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1.
Diagnostics (Basel) ; 13(24)2023 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-38132254

RESUMO

Laryngeal cancer poses a significant global health burden, with late-stage diagnoses contributing to reduced survival rates. This study explores the application of deep convolutional neural networks (DCNNs), specifically the Densenet201 architecture, in the computer-aided diagnosis of laryngeal cancer using laryngoscopic images. Our dataset comprised images from two medical centers, including benign and malignant cases, and was divided into training, internal validation, and external validation groups. We compared the performance of Densenet201 with other commonly used DCNN models and clinical assessments by experienced clinicians. Densenet201 exhibited outstanding performance, with an accuracy of 98.5% in the training cohort, 92.0% in the internal validation cohort, and 86.3% in the external validation cohort. The area under the curve (AUC) values consistently exceeded 92%, signifying robust discriminatory ability. Remarkably, Densenet201 achieved high sensitivity (98.9%) and specificity (98.2%) in the training cohort, ensuring accurate detection of both positive and negative cases. In contrast, other DCNN models displayed varying degrees of performance degradation in the external validation cohort, indicating the superiority of Densenet201. Moreover, Densenet201's performance was comparable to that of an experienced clinician (Clinician A) and outperformed another clinician (Clinician B), particularly in the external validation cohort. Statistical analysis, including the DeLong test, confirmed the significance of these performance differences. Our study demonstrates that Densenet201 is a highly accurate and reliable tool for the computer-aided diagnosis of laryngeal cancer based on laryngoscopic images. The findings underscore the potential of deep learning as a complementary tool for clinicians and the importance of incorporating advanced technology in improving diagnostic accuracy and patient care in laryngeal cancer diagnosis. Future work will involve expanding the dataset and further optimizing the deep learning model.

3.
BMC Musculoskelet Disord ; 23(1): 933, 2022 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-36280811

RESUMO

BACKGROUND: With the increasing number of studies on osteoporosis and muscle adipose tissue, existing studies have shown that skeletal muscle tissue and adipose tissue are closely related to osteoporosis by dual-energy x-ray absorptiometry (DXA) measurement. However, few studies have explored whether the skeletal muscle and adipose tissue index measured at the lumbar spine 3 (L3) level are closely related to bone mineral density (BMD) and can even predict osteoporosis. Therefore, this study aimed to prove whether skeletal muscle and adipose tissue index measured by computed tomography (CT) images based on a single layer are closely related to BMD. METHODS: A total of 180 participants were enrolled in this study to obtain skeletal muscle index (SMI), psoas muscle index (PMI), subcutaneous fat index (SFI), visceral fat index (VFI), and the visceral-to-subcutaneous ratio of the fat area (VSR) at L3 levels and divide them into osteoporotic and normal groups based on the T-score of DXA. Spearman rank correlation was used to analyze the correlation between SMI, PMI, SFI, VFI, VSR, and BMD. Similarly, spearman rank correlation was also used to analyze the correlation between SMI, PMI, SFI, VFI, VSR, and the fracture risk assessment tool (FRAX). Receiver operating characteristic (ROC) was used to analyze the efficacy of SMI, PMI, SFI, VFI, and VSR in predicting osteoporosis. RESULTS: BMD of L1-4 was closely correlated with SMI, PMI, VFI and VSR (r = 0.199 p = 0.008, r = 0.422 p < 0.001, r = 0.253 p = 0.001, r = 0.310 p < 0.001). BMD of the femoral neck was only correlated with PMI and SFI (r = 0.268 p < 0.001, r = - 0.164 p-0.028). FRAX (major osteoporotic fracture) was only closely related to PMI (r = - 0.397 p < 0.001). FRAX (hip fracture) was closely related to SMI and PMI (r = - 0.183 p = 0.014, r = - 0.353 p < 0.001). Besides, FRAX (major osteoporotic fracture and hip fracture) did not correlate with VFI, SFI, and VSR. SMI and PMI were statistically significant, with the area under the curve (AUC) of 0.400 (95% confidence interval 0.312-0.488 p = 0.024) and 0.327 (95% confidence interval 0.244-0.410 p < 0.001), respectively. VFI, SFI, and VSR were not statistically significant in predicting osteoporosis. CONCLUSIONS: This study demonstrated that L3-based muscle index could assist clinicians in the diagnosis of osteoporosis to a certain extent, and PMI is superior to SMI in the diagnosis of osteoporosis. In addition, VFI, SFI, and VSR do not help clinicians to diagnose osteoporosis well.


Assuntos
Fraturas do Quadril , Osteoporose , Fraturas por Osteoporose , Humanos , Fraturas por Osteoporose/diagnóstico , Músculos Psoas/diagnóstico por imagem , Fatores de Risco , Medição de Risco/métodos , Osteoporose/diagnóstico por imagem , Absorciometria de Fóton/métodos , Densidade Óssea/fisiologia , Fraturas do Quadril/diagnóstico , Vértebras Lombares/diagnóstico por imagem , Tomografia Computadorizada por Raios X
4.
Nat Commun ; 13(1): 4145, 2022 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-35842422

RESUMO

Isocyanides are common compounds in fine and bulk chemical syntheses. However, the direct addition of isocyanide to simple unactivated cyclopropene via transition metal catalysis is challenging. Most of the current approaches focus on 1,1-insertion of isocyanide to M-R or nucleophilc insertion. That is often complicated by the competitive homo-oligomerization reactivity occurring at room temperature, such as isocyanide 1,1-insertion by Ni(II). Here we show a (N-heterocyclic carbene)Ni(II) catalyst that enables cyclopropene-isocyanide [5 + 1] benzannulation. As shown in the broad substrate scope and a [trans-(N-heterocyclic carbene)Ni(isocyanide)Br2] crystal structure, the desired cross-reactivity is cooperatively controlled by the high reactivity of the cyclopropene, the sterically bulky N-heterocyclic carbene, and the strong coordination ability of the isocyanide. This direct addition strategy offers aromatic amine derivatives and complements the Dötz benzannulation and Semmelhack/Wulff 1,4-hydroquinone synthesis. Several sterically bulky, fused, and multi-substituted anilines and unsymmetric functionalized spiro-ring structures are prepared from those easily accessible starting materials expediently.

6.
Angew Chem Int Ed Engl ; 59(13): 5288-5292, 2020 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-31943646

RESUMO

Cross-dimerization of a methylenecyclopropane (1) and an unactivated alkene (2) with typical hydroalkenylation reactivity was observed for the first time by using a [NHC-Ni(allyl)]BArF catalyst (NHC=N-heterocyclic carbene). Results show that the C-C cleavage of 1 did not involve a Ni0 oxidative addition, which was crucial in former systems. Thus the method reported here emerges as a complementary method for attaining highly chemo- and regioselective synthesis of methylenecyclopentanes (3) with broad scope. An efficient NHC/NiII -catalyzed rearrangement of 1 leads to the convergent synthesis of 3 in the presence of 2.

7.
Medicine (Baltimore) ; 98(10): e14566, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30855440

RESUMO

The aim of the present study was to investigate factors affecting ablation effect and safety of ultrasound-guided high-intensity focused ultrasound (USgHIFU) for uterine fibroids (UFs).A retrospective analysis of 346 patients with symptomatic UFs who were treated with USgHIFU was performed. All UFs was grouped based on magnetic resonance imaging (MRI) characteristics before HIFU; all adverse events and treatment data were recorded during and after HIFU. One-way analysis of variance and multiple linear regression analysis were used to evaluate the effect of USgHIFU treatment and affecting factors.The results showed that the mean age of patients was 38.3 ±â€Š6.1 years, with the mean nonperfusion volume rate of 74.4 ±â€Š14.7% and the mean energy efficiency factor (EEF) of 7.2 ±â€Š4.8 J/mm. Except for the size group, the ablation rate was significantly different (P < .001); and the anterior, intramural, hypointense (T2WI), and mild enhancement (T1WI contrast enhancement) UFs had the highest ablation rate. The EEF of the anterior, intramural, hypointense (T2WI), mild enhancement (T1WI contrast enhancement), and >5 cm UFs had minimum value, with a statistically significant difference (P < .01). According to multiple linear regression model, the distance from the UFs ventral side to the skin, enhancement type on T1WI, size of UFs, signal intensity on T2WI, location of UFs, type and volume of fibroids all had a line relationship with EEF, and the enhancement type on T1WI was the greatest factor affecting the ablation effect. Some patients (37.6%) had thermal injury of the sacrum on MRI, but no serious adverse events were observed.Our results suggest that USgHIFU can be safely used and have a promising prospect for treating UFs, even though its effect may be affected by anatomical features, tissue characteristics, and blood supply.


Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade , Leiomioma/diagnóstico por imagem , Leiomioma/terapia , Ultrassonografia de Intervenção , Adulto , Feminino , Ablação por Ultrassom Focalizado de Alta Intensidade/efeitos adversos , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Ultrassonografia de Intervenção/métodos , Útero/diagnóstico por imagem , Adulto Jovem
8.
Angew Chem Int Ed Engl ; 58(17): 5702-5706, 2019 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-30779298

RESUMO

A cross-hydroalkenylation/rearrangement cascade (HARC), using a cyclopropene and alkyne as substrate pairs, was achieved for the first time by using new [(NHC)Ni(allyl)]BArF catalysts (NHC=N-heterocyclic carbenes). By controlling the (NHC)NiII H relative insertion reactivity with cyclopropene and alkyne, a broad scope of cyclopentadienes was obtained with highly selectively. The structural features of the new (NHC)NiII catalyst were important for the success of the reaction. The mild reaction conditions employed may serve as an entry for exploring (NHC)NiII -assisted vinylcyclopropane rearrangement reactivity.

9.
Int J Hyperthermia ; 35(1): 534-540, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30428735

RESUMO

OBJECTIVE: To investigate factors affecting effects of ultrasound guided high intensity focused ultrasound (USgHIFU) in the treatment of single uterine fibroids (UFs) with different magnetic resonance imaging (MRI) features. METHODS: A total of 207 patients with single symptomatic UFs who were treated with HIFU were retrospectively analyzed. All UFs were grouped according to MRI features, and factors affecting HIFU ablation were set as independent variables. Non-perfusion volume ratio (NPVR) and energy efficiency factor (EEF) were set as dependent variables to establish multiple linear regression models with a stepwise method. RESULTS: All patients had successful HIFU treatment, with the mean NPVR of 74.7 ± 15.1% and the mean EEF of 7.4 ± 5.2 j/mm3. The NPVR was negatively correlated with transmural type of UFs, hyperintense on T2 weighted image (T2WI), enhancement type on T1 weighted image (T1WI), distance from UFs ventral side to skin and posterior location of UFs, but positively correlated with anterior location of UFs, hypointense on T2WI and anteverted uterus (uterine location). The EEF was negatively correlated with size, anterior location of UFs and hypointense on T2WI, but positively correlated with distance from UFs ventral side to skin, enhancement type on T1WI and transmural type of UFs. The UFs size and enhancement type on T1WI were the greatest factors affecting the ablation effect. CONCLUSIONS: The effect of HIFU treatment for single UFs is affected by multiple factors, and the UFs of hypointense on T2WI, large size, mild enhancement on T1WI and anteverted uterus can be easily ablated with high ablation efficiency.


Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Leiomioma/cirurgia , Imageamento por Ressonância Magnética/métodos , Adolescente , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
10.
J Bone Oncol ; 12: 69-77, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30094136

RESUMO

PURPOSE: To investigate effects and heat distribution of radiofrequency ablation (RFA) on vertebral tumors in vitro and in vivo swine experiments and its clinical application. MATERIALS AND METHODS: RFA was performed on the swine spine in vitro and in vivo for 20 min at 90 °C at the electrode tip, and the temperature at the electrode tip and surrounding tissues were recorded. Clinical application of ablation combined with vertebroplasty was subsequently performed in 4 patients with spinal tumors. RESULTS: In the in vitro study, the mean temperature at the front and ventral wall of the spinal canal was 50.8 °C and 43.6 °C, respectively, at 20 mm significantly greater than 37.7 °C and 33.7 ± 1.7 °C, respectively, at 10 mm ablation depth. The coagulative necrosis area was significantly (P < 0.0001) greater at 20 mm depth than at 10 mm depth (mean 17.0 × 20.7 mm2 vs. 14.2 × 16.6 mm2). In the in vivo experiment, the local temperature increased significantly (P < 0.05) from around 36 °C before ablation to over 41 °C at 20 min after ablation, with the temperature at the electrode tip (90.4 °C) and within the vertebral body (67.0 °C) significantly (P < 0.05) greater than at the posterior (41.9 °C) and lateral wall (41.8 °C). From 2 to 5 weeks, bone remodeling began. Clinically, all four patients had successful RFA and vertebroplasty, with no neurological deficits. The pain scores were significanlty (P < 0.05) improved before (4.5-10, mean 8.0) compared with at four weeks (0-1.8, mean 1.8). CONCLUSION: The clustered electrode can be efficiently and safely applied in the treatment of spinal tumors without damaging the spinal cord and adjacent nerves by heat distribution.

11.
Jpn J Clin Oncol ; 48(8): 753-759, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29931084

RESUMO

PURPOSE: To investigate the pain relief effect and safety of percutaneous radiofrequency ablation (RFA) with a multitined electrode combined with cement injection in patients with painful metastatic bone tumors. MATERIALS AND METHODS: Sixteen patients with 34 osteolytic metastatic lesions were treated with RFA including 4 males and 12 females (age range 54-84). Thirteen patients with spinal metastases received additional cement injection. Medical imaging, a visual analog scale (VAS) and the EORTC QLQ-C30 were performed to evaluate the metastatic lesion, pain and quality of life, respectively, before and after RFA and at follow-ups. RESULTS: The RFA and/or vertebroplasty with cement injection were successful in all patients (100%). Except for one patient who had cement leakage, no intraprocedural complications occurred. After RFA, severe refractory pain was greatly relieved in all patients, with pretreatment VAS score of 8.1 ± 1.4 significantly reduced to 5.5 ± 1.1 at 24 h, 2.8 ± 0.6 at 1 week and 1.4 ± 0.8 at 6 months (P < 0.01). The EORTC QLQ-C30 scale at 1 month demonstrated significant improvement (P < 0.05) in the physical (P = 0.03) and emotion function (P = 0.003), global health status (P = 0.002), pain (P = 0.001) and insomnia (P = 0.002). The analgesics were reduced after the procedure and stopped 2 months later in all patients, with greatly improved quality of life and no apparent pain. Followed up for 6-12 months, all patients remained alive with no recurrence of pain. Palliative pain relief and safety of percutaneous radiofrequency ablation combined with cement injection for bone metastasis. CONCLUSION: RFA with or without bone cement is safe and effective in the palliative treatment of pain caused by metastatic bone tumors.


Assuntos
Cimentos Ósseos/uso terapêutico , Neoplasias Ósseas/secundário , Neoplasias Ósseas/terapia , Ablação por Cateter/efeitos adversos , Manejo da Dor , Cuidados Paliativos , Adulto , Idoso , Idoso de 80 Anos ou mais , Analgésicos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/tratamento farmacológico , Medição da Dor , Qualidade de Vida , Inquéritos e Questionários
12.
Iran J Allergy Asthma Immunol ; 17(1): 29-38, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29512367

RESUMO

Connexion 43 (Cx43), a gap junction protein, is expressed abundantly in the airway and has been implicated in the pathogenesis of asthma. However, the effects of blocking Cx43 in asthma remain unclear. We investigated the therapeutic effects of two specific Cx43 inhibitors (Gap26 and Gap27) on the development of allergic airway disease in mice. Allergic asthma was induced in BALB/c mice by sensitization and challenge with ovalbumin (OVA). Different doses of Cx43 inhibitors were administered by aerosol inhalation 1 h after OVA challenge on days 21 and 23. Airway hyperresponsiveness (AHR), lung pathology, mucus production, and inflammatory cells and cytokines in bronchoalveolar lavage fluid (BALF) were examined. We found that Gap26 significantly inhibited OVA-induced AHR, inflammatory cell infiltration surrounding the bronchia, mucus production, inflammatory cells and cytokines in BALF, and OVA-specific IgE in the serum in a dose-dependent manner. Gap27 showed effects similar to those of Gap26 in inhibiting inflammatory cytokine production in BALF. We conclude Cx43 inhibitor inhalation alleviates asthma featuresin mice and may be a promising therapy for clinical asthma.


Assuntos
Asma/metabolismo , Conexina 43/antagonistas & inibidores , Inflamação/metabolismo , Peptídeos/administração & dosagem , Hipersensibilidade Respiratória/metabolismo , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Imunoglobulina E/sangue , Mediadores da Inflamação/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Ovalbumina/imunologia , Peptídeos/farmacologia
13.
Org Biomol Chem ; 16(7): 1079-1082, 2018 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-29368785

RESUMO

A highly diastereoselective synthesis of tertiary α-fluoro carbonyl compounds is reported in only two chemical steps from a simple alkyne through the reaction of stereodefined fully substituted silyl ketene hemiaminal derivatives with Selectfluor.

14.
Org Lett ; 19(21): 5932-5935, 2017 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-29043822

RESUMO

A wide range of alkyl-substituted allyl reagents, as well as nonstabilized carbon nucleophiles, was successfully used for the first time in the palladium-catalyzed asymmetric allylic alkylation reaction, affording the corresponding allylic alkylated products in high yields with high enantioselectivities. The usefulness of the protocol has been demonstrated by the enantioselective synthesis of an important chiral building block and enantiomer of Dubiusamine A.

15.
Jpn J Radiol ; 35(1): 31-39, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27822778

RESUMO

PURPOSE: To investigate in vivo effect of radiofrequency ablation (RFA) on swine long bones and the repair process. MATERIALS AND METHODS: RFA was performed in six swine at the end and middle part of the tibia or femur. After RFA, radiological examinations were performed, and the swine were killed immediately and at different time points post-RFA for histopathological examination. RESULTS: All swine had successful RFA. The RFA-induced elliptical necrotic area ranged from 3.81-5.24 cm2 (mean 4.08 ± 0.73 cm2) at the bone end but 5.60-8.98 cm2 (mean 7.58 ± 1.41) at the middle part immediately after RFA until 10 days, with the necrosis area significantly smaller (P = 0.000) at the end than at the middle. RFA only damaged the cortical bone slightly (0.01 cm thick) with no damage to the soft tissues outside the compact bone at both the end and middle. Surrounding the elliptic pale zone of coagulative necrosis was a narrow brown band of hemorrhage and inflammatory exudate. From day 10 until week 12, tissue proliferation and repair became increasingly apparent, with proliferated granulation, fibrous tissue, and fresh and mature bone trabecula. CONCLUSION: RFA can quickly and effectively destroy the cancellous bone tissue without affecting the cortical bone and activate bone remodeling.


Assuntos
Remodelação Óssea/fisiologia , Ablação por Cateter/métodos , Fêmur/cirurgia , Tíbia/cirurgia , Animais , Ablação por Cateter/efeitos adversos , Modelos Animais , Necrose/etiologia , Suínos
16.
J Org Chem ; 79(24): 12010-7, 2014 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-25284365

RESUMO

By consideration of the mechanism of Pd-catalyzed cyclopropanation and allylation, NHC-pyridine compounds were adopted as the ligand in Pd-catalyzed cyclopropanation of esters and monosubstituted allylic reagents. The corresponding cyclopropanes were afforded as major products in moderate to good yields with high cyclopropane/allylation selectivity.


Assuntos
Carbonatos/química , Ciclopropanos/química , Piridinas/química , Catálise , Ésteres , Indicadores e Reagentes/química , Ligantes , Estrutura Molecular , Paládio
17.
J Thorac Dis ; 4(6): 583-7, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23205282

RESUMO

OBJECTIVE: This study investigated the rapid onset of bronchodilation effect and compared lung function changes following budesonide/formoterol (Symbicort Turbuhaler®) inhalation in Chinese patients with moderate-severe chronic obstructive pulmonary disease (COPD) and bronchial asthma. METHODS: In this open-label, parallel-group clinical study, patients eligible for study were divided into COPD group (n=62, mean age 68.16±8.75 years) and asthma group (n=30, mean age 45.80±12.35 years). Lung function tests (include FEV1, FVC, FEV1/FVC, and IC) were performed at baseline (t=0 min time point, value before inhalation of budesonide/formoterol), and then eligible patients received two inhalations of budesonide/formoterol (160/4.5 µg). Lung function tests were reassessed at t=3, 10 and 30 min time point. The primary end-point was lung function change 3 min after drug inhalation, and the secondary end-points were comparison of the gas flow rate (ΔFEV1) and volume responses (ΔFVC, ΔIC) between COPD and asthma patients after inhalation of budesonide/formoterol. RESULTS: Compared with the baseline, all patients significantly improved their lung function (included FEV1, FVC, FEV1/FVC, and IC) at 3 min (P<0.05). Greater bronchodilation efficacy was found in the asthma group compared with the COPD group (P<0.05). In the asthmatic patients, the curves of FEV1, FVC, FEV1/FVC, IC, showed improvement with an ascending trend at all time points from 3 to 30 min. Whereas in the COPD patients, only the curves of FEV1, FVC, IC showed similar pattern. We found that ΔFVC was significantly higher than ΔFEV1 in both groups (P<0.05), but no significant difference between ΔIC and ΔFEV1 (P>0.05). Compared with COPD group, asthma group had higher level of ΔFEV1 and ΔIC (P<0.05), but no significant difference for ΔFVC can be found. CONCLUSIONS: Budesonide/formoterol has a fast onset of bronchodilation effect in patients with moderate-severe COPD and asthma. Greater efficacy was found in the asthma group compared with the COPD group. The gas flow rate and volume responses in patients with COPD differ from those with asthma after inhalation of Budesonide/formoterol.

18.
J Org Chem ; 77(20): 8980-5, 2012 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-22992268

RESUMO

The Pd-catalyzed asymmetric allylic alkylation (AAA) reaction of nitromethane with monosubstituted allyl substrates was realized for the first time to provide corresponding products in high yields with excellent regio- and enantioselectivities. The protocol was applied to the enantioselective synthesis of (R)-baclofen and (R)-rolipram.


Assuntos
Compostos Alílicos/química , Baclofeno/síntese química , Metano/análogos & derivados , Nitroparafinas/química , Compostos Organometálicos/química , Paládio/química , Rolipram/síntese química , Alquilação , Baclofeno/química , Catálise , Metano/química , Estrutura Molecular , Rolipram/química , Estereoisomerismo
19.
Chin Med J (Engl) ; 125(5): 957-60, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22490606

RESUMO

A 90-year-old Chinese man was transferred to the Emergency Department of the Affiliated Shantou Hospital of Sun Yat-sen University for treatment of an acute myocardial infarction. He suffered chest pain with three days of cough, dyspnea and fever. A diagnosis of Takotsubo cardiomyopathy was made in normal coronary arteries from urgent coronary angiography and characteristic apical dyskinesis and basal hyper contractility in left ventriculography. The patient died from severe multi-organ failure on the second day of hospitalization.


Assuntos
Cardiomiopatia de Takotsubo/diagnóstico , Idoso de 80 Anos ou mais , Angiografia Coronária , Evolução Fatal , Humanos , Masculino , Cardiomiopatia de Takotsubo/diagnóstico por imagem
20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(11): 3146-50, 2012 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-23387197

RESUMO

Presented is a compact instrument developed for in situ high-stable and sensitive continuous measurement of trace gases in air, with results shown for ambient methane (CH4) concentration accurate, real-time and in-situ. This instrument takes advantage of recent technology in thermoelectrically cooling (TEC) pulsed Fabry-Perot (FP) quantum cascaded laser (QCL) driving in a pulse mode operating at 7.5 microm ambient temperature to cover a fundamental spectral absorption band near v4 of CH4. A high quality Liquid Nitrogen (LN) cooled Mercury Cadmium Telluride (HgCdTe) mid-infrared (MIR) detector is used along with a total reflection coated gold ellipsoid mirror offering 20 cm single pass optical absorption in an open-path cell to achieve stability of 5.2 x 10(-3) under experimental condition of 200 micromol x mol(-1) measured ambient CH4. The instrument integrated software via time discriminating electronics technology to control QCL provides continuous quantitative trace gas measurements without calibration. The results show that the instrument can be applied to field measurements of gases of environmental concern. Additional, operator could substitute a QCL operating at a different wavelength to measure other gases.

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