Design of the next generation (4G) systems is one of the most active and important area of research and development in wireless communications. The 2G and 3G technologies will still co-exist with the 4G for a certain period of time. Other applications such as wireless LAN (Local Area Network) and RFID are also widely used. As a result, there emerges a trend towards integrating multiple wireless functionalities into a single mobile device. Low noise amplifier (LNA), the most critical component of the receiver front-end, determines the sensitivity and noise figure of the receiver and is indispensable for the complete system. To satisfy the need for higher performance and diversity of wireless communication systems, three LNAs with different structures and techniques are proposed in the thesis based on the 4G applications. The first LNA is designed and optimized specifically for LTE applications, which could be easily added to the existing system to support different standards. In this cascode LNA, the nonlinearity coming from the common source (CS) and common gate (CG) stages are analyzed in detail, and a novel linear structure is proposed to enhance the linearity in a relatively wide bandwidth. The LNA has a bandwidth of 900MHz with the linearity of greater than 7.5dBm at the central frequency of 1.2GHz. Testing results show that the proposed structure effectively increases and maintains linearity of the LNA in a wide bandwidth. However, a broadband LNA that covers multiple frequency ranges appears more attractive due to system simplicity and low cost. The second design, a wideband LNA, is proposed to cover multiple wireless standards, such as LTE, RFID, GSM, and CDMA. A novel input-matching network is proposed to relax the tradeoff among noise figure and bandwidth. A high gain (>10dB) in a wide frequency range (1-3GHz) and a minimum NF of 2.5dB are achieved. The LNA consumes only 7mW on a 1.2V supply. The first and second LNAs are designed mainly for the LTE standard because it is the most widely used standard in the 4G communication systems. However, WiMAX, another 4G standard, is also being widely used in many applications. The third design targets on covering both the LTE and the WiMAX. An improved noise cancelling technique with gain enhancing structure is proposed in this design and the bandwidth is enlarged to 8GHz. In this frequency range, a maximum power gain of 14.5dB and a NF of 2.6-4.3dB are achieved. The core area of this LNA is 0.46x0.67mm2 and it consumes 17mW from a 1.2V supply. The three designs in the thesis work are proposed for the multi-standard applications based on the realization of the 4G technologies. The performance tradeoff among noise, linearity, and broadband impedance matching are explored and three new techniques are proposed for the tradeoff relaxation. The measurement results indicate the techniques effectively extend the bandwidth and suppress the increase of the NF and nonlinearity at high frequencies. The three proposed structures can be easily applied to the wideband and multi-standard LNA design.

No description available.

After two outbreaks of salmonellosis that were linked to the consumption of almonds in 2001 and 2004, scientific community and industry have encouraged the study of pathogen inactivation kinetics in almonds. However, these studies often have overlooked the increase of water resulting from the inoculation of almonds. This increase of free water may result in data that may be overestimating the final outcome of treatments applied to pasteurize almonds in industrial settings. Therefore, in 2011 a study of almonds was performed at Texas A&M University to determine whether there was a need for Aw restoration. In this study, the effect of accelerated drying on the reduction of Salmonella on almonds was investigated, Salmonella Entritidis PT 30 isolated from one of the outbreaks linked to almonds, and Salmonella Typhimurium LT2 were used. For irradiation, the effect of vacuum packaging and air packaging on the sensitivity of Salmonella to e- beam irradiation was evaluated for both accelerated drying and conventional drying. The D value for Salmonella Entritidis PT 30 when treated with blanching at 88°C with accelerated drying was 10.7± 0.1 s, and 12.8 ± 0.3 s with conventional drying. When subjected to oil roasting at 127˚C, the D values were 10.5 ± 0.1 s with accelerated drying, and 10.2 ± 0.2 s with conventional drying. For irradiation treatments, the D10 value for vacuum packaged almonds was 0.35 ± 0.02 kGy with accelerated drying, and 0.38 ± 0.04 kGy with conventional drying. When irradiated in the presence of air, the D10 value of Salmonella was 0.26±0.04 kGy for almonds with accelerated drying, and 0.29 ± 0.03 kGy conventional drying. In conclusion, the accelerated drying process resulted in greater reduction in Salmonella on almonds in comparison to conventional drying when subjected to blanching but no differences were found for oil roasting (P > 0.05). For e-beam irradiation the D_10 values were significantly greater (P < 0.05) for vacuum with accelerated drying than for Air almonds with accelerated drying. This indicates that if a process applied in the industry were to be developed based on challenge studies when conventional drying was achieved, the almonds might likely be subjected to a treatment that is stronger than necessary to achieve pasteurization.

No description available.

No description available.

No description available.

No description available.

I investigated the effects of continuous administration of fluoxetine, a serotonin reuptake inhibitor, on energy expenditure, body temperature, and thyroid and catecholamine metabolism during weight reduction using a very low calorie diet (VLCD, Optifast, 1757 kJ/day) followed by a balanced deficit diet (BDD, 5016 kJ/day). Fluoxetine (60 mg/day by mouth, n = 10) or placebo (n = 10) were administered during 3 weeks of inpatient VLCD followed by 8 weeks of outpatient BDD in a double-blind, randomized design. A similar amount of weight was lost in both groups during the VLCD, but by the end of the BDD total weight loss in the fluoxetine group was significantly greater (11.0 $ pm$ 1.1 kg vs. 7.0 $ pm$ 1.0 kg, mean $ pm$ SEM, p $<$ 0.015). Resting metabolic rate (RMR) increased by 4.4 $ pm$ 1.8% (p $<$ 0.01) in the fluoxetine group but did not change in the placebo group during the first week of the VLCD, but subsequently decreased significantly in both groups as dieting continued. However, RMR remained consistently higher in the fluoxetine group for the duration of the VLCD period. No further change in RMR occurred in either group during the BDD period. The thermic effect of food did not change after VLC dieting plus fluoxetine or placebo treatment. Body temperature increased within 2 days of fluoxetine treatment by a mean of 0.3$ sp circ$C, p $<$ 0.025 and remained elevated throughout the VLCD but was unchanged in the placebo group. VLCD therapy reduced serum levels of T$ sb3$, free T$ sb3$ Index and 24-hour urinary excretion of dopamine, norepinephrine, metanephrine and normetanephrine equivalently in both groups. A thermogenic effect of fluoxetine is demonstrated in humans for the first time. The anorectic effect of fluoxetine may be related to its temperature elevating effect.

Dissertation submitted in partial compliance with the requirements for the Masters Degree in Technology: Chiropractic, Durban University of Technology, 2010. / Background: Low back pain (LBP) is the most prevalent musculoskeletal condition experienced by human beings and the most common cause of disability in developed nations. Psychosocial factors, involving aspects of social and psychological behaviour, have previously been documented as potential risk factors in the development of adult LBP. However, more research is required to fully understand the role of psychosocial risk factors on the prevalence of LBP amongst adolescents. Objective: To determine the prevalence of LBP and to identify selected psychosocial risk factors associated with LBP amongst Grade 12 learners in the Greater Durban area. Methods: A population-based study was conducted amongst a stratified random sample of 20 public secondary schools in all three educational districts in the Greater Durban area. Data was collected by means of a structured questionnaire administered to the sample population consisting of Grade 12 learners. Using an exploratory research design, the individuals reported on demographics as well as prevalence, severity, frequency and chronicity of LBP. In addition, data was obtained regarding various psychosocial risk factors including depression, exam stress and anxiety, socio-economic status, family history of LBP, smoking, alcohol and drug abuse amongst the respondents. Results: The prevalence of LBP was 57.42% with a median frequency of 8 times a month. About a third (33.9%) of the respondents experienced difficulty bending whilst 35% reported that their LBP spread down to the legs below their knees. The daily activity most affected by LBP was having a good night‟s sleep (50.6%), followed closely by playing sports (47.4%) and concentrating in class (46.6%). The majority of the respondents that suffered from LBP had taken pain relief medication (47.1%) whilst only 21% of the respondents had missed school because of LBP. With regards to the psychosocial risk factors under investigation, three of the risk factors did not show any association to LBP. They included socio-economic status, smoking and recreational drug use. In contrast, five psychosocial risk factors showed an 6 association to LBP. They included alcohol abuse, family history, exam stress, anxiety and depression. Finally, after adjusting for all other risk factors for adolescent LBP, depression and high exam stress showed the strongest correlation with the occurrence of LBP amongst Grade 12 learners in the Greater Durban area. Conclusion: LBP amongst adolescents is a common problem that increases with age, representing a risk for LBP in adulthood. The researcher is of the opinion, that this illustrates the need for further investigations with more profound studies on the risk factors so that more light can be shed on how to manage this ever-growing problem.

No description available.