Design of heat exchanger network based on entransy theory

The heat exchanger network(HEN) synthesis problem based on entransy theory is analyzed. According to the characteristics of entransy representation of thermal potential energy, the entransy dissipation represents the irreversibility of the heat transfer process, the temperature difference determines the entransy dissipation, and four HEN design steps based on entransy theory are put forward. The present study shows how it is possible to set energy targets based on entransy and achieve them with a network of heat exchangers by an example of heat exchanger network design for four streams. In order to verify the correctness of the heat exchanger networks design method based on entransy theory, the synthesis of the HEN for the diesel hydrogenation unit is studied. Using the heat exchange networks design method based on entransy theory, the HEN obtained is consistent with energy targets. The entransy transfer efficiency of HEN based on entransy theory is 92.29%, higher than the entransy transfer efficiency of the maximum heat recovery network based on pinch technology.

Effect of Propanoic Acid on Ethanol Fermentation by Saccharomyces cerevisiae in an Ethanol-Methane Coupled Fermentation Process

Propanoic acid accumulated in an ethanol-methane coupled fermentation process affects the ethanol fermentation by Saccharomyces cerevisiae. The effects of propanoic acid on ethanol production were examined in cassava mash under different pH conditions. Final ethanol concentrations increased when undissociated propanoic acid was <30.0 mmol·L-1 . Propanoic acid, however, stimulated ethanol production, as much as 7.6% under proper conditions, but ethanol fermentation was completely inhibited when undissociated acid was >53.2 mmol·L-1 . Therefore, the potential inhibitory effect of propanoic acid on ethanol fermentation may be avoided by controlling the undissociated acid concentrations through elevated medium pH. Biomass and glycerol production decreased with propanoic acid in the medium, partly contributing to increased ethanol concentration.

Emerging function of mTORC2 as a core regulator in glioblastoma: metabolic reprogramming and drug resistance

Glioblastoma （GBM） is one of the most lethal human cancers. Genomic analyses define the molecular architecture of GBM and highlight a central function for mechanistic target of rapamycin （roTOR） signaling, roTOR kinase exists in two multi- protein complexes, namely, mTORC 1 and mTORC2. These complexes differ in terms of function, regulation and rapamycin sensitivity, mTORC 1 is well established as a cancer drug target, whereas the functions of mTORC2 in cancer, including GBM, remains poorly understood. This study reviews the recent findings that demonstrate a central function ofmTORC2 in regulating tumor growth, metabolic reprogramming, and targeted therapy resistance in GBM, which makes mTORCZ as a critical GBM drug target.

Weathering and soils formation on different parent materials in Golestan Province,Northern Iran

Geochemical, mineralogical, and micromorphologieal characteristics of soils and their relevant parent rocks including loess, ignimbrite, sandstone and limestone were investigated to identify the soil-parent material uniformity and the weathering degree of soils in Golestan Province, northern Iran. Highly developed Caleixerolls and moderately developed Haploxerepts were formed on loess and limestone, respectively. In contrast, the soils formed on ignimbrite and sandstone were non- developed Entisols. Illite was the dominant clay mineral found in ignimbrite and sandstone in both the A horizon and parent material. In loess derived soils however, smectite was dominant especially in the Bt horizon compared to its parent material indicating partly to its pedogenic formation. In limestone, illite and vermiculite were dominant both in the A and C horizons. Ti/Zr ratio proved that the studied soils were closely related to their underlying parent materials geochemically. Chemical index of alteration （CIA）, micromorphological index of soil development （MISECA）, smectite/illite＋chlorite ratio and magnetic susceptibility were applied to investigate the degree of soil development. Results showed that the most and the least developed soils were those formed on loess deposits and limestone,respectively. Application of the different geochemical and pedogenetic approaches was proved to be useful in identifying the relevance of soils to their underlying parent materials and also their degree of development.

Elementary Flux Mode Analysis for Optimized Ethanol Yield in Anaerobic Fermentation of Glucose with Saccharomyces cerevisiae

Elementary flux mode （EFM） analysis was used in the metabolic analysis of central carbon metabolism in Saccharomyces cerevisiae based on constructed cellular network. Calculated from the metabolic model, the ethanol-producing pathway No. 37 furthest converts the substrate into ethanol among the 78 elementary flux modes. The in silico metabolic phenotypes predicted based on this analysis fit well with the fermentation performance of the engineered strains, KAM3 and KAMll, which confirmed that EFM analysis is valid to direct the construction of Saccharomyces cerevisiae engineered strains, to increase the ethanol yield.

The Emotional Approach of Foreign Vowel Acquisition Within the Example of British English Vowels

The aim of the article is to present results of research that was performed with 97 Polish students of the second and third year of English Philology. The purpose of the research is to examine how conscious manipulation of facial expressions aids acquisition of foreign vowels by learners, regardless of their native language and the culture they have been brought up in. Taking advantage of achievements derived from such disciplines as psychology of emotions and phonetics depicted as a physical process, an attempt is made to find a tool that improves teaching/learning of foreign vowels, that is to say, an effort is put in search of a useful method to make the phonetic process faster and more accurate. Teachers of English are encouraged to put the method, which is described in detail in the paper, into practice with their own mother languages and to share opinions about the method with colleagues. Similarly, it is believed that it can be applied to courses of other languages than just English. Teachers of those languages are encouraged to try to use it, too.

Molt and reproduction enhancement together with hemolymph ecdysteroid elevation under eyestalk ablation in the female fiddler crab,Uca triangularis(Brachyura:Decapoda)

We present the results of eyestalk extirpation experiments performed on the fiddler crab, Uca triangularis at seasons of molting and reproduction, with a view to have a better understanding of the regulatory mechanisms of these two highly energy-demanding processes. Bilateral eyestalk ablation resulted in precocious acceleration of both molting and reproduction, irrespective of the season at which each experiment was conducted. The rate of accelerated ovarian growth, however, was maximum if the eyestalk ablation was conducted during August-January, the breeding season in the wild, or in February- May （molting-reproductive season）, wherein a section of the wild population would be engaged in molting and another section in breeding. The highest degree of precocious molt acceleration, on the other hand, was obtained during June-July when the population was primarily engaged in molting, but with no reproductive activity. The precocious oocyte maturation （due to de-eyestalking） was minimal in June--July. Significantly, the eyestalk ablation also resulted in a dramatic increase in the hemolymph ecdysteroid titer, revealing that a high ecdysteroid titer would have no restraining influence on vitellogenesis. No spawning was, however, observed among de-eyestalked females, even though their final oocyte size surpassed the size of the normal mature oocytes, implying that spawning is not exclusively under the control of eyestalk hormones. A comparative study performed on the viteUine components of the experimentals and the controls revealed that the precociously incorporated yolk under eyestalk ablation was biochemically impoverished. These results indicate that throughout the annual cycle, both the somatic and the reproductive growth of U. triangularis are under the influence of inhibitory principles from the eyestalks. It is also revealing that mere deprival of the inhibitory principles does not culminate into successful vitellogenesis. Arguably, the inhibitory influence from the eyestalks could be a prerequisite for normal healthy maturation of the oocytes and spawning.

Comprehensive utilization of kaolin ore accompanying muscovite

In light of the problems of low-quality and low degree of comprehensive utilization of Guangdong muscovite-type kaolin, the reasons affecting the quality of kaolin were found to be a small amount of maroon powdery goethite adhering to the surface of kaolin and minor muscovite affecting the firing whiteness of products. The ores were dealt with by using the new combined process of attritioning-classifieation-bleaching and flotation. The separation of kaolin from muscovite, quartz and feldspar can come true through the new process. The high-quality kaolin with the firing whiteness of 91% can be obtained, and the muscovite is comprehensively recovered by adopting the key technology of flotation. The content of high-purity muscovite produced is over 99%. The muscovite discarded by original process can be comprehensively recovered.

Corncobs as Substrate for Oleaginous Yeast-Pretreatment via Steam Explosion and Hydrolysis

Corn cobs are a promising lignocellulosic substrate for the production of biofuels like bioethanol via conventional yeast or biodiesel via oleaginous yeast. Pretreatment of the substrate is essential for further hydrolysis and fermentation steps. This study focused on the steam explosion method as pretreatment. Therefore, different steam explosion severities were evaluated. The content of glucan, xylan and Klason lignin was examined. Xylan degraded with increasing severity from 412.7 g·kg-1 （untreated） to a minimum of 127.3 g-kg1 dry matter （190 ℃/30 min）. Glucan concentrations increased from 315.1 g·kg1 （untreated） to a maximum of 371.6 g·kg-1 dry matter （200 ℃/20 min）. For soluble lignin, an increase could be observed at rising severity, from 145.3 g·kg-l （untreated） to a maximum of 214.9 g·kg-1 dry matter （190 ℃/30 min）. Furthermore, the mass recovery was calculated. At harsher pretreatment conditions, a significant mass loss was observed, estimated by the ash content in the recovered dry matter. The lowest recovery rate was observed for SF = 4.13 （190 ℃/30 min） with 68.39%. The produced inhibitors were evaluated.

220kV母线倒闸过程隐患分析及改进建议

随着当今电力行业的不断发展,220 kV母线也得到了广泛应用。而在220 kV母线的倒闸过程中,母联断路器、隔离刀闸、辅助触点等都属于危险点,一旦操作出现问题,便会预留诸多的安全隐患。基于此,对220 kV母线倒闸过程中的隐患进行分析,并针对这些隐患提出了相应的改进建议,避免误操作情况所导致的不利影响。

Ethanol Production by Enzymatic Hydrolysis of Elephant Grass

The aim of this work is to evaluate the efficiency of ethanol production by fermentation of a hydrolysate obtained by the enzymatic hydrolysis of purple elephant grass （Pennisetum purpureum Schum.） using a blend of cellulases. Three hundred grams of 20-mesh granulated purple elephant grass was subjected to hot water pretreatment at 100 ℃ for a period of 25 min in a batch autoclave reactor. The pulp obtained from the pretreatment process was washed with water at 60 ℃ and submitted to enzymatic hydrolysis using a combination of exoglucanases, endoglucanases and beta-glucosidases or β-glucosidases from Novozymes. The pH of the system was kept constant at 4.8 by adjusting the levels of acetic acid or sodium acetate in the buffer solution. Enzymatic hydrolysis occurred at 50 ℃ upon agitation at 200 rpm on a shaker for 72 hours. The hydrolysate obtained after agitation was fermented using dried Saccharomyces cerevisiae yeast （manufactured by Dr. Oetker） at 30 ℃ for 10 hours. The liquids obtained after fermentation were analysed using HPLC to determine the quantity of ethanol produced. After 4 hours of fermentation, the maximum quantity of ethanol was 1.8 g/L. The stoichiometric yield of ethanol was approximately 95%. However, the step ofpretreatment was deemed unsatisfactory due to the loss of glucose during the pretreatment process.

Finding Dirac Spin Effect in NUT Spacetime

In the present study, we are interested in finding the spin precession of a Dirac particle in expanding and rotating NUT spaeetime. A tetrad with two functions to be determined is applied to the field equation of the teleparallel theory of gravity via a coordinate transformation. The vector, the axial-vector and the tensor parts of the torsion tensor are obtained. We found that the vector parts are in the radial and Ф-directions. The axial-vector torsion is along r-direction while its other components along θ and oh-directions vanish everywhere. The vector connected with Dirac spin has been evaluated as well.

Studies on the physiological function of spermine in the process of progesterone induced toad oocyte maturation

Spermidine or spermine but not putrescine inhibited progesterone induced Bufo bufo gargarizans oocyte maturation. The ID50 for spermine inhibition via intra - oocyte mi-croinjection on maturation induced by progesterone was 6. 8 mM(100 nl). Spermine could inhibit MPF induced toad oocyte maturation with a much higher ID50.A 55 kD protein was dephosphorylated during the process of progesterone induced oocyte maturation. Spermine selectively promoted the level of phosphorylation of ?this protein in both progesterone - stimulated and hormone - untreated oocytes. The extent of its dephosphorylation was fairly correlated with the percentage of GVBD in the hormone stimulated oocytes.The level of endogenous spermine was reduced by 28% between the period of 0. 40 GVBD50 and 0. 60 GVBD50, at which 55 kD protein was dephosphorylated.Spermine inhibited progesterone - stimulated protein synthesis in almost the same dose dependent manner as its inhibitory effect on the hormone - induced maturation. The endogenous spermine regulated 55 kD protein dephosphorylation which may trigger the increase of protein synthesis and in turn promote the activation of MPF. It is possible that 55 kD protein may be one of the components of messenger ribonucleoprotein (mRNP) particles.

On L2 English Learners’Formulaic Language Use and Spoken English Fluency

This study explored the distribution of three types of English formulaic language, which involves four categories in L1 Chinese L2 English learners’ speaking performance. In addition, it investigated the relationship between the English learners’ use of formulaic language and their spoken English fluency. A CCA(canonical correlation analysis) was conducted to examine the correlations between two sets of fluency variables(dependent variables) and linguistic variables of English formulaic language use(independent variables). The fluency variable set consists of:(1)temporal indices such as SR(speech rate), AR(articulation rate), MLR(mean length of run), and PTR(phonation time ratio);(2) linguistic variables of English formulaic language like F2 R(twoword formulaic sequences/run ratio, B3 R(three-word lexical bundles/run ratio), and B4 R(fourword lexical bundles/run ratio). These are calculated according to the frequency of the English formulaic language in the speech samples of the participants(n = 86) across three academic levels.The results indicate that the learners’ spoken English fluency is highly related to their use of English formulaic language. Its limitations and future research directions are also discussed.

Process Control and Optimization for Heterologous Protein Production by Methylotrophic Pichia pastoris

The methylotrophic yeast Pichia pastoris is a highly successful system for production of a variety of heterologous proteins due to its unique features/abilities for effective protein expression, and tremendous efforts have been made to increase heterologous protein productivity by P. pastoris in recent years. When new engineered yeast strains are constructed and are ready to use tot industrial protein production, process control and optimization techniques should be applied to improve the fermentation performance in the following aspects： （1） increase recombinant cell concentrations in fermentor to high density during growth phase; （2） effectively induce heterologous proteins by enhancing/stabilizing titers or concentrations of the proteins during induction phase; （3） decrease operation costs by relieving the working loads of heat-exchange and oxygen supply. This article reviews and discusses the key and commonly used techniques in heterologous protein production by P. pastoris, with the focus on optimizations of fermentation media and basic operation conditions, development of optimal glycerol feeding strategies for achieving high density cultivation of P. pastoris and effective heterologous protein induction methods by regulating specific growth rate, methanol concentration, temperatures, mixture ratio of multi-carbon substrates, etc. Metabolic analysis for recombinant protein production by P. pastoris is also introduced to interpret the mechanism of sub-optimal heterologous protein production and to explore further optimal expression methods.

Viability of Lactobacillus acidophilus La-5 in the Presence of Williopsis saturnus vat. suaveolens

Maintaining the viability of probiotic microorganisms from production to consumption has long been a technological challenge for the food industry. The objectives of this study were to evaluate the in vitro interaction between Lactobacillus acidophilus La-5 and Williopsis saturnus var. suaveolens and the effect of this yeast on acidification kinetics, viability ofLactobacillus acidophilus and post-acidification in fermented milk during refrigerated storage at 5℃. The in vitro study showed a positive interaction between the acid cell free-supernatant （CFS） ofprobiotic bacteria La-5 and the yeast. The addition of W. saturnus var. suaveolens increased the fermentation time due to consumption of the organic acids produced by L. acidophilus. During the refrigerated storage of the samples, the presence of the yeast increased the viability of L. acidophilus and reduced post-acidification. However, the mechanism of such interaction of bacteria and yeast is not fully understood.

Protein Expression of Goat Follicular Fluid （GFF）

Oocyte maturation process is very complex. Until now synthesis and protein function as well as pathway mechanism in oocyte maturation process are not yet well understood. The mechanism of goat follicular fluid （GFF） in maturation in vitro medium needs to be deeply studied before it is implemented widely. The aim of the research was analyzing the GFF to know protein expression of ERK1, ERK 2, p90rsk, Cyclin-Bl and cdc25A by Western Blotting method. GFF collection by aspiration from small follicle （〈 4 mm） and big follicle （4-8 mm） by using needle with spuit size of 18 G. It was concluded that there was protein expression of ERK2 and p90rsk, at 42 kDa and 22 kDa respectively.

Entropy Production along Dominant Pathway of Nonequilibrium Phase Transition in Mesoscopic Chemical System

We consider a bistable mesoscopic chemical reaction system and calculate entropy produc- tion along the dominant pathway during nonequilibrium phase transition. Using probability generating function method and eikonal approximation, we first convert the chemical master equation into the classical Hamilton-Jacobi equation, and then find the dominant pathways between two steady states in the phase space by calculating zero-energy trajectories. We find that entropy productions are related to the actions of the forward and backward dominant pathways. At the coexistence point where the stabilities of the two steady states are equiv alent, both the system entropy change and the medium entropy change are zero; whereas at non-coexistence point both of them are nonzero.

Recent advances in metabolic engineering of microorganisms for production of tyrosol and its derivatives

Tyrosol is a natural phenolic compound with antioxidant,anti-inflammatory and other biological activities,serving as an important precursor of high-value products such as hydroxytyrosol and salidroside.Therefore,the green and efficient biosynthesis of tyrosol and its derivatives has become a research hotspot in recent years.Building cell factories by metabolic engineering of microorganisms is a potential industrial production way,which has low costs and environmental friendliness.This paper introduces the biosynthesis pathway of tyrosol and presents the key regulated nodes in the de novo synthesis of tyrosol in Escherichia coli and Saccharomyces cerevisiae.In addition,this paper reviews the recent advances in metabolic engineering for the production of hydroxytyrosol and salidroside.This review can provide a reference for engineering the strains for the high-yield production of tyrosol and its derivatives.

苏轼陆路出蜀路线考探

引言苏轼一生凡三次出蜀,二次返蜀,陆路和水路都走过。嘉祐元年(1056)三月,三苏父子赴京出蜀,熙宁元年(1068)冬,苏轼兄弟服父丧满,一起还朝,这两次出蜀均走陆路。其中还有一次陆路归蜀,为嘉祐二年(1057)夏,苏轼兄弟一举成名时,母程夫人故,父子三人仓惶离京,回乡奔丧,此次陆路归蜀史料甚少,本文不做探讨。