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Sheng Yao

Publications and source records attributed to Sheng Yao.

At least 19 recordsLinked to original sources
PubMed2026

A chromosome-level assembly of the alpine snow alga Chloromonas typhlos.

Chloromonas typhlos is a cosmopolitan alpine snow alga distributed across continents, and its blooming accelerates snow melting by decreasing the amount of snow albedo. To elucidate the genetic traits underlying the adaptation of C. typhlos to the alpine habitat, we combined PacBio sequencing and Hi-C to generate a high-quality chromosome-level genome assembly (contig N50: 1.29 Mb; scaffold N50: 7.23 Mb) with 31 chromosomes and a genome size of 200.86 Mb. Repetitive elements constituted 11.05% of the genome, and 16,133 protein-coding genes were predicted, of which 82% were functionally annotated. This study provides a set of omics resources both for snow algae and the genus Chloromonas.

Snow↗
PubMed2007

One- and two-photon singlet oxygen generation with new fluorene-based photosensitizers.

The spectral properties of new fluorene-based photosensitizers for efficient singlet oxygen production are investigated at room temperature and 77 K. Two-photon absorption (2PA) cross-sections of the fluorene derivatives are measured by the open aperture Z-scan method. The quantum yields of singlet oxygen generation under one- and two-photon excitation (phi(delta) and 2PAphi(delta), respectively), are determined by the direct measurement of singlet oxygen luminescence at approximately 1270 nm. The values of phi(delta) are independent of excitation wavelength, ranging from 0.6-0.9. The singlet oxygen quantum yields under two-photon excitation are 2PAphi(delta) approximately 1/2 phi(delta), indicating that the two processes exhibit the same mechanism of singlet oxygen production, independent of the mechanism of photon absorption.

Fluorenes↗
PubMed2006

Two-photon photochromism of a diarylethene enhanced by Förster resonance energy transfer from two-photon absorbing fluorenes.

Resonance energy transfer from two-photon absorbing fluorene derivatives to the photochromic compound 3,4-bis-(2,4,5-trimethyl-thiophen-3-yl)furan-2,5-dione (PC 1) is investigated in hexane under one- and two-photon excitation. The quenching of the steady-state fluorescence of donor molecules in the presence of the diarylethene acceptor is used to study the nature of resonance energy transfer. The Förster distances and critical acceptor concentrations are determined for nonbound donor-acceptor pairs in homogeneous molecular ensembles. Quite significantly, up to a two-fold enhancement in the velocity of the photochromic transformation of 1, in the presence of two-photon absorbing fluorene derivatives, is demonstrated.

Ethylenes↗
PubMed2006

[Immunopathological changes of micro-vessels in dermatomyositis].

OBJECTIVE: To investigate the immunopathological changes of micro-vessels in dermatomyositis. METHODS: Twelve patients with dermatomyositis, 5 males and 7 females, aged 40.8 (6 - 72), underwent muscle biopsy of biceps muscle of arm (n = 11) or deltoid muscle (n = 1). The specimens underwent routine histological, enzyme histochemical, and immunohistochemical staining and microscopy. Ten biopsy specimens from patients with other diseases were used as controls. RESULTS: Perifascicular atrophy of muscular fibers and inflammatory infiltration in perimysium were seen in all patients with dermatomyositis. Non-specific esterase staining showed deep staining of capillaries and micro vascular endothelium among the muscular fibers. Immunohistochemistry showed remarkable reduction of capillaries positive in von Willebrand factor (vWF), thrombomodulin (TM), and endothelial cell nitric oxide synthase (eNOS) in the perifascicular region, and low expression of .eNOS and TM in the microvascular endothelium in the perimysium. CONCLUSION: The vascular lesions of dermatomyositis are located not only in capillaries, but also in other microvessels. Lower expression of TM and eNOS in vascular endothelium suggests the reduction of anticoagulation and vasodilation functions of vascular endothelium. Dermatomyositis is an inflammatory vascular endothelial disease.

Adolescent↗
PubMed2006

The impact of the pi-electron conjugation length on the three-photon absorption cross section of fluorene derivatives.

The three-photon absorption cross sections of three different fluorene derivatives, with extended pi-electron conjugation lengths was experimentally measured and compared with shorter pi-electron conjugation length analogs. The effect of the conjugation length on the three-photon absorption cross section sigma(3) (') of this family of molecules has been elucidated. It is demonstrated that sigma(3) (') of the asymmetric compound D-pi-pi-pi-A is 6.6 times larger than its shorter configuration D-pi-A, while for the symmetric compounds D-pi-pi-pi-D and A-pi-pi-pi-A a two-fold enhancement was found relative to their shorter conjugation length analogs. Measurements of the three-photon excitation of these compounds in THF solution (10(-3)M) were accomplished with a tunable optical pulse generation pumped by a 25 ps Nd-YAG laser.

Journal Article↗
PubMed2006

Reviving exhausted T lymphocytes during chronic virus infection by B7-H1 blockade.

Cytotoxic T lymphocytes (CTLs) are killer cells that are crucial in the control of viral pathogens and cancers. They can become exhausted during chronic viral infection, a phenomenon that consists of a reduction in both number and functionality of CTLs. Recently, Barber and colleagues demonstrated that B7-H1 (also called PD-L1), a cell-surface molecule that is widely distributed in tissues, was necessary for the maintenance of T-cell exhaustion in a chronic-infection mouse model of lymphocytic choriomeningitis virus (LCMV). PD-1, the receptor of B7-H1, was greatly upregulated on CTLs in response to LCMV, and its expression was maintained during chronic infection. Blockade of the B7-H1-PD-1 pathway by a monoclonal antibody restored CTL function and reduced viral burden. These results suggest a new strategy for the treatment of chronic viral infection.

Animals↗
PubMed2006

Interferon regulatory factor-1 is prerequisite to the constitutive expression and IFN-gamma-induced upregulation of B7-H1 (CD274).

Majority of cancer cells upregulate co-inhibitory molecule B7-H1 which confers resistance to anti-tumor immunity, allowing cancers to escape from host immune surveillance. We addressed the molecular mechanism underlying the regulation of cancer-associated B7-H1 expression in response to interferon-gamma (IFN-gamma). Using promoter constructs in luciferase assay, the region between 202 and 320 bp from the translational start site is responsible for B7-H1 expression. Electrophoretic mobility shift assay, site-directed mutagenesis and knockdown experiment using siRNA revealed that interferon regulatory factor-1 (IRF-1) is primarily responsible for the constitutive B7-H1 expression as well as for the IFN-gamma-mediated B7-H1 upregulation in a human lung cancer cell line A549. Additionally, AG490, a Janus activated kinase/signal transducer and activator of transcription inhibitor, greatly abolished the responsiveness of A549 cells to IFN-gamma by reducing the IRF-1 transcription. Our findings support a critical role of IRF-1 in the regulation of constitutive and IFN-gamma-induced expression of B7-H1 in cancer cells.

Antigens, CD↗
PubMed2006

[Two novel mutations in palmitoyl-protein thioesterase gene in two Chinese babies with infantile neuronal ceroid lipofuscinosis].

OBJECTIVE: To search for possible novel mutations in palmitoyl-protein thioesterase 1 (PPT1) gene in two Chinese babies with infantile neuronal ceroid lipofuscinosis (INCL). METHODS: Two probands with INCL, confirmed clinically and pathologically, were used for mutation search in PPT1 gene. Onset of the disease occurred before the age of 1 year and they mainly showed progressive mental and motor retardation. The 9 coding exons and their flanking intron sequences of palmitoyl-protein thioesterase 1 (PPT1) gene were amplified by using PCR and sequenced. The parents of proband 1 were also examined. RESULTS: One splicing mutation and two missense mutations were identified in the two probands: the proband 1 carrying a compound heterozygous mutation of a IVS1 + 1G-->A mutation in intron 1 and a c550G-->A mutation in exon 6 leading to the amino acid substitution of E184K. Additionally, the parents of the proband 1 also harbored one of the mutations of the patient, respectively. The proband 2 carrying a homozygous mutation of c272A-->C in exon 3, which resulted in the amino acid substitutions of Q91P. CONCLUSIONS: The IVS1 + 1G-->A mutation and Q91P mutation are novel mutations, which lead to INCL. The genetic abnormalities of PPT1 in Chinese patients may not be completely the same as those in the patients of other regions of the world.

Age of Onset↗
PubMed2005

Mega three-photon absorption cross-section enhancement in pseudoisocyanine J-aggregates.

Herein we report an extraordinary three-photon absorption cross-section (sigma'3) enhancement in J-aggregates supramolecular systems. The much higher value of sigma'3 in PIC J-aggregate (2.5 x 10(-71) cm6 s2 ph(-2)) compared to typical values obtained in organic molecules (10(-80) cm6 s2 ph(-2)) is attributed to the strong molecular transition dipole moment coupling in the supramolecular assembly. Three-photon absorption of PIC J-aggregates and monomer aqueous solutions were measured using the well known open aperture Z-scan technique pumping with a 25 ps pulse laser-OPG system at 1720 nm. This novel result opens new expectations for applications of supramolecular systems in bioimaging and medicine.

Absorption↗
PubMed2005

Excited-state absorption and anisotropy properties of two-photon absorbing fluorene derivatives.

The electronic structure of fluorene derivatives N-(7-benzothiazol-2-yl-9,9-bis-decyl-9H-fluoren-2-yl)-acetamide (1); 9,9-didecyl-2,7-bis-(N,N-benzothiazoyl)fluorene (2); 4,4'-{[9,9-bis(ethyl)-9H-fluorene-2,7-diyl]di-2,1-ethenediyl}bis(N,N-diphenyl)benzeneamine (3); and 4,4',4"{[9,9-bis(ethyl)-9H-fluorene-2,4,7-triyl]tri-2,1-ethenediyl}tris(N,N-diphenyl)benzeneamine (4) were investigated by a steady-state spectral technique, quantum-chemical calculations, and a picosecond pump-probe method. These derivatives are of interest for their relatively high two-photon absorption. The steady-state excitation anisotropy spectra reveal the nature of the ground-state absorption bands. Semiempirical quantum-chemical calculations of the fluorene derivatives (AM1, ZINDO/S) show good agreement with experimental data. The spectral positions and alignment of various electronic transitions of derivatives 1-4 were estimated from their excited-state absorption and anisotropy spectra.

Absorption↗
PubMed2005

Synthesis of two-photon absorbing unsymmetrical branched chromophores through direct tris(bromomethylation) of fluorene.

Branched fluorene-based chromophores bearing electron-donating diphenylamino or electron-withdrawing nitro groups were synthesized as well as their linear analogues. An efficient synthetic method was developed via a novel 2,4,7-tris(bromomethyl)-9,9-diethylfluorene intermediate. The bromomethyl groups in this key intermediate were converted to either phosphonate or carboxaldehyde moieties, facilitating preparation of a high functionality branched structure. It was found that the reactivity at position 4 is attenuated in the bromomethyl and phosphorylated derivates, facilitating the selective and systematic functionalization of the fluorenyl system. All compounds were stable up to ca. 350 degrees C, except for a sterically crowded branched derivative. The linear optical properties of the compounds were investigated by UV-visible, steady-state fluorescence, and excitation anisotropy spectroscopic measurements. Fluorescence quantum yields were greater than or equal to 0.84 for symmetric linear and unsymmetric branched derivatives. Very high two-photon absorption (2PA) cross-sections were achieved (5765 GM at 520 nm and 4194 GM at 570 nm), as determined with use of picosecond and femtosecond laser excitation sources, respectively.

Journal Article↗
PubMed2005

Two-dimensional self-assembly into multicomponent hydrogen-bonded nanostructures.

By means of scanning tunneling microscopy, we have explored the two-dimensional self-assembly of functional bicomponent hydrogen-bonding dye systems, leading to well-defined patterns, different from those of the individual components, and providing design rules to immobilize multicomponent systems at the liquid-solid interface.

Journal Article↗
PubMed2005

[Evaluation of rigid internal fixation in mandibular reconstruction with autogenous bone].

OBJECTIVE: To investigate the application of rigid internal fixation in mandibular reconstruction with autogenous bone and to evaluate its efficacy. METHODS: From January 1994 to May 2004, 98 patients with mandibular defect received mandibular reconstruction with autogenous bone by using rigid internal fixation. Seventy-two cases of benign tumor and 26 cases of malignant tumor were included. Four hundred and ono rigid fixation plates were inserted. The clinical results and X-ray films were analyzed and the healing processes were evaluated. The functional and aesthetic results of the mandibular reconstruction were also evaluated according to Lopez assessment system. RESULTS: After a follow-up of 1 to 3 years, 95 patients (96.9%)achieved successful effect. The forms and function of the mandibles were resumed. Eighty-one (82.7%) patients were satisfied with the results of operations. Thirteen patients (13.3%) achieved acceptable results. Four patients (4.1%) were dissatisfied with the results of operations. CONCLUSION: The rigid internal fixation is conductive to healing and remodeling of the transplant bone in mandibular reconstruction.

Adolescent↗
PubMed2004

Supramolecular polymerization and gel formation of bis(merocyanine) dyes driven by dipolar aggregation.

Two highly dipolar merocyanine dyes were tethered by a rigid tris(n-dodecyloxy)xylylene unit that preorganizes the dyes for a supramolecular polymerization process through intermolecular aggregation of the dyes. UV/vis spectroscopy revealed a solvent dependent equilibrium between monomeric dyes and two different types of dye aggregates that are characterized by hypsochromically shifted D- and H-type absorption bands. Taking into account the ditopic nature of the supramolecular building blocks, the occurrence of the D-band indicates the formation of an oligomeric/polymeric supramolecular chain whereas the observation of the H-band suggests a higher order assembly. For the H-aggregated dyes, intrinsic viscosities exceed 0.65 L g(-1) in methylcyclohexane, values typically found for macromolecular solutions. At higher concentration, further association of these aggregates takes place by entanglement of the alkyl groups leading to a substantial increase in viscosity and gelation. Rheology studies show linear viscoelastic behavior which was attributed to the formation of an entangled dynamic network. AFM and cryo-TEM studies of the gel reveal long and stiff rod-type assemblies. X-ray diffraction studies for a solid film show columnar mesomorphism. Based on these results, a structural model is proposed in which six helically preorganized strands of the supramolecular polymer intertwine to form a rod with a diameter of about 5 nm. Within these rods all dyes are tightly aggregated in a tubular fashion giving rise to delocalized excitonic states, and the pi-conjugated tube is jacketed by the tridodecyloxy groups.

Coloring Agents↗
PubMed2004

[Effects of extracellular signal-regulated kinase inhibition by AG126 on tissue tumor necrosis factor-alpha expression and multiple organ dysfunction in rats with postburn Staphylococcus aureus sepsis].

OBJECTIVE: To investigate the effects of extracellular signal-regulated kinase (ERKs) inhibition by AG126 on tissue tumor necrosis factor-alpha (TNF-alpha) expression and multiple organ dysfunction in rats with postburn Staphylococcus aureus sepsis and its potential signal regulating mechanism. METHODS: To reproduce postburn sepsis model, male Wistar rats were inflicated with 20% total body surface area third-degree scald followed by Staphylococcus aureus challenge. 34 rats were randomly divided into four groups as follows: normal control group (n = 6), scald control group (n = 6), postburn sepsis group (n = 12), and AG126 treatment group (n = 10). Tissue samples from the liver, kidneys and lungs were collected to determine phosphorylated ERKs by Western blot analysis, and TNF-alpha mRNA expression as well as its protein levels. RESULTS: It was revealed that phosphorylated ERKs in the liver, lungs, and kidneys from postburn septic animals were up-regulated rapidly at 0.5 - 2.0 hours, being 1.94-fold (P < 0.05), 2.86-fold (P < 0.01), and 1.41-fold at 2.0 hours compared to normal controls, respectively. Treatment with AG126 could significantly reduce phosphorylated ERKs in lung tissue by 70.6% (P < 0.01) at 2.0 hours postburn sepsis, and almost completely inhibited ERKs activation in the liver and kidneys at various time points. Meanwhile, both TNF-alpha mRNA and protein expressions in the liver, lungs, and kidneys were significantly decreased in AG126-treated group following septic challenge (P < 0.05 or 0.01). In addition, 2.0 hours after Staphylococcus aureus infection, treatment with AG126 markedly improved hepatic and renal function parameters, including serum ALT, AST, Cr, as well as BUN levels (P < 0.05 or 0.01), together with significant decrease in pulmonary myeloperoxidase activity, compared to those without AG126 treatment. CONCLUSION: These data suggested that ERKs signal transduction might be involved in the pathogenesis of systemic inflammatory response and multiple organ dysfunction in postburn gram-positive bacterial sepsis. Early treatment with AG126 could significantly down-regulate TNF-alpha mRNA expression as well as protein levels in vital organs and attenuate multiple organ dysfunction induced by scald injury combined with Staphylococcus aureus challenge.

Animals↗
PubMed2004

[Clinical features in 4 Chinese families with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)].

OBJECTIVE: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is an inherited cerebral arteriolar disease in adulthood, which is caused by NOTCH3 gene mutation. The main symptoms were migraine, cerebral stroke, later with mood disorders and dementia in Caucasian patients. Recently, the disease was also recognized in Asian patients, in whom the migraine is rarely reported. In order to give the clinical features of Chinese patients, we described the clinical symptoms in 4 CADASIL families. METHODS: CADASIL was diagnosed by the investigation of ultra-structure changes of arteriole in sural nerve and NOTCH3 gene mutation in the 4 index cases. Detailed clinical and routine laboratory examinations were performed in these 4 patients, including electrocardiography, nerve conduction velocity, serum glycogen, and serum homocysteine. Additionally, we also collected the clinical data of the other 83 family members through interviews and the available medical records. RESULTS: Of the 83 persons, 29 were classified as clinical suspected patients, who presented one or more of the disease-related neurological symptoms, such as cerebral ischemic events and the cognitive impairment. All of them showed no common risk factors for stroke, such as diabetic mellitus, hypertension, and heart disease. The clinical suspected patients distributed in every consecutive generations and involved both sexes, which was according to the autosomal dominant inherited pattern. The onset age of the disease ranged from 28 to 70-year-old and mainly between the 4th and the 5th decades. The main symptoms were recurrent episodic vertigo, with or without hemiplegia. At the same time or a little bit later, the cognitive impairment was developed in some patients. Compared with the typical presentations of the disease in European patients, none of our 29 patients showed migraine,one index case showed mild sensory disturbance in extremities. Elevated serum homocysteine level and abnormal of nerve conduction study in two index cases (3 and 4) were noticed. CONCLUSION: The onset age of the disease of our patients is similar to that of Caucasian patients. The main symptoms were stroke and dementia. Involvement of post circulation system was the main clinical feature for ischemic events in our patients. Dementia could be found in the early stage of disease. Migraine should not be regarded as a common clinical feature in our patients. The involvement of the peripheral nerves expanded the disease expression outside the central nervous system.

Adult↗
PubMed2003

Merocyanine dyes containing imide functional groups: synthesis and studies on hydrogen bonding to melamine receptors.

The condensation of the CH acidic heterocycles 4-alkyl-2,6-dioxo-1,2,5,6-tetrahydropyridine-3-carbonitrile (5a and b) and barbituric acid (15) with electron-rich thiophene aldehydes and benzaldehyde derivatives affords the respective monomethine dyes 10-13 and 17-19. The formylation of 5a,b and 15 with N,N'-diphenylformamidine or dibutylformamide in acetic anhydride and further reaction with 4-picolinium salts 9a,b provide the dimethine dyes 14 and 20a,b. Triple hydrogen bonding of the imide groups of merocyanine dyes 10-14 has been investigated by NMR titration experiments with melamine 21. Despite rather pronounced variations of the charge-transfer properties within the given series of dyes, minor changes of their binding constants have been observed. These results could be rationalized by semiempirical calculations that reveal small changes in the charge density at the oxygen functionalities involved in hydrogen bonding upon variation of the electron-donating carbocyclic or heterocyclic groups at the terminal double bond. Although the binding constants for triple hydrogen bonding between imides and melamines are rather weak in chloroform, they proved to be strong enough to facilitate dissolution of some of these dyes in aliphatic solvents by coordination to amphiphilic melamines and dipolar aggregation. UV-vis spectral changes observed in methylcyclohexane vs chloroform suggest the formation of colloidal assemblies through noncovalent polymerization.

Hydrogen Bonding↗