Improved synthesis and characterization of saturated branched‐chain fatty acid isomers

The development of viable technologies for producing green products from renewable fats and oils is highly desirable since such materials can serve as replacements for non‐renewable and poorly biodegradable petroleum‐based products. Mixtures of saturated branched‐chain fatty acid isomers (sbc‐FAs), commonly referred to as isostearic acid, are important intermediates for the production of biodegradable lubricants, cosmetics, emollients, and hydraulic fluids. Present methods for producing sbc‐FAs, however, often give low yields of sbc‐FAs or sbc‐FA preparations with a high content of dimer acid fatty acid co‐products. This study reports an improved route to synthesizing sbc‐FAs from monounsaturated fatty acids using a modified H‐Ferrierite zeolite catalyst in conjunction with small amounts of triphenylphosphine additive. The yields of sbc‐FAs (up to 80 wt%) and co‐products (up to15 wt%) were determined using a modification of a previously reported GC method. A more detailed analysis of the distribution of sbc‐FA isomers in the products was made by the combined use of GC × GC‐TOF‐MS. Additionally, it was found that the H‐Ferrierite zeolite catalyst was recyclable and reusable up to 10 times without significant loss of activity and selectivity for sbc‐FAs.     

A biosensor based an micromechanical interrogation of living cells

The authors have demonstrated that living cells can be reliably cultured directly onto atomic force microscope (AFM) cantilevers. The cells are inclined to grow on both sides of the surface, and the cantilevers must be treated to deter such two-sided growth. Preliminary data acquired with the AFM demonstrate that these integrated cell/cantilevers are capable of detecting the response of Madine Darby canine kidney (MDCK) cells to different toxins, with response time on the order of several seconds. These results suggest the feasibility of real-time, rapid, and sensitive biomechanical sensors. A separate fluid chamber has been built, which is capable of detecting fluid temperature changes of tenths of a degree. The initial temperature results from the fluid chamber prototype indicate the potential for a low-cost dedicated system     

Factors affecting image acquisition during scanning laser polarimetry

Prognosis of systemic sclerosis (scleroderma, Ssc) is largely depending on involvement of internal organs. Abnormalities of the gastrointestinal tract are found most frequently (85%), especially decreased motility of the oesophagus, which has little impact on the longterm clinical course of Ssc. Pulmonary manifestations can be demonstrated in 40-90% of patients; one must distinguish between pulmonary hypertension or fibrotic lung disease. The heart is affected in 50% of cases. Patchy or diffuse myocardial fibrosis, as well as pericarditis and pericardial effusions can induce symptoms of arrhythmia or congestive heart failure. Renal involvement is associated with increased mortality and occurs in 45% of Ssc, producing proteinuria, hypertension, scleroderma renal crisis and renal failure. In conclusion, involvement of the lungs, heart and kidneys are determining factors for the longterm course of systemic sclerosis.     

Reduced microvascular thrombosis and improved outcome in acute murine stroke by inhibiting GP IIb/IIIa receptor-mediated platelet aggregation

Treatment options in acute stroke are limited by a dearth of safe and effective regimens for recanalization of an occluded cerebrovascular tributary, as well as by the fact that patients present only after the occlusive event is established. We hypothesized that even if the site of major arterial occlusion is recanalized after stroke, microvascular thrombosis continues to occur at distal sites, reducing postischemic flow and contributing to ongoing neuronal death. To test this hypothesis, and to show that microvascular thrombosis occurs as an ongoing, dynamic process after the onset of stroke, we tested the effects of a potent antiplatelet agent given both before and after the onset of middle cerebral arterial (MCA) occlusion in a murine model of stroke. After 45 min of MCA occlusion and 23 h of reperfusion, fibrin accumulates in the ipsilateral cerebral hemisphere, based upon immunoblotting, and localizes to microvascular lumena, based upon immunostaining. In concordance with these data, there is a nearly threefold increase in the ipsilateral accumulation of 111In-labeled platelets in mice subjected to stroke compared with mice not subjected to stroke. When a novel inhibitor of the glycoprotein IIb/IIIa receptor (SDZ GPI 562) was administered immediately before MCA occlusion, platelet accumulation was reduced 48%, and fibrin accumulation was reduced by 47% by immunoblot densitometry. GPI 562 exhibited a dose-dependent reduction of cerebral infarct volumes measured by triphenyltetrazolium chloride staining, as well as improvement in postischemic cerebral blood flow, measured by laser doppler. GPI 562 caused a dose-dependent increase in tail vein bleeding time, but intracerebral hemorrhage (ICH) was not significantly increased at therapeutic doses; however, there was an increase in ICH at the highest doses tested. When given immediately after withdrawal of the MCA occluding suture, GPI 562 was shown to reduce cerebral infarct volumes by 70%. These data support the hypothesis that in ischemic regions of brain, microvascular thrombi continue to accumulate even after recanalization of the MCA, contributing to postischemic hypoperfusion and ongoing neuronal damage.     

Solution structure of human p8MTCP1, a cysteine-rich protein encoded by the MTCP1 oncogene, reveals a new alpha-helical assembly motif

MTCP1 (for Mature-T-Cell Proliferation) is the first gene unequivocally identified in the group of uncommon leukemias with a mature phenotype. The three-dimensional solution structure of the human p8(MTCP1) protein encoded by the MTCP1 oncogene was determined by homonuclear proton two-dimensional NMR methods at 600 MHz. After sequence specific assignments, a total of 931 distance restraints and 57 dihedral restraints were collected. The location of the three previously unassigned disulfide bridges was determined from preliminary DIANA structures, using a statistical analysis of intercystinyl distances. The solution structure of p8(MTCP1) is presented as a set of 30 DIANA structures, further refined by restrained molecular dynamics using a simulated annealing protocol with the AMBER force field. The r.m.s.d. values with respect to the mean structure for the backbone and all heavy atoms for a family of 30 structures are 0.73(+/-0.28) and 1.17(+/-0.23) A, when the structured core of the protein (residues 5 to 63) is considered. The solution structure of p8(MTCP1) reveals an original scaffold consisting of three alpha helices, associated with a new cysteine motif. Two of the helices are covalently paired by two disulfide bridges, forming an alpha-hairpin which resembles an antiparallel coiled-coil. The third helix is oriented roughly parallel to the plane defined by the alpha-antiparallel motif and its axis forms an angle of approximately 60 degrees with respect to the main axis of this motif.     

C18‐unsaturated branched‐chain fatty acid isomers: Characterization and physical properties

Iso‐oleic acid is a mixture of C₁₈‐unsaturated branched‐chain fatty acid isomers with a methyl group on various positions of the alkyl chain, which is the product of the skeletal isomerization reaction of oleic acid and is the intermediate used to make isostearic acid (C₁₈‐saturated branched‐chain fatty acid isomers). Methyl iso‐oleate, a mixture of C₁₈‐unsaturated branched‐chain fatty acid methyl ester isomers, is obtained via acid catalyzed esterification of iso‐oleic acid with methanol. The branched‐chain materials are liquid at room temperature and their “oiliness” property makes them an attractive candidate for the lubricant industry. In this paper, we report characterization of these branched‐chain materials using comprehensive two‐dimensional GC with time‐of‐flight mass spectrometry (GC × GC/TOF‐MS) and their physical and lubricity properties using tribology measurements.     

Flat Lenses Based on 2D Perovskite Nanosheets

Ultrathin flat lenses based on metasurfaces or metamaterials have shown great promise in recent years as essential components in nano-optical system, with capability of abrupt changes of light wavefronts. However, such structural designs require complex nanopatterns and a time-consuming nanofabrication process. In this regard, flat lenses are developed based on 2D perovskite nanosheets, using a cost-effective mask-free femtosecond direct laser writing system. The optical properties of the 2D perovskite are rationally adjusted through facile composition engineering as well as thickness-dependent quantum-size confinement. A diffraction theory model is derived to understand the focusing mechanism of the 2D perovskite nanosheets flat lenses. The as-fabricated lenses exploit the tunable material property variations to effectively manipulate not only the amplitude but also the phase of the incident light to focus into a 3D focal spot with a sub-wavelength resolution in the range of 0.5–0.9λ. The results pave the way toward low-cost and large-scale high-resolution imaging applications in the future.     

The separation of manganese from cobalt by D2EHPA

The separation of manganese from cobalt in sulphate solution by D2EHPA diluted with kerosene is reported. Manganese can be separated by controlling the aqueous and organic pH in the neighborhood of 4.2 and 2.0, respectively. A continuous separation process is proposed. Results indicate that a high degree of separation between manganese and cobalt can be achieved.