percentage of silanol groups which are polar in nature and have an effect on the separation process. Diamond hydride columns consist of a small amount (~2%) of carbon chemically bonded to a silica hydride surface. This research work characterized both hydride-based silica and diamond hydride stationary phases under isocratic and gradient conditions. Both columns were compared using the same conditions, and their efficiencies and symmetries were calculated. Diamond hydride showed different selectivity than the silica hydride column because of the 2% carbon on the silica hydride surface. This research work shows that both the silica hydride and diamond hydride columns can be used in aqueous normal phase conditions

Classical and quantum massive cosmology for the open FRW universe

In an open Friedmann-Robertson-Walker (FRW) space background, we study the classical and quantum cosmological models in the framework of the recently proposed nonlinear massive gravity theory. Although the constraints which are present in this theory prevent it from admitting the flat and closed FRW models as its cosmological solutions, for the open FRW universe, it is not the case. We have shown that, either in the absence of matter or in the presence of a perfect fluid, the classical field equations of such a theory adopt physical solutions for the open FRW model, in which the mass term shows itself as a cosmological constant. These classical solutions consist of two distinguishable branches: One is a contacting universe which tends to a future singularity with zero size, while another is an expanding universe having a past singularity from which it begins its evolution. A classically forbidden region separates these two branches from each other. We then employ the familiar canonical quantization procedure in the given cosmological setting to find the cosmological wave functions. We use the resulting wave function to investigate the possibility of the avoidance of classical singularities due to quantum effects. It is shown that the quantum expectation values of the scale factor, although they have either contracting or expanding phases like their classical counterparts, are not disconnected from each other. Indeed, the classically forbidden region may be replaced by a bouncing period in which the scale factor bounces from the contraction to its expansion eras. Using the Bohmian approach of quantum mechanics, we also compute the Bohmian trajectory and the quantum potential related to the system, which their analysis shows are the direct effects of the mass term on the dynamics of the universe.Comment: 18 pages, 7 figures, typos corrected, refs. adde

The String Landscape, Black Holes and Gravity as the Weakest Force

We conjecture a general upper bound on the strength of gravity relative to gauge forces in quantum gravity. This implies, in particular, that in a four-dimensional theory with gravity and a U(1) gauge field with gauge coupling g, there is a new ultraviolet scale Lambda=g M_{Pl}, invisible to the low-energy effective field theorist, which sets a cutoff on the validity of the effective theory. Moreover, there is some light charged particle with mass smaller than or equal to Lambda. The bound is motivated by arguments involving holography and absence of remnants, the (in) stability of black holes as well as the non-existence of global symmetries in string theory. A sharp form of the conjecture is that there are always light "elementary" electric and magnetic objects with a mass/charge ratio smaller than the corresponding ratio for macroscopic extremal black holes, allowing extremal black holes to decay. This conjecture is supported by a number of non-trivial examples in string theory. It implies the necessary presence of new physics beneath the Planck scale, not far from the GUT scale, and explains why some apparently natural models of inflation resist an embedding in string theory.Comment: 20 pages, LaTeX, 5 EPS figures; v2: minor correction

Ethnobotany of the Monpa ethnic group at Arunachal Pradesh, India

<p>Abstract</p> <p>Background</p> <p>The present paper documents the uses of plants in traditional herbal medicine for human and veterinary ailments, and those used for dietary supplements, religious purpose, local beverage, and plants used to poison fish and wild animals. Traditional botanical medicine is the primary mode of healthcare for most of the rural population in Arunachal Pradesh.</p> <p>Materials and methods</p> <p>Field research was conducted between April 2006 and March 2009 with randomly selected 124 key informants using semi-structured questionnaire. The data obtained was analyzed through informant consensus factor (F_IC) to determine the homogeneity of informant's knowledge on medicinal plants.</p> <p>Results</p> <p>We documented 50 plants species belonging to 29 families used for treating 22 human and 4 veterinary ailments. Of the medicinal plants reported, the most common growth form was herbs (40%) followed by shrubs, trees, and climbers. Leaves were most frequently used plant parts. The consensus analysis revealed that the dermatological ailments have the highest F_IC(0.56) and the gastro-intestinal diseases have F_IC(0.43). F_ICvalues indicated that there was high agreement in the use of plants in dermatological and gastro-intestinal ailments category among the users. <it>Gymnocladus assamicus </it>is a critically rare and endangered species used as disinfectant for cleaning wounds and parasites like leeches and lice on livestocks. Two plant species (<it>Illicium griffithii </it>and <it>Rubia cordifolia</it>) are commonly used for traditional dyeing of clothes and food items. Some of the edible plants recorded in this study were known for their treatment against high blood pressure (<it>Clerodendron colebrookianum</it>), diabetes mellitus (<it>Momordica charantia</it>), and intestinal parasitic worms like round and tape worms (<it>Lindera neesiana</it>, <it>Solanum etiopicum</it>, and <it>Solanum indicum</it>). The Monpas of Arunachal Pradesh have traditionally been using <it>Daphne papyracea </it>for preparing hand-made paper for painting and writing religious scripts in Buddhist monasteries. Three plant species (<it>Derris scandens</it>, <it>Aesculus assamica</it>, and <it>Polygonum hydropiper</it>) were frequently used to poison fish during the month of June-July every year and the underground tuber of <it>Aconitum ferrox </it>is widely used in arrow poisoning to kill ferocious animals like bear, wild pigs, gaur and deer. The most frequently cited plant species; <it>Buddleja asiatica </it>and <it>Hedyotis scandens </it>were used as common growth supplements during the preparation of fermentation starter cultures.</p> <p>Conclusion</p> <p>The traditional pharmacopoeia of the Monpa ethnic group incorporates a myriad of diverse botanical flora. Traditional knowledge of the remedies is passed down through oral traditions without any written document. This traditional knowledge is however, currently threatened mainly due to acculturation and deforestation due to continuing traditional shifting cultivation. This study reveals that the rural populations in Arunachal Pradesh have a rich knowledge of forest-based natural resources and consumption of wild edible plants is still an integral part of their socio-cultural life. Findings of this documentation study can be used as an ethnopharmacological basis for selecting plants for future phytochemical and pharmaceutical studies.</p