RESUMO
In electrides, interstitial anionic electrons (IAEs) in the quantized energy levels at cavities of positively charged lattice framework possess their own magnetic moment and interact with each or surrounding cations, behaving as quasi-atoms and inducing diverse magnetism. Here, we report the reversible structural and magnetic transitions by the substitution of the quasi-atomic IAEs in the ferromagnetic two-dimensional [Gd2C]2+·2e- electride with hydrogens and subsequent dehydrogenation of the canted antiferromagnetic Gd2CHy (y > 2.0). It is demonstrated that structural and magnetic transitions are strongly coupled by the presence or absence of the magnetic quasi-atomic IAEs and non-magnetic hydrogen anions in the interlayer space, which dominate exchange interactions between out-of-plane Gd-Gd atoms. Furthermore, the magnetic quasi-atomic IAEs are inherently conserved by the hydrogen desorption from the P[Formula: see text] 1m structured Gd2CHy, restoring the original ferromagnetic state of the R[Formula: see text]m structured [Gd2C]2+·2e- electride. This variable density of magnetic quasi-atomic IAEs enables the quantum manipulation of floating electron phases on the electride surface.
RESUMO
Catalytic transformation of methane (CH4) into methanol in a single step is a challenging issue for the utilization of CH4. We present a direct method for converting CH4 into methanol with high selectivity over a Pt/CeO2 catalyst which contains ionic Pt2+ species supported on a CeO2 nanoparticle. The Pt/CeO2 catalyst reproducibly yielded 6.27 mmol/g of Pt with a selectivity of over 95% at 300 °C when CH4 and CO are used as reactants, while the catalyst had a lower activity when using only CH4 without CO. Active lattice oxygen created on the Pt and CeO2 interface provides selective reaction pathways for the conversion of CH4 to methanol. Based on high-angle annular dark-field scanning transmission electron microscopy, x-ray photoelectron spectroscopy, x-ray absorption near-edge structure, extended x-ray absorption fine structure, catalytic studies, and density functional theory calculations, we propose a mechanistic pathway involving CH4 activation at the active site in the vicinity of Pt2+ species.
RESUMO
Methyl ammonium methyl carbamate (MAC), formulated as CH3NH3 +CH3NHCO2 -, was synthesized by reacting liquid methylamine with supercritical CO2, and its structure was refined by single-crystal X-ray diffraction. MAC is a white crystalline salt and is as reactive as methylamine, and is a very efficient alternative to toxic methylamine. We were able to produce hybrid perovskite MAPbI3 (MA = methyl ammonium) by grinding MAC with PbI2 and I2 at room temperature, followed by storing the mixed powder. Moreover, this one-pot method is easily scalable for the large-scale synthesis of MAPbI3 in a small vessel. We have also investigated the reactivity of MAC towards aromatic aldehydes in the absence of solvent. The solventless reactions afforded imines as exclusive products with over 97% yield, which show higher selectivity than the methylamine-based synthesis. Complete conversions were typically accomplished within 3 h at 25 °C. The results of this study emphasize the importance of solid carbamates such as MAC to develop an environmentally friendly process for the synthesis of various amine-based materials on the industrial scale.
RESUMO
Aqueous amines are currently the most promising solution for large-scale CO2 capture from industrial sources. However, molecular design and optimization of amine-based solvents have proceeded slowly due to a lack of understanding of the underlying reaction mechanisms. Unique and unexpected reaction mechanisms involved in CO2 absorption into aqueous hydrazine are identified using 1H, 13C, and 15N NMR spectroscopy combined with first-principles quantum-mechanical simulations. We find production of both hydrazine mono-carbamate (NH2-NH-COO-) and hydrazine di-carbamate (-OOC-NH-NH-COO-), with the latter becoming more populated with increasing CO2 loading. Exchange NMR spectroscopy also demonstrates that the reaction products are in dynamic equilibrium under ambient conditions due to CO2 exchange between mono-carbamate and di-carbamate as well as fast proton transfer between un-protonated free hydrazine and mono-carbamate. The exchange rate rises steeply at high CO2 loadings, enhancing CO2 release, which appears to be a unique property of hydrazine in aqueous solution. The underlying mechanisms of these processes are further evaluated using quantum mechanical calculations. We also analyze and discuss reversible precipitation of carbamate and conversion of bicarbonate to carbamates. The comprehensive mechanistic study provides useful guidance for optimal design of amine-based solvents and processes to reduce the cost of carbon capture. Moreover, this work demonstrates the value of a combined experimental and computational approach for exploring the complex reaction dynamics of CO2 in aqueous amines.
RESUMO
BACKGROUND: The aim of this study was to evaluate the results of sleep-wake cycle monitoring using amplitude-integrated EEG (aEEG) and neuroimaging in newborn infants with a possible perinatal hypoxic insult, investigate the correlation between the findings, and determine the relevance of the findings to reasonably predict neurological outcome. METHODS: aEEG was recorded among newborn infants suspected of perinatal asphyxia between November, 2014 and June, 2015 in one neonatal intensive care unit facility. Brain imaging with serial ultrasonography and MRI when available were performed, and the infants were divided into two groups according to findings and potential neurological outcome: Group I (favorable findings) and Group II (severe findings such as high grade intraventricular hemorrhage, cerebral infarction or white matter injury). Established sleep-wake cycle times after birth was compared between the two groups. RESULTS: Among 107 newborn infants, 85 subjects were classified as Group I and the remaining 22 subjects as Group II. The total number of aEEG sessions was 207 and recording time was 2,796 h with a mean of 14.43 ± 13.40 h per study. Estimated times of cyclicity were earlier in Group I (113.34 h, 95 % CI 82.31-144.37) as compared to Group II (504.39 h, 95 % CI 319.91-688.88; p < 0.001). CONCLUSIONS: Delayed cyclicity on aEEG has a strong correlation with unfavorable brain neuroimages in newborns with possible perinatal asphyxia. If sleep-wake cycles do not appear during initial period after birth, follow-up aEEG studies are recommended. TRIAL REGISTRATION: Retrospectively registered Registration number: BD 2015-148 Name of registry: amplitude integrated EEG in neonate Date of registration: September 9, 2015.
Assuntos
Asfixia Neonatal/diagnóstico , Eletroencefalografia , Neuroimagem , Transtornos do Sono do Ritmo Circadiano/diagnóstico , Feminino , Humanos , Recém-Nascido , MasculinoRESUMO
PURPOSE: Bronchopulmonary dysplasia (BPD) is characterized by inflammation with proteolytic damage to the lung extracellular matrix. The results from previous studies are inconsistent regarding the role of proteinases and antiproteinases in the development of BPD. The aim of the present study was to investigate whether matrix metalloproteinase (MMP)-8, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-2, and TIMP-1 levels in the serum of preterm infants at birth are related to the development of BPD. METHODS: Serum was collected from 62 preterm infants at birth and analyzed for MMP-8, MMP-9, TIMP-2, and TIMP-1 by using enzyme-linked immunosorbent assay. MMPs and TIMPs were compared in BPD (n=24) and no BPD groups (n=38). Clinical predictors of BPD (sex, birth weight, gestational age, etc.) were assessed for both groups. The association between predictors and outcome, BPD, was assessed by using multivariate logistic regression. RESULTS: Sex, birth weight, and mean gestational age were similar between the groups. BPD preterm infants had significantly lower TIMP-2 levels at birth compared with no BPD preterm infants (138.1±23.0 ng/mL vs. 171.8±44.1 ng/mL, P=0.027). No significant difference was observed in MMP-8, MMP-9, and TIMP-1 levels between the two groups. Multivariate logistic regression analysis indicated that the TIMP-2 levels were predictive of BPD after adjusting for sex, birth weight, gestational age, proteinuric preeclampsia, and intraventricular hemorrhage (ß=-0.063, P=0.041). CONCLUSION: Low TIMP-2 serum levels at birth may be associated with the subsequent development of BPD in preterm infants.
Assuntos
Quimerismo , Córion/irrigação sanguínea , Fertilização in vitro , Placenta/irrigação sanguínea , Testículo/anormalidades , Gêmeos Dizigóticos/genética , Adulto , Atrofia , Feminino , Humanos , Recém-Nascido , Cariotipagem , Masculino , Gravidez , Testículo/diagnóstico por imagem , Testículo/patologia , Ultrassonografia Pré-NatalRESUMO
In up to 40% of systemic mastocytosis (SM) cases, an associated clonal hematological non-mast cell lineage disease such as AML is diagnosed before, simultaneously with, or after the diagnosis of SM. A 40-yr-old man was diagnosed with AML with t(8;21)(q22;q22). Mast cells were not noted at diagnosis, but appeared as immature forms at relapse. After allogeneic hematopoietic stem cell transplantation (HSCT), leukemic myeloblasts were not observed; however, neoplastic metachromatic blasts strikingly proliferated during the state of bone marrow aplasia, and finally, aleukemic mast cell leukemia developed. As the disease progressed, we observed serial morphologic changes from immature mast cells with myeloblasts to only metachromatic blasts and atypical mast cells as mast cell leukemia; FISH analysis showed that the neoplastic mast cells originated from the same clone as the leukemic myeloblasts of AML.
Assuntos
Transplante de Células-Tronco Hematopoéticas , Leucemia Mieloide Aguda/diagnóstico , Mastocitose Sistêmica/diagnóstico , Adulto , Células da Medula Óssea/patologia , Cromossomos Humanos Par 21 , Cromossomos Humanos Par 8 , Humanos , Hibridização in Situ Fluorescente , Leucemia de Mastócitos/diagnóstico , Leucemia de Mastócitos/etiologia , Leucemia Mieloide Aguda/complicações , Leucemia Mieloide Aguda/terapia , Leucócitos Mononucleares/patologia , Masculino , Mastocitose Sistêmica/etiologia , Recidiva , Translocação Genética , Transplante HomólogoRESUMO
BACKGROUND: Chromosome 22q11.2 microduplications are extremely rarely detected; in comparison, the deletion of same region, known as the DiGeorge/velocardiofacial syndrome, occurs more frequently. Thyroid anomalies commonly occur in patients with 22q11.2 deletion syndrome, however few reports of thyroid anomalies associated with 22q11.2 microduplication have been published thus far. CASE REPORT: We present a case of a male infant who was prenatally diagnosed with 22q11.2 microduplication and was found to have congenital hypothyroidism due to thyroid hemiagenesis after birth. Moreover, the baby had bilateral hearing impairment, bilateral cryptorchidism, and a rotated penis. At the age of 2 years, the infant was euthyroid with levothyroxine replacement, but he showed significant developmental delay. CONCLUSIONS: To our knowledge, this is the first case of congenital hypothyroidism with thyroid hemiagenesis in a patient showing 22q11.2 microduplication. Thyroid dysgenesis could be an additional clinical feature shared by the 22q11.2 microduplication and deletion syndrome, suggesting that the duplication and deletion of a gene may result in a common phenotype. Thyroid dysgenesis should be considered in the evaluation and management of patients with this genomic disorder.
Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 22 , Síndrome de DiGeorge/genética , Glândula Tireoide/anormalidades , Anormalidades Múltiplas/genética , Hipotireoidismo Congênito/genética , Duplicação Gênica , Humanos , Hibridização in Situ Fluorescente , Lactente , Recém-Nascido , MasculinoRESUMO
The clinical outcomes of acute promyelocytic leukemia (APL) have improved greatly, but treatment failure still occurs. Identification of patients with poor prognosis is fundamental, and we propose a new clinical prognostic system (CBC-score) consisting of WBC, platelet count, and hemoglobin level. Between 1995 and 2009, 156 patients with APL from seven institutes in Korea were retrospectively reviewed. In the new CBC-score system, each of the following (WBC ≥ 10 × 109/L, platelet <40 × 109/L, hemoglobin <8.0 g/dL) was considered as a risk factor; the sum of each was designated as the CBC-score. With a median follow-up of 8.4 years, the complete remission (CR) rate was 81.4 % (127/156), while 24 (15.4 %) were considered as treatment failures due to early death (ED). The 5-year overall survival (OS), leukemia-free survival, and cumulative incidence of relapse were 73.8, 82.8, and 13.5 %, respectively. Compared to the individual CBC parameters, combined prognostic systems such as PETHEMA or CBC-score provided better prognostic stratification. Compared to PETHEMA stratification, the proposed prognostic CBC-score system showed better stratification of APL patients in terms of CR rates (p = 0.004), OS (p = 0.004), and ED (p = 0.008). This retrospective study suggests that the proposed CBC-score may provide better prognostic stratification of APL patients.
Assuntos
Hemoglobinas/metabolismo , Leucemia Promielocítica Aguda/sangue , Leucemia Promielocítica Aguda/mortalidade , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Seguimentos , Hemoglobinas/análise , Humanos , Leucemia Promielocítica Aguda/terapia , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Estudos Retrospectivos , Taxa de SobrevidaRESUMO
Neonatal diabetes mellitus (NDM) is a rare disease requiring insulin treatment. Its treatment is primarily focused on maintaining adequate glycemic control and avoiding hypoglycemia. Although insulin pump therapy is frequently administered to adults and children, there is no consensus on the use of insulin pumps in NDM. A 10 day-old female infant was referred to us with intrauterine growth retardation and poor weight gain. Hyperglycemia was noted, and continuous intravenous insulin infusion was initiated. However, the patient's serum glucose levels fluctuated widely, and maintaining the intravenous route became difficult within the following weeks. Continuous subcutaneous insulin infusion with an insulin pump was introduced on the twenty-fifth day of life, and good glycemic control was achieved without any notable adverse effects including hypoglycemia. We suggest that the insulin pump is a safe and effective mode for treating NDM and its early adoption may shorten the length of hospital stays in patients with NDM.
RESUMO
BACKGROUND: Transient tachypnea of the newborn (TTN) is a clinical syndrome associated with respiratory distress usually seen shortly after delivery in infants. This study aims to determine the risk factors predicting treatment outcomes in infants with TTN. METHODS: Data from 236 infants diagnosed with TTN during the study period were evaluated retrospectively. Logistic regression analyses were performed to select significant risk factor for prognosis (prolonged oxygen therapy, application of mechanical ventilator, and prolonged hospital stay) of TTN among components of clinical variables. RESULTS: Of the 236 TTN infants, 111 (47.0%) infants were delivered via cesarean section (CS) without labor, 29 (12.3%) infants were delivered via CS with labor, and 96 (40.7%) were delivered via vaginal birth. Lower Apgar score at 1 min (OR: 3.03; 95%CI: 1.25-7.36) and lower umbilical artery pH (OR: 4.00; 95%CI 1.55-10.49) were associated with a significantly increased risk for mechanical ventilator care. Also, late-preterm delivery (OR: 4.70; 95%CI: 2.11-10.49) was independently associated with risk of prolonged duration of hospital stay. CONCLUSIONS: Late-preterm delivery, lower initial umbilical artery pH (<7.25), and lower Apgar score at 1 min were independently associated with poor prognostic treatment outcomes in infants with TTN.
Assuntos
Oxigenoterapia Hiperbárica/métodos , Respiração Artificial/métodos , Síndrome do Desconforto Respiratório do Recém-Nascido/complicações , Taquipneia Transitória do Recém-Nascido/etiologia , Feminino , Seguimentos , Idade Gestacional , Humanos , Incidência , Recém-Nascido , Tempo de Internação/tendências , Masculino , Prognóstico , República da Coreia/epidemiologia , Síndrome do Desconforto Respiratório do Recém-Nascido/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Taquipneia Transitória do Recém-Nascido/epidemiologia , Taquipneia Transitória do Recém-Nascido/terapiaRESUMO
A dual catalyst containing Pd and CuFe(2)O(4) nanoparticles in a silica shell exhibits >98% conversion of arylacetylenes to related styrenes with selectivity greater than 98%, which are better than those obtained using a commercial Lindlar catalyst. The excellent synergy was likely a result of the proximal interaction between Pd and CuFe(2)O(4) nanoparticles.
RESUMO
Highly conjugated azines were prepared by solid state grinding of solid hydrazine and carbonyl compounds such as aldehydes and ketones, using a mortar and a pestle. Complete conversion to the azine product is generally achieved at room temperature within 24 h, without using solvents or additives. The solid-state reactions afford azines as the sole products with greater than 97% yield, producing only water and carbon dioxide as waste.
Assuntos
Aldeídos/química , Compostos Azo/síntese química , Hidrazinas/química , Cetonas/química , Compostos Azo/química , Catálise , Técnicas de Química Combinatória , Estrutura MolecularRESUMO
A solid hydrazine was isolated as a crystalline powder by reacting aqueous hydrazine with supercritical CO(2). Its structure determined by single crystal X-ray diffraction shows a zwitterionic form of NH(3)(+)NHCO(2)(-). The solid hydrazine is remarkably stable but is as reactive as liquid hydrazine even in the absence of solvents.
Assuntos
Dióxido de Carbono/química , Hidrazinas/química , Modelos Moleculares , Conformação MolecularRESUMO
BACKGROUND: 3q21q26 syndrome includes chromosomal abnormalities of inv(3)(q21q26), t(3;3) (q21;q26), and ins(3;3)(q26;q21q26). It causes hematological diseases by the leukemogenic mechanism that the enhancer of ribophorin I gene in 3q21 induces the transcription of ecotropic viral integration site-1 gene in 3q26. Recently, it has been proposed that the 3q21q26 syndrome may be preceded by diabetes insipidus (DI), particularly when combined with monosomy 7, and is a unique disease entity. METHODS: From May 2001 to June 2006, a total of 5 patients with hematologic malignancy were found to have 3q21q26 syndrome and monosomy 7. Laboratory findings, clinical data, and association with DI were investigated. RESULTS: The rearrangement type of 3q21q26 was inv(3)(q21q26) in four patients and t(3;3)(q21; q26) in one. These patients' French American British types were AML M1, M2, M4 and M7, showing evident dysmegakaryopoiesis. Aberrant antigenic expressions of CD7 and CD56 were observed. The platelet count was relatively high as AML. All the five patients were refractory or in early relapse. Patient 5 was diagnosed with AML M7 20 days after being diagnosed with DI. While DI was well controlled with oral desmopressin, leukemia was refractory to chemotherapy. CONCLUSIONS: This study supports the recent opinion that 3q21q26 syndrome with monosomy 7 combined with DI is a disease of unique characteristics. In the relation between DI and monosomy 7 or 3q21q26 syndrome, there has been no explanation about how acquired abnormality of hematopoietic cells affects production of DDAVP by neurohormonal cells in hypothalamus. The mechanism needs further study, and this research should contribute to the understanding of genetic roles in leukemia appearing in different forms.
Assuntos
Transtornos Cromossômicos/complicações , Transtornos Cromossômicos/diagnóstico , Cromossomos Humanos Par 3 , Diabetes Insípido Neurogênico/complicações , Neoplasias Hematológicas/complicações , Adulto , Transtornos Cromossômicos/genética , Inversão Cromossômica , Feminino , Humanos , Cariotipagem , Masculino , Pessoa de Meia-Idade , Monossomia , Prognóstico , Síndrome , Translocação GenéticaRESUMO
Behçet's disease with concomitant thrombotic thrombocytopenic purpura (TTP), coronary artery stenosis and coronary artery pseudo aneurysm is rare. Here we report a case of Behçet's disease with several cardiovascular complications, namely: pericarditis, deep vein thrombosis (DVT), TTP, coronary artery stenosis, and a coronary artery pseudo aneurysm. A 37-year-old female presented with sudden dyspnea and syncope at our emergency room and underwent pericardiectomy and pericardial window formation for the diagnosis of cardiac tamponade with acute hemorrhagic pericarditis. Thereafter, TTP and DVT complicated her illness. After confirmation of Behçet's disease on the basis of a history of recurrent oral and genital ulcers and erythema nodosum, remission was achieved after treatment with methylprednisolone pulse therapy, colchicine, catheter directed thrombolysis and thrombectomy. However, whilst maintaining anticoagulation therapy, a newly developed pericardial aneurysmal dilatation was noted on follow-up radiologic evaluation. Further evaluation revealed right coronary artery stenosis and a left coronary artery pseudo aneurysm; these additional problems were treated with the nonsurgical insertion of an endovascular graft stent. At the time of writing three months later after stent insertion, the aneurysm has continued to regress and no additional complications have intervened with combined immunosuppressive therapy.