The Orientations of Large Aspect‐Ratio Coiled‐Coil Proteins Attached to Gold Nanostructures

Methods for patterning biomolecules on a substrate at the single molecule level have been studied as a route to sensors with single‐molecular sensitivity or as a way to probe biological phenomena at the single‐molecule level. However, the arrangement and orientation of single biomolecules on substrates has been less investigated. Here, the arrangement and orientation of two rod‐like coiled‐coil proteins, cortexillin and tropomyosin, around patterned gold nanostructures is examined. The high aspect ratio of the coiled coils makes it possible to study their orientations and to pursue a strategy of protein orientation via two‐point attachment. The proteins are anchored to the surfaces using thiol groups, and the number of cysteine residues in tropomyosin is varied to test how this variation affects the structure and arrangement of the surface‐attached proteins. Molecular dynamics studies are used to interpret the observed positional distributions. Based on initial studies of protein attachment to gold post structures, two 31‐nm‐long tropomyosin molecules are aligned between the two sidewalls of a trench with a width of 68 nm. Because the approach presented in this study uses one of twenty natural amino acids, this method provides a convenient way to pattern biomolecules on substrates using standard chemistry.     

Globalization at the nano frontier: The future of nanotechnology policy in the United States, China, and India

The field of nanotechnology offers the possibility of transforming the international science and technology (S&T) policy landscape and making a significant impact on the direction of research and development for a wide range of nations and companies. Nanotechnology endeavors in the United States, China, and India remain some of the most interesting because of the opportunities and challenges this field poses for future competition and collaboration between these three nations. This paper examines how nanotechnology will raise new science and policy questions—and lead to new strategic linkages—that will have a major impact on the futures of these nations for decades to come. Then the paper analyzes and compares the current state of nanotechnology in these three countries, discusses some of the main drivers of collaboration, investigates current and potential uncertainties associated with nanotechnology, and offers policy suggestions on ways that these difficulties may be addressed.     

The back-buffer algorithm: An extension of the radiosity method to dynamic environments

An efficient algorithm is introduced for the production of realistic image sequences of dynamic environments. The practicality of the radiosity method, which computes the interreflection of light within complex diffuse environments independent of viewpoint, is extended to dynamic environments where the paths of moving objects have been predefined. The algorithm takes advantage of the object coherence between static portions of an environment. A preprocessing stage executes once for a given image sequence and precalculates constant geometrical relationships in the environment. When the environment geometry changes, an update stage determines the global illumination using information provided by the preprocessor and the current positions of all moving objects. Test environments show speedups of at least twenty-five times over previous radiosity methods.     

Differential effects of experiential and problem-solving interventions in resolving marital conflict.

Compared the relative effectiveness of 2 interventions in the treatment of marital discord: a cognitive-behavioral intervention that focused on teaching problem-solving skills and an experiential intervention that focused on emotional experiences underlying interaction patterns. 45 couples seeking therapy were randomly assigned to 1 of these treatments or to a wait-list control group. Each treatment was administered in 8 sessions by 6 experienced therapists whose interventions were monitored and rated to ensure treatment fidelity. Assessment measures included the Dyadic Adjustment Scale; Couples Therapy Alliance Scale; and tests of emotional style, target complaints, goal attainment, and intimacy. Results indicate that the perceived strength of the working alliance between couples and therapists and of general therapists effectiveness were equivalent across treatment groups and that both treatment groups made significant gains over untreated controls on measures of goal attainment, marital adjustment, intimacy levels, and target complaint reduction. The effects of the emotionally focused treatment were superior to those of the problem-solving treatment on marital adjustment, intimacy, and target complaint level. At follow-up, marital adjustment scores in the emotionally focused group were still significantly higher than those in the problem-solving group. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dbxtool: A window-based symbolic debugger for sun workstations

Dbxtool is a window- and mouse-based debugger for C, Pascal and FORTRAN programs running on Sun workstations. Its use of the mouse as the primary input mechanism eliminates the need to type variables, line numbers, breakpoints and most commands. Its multiple windows provide several qualitatively different perspectives on the debugging problem. Compared to the Unix 4.2 BSD dbx from which it is derived, it has been extended with the abilities to debug multiple-process programs, already-running processes, and the Sun Operating System kernel.     

Further evidence for the increased power of LOD scores compared with nonparametric methods

Platelet-derived growth factor (PDGF), a mitogen and chemoattractant for mesenchymal cells, occurs as cell-associated or released isoforms. To investigate their in vivo role, human keratinocytes, which normally synthesize both types of PDGF, were genetically modified to overexpress either wild-type PDGF-B (cell-associated) or the truncation mutant PDGF-B211 (released). Cells expressing the mutant isoform released 20 times more PDGF (145 ng/hour/10(7) cells) than cells expressing the wild-type isoform (6 ng/ hour/10(7) cells). When grafted as epithelial sheets onto athymic mice, modified cells formed a stratified epithelium and induced a connective tissue response that differed depending on the PDGF isoform expressed. Expression of PDGF-B211 induced a thick connective tissue with increased numbers of fibroblasts, mononuclear cells, and blood vessels evenly distributed throughout the connective tissue layer, whereas expression of PDGF-B induced a zone of fibroblasts and mononuclear cells localized to the interface of the epidermis and connective tissue, which often disrupted the continuity of the basement membrane. Immunostaining revealed that wild-type PDGF protein was deposited in the basement membrane region. These data suggest that the different binding properties of PDGF isoforms control the spatial organization of cellular events in regenerating mesenchymal tissue in vivo.     

The effect of biomass adsorption on the removal of selected pharmaceutical compounds in an immersed membrane bioreactor system

BACKGROUND: The performance of a pilot membrane bioreactor system (MBR) was tested for the treatment of municipal wastewater, with emphasis on the capability for removal of selected pharmaceuticals RESULTS: The MBR showed excellent performance with regards to conventional pollutants. However, the removal of specific pharmaceuticals was not as high. Carbamazepine and 17 α‐ethinyl estradiol showed the lowest removal, with mean removal rates of around 20%. Clofibric acid showed the highest removal 70%, while for 17β‐estradiol the mean removal was 40%. In order to distinguish between the two basic mechanisms of removal, adsorption on biomass and biodegradation, adsorption studies on inactivated biomass were performed and mass balances were written for the four pharmaceuticals. The immediate removal observed for the three compounds during short hydraulic retention times may have been primarily due to adsorption. CONCLUSIONS: The removal of carbamazepine, 17β‐estradiol and 17α‐ethynil estradiol, as well as half of the removal of chlofibric acid could be attributed to direct adsorption on biomass within the hydraulic residence time of the reactor. Copyright © 2011 Society of Chemical Industry     

Cloning and expression of a jellyfish calcium channel beta subunit reveal functional conservation of the alpha1-beta interaction.

In high voltage-activated calcium channels, the binding between the pore-forming alpha1 subunit and the modulatory beta subunit is mediated by interaction domains in each molecule that are highly conserved among most known subunits. However, the interaction domain within CyCaalpha1, an alpha1 subunit cloned from the jellyfish Cyanea capillata, matches the canonical sequence of the alpha1 interaction domain at only four of nine sites. We have now cloned a cDNA from Cyanea neuromuscular tissue that encodes a Ca2+ channel beta subunit. The subunit, named CyCabeta, shares 47-54% identity with vertebrate beta subunit isoforms, but is most highly conserved within its interaction domain. Coexpression of CyCabeta with CyCaalpha1 in Xenopus oocytes increases the amplitude of the CyCaalpha1 current and shifts its activation to more hyperpolarized potentials. These responses are mimicked by coexpression of the rat beta2a subunit, demonstrating that the alpha1 beta interaction is functionally conserved between cnidarians and mammals. CyCabeta also markedly accelerates the rate of recovery of CyCaalpha1 from inactivation, an action that is modestly duplicated by beta2a and may represent an additional mechanism by which beta subunit isoforms differentially modulate alpha1 subunits. These findings establish that limited conservation within the alpha1 interaction domain is sufficient to allow full modulation by a beta subunit, as well as altered regulation by different beta isoforms.     

Intracerebral hemorrhage after carotid endarterectomy: incidence, contribution to neurologic morbidity, and predictive factors

PURPOSE: With a diminishing rate of cardiac and neurologic events after carotid endarterectomy, intracerebral hemorrhage is gaining increasing importance as a cause of perioperative morbidity and mortality. To date, information has been largely anecdotal, and there has been no comparison with a control group of patients. METHODS: The records of all patients experiencing symptomatic intracerebral hemorrhage after carotid endarterectomy were reviewed and compared with data from 50 randomly selected patients who did not experience intracranial bleeding. Univariate analyses were performed, using the Fisher exact test for dichotomous data and the Student t test for continuous data. RESULTS: During a 6-year period, symptomatic intracranial hemorrhage developed in 11 (0.75%) of 1471 patients undergoing carotid endarterectomy, accounting for 35% of the 31 total perioperative neurologic events. Hemorrhage occurred a median of 3 days postoperatively (range, 0 to 18 days). Signs and symptoms included hypertension in all 11 patients, headache in 7 conscious patients (64%), and bradycardia in 6 patients (55%). Massive hemorrhage with herniation and death occurred in 4 patients (36%). Moderate hemorrhage developed in 5 patients (45%); 3 of these patients had partial recovery, and 2 had complete recovery. Petechial hemorrhage occurred in the remaining 2 patients (18%), 1 with partial and 1 with complete recovery. In comparison with the control group, there were no differences in respect to sex, indication for operation, smoking or diabetic history, and antiplatelet therapy or perioperative heparin management. Patients with intracranial hemorrhage were, however, younger, more frequently hypertensive, had a higher degree of ipsilateral and contralateral carotid stenosis, and had a higher rate of contralateral carotid occlusion. CONCLUSION: Intracranial hemorrhage occurs with notable frequency after carotid endarterectomy and accounts for a significant proportion of neurologic morbidity and mortality. Younger patients, hypertensive patients, and patients with severe cerebrovascular occlusive disease appear to be at greatest risk for the complication.