Lithium Chloride as a Preferred Extractant of Fish Muscle Proteins

Lithium chloride yielded better extraction of fish muscle protein than sodium or potassium chloride under most conditions. In addition, constancy of extracted protein was better with lithium compared to potassium or sodium chlorides with respect to blending time, salt concentration, pH, temperature and foaming. With stored red hake muscle, LiCl was superior to NaCl with better extractability of protein and more linear reduction of extractability with storage time. Evidence indicated the superior performance of lithium compared to sodium was due to stabilization by lithium chloride of fish proteins towards denaturation.     

EFFECT OF VARIOUS ANTIOXIDANTS ON THE OXIDATIVE STABILITY OF ACID AND ALKALI SOLUBILIZED MUSCLE PROTEIN ISOLATES

Protein isolates prepared from cod ( Gadus morhua ) myofibrillar proteins using acid or alkali solubilization are susceptible to oxidative rancidity. Oxidation could be delayed by the exogenous addition of antioxidants. The objective of this research was to compare the efficacy of antioxidants such as δ-tocopherol, butylated hydroxyanisole (BHA) and propyl gallate, to inhibit oxidation in acid- and alkali- solubilized cod protein isolates. Oxidation was catalyzed using cod hemolysate. Oxidation of lipids was monitored by the measurement of thiobarbituric acid reactive substances and painty odor. Results showed that protein isolates prepared using the acid process was significantly ( P <  0.05) more susceptible to lipid oxidation than alkali-solubilized protein isolates. Regardless of pH treatments, the efficacy of various antioxidants decreased in the order propyl gallate  >  BHA  >  δ-tocopherol.

PRACTICAL APPLICATIONS

Research has shown that seafood available for human consumption is rapidly getting depleted and that many fish species may become extinct in the next half-century or so. Acid and alkali solubilization methods are recent but well-known techniques used for preparing protein isolates from under-utilized aquatic species and the by-products of seafood industry. Although numerous researchers have studied the use of acid and alkali processes on several sources of seafood, almost no research has been done on the use of antioxidants to protect protein isolates from lipid oxidation. In our research, we have studied the effect of various antioxidants on the oxidative stability of acid- and alkali-solubilized fish myofibrillar proteins. The results from this work will enable the seafood industry to properly identify the process and the type of antioxidants required for making muscle food products with increased oxidative stability.     

Effects of Packaging Method, Display Light and Storage Time On The Microbial Growth and Rancidity of Fresh Pork

Effects of display light, packaging methods and storage time on total aerobic, lipolytic and proteolytic counts and oxidative rancidity of fresh pork stored at 2 ± 1° C were studied at the initial, 7th, 14th and 21st day of storage. Display light significantly increased the total aerobic psychrotroph count. Effects on lipolytic and proteolytic psychiotroph counts were not significant. No anaerobic psychrotrophs were encountered. Total and proteolytic counts of PVC film overwrapped chops and proteolytic and lipolytic psychrotroph counts of chops vacuum packaged accelerated linearly with time. Increases in lipolytic psychrotroph count of PVC packaged and total aerobic psychrotroph count of vacuum packaged chops were quadratic. TBA number and rancid odor scores were not significantly affected by treatments.     

CROSS-CULTURAL STUDY OF THE THWARTING-DISORIENTATION THEORY OF SUICIDE.

A CROSS-CULTURAL SURVEY OF 58 CULTURES INVESTIGATED THE THWARTING-DISORIENTATION THEORY OF SUICIDE. HYPOTHESIZED THAT SUICIDE TAKES PLACE IN CONTEXTS IN WHICH A PERSON'S SOCIAL TIES ARE DISRUPTED OR THREATENED WITH DISRUPTION BY THE DISCRETIONARY ACTS OF HIMSELF OR SOMEONE ELSE. ALSO, IT WAS POSITED THAT THE MORE OPPORTUNITIES THAT A SOCIETY PROVIDES FOR THE OCCURRENCE OF THWARTING DISORIENTATION, THE GREATER WOULD BE ITS SUICIDE RATE. EVIDENCE CONFIRMING THESE HYPOTHESES WAS OBTAINED. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Comparison of Dogfish and Bovine Chymotrypsins in Relation to Protein Hydrolysis

An extracellular protease, chymotrypsin, from a low temperature-adapted poikilotherm (dogfish) was compared with the bovine enzyme against several protein substrates to determine potential advantages in the use of an enzyme adapted to functioning in a low temperature environment. In general, the dogfish enzyme showed a higher rate of reaction and hydrolyzed more peptide bonds than did the bovine enzyme whether the substrates were soluble or insoluble proteins. Dogfish chymotrypsin was slow to produce clotting of milk, but once formed the clot had good stability. The bovine enzyme was more efficient in incorporating methionine into soy protein in a piasteintype reaction.     

An initial evaluation of the detection and diagnosis of power plant faults using a deep knowledge representation of physical behaviour

Abstract: This paper describes an initial evaluation of a deep knowledge representation technique called Incremental Qualitative Analysis (IQA) to assess whether it is reasonably able to discriminate between different behaviours and hence different faults on a power plant. As an example the detection and diagnosis of faults in a PWR pressuriser sub-system have been implemented in Prolog and evaluated using transients from a reference computer model of a pressuriser in conjunction with an input processor. The application differs from earlier systems for diagnosing faults in electronic hardware in that it is necessary to represent external feedback, two-way components and sensor failures. The diagnosis is by synthesis and uses 'constraint satisfaction and suspension' techniques. For the present implementation all imposed faults have been successfully detected and diagnosed with reasonable determinacy, and a spurious detection has never occurred. IQA appears to be a suitable basis for knowledge-based operator aids although to produce a real-time aid appears to require more sophisticated techniques for fault detection and diagnosis, such as 'constraint propagation' and 'candidate generation". These techniques also offer the prospect of providing pseudo-causal explanations to justify their hypotheses.     

汽车风挡玻璃用密封胶的结构与性能研究

研究了三种汽车风挡玻璃用单组分PU(聚氨酯)密封胶和SPU(硅烷改性聚氨酯)密封胶。采用红外光谱(FT-IR)、凝胶渗透色谱(GPC)法分析了三种密封胶的结构和相对分子质量,并对其固化行为、粘接性能和力学性能等进行了研究。结果表明:相对湿度越大(或固化温度越高),则三种密封胶的表干时间越短且固化速率越大;在三种密封胶的储存过程中,其表干时间和固化速率变化不大,稳定性较好;SPU密封胶与基材的粘接性能优于PU密封胶;PU密封胶的拉伸强度(≥8.2 MPa)和撕裂强度(19 N/mm)均优于SPU密封胶的拉伸强度(5.8 MPa)和撕裂强度(13 N/mm)。