Your browser doesn't support javascript.
loading
Montrer: 20 | 50 | 100
Résultats 1 - 14 de 14
Filtrer
1.
Article de Anglais | MEDLINE | ID: mdl-38639617

RÉSUMÉ

Objective: This study aims to identify contributing factors to adverse reactions related to central venous catheter (CVC) usage in patients with HIV/AIDS, to enhance patient care and treatment outcomes. Methods: To obtain the most relevant and recent findings, we conducted a systematic search across reputable databases, including PubMed, EMBASE, and the Cochrane Library, focusing on randomized controlled trials from 2010 to 2023. Two researchers independently led the literature search and screening process, using a thorough pre-structured form for data extraction and performing a risk of bias assessment on selected studies. Statistical synthesis of the data was conducted using the advanced Review Manager 5.3 software. We compared the prevalence of opportunistic infections, the rate of venous inflammation, and the incidence of venous thrombosis in patients with HIV/AIDS undergoing central venous catheter placement. Results: The comprehensive exploration led to the inclusion of seven randomized controlled trials, involving 251 instances of central venous catheter placements in patients with HIV/AIDS. The meta-analysis findings revealed a lower prevalence of opportunistic infections in patients with CVCs placed, as indicated by the relative risk [95% Confidence Interval (CI) (2.53), P < .01]. Similarly, the rate of venous inflammation was significantly reduced [95% CI (2.53), P < .01]. However, the rates of venous thrombosis showed no statistically significant variance [95% CI (2.01), P > .1]. Conclusions: The use of central venous catheters in treating HIV/AIDS patients appears to reduce the occurrence of opportunistic infections and venous inflammation, suggesting potential therapeutic benefits. However, the presence of biases within the included studies and notable heterogeneity among them impede the reliability of these conclusions. Therefore, it is imperative to pursue validation through additional high-quality clinical trials.

2.
Cell Death Dis ; 14(12): 802, 2023 12 07.
Article de Anglais | MEDLINE | ID: mdl-38062041

RÉSUMÉ

POU5F1 plays an important role in maintaining the cancer stem cell (CSC) -like properties of gastric cancer (GC) cells. The impact of POU5F1 on the proliferation and metastasis of GC was examined, along with the potential of ATRA as a specific therapeutic agent for GC. The dysregulation of POU5F1 expression in GC tissues was analyzed using public databases and bioinformatics techniques, and the disparity in POU5F1 expression between normal gastric tissues and GC tissues was further assessed through western blot, RT-qPCR, and immunohistochemistry. The present study aimed to investigate the impact of POU5F1 on the proliferation, migration, and invasion of GC cells through both in vivo and in vitro experiments. Additionally, the effects of ATRA on the proliferation, migration, and invasion of GC cells were examined using in vivo and in vitro approaches. Our findings revealed a significant upregulation of POU5F1 in GC tissues, which was found to be associated with a poorer prognosis in patients with GC. Moreover, POU5F1 was observed to enhance the proliferation, migration, and invasion of GC cells in vitro, as well as promote subcutaneous tumor growth and lung metastasis of GC cells in vivo. The overexpression of POU5F1 mechanistically triggers the process of Epithelial-mesenchymal transition (EMT) by down-regulating E-Cadherin and up-regulating N-Cadherin and VIM. POU5F1 hinders the ubiquitination of TRAF6 through negative regulation of TRIM59, thereby facilitating the activation of the NF-κB pathway. Furthermore, the administration of ATRA effectively impedes the proliferation, migration, and invasion of GC cells by suppressing the expression of POU5F1. The upregulation of POU5F1 elicits EMT, fosters the initiation of the NF-κB signaling pathway in GC cells, and stimulates the proliferation, invasion, and metastasis of GC cells. All-trans retinoic acid (ATRA) can impede these POU5F1-induced effects, thereby potentially serving as an adjunctive therapeutic approach for GC.


Sujet(s)
Tumeurs de l'estomac , Humains , Tumeurs de l'estomac/anatomopathologie , Facteur-6 associé aux récepteurs de TNF/génétique , Facteur-6 associé aux récepteurs de TNF/métabolisme , Facteur de transcription NF-kappa B/métabolisme , Invasion tumorale/génétique , Prolifération cellulaire , Mouvement cellulaire , Transition épithélio-mésenchymateuse , Ubiquitination , Lignée cellulaire tumorale , Régulation de l'expression des gènes tumoraux , Facteur de transcription Oct-3/génétique , Facteur de transcription Oct-3/métabolisme , Protéines à motif tripartite/métabolisme , Protéines et peptides de signalisation intracellulaire/métabolisme
3.
World J Gastroenterol ; 29(21): 3280-3291, 2023 Jun 07.
Article de Anglais | MEDLINE | ID: mdl-37377582

RÉSUMÉ

BACKGROUND: Fibroblast growth factor (FGF) 15/19, which is expressed in and secreted from the distal ileum, can regulate hepatic glucose metabolism in an endocrine manner. The levels of both bile acids (BAs) and FGF15/19 are elevated after bariatric surgery. However, it is unclear whether the increase in FGF15/19 is induced by BAs. Moreover, it remains to be understood whether FGF15/19 elevations contribute to improvements in hepatic glucose metabolism after bariatric surgery. AIM: To investigate the mechanism of improvement of hepatic glucose metabolism by elevated BAs after sleeve gastrectomy (SG). METHODS: By calculating and comparing the changes of body weight after SG with SHAM group, we examined the weight-loss effect of SG. The oral glucose tolerance test (OGTT) test and area under the curve of OGTT curves were used to assess the anti-diabetic effects of SG. By detecting the glycogen content, expression and activity of glycogen synthase as well as the glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (Pepck), we evaluated the hepatic glycogen content and gluconeogenesis activity. We examined the levels of total BA (TBA) together with the farnesoid X receptor (FXR)-agonistic BA subspecies in systemic serum and portal vein at week 12 post-surgery. Then the histological expression of ileal FXR and FGF15 and hepatic FGF receptor 4 (FGFR4) with its corresponding signal pathways involved in glucose metabolism were detected. RESULTS: After surgery, food intake and body weight gain of SG group was decreased compare with the SHAM group. The hepatic glycogen content and glycogen synthase activity was significantly stimulated after SG, while the expression of the key enzyme for hepatic gluconeogenesis: G6Pase and Pepck, were depressed. TBA levels in serum and portal vein were both elevated after SG, the FXR-agonistic BA subspecies: Chenodeoxycholic acid (CDCA), lithocholic acid (LCA) in serum and CDCA, DCA, LCA in portal vein were all higher in SG group than that in SHAM group. Consequently, the ileal expression of FXR and FGF15 were also advanced in SG group. Moreover, the hepatic expression of FGFR4 was stimulated in SG-operated rats. As a result, the activity of its corresponding pathway for glycogen synthesis: FGFR4-Ras-extracellular signal regulated kinase pathway was stimulated, while the corresponding pathway for hepatic gluconeogenesis: FGFR4- cAMP regulatory element-binding protein- peroxisome proliferator-activated receptor γ coactivator-1α pathway was suppressed. CONCLUSION: Elevated BAs after SG induced FGF15 expression in distal ileum by activating their receptor FXR. Furthermore, the promoted FGF15 partly mediated the improving effects on hepatic glucose metabolism of SG.


Sujet(s)
Facteurs de croissance fibroblastique , Glucose , Rats , Animaux , Glucose/métabolisme , Facteurs de croissance fibroblastique/métabolisme , Glycogen synthase/métabolisme , Glycogène hépatique/métabolisme , Foie/métabolisme , Poids , Acides et sels biliaires/métabolisme , Gastrectomie
4.
Inflamm Bowel Dis ; 29(12): 1854-1864, 2023 Dec 05.
Article de Anglais | MEDLINE | ID: mdl-37300504

RÉSUMÉ

BACKGROUND: Patients with ulcerative colitis (UC) may be prone to colitis-associated colorectal cancer (CAC), but there is still a poor understanding of the underlying mechanism so far. This study intended to clarify the role of pro-inflammatory cytokines and miR-615-5p in this process. METHODS: This experiment first detected miR-615-5p expressions in paraffin-embedded sections of colonic tissues from patients with UC and CAC. Then, we investigated the mechanism through which pro-inflammatory cytokines affected miR-615-5p. Furthermore, in vivo and in vitro tests were performed to identify how miR-615-5p affected colorectal cancer (CRC). Dual-luciferase reporter assay was then employed to identify the targeting relationship between miR-615-5p and stanniocalcin-1 (STC1). RESULTS: The miR-615-5p was lowly expressed in both cancerous and noncancerous colonic tissues of patients with CAC. Pro-inflammatory cytokines downregulated miR-615-5p expression. Overexpression of miR-615-5p reduced the proliferation and migration of CRC cells and had a certain therapeutic effect on in human CRC xenograft mice. Stanniocalcin-1 was identified to be a target gene of miR-615-5p and was involved in the effect of miR-615-5p on CRC. CONCLUSIONS: During the progression from UC to CAC, pro-inflammatory cytokines downregulate miR-615-5p, which may induce the upregulation of STC1, and promote the occurrence and development of tumors. These findings offer new insights into the mechanism of CAC and may indicate novel tumor markers or therapeutic targets.


Sujet(s)
Néoplasmes associés aux colites , Tumeurs colorectales , microARN , Animaux , Humains , Souris , Prolifération cellulaire/physiologie , Tumeurs colorectales/génétique , Tumeurs colorectales/métabolisme , Cytokines/métabolisme , microARN/génétique , microARN/métabolisme
5.
Therap Adv Gastroenterol ; 16: 17562848231170470, 2023.
Article de Anglais | MEDLINE | ID: mdl-37163166

RÉSUMÉ

Background: The growing numbers of early esophageal cancer (EEC) have increased the demand for endoscopic therapy. Objectives: To clarify the influential factors for the prognosis of patients with EEC receiving endoscopic surgery, and to construct a nomogram to evaluate the prognostic value of endoscopic therapy. Design: Prognostic analysis study. Methods: Clinical data of EEC patients who received endoscopic therapy between 2004 and 2015 were collected from the Surveillance, Epidemiology, and End Results database and used to construct the nomogram. The prognosis was analyzed by R language; the nomogram was constructed by Cox survival analysis; and the accuracy of the nomogram was verified by C index and the receiver operating characteristic (ROC) and calibration curves. X-Tile software was used to stratify the risk of patients. Results: Our study constructed the nomogram of the prognosis of patients with EEC treated by endoscopic surgery, including 1118 patients and 5 independent prognostic factors of esophageal cancer-specific survival. The C index and the area under the ROC curve (AUC) of the training and verification cohorts were all >0.75. The calibration curve also reflected the good consistency of the model in predicting survival. Significant difference in the risk of patients from different stratifications with the same T staging existed, and the model had a better C index than that of the T staging. Conclusion: Our study reports potential influential factors affecting the prognosis of EEC patients who received endoscopic therapy and establishes a reliable nomogram to predict the risk and prognosis, which has certain advantages compared with traditional TNM staging system.

6.
Front Surg ; 9: 858236, 2022.
Article de Anglais | MEDLINE | ID: mdl-35599787

RÉSUMÉ

Background and Aim: To evaluate the safety and efficacy of laparoscopy distal gastrectomy using a linear stapler compared with a circular stapler in patients with gastric cancer. Methods: We retrospectively reviewed 173 patients who underwent laparoscopic distal gastrectomy for gastric cancer at a single center from January 2018 to December 2020. Patients were categorized into the linear stapler group and the circular stapler group. General data, intraoperative and postoperative outcomes, postoperative pathological results, postoperative complications, and postoperative follow-up in the two groups were compared and analyzed. Results: The operation time (208.76 ± 32.92 vs. 226.69 ± 26.92 min, p < 0.05), anastomosis time (71.87 ± 9.50 vs. 90.56 ± 3.18 min, p < 0.05), time to first flatus (68.60 ± 25.96 vs. 76.16 ± 21.05 h, p < 0.05), time to the first sip of water (3.66 ± 0.61 vs. 4.07 ± 0.77 days, p < 0.05), and time to the first liquid diet (4.43 ± 1.02 vs. 5.03 ± 1.70 days, p < 0.05) were significantly shorter in the linear stapler group. In addition, the highest postoperative body temperature within 3 days (37.4 ± 0.61 vs. 37.7 ± 0.61, p < 0.05) after the operation, white blood cell count (WBC) on the 3rd day (9.07 ± 2.52 vs. 10.01 ± 2.98 × 10∧9/L, p < 0.05), and average gastric tube drainage within 3 days (36.65 ± 24.57 vs. 52.61 ± 37 ml, p < 0.05) were also significantly lower in the linear stapler group. Conclusions: Both circular and linear staplers are safe and feasible for gastrointestinal reconstruction in laparoscopic distal gastrectomy. In contrast, a linear stapler has advantages over a circular stapler in shortening operation time and accelerating the postoperative recovery of patients.

7.
Aging (Albany NY) ; 14(9): 3887-3909, 2022 05 04.
Article de Anglais | MEDLINE | ID: mdl-35507914

RÉSUMÉ

BACKGROUND: This study aimed to investigate the relationship of dyslipidemia and interleukin-enhancer binding factor 3 (ILF3) in gastric cancer, and provide insights into the potential application of statins as an agent to prevent and treat gastric cancer. METHODS: The expression levels of ILF3 in gastric cancer were examined with publicly available datasets such as TCGA, and western blotting and immunohistochemistry were performed to determine the expression of ILF3 in clinical specimens. The effects of ox-LDL on expression of ILF3 were further verified with western blot analyses. RNA sequencing, Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and Gene Set Enrichment Analysis (GSEA) pathway analyses were performed to reveal the potential downstream signaling pathway targets of ILF3. The effects of statins and ILF3 on PI3K/AKT/mTOR signaling pathway, cell proliferation, cell cycle, migration and invasion of gastric cancer cells were investigated with Edu assay, flow cytometry and transwell assay. RESULTS: Immunohistochemistry and western blot demonstrated that the positive expression rates of ILF3 in gastric cancer tissues were higher than adjacent mucosa tissues. The ox-LDL promoted the expression of ILF3 in a time-concentration-dependent manner. ILF3 promoted the proliferation, cell cycle, migration and invasion by activating the PI3K/AKT/mTOR signaling pathway. Statins inhibited the proliferation, cell cycle, migration and invasion of gastric cancer by inhibiting the expression of ILF3. CONCLUSIONS: These findings demonstrate that ox-LDL promotes ILF3 overexpression to regulate gastric cancer progression by activating the PI3K/AKT/mTOR signaling pathway. Statins inhibits the expression of ILF3, which might be a new targeted therapy for gastric cancer.


Sujet(s)
Inhibiteurs de l'hydroxyméthylglutaryl-CoA réductase , Tumeurs de l'estomac , Lignée cellulaire tumorale , Mouvement cellulaire , Prolifération cellulaire , Humains , Inhibiteurs de l'hydroxyméthylglutaryl-CoA réductase/pharmacologie , Lipoprotéines LDL , Facteurs nucléaires-90/génétique , Facteurs nucléaires-90/métabolisme , Phosphatidylinositol 3-kinases/métabolisme , Protéines proto-oncogènes c-akt/métabolisme , Transduction du signal , Tumeurs de l'estomac/génétique , Tumeurs de l'estomac/métabolisme , Sérine-thréonine kinases TOR/métabolisme
8.
Sci Rep ; 12(1): 6026, 2022 04 11.
Article de Anglais | MEDLINE | ID: mdl-35410341

RÉSUMÉ

To investigate the clinical value and significance of preoperative three-dimensional computerized tomography angiography (CTA) in laparoscopic radical gastrectomy for gastric cancer. The clinical data were analyzed retrospectively from 214 gastric cancer patients. We grouped according to whether to perform CTA, and we compared and analyzed the difference of the data between the two groups. The perigastric arteries were classified according to CTA images of patients in the CTA group. The celiac trunk was classified according to Adachi classification: Type I (118/125, 94.4%), Type II (3/125, 2.4%), Type III (0/125, 0%), Type IV (1/125, 0.8%), Type V (2/125, 1.6%), Type VI (1/125, 0.8%). Hepatic artery classification was performed according to Hiatt classification: Type I (102/125, 81.6%), Type II (9/125, 7.2%), Type III (6/125, 4.8%), Type IV (2/125, 1.6%), Type V (3/125, 2.4%), Type VI (0, 0%), Others (3/125, 2.4%). And this study combined vascular anatomy and surgical risk to establish a new splenic artery classification model. In comparison, the operation time, first exhaust time, and estimated blood loss in the CTA group were significantly lower than those in the non-CTA group. In addition, the blood loss in the CTA group combined with ICG (Indocyanine Green) labeled fluorescence laparoscopy was significantly less than that in the group without ICG labeled. Preoperative CTA could objectively evaluate patients' vascular route and variation and then help us avoid or decrease the risk of vascular injury and bleeding. When combined with ICG labeled fluorescence laparoscopy, it could further reduce the risk of iatrogenic injury during the operation and improve postoperative recovery.


Sujet(s)
Laparoscopie , Tumeurs de l'estomac , Angiographie par tomodensitométrie , Gastrectomie/méthodes , Artère hépatique , Humains , Études rétrospectives , Tumeurs de l'estomac/imagerie diagnostique , Tumeurs de l'estomac/chirurgie
9.
Front Oncol ; 12: 847341, 2022.
Article de Anglais | MEDLINE | ID: mdl-35311067

RÉSUMÉ

Background: This study aimed to observe the application and evaluate the feasibility and safety of indocyanine green (ICG) fluorescence technology in laparoscopic radical gastrectomy (LRG). Methods: Patients who underwent LRG & D2 lymphadenectomy at Qilu Hospital of Shandong University were included between January 2018 and August 2019. According to whether endoscopic injection of ICG was performed, patients were assigned to the ICG group (n=107) and the control group (n=88). The clinicopathologic features, retrieved lymph nodes, postoperative recovery, and follow-up data were compared between the two groups. Results: Baseline characteristics are comparable. The ICG group had a significantly larger number of lymph nodes retrieved (49.55 ± 12.72 vs. 44.44 ± 10.20, P<0.05), shorter total operation time (min) (198.22 ± 13.14 vs. 202.50 ± 9.91, P<0.05), shorter dissection time (min) (90.90 ± 5.34 vs. 93.74 ± 5.35, P<0.05) and less blood loss (ml) (27.51 ± 12.83 vs. 32.02 ± 17.99, P<0.05). The median follow-up time was 29.0 months (range 1.5-43.8 months), and there was no significant difference between the ICG group and the control group in 2-year OS (87.8% vs. 82.9%, P>0.05) or DFS (86.0% vs. 80.7%, P>0.05). Conclusions: ICG fluorescence technology in laparoscopic radical gastrectomy has advantages in LN dissection, operation time, and intraoperative blood loss. The 2-year OS and 2-year DFS rates between the two groups were comparable. In conclusion, ICG fluorescence technology is feasible and safe.

10.
Small ; 16(45): e2003426, 2020 Nov.
Article de Anglais | MEDLINE | ID: mdl-33079468

RÉSUMÉ

Homogeneous graphene dispersions with tunable concentrations are fundamental prerequisites for the preparation of graphene-based materials. Here, a strategy for effectively dispersing graphene using graphene oxide (GO) to produce homogeneous, tunable, and ultrahigh concentration graphene dispersions (>150 mg mL-1 ) is proposed. The structure of GO with abundant edge-bound hydrophilic carboxyl groups and in-plane hydrophobic π-conjugated domains allows it to function as a special "surfactant" that enables graphene dispersion. In acidic solutions, GO sheets tend to form edge-to-edge hydrogen bonds and expose the π-conjugated regions which interact with graphene, thereby promoting graphene dispersion. While in alkaline solutions, GO sheets tend to stack in a surface-to-surface manner, thereby blocking the π-conjugated regions and impeding graphene dispersion. As the concentration of GO-dispersed graphene dispersion (GO/G) increases, a continuous transition between four states is obtained, including a dilute dispersion, a thick paste, a free-standing gel, and a kneadable, playdough-like material. Furthermore, GO/G can be applied to create desirable structures including highly conductive graphene films with excellent flexibility, thereby demonstrating an immense potential in flexible composite materials.

11.
Gene ; 754: 144851, 2020 Sep 05.
Article de Anglais | MEDLINE | ID: mdl-32525044

RÉSUMÉ

Tumor angiogenesis is a common feature of rapidly growing solid tumors, accelerated by tumor hypoxia. It is associated with subsequent metastasis, progression, poor prognosis, and aggressive phenotype in many types of cancer. The hypoxia-inducible factors/vascular endothelial growth factor 1(HIF1/VEGF) signal pathway plays an important role in tumor angiogenesis. Proteasome-mediated ubiquitin degradation pathway is one of the most important processes involved in regulating the level of cellular HIF-1α. Our study revealed that Histone Deacetylase 1 (HDAC1) directly inhibits the ubiquitination of HIF1α. Additionally, HDAC1 activates HIF1α/VEGFA signaling pathway, promoting s tumor angiogenesis. These findings have enhanced our understanding of the molecular mechanisms of colorectal (CRC) tumor angiogenesis. HDAC1/HIF1α/VEGFA signaling pathway may provide a novel therapeutic window for CRC.


Sujet(s)
Tumeurs colorectales/anatomopathologie , Régulation de l'expression des gènes tumoraux , Histone Deacetylase 1/métabolisme , Sous-unité alpha du facteur-1 induit par l'hypoxie/métabolisme , Néovascularisation pathologique/anatomopathologie , Facteur de croissance endothéliale vasculaire de type A/métabolisme , Animaux , Apoptose , Marqueurs biologiques tumoraux , Cycle cellulaire , Mouvement cellulaire , Prolifération cellulaire , Tumeurs colorectales/génétique , Tumeurs colorectales/métabolisme , Évolution de la maladie , Histone Deacetylase 1/génétique , Humains , Sous-unité alpha du facteur-1 induit par l'hypoxie/génétique , Mâle , Souris , Souris nude , Invasion tumorale , Néovascularisation pathologique/génétique , Néovascularisation pathologique/métabolisme , Pronostic , Transduction du signal , Cellules cancéreuses en culture , Facteur de croissance endothéliale vasculaire de type A/génétique , Tests d'activité antitumorale sur modèle de xénogreffe
12.
Aging (Albany NY) ; 12(12): 11685-11697, 2020 06 21.
Article de Anglais | MEDLINE | ID: mdl-32564010

RÉSUMÉ

In this study, we investigated the mechanistic role and prognostic significance of the long coding RNA (lncRNA) KCNQ1OT1 in colorectal cancer (CRC). KCNQ1OT1 levels were significantly higher in CRC tissues than adjacent normal colorectal tissues (n=79). High KCNQ1OT1 expression correlated with poorer prognosis in CRC patients. KCNQ1OT1-silenced CRC cells showed reduced proliferation, colony formation, extracellular acidification, and lactate and glucose secretion. This suggests KCNQ1OT1 promotes CRC cell proliferation by increasing aerobic glycolysis. RNA pull-down assays with biotinylated KCNQ1OT1 followed by mass spectrometry analysis showed that KCNQ1OT1 directly binds to hexokinase 2 (HK2). This was confirmed by RNA immunoprecipitation assays using anti-hexokinase 2 antibody. HK2 protein levels were reduced in KCNQ1OT1 knockdown CRC cells, but were restored by treatment with the proteasomal inhibitor MG132. KCNQ1OT1 knockdown CRC cells also showed higher ubiquitinated-HK2 levels, suggesting KCNQ1OT1 enhances aerobic glycolysis by stabilizing HK2. HK2 overexpression in KCNQ1OT1 knockdown CRC cells restored proliferation and aerobic glycolysis. KCNQ1OT1 levels correlated positively with HK2 expression and prognosis in CRC patients. These findings show that KCNQ1OT1 promotes colorectal carcinogenesis by increasing aerobic glycolysis through HK2.


Sujet(s)
Carcinogenèse/génétique , Tumeurs colorectales/génétique , Hexokinase/génétique , Effet Warburg en oncologie , Carcinogenèse/anatomopathologie , Prolifération cellulaire/génétique , Tumeurs colorectales/mortalité , Tumeurs colorectales/anatomopathologie , Tumeurs colorectales/chirurgie , Survie sans rechute , Femelle , Régulation de l'expression des gènes tumoraux , Techniques de knock-down de gènes , Glucose/métabolisme , Cellules HCT116 , Humains , Estimation de Kaplan-Meier , Mâle , Adulte d'âge moyen , Canaux potassiques voltage-dépendants/génétique , Canaux potassiques voltage-dépendants/métabolisme , Pronostic , Stabilité protéique
13.
Angew Chem Int Ed Engl ; 53(31): 8070-3, 2014 Jul 28.
Article de Anglais | MEDLINE | ID: mdl-24853411

RÉSUMÉ

Nucleation and growth methods offer scalable means of synthesizing colloidal particles with precisely specified size for applications in chemical research, industry, and medicine. These methods have been used to prepare a class of silicone gel particles that display a range of programmable properties and narrow size distributions. The acoustic contrast factor of these particles in water is estimated and can be tuned such that the particles undergo acoustophoresis to either the pressure nodes or antinodes of acoustic standing waves. These particles can be synthesized to display surface functional groups that can be covalently modified for a range of bioanalytical and acoustophoretic sorting applications.


Sujet(s)
Acoustique , Siloxanes/synthèse chimique , Gels , Microscopie électronique à balayage , Siloxanes/composition chimique
14.
Nanoscale ; 6(12): 6557-62, 2014 Jun 21.
Article de Anglais | MEDLINE | ID: mdl-24740171

RÉSUMÉ

For the first time, mesoporous Fe3O4@ZnO sphere decorated graphene (GN-pFe3O4@ZnO) composites with uniform size, considerable porosity, high magnetization and extraordinary electromagnetic (EM) wave absorption properties were synthesized by a simple and efficient three-step method. Structure and morphology details were characterized by X-ray diffraction, transmission electron microscopy, high-resolution electron microscopy and field-emission scanning electron microscopy. Electron microscopy images reveal that pFe3O4@ZnO spheres with obvious porous and core-shell structures are uniformly coated on both sides of the GN sheets without significant numbers of vacancies or apparent aggregation. EM wave absorption properties of epoxy containing 30 wt% GN-pFe3O4@ZnO were investigated at room temperature in the frequency region of 0.2-18 GHz. The absorption bandwidth with reflection loss (RL) values less than -10 dB is up to 11.4 GHz, and the minimal RL is almost -40 dB. The intrinsic physical and chemical properties of the materials, the synergy of Fe3O4 and ZnO, and particularly the unique multi-interfaces are fundamental to the enhancement of EM absorption properties. The as-prepared GN-pFe3O4@ZnO composites are shown to be lightweight, have strong absorption, and broad frequency bandwidth EM absorbers.

SÉLECTION CITATIONS
DÉTAIL DE RECHERCHE