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1.
Zhonghua Yi Xue Za Zhi ; 104(34): 3221-3227, 2024 Sep 03.
Artigo em Chinês | MEDLINE | ID: mdl-39193607

RESUMO

Objective: To compare the safety and short-term efficacy of robotic-assisted thoracic surgery(RATS) and video-assisted thoracoscopic surgery(VATS) in patients with non-small cell lung cancer (NSCLC). Methods: A retrospective analysis of the clinical data of 2 058 NSCLC patients who underwent RATS and VATS from January 2021 to December 2022 in Xiangya Hospital of Central South University was conducted, including 1 006 males and 1 052 females, with the age of (57.3±9.9) years. According to the surgical approach, the patients were divided into RATS group (n=1 190) and VATS group (n=868). The nearest neighbor matching method was used to perform 1∶1 propensity score matching (PSM). A comparison was made about the intraoperative conditions and postoperative complication rates between the RATS and VATS groups before and after PSM. Furthermore, after PSM, a stratified analysis was conducted based on surgical approach, separately comparing the intraoperative conditions and postoperative complication rates between the VATS and RATS groups among patients who underwent lobectomy and segmentectomy, respectively. Results: After PSM, a total of 1 692 patients were included, with 846 patients in both the VATS and RATS groups. After stratification based on surgical approach, there were 503 patients in the RATS group and 548 patients in the VATS group for lobectomy, and 338 patients in the RATS group and 298 patients in the VATS group for segmentectomy. Before PSM, statistically significant differences were observed between the RATS and VATS groups in terms of intraoperative conversion to open thoracotomy, number of lymph node dissection/sampling stations, extubation time, total length of hospital stay, and total hospitalization costs (all P<0.001). After PSM, compared with the VATS group, the RATS group had a lower intraoperative conversion rate to open surgery [1.2% (10/846) vs 5.1% (43/846)], less intraoperative blood loss [(73.6±77.4) ml vs (112.6±239.3) ml], a greater number of sampled/dissected lymph node stations [(4.8±2.0) vs (3.7±1.8)], a shorter duration of drainage tube placement [(3.6±2.7) d vs (4.1±2.5) d], and a higher postoperative drainage volume [(273.9±183.0) ml vs (256.5±168.7) ml] (all P<0.001). There was no statistically significant difference in the incidence of postoperative complications between the two groups (P=0.108). The results of the surgical stratification analysis showed statistically significant differences between the two groups in terms of intraoperative blood loss, number of lymph node dissection/sampling stations, extubation time, and total hospitalization costs for both lobectomy and segmentectomy surgeries (all P<0.001). In lobectomy surgeries, the RATS group had a lower rate of intraoperative conversion to open thoracotomy than that of VATS group [1.6% (8/503) vs 7.7% (42/548), P<0.001]. In segmentectomy surgeries, the RATS group had more postoperative drainage volume than that of VATS group [(249.8±151.5) ml vs (218.7±132.9) ml, P=0.023]. There was no statistically significant difference in the incidence of surgical complications between the two groups for both lobectomy and segmentectomy surgeries (both P>0.05). Conclusion: In the surgical management of NSCLC, RATS offers more advantages over VATS in reducing conversion rates to open surgery, minimizing perioperative adverse events, and facilitating faster patient recovery postoperatively.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Pneumonectomia , Complicações Pós-Operatórias , Procedimentos Cirúrgicos Robóticos , Cirurgia Torácica Vídeoassistida , Masculino , Neoplasias Pulmonares/cirurgia , Humanos , Carcinoma Pulmonar de Células não Pequenas/cirurgia , Pessoa de Meia-Idade , Feminino , Cirurgia Torácica Vídeoassistida/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Estudos Retrospectivos , Pneumonectomia/métodos , Resultado do Tratamento , Pontuação de Propensão
2.
Phys Rev Lett ; 133(6): 061001, 2024 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-39178452

RESUMO

In this Letter we try to search for signals generated by ultraheavy dark matter at the Large High Altitude Air Shower Observatory (LHAASO) data. We look for possible γ rays by dark matter annihilation or decay from 16 dwarf spheroidal galaxies in the field of view of the LHAASO. Dwarf spheroidal galaxies are among the most promising targets for indirect detection of dark matter that have low fluxes of astrophysical γ-ray background while having large amount of dark matter. By analyzing more than 700 days of observational data at LHAASO, no significant dark matter signal from 1 TeV to 1 EeV is detected. Accordingly we derive the most stringent constraints on the ultraheavy dark matter annihilation cross section up to EeV. The constraints on the lifetime of dark matter in decay mode are also derived.

4.
Phys Rev Lett ; 133(7): 071501, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39213544

RESUMO

On 9 October 2022, the Large High Altitude Air Shower Observatory (LHAASO) reported the observation of the very early TeV afterglow of the brightest-of-all-time gamma-ray burst 221009A, recording the highest photon statistics in the TeV band ever obtained from a gamma-ray burst. We use this unique observation to place stringent constraints on the energy dependence of the speed of light in vacuum, a manifestation of Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that the 95% confidence level lower limits on the QG energy scales are E_{QG,1}>10 times the Planck energy E_{Pl} for the linear LIV effect, and E_{QG,2}>6×10^{-8}E_{Pl} for the quadratic LIV effect. Our limits on the quadratic LIV case improve previous best bounds by factors of 5-7.

5.
Phys Rev Lett ; 132(13): 131002, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38613275

RESUMO

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

6.
Phys Rev Lett ; 131(15): 151001, 2023 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-37897763

RESUMO

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10 TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60 TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

7.
Science ; 380(6652): 1390-1396, 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37289911

RESUMO

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory (LHAASO) of the bright GRB 221009A, which serendipitously occurred within the instrument's field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger and then rose to a peak ~10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle of ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

8.
Zhonghua Yi Xue Za Zhi ; 102(39): 3127-3133, 2022 Oct 25.
Artigo em Chinês | MEDLINE | ID: mdl-36274597

RESUMO

Objective: To evaluate the safety and feasibility of robotic-assisted thoracoscopic day surgery for pulmonary nodules. Methods: Clinical data of 523 patients with pulmonary nodule underwent robotic-assisted thoracoscopic surgery in the Department of Thoracic Surgery, Xiangya Hospital, Central South University from January 2021 to June 2022 were retrospectively analyzed, which including 223 males and 300 females, aged from 19 to 72 (54.0±11.7) years. Those patients were divided into the day surgery group (DSG) and inpatient surgery group (ISG) according to perioperative management methods. Propensity score matching (PSM) (1∶2) was performed according to the general baseline information, T stage of the tumor, surgery approach, and tumor position, and a total of 178 patients were finally included. Clinical outcomes of DSG were observed. The differences in incidence of postoperative complications, treatment-related costs and resource consumption between DSG and ISG were compared. Subgroup analysis was performed according to surgery method to evaluate the difference between DSG and ISG in lobectomy and sublobectomy. Results: In 81 cases DSG, eight patients were transferred to thoracic surgery ward, and the day surgery discharge rate was 90% (73/81). There was no statistically significant difference in incidence of postoperative complications between DSG and ISG (P=0.612). The length of stay after surgery, period of chest draining, average hospital cost, and drug cost of DSG were statistically significant lower than ISG, ((2.19±0.84) vs (4.74±1.81) days, (1.70±0.65) vs (3.45±1.85) days, (6.64±0.74) vs (8.29±0.97)×104 CNY, (0.35±0.07) vs (0.69±0.18)×104 CNY), respectively(all P<0.05). The drainage volume and VAS score at discharge in DSG and ISG group were(220.47±120.02) ml and(242.21±129.96) ml, 1.68±0.79 and 1.64±0.91, respectively, with no statistically significant difference (P>0.05). In subgroup analysis, there was no statistically significant difference in incidence of postoperative complications, drainage volume after surgery and VAS score at discharge between DSG and ISG both for lobectomy and sublobectomy patients. And the results of the length of stay after surgery, period of chest draining, and drug cost in DSG were also significantly lower than ISG (P<0.05). Conclusions: Robotic-assisted thoracoscopic day surgery for pulmonary nodule is safe and feasible, with the advantage of short length of stay after surgery, short period of chest draining, less average hospital cost and drug cost. There is no difference in incidence of postoperative complications between DSG and ISG.


Assuntos
Neoplasias Pulmonares , Nódulos Pulmonares Múltiplos , Procedimentos Cirúrgicos Robóticos , Masculino , Feminino , Humanos , Estudos Retrospectivos , Cirurgia Torácica Vídeoassistida/efeitos adversos , Cirurgia Torácica Vídeoassistida/métodos , Pontuação de Propensão , Estudos de Viabilidade , Procedimentos Cirúrgicos Ambulatórios , Tempo de Internação , Nódulos Pulmonares Múltiplos/etiologia , Nódulos Pulmonares Múltiplos/cirurgia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Neoplasias Pulmonares/cirurgia , Neoplasias Pulmonares/patologia , Pneumonectomia/efeitos adversos
9.
Phys Rev Lett ; 128(5): 051102, 2022 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-35179919

RESUMO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

10.
Phys Rev Lett ; 129(26): 261103, 2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36608208

RESUMO

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9} GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

11.
Phys Rev Lett ; 126(24): 241103, 2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34213924

RESUMO

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25 TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160 TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

12.
Science ; 373(6553): 425-430, 2021 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-34261813

RESUMO

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 1036 ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

13.
Nature ; 594(7861): 33-36, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34002091

RESUMO

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

14.
J Biol Regul Homeost Agents ; 34(1)2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32048500

RESUMO

Notch signaling plays a critical role in the development and function of macrophages. The aim of the present study was to investigate the relationship between Notch signaling pathway and macrophage apoptosis after LPS stimulation. In RAW 264.7 cells, the mRNA expression of Jagged1, Hes1, Hes 5 and GM-CSF, and protein expression of NICD1 and GM-CSF were increased after LPS stimulation. Inhibition of Notch signaling by γ-secretase inhibitor DAPT and the suppression of Notch1 expression using siRNA both significantly prevented LPS induced activation of JNK and NF-kB, and simultaneously the expression of GM-CSF was also down regulated significantly. JNK inhibitor SP600125 was used to block the phosphorylation of JNK signaling, Western blot results showed that the activation of NF-kB was blocked and expression of GM-CSF was down-regulated. Finally, flow cytometry analyses showed that the Notch signaling was involved in the regulation of macrophage apoptosis after LPS stimulation. Our study showed that the Notch signaling pathway was activated and involved in the regulation of macrophage apoptosis after LPS stimulation through JNK/ NF-kB signaling regulated GM-CSF expression.

15.
Eur J Surg Oncol ; 38(12): 1149-55, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22901959

RESUMO

AIMS: The standard surgical procedure for elderly (≥ 70 years) patients with clinical stage I non-small cell lung cancer (NSCLC) was investigated. METHODS: A non-randomized prospective controlled study was conducted to compare lobectomy with segmental resection for the treatment of elderly clinical stage I lung cancer patients under different pulmonary function. Perioperative indicators including time and volume of thoracic drainage, incidence of postoperative complications, locoregional recurrence rates, and 1, 3, and 5-year survival rates were analyzed. RESULTS: A total of 184 patients were included in the study. Patients were classified into two groups according to pulmonary function: group 1 included 64 patients who had poor pulmonary function, with a forced expiratory volume in 1 s (FEV(1)) of less than 1.5 L, whereas group 2 consisted of 120 patients with an FEV(1) ≥ 1.5 L. The patients in group 1 had a longer postoperative mechanical ventilation time and a higher incidence rate of respiratory associated complications than those in group 2 (21.9 vs. 8.35%, p = 0.009). The local recurrence and long-term survival rates were not significantly different between lobectomy and segmental resection. Among the patients who underwent segmental resection, those who had regional lymph node dissection showed a higher 3-year and 5-year survival rate than those undergoing selected lymph node resection (77.8 vs. 51.7%, p = 0.042; 55.6 vs. 27.6%, p = 0.034), but this was not significant in lobectomy. CONCLUSIONS: Segmental resection combined with regional lymph node resection could be the best choice for elderly clinical stage I NSCLC patients with FEV(1) < 1.5 L.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/cirurgia , Neoplasias Pulmonares/cirurgia , Estadiamento de Neoplasias , Pneumonectomia/métodos , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Carcinoma Pulmonar de Células não Pequenas/diagnóstico , Feminino , Seguimentos , Humanos , Incidência , Neoplasias Pulmonares/diagnóstico , Masculino , Recidiva Local de Neoplasia/epidemiologia , Complicações Pós-Operatórias/epidemiologia , Estudos Prospectivos , Fatores de Risco , Resultado do Tratamento
16.
Chang Gung Med J ; 24(9): 541-6, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11725623

RESUMO

BACKGROUND: Fourier-transform infrared spectroscopy (FT-IR) is a powerful tool for study of the secondary conformation of intact protein in biological tissues and for diagnosis of disease states. The purpose of this study is to utilize FT-IR as a diagnostic tool to estimate the secondary structure of amide I in normal and cancer tissue of human colon. METHODS: Pairs of tissue samples from colon cancer and histologically normal mucosa tissue 5-10 cm from the tumor were obtained from a patient who underwent partial colectomy. In the present study we investigated the changes in the secondary structure of amide I of normal and malignant human colon tissue using FT-IR microspectroscopy with attenuated total reflectance. Secondary-derivative analysis relative to the original and curve-fitting analysis infrared spectra were also carried out. RESULTS: The conformational changes of the secondary structure of protein in normal and cancerous human colon tissue were (1) the composition of alpha-helixes increased in human cancerous colon tissue (15.30%) compared to normal colon tissue (11.72%); (2) beta-sheets which were 46.8% in healthy tissue decreased to 30.71% in cancer tissue; (3) beta-turns increased from 26.28% in normal tissue to 38.48% in cancer tissue; and (4) the composition of random coils was not significantly different between normal tissue (15.12%) and cancer tissue (15.51%). CONCLUSION: Our data demonstrate that protein in colon cancer displays abnormal FT-IR spectra. The conformational changes of the secondary structure of this protein in terms of alpha-helixes, beta-sheets and beta-turns were observed in normal and cancerous tissue from the same individual were compared.


Assuntos
Neoplasias do Colo/química , Proteínas de Neoplasias/química , Estrutura Secundária de Proteína , Idoso , Amidas/química , Feminino , Humanos , Conformação Proteica , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Ecotoxicology ; 10(2): 71-7, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11280970

RESUMO

The purpose of this study is to examine the applicability of an infared spectroscopic methodology for the study of an environmental problem. The effect of cyanide concentrations on the biophysical conformation of the fish liver homogenate was determined by using an attenuated total reflectance (ATR)/Fourier transform infrared (FT-IR) microspectroscopy. Alive male model fish, Tilapia Zillii, was used. The liver from fish was isolated and homogenized in pH 8.0 Tris buffer solution. The results indicate that the IR peak intensity increased markedly in the C-H stretching range (3000-2800 cm-1), ester C = O stretching of lipids (1743 cm-1) and carbohydrate bands (1195-950 cm-1), but decreased in the amide I at 1649 cm-1 and the free asymmetric stretching band of phosphate at 1261 cm-1 with the increase of KCN concentrations. The marked release of hepatic enzymes and glutathione into homogenate induced by cyanide might account for the higher IR spectral peak intensity of fish liver tissue after treatment with KCN. The cyanide was also found to induce the protein structure of fish liver homogenate from alpha-helical conformation to beta-conformation.


Assuntos
Cianeto de Hidrogênio/efeitos adversos , Fígado/patologia , Tilápia , Poluentes da Água/efeitos adversos , Animais , Fenômenos Biofísicos , Biofísica , Masculino , Espectroscopia de Infravermelho com Transformada de Fourier
18.
Ultrastruct Pathol ; 25(5): 357-60, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11758716

RESUMO

A highly efficient Fourier transform infrared (FT-IR) microscopy was used to determine the biophysical structure of anagen scalp hair roots of neonates suffering from congenital hypothyroidism (CH) due to ectopic thyroid. The present results indicate that the lower composition near 1,053 cm(-1) (also assigned to the aromatic iodide stretching band) in the infrared (IR) spectra of the hair roots for CH patients was directly associated with the lower serum level of T4 and fT4, and the elevated TSH levels determined by RIA method. This strongly implies the lower evidence of the aromatic iodide stretching band in the IR spectra of hair roots. These findings suggest that FT-IR microscopy has the potential to become a good diagnostic tool and that hair can be useful as a genetic marker.


Assuntos
Hipotireoidismo Congênito , Cabelo/patologia , Hipotireoidismo/diagnóstico , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Ciclo Celular , Feminino , Humanos , Hipotireoidismo/sangue , Recém-Nascido , Masculino , Microespectrofotometria/métodos , Couro Cabeludo , Hormônios Tireóideos/sangue
19.
Food Addit Contam ; 17(10): 821-7, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11103265

RESUMO

The solid-state stability of aspartame hemihydrate (APM) sweetener during thermal treatment is important information for the food industry. The present study uses the novel technique of Fourier transform infrared microspectroscopy equipped with differential scanning calorimetry (FT-IR/DSC microscopic system) to accelerate and determine simultaneously the thermal-dependent impurity formation of solid-state APM. The results indicate a dramatic change in IR spectra from 50, 110 or 153 degrees C, which was respectively attributed to the onset temperature of water evaporation, dehydration and cyclization processes. It is suggested that the processes of dehydration and intramolecular cyclization occurred in the solid-state APM during the heating process. As an impurity, 3-carboxymethyl-6-benzyl-2,5-diketopiperazine (DKP) degraded from solid state APM via intramolecular cyclization and liberation of methanol. This was evidenced by this novel FT-IR/DSC microscopic system in a one-step procedure.


Assuntos
Aspartame/química , Piperazinas/análise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Aspartame/análise , Varredura Diferencial de Calorimetria/métodos , Ciclização , Dessecação , Estabilidade de Medicamentos , Temperatura
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