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The use of physical plasma to treat cancer is an emerging field, and interest in its applications in oncology is increasing rapidly. Physical plasma can be used directly by aiming the plasma jet onto cells or tissue, or indirectly, where a plasma-treated solution is applied. A key scientific question is the mechanism by which physical plasma achieves selective killing of cancer over normal cells. Many studies have focused on specific pathways and mechanisms, such as apoptosis and oxidative stress, and the role of redox biology. However, over the past two decades, there has been a rise in omics, the systematic analysis of entire collections of molecules in a biological entity, enabling the discovery of the so-called “unknown unknowns.” For example, transcriptomics, epigenomics, proteomics, and metabolomics have helped to uncover molecular mechanisms behind the action of physical plasma, revealing critical pathways beyond those traditionally associated with cancer treatments. This review showcases a selection of omics and then summarizes the insights gained from these studies toward understanding the biological pathways and molecular mechanisms implicated in physical plasma treatment. Omics studies have revealed how reactive species generated by plasma treatment preferentially affect several critical cellular pathways in cancer cells, resulting in epigenetic, transcriptional, and post-translational changes that promote cell death. Finally, this review considers the outlook for omics in uncovering both synergies and antagonisms with other common cancer therapies, as well as in overcoming challenges in the clinical translation of physical plasma.

Memory B cells (MBCs) and plasma antibodies against

Malaria, caused by parasites of the Plasmodium genus, is responsible for significant morbidity and mortality globally. Chronic Plasmodium falciparum exposure affects the B cell compartment, leading to the accumulation of atypical memory B cells (atMBCs). IgM-positive (IgM+) and IgG+ atMBCs have not been compared in-depth in the context of malaria, nor is it known if atMBCs in malaria-experienced individuals are different from phenotypically similar B cells in individuals with no known history of Plasmodium exposure. To address these questions, we characterized the B cell receptor (BCR) repertoire of naive B cells (NBCs), IgM+ and IgG+ classical MBCs (cMBCs), and IgM+ and IgG+ atMBCs from 13 malaria-naive American adults and 7 malaria-experienced Ugandan adults. Our results demonstrate that P. falciparum exposure mainly drives changes in atMBCs. In comparison to malaria-naive adults, the BCR repertoire of Plasmodium-exposed adults showed increased levels of somatic hypermutation in the heavy chain V region in IgM+ and IgG+ atMBCs, shorter heavy chain complementarity-determining region 3 (HCDR3) in IgG+ atMBCs, and increased usage of IGHV3-73 in IgG+ cMBCs and both IgM+ and IgG+ atMBCs. Irrespective of Plasmodium exposure, IgM+ atMBCs closely resembled NBCs, while IgG+ atMBCs resembled IgG+ cMBCs. Physicochemical properties of the HCDR3 seemed to be intrinsic to cell type and independent of malaria experience. The resemblance between atMBCs from Plasmodium-exposed and naive adults suggests similar differentiation pathways regardless of chronic antigen exposure. Moreover, these data demonstrate that IgM+ and IgG+ atMBCs are distinct populations that should be considered separately in future analyses. IMPORTANCE Malaria, caused by Plasmodium parasites, still contributes to a high global burden of disease, mainly in children under 5 years of age. Chronic and recurrent Plasmodium infections affect the development of B cell memory against the parasite and promote the accumulation of atypical memory B cells (atMBCs), which have an unclear function in the immune response. Understanding where these cells originate from and whether they are beneficial in the immune response to Plasmodium will help inform vaccination development efforts. We found differences in B cell receptor (BCR) properties of atMBCs between malaria-naive and malaria-experienced adults that are suggestive of divergent selection processes, resulting in more somatic hypermutation and differential immunoglobulin heavy chain V (IGHV) gene usage. Despite these differences, atMBCs from malaria-naive and malaria-experienced adults also showed many similarities in BCR characteristics, such as physicochemical properties of the HCDR3 region, suggesting that atMBCs undergo similar differentiation pathways in response to different pathogens. Our study provides new insights into the effects of malaria experience on the B cell compartment and the relationships between atMBCs and other B cell populations.

SARS-CoV-2 infection elicits a robust B cell response, resulting in the generation of long-lived plasma cells and memory B cells. Here, we aimed to determine the effect of COVID-19 severity on the memory B cell response and characterize changes in the memory B cell compartment between recovery and five months post-symptom onset. Using high-parameter spectral flow cytometry, we analyzed the phenotype of memory B cells with reactivity against the SARS-CoV-2 spike protein or the spike receptor binding domain (RBD) in recovered individuals who had been hospitalized with non-severe (n = 8) or severe (n = 5) COVID-19. One month after symptom onset, a substantial proportion of spike-specific IgG+ B cells showed an activated phenotype. In individuals who experienced non-severe disease, spike-specific IgG+ B cells showed increased expression of markers associated with durable B cell memory, including T-bet and FcRL5, as compared to individuals who experienced severe disease. While the frequency of T-bet+ spike-specific IgG+ B cells differed between the two groups, these cells predominantly showed an activated switched memory B cell phenotype in both groups. Five months post-symptom onset, the majority of spike-specific memory B cells had a resting phenotype and the percentage of spike-specific T-bet+ IgG+ memory B cells decreased to baseline levels. Collectively, our results highlight subtle differences in the B cells response after non-severe and severe COVID-19 and suggest that the memory B cell response elicited during non-severe COVID-19 may be of higher quality than the response after severe disease.

Malaria remains a significant contributor to the global burden of disease, with around 40% of the world’s population at risk of Plasmodium infections. The development of an effective vaccine against the malaria parasite would mark a breakthrough in the fight to eradicate the disease. Over time, natural infection elicits a robust immune response against the blood stage of the parasite, providing protection against malaria. In recent years, we have gained valuable insight into the mechanisms by which IgG acts to prevent pathology and inhibit parasite replication, as well as the potential role of immunoglobulin M (IgM) in these processes. Here, we discuss recent advances in our understanding of the mechanisms, acquisition, and maintenance of naturally acquired immunity, and the relevance of these discoveries for the development of a potential vaccine against the blood stage of Plasmodium falciparum.

This study aims developing customized novel data acquisition for photovoltaic systems under extreme climates by utilizing off-the-shelf components and enhanced with data analytics for performance evaluation and prediction. Microcontrollers and sensors are used to measure meteorological and electrical parameters. Customized signal conditioning, which can withstand high-temperature along with microcontrollers’ development boards enhanced with appropriate interfacing shields and wireless data transmission to iCloud IoT platforms, is developed. In addition, an automatically controllable in-house electronic load of the PV system was developed to measure the maximum power possible from the system. LabVIEW™ program was used to allow ubiquitous access and processing of the recorded data over the used IoT. Furthermore, machine learning algorithms are utilized to predict the PV output power by utilizing data collected over a two-year span. The result of this study is the commissioning of original hardware for PV study under extreme climates. This study also shows how the use of specific ML algorithms such as Artificial Neural Network (ANN) can successfully provide accurate predictions with low root-mean-squared error (RMSE) between the predicted and actual power. The results support reliable integration of PV systems into smart-grids for efficient energy planning and management, especially for arid and semi-arid regions.

Study Objective The objective of this study is to report our center's series of robotic-assisted laparoscopic abdominal cerclage (RALAC) placement during pregnancy. Design Descriptive study (Canadian Task Force classification III). Setting Single academic institution. Patients Patients undergoing RALAC placement during pregnancy. Interventions Eleven patients underwent RALAC. Measurements and Main Results Nine out of 11 (81.8%) primary RALAC procedures resulted in a viable live-born neonate; 8 (72.7%) were born at >34 weeks of gestation. Three patients (27.3%) had preterm premature rupture of membranes on postoperative day one, 2 of whom subsequently underwent a dilation and curettage, and 1 patient carried the pregnancy to 29 weeks and delivered a live-born neonate. Four patients had subsequent pregnancies after placement of a RALAC in the antepartum period, all of whom carried successfully beyond 36 weeks, for a total of 16 pregnancies. Fourteen pregnancies (87.5%) resulted in a live birth, and 13 pregnancies (81.3%) were delivered beyond 34 weeks. Conclusion RALAC is a minimally invasive procedure with an acceptable risk profile and comparable efficacy to traditional open abdominal cerclage. RALAC may be considered an acceptable alternative to open abdominal cerclage in pregnancy, and may be a particularly favorable option in certain settings.

“Solar photovoltaic (PV) energy in GCC”- the term seems convincing to many solar PV industries due to high solar exposure in GCC region. However, long-term effects such as dust accumulation and seasonal variation are major drawbacks for solar PV energy. This research aims to investigate PV performance for two years in the harsh environment of Qatar. For data collection, a wireless system has been developed to record critical parameters such as solar irradiance, relative humidity, ambient temperature, PV module temperature, dust, wind speed, and output PV power. Results show that due to panel dusting for eight months, the PV output power decreased by 50%. Also, owing to lower ambient temperatures, clearer sky and cleaner panels due to occasional rainfall, the PV panels show higher output power in Winter than in Summer season. Besides, within one-month, a cloudy condition in Winter causes 20% drop in average output power. Therefore, a strategic plan is needed to build and manage efficiently a PV solar plant in harsh environments such as of Qatar. Energy management requires prediction of energy yield. To this end, using machine-learning, a mathematical model has been established which can predict the output power from PV panels under different environmental conditions.

Soiling losses of photovoltaic (PV) panels due to dust lead to a significant decrease in solar energy yield and result in economic losses, this hence poses critical challenges to the viability of PV in smart grid systems. In this paper, these losses are quantified under Qatar’s harsh environment. This quantification is based on experimental data from long-term measurements of various climatic parameters and the output power of PV panels located in Qatar University’s Solar facility in Doha, Qatar, using a customized measurement and monitoring setup. A data processing algorithm was deliberately developed and applied, which aimed to correlate output power to ambient dust density in the vicinity of PV panels. It was found that, without cleaning, soiling reduced the output power by 43% after six months of exposure to an average ambient dust density of 0.7 mg/m3. The power and economic loss that would result from this power reduction for Qatar’s ongoing solar PV projects has also been estimated. For example, for the Al-Kharasaah project power plant, similar soiling loss would result in about a 10% power decrease after six months for typical ranges of dust density in Qatar’s environment, this, in turn, would result in an 11,000 QAR/h financial loss. This would pose a pressing need to mitigate soiling effects in PV power plants.

A key factor in future eco-friendly and reliable energy systems for network stability is energy prediction of renewable resources. However, the climate-induced performance degradation represents a major drawback to solar making them unreliable for unattended or remote plants. We propose a customized cost-effective solution that allows monitoring and predicting the performance of PV systems, fostering thus efficient planning and control strategies for network stability. More specifically, we design an in-house system featuring a buck-boost converter enhanced with a maximum power point tracker (MPPT) serving as a PV load, sensors' system that collects climatic parameters including dust, wireless Radio, and a LabVIEW based monitoring and recording station. We have presented thoroughly all the system design steps. The system was deployed in Doha over a long period of time under harsh environment. It allows accessing and processing of recorded data ubiquitously over the web or from a database. Based on the recorded data, the power output for a given PV technology under any environment can be analyzed. Results predict that the maximum power output from a Poly-crystalline panel decreases by around 30% for a dust exposure of five months. This would suggest cleaning needs and advise on cleaning frequencies of PV panels. The authors would like to thank Qatar University for funding this research ( QUUG-CENG-DEE-12/13-2 ) and providing the necessary tools and equipment. Also, we would like to thank Dr. Ahmed Mohammed Massoud (EE Dept. of Qatar University) for his support. Scopus

Congenital high airway obstruction syndrome (CHAOS) encompasses a heterogeneous group of pathologies leading to poor lung development and difficulty oxygenating the newborn after delivery. While previously uniformly fatal, the ex utero intrapartum therapy (EXIT) procedure has provided a method to treat these patients and provide an airway to potentiate survival. We present a patient diagnosed prenatally with CHAOS secondary to tracheal atresia complicated by severe intra-uterine growth restriction (IUGR) who was successfully delivered via an EXIT procedure at 33-weeks. Multidisciplinary care and planning is paramount.

The present work reports on the effect of hydrogen on the mechanical behavior of API 5L X70 ageing. Bending test specimens underwent solution treatment in an electric induction furnace at 1100°C for 30 min under argon atmosphere and water quenching and then ageing process for five temperatures in the range between 204 to 650°C for 30 min of time exposition and water quenching, respectively. The microstructural characterization was examined by scanning electron microscopy (SEM) and matrix samples ageing showed microstructures, acicular ferritic, polygonal ferrite, bainitic-ferrite, degenerate perlite and retained austenite and energy dispersive spectroscopy (EDS) evidencing the presence of carbonitrures type Nb, Ti, V (N, C). Hydrogen was introduced in a sample of bending test, through cathodic charging, applying a current density of 50 mA/cm2. Three point bend test was carry out on specimen on API X70 with and without hydrogen and the result showed a reduction of ductility and 65% of index of embrittlement (IH). Also, samples undergoing ageing with hydrogen showed an increase in bending stress compared to a sample undergoing ageing without hydrogen, and the parameter (IH) decreased in the range of 21 to 29% due to the formation of traps. The fracture surface of bend tested samples were examined using a SEM.

The kinetics of Maillard reaction in lactose-hydrolysed skim milk powder and related systems containing carbohydrate mixtures were analysed. The effect of the increase of water activity and temperature during storage of the commercial product was also evaluated. In systems with two and three carbohydrates, a marked decrease of the reaction rate was observed when monosaccharides were partially replaced by lactose, notwithstanding the fact that the former still remained in a higher proportion than lysine. The rate of available lysine loss in lactose-hydrolysed milk was mostly affected by the presence of galactose. The reaction rate constants at aw 0.52 and at 37 and 50 °C were higher than at aw 0.33. However, no significant differences were observed at 60 °C. Temperature is the most important factor to be controlled in order to minimise nutritional deterioration during storage.

HIV-1 nonnucleoside reverse transcriptase inhibitors (NNRTIs) are part of the combination therapy currently used to treat HIV infection. The features of a new NNRTI drug for HIV treatment must include selective potent activity against both wild-type virus as well as against mutant virus that have been selected by use of current antiretroviral treatment regimens. Based on analogy with known HIV-1 NNRTI inhibitors and modeling studies utilizing the X-ray crystal structure of inhibitors bound in the HIV-1 RT, a series of substituted 2-quinolones was synthesized and evaluated as HIV-1 inhibitors.

This paper describes a phase-locked loop (PLL) converter with improved dynamic response for the determination of mechanical angle from sinusoidal encoders and resolvers. PLL converters are tracking-type converters that use the sine and cosine signals of the transducer in a closed-loop arrangement aiming to match an estimated output angle to the true angle encoded in the sine and cosine input signals. Such a scheme requires means to determine the sine and cosine of the estimated output angle; conventional converters achieve this by using voltage-controlled oscillators, digital-to-analog converter (DAC), counter, and lookup tables. The proposed converter simplifies implementation by making use of the estimated output angle signal to approximate its sine and cosine using analog triangle-sine conversion technique. A new method is also proposed to enhance the dynamic performance of the converter enabling near instantaneous response. This paper describes the proposed method, full details of its analog implementation, and experimental results. Results demonstrate agreement with theory and computer simulation. Scopus

This paper describes a novel and high-performance phase-locked loop (PLL) resolver converter for the measurement of mechanical angles. The proposed method does not require the use of demodulators, voltage-controlled oscillator, digital-to-analog converter, counter, and lookup tables, that are associated with conventional PLL converters. The proposed method employs full-wave rectifiers to obtain the absolute values of the modulated resolver signals. This scheme results in a triangular output voltage and two binary outputs that represent a measure of the input angle. The required sine and cosine of the estimated angle, which are needed for PLL converters, are determined using simple approximation techniques. The proposed method can be used to measure angles in the full 360° range, is simpler than the available techniques, and may be easily implemented using digital or basic analog electronic circuitry. This paper describes the proposed method, full details of its implementation using standard electronic components, and experimental results. The performance of the proposed converter is comparable with that of a commercial product. Scopus

Resolvers are used for both absolute angular and linear position sensing. A robust amplitude to phase converter is described for the determination of position from the sine and cosine output signals of the resolver. The scheme is based on a linearization technique for converting the co-sinusoids into a nearly perfect triangular signal from which the angle is determined using simple linear equation. Even though the amplitudes of the resolver output signals are proportional to that of the resolver excitation signal, the proposed amplitude to phase technique is robust to fluctuation and drift of the amplitude and frequency of the excitation signal. The theoretical absolute error of non-linearity of the converter is 0.0082 degree over the full 360 degree range. The converter may be implemented numerically or electronically. In this work, details are given for an implementation using basic analogue electronic circuitry The theory of operation and experimental results are given. Anglia Ruskin University;IEEE Industrial Electronics Society (IES) Scopus

To describe the corneal endothelial cell density and morphology in normal adult Filipino eyes.Specular microscopy was performed in 640 eyes of 320 normal Filipino volunteers aged 20 to 86 years. Of these, 163 were male, and 157 were female. Mean cell density (MCD), mean cell area (MCA), coefficient of variation (CV) in cell size (polymegathism), and hexagonality were recorded and analyzed in relation to fellow eyes, gender, and age.MCD was 2798 +/- 307.2 cells/mm, and MCA was 363.0 +/- 40.3 microm. Results showed that women had a MCD 7.8% greater than men (P0.01). Regression analysis showed a consistent decrease in MCD (r = -0.47) and increase in MCA (r = 0.45) from 20 to 60 years of age. This was followed by a marked decrease in correlation and apparent trend reversal for both variables in the groups above 60 years (MCD r = 0.18, MCA r = -0.04) accompanied by a marked increase in CV in cell size (20-60 years r = -0.04,60 years r = 0.33). A very low negative correlation (r = -0.10) was noted between hexagonality and increasing age through all age groups.The first normative data for the endothelium of Filipino eyes are reported. There are statistically significant differences in MCD between genders, and a consistent decrease in MCD and increase in MCA with age only until 60 years old, after which correlation between age and these variables decreases. Polymegathism and correlation between CV in cell size and age markedly increase after age 60.

The main objective of this work was to generate information about traits associated with adaptation of peach seedlings to subtropical climates, as a background for breeding and selection. Three plots were established along an altitudinal gradient (2700 to 1700 m) to study a wide range of germplasm including local and introduced genotypes as well as hybrids between them. Seedling vigor after the first and second growth cycles in the field was one of the most important indicators of seedling adaptation to local conditions. It was directly associated with the seedling capacity to enter rest. Several environmental variables may trigger ecodormancy, associated with a strong reduction of apical growth and defoliation, which may start in the middle of the summer in cultivars from higher latitudes, while locally adapted seedlings and cultivars had continuous growth from January to November. Selection strategies should be based on 'adaptive suitability' for both climate and horticultural traits associated with production efficiency and fruit quality.

This study investigated children's attitudes towards children with Down syndrome in Ireland, France, Portugal and Spain. A sample of 805 children divided approximately equally by country, sex. grade level (9 and 11 years of age), and school type (inclusive or non-inclusive) participated in the study. Differences are reported for each independent variable on three dependent variables. sociability. attitude to inclusion and use of negative words to describe a child with Down syndrome. For example, in the Iberian sample, younger children. girls and children not in inclusive classrooms were more sociable towards children with Down syndrome. Further, attitude towards inclusive practice was influenced by country, age and school type. Main effects were qualified by some interactions. Results were discussed in tenns of their implications for educating children to respect differences.

The causes of darkening in honey have been attributed to Maillard reaction, fructose caramelization and reactions of polyphenols, however, no systematic studies exist on this subject. The influence of composition and initial color on the rate of darkening of several Argentine honeys submitted to storage at 37°C during 90 days was evaluated through spectrocolorimetric measurements. The most suitable color functions to evaluate darkening of honeys [lightness (Lab*), browning index (BI), metric chroma (Cab*), metric hue (Hab*) and 1/Z] increased linearly as storage time increased, after an initial induction period of very low browning development. The slope of the linear browning development zone with time was an index of browning rate, and it was analyzed in relation to the initial color and the composition of honeys (moisture content, total nitrogen, total lipids and polyunsaturated fatty acids, fructose and glucose content). Of the analyzed variables, the initial color was the parameter which better defined the rate of darkening of honeys.

The geometric place of the relation between PI control parameters in Nash equilibrium with respect to dynamic parameters of a first order system was built. The Nash equilibrium was calculated with squared sum of error and squared sum of control signal as players, and the control parameter values as strategies. The geometric place allows the conjecture that exist an homeomorphism. The performance of the regulator in Nash equilibrium is shown.

Resolvers are robust and reliable transducers, working as rotary transformers, and are used for mechanical angle measurement. In the present work, the two stator windings of the resolver are excited with sine and cosine signals; the rotor winding produces a sinusoidal signal that presents a phase shift equal to the mechanical angle of the rotor. A resolver converter is developed to extract this mechanical angle in a novel way. The proposed method is based on a phase-locked loop technique that produces a measure of the angle that tracks the true mechanical angle of the rotor. The paper presents full details of the converter, Matlab simulation and experimental results. Institute of Electrical and Electronics;Engineers - Systems, Man and Cybernetics Society;University of Evry;GENOPOLE;IFSTTAR Scopus

The resolver is a mechanical angle and rotational speed transducer that operates as rotary transformer; its two stator windings are excited with sine and cosine AC signals and its rotor winding produces a sinusoidal signal that presents a phase shift relative to the excitation and equal to the mechanical angle of the rotor. A novel and simple resolver converter is developed in order to extract the mechanical angle from its signals. The proposed method is based on a phase-locked loop technique and produces a measure of the angle that tracks the true mechanical angle of the rotor. The paper presents full details of the converter, Matlab simulation and experimental results. Scopus

We demonstrate the hohlraum radiation temperature and symmetry required for ignition-scale inertial confinement fusion capsule implosions. Cryogenic gas-filled hohlraums with 2.2 mm-diameter capsules are heated with unprecedented laser energies of 1.2 MJ delivered by 192 ultraviolet laser beams on the National Ignition Facility. Laser backscatter measurements show that these hohlraums absorb 87% to 91% of the incident laser power resulting in peak radiation temperatures of T(RAD)=300 eV and a symmetric implosion to a 100 μm diameter hot core.

Twenty variables were recorded on 15 apricot (Prunus armeniaca L.) genotypes differing in growth habit and blossom time to detect possible associations among morphological and phonological traits. The widest range of variability observed among phenotypes was for fruit size and factors associated with adaptation to local conditions, such as blossom season and yield potential as expressed by number of buds, flowers, and fruits per length of fruiting spurs. The most important morphological traits correlated with fruit weight were tree growth habit, apical and basal diameter of fruiting spurs, and bud and leaf size. Multivariate analysis allowed tree and variable grouping, which might encompass the basic criteria for apricot breeding programs in central Mexico. More than 80% of the world apricot production is restricted to Mediterranean climates (Caccamisi et al., 1987; Westwood, 1975). Apricots could be cultivated commercially in other areas of the world to satisfy local demand. In the semiarid regions of Mexico, apricots have been grown for more than two centuries and show a wide range of adaptation, but produce relatively small fruit. With the exception of 'Canine' and 'San Castrese', which show a wider range of adaptation (C. Fideghelli, personal com- munication), apricot cultivars are highly specific in their ecolog- ical requirements (Bailey and Hough, 1975) and cannot be successfully cultivated away from their place of origin. Local breeding outside traditional growing regions should be encour- aged to widen the distribution and cultivation of apricots (Bailey and Hough, 1975). The early stages of any breeding program require germplasm collection and characterization. However, the information avail- able on apricot descriptors includes mainly varieties from the European group (Couranjou, 1977; Sansavini et al., 1987). They are based on a wide range of characteristics, such as tree vigor and growth habit, leaf size and shape, productivity (Brooks and Olmo, 1972; Couranjou, 1977; Fideghelli and Monastra, 1977), disease resistance (Crossa-Raynaud, 1969; Guerriero and Wat- kins, 1984), fruit quality (Brooks and Olmo, 1972; Couranjou, 1977; Fideghelli and Monastra, 1977; Guerriero and Watkins, 1984; Monastra et al., 1984), and isozyrne differences (Byrne and Littleton, 1989). More than three decades ago, Lapins et al. (1957) detected a high parent-offspring correlation for fruit size and flesh firm- ness, two of the most important traits related to fruit quality. However, with the exceptions of the report by Cociu (cited by Bailey and Hough, 1975) and the personal communication by C. Fideghelli and G. Della Strada (1991), very little information is available about simple associations between morphological traits and fruit quality in apricots. The use of multivariate analysis has been used successfully

Lawrence Livermore National Laboratory (LLNL) has been developing compact solid state lasers since the 1990's. One of the first lasers to be developed utilized flashlamp pumped architecture and neodymium glass as the laser gain media. In the early 2000's, a diode pumped version of the original flashlamp pumped laser was designed and built, responding to the requirements that a laser system for the military be compact in both size and weight while creating significant power (~100 kW) for the missions envisioned. This paper will discuss the evolution of solid state lasers at LLNL and provide a glimpse into the types of capabilities that could be achieved in the near future.

In the recent years there has been an increasing interest in low-dimensional thermoelectric materials such as superlattices, quantum dots and nanowires [1,2,3]. An enhancement in thermoelectric figure-of-merit, Z=σα2 /k, where α is the Seebeck coefficient, σ is electrical conductivity, and k is the thermal conductivity, is predicted due to increased density of states near Fermi level [4]. A large contribution to the enhancement of thermoelectric figure-of-merit in low-dimensional systems may come from thermal conductivity reduction due to increased scattering of heat carriers from interfaces. In this light, we are interested in thermal properties of Bi2 Te3 nanowires and carried out thermal diffusivity characterization of these nanowires embedded in an amorphous alumina template.Copyright © 2002 by ASME

A liquid chromatographic/mass spectrometric (LC/MS) electrospray confirmation method has been developed to confirm 4 ionophores (monensin, lasalocid, salinomycin, and narasin) in a variety of animal feeds using a single quadrupole mass spectrometer. The sodium ions of these compounds are dominant in the electrospray mass spectrum. Using optimized "in-source" collision induced dissociation, characteristic fragment ions seen previously using MS/MS can be observed. The drugs were extracted from the feed matrix using hexane-ethyl acetate and isolated using a silica solid-phase extraction cartridge. These ionophores were confirmed in both medicated feeds and nonmedicated feeds fortified with these drugs at the 1-50 ppm level. In addition, this method was used to confirm residues of monensin in a nonmedicated feed that was collected from a feed mill immediately after the production of a similar feed that was medicated with high levels of monensin.

A gas chromatographic (GC) method is presented for determining residues of chloramphenicol (CAP), florfenicol (FF), florfenicol amine (FFa), and thiamphenicol (TAP) in shrimp tissues, with meta-nitrochloramphenicol (mCAP) as the internal standard. The composited shrimp is extracted with basic ethyl acetate, followed by an acetonitrile-basic ethyl acetate mixture. This extract is centrifuged, filtered, evaporated, and reconstituted in water; the reconstituted extract is acidified, defatted with hexane, and passed through a propylsulfonic acid (PRS) and C18 solid-phase extraction (SPE) system. The C18 SPE column is eluted with methanol, and the PRS SPE column is eluted with basic MeOH plus counter ion. The combined eluates are evaporated, reconstituted in acetonitrile, and derivatized with Sylon BFT. After derivatization, the addition of toluene directly to the sample, followed by the addition of basic water, quenches the derivatization process. After centrifugation, the organic layer is carefully removed, and the analytes are determined by GC with electron capture detection. Shrimp tissues were fortified with fenicols (i.e., CAP, FF, FFa, and TAP) at 5, 10, 20, 40, and 80 ng/mL. Overall recoveries were 88, 101, 91, and 84% with overall interassay (between-day) variabilities (i.e., relative standard deviations) of 5.3, 9.4, 12.8, and 7.4% for CAP, FF, FFa, and TAP, respectively. The method detection limits were calculated as 0.7, 1.4, 2.4, and 1.3 ng/g (ppb) for CAP, FF, FFa, and TAP, respectively, based on a 10 g sample. The quantitation limit as determined empirically by this method is the lower limit of the standard curve, which is about 5 ng/g (ppb) for each analyte.

A liquid chromatographic (LC) method with fluorescence detection (FLD) is described for determining residues of the pesticide azamethiphos (AZA) in salmon tissue. The sample is extracted with ethyl acetate, centrifuged, dehydrated with anhydrous sodium sulfate, evaporated, reconstituted in water, and defatted with hexane. The aqueous phase is passed through a C18 solid-phase extraction (SPE) column. The SPE column is eluted with methanol, and the eluate is evaporated to dryness and then taken up in 10% acetonitrile (ACN) in water. The analyte is determined by LC using a C18 column, ACN-H2O (32 + 68) mobile phase, and FLD with excitation at 230 nm and emission at 345 nm. Composited salmon tissues were fortified with AZA at 5, 10, 21, 42, and 83 ng/g or ppb (target level, X = 10 ng/g). Overall recoveries were 86%, with between-day variability of 5.3%. The method detection limit was calculated as 1.2 ppb AZA based on a 5 g sample. The limit of quantitation as determined empirically by this method is the lower limit of the standard curve, approximately 5 ppb.

A multi-residue LC/MS method has been developed to confirm avermectin drug residues in several food matrices. Ivermectin (IVR), doramectin (DOR), eprinomectin (EPR) and moxidectin (MOX) are confirmed using atmospheric pressure chemical ionization (APCI) with negative ion detection and selected ion monitoring of three to four ions for each compound. The drug residues are extracted from tissue or milk using previously published procedures. IVR and DOR are confirmed at 20 ppb levels in fortified salmon muscle; IVR is also confirmed in tissue from salmon dosed with the drug. Residues of DOR, IVR, and EPR are confirmed in fortified milk at the 20 ppb level and in fortified beef liver at 40 ppb. Residues of MOX can also be confirmed in these matrices, but at slightly higher levels (40-80 ppb).

A gas chromatographic (GC) method is described for determining residues of chloramphenicol (CAP), florfenicol (FF), and thiamphenicol (TAP) in raw milk, with meta-nitrochloramphenicol (mCAP) as internal standard. Milk is extracted with acetonitrile, centrifuged, evaporated, reconstituted in water, and passed through a C18 solid-phase extraction (SPE) column. The SPE column is eluted with 60% methanol, and then the eluate is evaporated and derivatized with Sylon BFT ¿N,O-bis(trimethylsilyl)trifluoroacetamide [BSTFA]-trimethylchlorosilane [TMCS], 99 + 1¿. After derivatization, toluene is added directly to the sample, followed by water, to quench the derivatization process. After centrifugation, the organic layer is carefully removed. Analytes are determined by GC with electron capture detection (ECD). Milk was fortified with fenicols (the collective name for CAP, FF, and TAP) at 5, 10, 20, 40 and 80 ng/mL (target level = 10 ng/mL). Overall recoveries were 92, 100, and 104% for CAP, FF, and TAP, respectively. Overall interassay (between-day) variabilities were 6.1, 6.7, and 6.0% for CAP, FF, and TAP, respectively. Raw milk samples containing incurred residues of FF were also analyzed.