Effects of hydrogen permeation on the mechanical characteristics of electroless nickel-plated free-cutting steel for application to the hydrogen valves of hydrogen fuel cell electric vehicles.

Electroless nickel plating is a suitable technology for the hydrogen industry because electroless nickel can be mass-produced at a low cost. Investigating in a complex environment where hydrogen permeation and friction/wear work simultaneously is necessary to apply it to hydrogen valves for hydrogen fuel cell vehicles. In this research, the effects of hydrogen permeation on the mechanical characteristics of electroless nickel-plated free-cutting steel (SUM 24L) were investigated. Due to the inherent characteristics of electroless nickel plating, the damage (cracks and delamination of grain) and micro-particles by hydrogen permeation were clearly observed at the grain boundaries and triple junctions. In particular, the cracks grew from grain boundary toward the intergranualr. This is because the grain boundaries and triple junctions are hydrogen permeation pathways and increasing area of the hydrogen partial pressure. As a result, its surface roughness increased by a maximum of two times, and its hardness and adhesion strength decreased by hydrogen permeation. In particular, hydrogen permeation increased the friction coefficient of the electroless nickel-plated layer, and the damage caused by adhesive wear was significantly greater, increasing the wear depth by up to 5.7 times. This is believed to be due to the decreasing in wear resistance of the electroless nickel plating layer damaged by hydrogen permeation. Nevertheless, the Vickers hardness and the friction coefficient of the electroless nickel plating layer were improved by about 3 and 5.6 times, respectively, compared with those of the free-cutting steel. In particular, the electroless nickel-plated specimens with hydrogen embrittlement exhibited significantly better mechanical characteristics and wear resistance than the free-cutting steel.

Isolation of Two Plasticizers, Bis(2-ethylhexyl) Terephthalate and Bis(2-ethylhexyl) Phthalate, from Capparis spinosa L. Leaves.

Many plants have been known to be contaminated and accumulate plasticizers from the environment, including water sources, soil, and atmosphere. Plasticizers are used to confer elasticity and flexibility to various fiber and plastic products. Consumption of plasticizers can lead to many adverse effects on human health, including reproductive and developmental toxicity, endocrine disruption, and cancer. Herein, we report for the first time that two plasticizers, bis(2-ethylhexyl) terephthalate (DEHT) and bis(2-ethylhexyl) phthalate (DEHP), have been isolated from the leaves of Capparis spinosa L. (the caper bush), a plant that is widely used in food seasonings and traditional medicine. 297 mg/kg of DEHT and 48 mg/kg of DEHP were isolated from dried and grounded C. spinosa L. leaves using column chromatography and semi-preparative high-performance liquid chromatography. Our study adds to the increase in the detection of plasticizers in our food and medicinal plants and to the alarming concern about their potential adverse effects on human health.

Bimetallic Hyaluronate-Modified Au@Pt Nanoparticles for Noninvasive Photoacoustic Imaging and Photothermal Therapy of Skin Cancer.

Although spherical gold (Au) nanoparticles have remarkable photothermal conversion efficiency and photostability, their weak absorption in the near-infrared (NIR) region and poor penetration into deep tissues have limited further applications to NIR light-mediated photoacoustic (PA) imaging and noninvasive photothermal cancer therapy. Here, we developed bimetallic hyaluronate-modified Au-platinum (HA-Au@Pt) nanoparticles for noninvasive cancer theranostics by NIR light-mediated PA imaging and photothermal therapy (PTT). The growth of Pt nanodots on the surface of spherical Au nanoparticles enhanced the absorbance in the NIR region and broadened the absorption bandwidth of HA-Au@Pt nanoparticles by the surface plasmon resonance (SPR) coupling effect. In addition, HA facilitated the transdermal delivery of HA-Au@Pt nanoparticles through the skin barrier and enabled clear tumor-targeted PA imaging. Compared to conventional PTT via injection, HA-Au@Pt nanoparticles were noninvasively delivered into deep tumor tissues and completely ablated the targeted tumor tissues by NIR light irradiation. Taken together, we could confirm the feasibility of HA-Au@Pt nanoparticles as a NIR light-mediated biophotonic agent for noninvasive skin cancer theranostics.

Synthesis and biological evaluation of tert-butyl ester and ethyl ester prodrugs of L-γ-methyleneglutamic acid amides for cancer.

In cancer cells, glutaminolysis is the primary source of biosynthetic precursors. Recent efforts to develop amino acid analogues to inhibit glutamine metabolism in cancer have been extensive. Our lab recently discovered many L-γ-methyleneglutamic acid amides that were shown to be as efficacious as tamoxifen or olaparib in inhibiting the cell growth of MCF-7, SK-BR-3, and MDA-MB-231 breast cancer cells after 24 or 72 h of treatment. None of these compounds inhibited the cell growth of nonmalignant MCF-10A breast cells. These L-γ-methyleneglutamic acid amides hold promise as novel therapeutics for the treatment of multiple subtypes of breast cancer. Herein, we report our synthesis and evaluation of two series of tert-butyl ester and ethyl ester prodrugs of these L-γ-methyleneglutamic acid amides and the cyclic metabolite and its tert-butyl esters and ethyl esters on the three breast cancer cell lines MCF-7, SK-BR-3, and MDA-MB-231 and the nonmalignant MCF-10A breast cell line. These esters were found to suppress the growth of the breast cancer cells, but they were less potent compared to the L-γ-methyleneglutamic acid amides. Pharmacokinetic (PK) studies were carried out on the lead L-γ-methyleneglutamic acid amide to establish tissue-specific distribution and other PK parameters. Notably, this lead compound showed moderate exposure to the brain with a half-life of 0.74 h and good tissue distribution, such as in the kidney and liver. Therefore, the L-γ-methyleneglutamic acid amides were then tested on glioblastoma cell lines BNC3 and BNC6 and head and neck cancer cell lines HN30 and HN31. They were found to effectively suppress the growth of these cancer cell lines after 24 or 72 h of treatment in a concentration-dependent manner. These results suggest broad applications of the L-γ-methyleneglutamic acid amides in anticancer therapy.

Streptomyces distallicus, a Potential Microbial Biolarvicide.

Infected mosquitos from the genus Aedes have become one of the world's most influential contributors to human morbidity and death. To explore new biopesticides with activity against Aedes aegypti, Streptomyces distallicus, a species related to the subspecies group of Streptomyces netropsis, was investigated. Six metabolites, aureothin, allo-aureothin, deoxyaureothin, 4',7-dihydroxy isoflavone, 2-methyl-5-(3-indolyl)oxazole, and 2-ethyl-5-(3-indolyl)oxazole were isolated, and chemical structures, were elucidated based on one- and two-dimensional NMR spectroscopy analyses and HRMS. The A. aegypti larvicidal activity of these compounds was evaluated. Only two isomeric compounds, aureothin and allo-aureothin, showed larvicidal activity against A. aegypti with LC50 values of 1.5 and 3.1 ppm for 24 h post-treatment, respectively, and 3.8 and 7.4 ppm for 48 h post-treatment, respectively. The crude extract of S. distallicus also demonstrated potent larvicidal activity with LC50 values of 1.46 and 1.2 ppm for 24 and 48 h post-treatment, respectively. Deoxyaureothin, a furan ring reduced form of aureothin, showed no activity against A. aegypti. The hybrid imported fire ants activity of aureothin was also evaluated, but it did not show any activity at the highest dose of 62.5 µg/g. Described here is the first report on a bioassay-directed investigation of the secondary metabolites of S. distallicus and biological evaluation of isolated compounds aureothin and its isomer and intermediates as potential microbial larvicides. S. distallicus and crude extracts thereof are a promising source of potential microbial biolarvicides.

Influence of Glow-Discharge Nitrided Temperatures of Cast Stainless Steel for Cavitation-Erosion Enhancement in Seawater.

In this work, corrosion resistance and cavitation-erosion characteristics were investigated by applying plasma ion nitriding technique to cast stainless steels used as materials of high speed rotors under seawater environment. Plasma ion nitriding was performed for 10 h at various temperature parameters with 25% N2 and 75% H2 gas ratio. The cavitation-erosion experiment was carried out under vibration amplitude of 30 °C and sea water temperature of 25 °C according to modified ASTM G32-92. The yN phase that improves corrosion resistance and mechanical properties was formed at the all of experimnetal temperatures after plasma ion nitriding treatment. The crystallite size of phases was calculated through the XRD patterns according to Scherrer formula and obtained smallest nano size of yN phase at 450 °C. Cavitation-erosion resistance was enhanced up to 450 °C but was deteriorated at 500 °C.

Solid Particle Erosion Characteristics of 2.25Cr-1Mo Steel Aged at 750 °C.

This study evaluated the solid particle erosion characteristics of 2.25Cr-1Mo steel with aging time. Aging was performed at 750 °C until 100 h. Specimens aged at each time were characterized by microstructure analysis and Micro-Vickers hardness. An erosion experiment was conducted using 100~200 µm of stainless steel shot at a flow velocity of 20 m/s for 4 h. A consequently, a microstructure degradation phenomenon in which Cr-rich carbide was coarsened occurred, and the surface hardness decreased by 45%. With a decrease in the hardness, the solid particle erosion damage increased and the erosion damage type changed.

Structure-activity-distribution relationship study of anti-cancer antimycin-type depsipeptides.

Small-molecule natural products have been an essential source of pharmaceuticals to treat human diseases, but very little is known about their behavior inside dynamic, live human cells. Here, we demonstrate the first structure-activity-distribution relationship (SADR) study of complex natural products, the anti-cancer antimycin-type depsipeptides, using the emerging bioorthogonal Stimulated Raman Scattering (SRS) Microscopy. Our results show that the intracellular enrichment and distribution of these compounds are driven by their potency and specific protein targets, as well as the lipophilic nature of compounds.

Characterization of Cavitation-Erosion Resistance of Plasma Ion Nitrided 316L Stainless Steel Under Shock Wave in Seawater.

In this study, the characteristics of cavitation-erosion resistance of 316L stainless steel after plasma ion nitriding at various temperatures were investigated in natural seawater. Plasma ion nitriding was performed with N2 and H2 at a ratio of 1:4 from 400 to 500 °C for 10 hours. Micro-Vickers hardness measurement showed that the mechanical properties were improved by increasing hardness due to the formation of expanded austenite (S-phase) at 400 °C and 450 °C and γ'-Fe4N and CrN phases at 500 °C. In the cavitation-erosion test, weight loss and damage rate decreased with increasing nitriding temperatures up to 450 °C, while the depth of damage was found to be increased at 500 °C. The lowest weight loss and damage depth were obtained at 450 °C, which measured the thickest layer of γN phase. At 500 °C, cavitation-erosion damage was significantly occurred due to the internal residual stress accumulated during the plasma ion nitriding.

Influence of Sensitization on Mechanical Properties of AISI 304 Stainless Steel under High-Temperature.

This study investigated influence of sensitization on the mechanical properties of AISI 304 stainless steel. The small and tensile specimens were isothermally aged at 650 °C for up to 1000 hours. Microstructure and precipitates of these specimens were characterized by scanning electrode microscope with energy dispersive X-ray spectroscopy. The degree of sensitization of aged specimens was measured by double loop electrochemical potentiodynamic reactivation method. The tensile test was conducted to evaluate mechanical properties of these specimens. With the progress of aging, the degree of sensitization value drastically increased to more than 50% as Cr-rich carbides were precipitated in the austenite grain boundaries. Also, the mechanical properties were degraded, and fracture mode drastically changed from ductile to brittle. As a result, the surface damage and degradation of mechanical properties were correlated with the degree of sensitization value.

Usefulness of Blood Cultures and Radiologic Imaging Studies in the Management of Patients with Community-Acquired Acute Pyelonephritis.

BACKGROUND: The objective of this study was to examine the usefulness of blood cultures and radiologic imaging studies for developing therapeutic strategies in community-acquired acute pyelonephritis (CA-APN) patients. MATERIALS AND METHODS: We prospectively collected the clinical data of CA-APN patients who visited 11 hospitals from March 2010 to February 2011. RESULTS: Positive urine and blood cultures were obtained in 69.3% (568/820) and 42.7% (277/648), respectively, of a total of 827 CA-APN patients. Blood culture identified the urinary pathogen in 60 of 645 (9.3%) patients for whom both urine and blood cultures were performed; the organisms isolated from urine were inconsistent with those from blood in 11 and only blood cultures were positive in 49 patients. Final clinical failure was more common in the bacteremic patients than the non-bacteremic ones (8.0% vs. 2.7%, P = 0.003), as was hospital mortality (3.6% vs. 0.3%, P = 0.003). Likewise, durations of hospitalization and fever were significantly longer. Bacteremia was independent risk factor for mortality (OR 9.290, 1.145-75.392, P = 0.037). With regard to radiologic studies, the detection rate of APN was 84.4% (445/527) by abdominal computed tomography and 40% (72/180) by abdominal ultrasonography. Eighty-one of 683 patients (11.9%) were found to have renal abscess, perinephric abscess, urolithiasis, hydronephorosis/hydroureter or emphysematous cystitis, which could potentially impact on clinical management. Patients with Pitt score ≥ 1, flank pain or azotemia were significantly more likely to have such structural abnormalities. CONCLUSION: Blood cultures are clinically useful for diagnosis of CA-APN, and bacteremia is predictive factor for hospital mortality. Early radiologic imaging studies should be considered for CA-APN patients with Pitt scores ≥1, flank pain or azotemia.

Chemically accessible hsp90 inhibitor that does not induce a heat shock response.

Recent cancer therapies have focused on targeting biology networks through a single regulatory protein. Heat shock protein 90 (hsp90) is an ideal oncogenic target as it regulates over 400 client proteins and cochaperones. However, clinical inhibitors of hsp90 have had limited success; the primary reason being that they induce a heat shock response. We describe the synthesis and biological evaluation of a new hsp90 inhibitor, SM253. The previous generation on which SM253 is based (SM145) has poor overall synthetic yields, low solubility, and micromolar cytotoxicity. By comparison SM253 has relatively high overall yields, good aqueous solubility, and is more cytotoxic than its parent compound. Verification that hsp90 is SM253's target was accomplished using pull-down and protein folding assays. SM253 is superior to both SM145 and the clinical candidate 17-AAG as it decreases proteins related to the heat shock response by 2-fold, versus a 2-4-fold increase observed when cells are treated with 17-AAG.

Solid phase versus solution phase synthesis of heterocyclic macrocycles.

Comparing a solution phase route to a solid phase route in the synthesis of the cytotoxic natural product urukthapelstatin A (Ustat A) confirmed that a solid phase method is superior. The solution phase approach was tedious and involved cyclization of a ridged heterocyclic precursor, while solid phase allowed the rapid generation of a flexible linear peptide. Cyclization of the linear peptide was facile and subsequent generation of three oxazoles located within the structure of Ustat A proved relatively straightforward. Given the ease with which the oxazole Ustat A precursor is formed via our solid phase approach, this route is amenable to rapid analog synthesis.