Interactions of the alpha-spectrin N-terminal region with beta-spectrin. Implications for the spectrin tetramerization reaction

Spectrin of the erythrocyte membrane skeleton is composed of alpha- and beta-spectrin, which associate to form heterodimers and tetramers. It has been suggested that a fractional domain (helix C) in the amino-terminal region of alpha-spectrin (Nalpha region) bundles with another fractional domain in the carboxyl-terminal region of beta-spectrin (Cbeta region) to yield a triple alpha-helical bundle and that this helical bundling is largely responsible for tetramer formation. However, there are certain objections to assigning a preeminent role to this helical bundling in the tetramerization reactions. We prepared several recombinant peptides of alpha-spectrin fragments spanning only the Nalpha region (lacking the dimer nucleation site) and quantitatively studied their interaction with beta-spectrin. We found that a majority of the interactions were localized, as expected, in the Nalpha-helix C region but that there was also some contribution from the nonhomologous region. More importantly, the temperature and ionic strength dependence of this interaction in our model peptides was different from that in intact spectrin. We suggest that, although the regions involving the putative helical bundling in alpha- and beta-spectrin undoubtedly play a significant role in tetramerization, regions distal to the Nalpha-helix C region in spectrin are also involved in tetramer formation. Structural flexibility and lateral interactions may play a role in spectrin tetramerization.     

Impact fatigue of a polycarbonate/acrylonitrile-butadiene-styrene blend

This study analyzes the impact properties of a polycarbonate/acrylanitrile-butadiene-styrene (PC/ABS) blend. The specimens were prepared under various injection molding conditions, including filling time, melting temperature, and mold temperature. Impact tests were performed with a Dynatup drop weight impact tester at different impact energies (10, 15, 20, 25 J). The fracture mechanism was examined with a scanning electron microscopy. The results indicated that the load-time history of the PC/ABS blend has approximately a sinusoidal form in impact. The best injection molding conditions are a filling time of 12 s, a melting temperature of 260°C and a mold temperature of 80°C. In this case, the specimen shows the highest energy absorbed in single impact, together with the highest impact number in impact fatigue. The impact number and the accumulation energy seem to follow an exponential curve as the impact energy decreases. The PC/ABS blend material clearly exhibited ductile fracture with a continuous reduction in strength by viscoplastic deformation. The higher the impact number, the higher the accumulation energy. The accumulation energy of impact fatigue with impact energy 10 J is about 35–45 times greater than the energy absorbed in single impact. Tearing, shear fracture, and plastic deformation are the major fracture mechanisms of the PC/ABS blend matrix in single impact and repeated impact conditions.     

Lead-acid batteries in micro-hybrid applications. Part I. Selected key parameters

Micro-hybrid electric vehicles were launched by BMW in March 2007. These are equipped with brake energy regeneration (BER) and the automatic start and stop function (ASSF) of the internal combustion engine. These functions are based on common 14 V series components and lead-acid (LA) batteries. The novelty is given by the intelligent onboard energy management, which upgrades the conventional electric system to the micro-hybrid power system (MHPS). In part I of this publication the key factors for the operation of LA batteries in the MHPS are discussed. Especially for BER one is high dynamic charge acceptance (DCA) for effective boost charging. Vehicle rest time is identified as a particular negative parameter for DCA. It can be refreshed by regular fully charging at elevated charge voltage. Thus, the batteries have to be outstandingly robust against overcharge and water loss. This can be accomplished for valve-regulated lead-acid (VRLA) batteries at least if they are mounted in the trunk. ASSF goes along with frequent high-rate loads for warm cranking. The internal resistance determines the drop of the power net voltage during cranking and is preferably low for reasons of power net stability even after years of operation. Investigations have to be done with aged 90 Ah VRLA-absorbent glass mat (AGM) batteries. Battery operation at partial state-of-charge gives a higher risk of deep discharging (overdischarging). Subsequent re-charging then is likely to lead to the formation of micro-short circuits in the absorbent glass mat separator.     

Age differences in the likelihood of destructive anger responses under different relationship contexts: A comparison of mainland and Hong Kong Chinese.

This brief report examined how the likelihood of destructive anger responses varied with age across relationship contexts. Seventy-six older adults and 100 younger adults from Hong Kong and Mainland China reported their responses to anger-eliciting scenarios elicited by a kin, a close or a casual friend. Results indicated that compared with their younger counterparts, older Hong Kong Chinese were less likely to report direct aggression toward kin, but older Mainland Chinese were more likely to do so. Older Hong Kong Chinese were less likely to report malevolent and fractious motives than were younger Chinese across all relationships; Older Mainland Chinese were less likely to do so only in friendship. Findings have implications for conceptualizing age-related emotion regulation across relationships and cultures. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Economic limit of field production in Texas

When the revenue generated from an oil and gas field is less than the cost of operations, the field is no longer considered an asset and production ceases. Capital investment may be made in an attempt to increase production or the field may be divested or abandoned. At some point in time all fields will terminate production at their economic limit. The purpose of this paper is to quantify the economic limit of field production in Texas. We classify 16,045 fields that terminated production between 1993 and 2008 by product type, location, and year of termination, and compute average production and adjusted gross revenue statistics near the end of the field’s life cycle. We demonstrate that the revenue thresholds of offshore oil and gas fields is greater than the economic limits of fields located in bays-estuaries and on land and gas fields turn marginal sooner than oil fields. During the last year of production, average oil field revenue varied from $65,000 on land and bays-estuaries to $181,000 offshore; gas field revenue thresholds ranged from $384,000 (land) to $584,000 (bays-estuaries) to $637,000 (offshore).     

Geno2pheno: interpreting genotypic HIV drug resistance tests

This intelligent system uses information encoded in the HIV genomic sequence to predict the virus's resistance or susceptibility to drugs. To make predictions, geno2pheno employs decision tree classifiers and support vector machines.     

Numerical study of multiplanar tubular DX-joints subject to axial loads

In this paper, 20 multiplanar DX-joints (double X) with in-plane braces and out-of-plane braces subjected to various combination of axial loads were analysed. The multiplanar effect of loaded and unloaded out-of-plane braces and the load-interaction of multiplanar DX-joints were investigated. The influence of geometric parameters on the stress concentration factors of the joints was also studied. The results obtained from the analyses of multiplanar DX-joints are compared with those of the corresponding uniplanar X-joints. It is found that, when the out-of-plane braces are not loaded, the multiplanar effect is not significant when the brace diameter is much smaller than the chord diameter. When the out-of-plane braces are loaded, the hot spot stresses are found to be lower or higher than the values predicted based on uniplanar joints. The deviation can be as much as 87% or 94%, respectively, depending on the combination of the load conditions and geometrical parameters.     

SWAP: leveraging the Web to manage workflow

Many organizations are beginning to discover what workflow vendors already know-namely, that the real value of the Web lies not just in its documents and resources, but also in the activities surrounding them. Collaborative work involves not only handoff and routing of data between humans, but the coordination of activities among them and with automated agents as well. Workflow engines typically ensure that the information ends up on the right desktop along with the tools to accomplish a slated task. It is difficult to synchronize work and activity tracking within a technically diverse organization. Tools and formats typically differ among workgroups, as do skill levels and understanding among individual participants in a process. Browser-based user interfaces offer a mechanism to easily access distributed information and hand off documents and data over the Web, but at the expense of being able to effectively manage and track work activities. Web protocols provide no inherent support for automated change notification, handoff of control, or initiation of human- and computer-executed activities. In essence, there is no standard way for service requests to trigger a workflow process and monitor it across platforms and between organizations     

Sending memorable messages to the old: Age differences in preferences and memory for advertisements.

Socioemotional selectivity theory holds that people of different ages prioritize different types of goals. As people age and increasingly perceive time as finite, they attach greater importance to goals that are emotionally meaningful. Because the goals that people pursue so centrally influence cognition, the authors hypothesize that persuasive messages, specifically advertisements, would be preferred and better remembered by older adults when they promise to help realize emotionally meaningful goals, whereas younger adults would not show this bias. The authors also predict that modifying time perspective would reduce age differences. Findings provide qualified support for each of these predictions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Complete spontaneous remission in a patient with metastatic non-small-cell lung cancer. Case report, review of the literature, and discussion of possible biological pathways involved

Spontaneous remission of cancer (SR) is defined as a complete or partial, temporary or permanent disappearance of all or at least some relevant parameters of a soundly diagnosed malignant disease without any medical treatment or with treatment that is considered inadequate to produce the resulting regression. We report the case of a 61-year-old man who presented with extensive metatastic disease five months after pneumonectomy for poorly differentiated large cell and polymorphic lung cancer. A vast metastatic tumour mass of the abdominal wall was confirmed histolologically and there was clinical and radiographic evidence of liver and lung metastases. Eight months later, the patient was operated on for a hernia, which had developed in the inguinal biopsy scar and the surgeon confirmed complete clinical SR of the abdominal wall metastases. Again five months later there was no longer any radiologic evidence of liver and lung metastases. Complete remission has persisted more than five years. Histology of the primary and of the abdominal metastases were reviewed by several independent pathologists. SR is an extremly rare event in lung cancer. This is the first documented case of clinically evident visceral metastases of a bronchiogenic adenocarcinoma developing after complete resection of the primary and then showing complete SR. The epidemiology of SR is reviewed and possible mechanisms involved in SR are discussed.