Ultrafast 2D Nanosheet Assembly via Spontaneous Spreading Phenomenon.

In 2D materials, a key engineering challenge is the mass production of large-area thin films without sacrificing their uniform 2D nature and unique properties. Here, it is demonstrated that a simple fluid phenomenon of water/alcohol solvents can become a sophisticated tool for self-assembly and designing organized structures of 2D nanosheets on a water surface. In situ, surface characterizations show that water/alcohol droplets of 2D nanosheets with cationic surfactants exhibit spontaneous spreading of large uniform monolayers within 10 s. Facile transfer of the monolayers onto solid or flexible substrates results in high-quality mono- and multilayer films with high coverages (>95%) and homogeneous electronic/optical properties. This spontaneous spreading is quite general and can be applied to various 2D nanosheets, including metal oxides, graphene oxide, h-BN, MoS2, and transition metal carbides, enabling on-demand smart manufacture of large-size (>4 inchϕ) 2D nanofilms and free-standing membranes.

Facile Synthesis of Pd Nanosheets and Implications for Superior Catalytic Activity.

As a member of the 2D materials family, 2D metal nanosheets (metallenes) have received increasing attention due to their intriguing properties distinct from those of graphene and other inorganic 2D nanosheets. However, the synthesis of metallenes is still challenging, owing to the lack of an efficient synthetic approach. Here we present a facile one-pot approach to the controlled synthesis of Pd nanosheets. A key feature of this process is a stepwise reaction using 2,4,6-trichlorophenyl formate (TCPF); TCPF emits carbon monoxide gas, which acts as both a reductant and a surface capping agent, promoting the anisotropic 2D growth of the Pd nanosheets. Photoemission spectroscopy revealed some peculiar features of the surface charge and valence band states due to suppressed electron transfer at the 2D surface. This surface state caused improved catalytic activity for the hydrogen evolution reaction compared to that of bulk Pd.

Gigantic Thermal Shielding in 2D Oxide Nanosheets.

Thermal shielding materials that can block near-infrared (NIR) light from the sunlight while maintaining visible transparency have become increasingly important from an energy-saving perspective. Here, we demonstrate a gigantic NIR shielding by an engineered plasmonic material based on a two-dimensional (2D) polytungstate (Cs4-xW11O35-d). Starting from a charge-neutral polytungstate (Cs4W11O35), we synthesize charge-imbalanced 2D nanosheets (Cs4-xW11O35-d) that undergo an unusual structural change with the semiconductor-to-metal transition in a reduced atmosphere. Layer-by-layer engineering of the 2D nanosheets enables a plasmon-induced enhancement of the NIR reflectance (>53%) with a high visible transparency (>71%), realizing high-performance thermal shielding. Our approach offers a solution for future thermal management technology.

Ultrahigh Energy Storage in 2D High-κ Perovskites.

Dielectric capacitors have greater power densities than batteries, and, unlike batteries, they do not utilize chemical reactions during cycling. Thus, they can become ideal, safe energy storage devices. However, dielectric capacitors yield rather low energy densities compared with other energy storage devices such as batteries and supercapacitors. Here, we present a rational approach for designing ultrahigh energy storage capacitors using two-dimensional (2D) high-κ dielectric perovskites (Ca2Nam-3NbmO3m+1; m = 3-6). Individual Ca2Nam-3NbmO3m+1 nanosheets exhibit an ultrahigh dielectric strength (638-1195 MV m-1) even in the monolayer form, which exceeds those of conventional dielectric materials. Multilayer stacked nanosheet capacitors exhibit ultrahigh energy densities (174-272 J cm-3), high efficiencies (>90%), excellent reliability (>107 cycles), and temperature stability (-50-300 °C); the maximum energy density is much higher than those of conventional dielectric materials and even comparable to those of lithium-ion batteries. Enhancing the energy density may make dielectric capacitors more competitive with batteries.

Automated One-Drop Assembly for Facile 2D Film Deposition.

The effective application of 2D materials is strongly dependent on the mass production of high-quality large-area 2D thin films. Here, we demonstrate a strategy for the automated manufacturing of high-quality 2D thin films using a modified drop-casting approach. Our approach is simple; by using an automated pipette, a dilute aqueous suspension is dropped onto a substrate heated on a hotplate, and controlled convection by Marangoni flow and liquid removal causes the nanosheets to come together to form a tile-like monolayer film in 1-2 min. Ti0.87O2 nanosheets are utilized as a model system for investigating the control parameters such as concentrations, suction speeds, and substrate temperatures. We perform the automated one-drop assembly of a range of 2D nanosheets (metal oxides, graphene oxide, and hexagonal boron nitride) and successfully fabricate various functional thin films in multilayered, heterostructured, and sub-micrometer-thick forms. Our deposition method enables on-demand large-size (>2 inchϕ) manufacturing of high-quality 2D thin films while reducing the time and sample consumption.

Free-Standing Molecularly Thin Amorphous Silica Nanosheets.

Recent progress in 2D materials has initiated new fields of molecularly thin amorphous materials with mysterious properties and structures. However, designed synthesis of molecularly thin amorphous silica still remains a challenge; whether free-standing molecularly thin amorphous silica nanosheets can exist is unclear. Here, this issue is addressed by using a new chemical protocol; solid-state surfactant lamellae with ordered alkyl-chain arrangements can serve as superior templates guiding free-standing amorphous silica nanosheets. Simple sonication of the lamellar hybrids allows exfoliation into monolayer amorphous silica nanosheets with 0.9 nm thickness. In addition, the nanosheets show the distinctive feature of high colloidal stability that enables atomic layer engineering of silica nanocoatings and dielectric nanofilms. The approach may shed new light on the properties and applications of old silica.

Damage-free LED lithography for atomically thin 2D material devices.

Desired electrode patterning on two-dimensional (2D) materials is a foremost step for realizing the full potentials of 2D materials in electronic devices. Here, we introduce an approach for damage-free, on-demand manufacturing of 2D material devices using light-emitting diode (LED) lithography. The advantage of this method lies in mild photolithography by simply combining an ordinary optical microscope with a commercially available LED projector; the low-energy red component is utilized for optical characterization and alignment of devices, whereas the high-energy blue component is utilized for photoresist exposure and development of personal computer designed electrode patterns. This method offers maskless, damage-free photolithography, which is particularly suitable for 2D materials that are sensitive to conventional lithography. We applied this LED lithography to device fabrication of selected nanosheets (MoS2, graphene oxides and RuO2), and achieved damage-free lithography of various patterned electrodes with feature sizes as small as 1-2 µm. The LED lithography offers a useful approach for cost-effective mild lithography without any costly instruments, high vacuum, or complex operation.

Tailored synthesis of molecularly thin platinum nanosheets using designed 2D surfactant solids.

The assembly of the surfactants has been utilized as unique templates for the controlled synthesis of metal nanosheets. However, current strategies for metal nanosheets have mainly focused on the liquid-phase surfactant assembly. Herein, we found the solid-state surfactants as designable crystals suitable for nanostructural control and proposed a novel synthetic route for molecularly thin Pt metal nanosheets using solid surfactant crystals as a precursor. The 2D surfactant crystals containing planarly arranged Pt complexes were prepared, and the subsequent UV-ozone treatment and reduction process allowed us to obtain Pt metal nanosheets. Pt metal nanosheets had a distinct morphology with various thicknesses (from 1.5 nm to 3.0 nm), characteristic of 2D surfactant crystals.

AI analysis and modified type classification for endocytoscopic observation of esophageal lesions.

Endocytoscopy (EC) facilitates real-time histological diagnosis of esophageal lesions in vivo. We developed a deep-learning artificial intelligence (AI) system for analysis of EC images and compared its diagnostic ability with that of an expert pathologist and nonexpert endoscopists. Our new AI was based on a vision transformer model (DeiT) and trained using 7983 EC images of the esophagus (2368 malignant and 5615 nonmalignant). The AI evaluated 114 randomly arranged EC pictures (33 ESCC and 81 nonmalignant lesions) from 38 consecutive cases. An expert pathologist and two nonexpert endoscopists also analyzed the same image set according to the modified type classification (adding four EC features of nonmalignant lesions to our previous classification). The area under the curve calculated from the receiver-operating characteristic curve for the AI analysis was 0.92. In per-image analysis, the overall accuracy of the AI, pathologist, and two endoscopists was 91.2%, 91.2%, 85.9%, and 83.3%, respectively. The kappa value between the pathologist and the AI, and between the two endoscopists and the AI showed moderate concordance; that between the pathologist and the two endoscopists showed poor concordance. In per-patient analysis, the overall accuracy of the AI, pathologist, and two endoscopists was 94.7%, 92.1%, 86.8%, and 89.5%, respectively. The modified type classification aided high overall diagnostic accuracy by the pathologist and nonexpert endoscopists. The diagnostic ability of the AI was equal or superior to that of the experienced pathologist. AI is expected to support endoscopists in diagnosing esophageal lesions based on EC images.

[A Case of Papillary Carcinoma of Thyroid Associated with Familial Adenomatous Polyposis in a Younger Woman].

Familial adenomatous polyposis(FAP)is an autosomal dominantly inherited disorder, and the result of a germ line variant in the adenomatous poplyposis coli(APC)gene. FAP can be associated with various extracolonic lesions including thyroid cancer, which frequently occurs in women. We report the case of a 15-year-old woman diagnosed as FAP with multiple thyroid papillary carcinomas. Her mother had been treated for FAP with colorectal cancer and thyroid cancer in our department. Multiple tumors with a maximum diameter of 17 mm were detected in the right lobe of the thyroid gland during the preoperative examination. Papillary carcinoma was suspected based on fine-needle aspiration cytology. She was diagnosed with FAP because of multiple polyps on colonoscopy. We performed a subtotal thyroidectomy. Pathological findings revealed a cribriform-morular variant of papillary thyroid carcinoma. We report a rare case of papillary carcinoma of thyroid associated with FAP in a younger woman.

[Conversion Surgery following Second-Line Chemotherapy for Unresectable Gastric Cancer].

We retrospectively analyzed clinicopathological and survival data of 8 patients with unresectable gastric cancer who underwent conversion surgery(CS)following second-line chemotherapy from April 2013 to December 2020. There were 7 males and 1 female patients with a median age of 69(64-76)years old. Five patients had 1 unresectable factor, 2 had 2 unresectable factors, and 1 had 3 unresectable factors. All patients achieved R0 resection. The median survival time(MST) of patients with CS following second-line chemotherapy was significantly longer than that without CS(73.4 vs 12.3 months, respectively). The MST of patients with CS following first-line chemotherapy was significantly longer than that without CS (22.9 vs 12.3 months, respectively). This study suggested that CS following first- or second-line chemotherapy may improve survival duration for unresectable gastric cancer.

[Two Cases of Esophageal Neuroendocrine Carcinoma That Were Successfully Controlled by Multi-Modality Therapy].

Esophageal neuroendocrine carcinoma is extremely rare, and its treatment strategy has not been established. We report 2 cases esophageal neuroendocrine carcinoma. Case 1: A 74-year-old man was diagnosed as having esophageal neuroendocrine carcinoma(clinical T3N4M0, Stage Ⅳa). He received 60 Gy of radiation therapy with etoposide(100 mg/m2)plus cisplatin(80 mg/m2). No recurrence has been detected 1 year after treatment. Case 2: A 78-year-old man was diagnosed as esophageal neuroendocrine carcinoma(clinical T3N0M0, Stage Ⅱ). He underwent esophagectomy with 3 field lymph nodes dissection. Adjuvant chemotherapy was administered with irinotecan(60 mg/m2)plus cisplatin(60 mg/m2). After chemotherapy, he survived 1 year without recurrence.

[Three Cases of Conversion Surgery for Unresectable Gastric Cancer with Multiple Liver Metastases].

We herein report 3 cases of advanced gastric cancer with multiple liver metastases who was successfully treated with systemic chemotherapy and underwent conversion surgery with liver resection. There were 2 males and 1 female patients with a range 68 to 74 years of age. Two patients received S-1 plus oxaliplatin therapy and 1 received S-1 plus cisplatin therapy. All patients survived after 5-49 months postoperatively.

Preparation of Sub-50 nm Colloidal Monodispersed Hollow Siloxane-Based Nanoparticles with Controlled Shell Structures.

Hollow siloxane-based nanoparticles (HSNs) have attracted significant attention because of their promising unique properties for various applications. For advanced applications, especially in catalysis, drug delivery systems, and smart coatings, high dispersibility and monodispersity of HSNs with precisely controlled shell structures are important. In this study, we established a simple method for preparing colloidal HSNs with a uniform particle size below 50 nm by the reaction of colloidal silica nanoparticles with bridged organoalkoxysilane [1,2-bis(triethoxysilyl)ethylene: (EtO)3Si-C2H2-Si(OEt)3, BTEE] in the presence of a cationic surfactant. Upon the formation of organosiloxane shells by hydrolysis and polycondensation of BTEE, the core silica nanoparticles were spontaneously dissolved, and a part of the silicate species was incorporated into the organosiloxane shells. The size of the colloidal silica nanoparticles, the amount of BTEE added, and the pH of the reaction mixture greatly affected the formation of HSNs. Importantly, colloidal HSNs having micropores and mesopores in the shells were successfully prepared using silica nanoparticles (20, 30, and 40 nm in diameter) at pH values of 9 and 11, respectively. These HSNs are potentially important for applications in drug delivery systems and catalysis.

Endocytoscopic observation with methylene blue staining for duodenal neoplasms associated with familial adenomatous polyposis.

Duodenal cancer is a leading cause of death after colectomy in patients with familial adenomatous polyposis (FAP). Detailed endoscopic evaluation of duodenal lesions with potential for carcinoma development is therefore mandatory. Here we investigated the features of duodenal lesions in FAP patients using an endocytoscopy system (ECS). We retrospectively reviewed duodenal lesions in 15 cases of FAP using an ECS (GIF-H290EC) with methylene blue (MB) as the vital dye. With reference to the Spigelman classification, we investigated the number of lesions using white light (WL), narrow-band imaging (NBI), and MB staining. Using the maximum magnification power of the ECS we investigated the histology (duct openings or finger-like projections) and grade of dysplasia (presence or absence of enlarged oval-shaped nuclei) of the lesions. The number of duodenal lesions increased in ascending order of WL, NBI, and MB (P < 0.05). Among 51 MB-unstained lesions, 46 (90.2%) were proven to be duodenal neoplasms histologically. Duct openings were seen in 90.2% of tubular adenomas and tubulovillous adenomas. Finger-like projections were seen in 33.3% of tubular adenomas and in 88.2% of tubulovillous adenomas. Enlarged oval-shaped nuclei were observed in 100% of duodenal cancers, 33.3% of high-grade adenomas, and 9.4% of low-grade adenomas. MB staining allows more accurate detection of duodenal neoplasms in comparison to conventional WL and NBI observation. In cases of FAP, use of the maximum magnification power of the ECS may allow selection of lesions with high malignant potential.

[Does Colonic Stenting Affect the Long-Term Prognosis of Colorectal Cancer ?]

The impact of colonic stenting on long-term prognosis has not yet been clarified. We compared background factors, progression-free survival, and overall survival between patients with stents(stent group)who underwent surgery after colonic stenting as a bridge to surgery and patients without stents(non-stent group)who underwent emergency surgery for left-sided colorectal cancer ileus. There was no difference between the 2 groups in the induction of adjuvant chemotherapy, but the use of oxaliplatin-base was highly introduced in the stent group(p=0.03). The 5-year DFS rates were 55.1% and 70.3%(p=0.21)and the 5-year OS rates were 90.7%and 70%(p=0.35)in the stent and non-stent groups, respectively. In the present study, colon stent placement did not affect long-term prognosis.

Mesoporous Silica Nanoparticles with Dispersibility in Organic Solvents and Their Versatile Surface Modification.

Recently, colloidal mesoporous silica nanoparticles (MSNs) have attracted keen interest in scientific and technological fields. A significant issue regarding the effective use of colloidal MSNs is their dispersibility in various solvents, which is essential for their applications through surface modification. However, the dispersion media for colloidal MSNs have been extremely limited. Here, we report a new method for obtaining stable colloidal MSNs dispersed in various organic solvents through a gradual solvent exchange of colloidal MSNs from acidic water to an organic solvent by dialysis. This allows the colloidal MSNs to be dispersed as primary nanoparticles in organic solvents such as 1-butanol, 1-dodecanol, and tetrahydrofuran (THF), which are capable of hydrogen bonding with surface silanol groups. In addition, MSNs dispersed in THF can be modified with chlorosilanes while maintaining colloidal stability. Various organosilyl groups, such as trimethylsilyl and dimethylsilyl groups, can be densely grafted on the surfaces of MSNs. After trimethylsilylation, MSNs become dispersible even in a nonpolar and hydrophobic solvent like octane through the solvent exchange due to the preferential evaporation of THF. This method will offer a versatile approach to functionalizing colloidal MSNs toward a wide range of applications.

[A Case of Peritoneal Metastasis of Appendiceal Mucinous Carcinoma Successfully Managed by Multidisciplinary Treatment].

There is no established treatment for appendiceal mucinous adenocarcinoma. When this condition is complicated by pseudomyxoma peritonei(PMP), multidisciplinary treatment is often administered. A 40-year-old woman was diagnosed with right ovarian cancer for which laparotomy was performed. At the time of laparotomy, we considered the tumor to be an appendiceal carcinoma infiltrating the right ovary and performed ileocecal resection with lymph node dissection(D3)and right salpingo-oophorectomy. The pathological diagnosis was stage pT3, pN0, pM0, pStage Ⅱ mucinous adenocarcinoma of the appendix. Fourteen months later, the patient underwent abdominal total hysterectomy and left salpingo-oophorectomy because a CT scan suggested recurrence in the uterus, left fallopian tube, and ovary. Seventeen months after the second operation, despite adjuvant chemotherapy, CT revealed a peritoneal nodule in the pelvic cavity. Therefore, we administered chemotherapy comprising 5 lines for 32 months, which resulted in failure. CT showed an enlarged tumor and ascites and the patient became terminally ill. We repeatedly performed cytoreduction surgery and intraperitoneal chemotherapy, which improved her QOL. One year after discharge, abdominal CT showing an abdominal wall and intraperitoneal mass. We performed again cytoreduction surgery and intraperitoneal chemotherapy. Her postoperative course is good and she is currently an outpatient.

[A Case of Low-Grade Appendiceal Mucinous Neoplasm Complicated by Pseudomyxoma Peritoneri Successfully Treated with Cytoreductive Surgery and Intraperitoneal Chemotherapy].

We experienced a case of low-grade appendiceal mucinous neoplasm complicated by pseudomyxoma peritonei that was successfully treated with cytoreductive surgery and early postoperative intraperitoneal chemotherapy. The patient was a 26- year-old man with massive ascites and a swollen appendix on the computed tomography(CT). The appendix was a cystic mass of 5 cm in size. The entire parietal peritoneum, omentum, stomach, spleen, gall bladder, and entire colon were covered with numerous mucous nodules. Total colectomy, total gastrectomy, splenectomy, cholecystectomy, total omentectomy, parietal peritonectomy, ileostomy, and intraperitoneal irrigation were performed. The pathological diagnosis was low-grade appendiceal mucinous neoplasm. Postoperative intraperitoneal chemotherapy with cisplatin and mitomycin C was performed. A residual tumor was found on the dorsal side of the hepatoduodenal ligament 3 months postoperation on the CT. The residual tumor was successfully excised via a concomitant resection of the hepatic caudate lobe. Postoperative intraperitoneal chemotherapy was then performed. No recurrence was found at 8 months postoperation. The addition of early postoperative intraperitoneal chemotherapy improved the patient's quality of life in a short period. This could be one of the treatment options.

[Analysis of Palliative Stents for Colonic Stenosis Due to Extracolonic Cancers].

We retrospectively reviewed 13 patients in whom endoscopic stenting for colonic stenosis due to extracolonic cancers(non- CRC group)was attempted between July 2012 and January 2018. There were 5 men and 8 women, with a median age of 69 years. Primary malignancies causing colonic stenosis were gastric cancer(n=4), cholangiocarcinoma(n=2), pancreatic cancer(n=2), lung cancer(n=2), uterine cancer(n=2), and ovarian cancer(n=1). The non-CRC group patients demonstrated a significantly lower technical success rate than those who received palliative stents for colonic stenosis for primary colorectal cancer(n=51)(69% vs 98%, p<0.01). In addition, the non-CRC group patients(n=13)also demonstrated a significantly lower technical success rate(69% vs 99%, pp<0.01)than those who received stents aiming to subsequently undergo a bridge to surgery. Nonetheless, colorectal stenting for extracolonic malignancies appears to be a minimally invasive treatment and could offer patients rapid relief. Thus, it could be an effective alternative to some palliative therapies.