The controllable and efficient synthesis of two-dimensional metal-organic framework nanosheets for heterogeneous catalysis.

Two-dimensional (2D) MOFs exhibit unique periodicity in surface structures and thus have attracted much interest in the fields of catalysis, energy, and sensors. However, the expanded production scale of 2D MOFs had remained a great challenge in most previous studies. Herein, a controllable and efficient crystallization method for synthesizing 2D MOF nanosheets using high-gravity reactive precipitation is proposed, significantly improving heterogeneous catalysis efficiency. The two-dimensional ZIF-L nanosheets prepared in a rotating packed bed (RPB) reactor show a smaller lateral and lamellar thickness and a higher BET surface area compared to ZIF-L nanosheets prepared in a conventional stirred tank reactor (STR), with a greatly shortened reaction time. Applying the ZIF-L-RPB nanosheets as a catalyst, the catalytic Knoevenagel condensation as a probe reaction displays a high conversion rate of benzaldehyde (99.3%) within 2 h at room temperature, greatly exceeding that displayed by ZIF-L-STR and other reported catalysts. Furthermore, ZIL-L-RPB nanosheets of only 0.2 wt% enhanced the catalytic activity for the glycolysis of poly(ethylene terephthalate) (PET) with a PET conversion and a monomer yield of 90% in a short period of 15 min at 195 °C and almost completely depolymerized PET with a monomer yield of 94% in 30 min, which was far above that achieved by ZIL-L-STR. These results indicate the promising prospects of a high-gravity reactive precipitation strategy with precise size control in an economical way to prepare high-activity 2D MOF nanosheets for a wide range of heterogeneous catalysis.

A Universal Approach for Controllable Synthesis of Homogeneously Alloyed PtM Nanoflowers toward Enhanced Methanol Oxidation.

Platinum (Pt)-based alloys have received considerable attention due to their compositional variability and unique electrochemical properties. However, homogeneous element distribution at the nanoscale, which is beneficial to various electrocatalytic reactions, is still a great challenge. Herein, a universal approach is proposed to synthesize homogeneously alloyed and size-tunable Pt-based nanoflowers utilizing high gravity technology. Owing to the significant intensification of micro-mixing and mass transfer in unique high gravity shearing surroundings, five typical binary/ternary Pt-based nanoflowers are instantaneously achieved at room temperature. As a proof-of-concept, as-synthesized Platinum-Silver nanoflowers (PtAg NFs) demonstrate excellent catalytic performance and anti-CO poisoning ability for anodic methanol oxidation reaction with high mass activity of 1830 mA mgPt -1, 3.5 and 3.2 times higher than those of conventional beaker products and commercial Pt/C, respectively. The experiment in combination with theory calculations suggest that the enhanced performance is due to additional electronic transmission and optimized d-band center of Pt caused by high alloying degree.

[Research advances in shrub dendroecology]. / çŒæœ¨å¹´è½®ç”Ÿæ€å­¦ç ”ç©¶è¿›å±•.

The ecological value of shrub-ring data has received more and more attention. The tree-ring data of shrub species have been increasingly used to reveal growth dynamics of regional shrub vegetation and its sensitivity to climate change. Up to now, nearly 70 species of shrubs have been used in the studies of shrub dendrochronology, which considerably broadened the traditional tree-ring research network, enriched the research scope and object of dendrochronology, and certainly with great significance in revealing the characteristics of regional climate fluctuation and annual dynamics of structure, function and service for shrubland ecosystems. In this study, we systematically collected dendrochronological studies based on shrub species during the 1996-2021, and reviewed research progress in four main subfields (physiology, climatology, ecology and hydrology) in dendrochronology for shrub species. The characteristics of shrub growth and xylem anatomy under different environmental stresses were expounded. The main limiting factors for shrub growth in different climatic conditions and the history of regional climate fluctuations based on shrub-ring data were revealed. The individual growth and population dynamics of shrub species driven by climate and the changes in ecosystems caused by non-climatic factors were assessed, and the reconstructions of regional hydrological histories were compiled using tree-ring data of shrub species. Under the context of global warming, dendrochronological studies of shrub species in China should pay more attention to the responses of shrub species radial growth to drought stress under different moisture conditions in the semi-arid and arid regions and the transforming feature of distribution pattern and climate response sensitivity for shrub species under the background of climate change.

Influence of nutritional intervention on children with type 1 diabetes mellitus and DPP-4 in serum.

The level of dipeptidyl peptidase-4 (DPP-4) of children with type 1 diabetes mellitus (T1DM) was observed to evaluate the improvement in function of the nutritional intervention. In total, 132 children with T1DM (T1DM group) and 132 healthy children (NC group) based on physical examination admitted to our hospital from September 2014 to June 2015 and were studied. General data of the two groups as well as the concentration of DPP-4 and various biochemical criterion in peripheral serum were collected and analyzed. Compared with NC group, DPP-4 level of T1DM group was obviously increased (P<0.05); after insulin treatment, the serum level of DPP-4 of T1DM group decreased, but was still significantly higher than that of NC group (P<0.05). After 3 months of clinical nutritional intervention, body mass index (BMI) of children with T1DM was significantly reduced compared with data before the treatment (P<0.05). However, the level of DPP-4 appeared unchanged (P>0.05). Pearson's correlation analysis showed that the level of DPP-4 had a positive correlation with diabetic duration, BMI and gamma (γ)-glutamyl transpeptidase for children suffering TIDM (P<0.05). Multiple linear regression analysis showed that BMI may be a factor influencing DPP-4 level in serum of T1DM children. In conclusion, the level of DPP-4 in serum increased, and insulin treatment was able to decrease DPP-4 level in T1DM children. However, clinical nutritional intervention could not improve the level of DPP-4 and BMI may be an influental factor of the DPP-4 level.

Primary Melanotic Paraganglioma of Thyroid Gland: Report of a Rare Case With Clinicopathologic and Immunohistochemical Analysis and a Literature Review.

BACKGROUND: Pigmented paraganglioma is a special type of paraganglioma, and it is rare in the thyroid. CASE PRESENTATION: We report a case of a 41-year-old woman who had complained of a mass in the thyroid gland. Histology revealed tumor cells arranged in a nest-like or organoid pattern, separated by delicate fibrovascular septa. Two distinct components were observed. In the first, which constituted the majority of the tumor cells, no pigments were observed. In the second, a few cells with pigment showed intercellular substance, but the structure was unclear. Using immunohistochemistry, cells in the first component were confirmed to be diffuse strong positive for synaptophysin, but negative for chromogranin A, pan-cytokeratin, calcitonin, and thyroglobulin. About 1% of tumor cells were stained by Ki-67. In the margins of the tumor, a few cells were observed to be positive for HMB-45 and Melan A after bleaching by oxalic acid. The stromal cells were positive for S-100. Using electron microscopy, a few cells containing many round melanin bodies with greater electron density granules of nonuniform size were observed. The diagnosis of primary melanotic paraganglioma of the thyroid gland was made. CONCLUSION: Primary melanotic paraganglioma of the thyroid gland is a rare, low malignant potential tumor. To the best of our knowledge, this is the first case described.

The rice TCD11 encoding plastid ribosomal protein S6 is essential for chloroplast development at low temperature.

Plastid ribosome proteins (PRPs) are important components for chloroplast biogenesis and early chloroplast development. Although it has been known that chloroplast ribosomes are similar to bacterial ones, the precise molecular function of ribosomal proteins remains to be elucidated in rice. Here, we identified a novel rice mutant, designated tcd11 (thermo-sensitive chlorophyll-deficient mutant 11), characterized by the albino phenotype until it died at 20°C, while displaying normal phenotype at 32°C. The alteration of leaf color in tcd11 mutants was aligned with chlorophyll (Chl) content and chloroplast development. The map-based cloning and molecular complementation showed that TCD11 encodes the ribosomal small subunit protein S6 in chloroplasts (RPS6). TCD11 was abundantly expressed in leaves, suggesting its different expressions in tissues. In addition, the disruption of TCD11 greatly reduced the transcript levels of certain chloroplasts-associated genes and prevented the assembly of ribosome in chloroplasts at low temperature (20°C), whereas they recovered to nearly normal levels at high temperature (32°C). Thus, our data indicate that TCD11 plays an important role in chloroplast development at low temperature. Upon our knowledge, the observations from this study provide a first glimpse into the importance of RPS6 function in rice chloroplast development.

Downregulation of leptin inhibits growth and induces apoptosis of lung cancer cells via the Notch and JAK/STAT3 signaling pathways.

Previous studies have documented that leptin is involved in the pathogenesis of many human cancer types by regulation of numerous signal transduction pathways. The aim of this study was to investigate the biological roles of leptin and the mechanisms attributed to its action in non-small cell lung cancer (NSCLC) cell lines. The expression of leptin was measured by quantitative real-time PCR and western blot in seven NSCLC cell lines. Proliferation and apoptosis of NSCLC cells in response to leptin knockdown were determined by MTT assay and flow cytometry, respectively. The effect of leptin knockdown on the Notch and JAK/STAT3 signaling pathways was further examined by western blot. Leptin expression was significantly increased in NSCLC cell lines compared with normal human bronchial epithelial cell HBE. Leptin knockdown inhibited cell proliferation and induced apoptosis in NSCLC cell lines through inactivation of the Notch and JAK/STAT3 signaling pathways. Furthermore, gene silencing of Notch signaling with Notch-1 siRNA or inhibition of JAK/STAT3 signaling by JSI-124, an inhibitor of STAT3, resulted in proliferation inhibition and apoptosis induction in NSCLC A549 cells. Our findings suggested that leptin knockdown could become a new approach for the prevention of lung cancer progression, which is likely to be mediated at least partially by inactivation of the Notch and JAK/STAT3 signaling pathways.

Importance of the rice TCD9 encoding α subunit of chaperonin protein 60 (Cpn60α) for the chloroplast development during the early leaf stage.

The chloroplast development governs plant growth and metabolism. This study characterized a novel rice thermo-sensitive chloroplast development 9 (tcd9) mutant, which exhibited the albino phenotype before the 3-leaf stage grown below 24 °C whereas displayed normal green at over 28 °C or even at 20 °C after 5-leaf stage. The obvious decrease in Chl levels, abnormal chloroplasts with few thylakoid lamella and abnormal thylakoids were observed for the albino mutant seedlings at low temperature, but the mutant was apparently normal green at high temperature, suggesting the thermo-sensitivity of albino phenotype. Genetic analysis showed that the albino phenotype was controlled by a single recessive nuclear gene (tcd9). The map-based cloning and molecular complementation tests revealed that the mutation of TCD9 encoding α subunit of Cpn60 protein (Cpn60α), localized in chloroplasts, was responsible for albino phenotype. In addition, TCD9 exhibited the high expression in all tested tissues, especially in young leaves. The transcriptional analysis indicated that all expression levels of the studied genes related to chloroplast development in tcd9 mutant were seriously affected in the albino seedlings at 20 °C, whereas some of them recovered into normal levels in green-seedlings at 32 °C. Our observations suggest that the nuclear-encoded Cpn60α protein TCD9 plays a crucial role in chloroplast development at early leaf stage of rice.

Immunolocalization of ß-catenin and Lef-1 during postnatal hair follicle development in mice.

It is well recognized that the Wnt pathway, in which ß-catenin and Lef-1 are important factors, is associated with many physiological processes, including embryogenesis and postnatal development. The Wnt pathway also plays a critical role in the development of skin. It regulates the formation of the dorsal dermis and epidermal appendages in the skin and the activity of epithelial stem cells. In this study, we investigated the presence and localization of ß-catenin and Lef-1 in murine hair follicles through the first postnatal month, which encompasses the first hair cycle in mice, using Western blotting and immunohistochemistry. Our results show that ß-catenin and Lef-1 are expressed during all stages in a hair cycle, most strongly in the anagen and weakly in the catagen and telogen phases. The results also suggest that the ß-catenin-Lef-1 complex may regulate hair follicle cycling. This process will be of considerable interest to future studies.

[Characteristics and molecular mapping of a novel chlorophyll-deficient yellow-leaf mutant in rice].

A yellow-leaf mutant (yl11) with chlorophyll-deficient in rice (Oryza sativa L.) was selected from the progeny of a japonica rice variety "Jiahua 1" treated with 60Co γ-radiation. In comparison with the wild-type parent, "Jiahua 1", the mutant had yellow-leaves at whole growth stages and displayed significantly decreased in chlorophyll content and net photosynthetic rate. Underdeveloped chloroplast and alterations of the major agronomic traits, such as plant-heights, were also observed in the mutant. Genetic analysis confirmed that the yellow-leaf mutant trait was controlled by a single recessive nuclear gene (yl11). Using SSR and In/Del molecular markers and 920 F2 and F3 plants from the cross of yl11 with the indica variety Peiai 64S, the yl11 was mapped between the molecular markers MM2199 and InDel21039 with a physical distance of 110 kb on the long arm of chromosome 11, in which no known functional genes for chlorophyll synthesis or chloroplast development in rice has been found. These findings will provide a foundation for the cloning and functional analysis of this gene in the future.

[Lipid peroxidation and biomechanical properties of artery in hyperlipemia rats after treating with tetrahydrobiopterin].

OBJECTIVE: To explore the effect of the level of lipid peroxidation and biomechanical properties after chronic treating with tetrahydrobiopterin (BH4) in thoracic aorta of hyperlipemia (HL) rats. METHODS: HL rats were given BH4 chronically. The opening angle in the zero-stress state and the relationship between pressure and diameter (P-D) of mesenteric artery were measured by computer image 8, 16, and 24 week-old respectively. RESULTS: Treating with BH4 chronically from 8 week-old in HL rats, there was a significant increase in the zero-stress state of opening angle of thoracic aorta. The P-D curve of mesenteric artery moved upward. CONCLUSION: Treating with BH4 prevented the structure and function of artery from abnormal changing, and attenuated lipid peroxidation in HL rats.

[Mapping of QTLs controlling leaf chlorphyll content and chlorphyll degradation speed of detached leaves in rice].

A recombinant inbred (RI) population derived from the cross between an indica variety, IR24, and a japonica variety, Asominori, was used to map QTLs controlling leaf chlorophyll content (LCC) and chlorophyll degradation speed (CDS) of detached leaves collected at the tillering stage of rice through composite interval mapping analysis (CIM). Resultantly, four QTLs (qLCC-3, qLCC-5, qLCC-7, qLCC-12) controlling LCC and three QTLs (qCDS-1, qCDS-6, qCDS-7) associated with CDS were detected respectively. Among them, qCDS-7 with the largest effect for CDS, located on chromosome 7, coincided with the genomic region of qLCC-7 for LCC detected. Those results from this study basically can explicate the genetic basis associated with leaf chlorophyll content and chlorophyll degradation speed of detached leaves in rice, which might be available for a rapid determination of leaf senescence at early growth-stages and breeding of high-photosynthetic efficiency in rice.

Dihydroarteannuin ameliorates lupus symptom of BXSB mice by inhibiting production of TNF-alpha and blocking the signaling pathway NF-kappa B translocation.

The aim of this study was to investigate the mechanisms of action of Dihydroarteannuin (DHA), a semi-synthesized agent from the starting material artemisinin extracted from the Chinese Traditional Herbs Artemisia annua, on ameliorating the symptoms of lupus on BXSB mice. The concentration of TNF-alpha in the culture supernatant of the peritoneal macrophages and in the sera of BXSB mice was determined by the ELISA method. NF-kappaB protein expression and translocation were assayed by the EMSA method and laser confocal scanning microscopy method, respectively. IkappaB-alpha and NF-kappaB p65 protein expression were determined by the Western blot method. Renal tissue of the BXSB mice was prepared for assaying inhibitory activity of DHA on NF-kappaB, p65 and IkappaB-alpha protein expression in vivo. The peritoneal macrophages were prepared for analysis inhibitory effects of DHA on translocation of NF-kappaB into nuclear in vitro. We found that DHA strongly reduced the production of TNF-alpha in the culture supernatant of the peritoneal macrophages and in the sera of BXSB mice in vitro or in vivo. The results demonstrated that DHA decreased the expression of NF-kappaB subunit p65 protein and the activation of NF-kappaB in the renal tissue of BXSB mice in vivo. DHA effectively inhibited the nuclear translocation of NF-kappaB in peritoneal macrophages of BXSB mice in vitro. Furthermore, it was demonstrated that the degradation of IkappaB-alpha protein was significantly inhibited by DHA. These observations suggested that the inhibitory effects of DHA on TNF-alpha production may result from the block in the NF-kappaB signaling pathway upstream of IkappaB degradation.

[Effect of dihydro-qinghaosu on auto-antibody production, TNF alpha secretion and pathologic change of lupus nephritis in BXSB mice].

OBJECTIVE: To investigate the effect of dihydro-qinghaosu (DQHS) on auto-antibody production, TNF alpha secretion and pathologic change of lupus nephritis in BXSB mice and the possible mechanism of DQHS in treating systemic lupus erythematosus (SLE). METHODS: Anti ds-DNA antibody and TNF alpha in serum of the BXSB mice were detected by enzyme linked immunosorbent assay (ELISA). Renal tissue was stained by HE and Masson. RESULTS: In the height and moderate dose DQHS groups, as compared with the model group, levels of anti-ds-DNA antibody and serum TNF alpha were significantly lower (P < 0.05); and renal pathological change was milder. CONCLUSION: DQHS could inhibit the production of anti-ds-DNA antibody and secretion of TNF alpha and improve the pathologic lesion of lupus nephritis in BXSB mice.