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Similarities in sizes, shapes, and physical properties between carbon dioxide (CO2) and acetylene (C2H2) make it a great challenge to separate the major impurity CO2 from products in C2H2 production. The use of porous materials is an appealing path to replace current very costly and energy‐consuming technologies, such as solvent extraction and cryogenic distillation; however, high CO2/C2H2 uptake ratio with minor adsorption of C2H2 at standard pressure was only unexpectedly observed in scarce examples in recent years although the related research started early at 1950s, and general design strategies to realize this aim are still absent. This work has successfully developed an efficient PIET strategy and obtained the second highest CO2/C2H2 adsorption ratio for porous materials in a proof‐of‐concept MOF with a photochromism‐active bipyridinium zwitterion. An unprecedented photocontrollable gate effect, owing to change of interannular dihedral after photoinduced generation of radical species, was also observed for the first time. These findings will inspire design and synthesis of porous materials for high efficient gas adsorption and separation. [ABSTRACT FROM AUTHOR]

The structural and electronic properties of two series of Group VB transition metal oxide clusters, MO and MO (M = Nb, Ta; n = 8-11), are investigated using density functional theory calculations. Generalized Koopmans' theorem is applied to predict the vertical detachment energies and simulate the photoelectron spectra. Large highest occupied molecular orbital-lowest unoccupied molecular orbital gaps are observed for these two stoichiometric MO clusters and estimated to be 3.98 and 4.38 eV for M = Nb and Ta, respectively. The MO (M = Nb, Ta) clusters are polyhedral cage structures with high symmetry ( T for the neutral and D for the anion) in which each metal atom joints three bridging and one terminal O atoms. For the Nb oxide species, NbO and NbO can be viewed as removing two and one terminal O atoms from NbO, respectively. The Ta species follow the same rule to the Nb species, except that the anionic TaO is formed by removing one terminal and one bridging O atoms from TaO. The TaO containing a localized Ta site can readily react with O to form the TaO which can also be viewed as replacing a terminal oxygen atom in TaO by a peroxo O unit, whereas the added oxygen atom is found to be a bridging one in the O-rich clusters NbO and the anionic TaO. Molecular orbital analyses are performed to analyze the chemical bonding in the tetra-nuclear metal oxide clusters and to elucidate their structural and electronic evolution. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculationsare employed to investigate the structural and electronic propertiesof bare tritungsten clusters (W3, W3–, W32–) and tritungsten oxide clustersW3Ox–/0(x= 1, 2). Generalized Koopmans’ theorem is appliedto predict the vertical detachment energies and simulate the photoelectronspectra (PES) for W3Ox–(x= 0–2) clusters. ExtensiveDFT calculations are performed in search of the lowest energy structuresfor both the anions and the neutrals. The bare tritungsten clustersare predicted to be triangular structures with D3h(3A1′), C2v(2A1) and D3h(1A1′) symmetry for W3, W3–and W32–, respectively.For W3O–and W3O clusters,the oxygen atom occupies the terminal site, while the next added oxygenatom is found to be a bridging one in both W3O2–and W3O2clusters. Molecularorbital analyses are carried out to elucidate the chemical bondingof these clusters and provide insights into the sequential oxidationfrom W3–to W3O2–. Partial σ- and δ-aromaticity arerevealed in the neutral W3(D3h, 3A1′), while the anionW32–(D3h, 1A1′) possesses onlyδ-aromaticity. [ABSTRACT FROM AUTHOR]

Chalcohalides not only keep the balance between the nonlinear optical (NLO) coefficient and wide band gap, but also provide a promising solution to achieve sufficient birefringence for phase-matching ability in NLO crystals. In this study, a novel chalcohalide, Cs 4 Zn 5 P 6 S 18 I 2 (1) is successfully synthesized, by incorporating the highly electropositive Cs and the large electronegative I element into the zinc thiophosphate. Its 3D open framework features an edge-shared by distorted [ZnS 4 ], ethanol-like [P 2 S 6 ], and unusual [ZnS 2 I 2 ] polyhedrons, which is inconsistent with the soft-hard-acids-bases theory. Remarkably, compound 1 simultaneously exhibits the large second-harmonic generation (SHG, 1.1×AgGaS 2 , @1.3 µm) and a wide band gap (3.75 eV) toward a high laser-induced damage threshold (16.7×AgGaS 2 , @1.06 µm), satisfying the rigorous requirements for a prominent infrared NLO material with concurrent SHG intensity (≥0.5×AGS) and band gap (≥3.5 eV). Moreover, to the best of the knowledge, the experimental result shows that phase 1 has the largest birefringence (0.108, @546 nm) in chalcohalide and meets phase-matching behavior demand originating from the polarizable anisotropy of NLO-functional motifs. This finding may provide great opportunities for designing birefringent chalcohalides., (© 2023 Wiley-VCH GmbH.)

Similarities in sizes, shapes, and physical properties between carbon dioxide (CO 2 ) and acetylene (C 2 H 2 ) make it a great challenge to separate the major impurity CO 2 from products in C 2 H 2 production. The use of porous materials is an appealing path to replace current very costly and energy-consuming technologies, such as solvent extraction and cryogenic distillation; however, high CO 2 /C 2 H 2 uptake ratio with minor adsorption of C 2 H 2 at standard pressure was only unexpectedly observed in scarce examples in recent years although the related research started early at 1950s, and general design strategies to realize this aim are still absent. This work has successfully developed an efficient PIET strategy and obtained the second highest CO 2 /C 2 H 2 adsorption ratio for porous materials in a proof-of-concept MOF with a photochromism-active bipyridinium zwitterion. An unprecedented photocontrollable gate effect, owing to change of interannular dihedral after photoinduced generation of radical species, was also observed for the first time. These findings will inspire design and synthesis of porous materials for high efficient gas adsorption and separation., (© 2021 Wiley-VCH GmbH.)

Exploring nonlinear optical (NLO) functional motifs (FM, the structural origin of NLO efficiency) is vital for the rational design of NLO materials. Normal spectrum techniques applied in studying photon exciting materials are invalid for NLO materials, in which electrons are not excited substantially but only distorted under laser. A general strategy of determining NLO FM is proposed by comparative studies of experimental electron density (ED) without and under the laser. The in situ experimental ED and wavefunction of typical NLO material LiB 3 O 5 (LBO) under dark and 360 and 1064 nm lasers are investigated. Compared with the initial state under dark, the ED of [B 3 O 5 ] - unit at functional states under laser irradiation exhibits remarkable changes of topological atomic and bond properties, confirming the NLO FM being [B 3 O 5 ] - . The work extracts for the first time the FM of a NLO material experimentally and highlights the crucial role of in situ ED analysis in studying NLO mechanisms., (© 2021 Wiley-VCH GmbH.)

Aim: To evaluate the efficacy, safety and feasibility of endoscopic full-thickness resection (EFR) for the treatment of gastric submucosal tumors (SMTs) arising from the muscularis propria., Methods: A total of 35 gastric SMTs arising from the muscularis propria layer were resected by EFR between January 2010 and September 2013. EFR consists of five major steps: injecting normal saline into the submucosa; pre-cutting the mucosal and submucosal layers around the lesion; making a circumferential incision as deep as the muscularis propria around the lesion using endoscopic submucosal dissection and an incision into the serosal layer around the lesion with a Hook knife; a full-thickness resection of the tumor, including the serosal layer with a Hook or IT knife; and closing the gastric wall with metallic clips., Results: Of the 35 gastric SMTs, 14 were located at the fundus, and 21 at the corpus. EFR removed all of the SMTs successfully, and the complete resection rate was 100%. The mean operation time was 90 min (60-155 min), the mean hospitalization time was 6.0 d (4-10 d), and the mean tumor size was 2.8 cm (2.0-4.5 cm). Pathological examination confirmed the presence of gastric stromal tumors in 25 patients, leiomyomas in 7 and gastric autonomous nerve tumors in 2. No gastric bleeding, peritonitis or abdominal abscess occurred after EFR. Postoperative contrast roentgenography on the third day detected no contrast extravasation into the abdominal cavity. The mean follow-up period was 6 mo, with no lesion residue or recurrence noted., Conclusion: EFR is efficacious, safe and minimally invasive for patients with gastric SMTs arising from the muscularis propria layer. This technique is able to resect deep gastric lesions while providing precise pathological information about the lesion. With the development of EFR, the indications of endoscopic resection might be extended.

The small intestine is approximately 5-6 m long and occupies a large area in the abdominal cavity. These factors preclude the use of ordinary endoscopy and X-ray to thoroughly examine the small intestine for bleeding of vascular malformations. Thus, the diagnosis of intestinal bleeding is very difficult. A 47-year-old man presented at the hospital 5 mo ago with dark stool. Several angiomas were detected by oral approach enteroscopy, but no active bleeding was observed. Additionally, no lesions were detected by anal approach enteroscopy; however, gastrointestinal tract bleeding still occurred for an unknown reason. We performed an abdominal vascular enhanced computed tomography examination and detected ileal vascular malformations. Ileum angioma and vascular malformation were detected by a laparoscopic approach, and segmental resection was performed for both lesions, which were confirmed by pathological diagnosis. This report systemically emphasizes the imaging findings of small intestinal vascular malformation bleeding.

Aim: To assess the effectiveness of endoscopic full-thickness resection (EFR) and laparoscopic surgery in the treatment of gastric stromal tumors arising from the muscularis propria., Methods: Out of 62 gastric stromal tumors arising from the muscularis propria, each > 1.5 cm in diameter, 32 were removed by EFR, and 30 were removed by laparoscopic surgery. The tumor expression of CD34, CD117, Dog-1, S-100, and SMA was assessed immunohistochemically. The operative time, complete resection rate, length of hospital stay, incidence of complications, and recurrence rate were compared between the two groups. Continuous data were compared using independent samples t-tests, and categorical data were compared using χ (2) tests., Results: The 32 gastric stromal tumors treated by EFR and the 30 treated by laparoscopic surgery showed similar operative time [20-155 min (mean, 78.5 ± 30.1 min) vs 50-120 min (mean, 80.9 ± 46.7 min), P > 0.05], complete resection rate (100% vs 93.3%, P > 0.05), and length of hospital stay [4-10 d (mean, 5.9 ± 1.4 d) vs 4-19 d (mean, 8.9 ± 3.2 d), P >0.05]. None of the patients treated by EFR experienced complications, whereas two patients treated by laparoscopy required a conversion to laparotomy, and one patient had postoperative gastroparesis. No recurrences were observed in either group. Immunohistochemical staining showed that of the 62 gastric stromal tumors diagnosed by gastroscopy and endoscopic ultrasound, six were leiomyomas (SMA-positive), one was a schwannoglioma (S-100 positive), and the remaining 55 were stromal tumors., Conclusion: Some gastric stromal tumors arising from the muscularis propria can be completely removed by EFR. EFR could likely replace surgical or laparoscopic procedures for the removal of gastric stromal tumors.

The electronic and structural properties of monohafnium oxide clusters, HfO(n)(-) and HfO(n) (n = 1-6), are investigated using anion photoelectron spectroscopy and density-functional theory at the B3LYP level. The observed ground-state adiabatic detachment energy is low for HfO(-) (0.5 ± 0.1 eV) and HfO(2)(-) (2.125 ± 0.010 eV), roughly constant for HfO(3)(-) (3.6 ± 0.1 eV), HfO(4)(-) (3.67 ± 0.05 eV), and HfO(5)(-) (3.9 ± 0.1 eV), and substantially higher for HfO(6)(-) (4.9 ± 0.1 eV). Activated oxygen species, such as radical, superoxide, peroxide, diradical, and triradical, are identified in the HfO(n)(-) and HfO(n) clusters. The Hf center is shown to be flexible to accommodate the oxygen species. The sum of formal Hf-O bond orders around the Hf center is equal to four for all of the neutral clusters studied, and five for all of the anions. The O-rich HfO(n)(-) and HfO(n) (n = 3-6) clusters provide well-defined molecular models to understand O(2) adsorption and activation on an Hf center.