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1.
Opt Lett ; 48(1): 9-12, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36563357

RESUMO

In this work, we experimentally perform time delay interferometry by using a transfer oscillator, which is capable of reducing the laser frequency noise and the clock noise simultaneously in the post processing. The iodine frequency reference is coherently downconverted to the microwave frequency using a laser frequency comb. The residual noise of the downconversion network is 5 × 10-6Hz/Hz1/2 at 0.7 mHz, and 4 × 10-6Hz/Hz1/2 at 0.1 Hz, indicating high homology between the optical frequency and the microwave frequency. We carry out time delay interferometry with the aid of the electrical delay module, which can introduce large time delays. The results show that the laser frequency noise and the clock noise can be reduced simultaneously by ten and three orders of magnitude, respectively, in the frequency band from 0.1 mHz to 0.1 Hz. The performance of the noise reduction can reach 6 × 10-8Hz/Hz1/2 at 0.1 mHz, and 7 × 10-7Hz/Hz1/2 at 1 mHz, meeting the requirements of the space-borne gravitational wave detection. Our work will be able to offer an alternative method for the frequency comb-based time delay interferometry in the future space-borne gravitational wave detectors.

2.
J Asian Nat Prod Res ; 25(10): 999-1011, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36899456

RESUMO

Osthole is the prominent active ingredient isolated from Cnidium. The role of osthole in chronic obstructive pulmonary disease (COPD) was investigated herein. Bronchial epithelial 16HBE cells were exposed to cigarette smoke extract (CSE) to generate injury models. The concentration of CSE had an inverse correlation with cell viability. Osthole suppressed inflammation, oxidative stress, apoptosis, and pyroptosis in 16HBE cells, along with a decrease in RIPK2 level. RIPK2 overexpression reversed the effects of osthole on the abovementioned aspects. This study found that the osthole could reduce RIPK2 level, inhibit pyroptosis, and alleviate the damage in 16HBE cells under CSE stimulation.


Assuntos
Cnidium , Piroptose , Linhagem Celular , Apoptose , Nicotiana , Células Epiteliais
3.
Eur Radiol ; 30(3): 1426-1435, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31776739

RESUMO

PURPOSE: To investigate the clinical value of real-time three-dimensional contrast-enhanced ultrasound (3D-CEUS) in the detection of sentinel lymph nodes (SLNs) and drainage lymphatics in breast cancer patients. METHOD: The prospective study was performed in women with pathology-confirmed T1/2 breast cancer between June 2016 and December 2017 who underwent sentinel lymph node biopsy and 3D-CEUS. The number, size, location, enhancement pattern of SLNs, and the lymphatic drainage patterns were reviewed. The routes, location of SLNs, and lymph channels (LCs) on the surface were marked. All patients underwent blue dye-guided sentinel lymph node biopsy (SLNB) finally. RESULTS: According to the postoperative pathology findings and the blue dye staining of the lymphatic drainage routes, there are six patterns of lymphatic drainage routes and the coincidence rate of the 3D-CEUS was 97.4%; the sensitivity, specificity, positive predictive value, negative predictive value, the LN detection rate, and the correct diagnosis rate of the 3D-CEUS were 75%, 93.0%, 81.8%, 89.9%, 95.3%, and 87.7%, respectively. CONCLUSION: 3D-CEUS is a new feasible and useful approach to detect the SLNs and LCs. 3D-CEUS can accurately localize the LCs and SLNs and estimate the presence of metastatic lymph nodes. KEY POINTS: • The three-dimensional contrast-enhanced ultrasound can detect the sentinel lymph nodes. • The three-dimensional contrast-enhanced ultrasound can show the stereo direction of sentinel lymph nodes and lymph drainage routes. • The three-dimensional contrast-enhanced ultrasound can accurately localize the LCs and SLNs and estimate the presence of metastatic lymph nodes.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Carcinoma Ductal de Mama/diagnóstico por imagem , Carcinoma Lobular/diagnóstico por imagem , Imageamento Tridimensional/métodos , Vasos Linfáticos/diagnóstico por imagem , Linfonodo Sentinela/diagnóstico por imagem , Ultrassonografia/métodos , Adulto , Idoso , Neoplasias da Mama/patologia , Neoplasias da Mama/cirurgia , Carcinoma Ductal de Mama/patologia , Carcinoma Ductal de Mama/cirurgia , Carcinoma Lobular/patologia , Carcinoma Lobular/cirurgia , Meios de Contraste , Feminino , Humanos , Linfonodos/diagnóstico por imagem , Linfonodos/patologia , Vasos Linfáticos/patologia , Pessoa de Meia-Idade , Estudos Prospectivos , Sensibilidade e Especificidade , Linfonodo Sentinela/patologia , Biópsia de Linfonodo Sentinela/métodos
4.
Analyst ; 145(13): 4671-4679, 2020 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32458862

RESUMO

Genotyping of the epidermal growth factor receptor (EGFR) mutation status is of great importance in the screening of appropriate patients with advanced non-small cell lung carcinoma (NSCLC) to receive superior tyrosine kinase inhibitor (TKIs) therapy. Yet conventional assays are generally costly with a relatively long turnaround time for obtaining results, which can lead to a bottleneck for immediately starting TKI therapy in late-staged patients. In this study, we propose an on-site electrochemical platform for sensitive simultaneous genotyping of the two major EGFR mutations (19del and L858R) through plasma ctDNA based on tetrahedral DNA nanostructure decorated screen-printed electrodes (SPE). Linear-after-the-exponential (LATE)-PCR combined with the amplification refractory mutation system (ARMS) was adopted to produce abundant biotin-labeled single-stranded DNA with high amplification efficiency and specificity. Disposable SPE decorated with self-assembled tetrahedral nanostructured DNA probes that showed ordered orientation and good target accessibility enabled the highly efficient hybridization of the specific amplicons through a sandwich-type and quantitatively translated the interfacial hybridization event into electrochemical signals via enzymatic amplification. Taking advantage of the ARMS-based LATE-PCR and the tetrahedral nanostructure-decorated SPE platform, we achieved the accurate detection of around 30 pg DNA of 19del or L858R, or as low as 0.1% of them in the presence of wild-type DNA. Moreover, the EGFR mutation profiles of 13 NSCLC patients we enlisted were accurately genotyped by our electrochemical platform, the results of which were in good agreement with those of commercial genetic detection methods.


Assuntos
DNA Tumoral Circulante/sangue , DNA/química , Técnicas Eletroquímicas/métodos , Receptores ErbB/genética , Técnicas de Genotipagem/métodos , Nanoestruturas/química , Idoso , Carcinoma Pulmonar de Células não Pequenas/genética , Linhagem Celular Tumoral , DNA Tumoral Circulante/genética , Feminino , Humanos , Neoplasias Pulmonares/genética , Masculino , Pessoa de Meia-Idade , Mutação , Conformação de Ácido Nucleico , Reação em Cadeia da Polimerase
5.
J Phys Chem A ; 124(18): 3672-3678, 2020 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-32286070

RESUMO

It is well known that imidazoles, possessing two or more nitro substituents, are potential candidates for highly energetic explosives with detonation parameters comparable to those of 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane. 4,4',5,5'-Tetranitro-2,2'-bi-imidazole (TNBI) is a typical imidazole explosive with energy equivalent to that of RDX but suffers from low sensitivity (impact sensitivity 7 J). 1,1'-Diamino-4,4',5,5'-tetranitro-2,2'-biimidazole (DATNBI), a derivative of TNBI, possesses two -NH2 groups and has a higher detonation velocity (9063 m s-1) and lower impact sensitivity of 15 J, which indicates great potential for future applications. Examination of the thermal decomposition mechanism and kinetics of TNBI and DATNBI gives a more comprehensive view of the influence that the -NH2 group has on the sensitivity and storage safety of the energetic explosive-based TNBI molecular skeleton. Herein, the thermal decomposition mechanism is studied, showing that detachment of -NH2 groups from DATNBI generates 1-diamino-4,4',5,5'-tetranitro-2,2'-biimidazole (ATNBI) and TNBI and induces self-decomposition. Although the decomposition peak temperature of DATNBI is significantly lower than that of TNBI at the same heating rate; its self-accelerating decomposition temperature (50 kg) is only 4 K lower. Therefore, the -NH2 group displays good ability of reducing sensitivity but has no influence on storage safety of DATNBI.

6.
Chemistry ; 23(8): 1901-1909, 2017 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-27870467

RESUMO

We have synthesized a series of new ß-iminoenolates and their corresponding difluoroboron complexes without any traditional gelation moieties, and some of them were able to gelatinize organic solvents. It was found that the presence of halogen atoms as substituents had a significant effect on gelation ability. In particular, bromo-containing compounds 4 A and 4 B exhibited excellent gelation abilities compared with other halogen-substituted gelators. By analyses of the single-crystal structure, the PXRD pattern of the xerogel, and electronic spectral changes during gelation, we deemed that π-π, C-H⋅⋅⋅F, and C-H⋅⋅⋅Br interactions were the driving forces for the gelation of 4 B. Interestingly, (Z)-1-(4-bromophenyl)-2-(3-methylpyrazin-2-yl)ethen-1-ol (8 A), prepared in this work, is the lowest-molecular-weight organogelator to have been reported. It should be noted that although ß-iminoenolates 3 A-5 A are nonemissive in solution, they emit strong yellow light in organogels, which suggests aggregation-induced emissive activity, whereas the difluoroboron complexes 3 B-5 B show strong fluorescence in solutions, organogels, and xerogel-based films. Moreover, we found that the emission of 4 B in a nanofiber-based film could be quenched significantly upon exposure to gaseous trifluoroacetic acid and that the decay time and detection limit were 0.5 s and 0.17 ppm, respectively. Thus, through this work we have provided a new strategy for the design of nontraditional π gelators by introducing halogen atoms into π-conjugated systems with moderate polarities.

7.
Chemistry ; 21(48): 17508-15, 2015 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-26449736

RESUMO

An L-phenylalanine derivative (C12PhBPCP) consisting of a strong emission fluorophore with benzoxazole and cyano groups is designed and synthesized to realize dual responses to volatile acid and organic amine vapors. The photophysical properties and self-assembly of the said derivative in the gel phase are also studied. C12PhBPCP can gelate organic solvents and self-assemble into 1 D nanofibers in the gels. UV/Vis absorption spectral results show H-aggregate formation during gelation, which indicates strong exciton coupling between fluorophores. Both wet gel and xerogel emit strong green fluorescence because the cyano group suppresses fluorescence quenching in the self-assemblies. Moreover, the xerogel film with strong green fluorescence can be used as a dual chemosensor for quantitative detection of volatile acid and organic amine vapors with fast response times and low detection limits owing to its large surface area and amplified fluorescence quenching. The detection limits are 796 ppt and 25 ppb for gaseous aniline and trifluoroacetic acid (TFA), respectively.


Assuntos
Aminas/química , Corantes Fluorescentes/química , Compostos de Anilina/química , Fluorescência , Gases , Géis , Limite de Detecção , Nanofibras , Compostos Orgânicos/química , Fenilalanina/análogos & derivados , Fenilalanina/química , Solventes
8.
Chemistry ; 21(12): 4712-20, 2015 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-25393379

RESUMO

Two L-phenylalanine derivatives with 5,8-bis(2-(carbazol-3-yl)vinyl)quinoxaline (PCQ) and 5,8-bis[2-(carbazol-3-yl)]-2,3-dimethylquinoxaline (DCQ) as fluorophores were synthesized, and their photophysical properties were measured and compared. The two compounds were found to gelate some organic solvents and self-assemble into 1D nanofibers in gels. The wet gel of PCQ emitted a weak orange fluorescence, but the DCQ gel had a strong green one. This result can be due to the presence of two methyl groups and the nonplanar conformation of fluorophore in DCQ. The gel film of DCQ also showed significantly stronger fluorescence than that of PCQ. Thus, the wet gel and xerogel film of DCQ were selected to study their sensing properties to acids. The yellow wet gel of DCQ transformed into a brown sol upon the addition of 0.2 equiv trifluoroacetic acid (TFA), accompanied by emission quenching. The xerogel film of DCQ rapidly responded to volatile acids, such as TFA, HCl, and HOAc. The fluorescence of the xerogel film was gradually quenched with increased concentration of volatile acid vapors. The fibrous film exhibited low detection limits for volatile acid. The detection limits of the thin films for TFA, HCl, and HOAc reached 43, 122, and 950 ppb, respectively.

9.
Chemistry ; 20(47): 15339-43, 2014 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-25314635

RESUMO

A novel method for the synthesis of non-natural L- and D-amino acids by a Ni-catalyzed reductive cross-coupling reaction is described. This strategy enables the racemization-free cross-coupling of serine/homoserine- derived iodides with aryl/acyl/alkyl halides. It provides convenient access to varieties of enantiopure and functionalized amino acids, which are important building blocks in bioactive compounds and pharmaceuticals.


Assuntos
Aminoácidos/química , Níquel/química , Aminoácidos/síntese química , Catálise , Cristalografia por Raios X , Halogênios/química , Conformação Molecular , Acoplamento Oxidativo , Estereoisomerismo
10.
Chemistry ; 20(47): 15334-8, 2014 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-25308802

RESUMO

A copper-catalyzed reductive cross-coupling reaction of nonactivated alkyl tosylates and mesylates with alkyl and aryl bromides was developed. It provides a practical method for efficient and cost-effective construction of aryl-alkyl and alkyl-alkyl CC bonds with stereocontrol from readily available substrates. When used in an intramolecular fashion, the reaction enables convenient access to various substituted carbo- or heterocycles, such as 2,3-dihydrobenzofuran and benzochromene derivatives.

11.
Org Biomol Chem ; 12(32): 6134-44, 2014 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-25008371

RESUMO

New indolocarbazole derivatives emitting strong blue light have been synthesized. It is found that the strong π­π interactions between indolocarbazoles 4­6 without long carbon chains lead to the formation of crystal or crystal-like aggregates. We have previously found that tert-butyl could tune the strength of π­π interactions between carbazole units and the organogels were obtained from tert-butyl substituted carbazoles directed by balanced π­π interactions. Herein, hexadecyl groups were introduced into N-positions of indolocarbazoles in order to reduce the strength of π­π interactions between indolocarbazoles, and compounds 7­9 were prepared. It is interesting that compounds 8 and 9 could form stable organogels in alcohols, acetone, DMSO, and so on, upon ultrasound stimulation. Combined with the results of electronic spectra, XRD patterns and the optimized molecular length based on the semiempirical (AM1) calculations, we suggested the molecular packing modes in gel states, in which the lamellar structures were involved. Although the fluorescence emission of indolocarbazoles 8 and 9 decreased during the gel formation to some extent, the obtained gel nanofibers still emitted strong blue light and the fluorescence emission of the film based on xerogel 9 decreased significantly upon exposure to gaseous TNT. It meant that the xerogels based on indolocarbazoles could be used as fluorescent sensors for detecting vapors of explosives.

12.
Quant Imaging Med Surg ; 14(7): 4804-4814, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-39022279

RESUMO

Background: Capsule-preserving hydrodilatation is a common treatment for adhesive capsulitis (AC), and ultrasound (US) has recently become the most popular adjuvant tool for image-guided glenohumeral joint injection. However, traditional US is hardly adequate to assess extracapsular fluid leakage, which may decide the treatment outcomes. In this study, we explored the value of contrast-enhanced ultrasound (CEUS) guided capsule-preserving hydrodilatation with steroids and ultrasonic contrast agents for treatment of AC. Methods: A total of 40 consecutive patients with AC were prospectively enrolled and received CEUS-guided capsule-preserving hydrodilatation. The number of injection attempts, injection volume, and fluid leakage were recorded, and the correlations with clinical features were analyzed by Pearson or Spearman correlation coefficients. Outcome measures including visual analog scale (VAS) score, passive range of motion (ROM), and shoulder pain and disability index (SPADI) score were evaluated at baseline and 4 weeks after treatment. Comparisons between patients with good and poor clinical outcomes were performed with independent t-test, Mann-Whitney U test, and chi-square test. Logistic regression was used to identify predictors of good clinical outcomes. A P value <0.05 defined significance. Results: Access to the glenohumeral joint was successful in 87.5% patients on the first attempt. The infused fluid volume was 21.0±3.40 mL. Longer symptom duration (r=-0.676, P<0.001), greater SPADI (r=-0.148, P=0.007), and decreased ROM in abduction (r=0.38, P=0.016) were associated with a decreased volume of infused fluid. CEUS detected massive fluid leakage in 5 (12.5%) patients, with 4 capsule ruptures confirmed by magnetic resonance imaging (MRI). Longer symptom duration (r=0.485, P=0.001), decreased ROM in the direction of abduction (r=-0.33, P=0.037), and external rotation (r=-0.34, P=0.032) were correlated with an increased incidence of massive fluid leakage. Moreover, patients with good outcomes had significantly shorter symptom duration (5.7±2.09 vs. 11.2±3.89 months, P=0.002) and greater initial VAS score (6.9±1.04 vs. 6.3±0.50, P=0.022) than those with poor outcomes. Absence of massive fluid leakage was an independent predictor of clinical good outcomes at 4 weeks after treatment [odd ratio (OR) =0.05, 95% confidential interval (CI): 0.003-0.882, P=0.041]. Conclusions: CEUS-guided capsule-preserving hydrodilatation allows real-time visualization of capsule dilatation, accurate detection of extracapsular fluid leakage, and identification of risks for capsule rupture. It provides an effective treatment for AC, and is useful to predict patients' clinical outcomes.

13.
Rev Sci Instrum ; 95(6)2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38869360

RESUMO

We describe a high-performance molecular iodine optical frequency reference that is referenced to the R(56)32-0: a1 hyperfine transition of molecular iodine based on modulation transfer spectroscopy. We design an unsaturated iodine vapor cell with a gas pressure equivalent to the saturation pressure at -17 °C. Using this cell, we developed a compact, frequency-stabilized laser. The iodine cell operates at room temperature and is not actively temperature stabilized. We demonstrate a laser with fractional frequency instability of 1.4 × 10-14 at 1 s and 1.7 × 10-15 at 104 s. To our knowledge, the level of frequency instability at 104 s is comparable to the previously reported best results for an iodine stabilized laser. These results suggest that using an unsaturated iodine vapor cell is a valid approach for the development of long-term, stable iodine-based optical references.

14.
Clin Breast Cancer ; 24(3): e167-e176, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38212189

RESUMO

BACKGROUND: There are significant correlations between the levels of tumor infiltrating lymphocytes (TILs) and the prognosis of primary breast cancer. While little is known about immunological mechanisms in the distant metastasis of advanced breast cancer. PATIENTS AND METHODS: A total of 106 patients with advanced metastatic breast cancer were enrolled in this study between 2016 and 2022. Hematoxylin and eosin staining and immunohistochemistry were used to assess the densities of stromal TILs (sTILs), intratumoral TILs (iTILs) and invasive marginal TILs (imTILs) and CD4+, CD8+, CD20+, FOXP3+ TILs in the primary tumor and metastasis (bone, lung, liver, and distant lymph node) of advanced breast cancer. RESULTS: Higher levels of sTILs at metastatic sites were associated with better progression-free survival (PFS), postmetastasis survival (PMS) and overall survival (OS) (p = .026, .001 and .005, respectively). The levels of iTILs were significantly lower than those of sTILs and imTILs in both primary tumor (p< .001, both) and metastasis (p< .001, both). The level of CD4+ T cells was higher than those of CD8+ T cells and CD20+ B cells in both primary tumor (p < .001) and metastasis (p < .001). The levels of sTILs (p=0. 001) and imTILs (p< .001) in the primary tumor were generally higher than those in the metastasis. CONCLUSION: The levels of TILs and their subsets can predict the survival and prognosis of patients with advanced breast cancer. The distributions of TILs and their subsets are similar between the primary tumor and metastasis. The metastases have a lower degree of lymphocytes infiltration than its corresponding primary tumor.


Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/patologia , Prognóstico , Linfócitos do Interstício Tumoral , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos
15.
Cancer Res Treat ; 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38993092

RESUMO

Purpose: The genomic characteristics of uterine sarcomas have not been fully elucidated. This study aimed to explore the genomic landscape of the USs. Materials and Methods: Comprehensive genomic analysis through RNA-sequencing was conducted. Gene fusion, differentially expressed genes (DEGs), signaling pathway enrichment, immune cell infiltration, and prognosis were analyzed. A deep learning model was constructed to predict the survival of US patients. Results: A total of 71 US samples were examined, including 47 endometrial stromal sarcomas (ESS), 18 uterine leiomyosarcomas (uLMS), 3 adenosarcomas, 2 carcinosarcomas, and 1 uterine tumor resembling an ovarian sex-cord tumor (UTROSCT). ESS (including high-grade ESS and low-grade ESS) and uLMS showed distinct gene fusion signatures; a novel gene fusion site, MRPS18A - PDC-AS1 could be a potential diagnostic marker for the pathology differential diagnosis of uLMS and ESS; 797 and 477 uDEGs were identified in the ESS vs. uLMS and HGESS vs. LGESS groups, respectively. The uDEGs were enriched in multiple pathways. Fifteen genes including LAMB4 were confirmed with prognostic value in USs; immune infiltration analysis revealed the prognositic value of myeloid dendritic cells, plasmacytoid dendritic cells, natural killer cells, macrophage M1, monocytes and hematopoietic stem cells in USs; the deep learning model named MMN-MIL showed satisfactory performance in predicting the survival of US patients, with the area under the receiver operating curve curve reached 0.909 and accuracy achieved 0.804. Conclusion: USs harbored distinct gene fusion characteristics and gene expression features between HGESS, LGESS, and uLMS. The MMN-MIL model could effectively predict the survival of US patients.

16.
Insights Imaging ; 14(1): 104, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37286810

RESUMO

OBJECTIVES: This study aims to develop and validate a virtual biopsy model to predict microsatellite instability (MSI) status in preoperative gastric cancer (GC) patients based on clinical information and the radiomics of deep learning algorithms. METHODS: A total of 223 GC patients with MSI status detected by postoperative immunohistochemical staining (IHC) were retrospectively recruited and randomly assigned to the training (n = 167) and testing (n = 56) sets in a 3:1 ratio. In the training set, 982 high-throughput radiomic features were extracted from preoperative abdominal dynamic contrast-enhanced CT (CECT) and screened. According to the deep learning multilayer perceptron (MLP), 15 optimal features were optimized to establish the radiomic feature score (Rad-score), and LASSO regression was used to screen out clinically independent predictors. Based on logistic regression, the Rad-score and clinically independent predictors were integrated to build the clinical radiomics model and visualized as a nomogram and independently verified in the testing set. The performance and clinical applicability of hybrid model in identifying MSI status were evaluated by the area under the receiver operating characteristic (AUC) curve, calibration curve, and decision curve (DCA). RESULTS: The AUCs of the clinical image model in training set and testing set were 0.883 [95% CI: 0.822-0.945] and 0.802 [95% CI: 0.666-0.937], respectively. This hybrid model showed good consistency in the calibration curve and clinical applicability in the DCA curve, respectively. CONCLUSIONS: Using preoperative imaging and clinical information, we developed a deep-learning-based radiomics model for the non-invasive evaluation of MSI in GC patients. This model maybe can potentially support clinical treatment decision making for GC patients.

17.
J Am Chem Soc ; 134(27): 11124-7, 2012 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-22734716

RESUMO

Practical catalytic cross-coupling of secondary alkyl electrophiles with secondary alkyl nucleophiles under Cu catalysis has been realized. The use of TMEDA and LiOMe is critical for the success of the reaction. This cross-coupling reaction occurs via an S(N)2 mechanism with inversion of configuration and therefore provides a general approach for the stereocontrolled formation of C-C bonds between two tertiary carbons from chiral secondary alcohols.

18.
Angew Chem Int Ed Engl ; 51(2): 528-32, 2012 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-22135233

RESUMO

Easy access: An unprecedented copper-catalyzed cross-coupling reaction of the title compounds with diboron reagents is described (see scheme; Ts = 4-toluenesulfonyl). This reaction can be used to prepare both primary and secondary alkylboronic esters having diverse structures and functional groups. The resulting products would be difficult to access by other means.


Assuntos
Compostos de Boro/síntese química , Cobre/química , Alquilação , Compostos de Boro/química , Catálise , Ésteres/síntese química , Ésteres/química
19.
Anal Methods ; 14(31): 2961-2975, 2022 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-35913361

RESUMO

Electrochemical methodology has probably been the most used sensing platform in the past few years as they provide superior advantages. In particular, screen-printed electrode (SPE)-based sensing applications stand out as they provide extraordinary miniaturized but robust and user-friendly detection system. In this context, we are focusing on the modification of SPE with functional nucleic acid probes and nanostructures to improve the electrochemical detection performance in versatile sensing applications, particularly in the fight against the COVID-19 pandemic. Aptamers are immobilized on the electrode surface to detect non-nucleic acid targets and complementary probes to recognize and capture nucleic acid targets. In a step further, SPE-based biosensors with the modification of self-assembled DNA nanostructures are emphasized as they offer great potential for the interface engineering of the electrode surface and promote the excellent performance of various interface reactions. By equipping with a portable potentiostat and a smartphone monitoring device, the realization of this SPE-based miniaturized diagnostic system for the further requirement of fast and POC detection is revealed. Finally, more novel and excellent works are previewed and future perspectives in this field are mentioned.


Assuntos
Técnicas Biossensoriais , COVID-19 , Técnicas Biossensoriais/métodos , COVID-19/diagnóstico , Eletrodos , Humanos , Sondas de Ácido Nucleico , Pandemias
20.
PeerJ ; 10: e13488, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35611170

RESUMO

Background: The purpose of this paper was to explore the correlation between multiple tumor markers and newly diagnosed gastric cancer. Methods: We selected 268 newly diagnosed patients with gastric cancer and 209 healthy subjects for correlation research. The detection of multiple tumor markers was based on protein chips and the results were statistically analyzed using SPSS. Results: We concluded that gastric cancer was significantly related to gender, age, alpha fetoprotein (AFP), carcinoembryonic antigen (CEA), carbohydrate antigen 125 (CA125), carbohydrate antigen 199 (CA199), and carbohydrate antigen 242 (CA242) positive levels (P < 0.001). After CA199 and CA242 were stratified by gender, the male odds ratio (OR) was 30.400 and 31.242, respectively, while the female OR was 3.424. After CA125 was stratified by age in patients over 54 years old with gastric cancer, the risk of occurrence in the CA125-positive population was 16.673 times that of the CA125-negative patients. Among patients 54 years old and younger, being CA125-positive was not a risk factor for gastric cancer (P = 0.082). AFP, CEA, CA125, CA199, and CA242 positive levels during the M1 stage were statistically significant when compared with the M0 stage and control group (P < 0.001), but the AFP (P = 0.045) and CA125 (P = 0.752) positive levels were not statistically significant when compared with the M0 stage and control group. The combined detection sensitivity of multiple tumor markers was 44.78%. Conclusion: Our research shows that gastric cancer is associated with age, gender, and the positive levels of AFP, CEA, CA125, CA199, and CA242. The positive levels of AFP and CA125 were related to the distant metastasis of gastric cancer. To a certain extent, the combined detection sensitivity can be used for the initial screening of gastric cancer.


Assuntos
Biomarcadores Tumorais , Neoplasias Gástricas , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Antígeno Carcinoembrionário , alfa-Fetoproteínas/metabolismo , Estudos Retrospectivos , Neoplasias Gástricas/diagnóstico , Prognóstico , Antígeno Ca-125 , Carboidratos
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