An energy efficient void avoidance opportunistic routing protocol for underwater sensor

Underwater sensor network is an emerging technology due to its numerous applications in aqueous environments. However, limitations of these networks include limited bandwidth, high propagation delays and power constraints. Hence, new routing protocols must be designed specifically for USN. Opportunistic routing offers a promising method to overcome these limitations. The proposed protocol is a novel energy-efficient void avoidance opportunistic routing algorithm. The protocol deals with the issue of void holes during transmission while reducing energy consumption and keeping the packet delivery ratio at a satisfactory level. To evaluate the performance, two common metrics have been used for routing protocols in USNs; energy consumption and packet delivery ratio. Simulations were carried out in ns2 with Aqua-Sim. The performance of the proposed routing protocol is compared to VAPR. The performance evaluation of EEVA-OR indicate its benefit as compared to VAPR in terms of void detection, energy consumption and packet delivery ratio

The effect of alcohol on the performance of lipase-immobilized enzymatic membrane reactor for esterification of (R,S)-ketoprofen

The effect of alcohols on the performance of lipase-immobilized enzymatic membrane reactor (EMR) for enantioselective esterification of (R,S)-ketoprofen has been studied. In this work, mixed solvent medium was used and the (R)-ketoprofen was reacted with the different alcohols in the presence of immobilized lipase B from Candida antartica, leaving the target product (S)-ketoprofen in its unreacted form. The alcohols involved in the reactions were ethanol, butanol, heptanol and 2-ethoxyethanol. The chain length of alcohol was found to significantly affect the performance of the esterification in EMR. Through the alcohols screening, the esterification reaction using ethanol in EMR showed higher initial rate, conversion, enzyme enantioselectivity, enantiomeric excess of substrate (ees) and enantiomeric excess of product (eep). However the results with butanol showed less inhibition effect on a wider range of temperatur

Prevalence and management of menopausal symptoms in malaysian women during peri and post menopause

Women upon reaching menopause often silently suffer debilitating physical and psychological symptoms. The peri and postmenopausal period constitutes a challenging transition time for women’s health, and good menopausal health is a crucial aspect in healthy and successful aging. These situations affects women globally however Malaysian women are mostly unaware how to manage onset of menopause. This study aims to systematically review published data for the prevalence and management of menopausal symptoms in Malaysian women. Findings indicated that Malaysia women experienced similar menopausal symptoms as other women globally. However, these studies indicated that Malaysian women lack the knowledge to manage and prepare for menopause. The menopausal transition demarks dramatic changes at the hormonal, physiological, and metabolic level. Eventually, our study will develop an online tool to provide information and manage menopausal symptom

Study Of Rice Husk Ash (RHA)-Based Sorbents For Simultaneous Removal Of Sulfur Dioxide (S02) And Nitrogen Oxides (Nox) From Flue Gas.

Adsorbents for dry-type flue gas desulfurization (FGD) were prepared from rice husk ash (RHA), calcium oxide and NaOH as additive by water hydration method. Two types of RHA were used in the experiment, one was obtained directly from the mill (black colored), and the other was obtained after pre-treatment of the black colored RHA with temperature at 600°C

Bioconversion Of Synthesis Gas To Ethanol In A CSTR.

The depletion sources of fossil fuels and chemical feedstock, also the oil crisis in 70’s had drawn the world to find alternative clean renewable resources. The production of fuel by microbial culture was considered as an alternative source

Effect of Reaction Parameters on the Lipase-Catalyzed Kinetic Resolution of (RS)-Metoprolol

Racemic metoprolol is a selective ß1-blocker, which is used in cardiovascular disease treatment. It has been found that (S)-metoprolol has a higher affinity to bind the ß-adrenergic receptor compared to (R)-metoprolol. Moreover, the regulatory authorities’ high market demand and guidelines have increased the preference for single enantiomer drugs. In this work, the lipase-catalyzed kinetic resolution of racemic metoprolol was performed to obtain the desired enantiomer. The type of lipase, acyl donor, and solvent were screened out. This was achieved by Candida antarctica B lipasecatalyzed transesterification of racemic metoprolol in hexane and vinyl acetate as the solvent and an acyl donor, which gave maximum conversion of (S)-metoprolol (XS) of 52%, enantiomeric excess of substrate, (ees) of 92% and product (eeP) of 90% with enantiomeric ratio (E) of 62. This method can be considered as green chemistry, which can be applied to produce other enantiopure beta-blockers

Hydrogen as clean fuel via continuous fermentation by anaerobic photosynthetic bacteria, Rhodospirillum rubrum

Hydrogen has been considered a potential fuel for the future since it is carbon-free and oxidized to water as a combustion product. Bioconversion of synthesis gas to hydrogen was demonstrated in a continuous fermentation utilizing malate as a carbon source. Rhodospirillum rubrum, an anaerobic photosynthetic bacterium catalyzed water gas shift reaction which was used in this research. The synthesis gas (CO) was used as a source of energy along with tungsten light supplied for growth and bioconversion of the photosynthetic bacteria. The microbial process in fermentation media was carried out in continuous culture to observe the effect of light intensity, agitation and liquid dilution rate on hydrogen production. The maximum hydrogen yield at 500 rpm was 0.65 mmol H2/mmol CO. Desired media flow rate was preferable for high hydrogen production. At 0.65 ml/min media, hydrogen was produced at 7.2 mmol/h. This new approach, use of biocatalyst, can be considered as an alternative method to the conventional Fischer Tropsch synthetic reactions, which were able to convert synthesis gas into hydrogen. Key Words: Hydrogen, syngas, continuous bioreactor, Rhodospirillum rubrum, light intensity, agitation rate and flow rate. African Journal of Biotechnology Vol.3(10) 2004: 503-50

5-Chloro-8-hydr­oxy-6-methyl-1,4-naphthoquinone

The mol­ecule of the title compound, C11H7ClO3, is planar, with a maximum deviation of 0.0383 (10) Å from the naphthoquinone plane. An intra­molecular O—H⋯O hydrogen bond generates an S(6) ring motif. The crystal packing is stabilized by inter­molecular C—H⋯O hydrogen bonds. Short intra­molecular Cl⋯O [2.8234 (8) Å] and O⋯O [2.5530 (11) Å], and inter­molecular Cl⋯Cl [3.2777 (3) Å] contacts further stabilize the crystal structure

Synthesis of Enzyme-based Organic-Inorganic Hybrid Nanoflower Particles

Enzyme-incorporated hybrid nanostructures are the immobilization of enzymes and inorganic components that exhibits promising characteristics in various industries. The immobilization of enzymes onto nanomaterial is naturally based to accommodate the enzymatic activity, stability, recyclability as well as their catalytic functions. The designing of these conjugates can improve the overall enzymatic performance by imparting their novel properties onto the system in comparison to conventional free enzymes which experience drawbacks in terms of deactivation or denaturing. A facile and ultrafast method is described in this paper to synthesize a novel enzyme-incorporated lipase/Cu3(PO4)2 hybrid nanoflower (NF). The physical properties of the hybrid NF allow easier retrieval which indicates its higher reusability and recyclability value. The enzyme loading capacity was found to be 95.1% whereas, the catalytic performance of lipase/Cu3(PO4)2 hybrid NF at the optimal conditions resulted in a specific enzyme activity of 1752 U/g corresponding to an increment of 90.5% to that of free lipase. This indicates that the well-designed lipase/Cu3(PO4)2 hybrid NF to be highly efficient in industrial biocatalytic applications. Meanwhile, in future work, we aim to study its operational stability and reusability to enzymatically degrade biopolymers through hydrolysis process

5-Hydr­oxy-8-nitro-1,4-naphthoquinone

The title compound, C10H5NO5, features an intra­molecular O—H⋯O hydrogen bond, forming a six-membered ring with an S(6) ring motif. The nitro group makes a dihedral angle of 71.66 (5)° with the plane of the benzene ring to which it is bound. The two rings are almost coplanar, with a dihedral angle of 4.44 (5)°. Short inter­molecular distances between the centroids of the six-membered rings [3.7188 (6)–3.8299 (6) Å] indicate the existence of π–π inter­actions. The inter­esting features of the crystal structure are the short inter­molecular O⋯O and O⋯N inter­actions. The crystal packing is stabilized by intra­molecular O—H⋯O and inter­molecular C—H⋯O (×3) hydrogen bonds, and C—H⋯π inter­actions