Durable and scalable icephobic surfaces: similarities and distinctions from superhydrophobic surfaces.

Formation, adhesion, and accumulation of ice, snow, frost, glaze, rime, or their mixtures can cause severe problems for solar panels, wind turbines, aircrafts, heat pumps, power lines, telecommunication equipment, and submarines. These problems can decrease efficiency in power generation, increase energy consumption, result in mechanical and/or electrical failure, and generate safety hazards. To address these issues, the fundamentals of interfaces between liquids and surfaces at low temperatures have been extensively studied. This has lead to development of so called "icephobic" surfaces, which possess a number of overlapping, yet distinctive, characteristics from superhydrophobic surfaces. Less attention has been given to distinguishing differences between formation and adhesion of ice, snow, glaze, rime, and frost or to developing a clear definition for icephobic, or more correctly pagophobic, surfaces. In this review, we strive to clarify these differences and distinctions, while providing a comprehensive definition of icephobicity. We classify different canonical families of icephobic (pagophobic) surfaces providing a review of those with potential for scalable and robust development.

GOModeler--a tool for hypothesis-testing of functional genomics datasets.

BACKGROUND: Functional genomics technologies that measure genome expression at a global scale are accelerating biological knowledge discovery. Generating these high throughput datasets is relatively easy compared to the downstream functional modelling necessary for elucidating the molecular mechanisms that govern the biology under investigation. A number of publicly available 'discovery-based' computational tools use the computationally amenable Gene Ontology (GO) for hypothesis generation. However, there are few tools that support hypothesis-based testing using the GO and none that support testing with user defined hypothesis terms.Here, we present GOModeler, a tool that enables researchers to conduct hypothesis-based testing of high throughput datasets using the GO. GOModeler summarizes the overall effect of a user defined gene/protein differential expression dataset on specific GO hypothesis terms selected by the user to describe a biological experiment. The design of the tool allows the user to complement the functional information in the GO with his/her domain specific expertise for comprehensive hypothesis testing. RESULTS: GOModeler tests the relevance of the hypothesis terms chosen by the user for the input gene dataset by providing the individual effects of the genes on the hypothesis terms and the overall effect of the entire dataset on each of the hypothesis terms. It matches the GO identifiers (ids) of the genes with the GO ids of the hypothesis terms and parses the names of those ids that match to assign effects. We demonstrate the capabilities of GOModeler with a dataset of nine differentially expressed cytokine genes and compare the results to those obtained through manual analysis of the dataset by an immunologist. The direction of overall effects on all hypothesis terms except one was consistent with the results obtained by manual analysis. The tool's editing capability enables the user to augment the information extracted. GOModeler is available as a part of the AgBase tool suite (http://www.agbase.msstate.edu). CONCLUSIONS: GOModeler allows hypothesis driven analysis of high throughput datasets using the GO. Using this tool, researchers can quickly evaluate the overall effect of quantitative expression changes of gene set on specific biological processes of interest. The results are provided in both tabular and graphical formats.

Elastic turbulence in shear banding wormlike micelles.

We study the dynamics of the Taylor-Couette flow of shear banding wormlike micelles. We focus on the high shear rate branch of the flow curve and show that for sufficiently high Weissenberg numbers, this branch becomes unstable. This instability is strongly subcritical and is associated with a shear stress jump. We find that this increase of the flow resistance is related to the nucleation of turbulence. The flow pattern shows similarities with the elastic turbulence, so far only observed for polymer solutions. The unstable character of this branch led us to propose a scenario that could account for the recent observations of Taylor-like vortices during the shear banding flow of wormlike micelles.

Peptide T in the treatment of painful distal neuropathy associated with AIDS: results of a placebo-controlled trial. The Peptide T Neuropathy Study Group.

OBJECTIVE: To assess the safety and efficacy of Peptide T in the treatment of painful distal symmetrical polyneuropathy (DSP) associated with human immunodeficiency virus (HIV) infection. BACKGROUND: Painful DSP is a frequent complication of HIV infection, although its etiology and optimal treatment are unknown. Peptide T (D-(alpha 1)-Peptide T-amide) has been found in phase I trials and anecdotal reports to relieve neuropathic pain in AIDS patients. DESIGN/METHODS: In this multicentered, double-blind, randomized study, subjects received intranasal Peptide T 6 mg/day or placebo for 12 weeks. The primary outcome measure was change in the modified Gracely pain score. Secondary efficacy variables were results of neurologic examination, neuropsychological and electrophysiologic studies, global evaluation, and CD4 lymphocyte counts. RESULTS: Of 81 evaluable subjects, 40 received Peptide T and 41 received placebo. The change in pain scores was not significantly different (p = 0.32) in the Peptide T group (-0.24) as compared to placebo (-0.39). Group comparisons were not significantly different for change in any clinical examination or neuropsychologic measure, sural nerve amplitude or conduction velocity, or CD4 lymphocyte count. No significant drug-related adverse effects occurred in either group. CONCLUSION: Intranasal Peptide T is safe but ineffective in the treatment of painful DSP associated with AIDS.

Improvement of Herpesvirus saimiri T cell immortalization procedure to generate multiple CD4+ T-cell clones from peripheral blood lymphocytes of AIDS patients.

Herpesvirus saimiri (HVS) can infect and immortalize human T lymphocytes of both CD4- and CD8-positive phenotypes. We have previously shown that infection of peripheral blood lymphocytes (PBL) from AIDS patients with HVS predominantly yielded immortalized CD8-positive T cell clones. Here we show that CD4-positive T cells from AIDS patients can be efficiently immortalized by HVS if patient PBL are enriched for CD4-positive T cell subpopulation prior to HVS infection. Such cells can be cloned and maintained in culture for prolonged times, and they exhibit activated T cell phenotype of Th1 class and are susceptible to HIV-1 infection. Several immortalized T cell clones obtained from one out of three AIDS patients tested here were HIV-1 positive and produced infectious virus. This approach permits efficient generation of multiple CD4-positive T cell clones from AIDS patients for functional and virological studies.

Modulation of cellular gene expression of HIV type 1 infection as determined by subtractive hybridization cloning: downregulation of thymosin beta 4 in vitro and in vivo.

Chronic infection with HIV-1 has profound effects on host cell growth and function. We used subtractive hybridization cloning to identify genes whose expression is modulated by HIV-1 infection in the T leukemia cell line CEM. The gene encoding thymosin beta 4, a ubiquitous polypeptide associated with hematopoietic differentiation, showed two- to threefold reduced transcription in HIV-1-infected CEM cells and other HIV-1-infected T cells and macrophages in vitro. Solid-phase radioimmunoassay revealed about a threefold decrease in the level of thymosin beta 4 protein in lysates of infected cells. Northern blot analysis of RNA samples from lymphocytes of five AIDS patients reveals an up to fivefold reduction in the level of thymosin beta 4 mRNA. These results indicate that HIV-1 infection may directly influence the expression of certain physiologically important proteins.

Treatment of acyclovir-unresponsive cutaneous herpes simplex virus infection with topically applied SP-303.

The naturally occurring polyphenolic biopolymer SP-303 has in vitro activity against both HSV-1 and HSV-2, including strains that are resistant to acyclovir. Nine AIDS patients with acyclovir-unresponsive mucocutaneous herpes simplex virus infection were treated with thrice daily topical SP-303T ointment in an open-label pilot study. Although a transient decrease in lesion size was observed in 4 patients during study drug therapy, and 3 patients sustained a quantitative decrease in virus burden, neither complete healing nor cessation of virus shedding occurred in any patient. Seven patients complained of pain or burning upon application of the study ointment, causing 1 patient to terminate the study. In summary, application of SP-303T ointment effected no significant improvement in the clinical course of 9 AIDS patients with acyclovir-unresponsive HSV infection.

Open study of AL-721 treatment of HIV-infected subjects with generalized lymphadenopathy syndrome: an eight week open trial and follow-up.

AL-721 is a lipid compound composed of neutral lipids, phosphatidylcholine and phosphatidylethanolamine in a 7:2:1 ratio. The objective of this open study was to evaluate the effects of AL-721 in vivo in an 8-week open trial in which 10 g twice daily was administered on a low fat diet to eight HIV-infected subjects with lymphadenopathy syndrome (LAS). Serial lymphocyte cocultivation studies in 7 patients with initial culture positivity appeared to demonstrate reduction of reverse transcriptase peak counts in 5 with the trough noted in 4 at 8 weeks and in one at 4 weeks following termination of therapy. The mean values for all 7 patients revealed a baseline value of 73,419 with decrease to a low of 27418 at 8 weeks. Mean levels of total lymphocytes, T-4, T-8 and T-11 cells were not altered but lymphoproliferative responses to concanavalin A and pokeweed mitogens appeared to be augmented in 4 of the 8 subjects in association with AL-721 treatment. No side effects were noted. In a subsequent follow-up study using a normal diet in the same subjects lymphocyte cocultivation and mitogen-induced responses were less consistently affected when 15 g twice daily AL-721 was readministered. In addition, serum HIV p24 antigen and CD4 levels were not altered during both the 8-week open and subsequent AL-721 readministration. Four of the 8 patients have progressed to AIDS over the subsequent 14 months.

Use and efficacy of tuberculosis infection control practices at hospitals with previous outbreaks of multidrug-resistant tuberculosis.

OBJECTIVE: To evaluate the implementation and efficacy of selected Centers for Disease Control and Prevention guidelines for preventing spread of Mycobacterium tuberculosis. DESIGN: Analysis of prospective observational data. SETTING: Two medical centers where outbreaks of multidrug-resistant tuberculosis (TB) had occurred. PARTICIPANTS: All hospital inpatients who had active TB or who were placed in TB isolation and healthcare workers who were assigned to selected wards on which TB patients were treated. METHODS: During 1995 to 1997, study personnel prospectively recorded information on patients who had TB or were in TB isolation, performed observations of TB isolation rooms, and recorded tuberculin skin-test results of healthcare workers. Genetic typing of M tuberculosis isolates was performed by restriction fragment-length polymorphism analysis. RESULTS: We found that only 8.6% of patients placed in TB isolation proved to have TB; yet, 19% of patients with pulmonary TB were not isolated on the first day of hospital admission. Specimens were ordered for acid-fast bacillus smear and results received promptly, and most TB isolation rooms were under negative pressure. Among persons entering TB isolation rooms, 44.2% to 97.1% used an appropriate (particulate, high-efficiency particulate air or N95) respirator, depending on the hospital and year; others entering the rooms used a surgical mask or nothing. We did not find evidence of transmission of TB among healthcare workers (based on tuberculin skin-test results) or patients (based on epidemiological investigation and genetic typing). CONCLUSIONS: We found problems in implementation of some TB infection control measures, but no evidence of healthcare-associated transmission, possibly in part because of limitations in the number of patients and workers studied. Similar evaluations should be performed at hospitals treating TB patients to find inadequacies and guide improvements in infection control.

Effect of bambermycins on quantity, prevalence, duration, and antimicrobial resistance of Salmonella typhimurium in experimentally infected broiler chickens.

Twenty broiler chickens were fed bambermycins (Flavomycin; an antibiotic produced by Streptomyces) at the rate of 3 g/ton (US) for 63 days, and 20 control birds were fed nonmedicated feed. The birds were inoculated (dosed) on the 10th and 11th feeding day with Salmonella typhimurium. The study evaluated the effects of bambermycins on Salmonella incidence, shedding, and antimicrobial resistance. Bambermycins had no effect on body weights, duration of shedding of salmonellae, number of salmonellae shed on postdosing day 3, tissue recoverability of salmonellae, and total number of resistance patterns. Bambermycins resulted in the decrease of salmonellae to be more gradual; however, both treatments were comparable at the end of the study. The majority of S typhimurium from bambermycins-treated birds maintained the original antibiogram of streptomycin, sulfadiazine, and nalidixic acid. The salmonellae isolated from the control birds were more resistant to 2 drugs (varying antibiograms). Bambermycins as a feed additive in broiler diets given at the dose level of 3 g/ton had no detrimental effects based on salmonellae shedding and antimicrobial resistance.

Influence of salinomycin on incidence, shedding, and antimicrobial resistance of Salmonella typhimurium in experimentally infected broiler chicks.

Twenty broiler chickens were fed 80 g/T salinomycin, an antibiotic produced by Streptomyces albus, and 20 birds were fed a control, unmedicated feed. The birds were experimentally infected with Salmonella typhimurium. The study evaluated the effects of salinomycin on Salmonella incidence, shedding, and antimicrobial resistance. Salinomycin had no effect on body weights, length of time salmonellae were shed, number of salmonellae shed on postdosing day 3, salmonellae tissue recoverability, or on the total number of resistance patterns. Salinomycin caused the decline of salmonellae to be more gradual; however, both treatments were comparable at the end of the study. The majority of isolated from birds receiving salinomycin maintained the original S. typhimurium antibiogram of streptomycin, sulfadiazine, and nalidixic acid. The salinomycin salmonellae were more susceptible to tetracycline, amikacin, carbenicillin, gentamicin, and cephalothin. The multiple resistance patterns of eight and nine drugs tended to be more prevalent among salmonellae from control birds than salinomycin treated birds. The antibiotic salinomycin appears to be an acceptable feed additive in broilers at the level of 80 g/T based on these results of its effects on salmonellae shedding and antimicrobial resistance.

Effects of sho-saiko-to on production of prostaglandin E2 (PGE2), leukotriene B4 (LTB4) and superoxide from peripheral monocytes and polymorphonuclear cells isolated from HIV infected individuals.

The effects of Sho-saiko-to (SST), a traditional Chinese medicine, on the production of PGE2 from monocytes, LTB4 and superoxide from polymorphonuclear cells (PMNC) in HIV infected individuals were studied. SST inhibited the production of PGE2 from monocytes stimulated by opsonized zymosan in all groups including the healthy control group and also inhibited the production of superoxide from PMNC after stimulation with FMLP. On the other hand, SST enhanced the production of LTB4 when PMNC were stimulated by the calcium ionophore A23187. These results suggest that SST has different effects on the production of prostanoids or superoxide from monocytes and PMNC. Furthermore, our data indicates that inhibition of PGE2 or superoxide production will lead to indirect suppression of HIV, and enhancement of LTB4 will contribute to the upregulation of the immune reaction in HIV infected individuals.

Extensional flow of hyaluronic acid solutions in an optimized microfluidic cross-slot device.

We utilize a recently developed microfluidic device, the Optimized Shape Cross-slot Extensional Rheometer (OSCER), to study the elongational flow behavior and rheological properties of hyaluronic acid (HA) solutions representative of the synovial fluid (SF) found in the knee joint. The OSCER geometry is a stagnation point device that imposes a planar extensional flow with a homogenous extension rate over a significant length of the inlet and outlet channel axes. Due to the compressive nature of the flow generated along the inlet channels, and the planar elongational flow along the outlet channels, the flow field in the OSCER device can also be considered as representative of the flow field that arises between compressing articular cartilage layers of the knee joints during running or jumping movements. Full-field birefringence microscopy measurements demonstrate a high degree of localized macromolecular orientation along streamlines passing close to the stagnation point of the OSCER device, while micro-particle image velocimetry is used to quantify the flow kinematics. The stress-optical rule is used to assess the local extensional viscosity in the elongating fluid elements as a function of the measured deformation rate. The large limiting values of the dimensionless Trouton ratio, Tr ∼ O(50), demonstrate that these fluids are highly extensional-thickening, providing a clear mechanism for the load-dampening properties of SF. The results also indicate the potential for utilizing the OSCER in screening of physiological SF samples, which will lead to improved understanding of, and therapies for, disease progression in arthritis sufferers.

From ultra-soft slime to hard {alpha}-keratins: The many lives of intermediate filaments.

Intermediate filaments are filaments 10 nm in diameter that make up an important component of the cytoskeleton in most metazoan taxa. They are most familiar for their role as the fibrous component of α-keratins such as skin, hair, nail, and horn but are also abundant within living cells. Although they are almost exclusively intracellular in their distribution, in the case of the defensive slime produced by hagfishes, they are secreted. This article surveys the impressive diversity of biomaterials that animals construct from intermediate filaments and will focus on the mechanisms by which the mechanical properties of these materials are achieved. Hagfish slime is a dilute network of hydrated mucus and compliant intermediate filament bundles with ultrasoft material properties. Within the cytoplasm of living cells, networks of intermediate filaments form soft gels whose elasticity arises via entropic mechanisms. Single intermediate filaments or bundles are also elastic, but substantially stiffer, exhibiting modulus values similar to that of rubber. Hard α-keratins like wool are stiffer still, an effect that is likely achieved via dehydration of the intermediate filaments in these epidermal appendages. The diverse mechanisms described here have been employed by animals to generate materials with stiffness values that span an impressive eleven orders of magnitude.

Ex vivo rheology of spider silk.

We investigate the rheological properties of microliter quantities of the spinning material extracted ex vivo from the major ampullate gland of a Nephila clavipes spider using two new micro-rheometric devices. A sliding plate micro-rheometer is employed to measure the steady-state shear viscosity of approximately 1 microl samples of silk dope from individual biological specimens. The steady shear viscosity of the spinning solution is found to be highly shear-thinning, with a power-law index consistent with values expected for liquid crystalline solutions. Calculations show that the viscosity of the fluid decreases 10-fold as it flows through the narrow spinning canals of the spider. By contrast, measurements in a microcapillary extensional rheometer show that the transient extensional viscosity (i.e. the viscoelastic resistance to stretching) of the spinning fluid increases more than 100-fold during the spinning process. Quantifying the properties of native spinning solutions provides new guidance for adjusting the spinning processes of synthetic or genetically engineered silks to match those of the spider.

Microbial Quality of Ground and Comminuted, Raw and Cooked Turkey Meat 1.

The microbial quality of ground and comminuted turkey meat was examined using raw meat and meat after two cooking times. Eight triplicate samples were obtained from a commercial processing plant over an 8-month period and analyzed for aerobic plate count (APC), coliforms, Escherichia coli , Staphylococcus aureus , Clostridium perfringens and Salmonella . The APC for 29%of the raw ground and 0% of the raw comminuted turkey meat samples was greater than 5.0 × 106/g. Raw ground and comminuted meat yielded a mean coliform most probable number (MPN) of 2.2 × 102 and 6.2 × 102/g respectively. Mean E. coli MPNs per gram were 12 for raw ground and 49 for raw comminuted meat. Twenty-five percent of the 24 raw ground samples, and 46% of the comminuted samples exceeded 50 E. coli MPN/g. S aureus was isolated from 25% of the raw ground and 54% of raw comminuted samples. Salmonellae were isolated from 8% of the raw ground samples and 12% of raw comminuted samples. C. perfringens was isolated from 50 and 55% of 40 ground and 40 comminuted meat samples, respectively. Cooking reduced the microbial numbers and isolation frequency from all samples.

The fine structure of lipofuscin in the mouse hippocampus.

Lipofuscin was ultrastructurally evaluated in the hippocampus of C57B1/6 male mice at 8, 14, 20 and 24 months of age. The mice were anesthetized, perfused intracardially with 3% glutaraldhyde, and routinely processed for transmission electron microscopic evaluation. Lipofuscin was found in the hippocampus of mice of all age groups. Granules were small and randomly dispersed in the younger animals with clustered complexes being present in the older ones. Lipofuscin was present in neurons, neuroglia, and endothelial cells. Pigment granules in the older mice were observed adjacent to capillaries, were found in vacuolating cytoplasmic structures of pericytes but were not associated with microtubules. This morphological evidence supports the normal removal of lipofuscin from the central nervous system by phagocytosis and enzymatic digestion.

Laboratory evaluation of the Anderson Technical semiautomated susceptibility testing system.

Anderson Technical, Inc. has developed rapid, semiautomated equipment for antimicrobial susceptibility testing. A total of 310 fresh clinical bacterial isolates (226 gram-negative and 75 gram-positive) were tested with the Anderson Technical system and compared with those of Micro-Media Systems, Inc. For the gram-positive organisms, 74.3% of the test pairs had identical minimum inhibitory concentration values, whereas 99.1 and 0.9% of the test pairs had minimal inhibitory concentration values differing by less than or equal to 1 and greater than 1 dilution level, respectively. Identical minimum inhibitory concentration values were obtained for 67.2% of the gram-negative test pairs, whereas 97.6 and 2.4% differed by less than or equal to 1 and greater than 1 dilution level, respectively. For all organisms tested, 98.0% differed by less than or equal to 1 dilution level. The Anderson Technical equipment proved to be a rapid and flexible system for microdilution testing.