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Early recovery from alcohol use disorder (AUD) is commonly associated with high levels of negative affect, stress, and emotional vulnerability, which confer significant relapse risk. Emotion differentiation-the ability to distinguish between discrete emotions-has been shown to predict relapse after treatment for a drug use disorder, but this relationship has not been explored in individuals recovering from AUD.The current study used thrice daily random and up to thrice daily self-initiated ecological momentary assessment surveys (N = 42, observations = 915) to examine whether 1) moments of high affective arousal are characterized by momentary differences in emotion differentiation among individuals in the first year of a current AUD recovery attempt, and 2) individuals' average emotion differentiation would predict subsequent alcohol use measured by the timeline follow-back over a 3-month follow-up period.Multilevel models showed that moments (Level 1) of higher-than-average negative affect (p 0.001) and/or stress (p = 0.033) were characterized by less negative emotion differentiation, while moments of higher-than-average positive affect were characterized by greater positive emotion differentiation (p 0.001). At the between-person level (Level 2), participants with higher stress overall had lower negative emotion differentiation (p = 0.009). Linear regression showed that average negative, but not positive, emotion differentiation was inversely associated with percent drinking days over the subsequent 3-month follow-up period (p = 0.042). Neither form of average emotion differentiation was associated with drinking quantity.We found that for individuals in early AUD recovery, affective states are associated with acute shifts in the capacity for emotion differentiation. Further, we found that average negative emotion differentiation prospectively predicts subsequent alcohol use.

Research suggests that virtual reality (VR) experiences can be helpful as adjunctive tools in psychotherapy for some mental health conditions. VR is a computer-generated experience that produces a feeling of being immersed in a different environment. VR experiences could be useful in the treatment of substance use disorders, and several are currently being tested. However, few psychotherapists report using VR experiences in their practices, even when doing so is well-supported. Understanding key barriers and concerns about using VR among drug/alcohol counselors is important to ultimately encouraging adoption.Licensed counselors (Most clinicians (82%) believed they would be likely to use a VR experience in drug/alcohol counseling, and 81% believed it would be appropriate for most of their clients. A minority (19%) noted important concerns, including that their clients may be skeptical of it (15%), cost (14%), and space (10%). Those who had cost and space concerns were less likely to report high use intentions (Findings suggest that addictions counselors are eager to use VR, but key barriers should be addressed. VR developers should incorporate features to encourage trust among users, design experiences for small spaces, and explore ways of supporting the purchase of VR systems for counselors.

BACKGROUND: Alcohol craving is common among adolescents, stronger among those with more alcohol-related problems, and predicts drinking levels in their daily lives. Yet, the conditions that predict momentary changes in craving in real time among adolescents remain unclear. OBJECTIVES: This study examined interactive effects of momentary risk-taking propensity and affect on adolescents’ alcohol craving by leveraging ecological momentary assessment (EMA) methods. METHODS: Participants were 29 adolescents ages 15-19 years (55% female; 69% White; 10% Black; 17% Hispanic); 45% met criteria for alcohol dependence. Following a laboratory session that captured self-report and behavioral assessments, including the well-established Balloon Analogue Risk Task (BART: Lejuez et al., 2002), participants completed multiple daily assessments of alcohol craving, positive and negative affect, and risk propensity for approximately one week. Momentary risk propensity was captured in real-world settings via an EMA behavioral task (“Balloon Game”). RESULTS: Mixed-effects models with EMA reports (Level 1) nested within participants (Level 2) revealed the majority (74%) of variability in “Balloon Game” performance was due to within-person, momentary, fluctuations. Greater momentary positive affect predicted increased alcohol craving, but only when participants exhibited heightened risk-taking propensity. Negative affect did not influence the relation between momentary risk-taking and craving. CONCLUSIONS/IMPORTANCE: Momentary fluctuations in positive affect predicted acute increases in craving but only in moments when adolescents demonstrated higher levels of risk-taking propensity, as captured with an EMA-delivered behavioral task. Momentary risk-taking assessments offer new avenues to substantiate dominant theories on the driving mechanisms of craving and alcohol use among adolescents.

Flour beetles of the genus Palorus (Coleoptera: Tenebrionidae) are important secondary storage pests. Correct identification of these insects is urgently required for integrated pest management. However, traditional morphological classification methods cannot identify insect fragments or immature stages and require skilled taxonomists with training and experience. In this study, three Palorus species were distinguished with two molecular techniques; DNA barcoding and species-specific PCR based on the mitochondrial DNA cytochrome oxidase subunit I (COI) gene. Forty-nine individuals of Palorus subdepressus (Wollaston), Palorus ratzeburgi (Wissman) and Palorus cerylonoides (Pascoe) were collected from 19 different locations across rice processing factory, feed factory, flour mill and bulk storages China. The COI sequences were analyzed by K2P distances and neighbor-joining (NJ) tree for DNA barcoding. The results show that these three Palorus species can be successfully identified by DNA barcoding. For the species-specific PCR study, we designed specificity primer pairs for the three Palorus species and evaluated their sensitivity. The results showed that the three Palorus species can be identified by the species-specific PCR method. Our results indicated that the two techniques can be independently used to identify the Palorus species in China for integrated pest management and quarantine. This is the first time Palorus species have been identified using two molecular techniques and the P. ratzeburgi and P. cerylonoides data have filled a gap in BOLD and GenBank.

Data on incidence of resistance to phosphine over the last 20 years and factors associated with insect sample collection are stored in the Australian Grain Insect Resistance Database. The database was analysed using descriptive statistics, linear trend analysis and Bayesian hurdle modelling to gain insights into factors contributing to the development of strong resistance in Rhyzopertha dominica. Descriptive statistics indicated that strong resistance was significantly more common in central storages, particularly bunker storages, than on farms. Strong resistance in R. dominica was also associated with wheat, barley and sorghum but there was no significant link to any grain protectant or storage treatment chemical, other than phosphine. Highest frequency of strong resistance was found in northern New South Wales and no detections were made in Western Australia. In eastern Australia, trend analysis indicated that strong resistance detections increased steadily from the first detection in 1997 to about 8% of samples containing resistant insects in 2014. Weak resistance was detected in about 10% of samples in eastern Australia in the early 1990s but this increased rapidly to 40–50% by 1990, at the same time that industry use of phosphine greatly increased, and then to about 80% in 1995. Strong resistance was first detected in this species when weak resistance was diagnosed in close to 80% of population samples. The Bayesian hurdle model identified bunkers, silos and unsealed storages as being associated with development of strong resistance and sheds with a lower frequency. This model also identified an accelerated increase in resistance frequency of strong resistance from 2011 to present. The information gained from this analysis is being used to inform current and future management of resistance to phosphine.

In Australia, along with many other parts of the world, fumigation with phosphine is a vital component in controlling stored grain insect pests. However, resistance is a factor that may limit the continued efficacy of this fumigant. While strong resistance to phosphine has been identified and characterised, very little information is available on the causes of its development and spread. Data obtained from a unique national resistance monitoring and management program were analysed, using Bayesian hurdle modelling, to determine which factors may be responsible. Fumigation in unsealed storages, combined with a high frequency of weak resistance, were found to be the main criteria that led to the development of strong resistance in Sitophilus oryzae. Independent development, rather than gene flow via migration, appears to be primarily responsible for the geographic incidence of strong resistance to phosphine in S. oryzae. This information can now be utilised to direct resources and education into those areas at high risk and to refine phosphine resistance management strategies.

Nitridocobaltates Li3-2xCoxN, with Li3N-type layered structure, are promising compounds as negative electrode materials for Li-ion batteries. In the present paper, we report the first detailed broadband dielectric spectroscopy (BDS) study on lithiated transition metal nitrides. The ionic and electronic conductivities of Li3-2xCox□xN compounds (0 ≤ x ≤ 0.44) are investigated as a function of the concentration x of cobalt ions, cationic vacancies (□) and lithium ions. Dielectric and conductivity spectra were recorded within the frequency range of 60-1010 Hz from 200 to 300 K. Experimental results exhibit two types of electric conduction: the first one is due to lithium ion diffusion (for 0 ≤ x ≤ 0.25) and the second one due to electronic transfers (for x ≥ 0.3). Furthermore, two percolation transitions are evidenced and associated with 3D ionic transfers (threshold at x ≈ 0.11) on the one hand and 2D electronic transfers (threshold at x ≈ 0.30) on the other hand. Upon increasing the frequency, dielectric relaxations appear from larger to smaller sample scales. These successive polarizations appear with increasing frequency in the following order: (a) sample/silver paint interface; (b) particles (aggregates of grains); (c) grains (crystallites); (d) local ionic and electronic motions within the grains. Evolutions of dielectric relaxation parameters (dielectric strength and relaxation frequency) with Co content confirm the two percolation transitions. Surprisingly, the grain conductivity has a large discontinuity immediately below the electronic percolation threshold where any local- and long-range ionic movement disappears without electronic transfer. This discontinuity would be due to a narrow transition from ionic to electronic conduction when x increases.

Research on alcohol use depends heavily on the validity of self-reported drinking. The present paper presents data from 647 days of self-monitoring with a transdermal alcohol sensor by 60 young adults. We utilized a biochemical measure, transdermal alcohol assessment with the WrisTAS, to examine the convergent validity of three approaches to collecting daily self-report drinking data: experience sampling, daily morning reports of the previous night, and 1-week timeline follow-back (TLFB) assessments. We tested associations between three pharmacokinetic indices (peak concentration, area under the curve (AUC), and time to reach peak concentration) derived from the transdermal alcohol signal and within- and between- person variation in alcohol dependence symptoms. The WrisTAS data corroborated 85.74% of self-reported drinking days based on the experience sampling data. The TLFB assessment and combined experience sampling and morning reports agreed on 87.27% of drinking days. Drinks per drinking day did not vary as a function of wearing or not wearing the sensor; this indicates that participants provided consistent reports of their drinking regardless of biochemical verification. In respect to self-reported alcohol dependence symptoms, the AUC of the WrisTAS alcohol signal was associated with dependence symptoms at both the within- and between- person level. Furthermore, alcohol dependence symptoms at baseline predicted drinking episodes characterized in biochemical data by both higher peak alcohol concentration and faster time to reach peak concentration. The results support the validity of self-report alcohol data, provide empirical data useful for optimal design of daily process sampling, and provide an initial demonstration of the use of transdermal alcohol assessment to characterize drinking dynamics associated with risk for alcohol dependence.

A large data set of XAS (X-ray Absorption Spectroscopy) Manganese K-edge spectra has been collected operando and studied upon the electrochemical oxidation of the promising Li-ion battery anode material Li

We explored the utility of analyzing within- and between-balloon response patterns on a balloon analogue task (BAT) in relation to overall risk scores, and to a choice between a small guaranteed cash reward and an uncertain reward of the same expected value. Young adults (n = 61) played a BAT, and then were offered a choice between $5 in cash and betting to win $0 to $15. Between groups, pumping was differentially influenced by explosions and by the number of successive unexploded balloons, with risk takers responding increasingly on successive balloons after an explosion. Within-balloons, risk takers showed a characteristic pattern of constant high rate, while non-risk takers showed a characteristic variable lower rate. Overall, results show that the higher number of pumps and explosions that characterize risk takers at a molar level, result from particular forms of adaptation to the positive and negative outcomes of choices seen at a molecular level.

BACKGROUND Control of pests in stored grain and the evolution of resistance to pesticides are serious problems worldwide. A stochastic individual-based two-locus model was used to investigate the impact of two important issues, the consistency of pesticide dosage through the storage facility and the immigration rate of the adult pest, on overall population control and avoidance of evolution of resistance to the fumigant phosphine in an important pest of stored grain, the lesser grain borer. RESULTS A very consistent dosage maintained good control for all immigration rates, while an inconsistent dosage failed to maintain control in all cases. At intermediate dosage consistency, immigration rate became a critical factor in whether control was maintained or resistance emerged. CONCLUSION Achieving a consistent fumigant dosage is a key factor in avoiding evolution of resistance to phosphine and maintaining control of populations of stored-grain pests; when the dosage achieved is very inconsistent, there is likely to be a problem regardless of immigration rate. © 2012 Society of Chemical Industry

A large number of compounds including lignin, phospholipids, pectin, DNA, mRNA, and proteins require methyl groups for their functionality. A detailed study of the expression and activities of two enzymes, adenosine kinase (ADK) and S-adenosylhomocysteine hydrolase (SAHH), which are both required for the maintenance and recycling of S-adenosylmethionine-dependent methylation in plants, was carried out. The abundance and tissue localization of ADK and SAHH transcripts and protein were monitored along with their enzyme activities in leaves, stems, buds, siliques, and roots of Arabidopsis. In all but roots and seed coats, the transcript abundance of ADK and SAHH fluctuated co-ordinately, matching changes in their protein and enzyme activities. To evaluate whether this expression pattern was associated with methyl recycling, the protein content and distribution of S-adenosylmethionine synthetase and phosphoethanolamine N-methyltransferase, a key methyltransferase involved in phospholipid synthesis, were investigated. These were found to accumulate in a pattern similar to ADK and SAHH. ADK and SAHH protein and transcript amounts were shown to fluctuate similarly in tissues accumulating lignin. Additionally, the amounts of ADK and SAHH mRNAs were also found at high levels in inflorescence meristems likely to support their higher rates of cell division. Thus, the results point to a co-ordinated and probably transcriptional regulation of these genes in most organs of Arabidopsis; SAHH abundance is distinctly higher in seeds and roots which suggests it may have a non-methyl-related role in these organs.

Although it is well accepted that cytokinins (CKs) regulate processes such as leaf senescence and stomatal conductance, data on CKs in the canopy of mature trees are lacking in the literature. Here we report the first in situ sampling for determination of CKs in mature sugar maple (Acer saccharum) canopy layers. The upper canopy showed a distinct seasonal pattern in total CK content, while the lower canopy remained relatively unchanged.

Small local populations of Silene alba, a short-lived herbaceous plant, were sampled in 1994 and again in 1999. Sampling included estimates of population size and genetic diversity, as measured at six polymorphic allozyme loci. When averaged across populations, there was very little change between samples (about three generations) in population size, measures of within-population genetic diversity such as number of alleles or expected heterozygosity, or in the apportionment of genetic diversity within and among populations as measured by F(st). However, individual populations changed considerably, both in terms of numbers of individuals and genetic composition. Some populations doubled in size between samples, while others shrank by more than 75%. Similarly, expected heterozygosity and allele number increased by more than two-fold in individual populations and decreased by more than three-fold in others. When population-specific change in number and change in measures of genetic diversity were considered together, significant positive correlations were found between the demographic and genetic variables. It is speculated that some populations were released from the demographic consequences of inbreeding depression by gene flow.

The alpine tundra ecotype of Stellaria longipes is characterized by a dwarf phenotype, whereas the prairie ecotype can be semidwarf or highly elongated depending on its environment. Related to their ability to elongate, these ecotypes also show divergent abilities to produce and respond to ethylene. The prairie ecotype produces a strong daily rhythm of ethylene, which is maintained even following stress events such as wind. The alpine ecotype exhibits a much less pronounced rhythm but greatly increases ethylene production in response to stress. We investigated what differences in ethylene synthesis might be responsible for the ability of the prairie ecotype to produce a large and regular daily rhythm of ethylene production, which in the alpine ecotype is weaker or sometimes absent. Levels of the immediate precursor to ethylene, 1-aminocyclopropane-1-carboxylate (ACC), and its major conjugate, malonyl ACC (MACC) showed no rhythm across the course of a day. Moreover ACC levels remained stable during an entire growth cycle (21 days) in the prairie ecotype, even though ethylene is known to increase especially during periods of rapid elongation. By contrast, assays of ACC oxidase performed in vivo and in vitro showed rhythms of activity similar to those of ethylene production observed in the prairie ecotype. However, the levels of ethylene produced in the ACC oxidase assays were considerably higher than levels of ethylene normally produced by unstressed plants, and the rhythm of ACC oxidase activity was observed in both ecotypes, despite the fact that alpine Stellaria longipes exhibits a less pronounced ethylene rhythm. Thus, we concluded that although ACC oxidase activity may partially account for rhythmic production of ethylene in prairie ecotypes, other controlling factors such as spatial separation of ACC from ACC oxidase should be investigated. Key words: ACC oxidase, ecotypes, ethylene, phenotypic plasticity, rhythmicity, Stellaria longipes.

Apoptosis is a form of programmed cell death which exhibits highly distinctive morphology. Research activity in this area has increased substantially in recent years, primarily due to the realisation that disregulation of apoptosis is involved in the development of a number of pathological conditions, including cancer and AIDS. However, it is now clear that apoptosis also represents the dominant form of cell death during the culture of industrially important cell lines. This review focuses on the induction of apoptosis during industrial cell cultures as well as the effects of the apoptosis suppresser gene bcl-2 on cell survival in conditions relevant to bioreaction environments. We also present new data which demonstrates that bcl-2 can protect cells from apoptosis induced by oxygen deprivation, a finding which has important implications for large scale and intensive cultivation of cells. We also describe experiments which suggest that bcl-2 can reduce the specific nutrient consumption rate of cells.

Sf9 insect cells have been cultivated in paired agitated 1.4 L bioreactors with and without Pluronic F-68 and with and without sparging. The results are reported and, as appropriate, compared to those of hybridoma culture. Without sparging, the cells grew well at agitator speeds from 100 to 400 rpm (equivalent to a realistic range of specific energy dissipation rates). At the higher speeds, a small reduction in growth rate and maximum viable cell concentration was observed. This reduction was shown not to be dependent on the energy dissipation rate but to be due to bubble entrainment. These results are rather similar to those found with hybridoma cells. However, unlike hybridoma cells which grow like unsparged controls when sparged at 0.007 vvm, these insect cells at such a sparge rate show a significant reduction in growth rate and in maximum cell number. This reduction due to the presence of bubbles, whether from head space entrainment or from sparging, could be eliminated by the presence of Pluronic F-68. These insect cells have then also been infected with recombinant or wild type AcNPV. Agitation had no effect on the rate of infection, but higher levels of MOI enhanced it. Both findings support a diffusion mechanism as previously. The presence of Pluronic F-68 did not have any impact on the rate of infection and was able to prevent cell damage while agitating and sparging infected cells.

The abilities of various methods of oxygenation to meet the demands of high-cell-density culture were investigated using a spin filter perfusion system in a bench-top bioreactor. Oxygen demand at high cell density could not be met by sparging with air inside a spin filter (oxygen transfer values in this condition were comparable with those for surface aeration). Sparging with air outside a spin filter gave adequate oxygen transfer for the support of cell concentrations above 10(7) ml-1 in fully aerobic conditions but the addition of antifoam to control foaming caused blockage of the spinfilter mesh. Bubble-free aeration through immersed silicone tubing with pure oxygen gave similar oxygen transfer rates to that of sparging with air but without the problems of bubble damage and fouling of the spin filter. A supra-optimal level of dissolved oxygen (478% air saturation) inhibited cell growth. However, cells could recover from this stress and reach high density after reduction of the dissolved oxygen level to 50% air saturation.

Exposure of animal cells to intense hydrodynamic forces exerted in turbulent capillary flow, and by controiled agitation and aeration, resulted in preferential destruction of S and G(2) cells and the extent of destruction of these cells was dependent upon the intensity of the action. The loss of these cells was possibly due to their larger size. However, the appearance of large numbers of membrane-bound vesicular structures similar to apoptotic bodies as well as cells with low DNA stainability (in a sub-G(1) peak) suggested that the action of adverse hydrodynamic forces on these large cells may at least in part be to induce an apoptotic response. (c) 1995 John Wiley & Sons, Inc.

The incidence of apoptotic and necrotic cell death was compared in CHO, SF9 insect cells and murine plasmacytoma (J558L) and hybridoma (TB/C3) cells during in vitro cultivation in batch cultures. Acridine orange staining and fluorescence microscopy enabled the visualization of a classic morphological feature of apoptotic cell, the presence of condensed and/or fragmented chromatin. DNA gel electrophoresis was employed to show an additional characteristic of the process, the endonuclease-mediated fragmentation of DNA into multiples of 180 base pairs. The levels of apoptosis at the end of batch cultures of plasmacytoma and hybridoma cell lines were found to be 60% and 90% of total dead cells, respectively. However, employing the above-mentioned techniques, the biochemical and morphological features of apoptosis were not found in CHO and SF9 insect cells. Some factors affecting the induction of apoptosis during the batch culture of the hybridoma and plasmacytoma cell lines were identified. The most effective inducer was found to be glutamine limitation, followed by (in order of importance) serum limitation, glucose limitation, and ammonia toxicity. Blockage of the cell cycle of the plasmacytoma and hybridoma cells using thymidine resulted in the induction of apoptosis. This has important implications for the development of cell culture processes that minimize cell division and thereby increase specific productivity. © 1994 John Wiley & Sons, Inc.

Using two ecotypes of Stellaria longipes an alpine form with low plasticity and a prairie form with high plasticity, we investigated whether ethylene was involved in the response to wind stress and might be important in controlling plasticity of stem elongation. Stem growth inhibition was positively correlated with concentration of ethephon application and elevation in ambient ethylene in alpine ecotypes, whereas stem growth in prairie plants was stimulated by low ethephon concentrations. When treated with high AVG, the effects were reversed: alpine plant growth was promoted and prairie plant growth was inhibited. Prairie plants exhibited a daily rhythm in ethylene evolution which increased and peaked at 1500 h, and which was absent in alpine plants. Ethylene evolution did not change significantly during the first 2 weeks of growth in alpine plants, whereas ethylene in prairie plants increased significantly during periods of rapid stem elongation. Wind treatment inhibited growth in both ecotypes, but only alpine plants showed a recovery of growth to control levels when wind stressed plants were pretreated with STS. In addition, only alpine plants showed an increase in ethylene evolution in response to wind simulation, whereas prairie plant ethylene evolution did not deviate from rhythms observed in unstressed plants. We concluded that ethylene dwarfs stems in alpine S. longipes in response to wind stress. However, low levels of ethylene may stimulate growth in prairie ecotypes and act independently of wind stress intensity. The contrasting ability to synthesize and respond to ethylene can account for part of the difference in plasticity documented between the two ecotypes.

The exponential cells ofBacillus cereus immobilized in calcium alginate and spun into microcylindrical particles were used in a fluidized-bed reactor for continuous synthesis of thermostable α-amylase. The reactor was operated over a period of 30 d with a dilution rate of 0.33 h-1, producing 1000–1200 U/mL of enzyme. The productivity of the reactor was in the range of 330–396 kU/h. A 20-fold increase in the productivity with respect to batch fermentation with free cells was attained.

Multivariate principal components analyses of seven morphological characters of a putative hybrid population (located at Plateau Mountain, Kananaskis, Alberta) indicated the occurrence of hybridization between Stellaria longipes and Stellaria borealis. Although the putative hybrid population had intermediate morphology between the two species, it clustered closer to that of S. longipes. Electrophoretic analysis of 15 isozyme loci confirmed that the putative hybrid population was a result of hybridization and possibly introgression. Unique alleles of both species were present in the hybrid, although they were more often attributable to S. longipes. The genetic identity and the level of genetic variability of the hybrid was of an intermediate level between the two species, but closer to that of S. longipes. Key words: natural hybridization, Stellaria longipes, Stellaria borealis, introgression, isozymes.

The question is addressed as to whether observed parameter(s) characterizing single bubble burst (bubble jet height and speed) can be used to predict cell damage in sparged animal cell cultures. Bubble burst profiles are examined in the presence of realistic concentrations of fetal calf serum (FCS) or Pluronic F-68 using a high-speed video technique. The damage to TBC3 hybridoma cells from bubble sparging, characterized as a first-order decline, is reduced by even very small concentrations of both FCS and Pluronic F-68, but neither single bubble burst parameters nor surface properties give usable correlations with death rate constants.copy 1999 John WileySons, Inc.

Cell lines derived from the hemopoetic lineages are widely used as hosts for the production of biologicals. These cell lines have been demonstrated to undergo high levels of the active death program commonly referred to as apoptosis. The effects of overexpression of the apoptosis suppressor gene bcl-2 on the properties of a Burkitt lymphoma were compared with the control cell line (transfected with a negative control plasmid) under a variety of conditions relevant to cell culture production technology. In stationary batch cultures, there was a clear reduction in both the rate of total cell death and the level of apoptosis during the decline phase of the bcl-2 transfected cell cultures as compared with that of the control cell cultures. Nutrient analysis revealed that the onset of death during the control cell cultures occurred following complete exhaustion of glutamine. However, the bcl-2 transfected cell cultures continued to grow even though glutamine had been exhausted, and a significant decline in viability only occurred when glucose had also been completely exhausted.When cells were cultured in suspension without prior adaptation, the bcl-2 transfected cells grew significantly better, suggesting that the bcl-2 gene protected the cells from apoptosis triggered by either the lack of substrate or the hydrodynamic environment. Fluorescence microscopy revealed that death of the control cells was almost entirely by apoptosis, whereas death was almost exclusively by necrosis in the delayed decline phase of the transfected cell cultures. In both instances, death occurred before total exhaustion of glucose and glutamine.The induction of apoptosis following growth arrest is a major impediment to the development of culture strategies that optimize specific productivity by reducing the growth rate. Results presented here suggest that suppression of apoptosis by bcl-2 under the condition of excess thymidine allows the maintenance of cells in a growth-arrested state for much longer than would otherwise be possible.When cells were transferred to a range of commercial serum-free media, cell growth was, in all cases, much better for the bcl-2 transfected cell line. Moreover, when cells were cultivated in glutamine-free medium, the control cells exhibited a decrease in viable cell number within the first 24 h whereas, for the bcl-2 transfected cell cultures, viable cell number did not exhibit any clear decrease until after 75 h. Clearly, these results indicate that the metabolic engineering approach can be used to alter advantageously the survival and proliferative capacity of cells in cell culture environments. (c) 1996 John WileySons, Inc.

Dispersion and mass-transfer characteristics and fluidization parameters influencing the performance of a small pilot-plant immobilized enzyme reactor are evaluated. The suitability of a dispersed plug-flow model to predict the conversions obtained in the enzymatic reaction (starch → glucose) catalyzed by amyloglucosidase immobilized to solid and porous carriers is assessed. The performance of a fluidized-bed reactor is compared on the basis of a normalized residence time with that of a fixed bed and found to be superior.

The linear and nonlinear response to a microwave electromagnetic field of two c-axis oriented polycrystalline samples of the newly discovered superconductor CaC6 (Tc = 11.5 K) is studied in the superconducting state down to 2 K. The surface resistance Rs and the third order intermodulation distortion, arising from a two-tone excitation, have been measured as a function of temperature and microwave circulating power. Experiments are carried out using a dielectrically loaded copper cavity operating at 7 GHz in a "hot finger" configuration. The results confirm recent experimental findings that CaC6 behaves as a weakly-coupled, fully gapped, superconductor. The weak power dependence of Rs encourages a further investigation of this novel superconductor as a possible alternative to Nb in specific microwave applications., 8 pages, 4 figures, submitted to Appl. Phys. Lett