Gold-Decorated Block Copolymer Microspheres with Controlled Surface Nanostructures

Kim, Minsoo P.,Kang, Dong Jin,Jung, Dae-Woong,Kannan, Aravindaraj G.,Kim, Ki-Hyun,Ku, Kang Hee,Jang, Se Gyu,Chae, Weon-Sik,Yi, Gi-Ra,Kim, Bumjoon J. American Chemical Society 2012 ACS NANO Vol.6 No.3

<P>Gold-decorated block copolymer microspheres (BCP-microspheres) displaying various surface morphologies were prepared by the infiltration of Au precursors into polystyrene-<I>b</I>-poly(4-vinylpyridine) (PS-<I>b</I>-P4VP) microspheres. The microspheres were fabricated by emulsifying the PS-<I>b</I>-P4VP polymers in chloroform into a surfactant solution in water, followed by the evaporation of chloroform. The selective swelling of the P4VP domains in the microspheres by the Au precursor under acidic conditions resulted in the formation of Au-decorated BCP-microspheres with various surface nanostructures. As evidenced by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) measurements, dotted surface patterns were formed when microspheres smaller than 800 nm were synthesized, whereas fingerprint-like surface patterns were observed with microspheres larger than 800 nm. Au nanoparticles (NPs) were located inside P4VP domains near the surfaces of the prepared microspheres, as confirmed by TEM. The optical properties of the BCP-microspheres were characterized using UV–vis absorption spectroscopy and fluorescence lifetime measurements. A maximum absorption peak was observed at approximately 580 nm, indicating that Au NPs are densely packed into P4VP domains on the microspheres. Our approach for creating Au-NP-hybrid BCP-microspheres can be extended to other NP systems such as iron-oxide or platinum NPs. These precursors can also be selectively incorporated into P4VP domains and induce the formation of hybrid BCP-microspheres with controlled surface nanostructures.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2012/ancac3.2012.6.issue-3/nn300194z/production/images/medium/nn-2012-00194z_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn300194z'>ACS Electronic Supporting Info</A></P>

Notch signaling and neuronal death in stroke

Arumugam, Thiruma V.,Baik, Sang-Ha,Balaganapathy, Priyanka,Sobey, Christopher G.,Mattson, Mark P.,Jo, Dong-Gyu Elsevier 2018 Progress in neurobiology Vol.165 No.-

<P><B>Abstract</B></P> <P>Ischemic stroke is a leading cause of morbidity and death, with the outcome largely determined by the amount of hypoxia-related neuronal death in the affected brain regions. Cerebral ischemia and hypoxia activate the Notch1 signaling pathway and four prominent interacting pathways (NF-κB, p53, HIF-1α and Pin1) that converge on a conserved DNA-associated nuclear multi-protein complex, which controls the expression of genes that can determine the fate of neurons. When neurons experience a moderate level of ischemic insult, the nuclear multi-protein complex up-regulates adaptive stress response genes encoding proteins that promote neuronal survival, but when ischemia is more severe the nuclear multi-protein complex induces genes encoding proteins that trigger and execute a neuronal death program. We propose that the nuclear multi-protein transcriptional complex is a molecular mediator of neuronal hormesis and a target for therapeutic intervention in stroke.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We review the roles of Notch in the neuropathology of ischemic stroke. </LI> <LI> We discuss the mechanisms for how Notch interacts with other gene transcription regulators such as HIF-1α, NF-κB, p53 and Pin1 following a stroke. </LI> <LI> We introduce a novel concept of a multi-protein complex which controls the expression of genes that determine the fate of neurons in stroke. </LI> <LI> We discuss if and how the multi-protein complex may regulate neuronal plasticity and resilience during the remodeling phase following stroke. </LI> <LI> We conclude with a perspective on how this research may lead to novel approaches for clinical intervention in ischemic stroke. </LI> </UL> </P>

Effects of exogenous phytase and xylanase, individually or in combination, and pelleting on nutrient digestibility, available energy content of wheat and performance of growing pigs fed wheat-based diets

Yang, Y.Y.,Fan, Y.F.,Cao, Y.H.,Guo, P.P.,Dong, B.,Ma, Y. X. Asian Australasian Association of Animal Productio 2017 Animal Bioscience Vol.30 No.1

Objective: Two experiments were conducted to determine the effects of adding exogenous phytase and xylanase, individually or in combination, as well as pelleting on nutrient digestibility, available energy content of wheat and the performance of growing pigs fed wheat-based diets. Methods: In Experiment 1, forty-eight barrows with an initial body weight of $35.9{\pm}0.6kg$ were randomly assigned to a $2{\times}4$ factorial experiment with the main effects being feed form (pellet vs meal) and enzyme supplementation (none, 10,000 U/kg phytase, 4,000 U/kg xylanase or 10,000 U/kg phytase plus 4,000 U/kg xylanase). The basal diet contained 97.8% wheat. Pigs were placed in metabolic cages for a 7-d adaptation period followed by a 5-d total collection of feces and urine. Nutrient digestibility and available energy content were determined. Experiment 2 was conducted to evaluate the effects of pelleting and enzymes on performance of wheat for growing pigs. In this experiment, 180 growing pigs ($35.2{\pm}9.0kg\;BW$) were allocated to 1 of 6 treatments according to a $2{\times}3$ factorial treatment arrangement with the main effects being feed form (meal vs pellet) and enzyme supplementation (0, 2,500 or 5,000 U/kg xylanase). Results: In Experiment 1, there were no interactions between feed form and enzyme supplementation. Pelleting reduced the digestibility of acid detergent fiber (ADF) by 6.4 percentage units (p<0.01), increased the digestibility of energy by 0.6 percentage units (p<0.05), and tended to improve the digestibility of crude protein by 0.5 percentage units (p = 0.07) compared with diets in mash form. The addition of phytase improved the digestibility of phosphorus (p<0.01) and calcium (p<0.01) by 6.9 and 7.6 percentage units respectively compared with control group. Adding xylanase tended to increase the digestibility of crude protein by 1.0 percentage units (p = 0.09) and increased the digestibility of neutral detergent fiber (NDF) (p<0.01) compared with control group. Supplementation of the xylanase-phytase combination improved the digestibility of phosphorus (p<0.01) but impaired NDF digestibility (p<0.05) compared with adding xylanase alone. In Experiment 2, adding xylanase increased average daily gain (p<0.01) and linearly improved the feed:gain ratio (p<0.01) compared with control group. Conclusion: Pelleting improved energy digestibility but decreased ADF digestibility. Adding xylanase increased crude protein digestibility and pig performance. Phytase increased the apparent total tract digestibility of phosphorus and calcium. The combination of phytase-xylanase supplementation impaired the effects of xylanase on NDF digestibility.

Cerebral Vasospasm Affects Arterial Critical Closing Pressure

Varsos, Georgios V,Budohoski, Karol P,Czosnyka, Marek,Kolias, Angelos G,Nasr, Nathalie,Donnelly, Joseph,Liu, Xiuyun,Kim, Dong-Joo,Hutchinson, Peter J,Kirkpatrick, Peter J,Varsos, Vassilis G,Smielewski SAGE Publications 2015 Journal of cerebral blood flow and metabolism Vol.35 No.2

<P> The effect of cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (SAH) on critical closing pressure (CrCP) has not been fully delineated. Using cerebral impedance methodology, we sought to assess the behavior of CrCP during CVS. As CrCP expresses the sum of intracranial pressure (ICP) and vascular wall tension, we also explored its role in reflecting changes in vascular tone occurring in small vessels distal to spasm. This retrospective analysis was performed using recordings from 52 patients, diagnosed with CVS through transcranial Doppler measurements. Critical closing pressure was calculated noninvasively using arterial blood pressure and blood flow velocity. Outcome was assessed at both discharge and 3 months after ictus with the Glasgow Outcome Scale. The onset of CVS caused significant decreases in CrCP ( P=0.025), without any observed significant changes in ICP ( P=0.134). Vasospasm induced asymmetry, with CrCP ipsilateral to CVS becoming significantly lower than contralateral ( P=0.025). Unfavorable outcomes were associated with a significantly lower CrCP after the onset of CVS (discharge: P=0.014; 3 months after SAH: P=0.020). Critical closing pressure is reduced in the presence of CVS in both temporal and spatial assessments. As ICP remained unchanged during CVS, reduced CrCP most probably reflects a lower wall tension in dilated small vessels distal to spasm. </P>

Inhibition of the prostaglandin-degrading enzyme 15-PGDH potentiates tissue regeneration

Zhang, Yongyou,Desai, Amar,Yang, Sung Yeun,Bae, Ki Beom,Antczak, Monika I.,Fink, Stephen P.,Tiwari, Shruti,Willis, Joseph E.,Williams, Noelle S.,Dawson, Dawn M.,Wald, David,Chen, Wei-Dong,Wang, Zhengh American Association for the Advancement of Scienc 2015 Science Vol.348 No.6240

<P><B>A shot in the arm for damaged tissue</B></P><P>Tissue damage can be caused by injury, disease, and even certain medical treatments. There is great interest in identifying drugs that accelerate tissue regeneration and recovery, especially drugs that might benefit multiple organ systems. Zhang <I>et al.</I> describe a compound with this desired activity, at least in mice (see the Perspective by FitzGerald). SW033291 promotes recovery of the hematopoietic system after bone marrow transplantation, prevents the development of ulcerative colitis in the intestine, and accelerates liver regeneration after hepatic surgery. It acts by inhibiting an enzyme that degrades prostaglandins, lipid signaling molecules that have been implicated in tissue stem cell maintenance.</P><P><I>Science</I>, this issue 10.1126/science.aaa2340; see also p. 1208</P><P>Agents that promote tissue regeneration could be beneficial in a variety of clinical settings, such as stimulating recovery of the hematopoietic system after bone marrow transplantation. Prostaglandin PGE2, a lipid signaling molecule that supports expansion of several types of tissue stem cells, is a candidate therapeutic target for promoting tissue regeneration in vivo. Here, we show that inhibition of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a prostaglandin-degrading enzyme, potentiates tissue regeneration in multiple organs in mice. In a chemical screen, we identify a small-molecule inhibitor of 15-PGDH (SW033291) that increases prostaglandin PGE2 levels in bone marrow and other tissues. SW033291 accelerates hematopoietic recovery in mice receiving a bone marrow transplant. The same compound also promotes tissue regeneration in mouse models of colon and liver injury. Tissues from 15-PGDH knockout mice demonstrate similar increased regenerative capacity. Thus, 15-PGDH inhibition may be a valuable therapeutic strategy for tissue regeneration in diverse clinical contexts.</P>

Effect of HNO₃ functionalization on large scale graphene for enhanced tri-iodide reduction in dye-sensitized solar cells

Das, Santanu,Sudhagar, P.,Ito, Eisuke,Lee, Dong-yoon,Nagarajan, S.,Lee, Sang Yun,Kang, Yong Soo,Choi, Wonbong The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.38

<P>Improving the electro-catalytic activity of graphene has recently been the subject of intense research for high efficiency flexible energy storage and conversion devices. We report the synthesis of a large scale graphene film by a CVD method and its electro-catalytic activity by functionalization with HNO<SUB>3</SUB> for a high efficiency electrochemical electrode in DSSCs. We found that HNO<SUB>3</SUB> functionalization on graphene enhances the tri-iodide reduction rate by three times in a dye sensitized solar cell compared to that of pristine graphene. The X-ray photoelectron spectroscopy (XPS) and ultra-violet photoemission spectroscopy (UPS) studies confirm the covalently attached C–OH, C(O)OH and NO<SUP>3−</SUP> moieties to carbon atoms through sp<SUP>2</SUP>–sp<SUP>3</SUP> hybridization, and this results in the Fermi level shift towards p-type doping. We believe that the covalently attached functional groups cause the enrichment of the electro-catalytically active sites along with facilitating the charge transfer kinetics from graphene counter electrodes to redox couples. The enhanced catalytic effect of functionalized graphene offers insights into new types of electrode development opportunities in graphene based energy storage and conversion devices.</P> <P>Graphic Abstract</P><P>Nitric acid doped p-type graphene shows higher electro-catalytic activity towards tri-iodide reduction in dye sensitized solar cells. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm32481d'> </P>

Directed Self-Assembly of Asymmetric Block Copolymers in Thin Films Driven by Uniaxially Aligned Topographic Patterns

Lee, Dong-Eun,Ryu, Jaegeon,Hong, Dongki,Park, Soojin,Lee, Dong Hyun,Russell, Thomas P. American Chemical Society 2018 ACS NANO Vol.12 No.2

<P>We present a simple, versatile approach to generate highly ordered nanostructures of block copolymers (BCPs) using rubbed surfaces. A block of poly(tetrafluoroethylene) (PTFE) was dragged across a flat substrate surface above the melting point of PTFE transferring a highly aligned PTFE topographic pattern to the substrate. Si wafer, glass, and polyimide films were used as substrates. Thin films of cylinder-forming asymmetric polystyrene-<I>block</I>-poly(2-vinylpyridine) copolymers (S2VPs) were solvent annealed on the surfaces having the transferred surface pattern to induce their directed self-assembly. Cylinders of P2VP oriented normal to the surface are markedly aligned along the rubbing direction and used as templates to generate extremely uniform arrays of various metallic nanoparticles of gold, silver, and platinum over a large area.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2018/ancac3.2018.12.issue-2/acsnano.7b08226/production/images/medium/nn-2017-08226j_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn7b08226'>ACS Electronic Supporting Info</A></P>

Solar Water Splitting with a Hydrogenase Integrated in Photoelectrochemical Tandem Cells

Nam, Dong Heon,Zhang, Jenny Z.,Andrei, Virgil,Kornienko, Nikolay,Heidary, Nina,Wagner, Andreas,Nakanishi, Kenichi,Sokol, Katarzyna P.,Slater, Barnaby,Zebger, Ingo,Hofmann, Stephan,Fontecilla‐,Ca John Wiley and Sons Inc. 2018 Angewandte Chemie Vol.57 No.33

<P><B>Abstract</B></P><P>Hydrogenases (H<SUB>2</SUB>ases) are benchmark electrocatalysts for H<SUB>2</SUB> production, both in biology and (photo)catalysis in vitro. We report the tailoring of a p‐type Si photocathode for optimal loading and wiring of H<SUB>2</SUB>ase through the introduction of a hierarchical inverse opal (IO) TiO<SUB>2</SUB> interlayer. This proton‐reducing Si|IO‐TiO<SUB>2</SUB>|H<SUB>2</SUB>ase photocathode is capable of driving overall water splitting in combination with a photoanode. We demonstrate unassisted (bias‐free) water splitting by wiring Si|IO‐TiO<SUB>2</SUB>|H<SUB>2</SUB>ase to a modified BiVO<SUB>4</SUB> photoanode in a photoelectrochemical (PEC) cell during several hours of irradiation. Connecting the Si|IO‐TiO<SUB>2</SUB>|H<SUB>2</SUB>ase to a photosystem II (PSII) photoanode provides proof of concept for an engineered Z‐scheme that replaces the non‐complementary, natural light absorber photosystem I with a complementary abiotic silicon photocathode.</P>

Circulating TNF receptors predict cardiovascular disease in patients with chronic kidney disease

Bae, Eunjin,Cha, Ran-Hui,Kim, Yong C.,An, Jung N.,Kim, Dong K.,Yoo, Kyung D.,Lee, Su M.,Kim, Myoung-Hee,Park, Jung T.,Kang, Shin-Wook,Park, Jae Y.,Lim, Chun S.,Kim, Yon S.,Yang, Seung H.,Lee, Jung P. Williams & Wilkins Co 2017 Medicine Vol.96 No.19

<P>We prospectively recruited 984 patients with CKD from 11 centers between 2006 and 2012. The levels of cTNFR1 and cTNFR2 were determined by performing an enzyme-linked immunosorbent assay. During the mean follow-up period of 4 years, 36 patients experienced a CVD event. The median serum concentrations of cTNFR1 and cTNFR2 were 2703.4 (225.6-13,057.7) and 5661.0 (634.9-30,599.6) pg/mL, respectively, and the cTNFR1 level was closely correlated with the cTNFR2 level (r=0.86, P < .0001). The urinary protein-to-creatinine ratio (UPCR) and estimated glomerular filtration rate (eGFR) were significantly correlated with the cTNFR2 level (r=0.21 for UPCR, r=-0.67 for eGFR; P<.001 for all). Similar correlations were observed for serum cTNFR1 (r=0.21 for UPCR, r=-0.75 for eGFR; P < .001 for all). In the Cox proportional hazard analyses, cTNFR1 (hazard ratio [HR] 2.506, 95% confidence interval [CI] 1.186-5.295, P=.016) and cTNFR2 (HR4.156, 95% CI 1.913-9.030, P < .001) predictedCVDrisk even after adjustment for clinical covariates, such as UPCR, eGFR, and high-sensitivity C-reactive protein. cTNFR1 and 2 are associated with CVD and other risk factors in CKD, independently of eGFR and UPCR. Furthermore, cTNFRs could be relevant predictors of CVD in CKD patients.</P>

가금육의 이용과 가금육 제품의 특성에 관한 연구 - 칠면조육과 돈육으로 제조한 Ham 의 특성 -

오동환(Dong Hwan Oh),(P . J . Bechtel) 한국축산학회 1988 한국축산학회지 Vol.30 No.6

Chunked and formed ham products were processed using commercial cure and spices with lean pork and turkey thigh meat. Five treatments were evaluated: 100% pork(P), 100% turkey(T), 75%P + 25% T, 50% P + 50%T, and 25% P + 75% T. Meat was cut into cubes, amulsion coated, mixed, stuffed into casing and cooked to 70℃ and stored in a lighted 4℃ retail case for 0, 30 and 60 days. Sensory scores indicated all products ware in the acceptable range for tenderness, juiciness and ham flavor; however, the 100% T product had increased of flavor (P$lt;0,05) and lower overall acceptability (P$lt;0.05). Visual characteristics flavored the higher % T products (P$lt;0.05). TBA values were in the acceptable range. Product color decreased during storage. Total plate counts from samples stored 0, 30 and 60 days did not show treatment effects. Results from this study indicate that composite pork-turkey products can be manufactured that have acceptable sensory, microbiological, and functional properties.