Copper-Catalyzed Enantioconvergent Radical C(sp)-N Cross-Coupling to Access Chiral α-Amino-β-lactams.

A copper-catalyzed enantioconvergent radical C(sp)-N cross-coupling of racemic tertiary α-bromo-β-lactams with aromatic amines is developed under mild thermal reaction conditions. The use of a sterically demanded oxazoline-derived sulfonamide N,N,N-ligand is crucial for the reaction initiation and effective enantio-discrimination of the azetidinone-derived cyclic alkyl radicals. The strategy provides an attractive approach to access chiral α-amino-β-lactams, an important structural motif in many biologically active molecules.

Copper-Catalyzed Enantioconvergent Radical -Alkylation of Diverse (Hetero)aromatic Amines.

The 3d transition metal-catalyzed enantioconvergent radical cross-coupling provides a powerful tool for chiral molecule synthesis. In the classic mechanism, the bond formation relies on the interaction between nucleophile-sequestered metal complexes and radicals, limiting the nucleophile scope to sterically uncongested ones. The coupling of sterically congested nucleophiles poses a significant challenge due to difficulties in transmetalation, restricting the reaction generality.

Copper-Catalyzed Enantioconvergent Radical C(sp)-N Cross-Coupling of Activated Racemic Alkyl Halides with (Hetero)aromatic Amines under Ambient Conditions.

The enantioconvergent C(sp)-N cross-coupling of racemic alkyl halides with (hetero)aromatic amines represents an ideal means to afford enantioenriched -alkyl (hetero)aromatic amines yet has remained unexplored due to the catalyst poisoning specifically for strong-coordinating heteroaromatic amines. Here, we demonstrate a copper-catalyzed enantioconvergent radical C(sp)-N cross-coupling of activated racemic alkyl halides with (hetero)aromatic amines under ambient conditions. The key to success is the judicious selection of appropriate multidentate anionic ligands through readily fine-tuning both electronic and steric properties for the formation of a stable and rigid chelating Cu complex.

Enantioconvergent Cu-catalysed N-alkylation of aliphatic amines.

Chiral amines are commonly used in the pharmaceutical and agrochemical industries. The strong demand for unnatural chiral amines has driven the development of catalytic asymmetric methods. Although the N-alkylation of aliphatic amines with alkyl halides has been widely adopted for over 100 years, catalyst poisoning and unfettered reactivity have been preventing the development of a catalyst-controlled enantioselective version.

Effects of Acute Interval Exercise on Arterial Stiffness and Cardiovascular Autonomic Regulatory Responses: A Narrative Review of Potential Impacts of Aging.

The physiological changes associated with aging deleteriously impact cardiovascular function and regulation and therefore increase the risk of developing cardiovascular disease. There is substantial evidence that changes in the autonomic nervous system and arterial stiffness play an important role in the development of cardiovascular disease during the aging process. Exercise is known to be effective in improving autonomic regulation and arterial vascular compliance, but differences in the type and intensity of exercise can have varying degrees of impact on vascular regulatory responses and autonomic function.

Lithium-induced overexpression of β-catenin delays murine palatal shelf elevation by Cdc-42 mediated F-actin remodeling in mesenchymal cells.

Background: Lithium chloride (LiCl) is widely used for the treatment of manic and other psychotic disorders, but the administration of lithium can result in several congenital defects in the fetus, including cleft palate (Meng, Wang, Torensma, Jw & Bian, 2015) (Szabo, 1970). However, the mechanism of Lithium's action as a developmental toxicant in palatogenesis is not well known.

Methods: In this study, hematoxylin-eosin and immunofluorescence staining were employed to evaluate the phenotypes and the expression of related markers in the LiCl-treated mice model.

LAPTM5 is transactivated by RUNX2 and involved in RANKL trafficking in osteoblastic cells.

The present study aimed to investigate the role of lysosomal‑associated transmembrane protein 5 (LAPTM5) in osteoclast differentiation induced by osteoblasts. The results demonstrated that the expression levels of LAPTM5 were downregulated following runt‑related transcription factor 2 (RUNX2) silencing and upregulated following RUNX2 overexpression in ST2 cells. Chromatin immunoprecipitation analysis identified the binding of RUNX2 to the LAPTM5 promoter at the ‑1176 to ‑1171 position.

Emission Lifetimes of a Fluorescent Dye under Shock Compression.

The emission lifetimes of rhodamine 6G (R6G) were measured under shock compression to 9.1 GPa, with the dual intents of better understanding molecular photophysics in extreme environments and assessing the usefulness of fluorescence lifetime microscopy to measure spatially dependent pressure distributions in shocked microstructured media. R6G was studied as free dye dissolved in poly(methyl methacrylate) (PMMA), or dye encapsulated in silica microparticles suspended in PMMA.

[Application of wavenumber-linear scaling to the calculated Raman frequencies of polyenes and carotenoids].

Raman spectra of two typical carotenoids (beta-carotene and lutein) and some short (n = 2-5) polyenes were calculated using density functional theory. The wavenumber-linear scaling (WLS) and other frequency scaling methods were used to calibrate the calculated frequencies. It was found that the most commonly used uniform scaling (UFS) method can only calibrate several individual frequencies perfectly, and the systematic result of this method is not very good.

Relationship between respiratory viral load and lung lesion severity: a study in 24 cases of pandemic H1N1 2009 influenza A pneumonia.

Objective: To investigate the relationship between respiratory viral load and lung lesion severity of patients with pandemic H1N1 2009 influenza A pneumonia.

Study Design: Cross-sectional observation study.

Methods: 24 consecutive H1N1 influenza patients with viral pneumonia (13 males, 11 females, mean age: 17.

[The genetical evolution of the full length genes of 5 EV 71 strains from 5 Shenzhen patients with hand-food-mouth disease associated with EV71 infection].

Objective: To investigate the characteristics of molecular epidemiology and molecular evolution of 5 EV 71 (enterovirus 71, EV71) strains from 5 Shenzhen patients with hand-food-mouth disease associated with EV 71 infection.

Methods: 5 EV 71 strains were isolated, and sequenced to analyzed the full length gene sequences in order to compare nucleotide and amino acid homology with other EV71 strains from other regions and countries as well as previous strains across the world through bioinformatics software.

Results: 5 strains of EV 71 belonged to sub-genotype C4 by analysis of nucleotide sequences of VP1 and VP4 of EV 71.

[Study on characteristics of cellular-mediated immune responses of novel H1N1 influenza A patients with pneumonia].

Objective: To investigate the phenotype, frequency and function of CD4+ T cell subsets and the relevant cytokines, as well as the relationship between these cells and appearance of pneumonia of novel (H1N1) influenza A patients.

Methods: 68 healthy people, 53 confirmed novel A(H1N1) influenza patients without pneumonia and 16 confirmed severe novel A (H1N1) influenza patients with pneumonia were enrolled in this study. Viral load in nasopharyngeal swabs specimens was measured by real time PCR assay.

Measurement of infrared level lifetime by upconversion luminescence.

Based on repetition frequency-dependent excited state absorption (ESA) upconversion (UC) luminescence, a method to measure the lifetime of an IR intermediate level is proposed so long as ESA UC luminescence can occur in the rare earth ions. The feasibility of this idea is demonstrated via a theoretical simulation. A Er(3+):LiNbO₃ crystal ESA UC luminescence under femtosecond laser excitation is used to illustrate this measurement method, and the obtained 1.

Effect of end groups on the raman spectra of lycopene and β-carotene under high pressure.

The Raman spectra of all-trans-lycopene in n-hexane were measured under high pressure, and the results compared with those of β-carotene. The different pressure effects on Raman spectra are analyzed taking into account the different structures of lycopene and β-carotene molecules. It is concluded that: (a) the vibronic coupling between the S₁ and S₀ states of β-carotene is stronger than that of lycopene, (b) the diabatic frequency increment of the ν₁ mode is more susceptible to pressure than that of the ν₂ mode for lycopene, and (c) β-rings rotation can relieve the pressure effect on the C=C bond length in β-carotene.

[Integration sites in HCC biopsy].

Objective: To compare the performance of Inverse-PCR, Alu-PCR and Cassette-ligation-mediated PCR (CLM-PCR) in HBV DNA integration sites identification.

Methods: One HCC biopsy was obtained from surgically resected sample. The patient was positive for serum hepatitis B surface antigen (HBsAg).

[The relationship between chest CT findings and viral load in patients with novel influenza A (H1N1)].

Objective: To evaluate the value of chest CT findings and dynamic changes of viral load in patients with novel influenza A (H1N1) infection in clinical diagnosis, differential diagnosis and treatment.

Methods: Fifty-one patients with confirmed novel influenza A (H1N1) according to the diagnostic criteria of the Ministry of Health, received chest X-ray, CT scans (HRCT) and viral load tests in our hospital from May to December of 2009. Based on whether there were signs of pneumonia in CT imaging, the patients were divided into a pneumonia group (n = 31) and a non-pneumonia group (n = 20).

Structures and magnetic properties of electroless Ni multilayers on Fe/Si substrate.

Nanosized single and multiple layers of electroless Ni films were deposited on Fe film. The multilayer films consisting of a Fe/(Ni1 Ni2)n structure, where Ni1 and Ni2 denote various electroless Ni films deposited in plating baths with different pH values, and n denotes layer numbers and equals to 2, 4, 8, and 16, were formed by alternately changing the pH value of plating baths under controlled deposition time during the deposition process. The ensuing results showed that the boundaries between films are almost even.

[To investigate pathogen of hand, foot and mouth disease in Shenzhen in 2008].

Objective: To investigate EV71 and CA16 pathogen of HFMD in Shenzhen in 2008, and to provide the evidence for the prevention and treatment HFMD.

Method: Using RT-PCR technology to detect the EV71 and CoxA16 genes of 307 samples HFMD; sequencing the purified PCR products from 14 samples. Using ClustalW2 online analysis software for sequence and phylogenetic analysis of enterovirus 71.

[Expression of a single-chain trimer of MHC restricted HBsAg CTL epitope using adenovirus vector containing GFP-report gene].

Objective: To generate a recombinant Adenovirus encoding a GFP (green fluorescent protein)-report gene and a single-chain trimer of MHC restricted HBsAg CTL epitope.

Methods: An oligonucleotide encoding H-2L(d) restricted HBsAg CTL epitope was synthesized and fused with H-2L(d) DNA molecule to construct the eukaryotic expression vector carrying the HBsAg-SCT gene. The HBsAg-SCT gene was subcloned into a GFP adenovirus expression vector,which was transfected into Ad293 cells for packaging and amplification of recombinant adenovirus encoding HBsAg-SCT.

[Effects of perchlorate on growth and chlorophyll fluorescence parameters of Alternanthera philoxeroides].

Perchlorate is a new emerging persistent pollutant, while no studies about its effects on plants have been reported both home and abroad. In order to explore the effects of perchlorate on growth and physiology of aquatic plant, Alternanthera philoxeroides were treated by 1/20 Hoagland nutrient solution with different concentrations (0, 1, 5, 20, 100, 500 mg/L) of ClO4- under the controlled conditions. The results showed as follow.

[Expression of recombinant VP1 protein of enterovirus 71 and development of serological assay for detection of EV71 infection].

Objective: To obtain a recombinant purified Enterovirus 71 VPI protein and establishment of an early, rapid and accurate serological ELISA (enzyme-linked immunosorbent assay) for detection of EV71 infection.

Methods: VP1 gene was amplified by PCR and clonel into pET-21b (+) vector, the positive recombinant plasmid were transformed into E. coli BI21(DE3), and was induced with IPTG, the recombinant protein by SDS-PAGE and Western Blot assays.

[Study of the clinical and laboratory features of hand-foot-mouth disease].

Objective: To study the clinical and laboratory features of the mild and severe hand-foot-mouth diseases (HFMD) in Shenzhen in 2008.

Methods: 145 cases were observed in East-Lake Hospital and Shenzhen Children's Hospital. Of the 145 cases, 124 mild cases and 21 severe cases were involved.

[Expression of Mycobacterium tuberculosis early secretory antigenic target-6 protein and its application in detection of Mycobacterium tuberculosis antigen-specific interferon-gamma response].

Objective: To obtain the purified early secretory antigenic target-6 (ESAT-6) protein and to evaluate its application in detection of Mycobacterium tuberculosis antigen-specific interferon-gamma (IFN-gamma) response.

Methods: ESAT-6 protein was expressed by genetic engineering. The antigen specificity and reactivity of ESAT-6 were evaluated by Western blot.

Red upconversion emission in LiNbO3 codoped with Er3+ and Eu3+.

Red upconversion (UC) emission at 626 nm is obtained from a LiNbO(3) crystal codoped with Er(3+) and Eu(3+) under 800 nm femtosecond laser excitation. Energy transfer from ((2)H(11/2,),(4) S(3/2)) levels of Er(3+), which are excited by excited state absorption, to (5)D(1) of Eu(3+) followed by rapidly relaxing to (5)D(0) nonradiatively leads to this red UC emission. The energy transfer efficiency and Er-Eu transfer microparameter of approximately 30% is obtained in LiNbO(3):Er(3+)(1.