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Background/Aims: The objective of this study was to investigate the potential role of IL-17 in the development of nasopharyngeal carcinoma (NPC) and to screen microRNAs (miRNAs) that potentially target IL-17 in NPC cells. Methods: Blood was collected from NPC patients and normal subjects, and plasma IL-17 concentration was quantified by enzyme-linked immunosorbent assay. An immortalized normal human nasopharyngeal epithelial cell line, NP69, was treated with or without human IL-17 (15 ng/mL) for various times, and expression of IL-1β, IL-6, IL-12, and TNF-α mRNA was assessed by real-time reverse transcription PCR. The candidate miRNAs that potentially target IL-17 were predicted by a bioinformatics strategy. The selected miR-135a mimic was transfected into primary NPC cells, and cell proliferation was assessed by MTT assay. Results: The concentration of plasma IL-17 was significantly higher in the NPC patients (92.5 ± 7.3 pg/mL) than in the control subjects (56.8 ± 2.9 pg/mL). In response to IL-17 treatment, the mRNA expression of IL-1β and IL-6 was significantly upregulated and reached a peak at 12 h, followed by a slight decrease at 24 h, while the mRNA expression of IL-12 and TNF-α was significantly upregulated at 12 h and remained high even at 48 h after exposure to IL-17. Moreover, miR-135a specifically targets IL-17 and was dramatically downregulated in NPC cells compared with NP69 cells. Transfection of exogenous miR-135a mimic resulted in significant suppression of IL-17 secretion and subsequent inhibition of NPC cell proliferation. Conclusions: Blood IL-17 was significantly higher in NPC patients compared with normal subjects. Expression of miR-135a in the cancer cells isolated from nasopharyngeal tumors was significantly lower than that in NP69 cells, and suppression of IL-17 by miR-135a mimic resulted in significant inhibition of NPC cell proliferation. These findings suggested that downregulation of miR-135a may contribute to the development of NPC via the mechanism of IL-17 stimulation of proinflammatory cytokine expression. [ABSTRACT FROM AUTHOR]

The European Pharmacopoeia, the U.S. Pharmacopoeia, and the Pharmacopoeia of the People's Republic of China all prescribe a high-performance liquid chromatography-ultraviolet method within a C18 column system for the separation of Azithromycin (AZT) and its related substances. The identification of impurities in the AZT complex was performed according to the relative retention time (RRT) between each impurity and AZT. However, the RRT values of impurities often vary on different types of C18 packing materials and at different column temperatures, which could affect the accurate and fast identification of impurities. In our study, five different commonly used C18 columns as well as nine different column temperature set points were assessed for the analysis of AZT and its related substances. A factorial design was applied to analysis the relationships between column types/column temperatures and RRT value of each impurity. The results showed that the change rates of the RRT values of impurities were different on different columns and at different column temperature set points. Therefore, the current method adopted by the three Pharmacopeias, in which the RRT values were used to identify the related substances, is not suitable to identify the ones in the AZT chromatographic system. [ABSTRACT FROM AUTHOR]

T cell-mediated cancer immunotherapy is dose dependent and optimally requires participation of antigen-specific CD4+ and CD8+ T cells. Here, we isolated tumor-sensitized T cells and activated them in vitro using conditions that led to greater than 108-fold numerical hyperexpansion of either the CD4+ or CD8+ subset while retaining their capacity for in vivo therapeutic efficacy. Murine tumor-draining lymph node (TDLN) cells were segregated to purify the CD62Llow subset, or the CD4+ subset thereof. Cells were then propagated through multiple cycles of anti-CD3 activation with IL-2 + IL-7 for the CD8+ subset, or IL-7 + IL-23 for the CD4+ subset. A broad repertoire of TCR Vβ families was maintained throughout hyperexpansion, which was similar to the starting population. Adoptive transfer of hyper-expanded CD8+ T cells eliminated established pulmonary metastases, in an immunologically specific fashion without the requirement for adjunct IL-2. Hyperexpanded CD4+ T cells cured established tumors in intracranial or subcutaneous sites that were not susceptible to CD8+ T cells alone. Because accessibility and antigen presentation within metastases varies according to anatomic site, maintenance of a broad repertoire of both CD4+ and CD8+ T effector cells will augment the overall systemic efficacy of adoptive immunotherapy [ABSTRACT FROM AUTHOR]

Simple Grignard reagents were applied in copper-catalyzed asymmetric ring-opening reactions of oxabenzonorbornadiene derivatives using spiro phosphoramidite ligands. Excellent anti-stereoselectivities and good enantioselectivities were achieved. [ABSTRACT FROM AUTHOR]

Examines the efficiency of hot filament chemical vapor deposition in obtaining epitaxial oriented growth of diamond on silicon. Confirmation of the epitaxial relationship between the film and substrate using the scanning electron microscopy; Effects of several misorientation angles on single-crystal diamond film growth; Occurrence of strain in the epitaxial interface.

Details the synthesis of spiro diphosphines. Application in asymmetric hydrogenation of ketones; Steps in the catalytic asymmetric hydrogenation of prochiral ketones; Activity and enantioselectivity.

In order to improve the measuring accuracy of the Hemispherical Resonator Gyro under variable temperature, aiming at the problem of "external temperature is unavailable and internal temperature is unmeasurable," a multiple regression based method is proposed for compensating temperature error in the gyro. The relationship between the internal temperature and the resonant frequency of the gyro is analyzed theoretically. According to a constant temperature experiment, a linear relationship between them is derived based on the least square method. The analysis of a temperature-rising experiment shows that the correlation of the gyro output with the internal temperature is much higher than that with the external temperature. Therefore, taking the resonant frequency as an independent variable, a multiple regression model is established for compensating the temperature error. The compensation effect of the model is verified by temperature-rising and temperature-dropping experiments, which show that the output sequence before compensation is not stable, while it is stable after compensation. After compensation, the drift of the gyro decreases by 62.76% and 48.48%, respectively, and its measuring accuracy becomes equivalent to that at the constant temperature. The experimental results verify the feasibility and effectiveness of the model developed for indirect compensation of temperature error. [ABSTRACT FROM AUTHOR]

Cervical cancer is among the most prevalent forms of cancer worldwide. C-C chemokine receptor type 5 (CCR5) is hypothesized to be a key functional protein involved in tumorigenesis. However, the role of CCR5 in cervical cancer remains unclear. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were used to evaluate the mRNA and protein expression levels of CCR5 in human cervical carcinoma tissues. Furthermore, a small interfering RNA was employed to knockdown CCR5 in HeLa and C33A cells. MTT, colony formation and Transwell assays were performed to determine the effects of this knockdown on cell viability, proliferation and invasion. In addition, micro RNA (miR)-107 was identified as a potential candidate regulator of CCR5 using miR prediction algorithms, and the effects of miR-107 and its antisense miR on CCR5 mRNA expression were determined. The results of the present study indicated that CCR5 is overexpressed in human cervical cancer tissues compared with adjacent normal tissues, and its downregulation inhibits cervical cancer cell growth and proliferation. Furthermore, the downregulation of CCR5 appears to suppress cervical cancer cell invasion. Finally, the tumor suppressor miR-107 was able to directly target CCR5 and inhibit its expression. These results suggest that the upregulation of CCR5, which is inhibited by miR-107, may play a carcinogenic role in cervical cancer and could provide a novel therapeutic target in the future. [ABSTRACT FROM AUTHOR]

This paper focuses on the problem of asymptotic stabilization for a class of discrete-time multiple time-delayed uncertain linear systems with input constraints. Then, based on the predictive control principle of receding horizon optimization, a delayed state dependent quadratic function is considered for incorporating MPC problem formulation. By developing a memory state feedback controller, the information of the delayed plant states can be taken into full consideration. The MPC problem is formulated to minimize the upper bound of infinite horizon cost that satisfies the sufficient conditions. Then, based on the Lyapunov-Krasovskii function, a delay-dependent sufficient condition in terms of linear matrix inequality (LMI) can be derived to design a robustMPC algorithm. Finally, the digital simulation results prove availability of the proposed method. [ABSTRACT FROM AUTHOR]

The nickel-catalyzed reductive coupling of alkynes and imines with Et2Zn as a reductant by using electron-rich phosphine ligands has been developed, affording various allylic amines with high yields and excellent chemoselectivities. Chiral induction was also achieved in this reductive coupling reaction when a nickel catalyst containing a chiral spiro phosphine ligand was used. [ABSTRACT FROM AUTHOR]

Background: CD4+ T cells are critical effectors of anti-tumor immunity, but how tumor cells influence CD4+ T cell effector function is not fully understood. Tumor cell-released autophagosomes (TRAPs) are being recognized as critical modulators of host anti-tumor immunity during tumor progression. Here, we explored the mechanistic aspects of TRAPs in the modulation of CD4+ T cells in the tumor microenvironment. Methods: TRAPs isolated from tumor cell lines and pleural effusions or ascites of cancer patients were incubated with CD4+ T cells to examine the function and mechanism of TRAPs in CD4+ T cell differentiation and function. TRAPs-elicited CD4+ T cells were tested for their suppression of effector T cell function, induction of regulatory B cells, and promotion of tumorigenesis and metastasis in a mouse model. Results: Heat shock protein 90α (HSP90α) on the surface of TRAPs from malignant effusions of cancer patients and tumor cell lines stimulated CD4+ T cell production of IL-6 via a TLR2--MyD88--NF-κB signal cascade. TRAPs-induced autocrine IL-6 further promoted CD4+ T cells secretion of IL-10 and IL-21 via STAT3. Notably, TRAPs-elicited CD4+ T cells inhibited CD4+ and CD8+ effector T cell function in an IL-6- and IL-10-dependent manner and induced IL-10- producing regulatory B cells (Bregs) via IL-6, IL-10 and IL-21, thereby promoting tumor growth and metastasis. Consistently, inhibition of tumor autophagosome formation or IL-6 secretion by CD4+ T cells markedly retarded tumor growth. Furthermore, B cell or CD4+ T cell depletion impeded tumor growth by increasing effector T cell function. Conclusions: HSP90α on the surface of TRAPs programs the immunosuppressive functions of CD4+ T cells to promote tumor growth and metastasis. TRAPs or their membrane-bound HSP90α represent important therapeutic targets to reverse cancer-associated immunosuppression and improve immunotherapy. [ABSTRACT FROM AUTHOR]

Background: Approximately, one-third of adult patients with acute myeloid leukemia (AML) are refractory to initial induction chemotherapy and relapse occurs in most patients who achieve remission. This study evaluates the efficacy of decitabine in the management of refractory or relapsed AML. Methods: After literature search in electronic databases (Google Scholar, Embase, Ovid, and PubMed) studies were selected by following pre-determined eligibility criteria. Random-effects meta-analyses were performed to achieve effect sizes of complete remission (CR) rate, response rate (RR), and median survival after therapy. Subgroup analyses were performed with regards to use of decitabine with either epigenetics-based therapy, molecular therapy or chemotherapy. Results: Twenty studies were included (310 patients; age 55.1 years [95% confidence interval (CI): 43.8, 66.4]; 57% [52%, 63%] males). Overall RR was 46.1% [95% CI: 36.1%, 56.1%]. Overall CR rate was 23.5% [95% CI: 22.1%, 24.9%] but was 14.85% [95% CI: 3.8%, 25.9%] for decitabine with epigenetics-based therapies, 15.4% [95% CI: 6.7%, 24.0%] for decitabine with immunotherapy or molecular therapy, 34.8% [95% CI: 18.7%, 50.9%] for decitabine with chemotherapy, and 37.5% [36.4%, 38.7%] for decitabine with chemotherapy and molecular therapy. Median survival was 7.2 months [95% CI: 5.17, 9.3]. Major adverse events were neutropenia, nausea/vomiting, infections, fatigue, febrile neutropenia, diarrhea, thrombocytopenia, anemia, anorexia, leukopenia, hemorrhage, and hyperglycemia. Conclusion: Decitabine in combination with chemotherapy or molecular therapy has shown efficacious properties in refractory or relapsed AML patients. [ABSTRACT FROM AUTHOR]

The recently proposed method of our research group named as directional Lyapunov exponents (DLEs) is presented. Then, DLEs are used to analyze the eigenstructure of the output phase space around the equilibrium points. Finally, the impacts of the superlattice parameter changes on the characteristics of the output chaotic signal are analyzed. The experimental results show that parameter changes of the superlattice will affect the eigenstructure around the equilibrium points in the output phase space, and DLEs are sensitive to these changes. [ABSTRACT FROM AUTHOR]

A new isatin N,N'-cyclic azomethine imine 1,3-dipole was devised, and an unusual Michael addition with β-nitrostyrene catalyzed by tributylamine under mild conditions has been developed. The new reaction featured the C3 umpolung of oxindole and an unusual formation of double bond. Notably, this new synthon performed as a donor rather than an acceptor. This protocol provided a promising method for the preparation of various 3-aminooxindoles with good yields in moderate diastereoselectivities. [ABSTRACT FROM AUTHOR]

An unusual and highly effective asymmetric annulation of nitrosoarenes with hydroxymaleimides catalyzed by a chiral bifunctional amine squaramide catalyst has been disclosed. A wide range of highly fused chiral N-hydroxyindolines with two consecutive quaternary stereocenters and multifunctional groups were directly and effectively prepared in excellent yields (up to >99%) with complete regioselective cyclization and excellent stereoselectivities (up to >99:1 dr and >99% ee). The efficiency and potentials of the new reaction and the target chiral entities were well demonstrated by delicate transformations into a series of new chiral indolines. [ABSTRACT FROM AUTHOR]

A new isatin N,N'-cyclic azomethine imine synthon was devised, and an unexpected abnormal [3 + 2]-cycloaddition with maleimide catalyzed by 1,4-diazabicyclo[2.2.2]octane (DABCO) has been disclosed. A variety of tricyclic spiropyrrolidine oxindoles bearing a dinitrogen heterocycle and succinimide scaffold were obtained in excellent yields (up to 96%) and diastereoselectivities (up to 97:3) under mild conditions. [ABSTRACT FROM AUTHOR]

The first nickel-catalyzed intermolecular hydroacylation reaction of alkenes with simple aldehydes has been developed. This reaction offers a new approach to the selective preparation of branched ketones in high yields (up to 99%) and branched selectivities (up to 99:l). Experimental data provide evidence for reversible formation of acyl--nickel--alkyl intermediate, and DFT calculations show that the aldehyde C--H bond transfer to a coordinated alkene without oxidative addition is involved. The origin of the reactivity and regioselectivity of this reaction was also investigated computationally, which are consistent with experimental observations. [ABSTRACT FROM AUTHOR]

The article discusses the development of highly enantioselective hydrogenation of simple N-unprotected enamines catalyzed by a Rh(I) complex of chiral spiro phosphonite ligand (S)-1c, which provided a straightforward method for the synthesis of chiral tertiary amines with great ee values. Chiral amines are an important class of compounds in organic and pharmaceutical synthesis. The catalytic asymmetric hydrogenation of N,N-diakylenamines is one of the most straightforward accesses to the optically active tertiary 1,2-diarylethanamines.

Background Anterior thoracoscopic release combined with posterior correction is a common surgery to treat idiopathic scoliosis (IS). However, whether it has detrimental effects on pulmonary function is still unknown. Aim The aim of the study is to evaluate the effect of anterior thoracoscopic release combined with posterior correction on the pulmonary function. Materials and Methods A retrospective study of 28 (12male, 16 female) patients with IS undergoing anterior thoracoscopic release combined with posterior correction from 2009 to 2011 was performed. The radiographic and pulmonary function evaluations were performed preoperatively and at 24 months postoperatively. Results The average coronal Cobb angle was corrected from 88.36 ± 25.6 degrees to 49.8 ± 11.8 degrees, and average sagittal Cobb angle was corrected from 57.5 ± 17.2 degrees to 26.3 ± 4.7 degrees. The measured forced vital capacity (FVC) and total lung capacity (TLC) were significantly increased at 2 years postoperatively (3.21 ± 1.18 versus 2.47 ± 0.33; 4.32 ± 1.41 versus 3.68 ± 0.36; p < 0.01). However, no significant difference in the FVC% and TLC% was observed. The functional residual capacity percentage was 109.87 ± 14.87 preoperatively and increased to 118.56 ± 34.34 at 2 years postoperatively (p < 0.05). Both the measured residual volume (RV) and RV% were reduced postoperatively (p < 0.05). The maximum ventilatory volume percentage improved significantly (107.38 ± 39.22 versus 77.46 ± 12.37, p < 0.05). In addition, total airway resistance, inhaled airway resistance, and exhaled airway resistance were all decreased significantly. Conclusion Anterior thoracoscopic release combined with posterior correction has proved to be a safe surgical technique that results in minor pulmonary function impairment. [ABSTRACT FROM AUTHOR]

Background: Our previous studies have demonstrated that autophagosome-enriched vaccine (named DRibbles: DRiPs-containing blebs) induce a potent anti-tumor efficacy in different murine tumor models, in which DRibble-containing ubiquitinated proteins are efficient tumor-specific antigen source for the cross-presentation after being loaded onto dendritic cells. In this study, we sought to detect whether ubiquitinated proteins enriched from tumor cells could be used directly as a novel cancer vaccine. Methods: The ubiquitin binding protein Vx3(A7) was used to isolate ubiquitinated proteins from EL4 and B16-F10 tumor cells after blocking their proteasomal degradation pathway. C57BL/6 mice were vaccinated with different doses of Ub-enriched proteins via inguinal lymph nodes or subcutaneous injection and with DRibbles, Ub-depleted proteins and whole cell lysate as comparison groups, respectively. The lymphocytes from the vaccinated mice were re-stimulated with inactivated tumor cells and the levels of IFN-γ in the supernatant were detected by ELISA. Anti-tumor efficacy of Ub-enriched proteins vaccine was evaluated by monitoring tumor growth in established tumor mice models. Graphpad Prism 5.0 was used for all statistical analysis. Results: We found that after stimulation with inactivated tumor cells, the lymphocytes from the Ub-enriched proteins-vaccinated mice secreted high level of IFN-γ in dose dependent manner, in which the priming vaccination via inguinal lymph nodes injection induced higher IFN-γ level than that via subcutaneous injection. Moreover, the level of secreted IFN-γ in the Ub-enriched proteins group was markedly higher than that in the whole cell lysate and Ub-depleted proteins. Interestingly, the lymphocytes from mice vaccinated with Ub-enriched proteins, but not Ub-depleted proteins and whole cell lysates, isolated from EL4 or B16-F10 tumor cells also produced an obvious level of IFN-γ when stimulated alternately with inactivated B16-F10 or EL4 tumor cells. Furthermore, Ub-enriched proteins vaccine showed a significant inhibitory effect on in vivo growth of homologous tumor, as well as allogeneic tumor, compared with Ub-depleted proteins and tumor cell lysate. Tumor growth was regressed after three times of vaccination with Ub-enriched proteins in contrast to other groups. Conclusion: These results indicated that Ub-enriched proteins isolated from tumor cells may have a potential as a potent vaccine for immunotherapy against cancer. [ABSTRACT FROM AUTHOR]

A new organocatalytic asymmetric domino Michael-alkylation reaction of methyleneindolinones and γ-halogenated-β-ketoesters is described. A variety of spiro-cyclopentanoneoxindoles were obtained in high yields (up to 96%), good diastereoselectivities (up to 12:1 dr) and excellent enantioselectivities (up to >99% ee) via a-alkylation. Interestingly, O-alkylated products with tetronic acid motifs could be obtained by tuning the N-protecting groups on methyleneindolinones with excellent enantioselectivities (up to > 99% ee). [ABSTRACT FROM AUTHOR]

Previously, we have documented that isolated autophagosomes from tumor cells could efficiently cross-prime tumor-reactive naïve T cells and mediate tumor regression in preclinical mouse models. However, the effect of tumor-derived autophagosomes, here we refer as to DRibbles, on B cells has not been studied so far. At present study, we found that DRibbles generated from a murine hepatoma cell line Hep1-6, induced B-cell activation after intravenous injection into mice. B-cell populations were significantly expanded and the production of Hep1-6 tumor-specific antibodies was successfully induced. Moreover, in vitro studies showed that DRibbles could induce more efficient B-cell proliferation and activation, antibody production, and cytokine secretion than whole tumor cell lysates. Notably, we found that B-cell activation required proteins but not DNA in the DRibbles. We further showed that B cells could capture DRibbles and present antigens in the DRibbles to directly induce T cell activation. Furthermore, we found that B-cell activation, antibody production, cytokine secretion and antigen cross-presentation were TLR2-MyD88 pathway dependent. Taken together, the present studies demonstrated that tumor-derived autophagosomes (DRibbles) efficiently induced B cells activation, antibody production, cytokine secretion and antigen cross-presentation mainly depending on their protein component via TLR2/MyD88 dependent manner. [ABSTRACT FROM AUTHOR]

The direct asymmetric vinylogous Mannich reaction of 3,4-dihalofuran-2(5H)-one with aldimine catalyzed by quinine was first reported, and γ-butenolides have been obtained in excellent yield (up to 98%) and enantioselectivities (up to 95% ee). The synthetic applications of this protocol are demonstrated in the preparations of γ-substituted amino butyrolactones and vicinal amino alcohols. [ABSTRACT FROM AUTHOR]

A highly diastereoselective and enantioselective Michael addition of α-substituted isocyanoacetates with maleimides catalyzed by bifunctional tertiary amine thioureas has been developed. Various chiral succinimide derivatives bearing adjacent quaternary and tertiary stereocenters were prepared in excellent yields (up to 98%), diastereoselectivities (up to 99:1), and enantioselectivities (up to 98% ee). The synthetic utility of chiral succinimide derivatives is also demonstrated in the preparation of h5-HT1d receptor agonist motifs. [ABSTRACT FROM AUTHOR]

A catalytic hydrovinylation of N-acetylenamines with ethylene is reported. This new hydrovinylation reaction is catalyzed by a ruthenium hydride complex, RuHCl(CO)(PCy3)2, providing a series of N-acetylamines with a quaternary carbon center with up to 99% yield. [ABSTRACT FROM AUTHOR]

A series of secondary amine-thiourea catalysts 1a-1d derived from L-proline and chiral diamine were prepared and successfully applied to the Michael addition of acetone to trans-nitroalkenes in excellent yields (up to 99%) and enantioselectivities (44-91% ee). [ABSTRACT FROM AUTHOR]

A highly efficient enantio- and diastereoselective synthesis of chiral cis-β-N-alkyl/arylamino cyclic alcohols has been realized by asymmetric hydrogenation of racemic α-amino cyclic ketones via DKR catalyzed by [RuCl2((S)-Xyl-SDP)((R,R)-DPEN)]. The enantioselectivities of the reaction were up to 99.9% ee with 99:1 cis-selectivities. A practical catalytic asymmetric synthesis of all four isomers of conhydrine was also developed. [ABSTRACT FROM AUTHOR]

Several examples have shown that C3d3, when fused to a corresponding antigen, had a strong adjuvant effect on certain specific antibody production. In a previous study, we attempted to prove that this was the case of the human chorionic gonadotrophin β chain (hCGβ)-induced immunity following DNA vaccination. However, we found that C3d3 when fused to hCGβ inhibited rather than enhanced the antigen-specific immune response. In the present study, using hCGβ DNA vaccine preparations, we demonstrated that C3d3 inhibited the antigen-specific humoral antibody response and several other immune responses, such as the hCGβ specific lymphoproliferation. Such inhibitory effects of C3d3 were not related to the expression level of the target protein, the gender of the test mice, or the vector used. Contrastingly, C3d3 fused with the envelope protein of hepatitis B virus (PreS2/S) used as a control system resulted in the enhancement of both humoral and cell-mediated antigen-specific immune responses against HBV-preS2/S, which was consistent with other groups’ adjuvant-effect findings. We further showed that the mechanisms involved in the inhibitory effect of C3d3 might be possible due to impairing the function of antigen presenting B lymphocytes and reducing the expression of transcription factors (T-bet and GATA-3) and cytokine IL-4. Collectively, unlike its usual expected adjuvant function, the fusion of C3d3 with the tumor-associated antigen hCGβ was found to inhibit both humoral and cell-mediated antigen-specific immune responses. These findings indicate that research concerning tumor immune escapes and vaccine designs require further extensive attention. [ABSTRACT FROM AUTHOR]

The RuII complexes of SDP and DPEN combined with t-BuOK in 2-propanol formed a very effective catalyst for the hydrogenation of simple aromatic ketones with high activity and enantioselectivity. The racemic α-arylcycloalkanones can also be hydrogenated by this system, providing α-arylcycloalkanols in excellent cis/trans stereoselectivity (>99:1) and enantioselectivity (up to 99.9%) for the cis isomer. In the study of the effect of the alkali metal cation in the hydrogenation of acetophenone using RuC12(Tol-SDP)(DPEN) and RuCl2(Xyl-SDP)(DPEN) catalysts, we found that t-BuONa provided a faster reaction than t-BuOK, which indicated that the sterically hindered diphosphine ligands preferred the base with the smaller metal cation. [ABSTRACT FROM AUTHOR]

A series of simple chiral primary amino acids were first successfully applied to promote the enantioselective α-amination of branched aldehydes with azadicarboxylates and the desired adducts bearing quaternary stereogenic centers were obtained in excellent yields (up to 99%) and enantioselectivities (up to 97% ee). [ABSTRACT FROM AUTHOR]

An efficient Michael-ketone aldol-dehydration domino reaction has been developed to afford spiro[cyclohex-2-enone-oxindole] motifs with high yields (up to 99%), excellent diastereoselectivities (dr > 20 : 1) and enantioselectivities (up to 96% ee). [ABSTRACT FROM AUTHOR]

• The present experiments aimed to study risk-based decisions between options of equivalent expected value in rats. • Stimulation of α2-adrenergic receptors by dexmedetomidine reduced risky choices. • Blocking α2-adrenergic receptors by atipamezole reduced risky choices. • Stimulation of 5-HT2A receptors by DOI increased risk-taking behavior in the risk-prefer group. Risk perception is an important factor that may mediate risk-based decision-making processes regulated by noradrenergic (NA) and serotonergic (5-HT) systems. Most risk-based decision-making models involve complex factors, such as risk perception or reward value, such that the final decision is the result of the interactions among these factors. However, the contribution of risk perception per se in risk decisions has remained unclear. Therefore, in the present study, we made some modifications to the classical probabilistic discounting task (PDT) to focus on the impact of risk perception and noradrenergic/serotonergic systems on decision-making behavior. Meanwhile, we conducted an elevated plus-maze (EPM) test to detect the correlation between anxiety and choice behavior. In the current study, rats had to choose between a "certain" lever that delivered a certain number of pellets and a "risky" lever that delivered eight pellets in a probabilistic manner (descending: 50%, 25%, 12.5% or ascending 12.5%, 25%, 50% of the time). The long-term rewarding values of the two levers were always identical in each block within each session. According to their baseline performances in choosing the risky lever, rats were divided into the risk-prefer group and risk-averse group. The results showed that there was a significant correlation between open arm time in EPM and risky choice for both descending order and ascending order, indicating that highly anxious rats more often preferred the safe option under risk. Pharmacological stimulation of α2-adrenergic receptors via dexmedetomidine (0.01 mg/kg) decreased the preference of probabilistic rewards in the risk-prefer group, while blocking α2 receptors by atipamezole (0.3 mg/kg) also reduced risky choices. The NA reuptake inhibitor, atomoxetine, increased the preference for risky choices in the risk-prefer group, the effect of which was attained via multiple superimposed doses. Administration of the 5-HT 2A receptor agonist, DOI (0.1 mg/kg), increased risk-taking behavior in the risk-prefer group. Taken together, these results suggest that NA may be more inclined to process negative information such as loss or uncertainty in the regulation of risk-related decision making, whereas 5-HT may function primarily to increase risk-taking behavior. Our findings may help to further elucidate how noradrenergic and serotonergic systems differentially affect individuals with different risk preferences in terms of regulating risk perception in risk-related decision making. [ABSTRACT FROM AUTHOR]

Novel monodentate chiral spiro phosphoramidite ligands have been readily synthesized in good yields from enantiomerically pure 1,1'-spirobiindane-7,7'-diol. The new ligands were highly efficient in the copper-catalyzed conjugate addition of Et[sub 2]Zn to enones with up to 98% enantiomeric excess. [ABSTRACT FROM AUTHOR]

Superlattices in chaotic state can be used as a key part of a true random number generator. The chaotic characteristics of the signal generated in the superlattice are mostly affected by the parameters of the superlattice and the applied voltage, while the latter is easier to adjust. In this paper, the model of the superlattice is first established. Then, based on this model, the chaotic characteristics of the generated signal are studied under different voltages. The results demonstrate that the onset of chaos in the superlattice is typically accompanied by the mergence of multistability, and there are voltage intervals in each of which the generated signal is chaotic. [ABSTRACT FROM AUTHOR]

We present a detailed study of a superjunction (SJ) nanoscale partially narrow mesa (PNM) insulated gate bipolar transistor (IGBT) structure. This structure is created by combining the nanoscale PNM structure and the SJ structure together. It demonstrates an ultra-low saturation voltage (Vce(sat)) and low turn-off loss (Eoff) while maintaining other device parameters. Compared with the conventional 1.2 kV trench IGBT, our simulation result shows that the Vce(sat) of this structure decreases to 0.94 V, which is close to the theoretical limit of 1.2 kV IGBT. Meanwhile, the fall time decreases from 109.7 ns to 12 ns and the Eoff is down to only 37% of that of the conventional structure. The superior tradeoff characteristic between Vce(sat) and Eoff is presented owing to the nanometer level mesa width and SJ structure. Moreover, the short circuit degeneration phenomenon in the very narrow mesa structure due to the collector-induced barriers lowering (CIBL) effect is not observed in this structure. Thus, enough short circuit ability can be achieved by using wide, floating P-well technique. Based on these structure advantages, the SJ-PNM-IGBT with nanoscale mesa width indicates a potentially superior overall performance towards the IGBT parameter limit. [ABSTRACT FROM AUTHOR]

The article discusses the enantioselective and diastereoselective synthesis of chiral amino alcohols obtained through α -amino aliphatic ketone ruthenium-catalyzed asymmetric hydrogenation. It notes that the asymmetric hydrogenation serves as one of the most elegant approaches to chiral 1,2-amino alcohols. Experiment shows that the substrate with bulkier dialkylamino group gave lower diastereoselectivity which obstructed the hydrogen-bonding formation.

The article discusses the highly enantio selective insertion of carbenoids into oxygen-hydrogen bonds phenols, which is considered an effective approach to chiral α-aryloxycarboxylic esters. It is inferred that the enatioselectivity waned when the Cu/biazaferrocene catalyst was applied to phenol substrates. Moreover, the optically active α-arloxypropionates and the related acids were synthesized conveniently using the copper complexes of chiral spiro bisoxazolines as crystalysts.

The article presents a study on the nickel-catalyzed asymmetric reductive coupling of 1, 3-dienes and aldehydes, which offers a useful method for preparing chiral bishomoallylic alcohols in excellent diastereoselectivity and enantioselectivity. The study examines various chiro spiro monophosphorus ligands in the nickel-catalyzed coupling reaction to produced chiral bishomoallylic alcohols. Results reveal that by using nickel complexes with a reducing agent, the high yields alcohol is obtained.