基于植物重组蛋白产量提高的研究进展

重组蛋白为疾病治疗提供了新手段,同时创造了可观的经济效益。利用经济作物(主要是烟草)、谷类作物、豆科作物和蔬菜作物生产具有药用价值的重组蛋白是“分子农业”最热门的研究内容。尽管许多重组蛋白已在植物中表达,但只有一小部分已成功投入使用。为了极大地克服限制植物生产重组蛋白发展的问题,研究人员改进表达系统以增加重组蛋白的产量。本文从分析植物产生重组蛋白产量低和/或生物活性低等问题入手,综述了近些年来解决这些问题的优化策略,同时提出了提高植物生产重组蛋白产量的研究方向。     

Depolarization of the Client's Moral Position as a Method of Psychological Consultation

In an earlier article we attempted to construct a universal psychotherapeutic theory. On the basis of an analysis of the works of Freud (1923), Carl Rogers (1965), and V. Frankel (1990), we distinguished some universal principles in explaining the mechanisms of formation of neurotic symptoms and formulated, in a more general way, the principal goal of psychotherapy of neuroses (Kapustin, 1993). We also showed that these principles can be used to explain the mechanisms of a broader range of clients' problems in psychological consultation (Kapustin, 1994). We regarded the purpose of a psychological consultation for this range of problems as a somewhat universal one, independent of the content of the problems or of the symptoms accompanying their mental disorders. Further development of our theory will inevitably require the development of a technique of consultation that fits the language and the concepts of the given theory.     

On a heuristic point of view concerning the expression of numerous genes during the cell cycle

The current model of the eukaryotic cell cycle proposes that numerous genes are expressed at different times during the cell cycle. The existence of myriad control points for gene expression leads to theoretical and logical problems for cell cycle control. Each expressed gene requires a control element to appear in a cell-cycle specific manner; this control element requires another control element and so on, ad infinitum. There are also experimental problems with the current model based on ineffective synchronization methods and problems with microarray measurements of mRNA. Equally important, the efficacy of mRNA variation in affecting changes in protein content is negligible. An alternative view of the cell cycle proposes cycle-independent, invariant accumulation of mRNA during the cell cycle with decreases of specific proteins occurring only during the mitotic period of the cell cycle.     

Homology a personal view on some of the problems

There are many problems relating to defining the terminology used to describe various biological relationships and getting agreement on which definitions are best. Here, I examine 15 terminological problems, all of which are current, and all of which relate to the usage of homology and its associated terms. I suggest a set of definitions that are intended to be totally consistent among themselves and also as consistent as possible with most current usage.     

An artificial maximum neural network: a winner-take-all neuron model forcing the state of the system in a solution domain

A maximum neuron model is proposed in order to force the state of the system to converge to the solution in neural dynamics. The state of the system is always forced in a solution domain. The artificial maximum neural network is used for the module orientation problem and the bipartite subgraph problem. The usefulness of the maximum neural network is empirically demonstrated by simulating randomly generated massive nstances (examples) in both problems. In randomly generated more than one thousand instances our system always converges to the solution within one hundred iteration steps regardless of the problem size. Our simulation results show the effectiveness of our algorithms and support our claim that one class of NP-complete problems may be solvable in a polynomial time.     

Controlling the number of HIV infectives in a mobile population

The spread of the human immunodeficiency virus (HIV) depends prominently on the migration of people between different regions. An important consequence of this population mobility is that HIV control strategies that are optimal in a regional sense may not be optimal in a national sense. We formulate various mathematical control problems for HIV spread in mobile heterosexual populations, and show how optimal regional control strategies can be obtained that minimize the national spread of HIV. We apply the cross-entropy method to solve these highly multi-modal and non-linear optimization problems. We demonstrate the effectiveness of the method via a range of experiments and illustrate how the form of the optimal control function depends on the mathematical model used for the HIV spread.     

Unravelling the dynamics of organisms in a changing world using ecological modelling

Understanding and predicting the dynamics of organisms is a central objective in ecology and conservation biology, and modelling provides a solution to tackling this problem. However, the complex nature of ecological systems means that for a thorough understanding of ecological dynamics at hierarchical scales, a set of modeling approaches need to be adopted. This review illustrates how modelling approaches can be used to understand the dynamics of organisms in applied ecological problems, focussing on mechanistic models at a local scale and statistical models at a broad scale. Mechanistic models incorporate ecological processes explicitly and thus are likely to be robust under novel conditions. Models based on behavioural decisions by individuals represent a typical example of the successful application of mechanistic models to applied problems. Considering the data-hungry nature of such mechanistic models, model complexity and parameterisation need to be explored further for a quick and widespread implementation of this model type. For broad-scale phenomena, statistical models play an important role in dealing with problems that are often inherent in data. Examples include models for quantifying population trends from long-term, large-scale data and those for comparative methods of extinction risk. Novel statistical approaches also allow mechanistic models to be parameterised using readily obtained data at a macro scale. In conclusion, the complementary use and improvement of multiple model types, the increased use of novel model parameterisation, the examination of model transferability and the achievement of wider biodiversity information availability are key challenges for the effective use of modelling in applied ecological problems.     

A case of the adoption of an infant chimpanzee by a suckling foster chimpanzee

Chimpanzees in captivity have grown up in a rather unnatural social environment and there frequently are problems when they have to nurse their own offspring. It is most remarkable that a chimpanzee mother in a captive colony, who had lost her child almost immediately after birth, adopted without problems a five-week-old infant, which had been reared by humans from the day of its birth. Successful adoption has not been reported for feral chimpanzees; similar cases in captivity are not known.     

Competition in the presence of a lethal external inhibitor

The study considers two organisms competing for a nutrient in an open system in the presence of an inhibitor (or toxicant). The inhibitor is input at a constant rate and is lethal to one competitor while being taken up by the other without harm. This is in contrast to previous studies, where the inhibitor decreases the reproductive rate of one of the organisms. The mathematical result of the lethal effect, modeled by a mass action term, is that the system cannot be reduced to a monotone dynamical system of one order lower as is common with chemostat-like problems. The model is described by four non-linear, ordinary differential equations and we seek to describe the asymptotic behavior as a function of the parameters of the system. Several global exclusion results are presented with mathematical proofs. However, in the case of coexistence, oscillatory behavior is possible and the study proceeds with numerical examples. The model is relevant to bioremediation problems in nature and to laboratory bio-reactors.     

Transfer of medical technology from a developed to a developing country

Medical care is increasingly dependent on technology, but what are the problems involved in the transfer of technology from a developed to a developing country? What are the administrative, personnel and engineering problems? We address these questions in the context of our experience of transferring the medical technology and knowledge necessary for the development of nuclear medicine facilities in Kuwait.     

Instability of the distal radio-ulnar joint: stabilization by a Gore-Tex ligament.

Diagnosis and treatment of problems caused by instability of the distal radio-ulnar joint are complex. In this retrospective study, the results of a uniform procedure by using a Gore-Tex ligament for stabilization of the distal radio-ulnar joint are presented. In eight patients, nine wrists were operated on. The mean age of the patients was 35 years. The dominant side was involved in six patients. The mean follow-up was 3.4 years. Three of nine wrist problems were of spontaneous onset. In these wrists, the final results were excellent. The other six wrists were operated on for problems after trauma: four patients after soft-tissue injury, one patient after distal radius fracture, and one patient after forearm fracture. Among these cases, one result was excellent, four were good, and another one was fair.     

Features of the chemical models of a nonideal atomic plasma at high temperatures

The equation of state for a hydrogen plasma at high temperatures is considered in a physical and a chemical model. A simple expression is obtained that relates the pressure correction in chemical models to the high-temperature limit of the atom partition function. This expression ensures a correct asymptotic behavior of the equation of state in the high-temperature limit. It is explained why the familiar astrophysical model of Hummer, Mihalas, and Däppen, as applied to helioseismology, yields worse results than a physical model. A modification of the astrophysical model is proposed that makes it possible to use the nearest neighbor approximation to calculate the atom partition function in chemical models in solving astrophysical problems and problems concerning low-temperature plasmas.     

Evaluation of a particle swarm algorithm for biomechanical optimization

Optimization is frequently employed in biomechanics research to solve system identification problems, predict human movement, or estimate muscle or other internal forces that cannot be measured directly. Unfortunately, biomechanical optimization problems often possess multiple local minima, making it difficult to find the best solution. Furthermore, convergence in gradient-based algorithms can be affected by scaling to account for design variables with different length scales or units. In this study we evaluate a recently-developed version of the particle swarm optimization (PSO) algorithm to address these problems. The algorithm's global search capabilities were investigated using a suite of difficult analytical test problems, while its scale-independent nature was proven mathematically and verified using a biomechanical test problem. For comparison, all test problems were also solved with three off-the-shelf optimization algorithms--a global genetic algorithm (GA) and multistart gradient-based sequential quadratic programming (SQP) and quasi-Newton (BFGS) algorithms. For the analytical test problems, only the PSO algorithm was successful on the majority of the problems. When compared to previously published results for the same problems, PSO was more robust than a global simulated annealing algorithm but less robust than a different, more complex genetic algorithm. For the biomechanical test problem, only the PSO algorithm was insensitive to design variable scaling, with the GA algorithm being mildly sensitive and the SQP and BFGS algorithms being highly sensitive. The proposed PSO algorithm provides a new off-the-shelf global optimization option for difficult biomechanical problems, especially those utilizing design variables with different length scales or units.     

Optimal situation control for a biosynthetic process on the basis of a prediction filter

A concept for the periodic control of fermentation processes is presented which realizes a strategy with maximal material and energetic efficiencies. The program system for situation control, problems of selection of the feature vector and the experimental results are discussed.     

Reducing the worst case running times of a family of RNA and CFG problems, using Valiant's approach

Background

RNA secondary structure prediction is a mainstream bioinformatic domain, and is key to computational analysis of functional RNA. In more than 30 years, much research has been devoted to defining different variants of RNA structure prediction problems, and to developing techniques for improving prediction quality. Nevertheless, most of the algorithms in this field follow a similar dynamic programming approach as that presented by Nussinov and Jacobson in the late 70's, which typically yields cubic worst case running time algorithms. Recently, some algorithmic approaches were applied to improve the complexity of these algorithms, motivated by new discoveries in the RNA domain and by the need to efficiently analyze the increasing amount of accumulated genome-wide data.

Results

We study Valiant's classical algorithm for Context Free Grammar recognition in sub-cubic time, and extract features that are common to problems on which Valiant's approach can be applied. Based on this, we describe several problem templates, and formulate generic algorithms that use Valiant's technique and can be applied to all problems which abide by these templates, including many problems within the world of RNA Secondary Structures and Context Free Grammars.

Conclusions

The algorithms presented in this paper improve the theoretical asymptotic worst case running time bounds for a large family of important problems. It is also possible that the suggested techniques could be applied to yield a practical speedup for these problems. For some of the problems (such as computing the RNA partition function and base-pair binding probabilities), the presented techniques are the only ones which are currently known for reducing the asymptotic running time bounds of the standard algorithms.     

Perseveration, inhibition and the prefrontal cortex: a new look.

Perseverative actions are often the result of inhibitory problems; however, inhibitory problems do not always lead to perseverative actions. Some problems of inhibition have been attributed to immaturity of, or severe damage to, the prefrontal cortex. Research in this area has generally failed both to take into account species differences in prefrontal function that lead to different perseverative errors and to distinguish between perseverative errors that arise from a failure to inhibit salient emotions or motivational drives and errors that arise from an inability to engage in conceptual change. Recent studies on humans, chimpanzees, rhesus macaques, Japanese macaques, cotton-top tamarins and marmosets support this notion.     

Assessing the impact of anosmia: review of a questionnaire's findings

The inability to detect odours, anosmia, can cause profound psychological effects resulting in feelings of physical and social vulnerability and victimization. In addition, there may be unhappiness related to the loss of the ability to detect pleasurable food smells and, as a consequence, anosmics may develop problems relating to eating. These profound effects arise from a condition which can have a rapid onset and a very poor prognosis for recovery, and are largely treated with a lack of sympathy and indifference by people with normal olfactory ability. In an attempt to educate, inform and help sufferers, a questionnaire was developed in the early 1980s and sent to those who contacted the Warwick Olfaction Research Group. The responses from this questionnaire form the basis of this review. Feelings of personal isolation, lack of interest in eating and emotional blunting were common responses from these sufferers and it seems that we still have some way to go before an adequate recognition of problems associated with anosmia is gained by the general population and, more importantly, within the medical profession.     

Administrative issues in the management of a sports medicine program.

Sports medicine is a subspecialty of medicine which has recently gained prominence in this country. It is usually practiced in conjunction with a specific program of sports medicine in an institutional setting, such as a university. This article describes the integration of sports medicine and the department of athletics at Yale University. The athletic medicine department, as it is called, treats both the injuries and other medical problems of students participating in the organized athletic programs, be they intercollegiate or intramural, which are organized by the University. Problems that arise both medically, such as when to play an injured player, and administratively, such as who should supervise trainers, are discussed. Guidelines are given for choosing the director of this program, as are examples of how to deal with problems between the physicians and the coaches.     

Microduplication 22q11.2: a description of the clinical, developmental and behavioral characteristics during childhood

Microduplication 22q11.2 is a recently discovered genomic disorder. So far, targeted research on the cognitive and behavioral characteristics of individuals with this microduplication is limited. Therefore, 11 Flemish children (3-13 years old) with a microduplication 22q 1.2 were investigated in order to describe their clinical, developmental and behavioral characteristics. We measured their general intelligence, visual-motor capacities, attention, behavioral problems and characteristics of autism. In addition, there was an interview with the parents on developmental history and we reviewed available information from other specialists. The results show that the cognitive and behavioral phenotype of the children with microduplication 22q.11.2 is very wide and heterogeneous. Some of the children have a cognitively nearly normal development whereas others are more severely affected. All children had some degree of developmental delay and some of them have an intellectual disability. The most common clinical features include congenital malformations such as heart defects and cleft lip, feeding problems, hearing impairment and facial dysmorphism. The most common non-medical problems are learning difficulties, motor impairment, attention deficits, social problems and behavioral problems. There is no correlation between the size of the duplication and the phenotype.     

Efficacy of the alcohol use disorders identification test as a screening tool for hazardous alcohol intake and related disorders in primary care: a validity study.

OBJECTIVE: To determine the properties of the alcohol use disorders identification test in screening primary care attenders for alcohol problems. DESIGN: A validity study among consecutive primary care attenders aged 18-65 years. Every third subject completed the alcohol use disorders identification test (a 10 item self report questionnaire on alcohol intake and related problems) and was interviewed by an investigator with the composite international diagnostic interview alcohol use module (a standardised interview for the independent assessment of alcohol intake and related disorders). SETTING: 10 primary care clinics in Verona, north eastern Italy. PATIENTS: 500 subjects were approached and 482 (96.4%) completed evaluation. RESULTS: When the alcohol use disorders identification test was used to detect subjects with alcohol problems the area under the receiver operating characteristic curve was 0.95. The cut off score of 5 was associated with a sensitivity of 0.84, a specificity of 0.90, and a positive predictive value of 0.60. The screening ability of the total score derived from summing the responses to the five items minimising the probability of misclassification between subjects with and without alcohol problems provided an area under the receiver operating characteristic curve of 0.93. A score of 5 or more on the five items was associated with a sensitivity of 0.79, a specificity of 0.95, and a positive predictive value of 0.73. CONCLUSIONS: The alcohol use disorders identification test performs well in detecting subjects with formal alcohol disorders and those with hazardous alcohol intake. Using five of the 10 items on the questionnaire gives reasonable accuracy, and these are recommended as questions of choice to screen patients for alcohol problems.