Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 35
Filter
Add more filters











Publication year range
1.
Curr Med Imaging ; 2023 Aug 04.
Article in English | MEDLINE | ID: mdl-37537936

ABSTRACT

BACKGROUND: Spectral-Domain Optical Coherence Tomography (SD-OCT) provides non-invasive, high-speed, high-resolution, three-dimensional cross-section imaging of the macula. OBJECTIVES: This study aimed to investigate the diagnostic value of the multimodal imaging technique of three-dimension (3D) optical coherence tomography (OCT) (3D-OCT) for the diagnosis and characterization of acute central serous chorioretinopathy (CSC). METHODS: In this prospective clinical study 3D-OCT examinations of 82 cases with acute CSC were performed on the macular area, and the image characteristics were analyzed. Our study included a total of 87 eyes from 82 cases of CSC patients, 67 males and 15 females (mean age ± standard deviation (SD): 42.89 ±7.80 years old; age range: 27 to 56 years old. The 3D-OCT images were evaluated for the presence of subretinal fluid, subretinal space, fluctuation of the internal limiting membrane (ILM), folds of retinal pigment epithelial (RPE), retinal pigment epithelium detachment (PED), and flat irregular PED. The foveal thickness was measured using the manual caliper of OCT software. RESULTS: The OCT B-scan images showed 87 (100%) eyes had exudative retinal detachment (ERD), 38 (44%) had flat irregular PED, 36 (41%) had PED, 8 (9%) had subretinal turbidity structure, 2 (2%) had subretinal dot-like precipitates, 1 (1%) had focal choroidal excavation (FCE), and 1 (1%) eye had fluctuation of internal limiting membrane (FI). In the ILM-RPE thickness map, all eyes had a round or round like regular uniform domes. Fifty-seven (66%) domes were limited in the examination area and 30 (44%) domes were beyond the scope of this examination and only a partial section of the dome could be observed. In the en-face image, all eyes had a round or round-like black figure that corresponded with domes in the ILM-RPE thickness map. In RPE surface, 76 (87%) eyes had a shallow plate depression, 71(82%) had small focal uplift, and 1 (1%) eye had a focal concave feature. CONCLUSIONS: In the OCT ILM-RPE thickness, en-face image, and RPE surface maps, acute CSC exhibited specific imaging characteristics that can be helpful for reliable diagnosis and differential diagnosis of CSC.

2.
Med Sci Monit ; 24: 687-697, 2018 Feb 03.
Article in English | MEDLINE | ID: mdl-29396390

ABSTRACT

BACKGROUND This study analyzed the macular 3D-OCT images of Vogt-Koyanagi-Harada disease (VKH) in uveitis, explored the characteristics of 3D-OCT images of the macular region of VKH, and assessed which characteristics contribute most to VKH diagnosis. MATERIAL AND METHODS The 3D-OCT examination of 25 cases of VKH was performed on the macular area, and the image characteristics were analyzed. RESULTS Our study included a total of 50 eyes from 25 cases of VKH patients, 10 males and 15 females, aged 17 to 64 years, mean (39.44±11.60) years old. According to OCT B-scan images, 49 (98%) eyes had ERD, 49 (98%) eyes had nerve retinal edema, 36 (72%) eyes had endometrium-like structure (including cysts), 5 (10%) eyes had RPE folds, 35 (70%) eyes had changes in the internal septum, 49 (98%) eyes had RPE monolayer structure outside the ERD region. In ILM-RPE thickness, 49 (98%) eyes had retinal irregular thickening and 31 (62%) eyes had radial stripe changes. In ILM contour figure, 50 eyes (100%) showed exceptional uplift, 5 (10%) eyes had small focal uplift for PED on the RPE surface, and 48 (96%) eyes had wavy ups and downs. CONCLUSIONS In OCT B-scan imaging, the ERT, retinal edema of the retina, and the RPE monolayer structure outside the range are most likely to occur in VKH. The ILM-RPE thickness chart in 3D reconstruction showed irregular thickening of the retina. The ILM contour graph showed abnormal uplift, and RPE surface wavy ups and downs in VKH most likely to occur.


Subject(s)
Imaging, Three-Dimensional , Tomography, Optical Coherence , Uveitis/complications , Uveitis/diagnosis , Uveomeningoencephalitic Syndrome/complications , Uveomeningoencephalitic Syndrome/diagnosis , Adolescent , Adult , Demography , Female , Fundus Oculi , Humans , Macula Lutea/pathology , Male , Middle Aged , Uveitis/physiopathology , Uveomeningoencephalitic Syndrome/physiopathology , Visual Acuity , Young Adult
3.
Sci Rep ; 4: 6769, 2014 Oct 27.
Article in English | MEDLINE | ID: mdl-25346284

ABSTRACT

Building on previous research on the origin and homochirality of life, this study focuses on analyses profiling important building blocks of life: the natural amino acids. The spark discharge variation of the iconic Miller experiment was performed with a reducing gas mixture of ammonia, methane, water and hydrogen. Amino acid analysis using liquid chromatography coupled with tandem mass spectrometry after pre-column derivatizaiton revealed the generation of several amino acids including those essential for life. Re-crystallization of the synthetic products and enantiomeric ratio analysis were subsequently performed. Results from liquid chromatography coupled with either fluorescent detector or tandem mass spectrometry after pre-column derivatization with chiral reagent revealed spontaneous and effective asymmetric resolution of serine and alanine. This work describes a useful analytical platform for investigation of hypotheses regarding the origin and homochirality of amino acids under prebiotic conditions. The formation of numerous amino acids in the electric discharge experiment and the occurrence of high enantiomeric ratios of amino acids in re-crystallization experiment give valuable implications for future studies in unraveling fundamental questions regarding origins and evolution of life.


Subject(s)
Amino Acids/chemistry , Amino Acids/chemical synthesis , Chromatography, Liquid , Crystallization , Tandem Mass Spectrometry
6.
Chemistry ; 17(28): 7904-17, 2011 Jul 04.
Article in English | MEDLINE | ID: mdl-21611987

ABSTRACT

The development, scope, and application of the highly enantioselective organocatalytic aziridination of α,ß-unsaturated aldehydes is presented. The aminocatalytic azirdination of α,ß-unsaturated aldehydes enables the asymmetric formation of ß-formyl aziridines with up to >19:1 d.r. and 99% ee. The aminocatalytic aziridination of α-monosubstituted enals gives access to terminal α-substituted-α-formyl aziridines in high yields and up to 99% ee. In the case of the organocatalytic aziridination of disubstituted α,ß-unsaturated aldehydes, the transformations were highly diastereo- and enantioselective and give nearly enantiomerically pure ß-formyl-functionalized aziridine products (99% ee). A highly enantioselective one-pot cascade sequence based on the combination of asymmetric amine and N-heterocyclic carbene catalysis (AHCC) is also disclosed. This one-pot three-component co-catalytic transformation between α,ß-unsaturated aldehydes, hydroxylamine derivatives, and alcohols gives the corresponding N-tert-butoxycarbonyl and N-carbobenzyloxy-protected ß-amino acid esters with ee values ranging from 92-99%. The mechanisms and stereochemistry of all these catalytic transformations are also discussed.

9.
Chemistry ; 16(5): 1585-91, 2010 Feb 01.
Article in English | MEDLINE | ID: mdl-20039352

ABSTRACT

The first examples of one-pot highly chemo- and enantioselective dynamic kinetic asymmetric transformations (DYKATs) involving alpha,beta-unsaturated aldehydes and propargylated carbon acids are presented. These DYKATs, which proceed by a combination of catalytic iminium activation, enamine activation, and Pd(0)-catalyzed enyne cycloisomerization, give access to functionalized cyclopentenes with up to 99 % ee and can be used for the generation of all-carbon quaternary stereocenters.


Subject(s)
Amines/chemistry , Cyclopentanes/chemical synthesis , Palladium/chemistry , Transition Elements/chemical synthesis , Catalysis , Cyclization , Cyclopentanes/chemistry , Kinetics , Molecular Dynamics Simulation , Molecular Structure , Stereoisomerism , Transition Elements/chemistry
10.
Macromol Rapid Commun ; 31(8): 740-4, 2010 Apr 20.
Article in English | MEDLINE | ID: mdl-21590965

ABSTRACT

A simple and direct method for derivatization of solid polysaccharides is presented. The novel methodology is based on the combination of organic acid-catalyzed esterification or etherification and photochemical thiol-ene click derivatization of a heterogeneous polysaccharide. The solid cellulose was "organoclick" modified with aryl, alkyl and polyester groups, respectively. The modification allows for a highly modular and metal free surface modification of solid polysaccharides.

12.
Ying Yong Sheng Tai Xue Bao ; 19(9): 1865-70, 2008 Sep.
Article in Chinese | MEDLINE | ID: mdl-19102295

ABSTRACT

Based on the urban forest coverage data interpreted from QuickBird image (2006) and the CITYgreen model, the benefits of Shenyang urban forest types with different canopy closure in carbon fixation and pollutant removal were investigated by means of sampling strategy. The results showed that the total amount of carbon storage, annual carbon sequestration, annual air pollutant removal, and their corresponding values were 0.51 Tg, 6858.20 Mg x a-1), 556.04 Mg x a(-1) 1.26 x 10(8) Yuan, 1.72 x 10(6) Yuan, and 0.22 x 10(8) Yuan, respectively. Among the urban forest types in Shenyang City, ecological and public welfare forest (E) contributed most to the carbon fixation and air pollutant removal. The carbon density decreased in the order of S (subordinated forest) > L (landscape and relaxation forest) > P (production and management forest) > E > R (road forest), annual carbon sequestration was in the order of P > L > E > S > R, and annual air pollutant removal was in the order of P > L > S > E > R. The carbon density of different urban forest types was closely related to their structural complexity. For the forests with high canopy closure, both the annual carbon sequestration and the annual pollutant removal were high; while for those with lower canopy closure, these two characteristics were dependent on the structural complexity of the forests.


Subject(s)
Carbon/analysis , City Planning , Ecosystem , Trees/growth & development , Air Pollutants/analysis , Air Pollution/analysis , Air Pollution/prevention & control , Biomass , China , Environmental Monitoring/methods
13.
J Integr Plant Biol ; 50(9): 1130-9, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18844781

ABSTRACT

The conserved domains of reverse transcriptase (RT) genes of Ty1-copia and Ty3-gypsy groups of long terminal repeat (LTR) retrotransposons were isolated from the Malus domestica genome using degenerate oligonucleotide primers. Sequence analysis showed that 45% of Ty1-copia and 63% of Ty3-gypsy RT sequences contained premature stop codons and/or indels disrupting the reading frame. High heterogeneity among RT sequences of both Ty1-copia and Ty3-gypsy group retrotransposons was observed, but Ty3-gypsy group retrotransposons in the apple genome are less heterogeneous than Ty1-copia elements. Retrotransposon copy number was estimated by dot blot hybridizations for Ty1-copia (approximately 5,000) and Ty3-gypsy (approximately 26,000). All elements of the two types of LTR retrotransposons comprise approximately 38% of the M. domestica genome, with the Ty3-gypsy group contribution being higher (33.5%) than the Ty1-copia one (4.6%). Transcription was not detected by reverse transcription-polymerase chain reaction for either Ty1-copia or Ty3-gypsy retrotransposons in the leaves of plants in vitro or in leaf explants cultured on medium supplemented with high concentration benzylaminopurine. This research reveals the differences in heterogeneity and copy number between Ty1-copia and Ty3-gypsy retrotransposons in the apple genome. Ty1-copia retrotransposon has higher heterogeneity than Ty3-gypsy retrotransposon, but the latter has a higher copy number, which implies that Ty3-gypsy retrotransposons may play a more important role in the apple genome evolution.


Subject(s)
Gene Dosage , Genome, Plant/genetics , Malus/genetics , Retroelements/genetics , Terminal Repeat Sequences/genetics , Amino Acid Sequence , Base Sequence , DNA, Plant/genetics , DNA, Plant/isolation & purification , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction , Sequence Alignment , Transcription, Genetic
14.
Chemistry ; 14(32): 10007-11, 2008.
Article in English | MEDLINE | ID: mdl-18830983

ABSTRACT

A highly enantioselective organocatalytic one-pot synthesis of nitro-, formyl-, and ester-functionalized cyclopentanes with four stereocenters is presented. The cyclopentanes were formed as a predominant diasteroisomer and isolated in high yields with 97-99 % ee.

16.
Ying Yong Sheng Tai Xue Bao ; 19(6): 1173-8, 2008 Jun.
Article in Chinese | MEDLINE | ID: mdl-18808004

ABSTRACT

Based on the fractal theory of forest growth, stepwise regression was employed to pursue a convenient and efficient method of measuring the three-dimensional green biomass (TGB) of urban forests in small area. A total of thirteen simulation equations of TGB of urban forests in Shenyang City were derived, with the factors affecting the TGB analyzed. The results showed that the coefficients of determination (R2) of the 13 simulation equations ranged from 0.612 to 0.842. No evident pattern was shown in residual analysis, and the precisions were all higher than 87% (alpha = 0.05) and 83% (alpha = 0.01). The most convenient simulation equation was ln Y = 7.468 + 0.926 lnx1, where Y was the simulated TGB and x1 was basal area at breast height per hectare (SDB). The correlations between the standard regression coefficients of the simulation equations and 16 tree characteristics suggested that SDB was the main factor affecting the TGB of urban forests in Shenyang.


Subject(s)
Biomass , Cities , Ecosystem , Trees/growth & development , China , City Planning , Computer Simulation , Conservation of Natural Resources , Models, Theoretical , Regression Analysis
17.
Chemistry ; 14(26): 7867-79, 2008.
Article in English | MEDLINE | ID: mdl-18618876

ABSTRACT

The development of one-pot organocatalytic domino Michael/alpha-alkylation reactions between bromomalonates or bromoacetoacetate esters and alpha,beta-unsaturated aldehydes is presented. The chiral-amine-catalyzed reactions with bromomalonates as substrates give access to the corresponding 2-formylcyclopropane derivatives in high yields with excellent diastereoselectivity and up to 99 % ee. The catalytic domino Michael/alpha-alkylation reactions between 4-bromo-acetoacetate and enals provide a route for the synthesis of functionalized cyclopentanones in good to high yields with 93-99 % ee. The products from the organocatalytic reactions were also reduced with high diastereoselectivity to the corresponding cyclopropanols and cyclopentanols, respectively. Moreover, one-pot combinations of amine and heterocyclic carbene catalysis (AHCC) enabled the highly enantioselective synthesis of beta-malonate esters (91-97 % ee) from the reaction between bromomalonates and enals. The tandem catalysis included the catalytic domino reaction followed by catalytic in situ chemoselective ring-opening of the 2-formylcyclopropane intermediates.

18.
Chemistry ; 14(9): 2693-8, 2008.
Article in English | MEDLINE | ID: mdl-18228546

ABSTRACT

A regiospecific, highly chemo-, diastereo-, and enantioselective one-pot catalytic cascade synthesis of cycloheptane derivatives is presented. In this chiral-amine-catalyzed asymmetric process, six new bonds and five new stereocenters were formed with excellent stereocontrol (>25:1 d.r. and 98- >99 ee).


Subject(s)
Cycloheptanes/chemical synthesis , Catalysis , Crystallography, X-Ray , Cyclization , Cycloheptanes/chemistry , Magnetic Resonance Spectroscopy/methods , Magnetic Resonance Spectroscopy/standards , Models, Molecular , Molecular Structure , Reference Standards , Stereoisomerism
19.
Ying Yong Sheng Tai Xue Bao ; 18(6): 1208-12, 2007 Jun.
Article in Chinese | MEDLINE | ID: mdl-17763717

ABSTRACT

Based on ARC/GIS and by using the method of "planar biomass estimation", the green biomass (GB) of Shenyang urban forests was measured. The results demonstrated that the GB per unit area was the highest (3.86 m2.m(-2)) in landscape and relaxation forest, and the lowest (2.27 m2.m(-2)) in ecological and public welfare forest. The GB per unit area in urban forest distribution area was 2.99 m2.m(-2), and that of the whole Shenyang urban area was 0.25 m2.m(-2). The total GB of Shenyang urban forests was about 1.13 x 10(8) m2, among which, subordinated forest, ecological and public welfare forest, landscape and relaxation forest, road forest, and production and management forest accounted for 36.64% , 23.99% , 19.38% , 16.20% and 3.79%, with their GB being 4. 15 x 10(7), 2.72 x 10(7), 2.20 x 10(7), 1.84 x 10(7) and 0.43 x 10(7) m2, respectively. The precision of the method "planar biomass estimation" was 91.81% (alpha = 0.05) by credit test.


Subject(s)
Biomass , City Planning , Ecosystem , Trees/growth & development , China , Geographic Information Systems , Humans
20.
Chem Commun (Camb) ; (7): 734-5, 2007 Feb 21.
Article in English | MEDLINE | ID: mdl-17392966

ABSTRACT

The highly enantioselective direct organocatalytic conjugate addition of aldehydes to maleimides is presented.


Subject(s)
Aldehydes/chemistry , Maleimides/chemistry , Catalysis , Molecular Conformation , Stereoisomerism , Succinimides/chemical synthesis
SELECTION OF CITATIONS
SEARCH DETAIL