Hydrogen iodide (HI) neutral beam etching characteristics of InGaN and GaN for micro-LED fabrication.

We investigated the etching characteristics of hydrogen iodide (HI) neutral beam etching (NBE) of GaN and InGaN and compared with Cl2NBE. We showed the advantages of HI NBE versus Cl2NBE, namely: higher InGaN etch rate, better surface smoothness, and significantly reduced etching residues. Moreover, HI NBE was suppressed of yellow luminescence compared with Cl2plasma. InClxis a product of Cl2NBE. It does not evaporate and remains on the surface as a residue, resulting in a low InGaN etching rate. We found that HI NBE has a higher reactivity with In resulting in InGaN etch rates up to 6.3 nm min-1, and low activation energy for InGaN of approximately 0.015 eV, and a thinner reaction layer than Cl2NBE due to high volatility of In-I compounds. HI NBE resulted in smoother etching surface with a root mean square average (rms) of 2.9 nm of HI NBE than Cl2NBE (rms: 4.3 nm) with controlled etching residue. Moreover, the defect generation was suppressed in HI NBE compared to Cl2plasma, as indicated by lower yellow luminescence intensity increase after etching. Therefore, HI NBE is potentially useful for high throughput fabrication ofµLEDs.

Laparoscopic excision for small intestinal mesenteric tumour diagnosed Schloffer tumour.

This report presents a case of Schloffer tumour at the small intestinal mesentery, mimicking a malignant tumour, treated laparoscopically. Six years prior, a 57-year-old woman underwent laparoscopic salpingo-oophorectomy for a benign, cystic, ovarian tumour, but she had no history of malignancy. She was treated at an outpatient clinic for gastrointestinal complaints and was relieved of these symptoms. Abdominal computed tomography showed an incidental mesenteric tumour of the small intestine, tending toward growth. Due to the tumour's malignant potential, laparoscopic examination was performed. A spherical tumour with a base in the jejunum mesentery was observed. It was removed without damage. The post-operative course was uneventful, and the patient was discharged 3 days after the operation without complications. Histological diagnosis showed this to be a Schloffer tumour, but no malignancy was observed. Unidentified intraperitoneal tumours in patients with surgical histories may be Schloffer tumours, and this should be kept in mind.

Inhibition of enamel demineralization by an ion-releasing tooth-coating material.

PURPOSE: To evaluate the inhibitory effect of a surface pre-reacted glass-ionomer (S-PRG) filler-containing tooth-coating material on enamel demineralization. The outer surface of the S-PRG filler is in a state in which ions are readily released. METHODS: Human enamel blocks were incubated in lactic acid solution (pH 4.0) with and without a disk (n=6) made of the cured tooth-coating material. Test solutions were changed every 24 hours and incubation was continued for 4 days. The pH and amount of fluoride released were measured with an electrode and ion meter, respectively. The concentrations of ions (aluminum, boron, calcium, phosphorus, silicon, sodium, and strontium) were measured by inductively coupled plasma atomic emission spectroscopy. The surface of the enamel block was observed with a scanning electron microscope. RESULTS: Enamel demineralization was not observed in an enamel block incubated with a disk of the tooth-coating material. Ions released from S-PRG filler had an acid buffering action in the low pH lactic acid solution. However, in the enamel block-only solution showing high levels of calcium ion release, the degree of demineralization was correlated with morphological changes of the enamel surface. CLINICAL SIGNIFICANCE: Due to the buffering effects of the pre-reacted glass-ionomer surface by ion release, the S-PRG filler-containing tooth-coating material inhibited enamel demineralization by neutralizing the acidic environment at an early time point.

A 0.8-cm clear cell neuroendocrine tumor G1 of the gallbladder with lymph node metastasis: a case report.

BACKGROUND: Neuroendocrine tumors (NETs) of the gallbladder are rare and generally considered low-grade malignancies. We herein describe a case of a patient with a 0.8-cm clear cell NET G1 of the gallbladder with nodal involvement. CASE PRESENTATION: A 65-year-old man with no medical history indicative of von Hippel-Lindau (VHL) disease underwent laparoscopic cholecystectomy for cholecystolithiasis. There was a 0.8-cm tumor in the neck of the gallbladder. Histologic examination revealed nests or trabecular growth of clear cells with small round-to-oval nuclei. Immunohistochemically, tumor cells showed positivity for chromogranin A and synaptophysin; Ki-67 index was < 1.0%. Based on the World Health Organization 2010 classification, we made a diagnosis of clear cell variant of NET G1 without VHL disease. The tumor invaded the muscular layer and had no extension to the perimuscular connective tissue but had metastasized to a cystic duct node. A radical second resection with regional lymphadenectomy of the gallbladder was performed, and there was no metastasis on histology. After the definitive surgery, he was followed up for 10 months without adjuvant therapy and is alive and well with no evidence of recurrence. CONCLUSIONS: Our experience suggests that, even when smaller than 1 cm, NET G1 of the gallbladder can metastasize. When NET G1 is incidentally identified in the gallbladder of a surgical specimen, detailed pathologic examination of the cystic duct node, when found, should be performed to guide whether a radical second resection with regional lymphadenectomy is appropriate.

[A Case of Locally Advanced Neuroendocrine Carcinoma of the Stomach Could be Curably Resected after Chemotherapy with CPT-11/CDDP].

A 64-year-old man was admitted to our hospital because of epigastralgia. Gastrointestinal endoscopyrevealed a submucosal tumor with ulceration in the upper bodyof the stomach. The tumor was histologicallydiagnosed as a neuroendocrine carcinoma. CT showed that the tumor had directlyinfiltrated the pancreas and splenic vessels. The patient underwent onlyan exploratorylaparotomybecause the tumor seemed to involve the celiac artery. Chemotherapywas conducted using CPT-11/ CDDP. After 15 courses of chemotherapy, a significant tumor reduction was obtained. We performed total gastrectomy with D2 lymphadenectomy, distal pancreatectomy and splenectomy. Histopathological examination of surgical specimens showed that onlyfew carcinoma cells remained in the stomach and pancreas. Neoadjuvant chemotherapycan be a useful treatment for unresectable locallyadvanced neuroendocrine carcinoma of the stomach.

[Surgical Resection after Gemcitabine plus Cisplatin Chemotherapy for Intrahepatic Cholangiocarcinoma with Multiple Lymph Node Metastases - Report of a Case].

An 82-year-old man with upper abdominal pain was referred to our hospital because of an elevated serum CEA level and dilatation of the intrahepatic bile ducts on ultrasonography.Computed tomography revealed a hypovascular mass measuring 5.0 cm in size in the lateral section, dilatation of the peripheral intrahepatic bile ducts, and swollen lymph nodes around the lesser curvature of the stomach, the common hepatic artery, and the paraaorta.He was diagnosed with unresectable intrahepatic cholangiocarcinoma, and he received chemotherapy with biweekly gemcitabine plus cisplatin.After 33 courses of the chemotherapy, computed tomography revealed that the tumor size decreased over 63%, and all swollen lymph nodes had almost resolved.He underwent a left hemihepatectomy 1 year 6 months after the start of the chemotherapy.He remains alive and well with no evidence of recurrence, 11 months after resection.

[Two Episodes of Colostomy-Associated Intestinal Perforation during Chemotherapy for Metastatic Rectal Cancer].

A 77-year-old woman with rectal cancer and synchronous liver metastasis underwent a Hartmann operation with D3 lymph node dissection in June 2014. mFOLFOX6 plus bevacizumab(bev)was then administered to treat the liver metastasis.In February 2015, multiple liver metastases were detected and the regimen was changed to FOLFIRI plus bev.After 3 courses, peritonitis due to intestinal perforation around the descending colostomy occurred, and an emergency operation(partial resection of the descending colon and transverse colostomy)was performed.FOLFIRI was then administered from 2 months after the operation.After 3 courses of this regimen, a CT scan showed progression of the hepatic metastases.The regimen was therefore changed to mFOLFOX6.Five months later, another CT scan showed an intestinal perforation of the transverse colostomy at the abdominal wall, and an emergency cecostomy was performed.At this stage, chemotherapy was ceased.This case highlights the risk of intestinal perforation during chemotherapy, regardless of the use of bev.

Inhibition of enamel demineralization and bond-strength properties of bioactive glass containing 4-META/MMA-TBB-based resin adhesive.

We investigated the enamel demineralization-prevention ability and shear bond strength (SBS) properties of 4-methacryloxyethyl trimellitic anhydride/methyl methacrylate-tri-n-butyl borane (4-META/MMA-TBB)-based resin containing various amounts (0-50%) of bioactive glass (BG). Disk-shaped specimens were immersed in distilled water and ions released were analysed by inductively coupled plasma atomic-emission spectroscopy. Samples were also immersed in lactic acid solution (pH 4.6) to estimate acid-neutralizing ability. Brackets were bonded to human premolars with BG-containing resins and the bonded teeth were alternately immersed in demineralizing (pH 4.55) and remineralizing (pH 6.8) solutions for 14 d. The enamel hardness was determined by nanoindentation testing at twenty equidistant distances from the external surface. The SBS for each sample was examined. The amounts of ions released [calcium (Ca), sodium (Na), silicon (Si), and boron (B)] and the acid-neutralizing ability increased with increasing BG content. After alternating immersion, the specimens bonded with the BG-containing resin with high BG content were harder than those in the other groups in some locations 1-18.5 µm from the enamel surface. Bioactive glass-containing (10-40%) resin had bond strength equivalent to the control specimen. Thus, the SBS obtained for BG-containing resin (6.5-9.2 MPa) was clinically acceptable, suggesting that this material has the ability to prevent enamel demineralization.

Inhibition of enamel demineralization by buffering effect of S-PRG filler-containing dental sealant.

The buffering capacity and inhibitory effects on enamel demineralization of two commercially available dental sealants were evaluated in this study. The effects of filler particles were also examined. Disks of enamel and cured sealant materials of BeautiSealant (silica or S-PRG filler) or Teethmate F-1 were incubated in lactic acid solutions (pH 4.0) for 1-6 d. The pH changes and amounts of ions released in the solutions were assessed, and enamel surfaces were observed using a scanning electron microscope. The pH of the solution with BeautiSealant (S-PRG filler) was neutralized from pH 4.0 to pH 6.1 (after incubation for 1 d) and from pH 4.0 to pH 6.7 (after incubation for 6 d). In addition, no release of calcium ions was detected and the enamel surface was morphologically intact in scanning electron microscopy images. However, the pH of the solution with Teethmate F-1 remained below pH 4.0 during incubation from days 1 to 6. Calcium release was increased in solutions up to and after 6 d of incubation. Scanning electron microscopy images showed that the structures of hydroxyapatite rods were exposed at the specimen surfaces as a result of demineralization. Ions released from S-PRG filler-containing dental sealant rapidly buffered the lactic acid solution and inhibited enamel demineralization.

Bioactive Self-Polymerizing Resin with Surface Pre-Reacted Glass Ionomer Fillers for Suppressed Enamel Demineralization.

The treatment of damaged enamel surfaces involves modification of the enamel surface with artificial materials or the development of a pseudo-enamel, with research focusing on bioactive and biomimetic materials. In this study, a bioactive auto-polymerizing resin (APR) was developed by adding surface-pre-reacted glass ionomer (S-PRG) fillers of different quantities to APR. Its bioactive effects were evaluated via pH neutralization, ion release, and inhibition of enamel demineralization studies. The pH and fluoride ion release were measured using ion-specific electrodes, revealing that the APR disk with the S-PRG filler immediately neutralized the lactic acid solution (pH 4.0) through ion release. Inductively coupled plasma atomic emission spectrometry revealed that the Sr ion release peaked on the first day, with the other ions following the order F > B > Si > Al > Na, exhibiting a weekly decrease in the same order. Scanning electron microscopy was used to examine the enamel block morphology of the disks after 7 d of incubation, revealing enamel demineralization in disks without the S-PRG filler, whereas no demineralization occurred in disks with the S-PRG filler. APR containing the S-PRG filler demonstrated acid buffering suppressed enamel demineralization and bioactive properties.

Frictional and mechanical properties of diamond-like carbon-coated orthodontic brackets.

This study investigated the effects of a diamond-like carbon (DLC) coating on frictional and mechanical properties of orthodontic brackets. DLC films were deposited on stainless steel brackets using the plasma-based ion implantation/deposition (PBIID) method under two different atmospheric conditions. As-received metal brackets served as the control. Two sizes of stainless steel archwires, 0.018 inch diameter and 0.017 × 0.025 inch cross-section dimensions, were used for measuring static and kinetic friction by drawing the archwires through the bracket slots, using a mechanical testing machine (n = 10). The DLC-coated brackets were observed with a scanning electron microscope (SEM). Values of hardness and elastic modulus were obtained by nanoindentation testing (n = 10). Friction forces were compared by one-way analysis of variance and the Scheffé test. The hardness and elastic modulus of the brackets were compared using Kruskal-Wallis and Mann-Whitney U-tests. SEM photomicrographs showed DLC layers on the bracket surfaces with thickness of approximately 5-7 µm. DLC-coated brackets deposited under condition 2 showed significantly less static frictional force for the stainless steel wire with 0.017 × 0.025 inch cross-section dimensions than as-received brackets and DLC-coated brackets deposited under condition 1, although both DLC-coated brackets showed significantly less kinetic frictional force than as-received brackets. The hardness of the DLC layers was much higher than that of the as-received bracket surfaces. In conclusion, the surfaces of metal brackets can be successfully modified by the PBIID method to create a DLC layer, and the DLC-coating process significantly reduces frictional forces.

Effect of photofunctionalization on titanium bone-implant integration in ovariectomized rats.

Osteoporosis is considered a risk factor for osseointegration during implant treatment. Photofunctionalization of titanium has been shown to improve bone-based cell adhesion, proliferation, and functional expression, increasing the bone-implant contact rate and bone-implant integration strength. This study aimed to test the hypothesis that photofunctionalization is effective for implant fixation using an osteoporosis rat model. In the biomechanical push-in test, the bone-implant integration strength of the photofunctionalization treatment group was 1.53 times that of the control group (p<0.05). These values implied that photofunctionalization restored the ovariectomy-induced low bone-implant integration strength to normal states. In the micro-CT analysis, the BV/TV of the photofunctionalization treatment group was 1.32 times that of the control group (p<0.05). These values implied that photofunctionalization restored the ovariectomy-induced low peri-implant bone formation to normal states. These results indicate that photofunctionalization treatment increased peri-implant bone formation and bone-implant integration strength in ovariectomized rats.

Surface analysis of titanium disks with strontium coating.

Peri-implantitis is one of the most common complications after dental implant placement. Researchers have demonstrated that the peri-implantitis tends to occur around dental implants with a rough surface rather than those with a smooth surface. We aimed to investigate the ability of a smooth titanium (Ti) surface containing strontium (Sr) to enhance bone formation as a result of strontium's capacity to support osteoblast proliferation and differentiation. A thin titanium oxide film was formed on an as-mirror polished Ti surface by dipping in 5% sodium hypochlorite (NaOCl) solution for 24 h, followed by thermal treatment at 350°C. The Ti surface was then treated with 1% strontium nitrate (Sr(NO3)2) solution and turned in spin coater. The surface morphology, chemical composition, and release of strontium ions (Sr2+) were evaluated. The results demonstrate that strontium in the form of Sr2+ was successfully doped into the titanium dioxide (TiO2) film by this simple chemical treatment.

Clostridium perfringens sepsis after pancreatoduodenectomy: a case report.

BACKGROUND: Clostridium perfringens sepsis associated with massive intravascular hemolysis has an extremely poor prognosis. We here report a case of C. perfringens sepsis associated with massive intravascular hemolysis that developed secondary to a post-pancreaticoduodenectomy (PD) hepatic abscess. CASE PRESENTATION: A 70-year-old man with Type 2 diabetes underwent PD for an ampulla of Vater carcinoma. His postoperative course was uneventful. He was discharged on the 16th post-operative day (POD 16) after confirming no major abnormalities on abdominal contrast computed tomography (CT) on POD 14 or laboratory results on POD 16. Two days after discharge, he was readmitted because of fever and chills. Laboratory tests showed only a mild inflammatory reaction (white blood cell count, 11,980/mm3; C-reactive protein, 2.07 mg/dL). Abdominal CT showed an irregular, approximately 20-mm diameter, low-density area in the liver S6 region that had not been seen on a recent previous scan. We initially suspected postoperative cholangitis associated with biliary reconstruction and started empirical treatment with sulbactam/ampicillin after drawing blood for culture. Eight hours after admission, he developed septic shock with body temperature 40.0 â„ƒ and blood pressure 70/40 mm Hg. Laboratory findings showed a severe inflammatory reaction, severe anemia, and massive hemolysis (white blood cell count, 37,400/mm3; hemoglobin, 7.7 g/dL; total bilirubin, 8.05 mg/dL; direct bilirubin, 2.66 mg/dL; and lactate dehydrogenase, 1686 U/L). Hemoglobinuria was noted in the urinary catheter output. Repeat CT 9 h after admission showed the low-density area in S6 had become a gas-forming abscess. C. perfringens sepsis was strongly suspected on the basis of these findings and the abscess was drained percutaneously immediately after its diagnosis. His vital signs improved dramatically and he recovered within 24 h. Blood and abscess cultures grew C. perfringens 4 days after admission, leading to a definitive diagnosis of C. perfringens sepsis associated with massive intravascular hemolysis. He was discharged 18 days after admission. His sepsis has not recurred. CONCLUSIONS: Clostridium perfringens infection should be considered in patients who have undergone PD and present with gas-forming hepatic abscesses and/or sepsis associated with intravascular hemolysis. Prompt aggressive treatment is crucial, because C. perfringens infections can cause death within hours.

Bonding of self-etching adhesives on dehydrated dentin.

PURPOSE: This study examined the effect of dentin pretreatment with acetone or ethanol on bonding of one-bottle self-etching vs two-step self-etching adhesives to evaluate the effect of hydration on bond strength. MATERIALS AND METHODS: The bond strengths of resins were measured using two one-bottle and two two-step selfetching adhesives that bonded to wet dentin (control), or acetone- or ethanol-pretreated dentin. Wet dentin is the normal substrate for bond testing, and in the pretreatment groups, 95% acetone or ethanol was applied to the dentin surface for 30 s before bonding. Weight of resin adhesives before and after evaporation was measured to evaluate the extent of the solvent contents in the adhesives. Furthermore, phase separation of adhesives was morophologically investigated by in situ light-microscopic observation to evaluate the hydrophilicity of the adhesive resins. RESULTS: The bond strengths of the acetone and ethanol groups for one-bottle adhesives were significantly greater than for the control (p < 0.05). However, significantly lower bond strengths were found in the pretreatment groups for the two-step self-etching adhesives (p < 0.05). CONCLUSION: The bond strength depended on the wetness of the bonding substrate for both adhesive groups, with a positive effect in bond strength for one-bottle adhesives and a negative effect for two-bottle self-etching adhesives. The acetone- or ethanol-pretreated dentin surfaces may provide an improved substrate for resin adhesion of hydrophilic self-etching adhesives such as one-bottle self-etching adhesives due to dentin dehydration.

Chemical interaction of 4-META with enamel in resin-enamel bonds.

X-ray photoelectron spectroscopy (XPS) is used to analyze 4-META resin and enamel that are debonded at an adhesive interface. The XPS spectra showed two chemical states for Ca: one resulted from Ca of hydroxyapatite and the other, an unknown chemical state, suggested that Ca was chemically bonded with 4-META. We postulate that for a chemical reaction of 4-META and hydroxyapatite, the chemical structure of carboxyl groups will resemble that of calcium phthalate. Hence, calcium phthalate was used as a reference material. Additionally, the spectra obtained from the adhesive interface and the mixture of calcium phthalate with hydroxyapatite particles were compared using peak deconvolution analysis. XPS analysis revealed that the chemical bond of 4-META with enamel resembled the chemical state of Ca in calcium phthalate. Consequently, we suggest that Ca of the enamel and the carboxyl group of 4-META were chelate-bonded at the interface.

In vitro evaluation of NaOCl-mediated functionalization of biologically aged titanium surfaces.

The aim of this study was to evaluate the NaOCl-mediated biofunctionalization of titanium surfaces. Titanium disks stored for 2 weeks were immersed in 5% NaOCl solution for 24 h. A disk immersed in distilled water for 24 h was used as a control. X-ray photoelectron spectrometer assay of the titanium surface after NaOCl treatment demonstrated that organic contaminants containing carbon and nitrogen were removed and the number of hydroxyl groups increased. The NaOCl treatment substantially converted the titanium surface to superhydrophilic status (θ<5°), which resulted in an increased number of attached cells and enhanced cell spreading on the NaOCl-treated surfaces. These results indicate that biofunctionalization of the biologically degraded titanium surfaces can be achieved by chemical surface treatment with 5% NaOCl. The mechanism for desorption of strongly adsorbed organic molecules with polar groups such as amino and aldehyde groups from titanium surfaces by ClO- was elucidated.

Measurements of volatile compound contents in resins using a moisture analyzer.

The contents of volatile adhesive compounds, such as water, solvents, and residual unpolymerized monomers, affect the integrity and durability of adhesive bonding. However, there is no method available that can be used to rapidly assess the residual solvent or water contents of adhesive resins. This study examined the effectiveness of a digital moisture analyzer to measure the volatile compound contents of resins. Five self-etching adhesives and seven experimental light-cured resins prepared with different contents (0, 10, and 20% by weight) of water or solvents (acetone and ethanol) were examined in this study. The resins were prepared using different methods (with and without air blast or light-curing) to simulate the clinical conditions of adhesive application. Resin weight changes (% of weight loss) were determined as the residual volatile compound contents, using the moisture analyzer. After the measurements, the resin films were examined using a scanning electron microscope. The weight changes of the resins were found to depend on the amount of water or solvents evaporating from the resin. Water and solvents were evaporated by air blast or light-curing, but some of the water and solvents remained in the cured resin. The moisture analyzer is easy to operate and is a useful instrument for using to measure the residual volatile compound contents of adhesive resin.

Crystal growth by restorative filling materials.

This study examined the activity and ability of materials to mineralize teeth in gaps, simulating microleakage between the materials and teeth. Three restorative materials (two glass ionomer cements and a compomer) were used in this study. Cured disks of restoratives were placed over flat human tooth surfaces (enamel and dentin), separated by a standardized 20-µm interfacial space, and stored in water for 24 h or 1 yr. After the water-storage period, the materials were detached from the teeth and the opposing surfaces were examined by scanning electron microscopy (SEM) and electron probe micro analysis (EPMA).Hemispherical-shaped precipitations, composed of minute semicircle plate-like crystals, were observed by SEM on the enamel surface after 1 yr of water storage for glass ionomer cement. The amount of crystal growth with the chemical-cured type of glass ionomer cement was greater than with the dual-cured type of glass ionomer cement. However, there was no crystal formation in the compomer. Moreover, no structural changes were observed on dentin surfaces for any material in water after 1 yr. The elements detected in the crystals by EPMA were calcium (Ca), phosphorus (P), and aluminum (Al). The two glass ionomer cements tested have the ability to induce crystals whose composition might be derived from cured glass ionomers.

Ten-years degradation of resin-dentin bonds.

The purpose of this study was to evaluate the durability of resin-dentin bonds in 10-yr water-storage testing. Resin-dentin bonded bulk specimens were prepared using six commercially available resin adhesives. The resin-dentin bonded specimens were stored in water for 24 h (control group) or for 10 yr (experimental groups). After each storage period, the specimens were sectioned to make specimen beams and then subjected to a microtensile bond test. After the bond test, fractured surfaces were examined by scanning electron microscopy (SEM). In addition, interfacial observation of silver nanoleakage was performed using the backscatter electron mode of SEM. The bond strengths of four of the six adhesive systems tested decreased significantly after 10 yr. However, no significant bond-strength reduction was recorded for the other two systems. The interfacial observations showed water tree propagation in the bonding resin layer as a typical morphological change after aging for five of the six adhesives tested. Water tree propagation may be a symptom of degradation in the resin bonding layer of resin-dentin bonds.