Zeolitic Imidazolate Framework-Derived Pt-Co in Nanofibrous Networks as Stable Oxygen Reduction Electrocatalysts with Low Pt Loading

Proton-exchange membrane fuel cell technology is a key component in the future zero-carbon energy system, generating power from carbon-free fuels, such as green hydrogen. However, the high Pt loading in conventional fuel cell electrodes to maintain electrocatalytic activity and durability, especially on the cathode for oxygen reduction, is the Achilles heel for the worldwide deployment of fuel cell technologies. To minimize Pt consumption for oxygen reduction, we synthesized Pt-Co-based electrocatalysts with meticulous structuring from micrometer to the atomic scale based on reaction pathways. The resulting Pt-Co-based electrocatalysts contain only 1.9 wt% Pt, which is 20 times lower than the conventional Pt-C catalysts for fuel cells. By utilizing electrospinning and in situ synthesis, we anchored three-dimensionally structured zeolitic imidazolate frameworks on continuously connected nanofibrous electrospun mats. The Pt-Co@Pt-free nanowire (PC@PFN) electrocatalysts contain Pt-Co nanoparticles (NPs) and non-Pt elements, Co-containing sites comprising NPs, nanoclusters, and N-coordinated Co single atoms. Despite the ultralow Pt loading in PC@PFN, the mass activity exceeds the U.S. Department of Energy 2025 target by 2.8 times and retains 85.5% of the initial activity after 80,000 durability test cycles, possibly owing to synergistic reaction pathways between Pt and non-Pt sites.

Chronic pain, chronic stress and substance use: overlapping mechanisms and implications

Chronic pain is among the most common reasons adults in the U.S. seek medical care. Despite chronic pain's substantial impact on individuals' physical, emotional, and financial wellness, the biologic underpinnings of chronic pain remain incompletely understood. Such deleterious impact on an individuals' wellness is also manifested in the substantial co-occurrence of chronic stress with chronic pain. However, whether chronic stress and adversity and related alcohol and substance misuse increases risk of developing chronic pain, and, if so, what the overlapping psychobiological processes are, is not well understood. Individuals suffering with chronic pain find alleviation through prescription opioids as well as non-prescribed cannabis, alcohol, and other drugs to control pain, and use of these substances have grown significantly. Substance misuse also increases experience of chronic stress. Thus, given the evidence showing a strong correlation between chronic stress and chronic pain, we aim to review and identify overlapping factors and processes. We first explore the predisposing factors and psychologic features common to both conditions. This is followed by examining the overlapping neural circuitry of pain and stress in order to trace a common pathophysiologic processes for the development of chronic pain and its link to substance use. Based on the previous literature and our own findings, we propose a critical role for ventromedial prefrontal cortex dysfunction, an overlapping brain area associated with the regulation of both pain and stress that is also affected by substance use, as key in the risk of developing chronic pain. Finally, we identify the need for future research in exploring the role of medial prefrontal circuits in chronic pain pathology. Critically, in order to alleviate the enormous burden of chronic pain without exacerbating the co-occurring substance misuse crisis, we emphasize the need to find better approaches to treat and prevent chronic pain.

Alcohol withdrawal symptoms predict corticostriatal dysfunction that is reversed by prazosin treatment in alcohol use disorder

Chronic alcohol use increases risk of alcohol withdrawal symptoms (AW) and disrupts stress biology and resilient coping, thereby promoting excessive alcohol intake. Chronic alcohol intake and multiple alcohol detoxifications are known to impair brain medial prefrontal cortex (mPFC) and striatal functioning, regions involved in regulating stress, craving and alcohol intake. In two related studies, we examined whether AW predicts this functional brain pathology and whether Prazosin versus Placebo treatment may reverse these effects. In Study 1, patients with Alcohol Use Disorder (AUD) (N = 45) with varying AW levels at treatment entry were assessed to examine AW effects on corticostriatal responses to stress, alcohol cue and neutral visual images with functional magnetic resonance imaging (fMRI). In Study 2, 23 AUD patients entering a 12-week randomised controlled trial (RCT) of Prazosin, an alpha1 adrenergic antagonist that decreased withdrawal-related alcohol intake in laboratory animals, participated in two fMRI sessions at pretreatment and also at week 9-10 of chronic treatment (Placebo: N = 13; Prazosin: N = 10) to assess Prazosin treatment effects on alcohol-related cortico-striatal dysfunction. Study 1 results indicated that higher AW predicted greater disruption in brain mPFC and striatal response to stress and alcohol cues (p < 0.001, family-wise error [FWE] correction) and also subsequently greater heavy drinking days (HDD) in early treatment (p < 0.01). In Study 2, Prazosin versus Placebo treatment reversed mPFC-striatal dysfunction (p < 0.001, FWE), which in turn predicted fewer drinking days (p < 0.01) during the 12-week treatment period. These results indicate that AW is a significant predictor of alcohol-related prefrontal-striatal dysfunction, and Prazosin treatment reversed these effects that in turn contributed to improved alcohol treatment outcomes.

Adopting Back Reduction Current as an Additional Output Signal for Achieving Photoelectrochemical Differentiated Detection

Photoelectrochemical (PEC) sensors are usually based on a single output signal, that is, the photocurrent change caused by the (photoelectro)chemical reaction between target analytes and photoelectrodes. However, the photocurrent may be influenced by redox species other than the target analyte; therefore, modifying the surface of photoelectrodes with probes that selectively bind to the analyte is essential. Moreover, even though various surface modification methods have been developed, distinguishing molecularly similar chemicals using PEC sensing systems remains a significant challenge. To address these selectivity issues, we proposed a photoanode-based PEC sensor that utilizes a cathodic transient current as a second output signal in addition to the photocurrent, which arises from the back reduction of photo-oxidized species. Factors influencing the back reduction were investigated by observing the transient photocurrent of hematite photoanodes in the presence of model redox probes. The chemical environment around the electrode-electrolyte interface was manipulated by altering the electrolyte composition or modifying the electrode surface. The favorable interaction between the electrode surface and redox species led to an increase in the extent of back reduction and the cathodic transient current. In addition, the extent of back reduction also depends on the chemical identity of the redox species, such as the kinetics of subsequent chemical reactions. Therefore, the synergistic combination of the photocurrent and the cathodic transient current enabled the differentiated detection of various catecholamine neurotransmitters with a single pristine photoelectrode, which has never been achieved using traditional PEC methods. Revisiting the transient photocurrent can complement conventional PEC applications and offers possibilities for more effective semiconductor-based applications.

Enhanced H2 Evolution at Patterned MoSx-Modified Si-Based Photocathodes by Incorporating the Interfacial 3D Nanostructure of Ag

Photoelectrochemical cells represent one of the promising ways to renewably produce hydrogen (H₂) as a future chemical fuel. The design of a catalyst/semiconductor junction for the hydrogen evolution reaction (HER) requires various factors for high performance. In catalytic materials, an intrinsic activity with fast charge-transfer kinetics is important. Additionally, their thermodynamic property and physical adhesion should be compatible with the underlying semiconductor for favorable band alignment and stability during vigorous H₂ bubble formation. Moreover, catalysts, especially non-noble materials that demand a large amount of loading, should be adequately dispersed on the semiconductor surface to allow sufficient light absorption to generate excitons. One of the methods to simultaneously satisfy these conditions is to adopt an interfacial layer between the semiconductor and active materials in HER. The interfacial layer efficiently extracts the electrons from the semiconductor and conveys those to the catalytically active surface. We demonstrate Ag as a 3D interfacial nanostructure of patterned MoS_x catalysts for photoelectrochemical HER. The nanostructured porous Ag layer was introduced by a simple chemical process, followed by photoelectrochemical deposition of MoS_x to form MoS_x/Ag nanostructures in cross-shaped catalyst pattern arrays. Ag modulated the surface electronic property of MoS_x to improve the reaction kinetics as well as helped a charge transport at the Ag|p-Si(100) junction. The physically stable adhesion of catalysts was also achieved despite the ∼40 nm thick catalysts owing to the interfacial Ag nanostructure. This work contributes to further understand the complex multistep HER from light absorption to charge transfer to protons, helping to develop cost-effective and efficient photocathodes.

Comparison of major histocompatibility complex-B variability in Sri Lankan indigenous chickens with five global chicken populations using MHC-B SNP panel

In the present study, we investigated the major histocompatibility complex (MHC)-B haplotypes diversity of Sri Lankan indigenous chickens from three different geographical sites consisting of highly mixed populations using 90 SNPs in the MHC-B region. A total of 48 haplotypes were identified. Those included 37 novel haplotypes and 11 previously identified 'standard' haplotypes. The MHC-linked marker, LEI0258, had 23 alleles showing less diversity than defined by MHC-B SNP haplotypes. Among those identified haplotypes, five standard haplotypes-BSNP-O02, BSNP-M01, BSNP-A04, BSNP-K03, BSNP-T04-were most commonly observed, suggesting past introgression of imported breeds. Comparison of the MHC-B haplotypes of Sri Lankan and four other global populations with previously defined haplotypes indicated the sharing of 23 standard haplotypes with common origins. Novel haplotypes are population-specific and not shared among the geographical boundaries. Backyard indigenous chickens are unselected, highly crossbred, and generally thrive under dynamic environmental conditions. Hence free-range production systems may be responsible for maintaining high diversity in the MHC-B region with novel haplotypes.

Functional Integration of Catalysts with Si Nanowire Photocathodes for Efficient Utilization of Photogenerated Charge Carriers

Low-cost catalysts with high activity and durability are necessary to achieve efficient large-scale energy conversion in photoelectrochemical cell (PEC) systems. An additional factor that governs the construction of photoelectrodes for PECs is the spatial control of the catalysts for efficient utilization of photogenerated charge carriers. Here, we demonstrate spatial decoupling of the light-absorbing and catalytic components in hierarchically structured Si-based photocathodes for the hydrogen evolution reaction (HER). By simply modifying a well-known metal-assisted chemical etching procedure, we fabricated a Si nanowire (NW) array-based photocathode with Ag-Pt catalysts at the base and small amounts of the Pt catalyst at the NW tips. This approach simultaneously mitigates the parasitic light absorption by the catalytic layers and recombination of charge carriers owing to the long transport distance, resulting in improved photoelectrochemical HER performance under simulated AM 1.5G illumination.

Universal Suzuki-Miyaura Catalyst-Transfer Polymerization for Precision Synthesis of Strong Donor/Acceptor-Based Conjugated Polymers and Their Sequence Engineering

Catalyst-transfer polymerization has revolutionized the field of polymer synthesis due to its living character, but for a given catalyst system, the polymer scope is rather narrow. Herein we report a highly efficient Suzuki-Miyaura catalyst-transfer polymerization (SCTP) that covers a wide range of monomers from electron-rich (donor, D) to electron-deficient (acceptor, A) (hetero)arenes by rationally designing boronate monomers and using commercially available Buchwald RuPhos and SPhos Pd G3 precatalysts. Initially, we optimized the controlled polymerization of 3,4-propylenedioxythiophene (ProDOT), benzotriazole (BTz), quinoxaline (QX), and 2,3-diphenylquinoxaline (QXPh) by introducing new boronates, such as 4,4,8,8-tetramethyl-1,3,6,2-dioxazaborocane and its N-benzylated derivative, to modulate the reactivity and stability of the monomers. As a result, PProDOT, PBTz, PQX, and PQXPh were prepared with controlled molecular weight and narrow dispersity (Đ < 1.29) in excellent yield (>85%). A detailed investigation of the polymer structures using ¹H NMR and MALDI-TOF spectrometry supported the chain-growth mechanism and the high initiation efficiency of the SCTP method. In addition, the use of RuPhos-Pd showing excellent catalyst-transfer ability on both D/A monomers led to unprecedented controlled D-A statistical copolymerization, thereby modulating the HOMO energy level (from -5.11 to -4.80 eV) and band gap energy (from 1.68 to 1.91 eV) of the resulting copolymers. Moreover, to demonstrate the living nature of SCTP, various combinations of D-A and A-A block copolymers (PBTz-b-PProDOT, PQX-b-PProDOT, and PQX-b-PBTz) were successfully prepared by the sequential addition method. Finally, simple but powerful one-shot D-A block copolymerization was achieved by maximizing the rate difference between a fast-propagating pinacol boronate donor and a slow-propagating acceptor to afford well-defined poly(3-hexylthiophene)-b-poly(benzotriazole).

Robust and High Spatial Resolution Light Addressable Electrochemistry Using Hematite (α-Fe2O3) Photoanodes

Light addressable/activated electrochemistry (LAE) has recently attracted attention as it can provide spatially resolved electrochemical information without using pre-patterned electrodes whose sizes and positions are unchangeable. Here, we propose hematite (α-Fe₂O₃) as the photoanode for LAE, which does not require any sort of surface modification for protection or facilitating charge transfer. As experimentally confirmed with various redox species, hematite is stable enough to be used for repetitive electroanalytical measurements. More importantly, it offers exceptionally high spatial resolution so that the "virtual electrode" is exactly as large as the light spot owing to the short diffusion length of the minority carriers. Quantitative analysis of dopamine in this study shows that the hematite-based photoanode is a promising platform for many potential LAE applications including spatially selective detection of oxidizable biomolecules.

Electrostatic Screening of Charged Defects in Monolayer MoS2

Defects in monolayer transition-metal dichalcogenides (TMDCs) may lead to unintentional doping, charge-carrier trapping, and nonradiative recombination. These effects impair electronic and optoelectronic technologies. Here we show that charged defects in MoS₂ monolayers can be effectively screened when they are in contact with an ionic liquid (IL), leading to an increase in photoluminescence (PL) yield by up to two orders of magnitude. The extent of this PL enhancement by the IL correlates with the brightness of each pretreated sample. We propose the existence of two classes of nonradiative recombination centers in monolayer MoS₂: (i) charged defects that relate to unintentional doping and may be electrostatically screened by ILs and (ii) neutral defects that remain unaffected by the presence of ILs.

Novel deletion mutation of HLA-B*40:02 gene in acquired aplastic anemia

Despite prevalence of clonal evolution in patients with aplastic anemia (AA), somatic mutation of human leukocyte antigen (HLA) gene is rarely reported. Herein, we reported a case of acquired AA (aAA) harboring a new four-base-pair deletion mutation within exon 4 of HLA-B*40:02 leading to frameshift and premature stop codon. The HLA-B*40:02 mutant allele was detected in the patient's peripheral blood sample not in patient's buccal epithelial cells. The patient received allogenic hematopoietic stem cell transplantation (HSCT) from HLA-matched sibling donor. On day 30 after HSCT, the mutant HLA allele was not detected by high-resolution sequence-based HLA typing. Serial chimerism analyses showed mixed chimeric status indicative of coexisting donor and recipient hematopoietic cells. Our data could provide additional support in view of pathophysiology of aAA that somatic mutation of HLA-B*40:02 allele is one of the possible origin of clonal escape to evade immune attack in patient with aAA.

Food image-induced brain activation is not diminished by insulin infusion

Background/Objective

The obesity epidemic appears to be driven in large part by our modern environment inundated by food cues, which may influence our desire to eat. While insulin decreases food intake in both animals and humans, the effect of insulin on motivation for food in the presence of food cues is not known. Therefore, the aim of this study was to evaluate the effect of an intravenous insulin infusion on the brain response to visual food cues, hunger and food craving in non-obese human subjects.

Subjects/Methods

Thirty-four right-handed healthy non-obese subjects (19F/15M, age: 29±8 yrs.; BMI: 23.1±2.1 kg/m2) were divided in two groups matched by age, and BMI: the Insulin Group (18 subjects) underwent a hyperinsulinemic-euglycemic-clamp, and the control group (16 subjects) received an intravenous saline infusion, while viewing high and low-calorie food and non-food pictures during a functional MRI scan. Motivation for food was determined via analogue scales for hunger, wanting and liking ratings.

Results

Food images induced brain responses in the hypothalamus, striatum, amygdala, insula, ventromedial prefrontal cortex (PFC), dorsolateral PFC, and occipital lobe (whole brain correction, P<0.05). Wanting (P<0.001) and liking (P<0.001) ratings were significantly higher for the food than the non-food images, but not different between insulin and saline infusion groups. Hunger ratings increased throughout the MRI scan and correlated with preference for high-calorie food pictures (r=0.70; P<0.001). However neither brain activity nor food craving were affected by hyperinsulinemia or hormonal status (leptin and ghrelin levels) (P=NS).

Conclusion

Our data demonstrate that visual food cues induce a strong response in motivation/reward and cognitive-executive control brain regions in non-obese subjects, but that these responses are not diminished by hyperinsulinemia per se. These findings suggest that our modern food cue saturated environment may be sufficient to overpower homeostatic hormonal signals, and thus contribute to the current obesity epidemic.

Utility of blood pressure genetic risk score in admixed Hispanic samples

Hypertension is strongly influenced by genetic factors. Although hypertension prevalence in some Hispanic sub-populations is greater than in non-Hispanic whites, genetic studies on hypertension have focused primarily on samples of European descent. A recent meta-analysis of 200,000 individuals of European descent identified 29 common genetic variants that influence blood pressure, and a genetic risk score derived from the 29 variants has been proposed. We sought to evaluate the utility of this genetic risk score in Hispanics. The sample set consists of 1994 Hispanics from two cohorts: the Northern Manhattan Study (primarily Dominican/Puerto Rican) and the Miami Cardiovascular Registry (primarily Cuban/South American). Risk scores for systolic and diastolic blood pressure were computed as a weighted sum of the risk alleles, with the regression coefficients reported in the European meta-analysis used as weights. Association of risk score with blood pressure was tested within each cohort, adjusting for age, age squared, sex, and BMI. Results were combined using an inverse-variance meta-analysis. The risk score was significantly associated with blood pressure in our combined sample (p = 5.65 × 10⁻⁴ for systolic and p = 1.65 × 10⁻³ for diastolic) but the magnitude of the regression coefficients varied by degree of European, African, and Native American admixture. Further studies among other Hispanic sub-populations are needed to elucidate the role of these 29 variants and identify additional genetic and environmental factors contributing to blood pressure variability in Hispanics.

Molecular targeting of CSN5 in human hepatocellular carcinoma: a mechanism of therapeutic response

Development of targeted therapy for hepatocellular carcinoma (HCC) remains a major challenge. We have recently identified an elevated expression of the fifth subunit of COP9 signalosome (CSN5) in early HCC as compared to dysplastic stage. In the present study, we explored the possibility of CSN5 being a potential therapeutic target for HCC. Our results show that CSN5 knockdown by small interfering (si) RNA caused a strong induction of apoptosis and inhibition of cell cycle progression in HCC cells in vitro. The downregulation of CSN5 was sufficient to interfere with CSN function as evidenced by the accumulation of neddylated Cullin1 and changes in the protein levels of CSN controlled substrates SKP2, p53, p27 and NF-kB, albeit to a different degree depending on the HCC cell line, which could account for the CSN5 knockdown phenotype. The transcriptomic analysis of CSN5 knockdown signature showed that the anti-proliferative effect was driven by a common subset of molecular alterations including downregulation of CDK6 and ITGB1, which were functionally interconnected with key oncogenic regulators MYC and TGFβ1 involved in the control of proliferation, apoptotic cell death and HCC progression. Consistent with microarray analysis, western blotting revealed that CSN5 depletion increased phosphorylation of Smad 2/3, key mediators of TGFβ1 signaling, decreased the protein levels of ITGB1, CDK6, and cyclin D1 and caused reduced expression of anti-apoptotic Bcl-2 while elevating the levels of pro-apoptotic Bak. A chemically modified variant of CSN5 siRNA was then selected for in vivo application based on the growth inhibitory effect and minimal induction of unwanted immune response. Systemic delivery of the CSN5 3/8 variant by stable-nucleic-acid-lipid-particles (SNALP) significantly suppressed the tumor growth in Huh7-luc⁺ orthotopic xenograft model. Taken together, these results indicate that CSN5 plays a pivotal role in HCC pathogenesis and maybe an attractive molecular target for systemic HCC therapy.

A randomized phase II study of FOLFOX or FOLFIRI.3 as second-line therapy in patients with advanced pancreatic cancer previously treated with gemcitabine-based chemotherapy

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Background: Only few clinical trials have been conducted in patients with advanced pancreatic cancer after failure of first-line gemcitabine-based chemotherapy. We conducted a randomized phase II trial of modified FOLFOX vs. modified FOLFIRI.3 as second-line regimen for the patients with gemcitabine refractory pancreatic cancer ( NCT00786006 ). Methods: Patients with advanced pancreatic adenocarcinoma previously treated with gemcitabine were randomly assigned to FOLFOX or FOLFIRI.3 stratifying by age (≤ 65 vs. >65), performance status (0–1 vs. 2) and prior response to gemcitabine (PR/SD vs. PD). FOlFIRI.3 regimen consisted of Irinotecan 70 mg/m2 (over 60 min) D1, leucovorin 400 mg/m2 (over 2h) D1, 5-FU 2000 mg/m2 (over 46 hours) from D1, then irinotecan 70 mg/m2 (over 60 min) at the end of the 5-FU infusion every two week. FOLFOX regimen is composed of oxaliplatin 85 mg/m2 (over 120 min) D1, LV 400 mg/m2 D1, 5-FU 2,000 mg/m2 (over 46 hours) every two week. The primary end-point was 6-month overall survival (P0=20%) and Simon-Wittes-Ellenberg design was used to calculate the sample size (29 evaluable patients for each treatment arm). Results: From January 2007 to December 2008, sixty patients were enrolled and randomized to FOLFOX (N=30) or FOLFIRI.3 (N=30). Baseline characteristics were well balanced between each arm; median age 56 (35–60) vs. 56 yo (37–73); ECOG PS 0/1/2, 5/24/1 vs. 5/25/0; prior response to gemcitabine-based chemotherapy PR/SD/PD 10/13/7 vs. 10/11/9. With a median follow-up period of 6.0 months (95% CI, 4.7–7.3) the median overall survival was 4.0 months in both group (HR=0.95, 95% CI 0.52–1.75) with 6-month survival rates of 25% and 20%, respectively. The median PFS was 1.4 months for FOLFOX and 1.9 months for FOLFIRI.3 (HR=1.11, 95% CI, 0.64–1.92). Disease control (PR+SD) was achieved in 20% (5/25 in FOLFOX) and 28% (7/25 in FOLFIRI.3) of patients with measurable disease. The incidences of grade 3/4 toxicities were similar in both groups. Conclusions: Both FOLFOX and FOLFIRI.3 were tolerated with manageable toxicity, offering modest activity as second-line treatment of patients with advanced or metastatic pancreatic cancer, previously treated with gemcitabine.

No significant financial relationships to disclose.

Phase II trial of neoadjuvant fixed dose rate (FDR) gemcitabine with capecitabine (GX) combination chemotherapy in locally advanced pancreatic adenocarcinoma (LAPA)

e15553

Background: To determine the efficacy and safety of fixed dose rate (FDR) gemcitabine and capecitaibne (GX) combination chemotherapy for locally advanced pancreatic adenocarcinoma Methods: Patients with histologically confirmed LAPA were eligible for this prospective phase II trial. Dynamic pancreas/pelvic CT, MRI and FDG-PET were undertaken to assess the resectability. EUS was also performed as needed basis. ‘Borderline resectable (BR)’ and ‘unresectable (UR)’ criteria developed by our pancreatico-biliary multidisciplinary management team (PBMMT) and NCCN criteria were used. After confirmation of resectability, patients received 3 cycles of FDR gemcitabine 1,250 mg/m2 on D1 and D8 and capecitabine 950 mg/m2 from D1-D14 every 3 weeks. Thereafter, staging was repeated and patients underwent surgery if the disease was not unresectable. For patients with R0 resection, additional 6 cycles of GX were administered. For patients with R1 resection, chemoradiotherapy (CRT) (54 Gy over 5 weeks with concurrent 5-FU and leucovorin or capecitabine) followed by FDR-GX was administered. Patients with stable or better response to chemotherapy but assessed unresectable at reassessment received additional chemotherapy up to 9 cycles followed by CRT. Results: Between August 2006 and July 2008, 38 eligible patients (14 with BR and 24 with UR based on NCCN criteria; 29 with BR and 9 with UR based on our PBMMT criteria) entered on this study. The median age was 61 yo (42–76) and 71% had cT4 disease. The response to neoadjuvant chemotherapy was PR in 6 (16%), SD in 26 (68%) and PD in 3 (8%). Metabolic response was achieved in 20 patients (53%) with 2 metabolic CR out of 31 evaluable patients. Grade 3 or worse adverse effects were mainly HFS (n=5) and gastrointestinal (n=3) with no grade 4 in severity. Surgery was performed in 9 patients (24.0%, R0=8, R1=1, 6 in NCCN-BR and 3 in NCCN-UR, 9 in PBMMT-BR) and five patients refused surgery although their diseases seemed not to be unresectable. The median PFS was 9.4 months (95% CI, 8.3–10.4) and estimated median OS was 13.5 months (95% CI, 12.4- 14.5). Conclusions: FDR-GX was effective as neoadjuvnat chemotherapy in LAPA with favorable toxicity profile.

No significant financial relationships to disclose.

Polymorphisms of the tumor suppressor gene LSAMP are associated with left main coronary artery disease

Previous association mapping on chromosome 3q13-21 detected evidence for association at the limbic system-associated membrane protein (LSAMP) gene in individuals with late-onset coronary artery disease (CAD). LSAMP has never been implicated in the pathogenesis of CAD. We sought to thoroughly characterize the association and the gene. Non-redundant single nucleotide polymorphisms (SNPs) across the gene were examined in an initial dataset (168 cases with late-onset CAD, 149 controls). Stratification analysis on left main CAD (N = 102) revealed stronger association, which was further validated in a validation dataset (141 cases with left main CAD, 215 controls), a third control dataset (N = 255), and a family-based dataset (N = 2954). A haplotype residing in a novel alternative transcript of the LSAMP gene was significant in all independent case-control datasets (p = 0.0001 to 0.0205) and highly significant in the joint analysis (p = 0.00004). Lower expression of the novel alternative transcript was associated with the risk haplotype (p = 0.0002) and atherosclerosis burden in human aortas (p = 0.0001). Furthermore, silencing LSAMP expression in human aortic smooth muscle cells (SMCs) substantially augmented SMC proliferation (p<0.01). Therefore, the risk conferred by the LSAMP haplotype appears to be mediated by LSAMP down-regulation, which may promote SMC proliferation in the arterial wall and progression of atherosclerosis.

Application of medium class land cover maps to AVSWAT2000 for the prediction of inflow, CBOD, TN and TP for Yongdam Lake, Korea

This study tests the efficacy of using medium class land cover maps vs. the large class maps produced by the Korean Ministry of Environment for prediction of flow and CBOD, TN and TP concentrations. AVSWAT2000 was chosen as a model to process information for a sample site, Yongdam Lake watershed area, Korea. The watershed was divided into 11 sub-watersheds, as was done for implementation of the Total Waste Load Management Act by the Korean government. Calibration of AVSWAT2000 was performed using a trial-and-error method, by comparing the root mean square errors of the observed data and calculated results. This study suggests that AVSWAT2000 can be successfully applied in estimating pollutant load considering hydrologic and site-specific conditions of watersheds. With further study, this approach may be applied to improve watershed-scale water quality management strategies, especially for TMDL developments.

Photoreduction and reoxidation of the three iron-sulfur clusters of reaction centers of green sulfur bacteria

Iron-sulfur clusters are the terminal electron acceptors of the photosynthetic reaction centers of green sulfur bacteria and photosystem I. We have studied electron-transfer reactions involving these clusters in the green sulfur bacterium Chlorobium tepidum, using flash-absorption spectroscopic measurements. We show for the first time that three different clusters, named F(X), F(1), and F(2), can be photoreduced at room temperature during a series of consecutive flashes. The rates of electron escape to exogenous acceptors depend strongly upon the number of reduced clusters. When two or three clusters are reduced, the escape is biphasic, with the fastest phase being 12-14-fold faster than the slowest phase, which is similar to that observed after single reduction. This is explained by assuming that escape involves mostly the second reducible cluster. Evidence is thus provided for a functional asymmetry between the two terminal acceptors F(1) and F(2). From multiple-flash experiments, it was possible to derive the intrinsic recombination rates between P840(+) and reduced iron-sulfur clusters: values of 7, 14, and 59 s(-1) were found after one, two and three electron reduction of the clusters, respectively. The implications of our results for the relative redox potentials of the three clusters are discussed.

Investigation of inclusion complexation of paclitaxel by cyclohenicosakis-(1-->2)-(beta-D-glucopyranosyl), by cyclic-(1-->2)-beta-D-glucans (cyclosophoraoses), and by cyclomaltoheptaoses (beta-cyclodextrins)

Inclusion complexation of the poorly soluble drug, paclitaxel, was investigated with various host cyclooligosaccharides such as a family of isolated neutral cyclohenicosakis-(1-->2)-(beta-D-glucopyranosyl) (cyclic-(1-->2)-beta-D-glucans, cyclosophoraoses), dimethyl cyclomaltoheptaose (cyclodextrins, DM-beta-CD) and hydroxypropyl cyclomaltoheptaose (cyclodextrins, HP-beta-CD). Quantitative analysis with high-performance liquid chromatography (HPLC) indicated that all three cyclic oligosaccharides could increase the solubility of paclitaxel, where DM-beta-CD gave the best results and a family of cyclosophoraoses and HP-beta-CD, both gave similar results. Complexation of host molecules with paclitaxel was studied by NMR and fluorescence spectroscopic analyses. NMR spectroscopic analysis showed that the aromatic regions of paclitaxel experienced noticeable changes of the chemical shifts or peak shapes upon interaction with host molecules. The relatively bulky cyclosophoraoses allowed favorable accessibility to either the B-ring or A-ring of paclitaxel, while DM-beta-CD and HP-beta-CD allowed accessibility to all the aromatic rings including the C ring. The interaction of DM-beta-CD with paclitaxel greatly increased the fluorescence intensity compared with other host molecules, suggesting the more effective partitioning of a moderate fluorophore into a hydrophobic cluster adjacent to the C-ring of paclitaxel.

Purification of ferredoxins and their reaction with purified reaction center complex from the green sulfur bacterium Chlorobium tepidum

Four ferredoxin (Fd) fractions, namely, FdA-D were purified from the green sulfur bacterium Chlorobium tepidum. Their absorption spectra are typical of 2[4Fe-4S] cluster type Fds with peaks at about 385 and 280 nm and a shoulder at about 305 nm. The A(385)/A(280) ratios of the purified Fds were 0.76-0.80. Analysis of the N-terminal amino acid sequences of these Fds (15-25 residues) revealed that those of FdA and FdB completely agree with those deduced from the genes, fdx3 and fdx2, respectively, found in this bacterium (Chung and Bryant, personal communication). The N-terminal amino acid sequences of FdC and FdD (15 residues) were identical, and agree with that deduced from the gene fdx1 (Chung and Bryant, personal communication). The A(385) values of these Fds were unchanged when they were stored for a month at -80 degrees C under aerobic conditions and decreased by 10-15% when they were stored for 6 days at 4 degrees C under aerobic conditions, indicating that they are not extremely unstable. In the presence of Fd-NADP(+) reductase from spinach, and a purified reaction center (RC) preparation from C. tepidum composed of five kinds of polypeptides, these Fds supported the photoreduction of NADP(+) at room temperature with the following K(m) and V(max) (in micromol NADP(+) micromol BChl a(-1) h(-1)): FdA, 2.0 microm and 258; FdB, 0.49 microM and 304; FdC, 1.13 microM and 226; FdD, 0.5 microM and 242; spinach Fd, 0.54 microM and 183. The V(max) value of FdB was more than twice that previously reported for purified RC preparations from green sulfur bacteria.

Electron transfer kinetics in purified reaction centers from the green sulfur bacterium Chlorobium tepidum studied by multiple-flash excitation

Reaction center preparations from the green sulfur bacterium Chlorobium tepidum, which contain monoheme cytochrome c, were studied by flash-absorption spectroscopy in the near-UV, visible, and near-infrared regions. The decay kinetics of the photooxidized primary donor P840(+), together with the amount of photooxidized cytochrome c, were analyzed along a series of four flashes spaced by 1 ms: 95% of the P840(+) was reduced by cytochrome c with a t(1/2) of approximately 65 micros after the first flash, 80% with a t(1/2) of approximately 100 micros after the second flash, and 23% with a t(1/2) of approximately 100 micros after the third flash; after the fourth flash, almost no cytochrome c oxidation occurred. The observed rates, the establishment of redox equilibrium after each flash, and the total amount of photooxidizable cytochrome c are consistent with the presence of two equivalent cytochrome c molecules per photooxidizable P840. The data are well fitted assuming a standard free energy change DeltaG degrees of -53 meV for electron transfer from one cytochrome c to P840(+), DeltaG degrees being independent of the oxidation state of the other cytochrome c. These observations support a model with two monoheme cytochromes c which are symmetrically arranged around the reaction center core. From the ratio of menaquinone-7 to the bacteriochlorophyll pigment absorbing at 663 nm, it was estimated that our preparations contain 0.6-1.2 menaquinone-7 molecules per reaction center. However, no transient signal due to menaquinone could be observed between 360 and 450 nm in the time window from 10 ns to 4 micros. No recombination reaction between the primary partners P840(+) and A(0)(-) could be detected under normal conditions. Such a recombination was observed (t(1/2) approximately 19 ns) under highly reducing conditions or after accumulation of three electrons on the acceptor side during a series of flashes, showing that the secondary acceptors can stabilize three electrons. From our data, there is no evidence for involvement of menaquinone in charge separation in the reaction center of green sulfur bacteria.