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Core-shell GaInN/GaN multiquantum shell (MQS) nanowires (NWs) are gaining great attention for high-efficiency micro-light-emitting diodes (micro-LEDs) owing to the minimized etching region on their sidewall, nonpolar or semipolar emission planes, and ultralow density of dislocations. In this study, we evaluated the changes in NW morphologies and the corresponding device properties induced by GaInN/GaN superlattice (SL) structures. The cathodoluminescence intensities of the samples with 20 and 40 pairs of SLs were about 2.2 and 3.4 times higher, respectively, than that of the sample without SLs. The high-resolution scanning transmission electron microscopy (STEM) inspection confirmed that the high growth temperature of SLs prevented growth in the semipolar plane region close to the n-GaN core. A similar phenomenon was also observed for the GaN quantum barriers of the semipolar MQS region under a high growth temperature of 810 °C. This phenomenon was ascribed to the passivation of the semipolar plane surface by hydrogen atoms and the high probability of decomposition through NH

GaInN/GaN multi-quantum-shell (MQS) nanowires (NWs) are gaining increasing attention as promising materials for developing highly efficient long-wavelength micro-light emitting diodes (LEDs). To improve the emission properties in GaInN/GaN MQS NWs, it is necessary to suppress the emission from the (0001) c-plane MQS at the apex region, which featured with low crystalline quality. In this study, we investigated the enhancement of optical properties and the realization of micro-LEDs by confirming the effect of the (0001) plane region. A 7.9-fold enhancement of the electroluminescence (EL) intensity was demonstrated by removal the (0001) plane region via inductively coupled plasma (ICP) dry etching, owing to the promoted current injection into the (1–101) semi-polar and (10–10) non-polar sidewall area. To investigate the effect of the emission area on the samples with and without truncated (0001) plane region, devices with three different mesa areas (50 × 50, 100 × 100, and 100 × 200 μm2) were fabricated. An increased EL intensity with the reduced mesa areas was observed in the samples without dry etching of the (0001)-plane area, because more current can be injected into the sidewall region with higher crystalline quality and luminous efficiency than the (0001)-plane MQS. Under the same injection current density, the truncated samples’ light output was increased for more than ten times as compared to the samples without (0001)-plane etching. Therefore, it confirms the possibility of realizing highly efficient GaInN/GaN MQS NWs LEDs by eliminating the (0001) plane MQS region. A precise etching and surface passivation of the apex region is expected to further reduce the reverse leakage current and improve the performance in NW-LEDs.

Although surgical resection is the only available treatment to achieve long-term survival in biliary tract cancer, many cases are often identified at an advanced stage at the time of diagnosis. Radiotherapy may be an alternative option to prolong survival in cases with locally advanced unresectable disease. While there are some reports of long-term survival after radiotherapy for unresectable biliary tract cancer, it is rare that clinical symptoms are exhibited by peritoneal dissemination more than 8 years after radiotherapy and that resection can be performed. Our case was a 55-year-old female who had visited with a complaint of jaundice and was diagnosed with primary unresectable hilar cholangiocarcinoma. She received definitve chemoradiotherapy, and repeated receiving maintenance chemotherapy thereafter until clinical manifestation. During follow-up, she was diagnosed with stenosis of the sigmoid colon, which was attributed to peritoneal dissemination of cholangiocarcinoma. We herein report a rare case of primary unresectable hilar cholangiocarcinoma after chemoradiotherapy which was followed by chemotherapy that was controlled for more than 8 years but eventually caused colonic obstruction attributed to peritoneal dissemination.

Background The role of recurrence-free survival (RFS) as a valid surrogate endpoint for overall survival (OS) in patients who underwent upfront surgery for colorectal liver metastases remains uncertain. The aim of the study was to compare the two survival measures in a nationwide cohort of upfront resected colorectal liver metastasis. Methods Data from patients with colorectal liver metastases without extrahepatic metastases who underwent curative surgery for liver metastases were retrieved from the Japanese nationwide database (data collection 2005–2007 and 2013–2014). RFS, OS, and survival after recurrence were estimated using the Kaplan–Meier method. The correlation (ρ) between RFS and OS was assessed using the rank correlation method combined with iterative multiple imputation, to account for censoring. As a secondary analysis, the correlation was evaluated according to adjuvant chemotherapy regimen. In sensitivity analysis, the pairwise correlation between RFS and OS was calculated. Results A total of 2385 patients with colorectal liver metastases were included. In the primary analysis, there was a moderately strong correlation between RFS and OS (ρ = 0.73, 95 per cent c.i. 0.70 to 0.76). The strength of the correlation was similar regardless of the adjuvant treatment regimen (oxaliplatin plus 5-fluorouracil: ρ = 0.72, 0.67 to 0.77; 5-fluorouracil alone: ρ = 0.72, 0.66 to 0.76; observation: ρ = 0.74, 0.69 to 0.78). The mean(s.d.) pairwise correlation coefficient between 3-year RFS and 5-year OS was 0.87(0.06). Conclusion In surgically treated patients with colorectal liver metastases, there was a moderately strong correlation between RFS and OS, which was unaffected by the treatment regimen. Further validation using a trial-level analysis is required.

A 55-year-old woman became aware of a tumor on the left side of the head in July, 2020 and was referred to our hospital in September because of its rapid growth. A head CT showed a neoplastic lesion of the skull. A CT from the neck to the pelvis revealed an ascending colon tumor and multiple lesions in the liver, which was suspected as metastasis. A colonoscopy also showed a type 2 like lesion in the ascending colon, and a biopsy showed adenocarcinoma. A pedunculated polyp had been pointed out in the ascending colon at another hospital four years previously, and the pathological result was an adenoma, but endoscopic mucosal resection was not performed. It is considered that the adenoma became advanced colon cancer with metastasis through the mechanism of multistage carcinogenesis. Metastatic lesions of the ascending colon cancer was suspected with regard to the skull lesion. In addition to the rapid growth, surgical removal was desirable from the viewpoint of cosmetology, and surgery was performed in November. The postoperative pathological diagnosis was a metastatic skull tumor derived from ascending colon cancer. The diagnosis was Stage IVb according to the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma (9

The morphology and crystalline quality of p-GaN shells on coaxial GaInN/GaN multiple quantum shell (MQS) nanowires (NWs) were investigated using metal-organic chemical vapor deposition. By varying the trimethylgallium (TMG) flow rate, Mg doping, and growth temperature, it was verified that the TMG supply and growth temperature were the dominant parameters in the control of the p-GaN shape on NWs. Specifically, a sufficiently high TMG supply enabled the formation of a pyramid-shaped NW structure with a uniform p-GaN shell. The ratio of the growth rate between the c- and m-planes on the NWs was calculated to be approximately 0.4545. High-angle annular dark-field scanning transmission electron microscopy characterization confirmed that no clear extended defects were present in the n-GaN core and MQS/p-GaN shells on the sidewall. Regarding the p-GaN shell above the c-plane MQS region, only a few screw dislocations and Frank-type partial dislocations appeared at the interface between the serpentine c-plane MQS and the p-GaN shell near the tips. This suggested that the crystalline quality of the MQS structure can trigger the formation of screw dislocations and Frank-type partial dislocations during the p-GaN growth. The growth mechanism of the p-GaN shell on NWs was also discussed. To inspect the electronic properties, a prototype of a micro light-emitting diode (LED) with a chip size of 50 × 50 μm2 was demonstrated in the NWs with optimal growth. By correlating the light output curve with the electroluminescence spectra, three different emission peaks (450, 470, and 510 nm) were assignable to the emission from the m-, r-, and c-planes, respectively.

Improving current injection into r- and m-planes of nanowires (NWs) is essential to realizing efficient GaInN/GaN multiple quantum shell (MQS) NW-based light-emitting diodes (LEDs). Here, we present the effects of different p-GaN shell growth conditions on the emission characteristics of MQS NW-LEDs. Firstly, a comparison between cathodoluminescence (CL) and electroluminescence (EL) spectra indicates that the emission in NW-LEDs originates from the top region of the NWs. By growing thick p-GaN shells, the variable emission peak at around 600 nm and degradation of the light output of the NW-LEDs are elaborated, which is attributable to the localization of current in the c-plane region with various In-rich clusters and deep-level defects. Utilizing a high growth rate of p-GaN shell, an increased r-plane and a reduced c-plane region promote the deposition of indium tin oxide layer over the entire NW. Therefore, the current is effectively injected into both the r- and m-planes of the NW structures. Consequently, the light output and EL peak intensity of the NW-LEDs are enhanced by factors of 4.3 and 13.8, respectively, under an injection current of 100 mA. Furthermore, scanning transmission electron microscope images demonstrate the suppression of dislocations, triangular defects, and stacking faults at the apex of the p-GaN shell with a high growth rate. Therefore, localization of current injection in nonradiative recombination centers near the c-plane was also inhibited. Our results emphasize the possibility of realizing high efficacy in NW-LEDs via optimal p-GaN shell growth conditions, which is quite promising for application in the long-wavelength region.

High crystalline quality coaxial GaInN/GaN multiple quantum shells (MQSs) grown on dislocation-free nanowires are highly in demand for efficient white-/micro-light-emitting diodes (LEDs). Here, we propose an effective approach to improve the MQS quality during the selective growth by metal-organic chemical vapor deposition. By increasing the growth temperature of GaN barriers, the cathodoluminescent intensity yielded enhancements of 0.7 and 3.9 times in the samples with GaN and AlGaN spacers, respectively. Using an AlGaN spacer before increasing the barrier temperature, the decomposition of GaInN quantum wells was suppressed on all planes, resulting in a high internal quantum efficiency up to 69%. As revealed by scanning transmission electron microscopy (STEM) characterization, the high barrier growth temperature allowed to achieve a clear interface between GaInN quantum wells and GaN quantum barriers on the c-, r-, and m-planes of the nanowires. Moreover, the correlation between the In incorporation and structure features in MQS was quantitatively assessed based on the STEM energy-dispersive X-ray spectroscopy mapping and line-scan profiles of In and Al fractions. Ultimately, it was demonstrated that the unintentional In incorporation in GaN barriers was induced by the evaporation of predeposited In-rich particles during low-temperature growth of GaInN wells. Such residual In contamination was sufficiently inhibited by inserting low Al fraction (∼6%) AlGaN spacers after each GaInN well. During the growth of AlGaN spacers, AlN polycrystalline particles were deposited on the surrounding dummy substrate, which suppressed the evaporation of the predeposited In-rich particles. Thus, the presence of AlGaN spacers certainly improved the uniformity of In fraction through five GaInN quantum wells and reduced the diffusion of point defects from n-core to MQS active structures. The superior coaxial GaInN/GaN MQS structures with the AlGaN spacer are supposed to improve the emission efficiency in white-/micro-LEDs.

A patient was 70-year-old female. Because unknown fever following operation of left knee in December 20XX-1, abdominal simple CT was performed, diagnosed as cholecystitis and liver abscesses. However, her unknown fever did not improve with antibiotics therapy. Abdominal enhanced CT and MRI revealed to gallbladder cancer with liver invasion and metastases. These lesions were relatively localized in liver S4a/S5 and gallbladder, hepatoduodenal mesentery. Because unknown fever was exhausting, cholecystectomy, S4a+S5 hepatectomy with extrahepatic bile duct resection and lymph node dissemination were performed in January 20XX+1. In these pathological findings, there were moderate to poorly differentiated adenocarcinoma with squamous cell differentiation in almost area of gallbladder, diagnosed as adeno-squamous carcinoma with liver invasion and metastasis(pT3a[SI][H-inf], int, INF-β, ly1, v3, pn1, pN1, pM1, pStage ⅣB). One months after operation, abdominal CT revealed multiple liver metastatic recurrences. She died 7 months after operation. Although gallbladder adeno-squamous carcinoma has a poor prognosis, these many cases had a tendency to local infiltration accompanied with tumor fever. If curative resection might be obtained and the symptoms might be improved, aggressive resection should be performed.

A 69-year-old female underwent a mesh repair for an abdominal incisional hernia 4 years previously in our hospital. She visited local hospital for abdominal pain and fever. Abdominal CT showed a localizes abscess formation above the mesh, then she was taken to our hospital. We suspected mesh infection and performed emergent mesh removal. After the operation, we examined for her anemia. Her colonoscopy and CT findings pointed to transverse colon cancer. We performed right hemicolectomy, and final diagnosis was transverse colon cancer pT4aN0M0, pStage Ⅱb. She underwent adjuvant chemotherapy, and 9 months after surgery, no recurrence was found.

Here, we systematically investigated the growth conditions of an n-GaN cap layer for nanowire-based light emitters with a tunnel junction. Selective-area growth of multiple quantum shell (MQS)/nanowire core-shell structures on a patterned n-GaN/sapphire substrate was performed by metal-organic vapor phase epitaxy, followed by the growth of a p-GaN, an n++/ p++-GaN tunnel junction, and an n-GaN cap layer. Specifically, two-step growth of the n-GaN cap layer was carried out under various growth conditions to determine the optimal conditions for a flat n-GaN cap layer. Scanning transmission electron microscopy characterization revealed that n++-GaN can be uniformly grown on the m-plane sidewall of MQS nanowires. A clear tunnel junction, involving 10-nm-thick p++-GaN and 3-nm-thick n++-GaN, was confirmed on the nonpolar m-planes of the nanowires. The Mg doping concentration and distribution profile of the p++-GaN shell were inspected using three-dimensional atom probe tomography. Afterward, the reconstructed isoconcentration mapping was applied to identify Mg-rich clusters. The density and average size of the Mg clusters were estimated to be approximately 4.3 × 1017 cm-3 and 5 nm, respectively. Excluding the Mg atoms contained in the clusters, the remaining Mg doping concentration in the p++-GaN region was calculated to be 1.1 × 1020 cm-3. Despite the lack of effective activation, a reasonably low operating voltage and distinct light emissions were preliminarily observed in MQS nanowire-based LEDs under the optimal n-GaN cap growth conditions. In the fabricated MQS-nanowire devices, carriers were injected into both the r-plane and m-plane of the nanowires without a clear quantum confinement Stark effect.

Multi-color emission from coaxial GaInN/GaN multiple-quantum-shell (MQS) nanowire-based light-emitting diodes (LEDs) was identified. In this study, MQS nanowire samples for LED processes were selectively grown on patterned commercial GaN/sapphire substrates using metal–organic chemical vapor deposition. Three electroluminescence (EL) emission peaks (440, 540, and 630 nm) were observed, which were primarily attributed to the nonpolar m-planes, semipolar r-planes, and the polar c-plane tips of nanowire arrays. A modified epitaxial growth sequence with improved crystalline quality for MQSs was used to effectively narrow the EL emission peaks. Specifically, nanowire-based LEDs manifested a clear redshift from 430 nm to 520 nm upon insertion of AlGaN spacers after the growth of each GaInN quantum well. This demonstrates the feasibility of lengthening the EL emission wavelength since an AlGaN spacer can suppress In decomposition of the GaInN quantum wells during ramping up the growth temperature for GaN barriers. EL spectra showed stable emission peaks as a function of the injection current, verifying the critical feature of the non-polarization of GaN/GaInN MQSs on nanowires. In addition, by comparing EL and photoluminescence spectra, the yellow-red emission linked to the In-fluctuation and point defects in the c-plane MQS was verified by varying the activation annealing time and lowering the growth temperature of the GaInN quantum wells. Therefore, optimization of MQS nanowire growth with a high quality of c-planes is considered critical for improving the luminous efficiency of nanowire-based micro-LEDs/white LEDs.

GaInN/GaN multiple quantum shells (MQS) nanowires and p-GaN shells were embedded with n-GaN layers through tunnel junction (TJ) shells using metalorganic chemical vapor deposition (MOCVD) method. The MQS nanowires were selectively grown on n-GaN/sapphire or GaN substrates. The fabrication process of laser structures with different resonators of 600500, 750, 1000 μm, and cavity widths of 7, 12, and 17 μm were investigated with insulating layer on the sidewalls of the ridge. The structures of the fabricated devices were characterized by scanning electron microscope (SEM) and current-voltage-light output characteristics were evaluated. Two different methods for mirror formation, etching and cleavage, were developed for the laser devices. During the investigation, a superior mirror formation suffered from the difference in etching rate between GaInN and GaN, generating concaves in the MQS region. Bluegreen light emission was observed from the entire ridge surface of the MQS index-guided laser structures. A maximum current density of emission at 17.9 kA/cm2 has been confirmed in the devices. The electroluminescence and cathodoluminescence measurements demonstrated that the r-plane and c-plane at the top of the MQS are dominant at low current densities, and the m-plane emission becomes stronger as the current density increases.

A tunnel junction and a n-GaN cap layer grown on the multi-quantum shells (MQS) /nanowires are introduced to decrease the resistivity and optical loss. The selective-area growth of the MQS/nanowire core-shell structures on the template was performed by metalorganic vapour phase epitaxy (MOVPE). Further, the MQS structure was covered with the tunnel junction and the n-GaN cap layer. Here, the growth conditions of the n-GaN cap layer were systemically investigated. The effect of p-GaN shape on the morphology of grown n-GaN cap layer was also assessed.

The selective-monolithic growth of coaxial GaInN/GaN NWs was investigated by changing the TEG flow rate, barrier and well growth temperature during MQS growth. In incorporation increased with a higher TEG flow rate. However, In-rich flakes were formed the NWs resulting in the deterioration of crystal quality. Using a higher growth temperature of quantum barriers, abnormal growth at the top of NWs was eliminated. As a result, the CL emission intensity was enhanced. Furthermore, the occurrence of In desorption was suppressed by decreasing the growth temperature of quantum wells. Therefore, these results are promising for NW-based white LEDs.

In this study, first-principles calculations were carried out for the first time to systematically investigate the grain boundary segregation of transition metal alloying elements (Ti, V, Cr, Mn, Co, Ni, Cu, Nb, and Mo) in paramagnetic γFe and its dependence on the grain boundary character. The segregation energies of each element and site were comprehensively calculated for nine [0 0 1] symmetric tilt grain boundary models with Σ values from 5 to 41; the paramagnetic state was simulated by the antiferromagnetic double-layer (AFMD). By calculating the effective segregation energy for each grain boundary model from the obtained segregation energies, the grain boundary segregation behavior for each alloying element and its dependence on the grain boundary character were investigated. The segregation energy of transition metal elements is dominated by the Voronoi volume of Fe at the segregation site and arises from the elastic energy derived from the difference in atomic radii between the host and solute metals. Ti, Cu, Nb, and Mo have negative effective segregation energies (indicating a tendency toward segregation) at all investigated grain boundaries, and the absolute values of the effective segregation energy increase in the order of Cu

A 60's woman was admitted to our hospital because of palpitations that occurred with exertion. Coronary angiography computed tomography(CT)of suspected angina detected a tumor in the pancreatic head region. Abdominal CT showed a poorly enhanced 40×32 mm solid tumor in the hepatoduodenal ligament that contained a fatty component and calcification. During surgery, the tumor was located in the hepatoduodenal ligament, adhered to the pancreatic head, common hepatic artery, gastroduodenal artery, portal vein and common bile duct. However, the tumor was resected by preserving them. The tumor contained stratified squamous epithelium, a sebaceous gland, nerve, a pancreatic gland, and an adrenal gland. The histological diagnosis was a mature cystic teratoma. The patient showed no recurrence in 2 years and 10 months post-surgery. Mature teratomas in the hepatoduodenal ligament are extremely rare. Some reports showed that combined resection was performed when the tumor was in contact with the common bile duct, portal vein, and arteries. However, in our case, the tumor was removed relatively safely without combined resection.

The patient was a 79-year-old woman. In January 20XX, upper gastrointestinal endoscopy revealed a duodenal tumor with bleeding and ulceration. This tumor was diagnosed as a duodenal neuroendocrine tumor(NET)based on biopsy findings. In March 20XX, the patient underwent pancreatoduodenectomy with lymph node dissemination. Based on these pathological findings, the tumor was diagnosed as a duodenal NET(G2)with a lymph node metastasis(T2, N1, M0, Stage Ⅲ). Twenty months after the operation, abdominal CT revealed multiple liver metastases(S4, S7, and S8). After this recurrence, she underwent the subcutaneous somatostatin analogue injection therapy every 28 days, and transarterial chemoembolization( TACE)when these recurrent tumors showed remarkable regrowth, once a year, accounting for her age. She has maintained good disease control for 5 years.

An 84-year-old woman with a chief complaint of right lower abdominal pain was admitted to our hospital in November 20XX. Abdominal CT scan revealed a 9.6×4.1 cm diameter low density area proximal to the 13 mm diameter appendix, which led to perforated appendicitis with a huge abscess. The patient underwent an open appendectomy with partial cecum resection. The appendix was found to be twisted by 540°. The pathological diagnosis was low-grade appendiceal mucinous neoplasm(LAMN). Recent research has found that the use of laparoscopic surgery for the treatment of LAMN has been increasing. Appropriate surgical intervention should be considered for LAMN because it is a borderline malignancy. Careful treatment with laparoscopic surgery might be considered as one of the treatment options for LAMN. We hope to accumulate more cases of LAMN to confirm our results.

A 78-year-old woman had undergone subtotal stomach-preserving pancreatoduodenectomy for acinar cell carcinoma (ACC)of the pancreatic head approximately 2 years before presentation, and the pathological diagnosis had been pT2pN0pM0, fStageⅠB(JPS 7th). Adjuvant chemotherapy was discontinued after 3 months because of side effects. Contrast- enhanced CT and PET-CT 2 years postoperatively revealed a tumor measuring 2 cm with a high concentration of FDG in the minor curvature of the stomach. During laparotomy, a 3 cm large lymph node was palpated in the minor curvature of the stomach, and a small lymph node was found adjacently. We diagnosed the patient with multiple lymph node recurrences and performed gastric lymph node dissection of the minor curvature. The pathological diagnosis was a single 2 cm large ACC lymph node metastasis. The patient did not consent to postoperative adjuvant chemotherapy and showed no recurrence for 1 year and 7 months postoperatively. Pancreatic ACC is a rare pancreatic tumor, and its clinicopathologic features are still largely unknown. In recent years, there have been reports of active resection or long-term survival with anti-cancer drug treatment even in recurrent cases, such as the present case. However, the indication and method of anti-cancer treatment are unclear and might need the accumulation of many more cases.

In December 20XX-1, abdominal enhanced CT of a 73-year-old female patient showed a 28mm-in-diameter pancreatic tail cancer with splenic venous invasion. She underwent neoadjuvant GEM/TS-1 combination chemotherapy but abandoned this chemotherapy due to melena and exanthema. She underwent a distal pancreatectomy with lymph node dissemination. In these pathological findings, the tumor was diagnosed as a pancreatic tail cancer with splenic venous invasion(T3, N0, M0, Stage ⅡA). She underwent adjuvant GEM chemotherapy, but she abandoned this chemotherapy due to exanthema and was managed with observation. In September 20XX, she had a postoperative bowel obstruction and was treated with natural light. However, she had a postoperative bowel obstruction again in July, 20XX+1. Fluoroscopic images revealed stenosis in the intestine located 170 cm from the nasal cavity. She underwent open surgery to manage the bowel obstruction. There was a peritoneal tumor with adhesion to each intestine serosa in 3 areas located 80 cm, 100 cm, and 150 cm from the Treitz ligament. Therefore, she underwent a small intestine resection and anastomosis 70 cm to 110 cm from the Treitz ligament. Pathological findings showed that there was a 3mm-in-diameter adenocarcinoma in this peritoneal tumor. In these findings, this final diagnosis was an adhesive intestinal obstruction caused by peritoneal metastasis. Curative resection for single peritoneal recurrent metastasis might be useful for prognosis prolongation.

A 57-year-old woman was diagnosed with advanced gastric cancer with bone marrow metastasis(cT4aN1pM1[MAR], pStage Ⅳ). After 18 courses of S-1 and cisplatin and 18 courses of ramucirumab and paclitaxel, the chemotherapy was stopped because of stenosis. We performed endoscopic metallic stent placement, but stenosis reappeared after a month. Subsequently, distal gastrectomy was performed as a palliative surgery. She had no complications and improved appetite, therefore, she resumed chemotherapy after 3 postoperative months and continued for 4 years and 9 months from the first visit. In general, gastric cancer with bone marrow metastasis has a poor prognosis, however, in this case, long-term survival was achieved with palliative surgery.

Taxanes are applied as potent chemotherapeutic agents in the treatment of patients with esophageal cancer, but their usefulness is limited, partly because of acquisition of chemoresistance. In our previous study, we established three taxane resistant esophageal cancer cell lines; significant ABCB1 upregulations were found in all three. However, the responsible mechanism(s) still remains an open question. In this study, we explored possible mechanisms that might contribute to upregulation of ABCB1 in taxane resistant cells. ABCB1 gene amplification was found in taxane resistant cell line RTE-1P, but expressional upregulation cannot be explained only by gene amplification, because gene amplification is one order of magnitude or less whereas gene expression is more than two orders of magnitude. In the parental TE-1, ABCB1 expression was upregulated after treatment with 5-azadeoxycytidine and/or trichostatin A; epigenetic mechanisms may be deeply involved. ABCB1 has two promoters; a downstream promoter was found to play the dominant role in taxane resistant esophageal cancer cell lines. Analyses of CpG islands demonstrated that taxane resistant cells showed unmethylated CGI whereas parental cells were dominantly methylated. In conclusion, we propose that both the ABCB1 gene amplification and aberrations in epigenetic mechanisms are responsible for acquisition of taxane resistance in esophageal cancer cells.

In this study, the growth mechanisms of n-type gallium nitride (GaN) cap layers for embedding nanowire-based multi-quantum-shell (NW-MQS) with a tunnel junction were investigated using the metal–organic vapor-phase epitaxy method. Herein, instead of a p-type GaN layer, n-type GaN cap layers were applied as a contact layer to the anode electrode via a tunnel junction. NW-MQSs were prepared in a rectangular grid arrangement aligning with the m- and a-axis of GaN. The growth mode of the cap layers was controlled in three stages using different growth pressures and temperatures. The first cap layer was a faceted growth mode primarily comprising the r-plane, the second was a lateral growth mode that expanded the area of the c-plane, and the third was an acceleration of lateral growth. Finally, cap layers with a flat surface were realized. Void formation in the cap layers occurred only between the NW-MQSs along the m-axis of GaN. This observation can be attributed to the difference in the coalescence of the cap layers in the a- and m-axis directions. We believe that the NW-MQS structure with the cap layer that was optimized in this study can be used as a highly efficient optical device.