A sparse graph almost as good as the complete graph on points inK dimensions

A setV ofn points ink-dimensional space induces a complete weighted undirected graph as follows. The points are the vertices of this graph and the weight of an edge between any two points is the distance between the points under someL _p metric. Let ε≤1 be an error parameter and letk be fixed. We show how to extract inO(n logn+ε ^−k log(1/ε)n) time a sparse subgraphG=(V, E) of the complete graph onV such that: (a) for any two pointsx, y inV, the length of the shortest path inG betweenx andy is at most (1+∈) times the distance betweenx andy, and (b)|E|=O(ε^−k n).     

Synthesis of substituted pyrimidine using ZnFe2O4 nanocatalyst via one pot multi-component reaction ultrasonic irradiation

A highly efficient, eco-friendly, recyclable heterogeneous ZnFe₂O₄ nanocatalyzed synthesis of 2-amino-4-substituted 1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitrile (4a-j) derivatives via one pot multicomponent reaction of benzimidazole ( 1 ), substituted aromatic aldehyde ( 2a-j ) and malononitrile ( 3 ) under ultrasonic irradiations. Significance of this synthetic approach is short reaction time, easy handling, simplicity, efficiency, high yield, and recoverable catalyst.     

Preparation of ammonia borane in high yield and purity, methanolysis, and regeneration

Ammonia borane (AB) is emerging as a promising solid hydrogen carrier, particularly for power generation in portable devices that employ proton-exchange membrane fuel cells. A preparative-scale synthesis of AB from sodium borohydride and ammonium salts in high yields (> or =95%) and very high purity (> or =98%) has been described. The first systematic study of a transitional metal-catalyzed alcoholysis of AB, comparison of the methanolysis to the hydrolysis of AB, and regeneration of AB from ammonium tetramethoxyborate also has been described.     

Effect of myricetin on deoxycorticosterone acetate (DOCA)-salt-hypertensive rats

Chronic administration of myricetin (100 and 300?mg?kg?1, p.o., for 4 weeks) isolated from Vitis vinifera (Vitaceae) ameliorated hypertension and oxidative stress induced by deoxycorticosterone acetate (DOCA)-salt in rats. Myricetin treatment reduced systolic blood pressure, vascular reactivity changes and reversed the DOCA-induced increase in heart rate. Urinary sodium excretion was significantly decreased in animals treated with myricetin compared to the DOCA group when measured by flame photometer. The cumulative concentration response curve of serotonin (5-HT) and angiotensin II (Ang II) were shifted towards the right in rats treated with myricetin using the isolated rat fundus strip and ascending colon, respectively. Increased levels of thiobarbituric acid reactive substances and decreased levels of superoxide dismutase, catalase and reduced glutathione in the heart tissue were observed in animals treated with DOCA, which were reversed by myricetin. Thus, myricetin shows antihypertensive and antioxidant properties in the DOCA model of hypertension.     

Advantages of a soft protective layer for good signal-to-noise ratio proton radiographs in high debris environments

Proton radiography is a very powerful diagnostic but in some high debris environments it may be challenging to get a good signal-to-noise ratio radiograph to gain insights into the electric and magnetic field topology, and thus the basic physics. Such environments are produced for example on z-pinches and also on lasers such as the National Ignition Facility. We demonstrate here the feasibility of clean, very high signal-to-noise ratio proton radiographs in extremely hostile environments.     

Novel and Efficient Synthesis of tert-Butyl-2-(4-(2-aminoethyl)phenylthio)-2-methylpropanoate,a Key Intermediate in the Synthesis of Ureido Thioisobutyric Acid

A convenient and cost-effective synthesis of pharmacologically important tert-butyl-2-(4-2-aminoethyl)phenylthio)-2-methylpropanoate from commercially available 2-2-phenyl-1-ethanol is described.     

One-pot allyl-/crotylboration-Prins cyclization of aldehydes

Multi-substituted tetrahydropyrans (THPs) have been prepared via a one-pot, In(OTf)₃-catalyzed, sequential allyl-/crotylboration-Prins cyclization. The homoallylic borate intermediate formed during the allyl- and crotylboration was converted in situ to an oxocarbenium ion and trapped with a nucleophile. The reaction has been extended to include a one-pot allylboration-cross Prins cyclization as well.     

Rediscovering the Therapeutic Potential of Agarwood in the Management of Chronic Inflammatory Diseases

The inflammatory response is a central aspect of the human immune system that acts as a defense mechanism to protect the body against infections and injuries. A dysregulated inflammatory response is a major health concern, as it can disrupt homeostasis and lead to a plethora of chronic inflammatory conditions. These chronic inflammatory diseases are one of the major causes of morbidity and mortality worldwide and the need for them to be managed in the long term has become a crucial task to alleviate symptoms and improve patients’ overall quality of life. Although various synthetic anti-inflammatory agents have been developed to date, these medications are associated with several adverse effects that have led to poor therapeutic outcomes. The hunt for novel alternatives to modulate underlying chronic inflammatory processes has unveiled nature to be a plentiful source. One such example is agarwood, which is a valuable resinous wood from the trees of Aquilaria spp. Agarwood has been widely utilized for medicinal purposes since ancient times due to its ability to relieve pain, asthmatic symptoms, and arrest vomiting. In terms of inflammation, the major constituent of agarwood, agarwood oil, has been shown to possess multiple bioactive compounds that can regulate molecular mechanisms of chronic inflammation, thereby producing a multitude of pharmacological functions for treating various inflammatory disorders. As such, agarwood oil presents great potential to be developed as a novel anti-inflammatory therapeutic to overcome the drawbacks of existing therapies and improve treatment outcomes. In this review, we have summarized the current literature on agarwood and its bioactive components and have highlighted the potential roles of agarwood oil in treating various chronic inflammatory diseases.     

Synthesis and characterization of new O,O‐diethyl phosphorothioates derived from substituted tetrazolo[1,5‐a]quinolin‐ 4‐ylmethanol derivatives

A simple and convenient method is developed for the synthesis of new O,O‐diethyl O‐(substituted tetrazolo[1,5‐a]quinolin‐4‐yl)methyl phosphorothioates, which has been synthesized for the first time from tetrazolo[1,5‐a] quinolines via tetrazolo[1,5‐a]quinolin‐4‐ylmethanol derivatives. The structures of the all newly synthesized compounds were elucidated by analytical and spectral methods. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 20:436–441, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20570