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1.
Front Plant Sci ; 15: 1396553, 2024.
Article in English | MEDLINE | ID: mdl-38711610

ABSTRACT

Some species of the genus Aegilops, a wild relative of wheat, carry chromosomes that after introducing to wheat exhibit preferential transmission to progeny. Their selective retention is a result of the abortion of gametes lacking them due to induced chromosomal aberrations. These chromosomes are termed Gametocidal (Gc) and, based on their effects, they are categorized into three types: mild, intense or severe, and very strong. Gc elements within the same homoeologous chromosome groups of Aegilops (II, III, or IV) demonstrate similar Gc action. This review explores the intriguing dynamics of Gc chromosomes and encompasses comprehensive insights into their source species, behavioral aspects, mode of action, interactions, suppressions, and practical applications of the Gc system in wheat breeding. By delving into these areas, this work aims to contribute to the development of novel plant genetic resources for wheat breeding. The insights provided herein shed light on the utilization of Gc chromosomes to produce chromosomal rearrangements in wheat and its wild relatives, thereby facilitating the generation of chromosome deletions, translocations, and telosomic lines. The Gc approach has significantly advanced various aspects of wheat genetics, including the introgression of novel genes and alleles, molecular markers and gene mapping, and the exploration of homoeologous relationships within Triticeae species. The mystery lies in why gametes possessing Gc genes maintain their normality while those lacking Gc genes suffer abnormalities, highlighting an unresolved research gap necessitating deeper investigation.

2.
J Vasc Surg Cases Innov Tech ; 10(2): 101368, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38566912

ABSTRACT

We describe a case of endovascular treatment for an iatrogenic left vertebral artery injury after central line catheter placement in a 68-year-old male patient. The patient had a massive pulmonary embolism, and a Swan-Ganz catheter was required to monitor the patient's circulatory condition. However, the catheter was inserted into the left vertebral artery and passed through the left internal jugular vein. Endovascular treatment was indicated due to the patient's poor general health. Complete hemostasis was achieved, and the postoperative course was uneventful without neurologic deficits.

3.
J Surg Case Rep ; 2024(3): rjae180, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38524678

ABSTRACT

Eliminating necrotic and infected tissues is crucial for limb salvage in patients with chronic limb-threatening ischemia (CLTI). However, extensive lesions that involve the midfoot frequently result in transtibial amputation, restricting ambulation and independent life. The Modified Pirogoff amputation, which includes a 90° rotation of the calcaneus and fixation with the tibia, has good functional outcomes in trauma cases. Here, we report two patients with CLTI successfully managed by a combination of revascularization and modified Pirogoff amputation, resulting in preserved ambulation without a prosthesis. Modified Pirogoff amputation may be a good alternative in revascularized CLTI with extensive tissue loss of the midfoot.

4.
Ann Vasc Surg ; 102: 42-46, 2024 May.
Article in English | MEDLINE | ID: mdl-38307233

ABSTRACT

BACKGROUND: The Global Limb Anatomic Staging System (GLASS) has been widely used to evaluate patients with chronic limb-threatening ischemia (CLTI). As end-stage kidney disease (ESKD) is a well-known CLTI risk factor, we aimed to determine whether patients on hemodialysis (HD) have a worse limb prognosis than those without ESKD, considering the same GLASS background. METHODS: The data of 445 patients who underwent surgical and/or endovascular revascularization procedures for lower extremity ischemia were retrospectively collected in our division between 2005 and 2018. The major amputation rate and amputation-free survival (AFS) were compared between HD and non-HD patients. RESULTS: Among the 215 (48%) patients receiving HD, 58 limbs required major amputation (27% limb loss rate). Among the non-HD group, the limb loss rate was 13% (P < 0.0001). The overall AFS was significantly worse in patients receiving HD than those not (P < 0.0001). The AFS was significantly worse in HD patients when comparing GLASS-standardized subgroups. CONCLUSIONS: Patients with CLTI who were receiving HD had a worse limb prognosis than those not receiving, even when considering the same GLASS classification. Furthermore, there is a need for an ideal guideline focused on ESKD-directed peripheral artery disease.


Subject(s)
Endovascular Procedures , Kidney Failure, Chronic , Peripheral Arterial Disease , Humans , Chronic Limb-Threatening Ischemia , Retrospective Studies , Treatment Outcome , Limb Salvage/methods , Peripheral Arterial Disease/diagnostic imaging , Peripheral Arterial Disease/therapy , Risk Factors , Kidney Failure, Chronic/diagnosis , Kidney Failure, Chronic/therapy , Renal Dialysis/adverse effects , Lower Extremity/blood supply , Ischemia/diagnostic imaging , Ischemia/surgery , Chronic Disease
5.
In Vivo ; 37(6): 2803-2807, 2023.
Article in English | MEDLINE | ID: mdl-37905664

ABSTRACT

BACKGROUND/AIM: Incisional hernia is among the most prevalent complications associated with open abdominal aortic aneurysm repair. However, risk factors for incisional hernias in patients with abdominal aortic aneurysm are multifactorial. Therefore, this study evaluated the risk factors of incisional hernia after open abdominal aortic aneurysm repair, including surgical factors. PATIENTS AND METHODS: We retrospectively extracted data from patients with incisional hernias after abdominal aortic aneurysm repair between 2012 and 2019 and investigated their perioperative characteristics and wound closure techniques. RESULTS: The mean follow-up periods were 41.5±30.3 months, and 30 of 131 (22.9%) patients suffered an incisional hernia. Regarding the underlying disease, only diabetes mellitus was significantly more common in the incisional hernia group (11 of 30 patients, 36.6%), and no significant differences were found in the patients' perioperative data. Interrupted sutures were used in all 30 patients in the hernia group. Moreover, in 8 of the 101 remaining cases, barbed sutures were used, and no incisional hernia occurred in any of these cases. CONCLUSION: In addition to diabetes mellitus, abdominal aortic aneurysm is a significant risk factor for incisional hernia after abdominal aortic aneurysm repair. Therefore, employing the barbed suture technique may effectively prevent incisional hernias after abdominal aortic aneurysm repair.


Subject(s)
Aortic Aneurysm, Abdominal , Diabetes Mellitus , Hernia, Ventral , Incisional Hernia , Humans , Incisional Hernia/epidemiology , Incisional Hernia/etiology , Hernia, Ventral/etiology , Hernia, Ventral/prevention & control , Hernia, Ventral/surgery , Retrospective Studies , Aortic Aneurysm, Abdominal/surgery , Aortic Aneurysm, Abdominal/complications , Risk Factors , Surgical Mesh/adverse effects
6.
Surg Case Rep ; 9(1): 97, 2023 Jun 07.
Article in English | MEDLINE | ID: mdl-37280481

ABSTRACT

BACKGROUND: Postoperative cholangitis is a complication of biliary reconstruction during hepatobiliary pancreatic surgery. Most cases are associated with anastomotic stenosis, but there are also cases of cholangitis without stenosis, and treatment can be difficult, especially in patients with recurrent symptoms. In this report, we describe a case of repeated nonobstructive cholangitis in a patient after total pancreatectomy, in which a good outcome was obtained after performing tract conversion surgery. CASE PRESENTATION: The patient was a 75-year-old man. He underwent total pancreatectomy for stage IIA cancer of the pancreatic body, hepaticojejunostomy via the posterior colonic route, gastrojejunostomy and Braun anastomosis via the anterior colonic route using the Billroth II method. The patient had a good postoperative course and was receiving adjuvant chemotherapy on an outpatient basis, but he developed his first episode of cholangitis 4 months after surgery. Although conservative treatment with antimicrobial agents was successful, the patient continued to have recurrent biliary cholangitis and was repeatedly admitted and discharged from the hospital. Since stenosis at the anastomosis was suspected, endoscopic observation of the anastomosis was performed using small bowel endoscopy for close examination, but no apparent stenosis was observed. Small bowel imaging indicated a possible influx of contrast medium into the bile duct, and reflux due to food residue was suspected as the cause of cholangitis. Since conservative treatment alone did not suppress the flare-up of symptoms, the decision was made to perform tract conversion surgery for curative purposes. The afferent loop was cut midstream, and jejunojejunostomy was performed downstream. The postoperative course was good, and the patient was discharged on the 10th day after surgery. He is currently an outpatient and has been free of cholangitis symptoms for 4 years without cancer recurrence. CONCLUSIONS: Although the diagnosis of nonobstructive retrograde cholangitis can be difficult, surgical treatment should be considered in patients with recurrent symptoms and refractory treatment.

7.
ACS Appl Mater Interfaces ; 15(19): 23512-23517, 2023 May 17.
Article in English | MEDLINE | ID: mdl-37134115

ABSTRACT

Thermal transistors have potential as thermal management devices because they can electrically control the thermal conductivity (κ) of the active layer. Recently, we realized solid-state electrochemical thermal transistors by utilizing the electrochemical redox reaction of SrCoOy (2 ≤ y ≤ 3). However, the guiding principle to improve the on/off κ ratio has yet to be clarified because the κ modulation mechanism is unclear. This study systematically modulates κ of SrCo1-xFexOy (0 ≤ x ≤ 1, 2 ≤ y ≤ 3) solid solutions used as the active layers in solid-state electrochemical thermal transistors. When y = 3, the lattice κ of SrCo1-xFexOy is ∼2.8 W m-1 K-1 and insensitive to x. When x = 0 and y = 3, κ increases to ∼3.8 W m-1 K-1 due to the contribution of the electron κ. When y = 2, κ slightly depends on the ordered atomic arrangement. Materials that are high electrical conductors with highly ordered lattices when the transistor is on but are electrical insulators with disordered lattices when the transistor is off should be well-suited for the active layers of solid-state electrochemical thermal transistors.

8.
Foods ; 12(5)2023 Feb 23.
Article in English | MEDLINE | ID: mdl-36900471

ABSTRACT

Immunoglobulin E (IgE)-mediated food allergies to wheat that develop after school age typically shows a type of wheat-dependent exercise-induced anaphylaxis (WDEIA). At present, avoidance of wheat products or postprandial rest after ingesting wheat is recommended for patients with WDEIA, depending on the severity of the allergy symptoms. ω5-Gliadin has been identified as the major allergen in WDEIA. In addition, α/ß-, γ-, and ω1,2-gliadins, high and low molecular weight-glutenins, and a few water-soluble wheat proteins have been identified as IgE-binding allergens in a small proportion of patients with IgE-mediated wheat allergies. A variety of approaches have been manufactured to develop hypoallergenic wheat products that can be consumed by patients with IgE-mediated wheat allergies. In order to analyze such approaches, and to contribute to the further improvement, this study outlined the current status of these hypoallergenic wheat productions, including wheat lines with a reduced allergenicity that are mostly constructed for the patients sensitized to ω5-gliadin, hypoallergenic wheat by enzymic degradation/ion exchanger deamidation, and hypoallergenic wheat by thioredoxin treatment. The wheat products obtained by these approaches significantly reduced the reactivity of Serum IgE in wheat-allergic patients. However, either these were not effective on some populations of the patients, or low-level IgE-reactivity to some allergens of the products was observed in the patients. These results highlight some of the difficulties faced in creating hypoallergenic wheat products or hypoallergenic wheat lines through either traditional breeding or biotechnology approaches in developing hypoallergenic wheat completely safe for all the patients allergic to wheat.

9.
J Vasc Surg Cases Innov Tech ; 9(2): 101129, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36970138

ABSTRACT

We have described a case of multiple surgeries for a ruptured popliteal artery in an 11-year-old female patient with vascular Ehlers-Danlos syndrome. She underwent emergency hematoma evacuation and ruptured popliteal artery interposition with the great saphenous vein graft, which was notably fragile during surgery and had ruptured on the seventh postoperative day. We performed another emergency hematoma evacuation and popliteal artery interposition with an expanded polytetrafluoroethylene vascular graft. Despite the early occlusion of the expanded polytetrafluoroethylene graft, she recovered with mild intermittent claudication in the left lower extremity and was discharged on postoperative day 20 after the first surgery.

10.
Gan To Kagaku Ryoho ; 49(5): 597-599, 2022 May.
Article in Japanese | MEDLINE | ID: mdl-35578943

ABSTRACT

A 52-year-old man diagnosed with Stage ⅢA rectal and anal canal cancer underwent abdominal perineal resection using Miles's method. Two years later, local recurrence and lung metastases were detected using contrasted CT imaging. First-line chemotherapy of XELOX was administered for 4 months until the disease progressed and lung metastases developed. After 4 courses of second-line IRIS plus bevacizumab chemotherapy, fever and swelling of the right buttock appeared; he visited and was admitted to our hospital. A CT scan revealed a pelvic abscess which resulted in septic shock. Swelling and pain extended to the right scrotum, and acute necrotizing fasciitis was suspected, and emergency surgery was performed. An incision was made from the right buttock to the right scrotum, bloody purulent drainage with a foul odor was observed, and a diagnosis of Fournier's gangrene was made. Although typical CT findings such as emphysema due to gas-producing bacteria were not observed in this case, early diagnosis and intervention of systemic management including early surgical drainage and operation were effective. For pelvic infections occurring during bevacizumab chemotherapy, Fournier's gangrene should considered for differential diagnosis, even if CT findings are atypical.


Subject(s)
Anus Neoplasms , Fournier Gangrene , Lung Neoplasms , Anal Canal/pathology , Bevacizumab , Fournier Gangrene/surgery , Humans , Male , Middle Aged
11.
Clin J Gastroenterol ; 15(1): 185-191, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34767241

ABSTRACT

A 70-year-old Japanese woman who was treated for interstitial pneumonia (IP) with steroid therapy developed cholecystitis. A serial computed-tomography (CT) imaging showed irregular thickness of the fundus wall of the gallbladder and two rapidly enlarged lymph nodes (LNs): number (no.) 12 and no. 8a. Positron-emission tomography-computed tomography (PET-CT) scan showed an abnormal uptake at the site of the gallbladder tumor and those LNs. We subsequently performed open radical cholecystectomy and LN dissection of the no. 12 and 8a LNs, following complete remission of IP. The histology showed gallbladder adenocarcinoma, with a single focus of neuroendocrine carcinoma (NEC) component of less than 30%; Ki-67 index > 80%, synaptophysin (Syn) (+), chromogranin A (CgA) (+), and clusters of differentiation (CD) 56 (+) (T2bN1M0, Stage IIIB). LN no. 8a was diffusely metastatic with NEC components. LN no. 12c, which was adjacent to the cystic duct, revealed necrosis without apparent tumor cells, but was highly suspicious for tumor necrosis. The final diagnosis was adenocarcinoma of the gallbladder with focal NEC (< 30%), which did not meet the criteria for mixed neuroendocrine-non-neuroendocrine neoplasm (MiNEN). Postoperatively, she completed 4 cycles of adjuvant chemotherapy for NEC (Cisplatin plus Etoposide), and no recurrence was observed after 12 months.


Subject(s)
Adenocarcinoma , Carcinoma, Neuroendocrine , Gallbladder Neoplasms , Adenocarcinoma/diagnostic imaging , Adenocarcinoma/drug therapy , Adenocarcinoma/surgery , Aged , Carcinoma, Neuroendocrine/diagnostic imaging , Carcinoma, Neuroendocrine/drug therapy , Carcinoma, Neuroendocrine/surgery , Female , Gallbladder , Gallbladder Neoplasms/diagnostic imaging , Gallbladder Neoplasms/drug therapy , Gallbladder Neoplasms/surgery , Humans , Lymphatic Metastasis , Positron Emission Tomography Computed Tomography
12.
J Anus Rectum Colon ; 5(3): 274-280, 2021.
Article in English | MEDLINE | ID: mdl-34395940

ABSTRACT

OBJECTIVES: Surgery for colonic perforation has high morbidity and mortality rates. Predicting complications preoperatively would help improve short-term outcomes; however, no predictive risk stratification model exists to date. Therefore, the current study aimed to determine risk factors for complications after colonic perforation surgery and use machine learning to construct a predictive model. METHODS: This retrospective study included 51 patients who underwent emergency surgery for colorectal perforation. We investigated the connection between overall complications and several preoperative indicators, such as lactate and the Glasgow Prognostic Score. Moreover, we used the classification and regression tree (CART), a machine-learning method, to establish an optimal prediction model for complications. RESULTS: Overall complications occurred in 32 patients (62.7%). Multivariate logistic regression analysis identified high lactate levels [odds ratio (OR), 1.86; 95% confidence interval (CI), 1.07-3.22; p = 0.027] and hypoalbuminemia (OR, 2.56; 95% CI, 1.06-6.25; p = 0.036) as predictors of overall complications. According to the CART analysis, the albumin level was the most important parameter, followed by the lactate level. This prediction model had an area under the curve (AUC) of 0.830. CONCLUSIONS: Our results determined that both preoperative albumin and lactate levels were valuable predictors of postoperative complications among patients who underwent colonic perforation surgery. The CART analysis determined optimal cutoff levels with high AUC values to predict complications, making both indicators clinically easier to use for decision making.

13.
Biomolecules ; 11(8)2021 07 27.
Article in English | MEDLINE | ID: mdl-34439772

ABSTRACT

A prosthetic vascular graft that induces perigraft tissue incorporation may effectively prevent serious sequelae such as seroma formation and infection. Radiation-crosslinked gelatin hydrogel (RXgel) mimics the chemical and physical properties of the in vivo extracellular matrix and may facilitate wound healing by promoting tissue organization. Fibroblasts cultured on RXgel actively migrated into the gel for up to 7 days. RXgels of three different degrees of hardness (Rx[10], soft; Rx[15], middle; Rx[20], hard) were prepared, and small disc-like samples of RXgels were implanted into rats. In vitro and in vivo results indicated that Rx[10] was too soft to coat vascular grafts. Thus, expanded polytetrafluoroethylene (ePTFE) vascular grafts coated with RXgel were developed using Rx[15] and Rx[20] gels, and ring-shaped slices of the graft were implanted into rats. Alpha-smooth muscle actin (αSMA) and type III collagen (Col-III) levels were detected by immunohistochemistry. Immunohistochemical staining for αSMA and Col-III demonstrated that RXgel-coated vascular grafts induced more granulation tissue than non-coated grafts on days 14 and 28 after implantation. RXgel-coated ePTFE vascular grafts may provide a solution for patients by reducing poor perigraft tissue incorporation.


Subject(s)
Blood Vessel Prosthesis , Fibroblasts/metabolism , Gelatin/chemistry , Hydrogels/chemistry , Polytetrafluoroethylene/chemistry , Vascular Grafting/instrumentation , 3T3 Cells , Actins/metabolism , Animals , Cell Movement , Coated Materials, Biocompatible , Cross-Linking Reagents/chemistry , Hyperplasia , Immunohistochemistry , Male , Mice , Rats , Rats, Sprague-Dawley , Seroma/pathology
14.
Carbohydr Polym ; 255: 117365, 2021 Mar 01.
Article in English | MEDLINE | ID: mdl-33436198

ABSTRACT

Quinacridone, a red pigment, is prone to aggregation, which results in undesirable color changes. Cellulose nanofibers (NFs) have been reported to adsorb quinacridone and suppress its aggregation. In this study, we investigated the potential of chitin and chitosan NFs which possess acetoamide and amino groups, as a quinacridone dispersant. Chitosan NFs, obtained by fibrillation using high-pressure homogenizer, adsorbed more quinacridone than cellulose NFs. SEM observations showed that chitosan NFs inhibited the aggregation of quinacridone, but chitin NFs did not. NMR analysis suggested the hydrogen bonding between chitosan NFs and quinacridone induced by the amino groups. The results indicated that the amino groups more facilitated the intermolecular interactions between NFs and quinacridone than the hydroxyl groups whereas the acetamide groups hindered them. Color measurements showed that the redness of quinacridone improved when cellulose or chitosan NFs were added. Chitosan NFs were found to be a novel candidate for quinacridone dispersants.

15.
RSC Adv ; 11(20): 12330-12335, 2021 Mar 23.
Article in English | MEDLINE | ID: mdl-35423780

ABSTRACT

Silica is not only a biocompatible trace element but also an essential element for bone formation and metabolism. Therefore, it is often doped into bioceramics such as calcium phosphate and calcium carbonate for enhancing biomaterial ability. Heretofore, organic silica materials are employed as silica sources, but the residual organic matter is a significant drawback in biomaterial applications. Therefore, in this study, we introduce a one-pot inorganic synthesis method for the formation of silica-doped octacalcium phosphate (OCP) using Na2SiO3 as the silica source. Silica was intercalated into the OCP unit lattice, replacing its hydrous layer structure, and then a layer-by-layer structure of apatite and silica was formed. Furthermore, by immersing the fabricated silica-doped OCP into suitable solutions, both silica-doped hydroxyapatite and carbonate apatite were fabricated through a one-step inorganic processes.

16.
Int J Surg Case Rep ; 76: 202-206, 2020.
Article in English | MEDLINE | ID: mdl-33039783

ABSTRACT

INTRODUCTION: Peripheral artery pseudoaneurysm as a consequence of arterial deterioration is relatively rare in young populations, who typically lack an atherosclerotic background. Such pseudoaneurysms are known to pose a risk of rupture, which is correlated with high mortality and morbidity rates. Pseudoaneurysms are more prone to rupture than true aneurysms are, as their vessel walls tear more easily. We present the case of a 50-year-old patient who had multiple arterial deteriorations. CASE PRESENTATION: The patient experienced backache, and computed tomography revealed a tear of the right renal artery, and a pseudoaneurysm of the left internal iliac artery. He had a history of graft replacement for the right superficial artery pseudoaneurysm, which had been occluded. Although various tests were performed for differential diagnosis, the etiology was unidentified. Considering the suspected vascular fragility and failure of previous direct intervention, these 2 lesions were treated by placing endografts simultaneously. DISCUSSION: We investigated various diseases causing vascular fragility in the reported case, such as vascular Behçet disease, vascular Ehlers-Danlos syndrome, fibromuscular dysplasia, and segmental arterial mediolysis. However, these were all excluded and the etiology remains unclear. Progress in endovascular techniques enables the use of minimally invasive treatment in patients with vascular fragility. CONCLUSION: When vascular fragility may exist, endovascular treatment is a desirable option, as it can be performed repetitively and is less invasive.

17.
Genes Genet Syst ; 95(2): 95-99, 2020 Jul 08.
Article in English | MEDLINE | ID: mdl-32173682

ABSTRACT

Most deletions for the short arm of chromosome 2A (2AS), and the telocentric chromosome for the long arm of chromosome 2A (2AL), are available only in the heterozygous condition in 'Chinese Spring' hexaploid wheat. This is due to the female sterility, and therefore self-sterility, of their homozygotes, caused by the partial or entire loss of the 2AS chromosome arm on which genes for normal synapsis and female fertility are located. On the other hand, a D-genome disomic substitution line 2D(2A) of 'Langdon' tetraploid wheat, in which chromosome 2D is disomically substituted for chromosome 2A, is available (i.e., self-fertile) despite chromosome 2A being missing in this line. This fact indicates that another gene for female fertility must be present in Langdon 2D(2A). We attempted to develop self-fertile 2AS homozygous deletion and ditelosomic 2AL lines by transferring this female fertility gene, through a series of crosses and cytological screening, from Langdon 2D(2A) to the two aneuploid lines. We finally obtained self-fertile 2AS homozygous deletion and ditelosomic 2AL lines. These lines displayed normal meiotic chromosome pairing and lacked all 12 of the 2AS markers used for PCR analysis.


Subject(s)
Chromosomes, Plant/genetics , Plant Breeding/methods , Plant Infertility/genetics , Triticum/genetics , Aneuploidy , Chromosome Deletion , Chromosome Pairing , Homozygote , Tetraploidy , Triticum/physiology
19.
Inorg Chem ; 58(24): 16752-16760, 2019 Dec 16.
Article in English | MEDLINE | ID: mdl-31774662

ABSTRACT

Perovskite-type oxynitride BaTaO2N has been attracting attention for its large dielectric constant, which is almost independent of the temperature by measurements on its ceramics. Its dielectric characteristics are attributed to polar nanoregions (PNRs) in the average cubic crystal structure. Polarization saturation to produce a butterfly-like piezoresponse force microscopy (PFM) signal was observed on BaTaO2N crystals in the present study. Reddish crystallites of BaTaO2N of up to 3.1 µm in size were grown using a BaCN2 flux. Grain growth proceeded through the formation of a Ruddlesden-Popper-type oxynitride from the reaction between BaTaO2N powder and molten BaCN2. Their electrical property was studied using PFM with special care because of the small size of the crystals. They were found to be much more highly insulating than its ceramics. Ferroelectricity with complete phase inversion was observed on an oxynitride perovskite crystal for the first time. A large coercivity of 50-60 V was observed in the measurement. Such ferroelectricity is ascribed to the PNRs induced by the polar linkages between cis-type TaO4N2 octahedra.

20.
ACS Omega ; 4(8): 12995-13004, 2019 Aug 20.
Article in English | MEDLINE | ID: mdl-31460426

ABSTRACT

Silicalite-1-type zeolites with unique intracrystal holes or cracks were successfully prepared using a cellulose nanofiber (CNF) as an additional mediating material, and their vapor phase adsorption properties toward methyl tert-butyl ether (MTBE) and n-nitrosodimethylamine (NDMA) were examined. It was found that the mixing protocol of CNF and structure-directing agents (SDAs), the addition amount of CNF, and the CNF/SDAs amount ratio play important roles in forming the holed silicalite-1. The synthesis route that preliminarily mixes CNF with SDAs in a series of controlled conditions is particularly beneficial for the formation of the holed silicalite-1 with mesoporosity and larger pores because the CNF-SDAs composite structure benefits the zeolite growth closely encompassing CNF inside the crystal structure. It also promotes the preferential formation of the orthorhombic phase vicinal to the CNF surface, namely, the surface of the formed internal holes or cracks, with the twin-type crystal size reduced as compared to the non-CNF-templated sample. On the contrary, the synthesis route that mixes CNF with SDAs-silicate composite ions tends to modify the twin-type crystal shape at the same time to form small but uniform well-crystallized particles with less holes or cracks and a dominative monoclinic phase. It was considered that both the inter-subunit structural defect and silanol defect whose content is increased with CNF addition influence the adsorptivity of MTBE and NDMA. Owing to the small twin-type crystal size, the smaller crystal subunits, and the favored short path from the surface of internal holes or cracks, the holed silicalite-1 derived from the CNF and SDA premixture assures the easiest access of adsorbate molecules to the most energetically favored sites and is most appropriate for the adsorption of both MTBE and NDMA among the examined zeolites.

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