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1.
PLoS One ; 19(4): e0298153, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38603661

RESUMEN

OBJECTIVE: The Da Vinci Robot is the most advanced micro-control system in endoscopic surgical instruments and has gained a lot of valuable experience today. However, the technical feasibility and oncological safety of the robot over open surgery are still uncertain. This work is to systematically evaluate the efficacy of the unilateral axillary approach for robotic surgery compared to open surgery for differentiated thyroid carcinoma. METHODS: PubMed, Embase, Cochrane Library, and Web of Science databases were utilized to search for relevant literatures of robotic thyroid surgery using unilateral axillary approach compared to open thyroid surgery, and a meta-analysis was performed using RevMan software version 5.3. Statistical analysis was performed through Mantle-Haenszel and inverse variance methods. RESULTS: Twelve studies with a total of 2660 patients were included in the meta-analysis. The results showed that compared with the open group, the robotic group had a longer total thyroidectomy time, shorter hospital stay, less intraoperative bleeding, more postoperative drainage, fewer retrieved central lymph nodes, and higher cosmetic satisfaction (all P < 0.05). In contrast, temporary and permanent laryngeal recurrent nerve injury, temporary and permanent hypoparathyroidism or hypocalcemia, brachial plexus nerve injury, number of retrieved central lymph nodes, number of retrieved lymph nodes in the lateral cervical region, number of lymph node metastases in the lateral cervical region, hematoma, seroma, lymphatic leak, stimulated thyroglobulin (sTg) and unstimulated thyroglobulin (uTg), and the number and recurrence rate of patients with sTg <1ng/ml were not statistically different between the two groups (P > 0.05). CONCLUSIONS: The unilateral axillary approach for robotic thyroid surgery may achieve outcomes similar to those of open surgery. Further validation is required in a prospective randomized controlled trial.


Asunto(s)
Adenocarcinoma , Procedimientos Quirúrgicos Robotizados , Robótica , Neoplasias de la Tiroides , Humanos , Procedimientos Quirúrgicos Robotizados/efectos adversos , Tiroglobulina , Estudios Prospectivos , Neoplasias de la Tiroides/cirugía , Neoplasias de la Tiroides/patología , Robótica/métodos , Tiroidectomía/efectos adversos , Adenocarcinoma/cirugía , Estudios Retrospectivos , Disección del Cuello
2.
Animals (Basel) ; 14(8)2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38672381

RESUMEN

Mulberry leaves, a common traditional Chinese medicine, represent a potential nutritional strategy to improve the fat profile, also known as the lipo-nutrition, of pork. However, the effects of mulberry leaves on pork lipo-nutrition and the microorganisms and metabolites in the porcine gut remain unclear. In this study, multi-omics analysis was employed in a Yuxi black pig animal model to explore the possible regulatory mechanism of mulberry leaves on pork quality. Sixty Yuxi black pigs were divided into two groups: the control group (n = 15) was fed a standard diet, and the experimental group (n = 45) was fed a diet supplemented with 8% mulberry leaves. Experiments were performed in three replicates (n = 15 per replicate); the two diets were ensured to be nutritionally balanced, and the feeding period was 120 days. The results showed that pigs receiving the diet supplemented with mulberry leaves had significantly reduced backfat thickness (p < 0.05) and increased intramuscular fat (IMF) content (p < 0.05) compared with pigs receiving the standard diet. Lipidomics analysis showed that mulberry leaves improved the lipid profile composition and increased the proportion of triglycerides (TGs). Interestingly, the IMF content was positively correlated with acyl C18:2 and negatively correlated with C18:1 of differential TGs. In addition, the cecal microbiological analysis showed that mulberry leaves could increase the abundance of bacteria such as UCG-005, Muribaculaceae_norank, Prevotellaceae_NK3B31_group, and Limosilactobacillus. Simultaneously, the relative levels of L-tyrosine-ethyl ester, oleic acid methyl ester, 21-deoxycortisol, N-acetyldihydrosphingosine, and mulberrin were increased. Furthermore, we found that mulberry leaf supplementation significantly increased the mRNA expression of lipoprotein lipase, fatty acid-binding protein 4, and peroxisome proliferators-activated receptor γ in muscle (p < 0.01). Mulberry leaf supplementation significantly increased the mRNA expression of diacylglycerol acyltransferase 1 (p < 0.05) while significantly decreasing the expression of acetyl CoA carboxylase in backfat (p < 0.05). Furthermore, mulberry leaf supplementation significantly upregulated the mRNA expression of hormone-sensitive triglyceride lipase and peroxisome proliferator-activated receptor α (p < 0.05) in backfat. In addition, mulberry leaf supplementation led to increased serum leptin and adiponectin (p < 0.01). Collectively, this omic profile is consistent with an increased ratio of IMF to backfat in the pig model.

3.
J Anim Physiol Anim Nutr (Berl) ; 108(3): 764-777, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38305489

RESUMEN

Mulberry leaf is a widely used protein feed and is often used as a strategy to reduce feed costs and improve meat quality in the livestock industry. However, to date, there is a lack of research on the improvement of meat quality using mulberry leaves, and the exact mechanisms are not yet known. The results showed that fermented mulberry leaves significantly reduced backfat content but had no significant effect on intramuscular fat (IMF). Lipidomic analysis showed that 98 and 303 differential lipid molecules (p < 0.05) were identified in adipose and muscle tissues, respectively, including triglycerides (TG), phosphatidylcholine, phosphatidylethanolamine, sphingolipids, and especially TG; therefore, we analysed the acyl carbon atom number of TG. The statistical results of acyl with different carbon atom numbers of TG in adipose tissue showed that the acyl group containing 13 carbon atoms (C13) in TG was significantly upregulated, whereas C15, C16, C17, and C23 were significantly downregulated, whereas in muscle tissue, the C12, C19, C23, C25, and C26 in TG were significantly downregulated. Acyl changes in TG were different for different numbers of carbon atoms in different tissues. We found that the correlations of C (14-18) in adipose tissue were higher, but in muscle tissue, the correlations of C (18-26) were higher. Through pathway enrichment analysis, we identified six and four metabolic pathways with the highest contributions of differential lipid metabolites in adipose and muscle tissues respectively. These findings suggest that fermented mulberry leaves improve meat quality mainly by inhibiting TG deposition by downregulating medium- and short-chain fatty acids in backfat tissue and long-chain fatty acids in muscle tissue.


Asunto(s)
Tejido Adiposo , Alimentación Animal , Dieta , Fermentación , Morus , Músculo Esquelético , Animales , Morus/química , Porcinos , Tejido Adiposo/metabolismo , Tejido Adiposo/química , Músculo Esquelético/química , Músculo Esquelético/metabolismo , Alimentación Animal/análisis , Dieta/veterinaria , Metabolismo de los Lípidos , Lípidos/química , Lipidómica , Fenómenos Fisiológicos Nutricionales de los Animales , Hojas de la Planta/química
4.
RSC Adv ; 13(10): 6346-6355, 2023 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-36824231

RESUMEN

Effective removal of strontium isotopes in radioactive waste streams has important implications for the environment and the sustainable development of nuclear energy. In this work, a zirconium phosphate/18-crown-ether-6 (ZrP/18C6) composite was prepared using the intercalation method by loading crown ether into zirconium phosphate. The composite was structurally and morphologically characterized by XRD, FT-IR, XPS, and SEM. The adsorption experiments of Sr2+ onto the ZrP/18C6 composite were conducted as a function of temperature, pH, Sr2+ concentration and competing ions. The results indicate ZrP/18C6 can adsorb 98.6% of Sr2+ within 30 minutes at an Sr2+ concentration of 100 mg L-1 and maintain a high removal rate with a distribution coefficient of 7 × 105 mL g-1 when Sr2+ is at a low level of 4.28 mg L-1. The ZrP/18C6 composite reached a maximum adsorption capacity of 195.74 mg g-1 at an Sr2+ concentration of 380 mg L-1, which is significantly higher than the 43.03 mg g-1 of α-ZrP. The adsorption performance of Sr2+ onto ZrP/18C6 is not significantly affected by temperature, pH and competing ions. Furthermore, the adsorption kinetics and thermodynamics were analyzed based on the adsorption data obtained in the present work. It is shown that the adsorption of Sr2+ onto ZrP/18C6 follows the pseudo-second-order model and the Langmuir monolayer model, respectively. Additionally, the adsorption mechanism of Sr2+ by ZrP/18C6 is discussed.

5.
iScience ; 25(11): 105433, 2022 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-36388991

RESUMEN

Nurse logs are common in modern forests from boreal to temperate and tropical ecosystems. However, the evolution of the nurse-log strategy remains elusive because of their rare occurrence in the fossil record. We report seven coniferous nurse logs from lowermost to uppermost Permian strata of northern China that have been colonized by conifer and sphenophyllalean roots. These roots are associated with two types of arthropod coprolites and fungal remains. Our study provides the first glimpse into plant-plant facilitative relationships between late Paleozoic gymnosperms and sphenopsids. Detritivorous arthropods and fungi appear to have been crucial for the utilization of nurse logs in Permian forests. The phylogenetically distant roots demonstrate that nurse-log interaction was a sophisticated seedling strategy in late Paleozoic humid tropical forests, and this approach may have been adopted and developed by a succession of plant groups leading to its wide representation in modern forest ecosystems.

6.
Zhongguo Dang Dai Er Ke Za Zhi ; 20(3): 224-229, 2018 Mar.
Artículo en Chino | MEDLINE | ID: mdl-29530124

RESUMEN

OBJECTIVE: To study the effect of Bifidobacterium on the expression of ß-defensin-2 (BD-2) in intestinal tissue of neonatal rats with necrotizing enterocolitis (NEC). METHODS: A total of 40 rats were randomly divided into four groups: normal control, Bifidobacterium control, NEC model, and Bifidobacterium treatment, with 10 rats in each group. A rat model of NEC was induced by hypoxia, cold stimulation, and artificial feeding. The rats in the Bifidobacterium control and Bifidobacterium treatment groups were given Bifidobacterium via the gastric tube after cold stimulation once a day for three consecutive days. The morphological changes of the terminal ileum were observed under a light microscope and the intestinal injury score was determined. Immunohistochemistry and qRT-PCR were used to measure the protein and mRNA expression of BD-2 in the ileal mucosal tissue. RESULTS: The NEC model group had a significantly higher intestinal injury score than the normal control, Bifidobacterium control, and Bifidobacterium treatment groups (P<0.05). The Bifidobacterium treatment group had a significantly higher intestinal injury score than the normal control and Bifidobacterium control groups (P<0.05). The mRNA and protein expression of BD-2 in the normal control group was significantly lower than in the Bifidobacterium control, NEC model, and Bifidobacterium treatment groups (P<0.05). The Bifidobacterium control group had significantly higher mRNA and protein expression of BD-2 than the NEC model and Bifidobacterium treatment groups (P<0.05). The Bifidobacterium treatment group had significantly higher mRNA and protein expression of BD-2 than the NEC model group (P<0.05). CONCLUSIONS: Bifidobacterium can induce the expression of BD-2 in intestinal tissue of rats and reduce inflammatory response by increasing the expression of BD-2. This provides a protective effect on neonatal rats with NEC.


Asunto(s)
Bifidobacterium , Enterocolitis Necrotizante/terapia , Mucosa Intestinal/metabolismo , beta-Defensinas/fisiología , Animales , Modelos Animales de Enfermedad , Humanos , Recién Nacido , FN-kappa B/fisiología , Ratas , Ratas Sprague-Dawley , Transducción de Señal/fisiología , beta-Defensinas/análisis , beta-Defensinas/genética
7.
Sci Bull (Beijing) ; 63(22): 1462-1463, 2018 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-36658826
8.
Biol Lett ; 13(11)2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-29093177

RESUMEN

Today, cycads are a small group of gymnospermous plants with a limited distribution in the (sub)tropics, but they were major constituents of Mesozoic floras. Fossil leaves sporadically found in latest Carboniferous and Permian floras have putatively been ascribed to cycads. However, their true affinity remains unclear due to the lack of anatomical evidence. Virtually all modern cycads have pinnate leaves, but this type of leaf morphology is by no means unique for cycads. Pinnate leaves of Plagiozamites oblongifolius Halle 1927 with well-preserved cuticles showing the epidermal anatomy are here described from the upper Permian Xuanwei Formation of Yunnan Province, Southwest China. The cuticles show a clear differentiation into costal and intercostal zones; stomata are confined to the intercostal zones on both the upper and lower leaf surfaces. The external morphology and the epidermal anatomy of these fossil leaves are closely comparable with those of extant cycads, particularly members of the family Zamiaceae.


Asunto(s)
Cycadopsida/anatomía & histología , Fósiles , Hojas de la Planta/anatomía & histología , China
9.
Sci Rep ; 5: 12405, 2015 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-26198410

RESUMEN

Leaf traces are important structures in higher plants that connect leaves and the stem vascular system. The anatomy and emission pattern of leaf traces are well studied in extant vascular plants, but remain poorly understood in fossil lineages. We quantitatively analysed the leaf traces in the late Permian conifer Ningxiaites specialis from Northwest China based on serial sections through pith, primary and secondary xylems. A complete leaf traces emission pattern of a conifer is presented for the first time from the late Palaeozoic. Three to five monarch leaf traces are grouped in clusters, arranged in a helical phyllotaxis. The leaf traces in each cluster can be divided into upper, middle and lower portions, and initiate at the pith periphery and cross the wood horizontally. The upper leaf trace increases its diameter during the first growth increment and then diminishes completely, which indicates leaf abscission at the end of the first year. The middle trace immediately bifurcates once or twice to form two or three vascular bundles. The lower trace persists as a single bundle during its entire length. The intricate leaf trace dynamics indicates this fossil plant had a novel evolutionary habit by promoting photosynthetic capability for the matured plant.

10.
Ann Bot ; 111(6): 1075-81, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23532049

RESUMEN

BACKGROUND AND AIMS: Our knowledge of tylosis formation is mainly based on observations of extant plants; however, its developmental and functional significance are less well understood in fossil plants. This study, for the first time, describes a complete tylosis formation in a fossil woody conifer and discusses its ecophysiological implications. METHODS: The permineralized stem of Shenoxylon mirabile was collected from the upper Permian (Changhsingian) Sunjiagou Formation of Shitanjing coalfield, northern China. Samples from different portions of the stem were prepared by using the standard thin-sectioning technique and studied in transmitted light. KEY RESULTS: The outgrowth of ray parenchyma cells protruded into adjacent tracheids through pits initially forming small pyriform or balloon-shaped structures, which became globular or slightly elongated when they reached their maximum size. The tracheid luminae were gradually occluded by densely spaced tyloses. The host tracheids are arranged in distinct concentric zones representing different growth phases of tylosis formation within a single growth ring. CONCLUSIONS: The extensive development of tyloses from the innermost heartwood (metaxylem) tracheids to the outermost sapwood tracheids suggests that the plant was highly vulnerable and reacted strongly to environmental stress. Based on the evidence available, the tyloses were probably not produced in response to wound reaction or pathogenic infection, since evidence of wood traumatic events or fungal invasion are not recognizable. Rather, they may represent an ecophysiological response to the constant environmental stimuli.


Asunto(s)
Fósiles , Tracheophyta/crecimiento & desarrollo , Madera/crecimiento & desarrollo , China
11.
Chin Med J (Engl) ; 125(16): 2902-7, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22932088

RESUMEN

BACKGROUND: Platinum-based regimens are used as standard first-line chemotherapy in non-small cell lung cancer (NSCLC) patients. To study if pharmacogenetic approach may allow a tailored selection of platinum chemotherapy for advanced NSCLC, we performed a meta-analysis to compare chemosensitivity to platinum with different ERCC1 C118T/ MDR1 C3435T single-nucleotide polymorphism (SNP). METHODS: Relevant studies were identified by searching the PubMed, Embase, Cochrane, OVID, Springer, EBSCO and CNKI databases. Inclusion criteria were patients with advanced NSCLC who received platinum-based chemotherapy, an evaluated polymorphism of ERCC/MDR1 and overall response rate. We excluded duplicate publications, letters and review articles. The RevMan 4.2 and STATA 11 package were used to do comprehensive quantitative assessment. RESULTS: A total of 11 studies were included in this meta-analysis. For studies evaluating ERCC1 C118T, test for heterogeneity was done (χ(2) = 13.41, P = 0.1), and the odds ratio (OR) for the wild-type C/C genotype versus the heterozygous C/T and T/T genotypes was 1.50 (95% CI 1.09 - 2.06, P = 0.01). In four studies evaluating MDR1 polymorphism, test for heterogeneity was also done (χ(2) = 3.22, P = 0.36), and the OR for the wild-type C/C genotype versus the heterozygous C/T and T/T genotypes was 2.30 (95% CI 1.44 - 3.68, P = 0.0005). CONCLUSIONS: The results indicated that platinum-based chemotherapy sensitivity was significantly associated with polymorphism of ERCC1 C118T and MDR1 C3435T SNP. In further perspective studies, the ERCC1/MDR1 SNPs might serve as simple and less invasive biomarkers for personalized chemotherapy with platinum-based anticancer drugs.


Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/genética , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/genética , Proteínas de Unión al ADN/genética , Endonucleasas/genética , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Platino (Metal)/uso terapéutico , Polimorfismo Genético/genética , Humanos
12.
Zhongguo Dang Dai Er Ke Za Zhi ; 14(1): 24-7, 2012 Jan.
Artículo en Chino | MEDLINE | ID: mdl-22289747

RESUMEN

OBJECTIVE: To study the relationship between pulmonary surfactant-associated protein B (SP-B) gene polymorphisms and their susceptibility to neonatal respiratory distress syndrome (RDS). METHODS: Eighty-eight preterm infants with RDS (RDS group) and 103 infants without RDS (control group) were enrolled. The genomic DNA was isolated using DNA kits. Polymerase chain reaction with restriction fragment length polymorphism technique was used to detect the genotype and allele frequency of the SP-B -18A/C and SP-B 1580C/T single nucleotide polymorphisms. The association between the polymorphisms and RDS was analyzed. RESULTS: SP-B -18A/C and SP-B 1580C/T were found to be polymorphic in both RDS and control groups. The frequencies of CC genotype (X2=12.26, P<0.01) and C allele (X2=11.97, P<0.01) of SP-B 1580C/T were significantly higher in the RDS group than in the control group. The C allele significantly increased the risk of RDS (OR=2.26, 95%CI: 1.42-3.60). The frequencies of genotype and allele of SP-B -18A/C showed no significant difference between the two groups. CONCLUSIONS: SP-B 1580C/T polymorphism contributes to the etiology of RDS and may serve as the susceptibility gene for RDS. The C allele increases the risk of RDS. SP-B -18A/C shows no association with the etiology of RDS.


Asunto(s)
Predisposición Genética a la Enfermedad , Polimorfismo de Nucleótido Simple , Proteína B Asociada a Surfactante Pulmonar/genética , Síndrome de Dificultad Respiratoria del Recién Nacido/genética , Genotipo , Humanos , Recién Nacido , Síndrome de Dificultad Respiratoria del Recién Nacido/etiología
13.
Arch Med Res ; 42(5): 412-20, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-21827803

RESUMEN

BACKGROUND AND AIMS: With great progress made in individualized chemotherapy, pharmacogenetics is gradually put on the agenda. We performed this meta-analysis to compare outcome to platinum-based chemotherapies in advanced non-small cell lung cancer (NSCLC) with different ERCC1 C118T/C8092A and MDR1 C3435T polymorphisms. METHODS: Relevant studies were identified according to search strategy in this meta-analysis. Inclusion criteria were patients with advanced NSCLC who were receiving platinum-based chemotherapies. We evaluated the relationship between single nucleotide polymorphisms (SNP) and outcome of platinum-based chemotherapies. RevMan and STATA package were used for the comprehensive quantitative analyses. RESULTS: Twenty studies were included in the meta-analysis. There was no significant association between SNPs and objective response or overall survival of platinum-based chemotherapies with CC vs. CT/TT: ERCC1 C118T (OR 1.21, 95% CI 0.81-1.82 for objective response; HR 1.09, 95% CI 0.79-1.51 for overall survival); ERCC1 C8092A SNP (OR 0.84, 95% CI 0.59-1.18; HR 1.26, 95% CI 0.68-2.36) and MDR1 C3435T SNP (HR 1.11, 95% CI 0.78-1.56). Ethnic stratification provided the same results. We found a significant difference for MDR1 C3435T (OR 2.22, 95% CI 1.46-3.37; OR 2.63, 95% CI 1.56-4.45 for Asians; OR 1.61, 95% CI 0.79-3.28 for Caucasians). CONCLUSIONS: We found no evidence to support the use of ERCC1 C118T/C8092A polymorphisms as prognostic predictors of platinum-based chemotherapies in NSCLC. For the MDR1 C3435T SNP, a significant association with objective response was detected for CC genotype in overall and Asian populations stratified. Multiple and large-scale studies with ethnic stratification are required for the correlation between biomarkers and tumor prognosis.


Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/genética , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Proteínas de Unión al ADN/genética , Endonucleasas/genética , Neoplasias Pulmonares/tratamiento farmacológico , Polimorfismo de Nucleótido Simple , Subfamilia B de Transportador de Casetes de Unión a ATP , Carcinoma de Pulmón de Células no Pequeñas/genética , Humanos , Neoplasias Pulmonares/genética , Resultado del Tratamiento
14.
Oncol Lett ; 2(4): 643-647, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22848242

RESUMEN

The present study aimed to examine the combined effects of oxaliplatin (L-OHP) and rapamycin (RAPA) in the HCT116 colon cancer cell line. The growth inhibitory effect was evaluated by MTT assay as a monotherapy or combination therapy. IC(50) values were determined using CalcuSyn 2.0 software. To determine the interaction of the drugs, the combination index (CI) was calculated using the Chou-Talalay method. Apoptosis was investigated using flow cytometry and Western blotting. Acridine orange staining was employed to observe morphological changes. The results showed the IC(50) values of L-OHP and RAPA to be 8.35±0.78 µM (r=0.99) and 223.44±38.10 nM (r=0.94), respectively. CI was ≤1 when L-OHP was used at doses ranging from 1 to 5 µM plus RAPA at a dose of 10 nM, suggesting synergistic or additive effects. CI was ≥1 when 100 nM RAPA was used in combination with low-dose L-OHP, showing additive to antagonistic effects. The combination of L-OHP (1 µM) and RAPA (10 nM) induced 19.76% Annexin V-positive cells, which was found to be higher than L-OHP (11.45%, p<0.01) or RAPA (6.89%, p<0.01) alone. The cleaved PARP protein expression levels were highest after 48 h of combination treatment. Acridine orange staining showed typical bright red Acidic vesicular organelles in the RAPA group, whereas the green condensed chromatin in the apoptotic bodies was found in both the L-OHP and combination groups. In conclusion, at a cytostatic concentration, RAPA was found to potentiate the anti-tumor effects of low-dose L-OHP in the HCT116 colon cancer cell by inducing enhanced apoptosis.

15.
Inorg Chem ; 49(18): 8270-5, 2010 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-20718431

RESUMEN

In an attempt to synthesize novel zirconium phosphate materials, a series of syntheses have been performed in a deep eutectic solvent (DES), composed of tetrapropylammonium bromide (TPABr) and oxalic acid. As a result, this DES does not act as a template provider in reaction probably owing to the steric effects of the longer chains of the TPA cation, and only the α-Zr(HPO(4))(2)·H(2)O (α-ZrP) phase has been achieved. However, after organic amine was added to the initial reaction mixture in a normal way, the additives did act as a template to induce the zirconium phosphate framework. For example, with 1,4-dimethylpiperazine as an additive, a novel layered compound, [C(6)H(16)N(2)](0.5)Zr(H(0.5)PO(4))(2)·H(2)O (denoted as ZrPO(4)-DES8) was obtained. Its structure was determined from single-crystal X-ray diffraction (XRD) data and consists of zirconium phosphate layers with the protonated 1,4-dimethylpiperazine and water molecules in between. Interestingly, the two layered materials as additives in a liquid lubricant exhibit excellent friction behavior with higher load-carrying and antiwear capacities in comparison to typical lubricant additives such as MoS(2) and graphite, increase the P(B) value of the base oil by 27.2% and 8.5%, and decrease the wear scar diameter of the base oil by 43% and 36%, respectively. Scanning electron microscopy, XRD, and energy-dispersive X-ray spectrometry are used to investigate the lubricant behavior of those materials.

16.
Angew Chem Int Ed Engl ; 48(12): 2206-9, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19199313

RESUMEN

On their best behavior: Three zirconium compounds with one-, two-, and three-dimensional structures have been successfully synthesized by the ionothermal approach. The 3D zirconium phosphate (see picture; F green, H white, O red, P pink, Zr yellow) exhibits high catalytic performance, with a cyclohexane conversion ratio of 32% and cyclohexanone selectivity of up to 83%.

17.
J Chromatogr A ; 1019(1-2): 101-9, 2003 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-14650608

RESUMEN

This article reports an analytical method for separating, identifying and quantitating sulfur-containing compounds and their groups in diesel oils (170-400 degrees C) using comprehensive two-dimensional gas chromatography coupled with a sulfur chemiluminescence detector. The identification of target compounds and their groups was based on standard substances, the group separation feature and tile-effect of comprehensive two-dimensional gas chromatography. The quantitative analysis on major sulfur compounds and total sulfur was carried out based on the linear response of sulfur chemiluminescence detector and the internal standards method. The results of total sulfur determination in the samples were compared with those from ASTM D 4294 standard method, the R.S.D. percentage were <6.02%, correctness of this method can meet the industrial requirement. To the end, the method developed was used to investigate the sulfur-containing compounds in different diesel oils, the result shows that the distribution of sulfur-containing compounds in diesel oils from different process units are apparently different. The sulfur compounds in fluid catalytic cracking (FCC), residuum fluid catalytic cracking (RFCC) diesel oils mainly exist in the form of alkyl-substituted dibenzothiophenes that add up to about 40-50% of the total sulfur, while this number is only 6-8 and 20-28% in visbreaking (VB) and delayed-coking (DC) diesel oils, respectively.


Asunto(s)
Cromatografía de Gases/métodos , Gasolina/análisis , Azufre/análisis , Mediciones Luminiscentes
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