Responses of leaf traits to altitude in Quercus aquifolioides and Sorbus rehderiana on the eastern edge of the Qinghai-Tibet Plateau, China.

As the most senstitive plant organs to environmental changes, leaves serve as crucial indicators of plant survival strategies. We measured the morphology, anatomical traits, gas exchange parameters, and chlorophyll fluorescence parameters of Quercus aquifolioides (evergreen broad-leaved) and Sorbus rehderiana (deciduous broad-leaved) at altitudes of 2600, 2800, 3000, 3200 and 3400 m on the eastern edge of the Qinghai-Tibet Plateau, China. We explored the similarity and difference in their responses to altitude change and the ecological adaptation strategy. The results showed that as the altitude increased, leaf dry matter content of Q. aquifolioides decreased, that of S. rehderiana increased, leaf size for both species gradually decreased, and the palisade coefficient of Q. aquifolioides showed a decreasing trend, contrasting with the increasing trend in S. rehderiana. As the altitude increased, the thickness of leaves, palisade tissue, spongy tissue, upper epidermis, and lower epidermis of both species increased significantly, with the increment of 22.4%, 4.9%, 45.1%, 23.3%, 19.6%, and 28.2%, 46.9%, 8.9%, 25.9%, 20.8% at altitude of 3400 m, respectively, compared with the altitude of 2600 m. The gas exchange and chlorophyll fluorescence parameters of S. rehderiana significantly increased with increasing altitude, while Q. aquifolioides showed the opposite trend. Leaf anatomical traits, gas exchange, and chlorophyll fluorescence parameters of both species displayed considerable plasticity. There were significant correlations among most leaf traits and between leaf traits and altitude. The survival strategy of Q. aquifolioides was more conservative in response to altitude changes, while that of S. rehderiana was more active. Both species adapted to different altitudes by adjusting their own traits.

Mechanistic insights into diversified photoluminescence behaviours of BF2 complexes of N-benzoyl 2-aminobenzothiazoles.

Many BF2 complexes of heteroaromatics are well known for their dual-state emission (DSE) properties. However, AIE and ACQ effects have also been observed in certain cases. To date, no rational explanations have been proposed for these uncommon photoluminescence (PL) behaviours. The current research prepared four BF2 complexes of N-benzoyl 2-aminobenzothiazoles with diversified photoluminescence (PL) properties as model compounds and utilized quantum chemical calculation tools to address this issue. Theoretical calculations revealed that the electron-donating groups (EDGs) at the para-position of the exocyclic phenyl ring exert significant influence on their ground-state electronic structures and vertical excitation features. Potential energy curve (PEC) analysis showed that the exocyclic phenyl ring and NMe2 could not function as effective rotors due to elevated energy barriers. Only the NPh2 of BFBB-3 could spontaneously rotate ∼60° to induce the formation of an emissive twisted intramolecular charge transfer (TICT) state. The two-channel model involving both vibronic relaxation and S0/S1 surface crossing revealed that the drastic narrowing of the S1/S0 energy gap in the region approaching minimun energy conical intersection (MECI) led to the generation of a dark state in BFBB-1. The small energy barrier to access the dark-state region makes the resulting fast internal conversion a competitive channel for excited-state deactivation. In contrast, the presence of EDGs in BFBB-2 and 4 inhibits this pathway, thereby resulting in intense fluorescence emissions in solution. In addition, crystallographic analysis illustrated that the F atoms perpendicular to the polyheterocycle promoted a slipped face-to-face packing mode and enhanced intermolecular interactions. The efficiencies of their solid-state emissions are mainly affected by the degree of π-π overlaps.

Photoluminescent Properties and Mechanism of Novel Cyanine-Borondifluoride Curcuminoid Hybrids as Red-to-Near Infrared and Endoplasmic Reticulum-Targeting Dyes.

Synthesis-oriented design led us to the discovery of a series of novel cyanine-borondifluoride curcuminoid hybrids called Nanchang Red (NCR) dyes that overcome the intrinsic low synthetic yields of symmetrical cyanine-difluoroboronate (BF2 )-hybridized NIR dyes. The hybridization endows NCR dyes with high molar extinction coefficients, efficient red-to-NIR emission, and enlarged Stokes shifts. Quantum chemical calculations revealed that the asymmetrical layout of the three key electron-withdrawing and electron-donating fragments results in a special pattern of partial charge separation and inconsistent degrees of charge delocalization on their π-conjugated backbones. While the nature of the hemicyanine fragment exerts significant influence on the excitation modes of NCR dyes, the borondifluoride hemicurcuminoid fragment is the major contributor to the enlarged Stokes shifts. Cell imaging experiments illustrated that a subtle change in the N-heterocycle of the hemicyanine fragment has a remarkable effect on the subcellular localization of NCR dyes. Unlike other previously reported cyanine-BF2 hybridized dyes, which mainly target mitochondria, the benzothiazole and indole-based NCR dyes accumulate in both the endoplasmic reticulum (ER) and lipid droplets of HeLa cells, whereas the benzoxazole and quinoline-based NCR dyes stain the ER specifically.

Aerial Oxygen-Driven Selenocyclization of O-Vinylanilides Mediated by Coupled Fe3+/Fe2+ and I2/I- Redox Cycles.

In the past decade, selenocyclization has been extensively exploited for the preparation of a wide range of selenylated heterocycles with versatile activities. Previously, selenium electrophile-based and FeCl3-promoted methods were employed for the synthesis of selenylated benzoxazines. However, these methods are limited by starting material availability and low atomic economy, respectively. Inspired by the recent catalytic selenocyclization approaches based on distinctive pathways, we rationally constructed an efficient and greener double-redox catalytic system for the access to diverse selenylated benzoxazines. The coupling of I2/I- and Fe3+/Fe2+ catalytic redox cycles enables aerial O2 to act as the driving force to promote the selenocyclization. Control and test redox experiments confirmed the roles of each component in the catalytic system, and a PhSeI-based pathway is proposed for the selenocyclization process.

Photo-Switchable Aggregation-Induced Emission of Bisthienylethene-Dipyrimido[2,1-b][1,3]benzothiazole Triad.

A bisthienylethene-dipyrimido[2,1-b][1,3]benzothiazole (BTE-2PBT) triad has been designed and synthesized based on our recent discovery of PBTs as atypical propeller-shaped novel AIEgens. The triad not only maintains the photochromic properties of BTE moiety in solution, film, and solid state but also exhibits remarkable AIE properties. Moreover, the fluorescence of BTE-2PBT PMMA film could be modulated with high contrast by alternate UV and visible light irradiation. Photoerasing, rewriting, and non-destructive readout of fluorescent images on BTE-2PBT PMMA film well demonstrate its potential application as optical memory media.

Fatigue in patients with inflammatory bowel disease in Eastern China.

BACKGROUND: Fatigue is a very common but relatively neglected problem in patients with inflammatory bowel disease (IBD). The prevalence rate of IBD in China is the highest in Asia, but there is little research on fatigue in patients with IBD. Neither the relationship between fatigue and quality of life (QoL) nor the relationship between fatigue and work productivity (WP) in Chinese IBD patients has been reported. AIM: To investigate the prevalence of fatigue related to IBD in Eastern China, to identify the risk factors associated with fatigue, to assess the impact of fatigue on QoL, and to evaluate the relationship between fatigue and WP. METHODS: A cross-sectional study was conducted in a Regional Tertiary IBD Diagnostic and Treatment Center in Eastern China. Clinical data of patients were collected, and disease activity was evaluated. Blood samples were analyzed to assess anemia, albumin, and inflammation. Fatigue was assessed using the multidimensional fatigue inventory. QoL and WP were measured using the short inflammatory bowel disease questionnaire and the work productivity and activity impairment general health questionnaire, respectively. The patients also completed assessments of depression (Patient Health Questionnaire-9) and anxiety (Generalized Anxiety Disorder 7-item Scale). RESULTS: A total of 311 IBD patients, comprising 168 Crohn's disease patients and 143 ulcerative colitis patients, were enrolled. The prevalence of fatigue in patients with IBD was 60.77%. In a univariate logistic regression analysis, factors such as disease activity, depression, anxiety, anemia, and IBD-related surgery were individually related to a significantly increased risk of fatigue in IBD patients. Multivariate logistic regression analysis indicated that depression [odds ratio (OR) = 8.078, 95% confidence interval (CI): 4.113-15.865], anxiety (OR = 2.373, 95%CI: 1.100-5.119), anemia (OR = 2.498, 95%CI: 1.290-4.834), and IBD-related surgery (OR = 2.035, 95%CI: 1.084-3.819) were related to fatigue in IBD patients. There was a negative correlation between fatigue and QoL (r = -0.831; P < 0.0001) but a positive correlation between fatigue and WP loss. CONCLUSION: The prevalence of fatigue in IBD patients in Eastern China is remarkably high even in clinical remission. Factors such as depression, anxiety, anemia, and IBD-related surgery are major risk factors for fatigue in IBD patients. In addition, fatigue has a negative impact on QoL and is positively correlated with WP loss.

A daily activity feature extraction approach based on time series of sensor events.

Activity recognition benefits the lives of residents in a smart home on a daily basis. One of the aims of this technology is to achieve good performance in activity recognition. The extraction and selection of the daily activity feature have a significant effect on this performance. However, commonly used extraction of daily activity features have limited the performance of daily activity recognition. Based on the nature of the time series of sensor events caused by daily activities, this paper presents a novel extraction approach for daily activity feature. First, time tuples are extracted from sensor events to form a time series. Subsequently, several common statistic formulas are proposed to form the space of daily activity features. Finally, a feature selection algorithm is employed to generate final daily activity features. To evaluate the proposed approach, two distinct datasets are adopted for activity recognition based on four different classifiers. The results of the experiment reveal that the proposed approach is an improvement over the commonly used approach.

Hf(OTf)4 as a Highly Potent Catalyst for the Synthesis of Mannich Bases under Solvent-Free Conditions.

Hf(OTf)4 was identified as a highly potent catalyst (0.1-0.5 mol%) for three-component Mannich reaction under solvent-free conditions. Hf(OTf)4-catalyzed Mannich reaction exhibited excellent regioselectivity and diastereoselectivity when alkyl ketones were employed as substrates. 1H NMR tracing of the H/D exchange reaction of ketones in MeOH-d4 indicated that Hf(OTf)4 could significantly promote the keto-enol tautomerization, thereby contributing to the acceleration of reaction rate.

Nested case-control study on risk factors for opportunistic infections in patients with inflammatory bowel disease.

BACKGROUND: When opportunistic infections occur, patients with inflammatory bowel disease (IBD) commonly display a significantly increased rate of morbidity and mortality. With increasing use of immunosuppressive agents and biological agents, opportunistic infections are becoming a hot topic in the perspective of drug safety in IBD patients. Despite the well-established role of opportunistic infections in the prognosis of IBD patients, there are few epidemiological data investigating the incidence of opportunis-tic infections in IBD patients in China. Besides, the risk factors for opportunistic infection in Chinese IBD patients remain unclear. AIM: To predict the incidence of opportunistic infections related to IBD in China, and explore the risk factors for opportunistic infections. METHODS: A single-center, prospective study of IBD patients was conducted. The patients were followed for up to 12 mo to calculate the incidence of infections. For each infected IBD patient, two non-infected IBD patients were selected as controls. A conditional logistic regression analysis was used to assess associations between putative risk factors and opportunistic infections, which are represented as odds ratios (OR) and 95% confidence intervals (CIs). RESULTS: Seventy (28.11%) out of 249 IBD patients developed opportunistic infections. Clostridium difficile infections and respiratory syncytial virus infections were found in 24 and 16 patients, respectively. In a univariate analysis, factors such as the severity of IBD, use of an immunosuppressant or immunosuppressants, high levels of fecal calprotectin, and C-reactive protein or erythrocyte sedimentation rate were individually related to a significantly increased risk of opportunistic infection. Multivariate analysis indicated that the use of any immunosuppressant yielded an OR of 3.247 (95%CI: 1.128-9.341), whereas the use of any two immunosuppressants yielded an OR of 6.457 (95%CI: 1.726-24.152) for opportunistic infection. Interestingly, when immunosuppressants were used in combination with infliximab (IFX) or 5-aminosalicylic acid, a significantly increased risk of opportunistic infection was also observed. The relative risk of opportunistic infection was greatest in IBD patients with severe disease activity (OR = 9.090; 95%CI: 1.532-53.941, relative to the remission stage). However, the use of IFX alone did not increase the risk of opportunistic infection. CONCLUSION: Factors such as severe IBD, elevated levels of fecal calprotectin, and the use of immunosuppressive medications, especially when used in combination, are major risk factors for opportunistic infections in IBD patients. The use of IFX alone does not increase the risk of opportunistic infection.

Efficient Synthesis of UDP-Furanoses via 4,5-Dicyanoimidazole(DCI)-Promoted Coupling of Furanosyl-1-Phosphates with Uridine Phosphoropiperidate.

A P(V)-N activation method based on nucleoside phosphoropiperidate/DCI system has been developed for improved synthesis of diverse UDP-furanoses. The reaction conditions including temperature, amount of activator, and reaction time were optimized to alleviate the degradation of UDP-furanoses to cyclic phosphates. In addition, an efficient and facile phosphoramidite route was employed for the preparation of furanosyl-1-phosphates.

Highly Efficient Synthesis of Substituted 3,4-Dihydropyrimidin-2-(1H)-ones (DHPMs) Catalyzed by Hf(OTf)4: Mechanistic Insights into Reaction Pathways under Metal Lewis Acid Catalysis and Solvent-Free Conditions.

In our studies on the catalytic activity of Group IVB transition metal Lewis acids, Hf(OTf)4 was identified as a highly potent catalyst for "one-pot, three-component" Biginelli reaction. More importantly, it was found that solvent-free conditions, in contrast to solvent-based conditions, could dramatically promote the Hf(OTf)4-catalyzed formation of 3,4-dihydro-pyrimidin-2-(1H)-ones. To provide a mechanistic explanation, we closely examined the catalytic effects of Hf(OTf)4 on all three potential reaction pathways in both "sequential bimolecular condensations" and "one-pot, three-component" manners. The experimental results showed that the synergistic effects of solvent-free conditions and Hf(OTf)4 catalysis not only drastically accelerate Biginelli reaction by enhancing the imine route and activating the enamine route but also avoid the formation of Knoevenagel adduct, which may lead to an undesired byproduct. In addition, ¹H-MMR tracing of the H-D exchange reaction of methyl acetoacetate in MeOH-d4 indicated that Hf(IV) cation may significantly accelerate ketone-enol tautomerization and activate the ß-ketone moiety, thereby contributing to the overall reaction rate.

Mucosa repair mechanisms of Tong-Xie-Yao-Fang mediated by CRH-R2 in murine, dextran sulfate sodium-induced colitis.

AIM: To explore the significance of corticotropin-releasing hormone (CRH)-receptor (R)2 in mucosal healing of dextran sulfate sodium (DSS)-induced colitis and the effect of Tong-Xie-Yao-Fang (TXYF) on CRH-R2 expression and regulation. METHODS: Ulcerative colitis was induced in mice by administration of 3% (w/v) DSS for 7 d. Once the model was established, mice were administered urocortin-2 (30 µg/kg), a peptide which binds exclusively to CRH-R2, or various doses of aqueous TXYF extracts (2.8-11.2 g/kg), a CRH-R2 antagonist Astressin (Ast)2B (20 µg/kg), Ast2B + Ucn2, or Ast2B with various doses of aqueous TXYF extracts for 9 d. Colonic mucosal permeability was then evaluated by measuring the fluorescence intensity in serum. The colitis disease activity index (DAI), histology, body weight loss and colon length were assessed to evaluate the condition of colitis. Terminal deoxynucleotidyl transferase dUTP nick-end labeling was used to detect apoptosis of the intestinal epithelial cells. The expression level of Ki-67 represented the proliferation of colonic epithelial cells and was detected by immunohistochemistry. The expression levels of inflammation cytokines IL-6, TNF-α and CXCL-1 were examined in colon tissues using real-time PCR and ELISA kits. RESULTS: Compared with the DSS group, mice treated with the CRH-R2 antagonist Ast2B showed greater loss of body weight, shorter colon lengths (4.90 ± 0.32 vs 6.21 ± 0.34 cm, P < 0.05), and higher DAI (3.61 ± 0.53 vs 2.42 ± 0.32, P < 0.05) and histological scores (11.50 ± 1.05 vs 8.33 ± 1.03, P < 0.05). Additionally, the Ast2B group showed increased intestinal permeability (2.76 ± 0.11 µg/mL vs 1.47 ± 0.11 µg/mL, P < 0.001), improved secretion of inflammatory cytokines in colon tissue, and reduced colonic epithelial cell proliferation (4.97 ± 4.25 vs 22.51 ± 8.22, P < 0.05). Increased apoptosis (1422.39 ± 90.71 vs 983.01 ± 98.17, P < 0.001) was also demonstrated. The Ucn2 group demonstrated lower DAI (0.87 ± 0.55 vs 2.42 ± 0.32, P < 0.001) and histological scores (4.33 ± 1.50 vs 8.33 ± 1.03, P < 0.05). Diminished weight loss, longer colon length (9.58 ± 0.62 vs 6.21 ± 0.34 cm, P < 0.001), reduced intestinal permeability (0.75 ± 0.07 vs 1.47 ± 0.11 µg/mL, P < 0.001), inhibited secretion of inflammatory cytokines in colon tissue and increased colonic epithelial cell proliferation (90.04 ± 15.50 vs 22.51 ± 8.22, P < 0.01) were all observed. Reduced apoptosis (149.55 ± 21.68 vs 983.01 ± 98.17, P < 0.05) was also observed. However, significant statistical differences in the results of the Ast2B group and Ast2B + Ucn2 group were observed. TXYF was also found to ameliorate symptoms of DSS-induced colitis in mice and to promote mucosal repair like Ucn2. There were significant differences between the Ast2B + TXYF groups and the TXYF groups. CONCLUSION: CRH-R2 activates the intestinal mucosal antiinflammatory response by regulating migration, proliferation and apoptosis of intestinal epithelial cells in colitis-induced mice, and plays an important antiinflammatory role. TXYF promotes mucosal repair in colitis mice by regulating CRH-R2.

An efficient and practical synthesis of formylglycinamide ribonucleotide (FGAR).

An efficient five-step synthetic route for multigram-scale preparation of formylglycinamide ribonucleotide (FGAR) from peracetylated ß-d-ribofuranosyl azide has been developed.

Hafnium(IV) triflate as a potent catalyst for selective 1-O-deacetylation of peracetylated saccharides.

An efficient method for selective anomeric deacetylation of peracetylated mono-, di-, and trisaccharides has been developed by using 2 mol% Hf(OTf)4 as catalyst in acetonitrile. Employment of ultrasonic irradiation could significantly accelerate the reaction rate. Mechanistic study confirmed the hydrolysis nature of this reaction, and NMR experimental data suggested that multiple peracetylated saccharide molecules may ligate to Hf(IV) cation primarily via the anomeric acetate to promote its specific hydrolysis.

Efficient Synthesis of 5-Carboxy-2'-Deoxypyrimidine Nucleoside 5'-Triphosphates.

An efficient P(V)-N activation method for the synthesis of 5-carboxy-2'-deoxyuridine and 5-carboxy-2'-deoxycytidine triphosphates directly from the corresponding phosphoropiperidate precursors has been developed.

Efficient synthesis of cytidine diphosphate choline (CDP-choline) and its analogs.

An efficient P(V)-N activation approach for the synthesis of cytidine diphosphate choline (CDP-choline) and related ribo- and deoxyribonucleotide analogs has been established.