Ethanol production by Bacillus stearothermophilus.

Imperial Users onl

A Novel User Pairing Scheme for Functional Decode-and-Forward Multi-way Relay Network

In this paper, we consider a functional decode and forward (FDF) multi-way relay network (MWRN) where a common user facilitates each user in the network to obtain messages from all other users. We propose a novel user pairing scheme, which is based on the principle of selecting a common user with the best average channel gain. This allows the user with the best channel conditions to contribute to the overall system performance. Assuming lattice code based transmissions, we derive upper bounds on the average common rate and the average sum rate with the proposed pairing scheme. Considering M-ary quadrature amplitude modulation with square constellation as a special case of lattice code transmission, we derive asymptotic average symbol error rate (SER) of the MWRN. We show that in terms of the achievable rates, the proposed pairing scheme outperforms the existing pairing schemes under a wide range of channel scenarios. The proposed pairing scheme also has lower average SER compared to existing schemes. We show that overall, the MWRN performance with the proposed pairing scheme is more robust, compared to existing pairing schemes, especially under worst case channel conditions when majority of users have poor average channel gains.Comment: 30 pages, 6 figures, submitted for journal publicatio

Electronic Properties of Disordered System

In this thesis we have calculated the density of state for an ordered and disordered model system using the Green’s function technique and the recursion method. We have considered a model of binary disordered system. The recursion parameters are calculated by transforming the Hamiltonian into a tridiagonal Hamiltonian. The infinite continued fraction size is truncated after 8th step

Antibiotic Resistance in Northern Mississippi Wetlands

Bacterial resistance to antibacterial agents is a condition in which there is no susceptibility or decreased susceptibility to antibacterial agents that ordinarily cause cell death or inhibition of bacteria. Bacterial resistance to antibacterial agents is a quantitative measurement of the efficiency or concentration expressed in micrograms per milliliter or as inhibition zones in millimeters for the diffusion technique of an antibacterial agent against a specific bacterium. In vitro methods for measurement of antibacterial activity are available that are based on testing increased concentrationsof antibacterial agent against a bacterial isolate to identify at which concentration the growth of the bacterium is inhibited. The lowest concentration at which detectable growth is inhibited is known as the minimum inhibitory concentration (MIC) of the antibacterial agent. Indeed the MIC indicates the relative measurement of the smallest concentration of antibacterial agent required to inhibit the growth (cell division) of a bacterium. Bacterial isolates from clinical environment are regularly tested for antibiotics susceptibility. Clinical isolates are selected for antibiotic susceptibility testing to monitor antibiotic resistance and multidrug-resistance so as to enhance medical therapy. However, with the increasing use of antibiotics outside the clinical area, it has become necessary to determine the antibiotics susceptibility of environmental bacterial isolates. It has become important to determine the spread of resistant organisms throughout the environment. Environmental isolates obtained from northern Mississippi wetlands were tested for antibiotic susceptibility to different class of antibiotics including novel antibiotics. Antibiotics susceptibility testing of the environmental isolates classified as being pathogenic were done using microdilution protocol specified by the National Committee on Clinical Laboratory Standards (NCCLS). The degree of growth response of each isolate in response to a particular antibiotic was recorded. Antibiotic potency for a particular isolate was determined in terms of the IC50 concentration (antibiotic concentration that affords only 50% growth of the bacteria), the minimum inhibitory concentration (lowest concentration of the antibiotic at which growth of bacteria is limited) and the minimum bactericidal concentration (the minimum concentration of the antibiotic at which growth of the organism is completely inhibited). MIC values of the antibiotics in the presence of each environmental isolate were compared to the MIC interpretative standards ((/xg/ml) for Enterobacteriacae according to NCCLS. Data from different antibiotics susceptibility testing suggested that the environmental isolates were resistant to the earlier generation of p-lactam class of antibiotics. On the contrary. resistance to tetracycline, a commonly used antibiotic in agriculture, was found to be intermediate. The environmental isolates were generally susceptible to newer generation of P-lactams, such as cefoxitin and ceftazidime. Antibiotic resistance to p-lactams is mainly attributed to the production of p-lactamase enzyme by bacteria that hydrolyzes the p-lactam ring of the P-lactams and reduces the effect of p-lactams. The newer generations of p-lactams possess a bulkier structure around the p-lactam ring to resist the action of p-lactamase enzyme. The results of this study suggest that environmental Plactamase enzyme did not evolve to recognize a bulkier structure of the new generations of P-lactams antibiotics

Low voltage, low power, bulk-driven amplifier

The importance of low voltage and low powered electronics is increasing with advances in medical electronics. This branch of electronics specifically requires low voltage and low power to make efficient innovative medical equipment. Low power electronics are also desirable because it conserves energy and power. This paper proposes a design of a differential in - differential our amplifier that uses a bulk-driven differential pair for the input pair. In addition, it also used bulk-driven current mirrors for the tail current sink and the active loads. The bulkdriven technique helps to achieve the low voltage design. 90nm CMOS technology was considered for the design but at the end SIGE 5AM process was chosen as it has low threshold voltage values maintaining good current - voltage characteristics. The software Cadence was used to simulate the design. A layout of the amplifier is out of the scope of this paper. A gain of 14 dB was achieved using a rail-to-rail voltage of 1V (0.5V to -0.5). The power dissipation was 102uW using 5pF capacitive loads. The values of the calculations match the values of the simulations quite well. Some of the differences can be explained by the lack of accurate knowledge of the some of the process parameters for the SIGE 5AM process. Overall, the design achieved its goals and a successful low voltage and low power fully differential amplifier was created with respectable gain. This amplifier can be used as an input stage for an operational amplifier

Social Constructivism: Teaching Counselors from a Multicultural Lens

The presentation explores the use of the social constructivist approach and pedagogy to teaching multicultural competency and utilizing the social justice advocacy model. The teaching strategies utilized in this approach can enhance student learning experiences and help in meeting the student learning outcomes. With this approach the educators can help students practice components of self-awareness, knowledge, and skills

CementalTear Predisposing Factors, Clinical Signs Symptoms, Diagnosis and its Management

A cemental tear is a rare condition in which a total or partial detachment of the cementum occurs along the root surfaceat the cemento-dentinal junction and is associated with moderate to severe periodontal attachment loss. Literature regarding this article was searched fromPub Med, Medline and Google during the period of Jan 2008- Dec 2012.Cemento-dentinal tear is more frequently seen in older men above 60 years, single-rooted vital or nonvital teeth, particularly the incisors and premolars areinvolved. Other significant etiological factors are traumatic occlusion, poor ability of tissue healing due to age and structural weakness of the cementum. Its diagnosis can be confirmed by clinical signs and symptoms,(presence of localized periodontal pockets with exudates and localized pain) by radiographic findings(as a radiopaque fragment) and surgical inspection. The treatment of cemental tears involves scaling and root planning, open flap debridement, bone graft, regenerative tissue guide, apical surgery and dental extractio