The Influence of Fused Deposition Modeling Parameters on the Properties of PA6/PA66 Composite Specimens by the Taguchi Method and Analysis of Variance.

Fused deposition modeling (FDM) is widely used in the rapid prototyping of polymers. Polyamide (PA) has excellent mechanical properties, but its application in FDM is limited due to its high water absorption, warpage, and forming shrinkage. The material of the filament and the printing parameters of the printer are two critical aspects that affect the performance of a component. The prepared PA6/PA66 (composite polyamide [COPA], PA6:PA66 = 85:15) composite (COPA: acrylonitrile butadiene styrene [ABS]: maleic anhydride grafted acrylonitrile butadiene styrene [ABS-g-MAH]: polyethylene = 800:133:67:100) has low water absorption (0.39%) and high dimensional stability, which has a good application prospect in FDM. The influence of eight FDM parameters, including three rarely reported, on the properties of PA6/PA66 composite specimens was investigated by the Taguchi method. The significance of influencing factors was evaluated by analysis of variance (ANOVA) and the stability by signal-noise ratio. When the layer thickness was 0.15 mm, the infill pattern was zigzags, the build plate adhesion type was brim, and the distance from the nozzle to the printing platform and the layer thickness (ΔL) was 0.05 mm; the specimens' dimensional accuracy, surface quality, and mechanical properties were better than other levels. The layer thickness and infill pattern were the two most important factors. The switch of the cooling fan and the temperature printing platform played a significant role in the specimens' dimensional accuracy and surface quality. ΔL tremendously influenced the thickness and warping degree of the specimens. The preparation of high-performance PA composites and the investigation of multiparameters by the Taguchi method provide a possible solution for applying polyamide in FDM.

Enhanced arsenite removal in aqueous with Fe-Ce-Cu ternary oxide nanoparticle.

Arsenite is both more harmful and challenging to get out of water than arsenate. For enhanced As (III) removal, a ternary oxide nanoparticle (FCCTO) mainly composed of iron(Fe), with a small proportion of cerium(Ce) and copper(Cu) was created using a coprecipitation-calcination process. FCCTO was found to be effective in removing As (III) from water, with factors such as adsorbent dose, pH, temperature, and coexisting anions influencing its efficiency. The surface area of FCCTO reached 180.2 m2/g and the doping significantly increased its pore volume and diameter. The adsorption process on FCCTO was endothermic and spontaneous. Ce and Cu in FCCTO were able to efficiently oxidize 81.3% As (III) to As(V). Abundant sites were provided by surface hydroxyl groups for arsenic adsorption. The maximal As(III) adsorption capacity of this adsorbent under the synergistic impact of oxidation and adsorption was 101.5 mg/g. After five cycles, the FCCTO's As(III) adsorption rate dropped to 60% as a result of tetravalent Ce consumption. Surface complexation, redox, and adsorption all had a significant impact on the adsorption process. Overall, FCCTO was an excellent adsorbent with benefits of being facile fabrication, environmentally, recyclable, and having a high As(III) adsorption capacity.

Activated mineral adsorbent for the efficient removal of Pb(II) and Cd(II) from aqueous solution: adsorption performance and mechanism studies.

Activated mineral adsorbent (AMA) was prepared via double salts (Na2SO4 and CaCO3) heat treatment activation of solid-state potassium feldspar. Adsorption performance of AMA for Cd(II) and Pb(II) was investigated by batch mode and factors affecting adsorption including pH value, initial concentration of adsorbate, contact time, adsorbent dosage and temperature on adsorption performance for Cd(II) and Pb(II) were studied. The results indicated that the adsorption process was pH dependent, endothermic and spontaneous. When the adsorption process of Cd(II) and Pb(II) on AMA reached equilibrium, the maximum saturated adsorption capacities were 263.16 and 303.03 mg/g for Cd(II) and Pb(II) ions, respectively, showing higher adsorption removal efficiency. The Langmuir adsorption isotherm and pseudo second kinetic equation could well fit the adsorption process of Cd(II) and Pb(II) by AMA. Besides, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were also performed to further reveal the adsorption mechanism. The results indicated that ion exchange, precipitation and adsorption played an important role in adsorption process. From the investigation, it was concluded that AMA was an excellent adsorbent with the advantages of environment-friendly, inexpensive, facile preparation and higher adsorption capacity of toxic Cd(II) and Pb(II) ions.

Synthesis, Cr(VI) removal performance and mechanism of nanoscale zero-valent iron modified potassium-doped graphitic carbon nitride.

A novel composite (nZVI@K-GCN) was firstly synthesized by liquid phase reducing nanoscale zero-valent iron (nZVI) on potassium-doped graphitic carbon nitride (K-GCN). The results of Fourier transform infrared (FTIR) spectrometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) suggested that nZVI@K-GCN possessed abundant active functional groups such as terminal amino-groups (-NH or -NH2 groups) and -OH, and the specific surface area and pore volume from BET of nZVI@K-GCN were 4.7 times and 3.7 times higher than that of graphitic carbon nitride (GCN), respectively. These properties showed that the composite was especially suitable for heavy metal treatment. The application of the composite in the removal of chromium(VI) from aqueous solution showed that the maximum adsorption capacity of nZVI@K-GCN towards Cr(VI) was 68.6 mg/g at 308 K when the initial concentration of Cr(VI) was 30 mg/L, and more than 99% removal was obtained at pH = 3. This adsorption was an endothermic and spontaneous process. XPS patterns and batch experiments proved that complexation, electrostatic attraction and reduction precipitation were the main adsorption mechanism for Cr(VI) on nZVI@K-GCN.

Effect of a novel Ca-Si composite mineral on Cd bioavailability, transport and accumulation in paddy soil-rice system.

Ubiquitous cadmium (Cd) contamination in mine impacted paddy soil has been jeopardizing regional rice quality, which represents a dominant pathway of Cd exposure in populations depending on a rice diet. Two major aspects of mitigation, soil liming and Si fertilization, were integrated and investigated with a Ca-Si-rich composite mineral (CS) derived from feldspar and carbonate. With the CS amendment, bioavailable Cd in rice rhizosphere was reduced by 92-100% from tillering to maturation stage, paralleled by a marked increase in Cd bound to Fe/Mn oxides and carbonate. As indicated by XRD analysis, the much reduced labile pool of Cd in the CS-amended soil could be mainly attributed to Cd (co)precipitation (Cd(OH)2, Cd2(OH)3Cl, CH6Br3CdN) and surface complexation on more negatively charged oxides at elevated soil pH with CS addition. EDX line scan illustrated much more intensified Si deposition along root cross-section in the CS treatment, which resulted in 1.5-2.1-fold higher Cd sequestration in the CS-amended root than control. As a direct result, the root-to-shoots Cd translocation was reduced significantly by 42-51%, while a slightly less significant decrease in brown rice Cd was obtained with the CS treatment relative to control. The CS amendment showed differing effects on brown rice mineral accumulation, with 1.2-1.5-fold increase in brown rice Zn and simultaneously reduced Fe, Mn, Mg and Cu in brown rice. Our results call the readers' attention to the potential impact of soil ameliorator on grain mineral uptake, and we suggest that proper fortification with mineral fertilizers should be supplemented to assist sustainable rice production with improved mineral nutrition.

Preparation of bio-based magnetic adsorbent and application for efficient removal of Cd(II) from water.

A novel magnetic bio-adsorbent (MCIA) was developed, characterized and tested for its Cd(II) removal from aqueous solution. MCIA could be easily separated from the solution after equilibrium adsorption due to its super-paramagnetic property. The functional and magnetic bio-material was an attractive adsorbent for the removal of Cd(II) from aqueous solution owing to the abundant adsorption sites, amino-group and oxygen-containing groups on the surface of Cyclosorus interruptus. The experimental results indicated that the MCIA exhibited excellent adsorption ability and the adsorption process was spontaneous and endothermic. The adsorption isotherm was consistent with the Langmuir model. The adsorption kinetic fitted the pseudo-second-order model very well. The maximum adsorption capacity of Cd(II) onto MCIA was 40.8, 49.4, 54.6 and 56.6 mg/g at 293, 303, 313 and 323 K, respectively. And the MCIA exhibited an excellent reusability and impressive regeneration. Therefore, MCIA could serve as a sustainable, efficient and low-cost magnetic adsorbent for Cd(II) removal from aqueous solution.

Removal of mercury ions from aqueous solution by thiourea-functionalized magnetic biosorbent: Preparation and mechanism study.

A novel magnetic bio-material (MCIT) was synthesized via coupling reaction and functional modification after load of Fe3O4 nano-particle on the puckered surface of cyclosorus interruptus (CI). The synthesized material was characterized by fourier transform infrared (FTIR), field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS) and X-ray powder diffractometer (XRD). The influence factors like pH, temperatures, contact time, initial concentration and cycle times on the adsorption of Hg (II) in aqueous solution were studied. Adsorption isotherm, kinetics, selectivity and mechanism were investigated. The results indicated that the isotherm model well agreed with monolayer adsorption model. The adsorption process could be divided into three steps, which included a fast step controlled by chemical adsorption, a slow step limited by intraparticle diffusion and an equilibrium stage. The maximum adsorption capacity of Hg (II) was 385.3mg/g at 318K. MCIT possessed high reusability (retained 93% after five successive cycles) and sharply magnetic nature (9.5emu/g), which endowed it easy and efficient separation from aqueous solution.

Biosorption of U(VI) by modified Hottentot Fern: Kinetics and equilibrium studies.

Batch experiments were conducted to investigate the biosorption of U(VI) onto Hottentot Fern (Cyclosorus interruptus). The selective adsorption, the adsorption of different sections of Cyclosorus interruptus (CI), and the adsorption of polluted CI compared with that of unpolluted one were studied in detail. The raw CI and the CI modified by CaCl2, MgCl2, MgCl2/H2O2 were investigated for adsorption of U(VI) from aqueous solution. The results indicate that raw CI showed good adsorption selectivity for U(VI), compared with the adsorption of Cu(II), Co(II) and Ni(II). The stem of CI possesses a prominent adsorption capacity compared to the leaf and root of CI, and the unpolluted CI showed its superiority in adsorption capacity than the polluted CI. Adsorption rate was very fast during the first 30 min in the whole adsorption process. The pseudo-second-order kinetics model was proposed for the adsorption of U(VI) and the equilibrium data fitted well to Langmuir adsorption isotherms. The maximum adsorption capacity of R-CI, Ca-CI, Mg-CI and Mg/H2O2-CI is 41.67, 52.63, 62.50 and 71.43 mg g-1 at 20 °C, respectively.

Gene expression profiling of colorectal tumors and normal mucosa by microarrays meta-analysis using prediction analysis of microarray, artificial neural network, classification, and regression trees.

BACKGROUND: Microarray technology shows great potential but previous studies were limited by small number of samples in the colorectal cancer (CRC) research. The aims of this study are to investigate gene expression profile of CRCs by pooling cDNA microarrays using PAM, ANN, and decision trees (CART and C5.0). METHODS: Pooled 16 datasets contained 88 normal mucosal tissues and 1186 CRCs. PAM was performed to identify significant expressed genes in CRCs and models of PAM, ANN, CART, and C5.0 were constructed for screening candidate genes via ranking gene order of significances. RESULTS: The first screening identified 55 genes. The test accuracy of each model was over 0.97 averagely. Less than eight genes achieve excellent classification accuracy. Combining the results of four models, we found the top eight differential genes in CRCs; suppressor genes, CA7, SPIB, GUCA2B, AQP8, IL6R and CWH43; oncogenes, SPP1 and TCN1. Genes of higher significances showed lower variation in rank ordering by different methods. CONCLUSION: We adopted a two-tier genetic screen, which not only reduced the number of candidate genes but also yielded good accuracy (nearly 100%). This method can be applied to future studies. Among the top eight genes, CA7, TCN1, and CWH43 have not been reported to be related to CRC.

CDH1 polymorphisms and haplotypes in sporadic diffuse and intestinal gastric cancer: a case-control study based on direct sequencing analysis.

BACKGROUND: Findings related to the influence of the -160C → A promoter polymorphism and haplotypes of the E-cadherin (CDH1) gene have not been consistent in previous studies regarding the risk for sporadic gastric cancer. Investigators in most previous studies detected those genotypes using restriction fragment length polymorphism analysis. Therefore, we conducted a case-control study to investigate the association of the CDH1 - 160C → A promoter polymorphism and haplotypes for cancer risk related to sporadic diffuse and intestinal gastric cancer by direct sequencing analysis. METHODS: We included 107 diffuse gastric cancer cases, 60 intestinal gastric cancer cases and 134 controls. The genotypic polymorphisms in the -160 promoter region, exons and intron-exon boundaries of CDH1 were detected by direct sequencing analysis. Genotype frequencies were compared. The CDH1 - 160C → A promoter polymorphism and four polymorphisms (48 + 6 T → C, 2076C → T, 2253C → T and 1937-13 T → C) were included in the haplotype analyses, which were estimated using the expectation-maximization algorithm. RESULTS: Compared to controls, the frequency of the -160A allele was significantly higher in diffuse gastric cancer cases (P = 0.005), but it was not significantly different in intestinal gastric cancer cases (P = 0.119). Two sets of three-marker haplotypes (-160C → A, 48 + 6 T → C, 2076C → T and -160C → A, 1937-13 T → C, 2253C → T) were associated with the risk of diffuse gastric cancer (P = 0.011 and P = 0.042, respectively). CONCLUSION: Based on direct sequencing analysis, our findings suggest that the CDH1 - 160C → A promoter polymorphism and haplotypes play significant roles in cancer risk for sporadic diffuse gastric cancer, but not for intestinal gastric cancer, in a Taiwanese population.

[Ultraviolet-visible spectrometry analysis of insoluble xanthate heavy metal complexes].

A ultraviolet-visible spectrometry method of determining insoluble xanthate heavy metal complexes in flotation wastewater was the first time to be put forward. In this work, the changes of ultraviolet-visible spectra of xanthate solution after the addition of various heavy metal ions were investigated firstly. It was found that Pb2+ and Cu2+ can form insoluble complexes with xanthate, while Fe2+, Zn2+ and Mn2+ have little effect on the ultraviolet absorption of xanthate solution. Then the removal efficiencies of filter membrane with different pore sizes were compared, and the 0.22 µm membrane was found to be effective to separate copper xanthate or lead xanthate from the filtrate. Furthermore, the results of the study on the reaction of sodium sulfide and insoluble xanthate heavy metal complexes showed that S(2-) can release the xanthate ion quantitatively from insoluble complexes to solution. Based on the above research, it was concluded that the amount of insoluble xanthate heavy metal complexes in water samples can be obtained through the increase of free xanthate in the filtrate after the addition of sodium sulfide. Finally, the feasibility of this method was verified by the application to the analysis of flotation wastewater from three ore-dressing plants in the Thirty-six Coves in Chenzhou.

Phosphorus-modified poly(styrene-co-divinylbenzene)-PAMAM chelating resin for the adsorption of uranium(VI) in aqueous.

Polyamidoamine (PAMAM) modified poly(styrene-co-divinylbenzene) absorbents carrying phosphorus functional groups (PS-PAMAM-PPA) were prepared and used as adsorbents for the adsorption of uranium(VI) from aqueous solution. Different generations of PAMAM were used for obtaining different chelating resins, PS-PPA, PS-1.0G PAMAM-PPA, PS-2.0G PAMAM-PPA, PS-3.0G PAMAM-PPA and PS-4.0G PAMAM-PPA. The synthesized resins were characterized by FTIR and XPS. The effects of many physio-chemical properties on metal ion adsorption to adsorbent phase, such as solution pH, kinetic studies, initial uranium concentration, temperature, were investigated using batch method. The results showed that the maximum adsorption capacity (99.89 mg/g) was observed at the pH 5.0 and 25°C with initial U(VI) concentration 100mg/L and adsorbent dose 1g/L. PS-1.0G PAMAM-PPA had the largest adsorption capacity for U(VI) compared with other prepared adsorbents. The adsorption kinetics of U(VI) onto PS-1.0G PAMAM-PPA followed the mechanism of the pseudo-second-order equation, indicating that the chemical adsorption was a rate-limiting step. The calculated thermodynamic parameters (ΔG, ΔH, ΔS) stated that the adsorption of U(VI) onto PS-1.0G PAMAM-PPA were spontaneous, endothermic and feasible. The adsorption isotherms obeyed the Langmuir isotherm models. The desorption studies showed that PS-1.0G PAMAM-PPA could be used repeatedly and adsorption and desorption percentage did not have any noticeable loss after 27 cycles in a fixed bed.

Medical treatment for a fish bone-induced ileal micro-perforation: a case report.

Ingested fish bone induced intestinal perforations are seldom diagnosed preoperatively due to incomplete patient history taking and difficulties in image evidence identification. Most literature suggests early surgical intervention to prevent sepsis and complications resulting from fish bone migrations. We report the case of a 44-year-old man suffered from acute abdomen induced by a fish bone micro-perforation. The diagnosis was supported by computed tomography (CT) imaging of fish bone lodged in distal ileum and a history of fish ingestion recalled by the patient. Medical treatment was elected to manage the patient's condition instead of surgical intervention. The treatment resulted in a complete resolution of abdominal pain on hospital day number 4 without complication. Factors affecting clinical treatment decisions include the nature of micro-perforation, the patient's good overall health condition, and the early diagnosis before sepsis signs develop. Micro-perforation means the puncture of intestine wall without CT evidence of free air, purulent peritoneum or abscess. We subsequently reviewed the literature to support our decision to pursue medical instead of surgical intervention.

The effect of Ce doped in Ti/SnO(2)-Sb(2)O(3)/SnO(2)-Sb(2)O(3)-CeO(2) electrode and its electro-catalytic performance in caprolactam wastewater.

Ti/SnO(2)-Sb(2)O(3)/SnO(2)-Sb(2)O(3)-CeO(2) anodes were prepared by brush coating with high temperature oxidation. The anodes were characterized by X-ray diffractometer (XRD), scanning electron microscope and cyclic voltammetry. The surface of the electrode shows more compact and exist shallower mud cracks than the others by coating with 1% Ce to the surface of Ti/SnO(2)-Sb(2)O(3) electrode. The XRD patterns show that as-prepared electrodes are SnO(2) and TiO(2). The electrode with 1% Ce dopant shows the highest efficiency in the electrolysis of caprolactam wastewater. The oxygen evolution potential is about 1.75 V, the removal rate of chemical oxygen demand is 50%, and the biochemical oxygen demand is 353 mg/L for 5 h at a current of 0.12 A.

Bilateral superficial cervical plexus block combined with general anesthesia administered in thyroid operations.

BACKGROUND: We investigated the analgesic efficacy of bilateral superficial cervical plexus block in patients undergoing thyroidectomy and to determine whether it reduces the adverse effects of general anesthesia. METHODS: We prospectively recruited 162 patients who underwent elective thyroid operations from March 2006 to October 2007. They were randomly assigned to receive a bilateral superficial cervical block (12 ml per side) with isotonic saline (group A; n = 56), bupivacaine 0.5% (group B; n = 52), or levobupivacaine 0.5% (group C; n = 54) after induction of general anesthesia. The analgesic efficacy of the block was assessed with: intraoperative anesthetics (desflurane), numbers of patients needing postoperative analgesics, the time to the first analgesics required, and pain intensity by visual analog scale (VAS). Postoperative nausea and vomiting (PONV) for 24 h were also assessed by the "PONV grade." We also compared hospital stay, operative time, and discomfort in swallowing. RESULTS: There were no significant differences in patient characteristics. Each average end-tidal desflurane concentration was 5.8, 3.9, and 3.8% in groups A, B, and C, respectively (p < 0.001). Fewer patients in groups B and C required analgesics (A: B: C = 33:8:7; p < 0.001), and it took longer before the first analgesic dose was needed postoperatively (group A: B: C = 82.1:360.8:410.1 min; p < 0.001). Postoperative pain VAS were lower in groups B and C for the first 24 h postoperatively (p < 0.001). Incidences of overall and severe PONV were lower, however, there were not sufficient numbers of patients to detect differences in PONV among the three groups. Hospital stay was shorter in group B and group C (p = 0.011). There was no significant difference in operative time and postoperative swallowing pain among the three groups. CONCLUSIONS: Bilateral superficial cervical plexus block reduces general anesthetics required during thyroidectomy. It also significantly lowers the severity of postoperative pain during the first 24 h and shortens the hospital stay.

Compositions and in vitro anticancer activities of the leaf and fruit oils of Litsea cubeba from Taiwan.

The leaf and fruit essential oils of Litsea cubeba, extracted by hydrodistillation, were assessed for anticancer activities. A total of 53 and 50 compounds were identified, respectively from the leaf and fruit oils, and their yields were 13.9 +/- 0.09% and 4.0 +/- 0.03%, v/w, of the oven-dried materials, respectively. The main compound in the leaf oil was 1,8-cineol, and in the fruit oil, citral. The fruit oil, but not that of the leaf, exhibited cytotoxic activity against human lung, liver and oral cancer cells.

Experience with reversed L-shaped incision for right hemicolectomy combined with liver resection.

BACKGROUND: Various types of incisions have been applied in simultaneous resections of colorectal cancer and synchronous liver metastases. We describe our experience with the reversed L-shaped incision for simultaneous right hemicolectomy and liver resection. METHODS: We applied the reversed L-shaped incision in nine patients who underwent simultaneous right hemicolectomy and right liver resection or left hepatectomy. A reversed L-shaped incision of the abdomen was consisted of midline and transverse incisions with the junction of the umbilicus. The operative field was kept open using Kent retractors. First, right colon mobilization was performed easily and right hemicolectomy was performed. Subsequently, liver mobilization with identification of hepatic vessels was achieved and right liver resection or left hepatectomy was performed. RESULTS: The reversed L-shaped incision successfully provided a good and rapid exposure in nine patients. There were no complications, such as wound infection, lung atelectasis/pneumonia, or incisional hernia, in patients with the reversed L-shaped incision. CONCLUSIONS: Our preliminary experience demonstrated that the reversed L-shaped incision might be a good choice in a subset of patients with simultaneous right hemicolectomy and right liver resection or left hepatectomy. However, a large, prospective, controlled study comparing different incision types in the same procedure with variables, such as operating time, postoperative pain scores, patient's satisfaction, and postoperative complication, is needed to support the benefit of the reversed L-shaped incision.

Transection of the esophagus is optional in the Modified Sugiura procedure.

BACKGROUND/AIMS: Esophageal transection in the Modified Sugiura procedure is advocated by some authors, but considered unnecessary by others. We compared the effectiveness of the Modified Sugiura procedure to our simplified Sugiura procedure that omits esophageal transection for the emergency treatment of bleeding esophagogastric varices. METHODOLOGY: From January 1999 to September 2004 we treated 51 patients with cirrhosis of the liver and bleeding esophagogastric varices. All patients had failed management with emergency endoscopy treatment or balloon tamponade with vasopressin infusion. The patients were randomly divided into two groups and underwent the Modified Sugiura procedure with or without esophageal transections. RESULTS: There were no significant differences in age, gender, cause of cirrhosis, or Child-Pugh classification between the two groups. The preoperative hemoglobin levels, preoperative and intraoperative transfusion volume, mortality, morbidity, and days of hospitalization showed no significant differences between the groups. The operative time was shorter with the simplified Sugiura procedure. The 1-3 year survival rates and the rebleeding rates did not differ significantly between the two groups. CONCLUSION: Both treatments are effective emergency procedures for bleeding esophagogastric varices. Our simplified Sugiura procedure is an effective treatment for bleeding esophagogastric varices and requires a shorter operating time than the Modified Sugiura procedure.