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1.
Sci Technol Adv Mater ; 25(1): 2378684, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39135761

RESUMO

The cubic perovskite SrMoO3 with a paramagnetic ground state and remarkably low room-temperature resistivity has been considered as a suitable candidate for the new-era oxide-based technology. However, the difficulty of preparing single-phase SrMoO3 thin films by hydrogen-free sputtering has hindered their practical use, especially due to the formation of thermodynamically favorable SrMoO4 impurity. In this work, we developed a radio frequency sputtering technology enabling the reduction reaction and achieved conductive epitaxial SrMoO3 films with pure phase from a SrMoO4 target in a hydrogen-free, pure argon environment. We demonstrated the significance of controlling the target-to-substrate distance (TSD) on the synthesis of SrMoO3; the film resistivity drastically changes from 1.46 × 105 µΩ·cm to 250 µΩ·cm by adjusting the TSD. Cross-sectional microstructural analyses demonstrated that films with the lowest resistivity, deposited for TSD = 2.5 cm, possess a single-phase SrMoO3 with an epitaxial perovskite structure. The formation mechanism of the conductive single-phase SrMoO3 films can be attributed to the plasma-assisted growth process by tuning the TSD. Temperature-dependent resistivity and Hall effect studies revealed metal-like conducting properties for low-resistive SrMoO3 films, while the high-resistive ones displayed semiconductor-like behavior. Our approach makes hydrogen-free, reliable and cost-efficient scalable deposition of SrMoO3 films possible, which may open up promising prospects for a wide range of future applications of oxide materials.


For the first time, we developed a plasma-assisted RF sputtering technology enabling the reduction reaction for the synthesis of single-phase conductive SrMoO3 epitaxial films from insulating SrMoO4 in pure-argon atmosphere.

2.
J Org Chem ; 88(8): 5015-5024, 2023 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-36791400

RESUMO

Herein, we report the direct conversion of low-concentration CO2 (15 vol %), equivalent to the CO2 concentration in the exhaust gas from a thermal power station, into carbamic acid esters (CAEs), which are precursors for pharmaceuticals, agrochemicals, and isocyanates. The reaction was performed using Si(OMe)4 as a nonmetallic regenerable reagent and 1,8-diazabicyclo[5.4.0]undec-7-ene as a CO2 capture agent and catalyst. This reaction system does not require the addition of metal complex catalysts or metal salt additives and is therefore simpler than our previously reported reaction system involving Ti(OR)4 and a Zn(II) catalyst. A variety of N-aryl, N-alkyl, and bis CAEs (precursors of polyurethane raw materials) were obtained in moderate to high yields (45-77% for 6 examples, 84-89% for 7 examples). In addition, bis CAEs were successfully synthesized from simulated exhaust gas containing impurities such as SO2, NO2, and CO or on a gram scale. We believe that this method can eliminate the use of toxic phosgene as the raw material for isocyanate production and mitigate CO2 emissions.

3.
Chemistry ; 27(72): 18066-18073, 2021 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-34779056

RESUMO

We have successfully isolated and characterized the zinc carbamate complex (phen)Zn(OAc)(OC(=O)NHPh) (1; phen=1,10-phenanthroline), formed as an intermediate during the Zn(OAc)2 /phen-catalyzed synthesis of organic carbamates from CO2 , amines, and the reusable reactant Si(OMe)4 . Density functional theory calculations revealed that the direct reaction of 1 with Si(OMe)4 proceeds via a five-coordinate silicon intermediate, forming organic carbamates. Based on these results, the catalytic system was improved by using Si(OMe)4 as the reaction solvent and additives like KOMe and KF, which promote the formation of the five-coordinated silicon species. This sustainable and effective method can be used to synthesize various N-aryl and N-alkyl carbamates, including industrially important polyurethane raw materials, starting from CO2 under atmospheric pressure.

4.
J Bone Miner Metab ; 34(2): 193-200, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25796629

RESUMO

It is unclear whether osteoclasts are present and activated in cholesteatomas. We explored the expression of messenger RNA (mRNA) for osteoclast biomarkers and regulating factors in middle ear cholesteatomas to elucidate the level of osteoclast activity in this disease. Bone powder was collected from 14 patients with cholesteatomatous and noncholesteatomatous chronic otitis media during tympanomastoidectomy, separately from cortical bone of the mastoid (clean bone powder), from bone neighboring cholesteatoma (cholesteatomatous bone powder), and from bone of the air cells and antrum of noncholesteatomatous chronic otitis media patients (noncholesteatomatous bone powder). The samples collected were soaked in TRIzol reagent, and total RNA was extracted and purified by the acid guanidinium thiocyanate-phenol-chloroform method, followed by the use of magnetic bead technology. The sample was then subjected to quantitative reverse transcription polymerase chain reaction for receptor activator of nuclear factor κB (RANK), tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), osteoclast-associated receptor (OSCAR), calcitonin receptor (CALCR), matrix metalloproteinase 9 (MMP9), receptor activator of nuclear factor κB ligand (RANKL), and osteoprotegerin (OPG). There was no significant difference in the expression of TRAP, CTSK, OSCAR, CALCR, MMP9, or OPG among the clean, cholesteatomatous, and noncholesteatomatous bone powder. On the other hand, the expression of RANK and RANKL was significantly lower in the cholesteatomatous bone powder than in the noncholesteatomatous bone powder (P = 0.003 and P = 0.028, respectively). The RANKL mRNA/OPG mRNA ratio did not differ among the three samples. These results indicate that osteoclasts are unlikely to be activated in cholesteatomas. Bone resorption mechanisms not mediated by osteoclasts may need to be reappraised in cholesteatoma research in future studies.


Assuntos
Colesteatoma da Orelha Média/patologia , Osteoclastos/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/metabolismo , Catepsina K/genética , Catepsina K/metabolismo , Colesteatoma da Orelha Média/genética , Feminino , Regulação da Expressão Gênica , Humanos , Masculino , Metaloproteinase 9 da Matriz/genética , Metaloproteinase 9 da Matriz/metabolismo , Pessoa de Meia-Idade , Osteoclastos/metabolismo , Osteoprotegerina/genética , Osteoprotegerina/metabolismo , Ligante RANK/genética , Ligante RANK/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptor Ativador de Fator Nuclear kappa-B/genética , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Receptores da Calcitonina/genética , Receptores da Calcitonina/metabolismo , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Fosfatase Ácida Resistente a Tartarato/genética , Fosfatase Ácida Resistente a Tartarato/metabolismo , Adulto Jovem
5.
Eur Arch Otorhinolaryngol ; 273(10): 3101-7, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26879994

RESUMO

We studied the effect of intratympanic steroid administration with different intervals on hearing outcomes in patients with idiopathic sudden sensorineural hearing loss (ISSNHL). The subjects were 197 consecutive patients (197 ears) with ISSNHL (hearing level ≥40 dB, interval between onset and treatment ≤30 days). They received systemic administration of prednisolone (100 mg followed by tapered doses) combined with intratympanic injection of dexamethasone (4 mg/ml). Intratympanic injection was performed once a week for 4 weeks in 105 patients (long-interval group), or 4 times in 1 week in 92 patients (short-interval group). The hearing outcomes were evaluated at two points of time: 1 week from the start of treatment, and 1-2 months after the completion of treatment when the hearing level reached a plateau. There was no significant difference in the cure rate, marked-recovery rate, recovery rate, hearing gain, hearing level, or percent hearing improvement between the long- and short-interval groups at either point of time. Multiple regression analysis also showed that the final hearing level did not depend on the interval of intratympanic steroid injection. These results indicate that the hearing outcome of ISSNHL does not improve even if the interval of intratympanic injection is shortened. This implies that a lower total number of intratympanic steroid injections may be as effective as the present protocol.


Assuntos
Dexametasona/administração & dosagem , Glucocorticoides/administração & dosagem , Perda Auditiva Neurossensorial/tratamento farmacológico , Prednisolona/administração & dosagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Audiometria de Tons Puros , Esquema de Medicação , Feminino , Audição/efeitos dos fármacos , Audição/fisiologia , Perda Auditiva Súbita/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Membrana Timpânica/efeitos dos fármacos
6.
Eur Arch Otorhinolaryngol ; 273(12): 4397-4402, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27168403

RESUMO

Ion beam therapy has enabled us to treat formerly untreatable malignant tumors. The aim of the present study was to investigate the long-term follow-up course of patients with head and neck cancers who received ion beam therapy. The subjects were 8 patients (3 men and 5 women aged 43-78 years) with head and neck cancers who visited our department from 2006 to 2015 and received ion beam therapy. Six patients received carbon ion beam therapy, and the other two patients received proton beam therapy. The medical records of the patients were retrospectively analyzed. The primary site was the nasal and paranasal sinuses in six cases, nasopharynx in one case, and external auditory canal in one case. The histological type was olfactory neuroblastoma, malignant melanoma, and adenoid cystic carcinoma in two cases each, and chondrosarcoma and squamous cell carcinoma in one case each. The exposure dose ranged from 64 to 70.4 GyE. The average follow-up period was 42.0 months. Early adverse events were generally mild, and complete therapeutic response was obtained in all cases. However, five patients developed severe late complications including craniospinal dissemination, osteoradionecrosis of the maxilla and skull base, brain necrosis, and loss of eyesight. Three patients died of distant metastasis, local recurrence and/or brain necrosis within 2 years, and four patients have been surviving with distant metastasis or severe late complications. Ion beam therapy exhibits outstanding antitumor effects, but the severe late complications of the therapy must also be recognized.


Assuntos
Carcinoma Adenoide Cístico/radioterapia , Carcinoma de Células Escamosas/radioterapia , Estesioneuroblastoma Olfatório/radioterapia , Neoplasias de Cabeça e Pescoço/radioterapia , Radioterapia com Íons Pesados , Melanoma/radioterapia , Terapia com Prótons , Adulto , Idoso , Carcinoma Adenoide Cístico/mortalidade , Carcinoma Adenoide Cístico/patologia , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Estesioneuroblastoma Olfatório/mortalidade , Estesioneuroblastoma Olfatório/patologia , Feminino , Neoplasias de Cabeça e Pescoço/mortalidade , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Melanoma/mortalidade , Melanoma/patologia , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Estudos Retrospectivos , Resultado do Tratamento
7.
Artigo em Inglês | MEDLINE | ID: mdl-26633876

RESUMO

PURPOSE: We investigated the electrical impedance and expression of tight junction components of the turbinate mucosa, nasal polyp, and normal skin. PROCEDURES: The inferior turbinate and nasal polyp of patients with chronic rhinosinusitis and the postauricular skin of patients with otitis media were examined. Electrical impedance was measured in vivo using a tissue conductance meter. Expressions of claudin-1 and tricellulin were examined by fluorescence immunohistochemistry and quantitative RT-PCR. RESULTS: Electrical impedance was higher in the skin than in the turbinate and polyp, but did not differ between the turbinate and polyp. Immunoreactivities for claudin-1 and tricellulin were seen in the epithelial/epidermal layer. Expression of claudin-1 was higher in the skin than in the turbinate and polyp. The polyp tended to show higher expression of claudin-1 but showed lower expression of tricellulin than the turbinate. The ratio of claudin-1 to tricellulin was highest in the skin and lowest in the turbinate. The correlation between expressions of the two tight junction components was strongly positive in the skin (r = 0.964) and negative (r = -0.527) in the turbinate and polyp. CONCLUSIONS: These results suggest that the roles of claudin-1 and tricellulin in barrier function may be complementary, and may thereby maintain a constant level of permeability of the mucosal tissues.


Assuntos
Impedância Elétrica , Pólipos Nasais/metabolismo , Junções Íntimas/metabolismo , Conchas Nasais/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Claudina-1/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Proteína 2 com Domínio MARVEL/metabolismo , Masculino , Pessoa de Meia-Idade , Pólipos Nasais/cirurgia , Reação em Cadeia da Polimerase em Tempo Real , Rinite/metabolismo , Rinite/cirurgia , Sinusite/metabolismo , Sinusite/cirurgia , Conchas Nasais/cirurgia
8.
J UOEH ; 38(3): 237-42, 2016 09.
Artigo em Japonês | MEDLINE | ID: mdl-27627972

RESUMO

Myringoplasty is one of the basic procedures in otologic surgery, and is important to achieve good hearing outcome. The temporal fascia is most widely used and considered to be a stable graft in this procedure, although 10-20% of patients develop reperforation after surgery, which is often hard to repair, even by revision surgery. We herein conducted revision myringoplasty using a cartilage graft to repair postoperative reperforation in 7 patients (8 ears) with chronic otitis media. The patients were 3 males and 4 females, aged 13-80 years with an average of 53.9 years. A cartilage graft was harvested from the tragus, sliced in 0.3 mm thickness with perichondrium attached on one side, and trimmed into an appropriate shape and size. The graft was then underlaid beneath the perforation and fixed with fibrin glue. The operation was Wullstein type I tympanoplasty in 5 ears and myringoplasty in 3 ears, using the temporal fascia in 7 ears and subcutaneous tissue in 1 ear. The postoperative follow-up period ranged from 16 to 44 months with an average of 30.0 months. Perforation of the tympanic membrane was successfully closed in 7 ears (87.5%). Hearing outcome was judged successful in 5 ears (62.5%) according to the criteria of the Otological Society of Japan (postoperative hearing level < 30 dB, hearing gain > 15 dB, or postoperative air-bone gap < 15 dB). These results indicate that cartilage is a stable and reliable graft material for revision myringoplasty to repair postoperative reperforation in patients with chronic otitis media.


Assuntos
Cartilagem/transplante , Miringoplastia , Otite Média/cirurgia , Perfuração da Membrana Timpânica/cirurgia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Doença Crônica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Procedimentos de Cirurgia Plástica , Recidiva , Adulto Jovem
9.
Sleep Breath ; 19(1): 85-9, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24622960

RESUMO

PURPOSE: Sleep apnea is sometimes associated with hypothyroidism, but the significance of thyroid function screening in sleep apnea patients has been controversial. In the present study, we investigated the relationship between thyroid function and sleep apnea in subjects who were suspected to have sleep apnea. METHODS: We enrolled 156 consecutive subjects suspected of having sleep apnea. Subjects included 117 men and 39 women aged 21 to 84 years. They underwent nocturnal multichannel polysomnography during a one-night hospitalization. The examined indices of sleep apnea were apnea-hypopnea index (AHI), lowest oxygen saturation, oxygen desaturation index, longest apnea duration, mean apnea duration, and the percent of apnea time to sleep time. Serum thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4) were concomitantly measured by electrochemiluminescence immunoassays. RESULTS: Three subjects (1.9 %) were diagnosed with primary hypothyroidism (high TSH and low FT4), and one subject (0.6 %) with subclinical hypothyroidism (high TSH and normal FT4). No significant difference in the level of TSH, FT3, or FT4 was seen among subjects with different severity of sleep apnea. The mean apnea duration significantly correlated with TSH in both simple and multiple regression analyses. Subjects with lower FT3 (≤3.75 pg/ml) showed longer mean apnea time compared to those with higher FT3 (>3.75 pg/ml) (24.9 ± 0.8 vs. 20.2 ± 1.2 s; P = 0.009). The other indices of sleep apnea did not show significant correlation with thyroid function. CONCLUSIONS: These results suggest that the mean apnea duration and TSH/FT3 may be helpful in understanding reciprocity between the two disease states, and for evaluating the validity of thyroid function tests in patients with sleep apnea.


Assuntos
Hipotireoidismo/epidemiologia , Hipotireoidismo/fisiopatologia , Apneia Obstrutiva do Sono/epidemiologia , Apneia Obstrutiva do Sono/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Humanos , Hipotireoidismo/diagnóstico , Japão , Masculino , Pessoa de Meia-Idade , Polissonografia , Apneia Obstrutiva do Sono/diagnóstico , Estatística como Assunto , Testes de Função Tireóidea , Tireotropina/sangue , Tiroxina/sangue , Tri-Iodotironina/sangue , Adulto Jovem
10.
Ann Otol Rhinol Laryngol ; 123(8): 571-5, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24634153

RESUMO

OBJECTIVES: The objective was to analyze the surgical outcomes of tympanoplasty with partial mastoid obliteration and soft-wall reconstruction for middle ear cholesteatoma. METHODS: Sixty-nine patients (73 ears) with fresh middle ear cholesteatomas, 42 men and 27 women aged 6 to 89 years, were retrospectively analyzed. The cholesteatomas were the pars flaccida and tensa types in 59 and 12 ears, respectively. The patients underwent canal-wall-down tympanoplasty with partial mastoid obliteration and soft-wall reconstruction. Follow-up computed tomography was performed 6 to 12 months after surgery. Hearing outcomes were evaluated by the arithmetic mean of the hearing levels at 500, 1000, and 2000 Hz. RESULTS: Residual cholesteatoma occurred in 7 ears (9.6%) and recurrent cholesteatoma in 1 ear (1.4%). No cavity problem was seen. Primary evaluation of postoperative hearing was performed 6 to 12 months after ossiculoplasy. Of the 50 ears with available audiogram in this period, the postoperative air-bone gaps were ≤ 15 dB and ≤ 20 dB in 27 (54.0%) and 37 (74.0%) ears, respectively. The postoperative hearing level was within 30 dB in 22 ears (44.0%). The hearing gain was ≥ 15 dB in 24 ears (48.0%). CONCLUSIONS: The surgical outcomes of tympanoplasty with partial mastoid obliteration and soft-wall reconstruction for middle ear cholesteatoma were satisfactory with a low incidence of cholesteatoma recidivism and tolerable postoperative hearing without cavity problems.


Assuntos
Colesteatoma da Orelha Média/cirurgia , Meato Acústico Externo/cirurgia , Orelha Média/cirurgia , Processo Mastoide/cirurgia , Timpanoplastia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Audiometria , Condução Óssea , Criança , Fáscia/transplante , Feminino , Perda Auditiva/etiologia , Perda Auditiva/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos , Membrana Timpânica/cirurgia , Adulto Jovem
11.
Ann Otol Rhinol Laryngol ; 123(12): 821-5, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24944278

RESUMO

OBJECTIVE: This study aimed to create a multiple regression model for predicting hearing outcomes of idiopathic sudden sensorineural hearing loss (ISSNHL). METHODS: The participants were 205 consecutive patients (205 ears) with ISSNHL (hearing level ≥ 40 dB, interval between onset and treatment ≤ 30 days). They received systemic steroid administration combined with intratympanic steroid injection. Data were examined by simple and multiple regression analyses. Three hearing indices (percentage hearing improvement, hearing gain, and posttreatment hearing level [HLpost]) and 7 prognostic factors (age, days from onset to treatment, initial hearing level, initial hearing level at low frequencies, initial hearing level at high frequencies, presence of vertigo, and contralateral hearing level) were included in the multiple regression analysis as dependent and explanatory variables, respectively. RESULTS: In the simple regression analysis, the percentage hearing improvement, hearing gain, and HLpost showed significant correlation with 2, 5, and 6 of the 7 prognostic factors, respectively. The multiple correlation coefficients were 0.396, 0.503, and 0.714 for the percentage hearing improvement, hearing gain, and HLpost, respectively. Predicted values of HLpost calculated by the multiple regression equation were reliable with 70% probability with a 40-dB-width prediction interval. CONCLUSION: Prediction of HLpost by the multiple regression model may be useful to estimate the hearing prognosis of ISSNHL.


Assuntos
Dexametasona/administração & dosagem , Glucocorticoides/administração & dosagem , Perda Auditiva Neurossensorial/tratamento farmacológico , Análise de Regressão , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Audição , Perda Auditiva Neurossensorial/complicações , Perda Auditiva Neurossensorial/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento , Vertigem/complicações , Adulto Jovem
12.
ACS Omega ; 9(24): 25879-25886, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38911772

RESUMO

Dialkyl carbonates (DRCs) are valuable compounds widely used in the industry. The synthesis of DRC from CO2 has attracted interest as an alternative to the current method, which uses phosgene. However, the reported approaches for DRC synthesis from CO2 requires high-pressure and high-concentration CO2, resulting in elevated costs associated with CO2 purification and manufacturing facilities. In this report, we present an environmentally friendly method for producing DRC from low-concentration and low-pressure CO2 via a dehydration condensation approach without the use of halogenated alkylating agents. This method involves the formation of monoalkyl carbonate [BASE-H][ROC(O)O] using a strong organic base and alcohols, tetraalkyl orthosilicates as dehydrating agents, and CeO2 as the catalyst. Using the method, 39 and 30% of diethyl carbonate yields were accomplished with only 100 and 15 vol % CO2 (CO2/N2 = 15:85) gas bubbling at atmospheric pressure, even under reaction conditions with no large excess of either CO2, alcohol, or dehydration agent.

13.
Nat Commun ; 14(1): 8074, 2023 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-38065999

RESUMO

Berry phases in both momentum and real space cause transverse motion in itinerant electrons, manifesting various off-diagonal transport effect such anomalous and topological Hall effects. Although these Hall effects are isotropic within the plane perpendicular to the fictitious magnetic field, here, we report the manifestation of the anisotropic linear anomalous Hall effect (AHE) in the spinel oxide NiCo2O4 epitaxial film. The unconventional Hall effect indicates a quadrupole dependence on the in-plane current direction being added to the uniform AHE. Moreover, its sign can be manipulated just by magnetic-field cooling. The anisotropic effect is attributed to an electron nematic state originating from a deformed electronic state owing to an extended magnetic toroidal quadrupole and ferrimagnetic order.

14.
Commun Chem ; 4(1): 66, 2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-36697711

RESUMO

To reduce anthropogenic carbon dioxide (CO2) emissions, it is desirable to develop reactions that can efficiently convert low concentrations of CO2, present in exhaust gases and ambient air, into industrially important chemicals, without involving any expensive separation, concentration, compression, and purification processes. Here, we present an efficient method for synthesizing urea derivatives from alkyl ammonium carbamates. The carbamates can be easily obtained from low concentrations of CO2 as present in ambient air or simulated exhaust gas. Reaction of alkyl ammonium carbamates with 1,3-dimethyl-2-imidazolidinone solvent in the presence of a titanium complex catalyst inside a sealed vessel produces urea derivatives in high yields. This reaction is suitable for synthesizing ethylene urea, an industrially important chemical, as well as various cyclic and acyclic urea derivatives. Using this methodology, we also show the synthesis of urea derivatives directly from low concentration of CO2 sources in a one-pot manner.

16.
Chem Sci ; 10(10): 3080-3088, 2019 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-30996890

RESUMO

CO2 capture at low concentration by catalysts is potentially useful for developing photocatalytic and electrocatalytic CO2 reduction systems. We investigated the CO2-capturing abilities of two complexes, fac-Mn(X2bpy)(CO)3(OCH2CH2NR2) and fac-Re(X2bpy)(CO)3(OCH2CH2NR2) (X2bpy = 4,4'-X2-2,2-bipyridine and R = -CH2CH2OH), which work as efficient catalysts for CO2 reduction. Both complexes could efficiently capture CO2 even from Ar gas containing only low concentration of CO2 such as 1% to be converted into fac-M(X2bpy)(CO)3(OC(O)OCH2CH2NR2) (M = Mn and Re). These CO2-capturing reactions proceeded reversibly and their equilibrium constants were >1000. The substituents of X2bpy strongly affected the CO2-capturing abilities of both Mn and Re complexes. The density functional theory (DFT) calculation could be used to estimate the CO2-capturing abilities of the metal complexes in the presence of triethanolamine.

17.
Chem Sci ; 10(6): 1597-1606, 2019 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-30842822

RESUMO

Utilization of low concentration CO2 contained in the exhaust gases from various industries and thermal power stations without the need for energy-consuming concentration processes should be an important technology for solving global warming and the shortage of fossil resources. Here we report the direct electrocatalytic reduction of low concentration CO2 by a Re(i)-complex catalyst that possesses CO2-capturing ability in the presence of triethanolamine. The reaction rate and faradaic efficiency of CO2 reduction were almost the same when using Ar gas containing 10% CO2 or when using pure CO2 gas, and the selectivity of CO formation was very high (98% at 10% CO2). At a concentration of 1% CO2, the Re(i) complex still behaved as a good electrocatalyst; 94% selectivity of CO formation and 85% faradaic efficiency were achieved, and the rate of CO formation was 67% compared to that when using pure CO2 gas. The electrocatalysis was due to the efficient insertion of CO2 into the Re(i)-O bond in fac-[Re(dmb)(CO)3{OC2H4N(C2H4OH)2}] (dmb = 4,4'-dimethyl-2,2'-bipyridine).

18.
Phys Rev E Stat Nonlin Soft Matter Phys ; 77(2 Pt 1): 021503, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18352030

RESUMO

Glassy dynamics was investigated for thin films of atactic polystyrene by complex electric capacitance measurements using dielectric relaxation spectroscopy. During the isothermal aging process the real part of the electric capacitance increased with time, whereas the imaginary part decreased with time. It follows that the aging time dependences of real and imaginary parts of the electric capacitance were primarily associated with change in volume (film thickness) and dielectric permittivity, respectively. Further, dielectric permittivity showed memory and rejuvenation effects in a similar manner to those observed for poly(methyl methacrylate) thin films. On the other hand, volume did not show a strong rejuvenation effect.

19.
Ann Otol Rhinol Laryngol ; 127(4): 235-240, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29411622

RESUMO

OBJECTIVE: We studied the effect of intratympanic steroid administration with different total injection times on hearing outcomes in patients with idiopathic sudden sensorineural hearing loss (ISSNHL). METHODS: The subjects were 191 consecutive patients (192 ears) with ISSNHL (hearing level ≥40 dB, interval between onset and treatment ≤30 days). They received systemic prednisolone (100 mg followed by tapered doses) combined with intratympanic injection of dexamethasone (4 mg/ml). Intratympanic injection was performed 4 times (days 1, 2, 4, and 7) in 92 patients (92 ears) or 2 times (days 1 and 2) in 99 patients (100 ears). The hearing outcomes were evaluated at 1 week from the start of treatment and 1 to 2 months after the completion of treatment. RESULTS: There was no significant difference in hearing outcomes between the 4- and 2-injection groups at either time point. Multiple regression analysis also showed that the hearing level after treatment did not depend on the total number of intratympanic steroid injections. CONCLUSION: These results indicate that a protocol using only 2 intratympanic steroid injections exerts a sufficient effect on the hearing outcomes of ISSNHL. This simplified treatment protocol would be greatly beneficial to relieve the physical and mental stress of patients.


Assuntos
Dexametasona/administração & dosagem , Perda Auditiva Neurossensorial , Perda Auditiva Súbita , Audição/efeitos dos fármacos , Prednisolona/administração & dosagem , Recuperação de Função Fisiológica/efeitos dos fármacos , Audiometria de Tons Puros/métodos , Esquema de Medicação , Monitoramento de Medicamentos/métodos , Feminino , Glucocorticoides/administração & dosagem , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/tratamento farmacológico , Perda Auditiva Neurossensorial/fisiopatologia , Perda Auditiva Súbita/diagnóstico , Perda Auditiva Súbita/tratamento farmacológico , Perda Auditiva Súbita/fisiopatologia , Humanos , Injeção Intratimpânica/métodos , Japão , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento
20.
Am J Rhinol Allergy ; 32(4): 217-227, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29676177

RESUMO

Background Airway mucociliary transport is an important function for the clearance of inhaled foreign particulates in the respiratory tract. The present study aimed at investigating the regulatory mechanism of acetylcholine (Ach)-induced ciliary beat of the human nasal mucosa in ex vivo. Methods The inferior turbinate mucosa was collected from patients with chronic hypertrophic rhinitis during endoscopic surgery. The mucosa was cut into thin strips, and ciliary movement was observed under a phase-contrast light microscope with a high-speed digital video camera. The sample was alternatively subjected to scanning electron microscopic observation. Results Cilia on the turbinate epithelium were well preserved at the ultrastructural level. The baseline ciliary beat frequency (CBF) was 6.45 ± 0.32 Hz. CBF was significantly increased by stimulation with 100 µM Ach and 100 µM adenosine triphosphate. The Ach-induced CBF increase was completely inhibited by removing extracellular Ca2+. Significant inhibition of the Ach-induced CBF was also observed by the addition of 1 µM atropine, 40 µM 2-aminoethoxydiphenyl borate (inositol trisphosphate [IP3] receptor antagonist), 10 µM carbenoxolone (pannexin-1 blocker), 1 mM probenecid (pannexin-1 blocker), 100 µM pyridoxalphosphate-6-azophenyl-20,40-disulfonic acid (P2X antagonist), and 300 µM flufenamic acid (connexin blocker). Meanwhile, 30 nM bafilomycin A1 (vesicular transport inhibitor) did not inhibit the Ach-induced CBF increase. CONCLUSIONS: These results indicate that the regulatory mechanism of the Ach-induced ciliary beat is dependent on extracellular Ca2+ and involves the muscarinic Ach receptor, IP3 receptor, pannexin-1 channel, purinergic P2X receptor, and connexin channel. We proposed a tentative intracellular signaling pathway of the Ach-induced ciliary beat, in which the pannexin-1-P2X unit may play a central role in ciliary beat regulation.


Assuntos
Cílios/fisiologia , Conexinas/metabolismo , Depuração Mucociliar/fisiologia , Mucosa Nasal/fisiologia , Proteínas do Tecido Nervoso/metabolismo , Receptores Purinérgicos P2X/metabolismo , Rinite/imunologia , Acetilcolina/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Carbenoxolona/farmacologia , Células Cultivadas , Doença Crônica , Conexinas/antagonistas & inibidores , Feminino , Humanos , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Masculino , Pessoa de Meia-Idade , Mucosa Nasal/patologia , Proteínas do Tecido Nervoso/antagonistas & inibidores , Transdução de Sinais , Conchas Nasais/patologia , Adulto Jovem
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