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Biomedical subjects

Chun Huang

Publications and source records attributed to Chun Huang.

16 recordsLinked to original sources

Engineering B cells to Express Fully Customizable Antibodies with Enhanced Fc Functions.

Genome editing within the constant region of the immunoglobulin Heavy chain locus (IGH) can reprogram B cells to express Heavy chain only antibodies (HCAbs) containing custom antigen-recognition domains. HCAb-engineered cells express both surface B cell receptor (BCR) and secreted antibody isoforms and respond to antigen. By selecting alternate editing sites within IGH, we extended this approach to also allow customization of the constant (Fc) domain of the Heavy chain, producing HCAbs with enhanced effector functions or containing mutations to extend antibody half-life. We also introduced mutations to force obligate HCAb homodimers and prevent unwanted pairing with endogenous antibody chains. Finally, we showed that additional domains could be accommodated at the HCAb C-terminus and preferentially expressed in the secreted isoform. Together these data demonstrate the flexibility of the HCAb editing platform to express fully customized molecules that take advantage of the properties of B cells.

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Tuning the hole injection barrier at the organic/metal interface with self-assembled functionalized aromatic thiols.

Self-assembled functionalized aromatic thiols (oligophenylenes composed of building blocks of dimethoxy-substituted phenylenes, perfluoro-substituted phenylenes, and a terminal thiol group) were used to tune the hole injection barrier (Delta(h)) of copper(II) phthalocyanine (CuPc) on Au(111). Synchrotron-based high-resolution photoemission spectroscopy study reveals a significant reduction of Delta(h) by as much as 0.75 eV from Delta(h) = 0.9 eV for CuPc/Au(111) to Delta(h) = 0.15 eV for CuPc/BOF/Au(111), where BOF represents 4-pentafluorophenyl-1-(p-thiophenyl)-2,5-dimethoxybenzene. The delocalized pi orbitals of these functionalized aromatic thiols greatly facilitate effective charge transfer (hole or electron) across the SAM interface as compared to alkanethiols, hence making this novel interface modification scheme a simple and effective way to tune the hole injection barrier. This method has potential applications in molecular electronics, organic light-emitting diodes (OLED), organic field-effect transistors (OFETs), and organic solar cells.

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Direct adsorption and monolayer self-assembly of acetyl-protected dithiols.

The alpha,omega-dithiols, with sulfur-containing groups at both ends of the molecules, can be used to bridge a metallic gap. Functional self-assembled monolayers (SAMs) of these dithiols must "stand up" on the surface and expose one thiol group for further reaction. However, both parallel and upright surface orientations and multilayer formation can occur for alpha,omega-dithiols. We find SAMs deposited directly from acetyl protected dithiols (i.e., with no de-protection step) overcome these problems. We present a systematic study of adsorption kinetics from in situ surface plasmon resonance spectroscopy, X-ray photoelectron spectroscopy, and secondary ion mass spectroscopy of alkane- and oligo(phenylene ethylnylene)-based alpha,omega-dithioacetates on gold.

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Effect of functional group (fluorine) of aromatic thiols on electron transfer at the molecule-metal interface.

Electron transfer at the molecule-metal interface of self-assembled monolayers of 1,1';4',1''-terphenyl-4''-thiol (BBB) and its partially fluorinated counterpart (BFF: p-thiophenyl-nonafluorobiphenyl) on Au(111) is investigated by core-hole clock spectroscopy. Ultrafast electron transfer at the BBB/Au(111) interface in the low-femtosecond regime (on the same time scale as the C 1s core-hole lifetime, approximately 6 fs) was observed. In contrast, for BFF/Au(111), the interface electron transfer was forbidden during the core-hole decay. This strongly suggests that fluorination of phenyl rings significantly enhances the localization of the excited electrons in the LUMO.

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Ultrafast electron transfer from oligo(p-phenylene-ethynylene)thiol to gold.

The electron transfer dynamics of oligo(p-phenylene-ethynylene) (OPE) SAM on Au(111) was studied by resonant photoemission spectroscopy. The ultrafast electron transfer from OPE molecules to Au substrate was clearly observed. The time scale for this charge transfer is much less than 6 fs, the core-hole lifetime for C 1s. This strongly suggests that there is an intense interfacial electronic coupling between OPE molecules and the Au substrate.

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Solution-processable polyphenylphenyl dendron bearing molecules for highly efficient blue light-emitting diodes.

[structure: see text] Novel solution-processable blue light-emitting materials Blue A-D, bearing a polyphenylphenyl dendron, have been synthesized and characterized. The energy levels and band gaps can be facilely tuned by changing the central aromatic ring of the molecules. A highly efficient deep blue light-emitting OLED device based on Blue C with a maximum current efficiency of 2.2 cd/A has been achieved using PVK as the host material through a solution process.

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[Psychological and physical presentations of severe acute respiratory syndrome].

OBJECTIVE: To study the relation between psychological symptoms and physical parameters in patients with severe acute respiratory syndrome (SARS) at different stages of the disease. METHODS: Physical parameters such as SCL-90, chest CT, T lymphocytes and subset and SaO2 were studied in 29 SARS patients at three different stages (initial stage, serious stage, rehabilitating stage). RESULTS: Patients with SARS showing severe psychological symptoms constituted about 41% (group I) and patients with SARS showing mild psychological symptoms (group II) constituted about 59%. There were no change of the psychological symptoms at the three stages in group I and II (P > 0.05). Statistical differences were found between physical parameters of group I and II in rehabilitating stage. CONCLUSIONS: Severe psychological symptoms such as obsession, depression and anxiety were found in a minority of patients with SARS and the psychological symptoms were not related with the change of physical parameters. The majority of the patients with SARS did not have severe psychological symptoms. Whether or not psychological symptoms were related to their personality needs further study.

Adolescent↗

Surface modification studies of edge-oriented molybdenum sulfide nanosheets.

We have synthesized edge-oriented MoS2 nanosheets by the evaporation of a single source precursor based on Mo(IV)-tetrakis(diethylaminodithiocarbomato). The surface chemistry of the MoS2 nanosheets has been studied in order to evaluate the chemical reactivities of the basal planes and edges. By irradiating the MoS2 nanosheet with a scanning infrared laser, micron-scale lithographical structures can be created due to laser-induced oxidation of MoS2 to form nanocrystalline MoO3. Preferential reactivities of the MoS2 basal edges in an electrochemical environment and during vapor phase deposition have been demonstrated. Functionalization of the basal plane with 1-pyrene acetic acid allows the immobilization of DNA and immunoglobins on the MoS2 basal plane.

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Evaluation of effect of hybrid bioartificial liver using end-stage liver disease model.

AIM: To study the role of hybrid bioartificial liver (HBL) in clearing proinflammatory cytokines and endotoxin in patients with acute and sub-acute liver failure and the effects of HBL on systemic inflammatory syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). METHODS: Five cases with severe liver failure (3 acute and 2 subacute) were treated with HBL. The clinical signs and symptoms, total bilirubin (TBIL), serum ammonia, endotoxin TNF-alpha, IL-6 and prothrombin activity (PTA),cholinesterase (CHE) were recorded before, during and after treatment. The end-stage liver disease (MELD) was used for the study. RESULTS: Two patients were bridged for spontaneous recovery and 1 patient was bridged for OLT successfully. Another 2 patients died on d 8 and d 21. The spontaneous recovery rate was 30.0%. PTA and CHE in all patients were significantly increased (P<0.01), while the serum TBIL, endotoxin, TNF-alpha, IL-6 were decreased. MELD score (mean 43.6) predicted 100% deaths within 3 mo before treatment with HBL. After treatment with HBL, four out of 5 patients had decreased MELD scores (mean 36.6). The MELD score predicted 66% mortalities. CONCLUSION: The proinflammatory cytokines (TNFalpha, IL-6 and endotoxin)can be significantly removed by hybrid bioartificial liver and HBL appears to be effective in blocking SIRS and MODS in patients with acute and sub-acute liver failure. MELD is a reliable measure for predicting short-term mortality risk in patients with end-stage liver disease. The prognostic result also corresponds to clinical outcome.

Adult↗

Ginsenoside Rg1 attenuates dopamine-induced apoptosis in PC12 cells by suppressing oxidative stress.

In Parkinson's disease, neuroprotective therapy to rescue dopamine neurons has been proposed. Ginsenoside Rg1, one of the biologically active ingredients of ginseng, may be a candidate neuroprotective drug. In the present study, the mechanism underlying the neuroprotection provided by ginsenosde Rg1 was studied against apoptosis induced by exogenous dopamine in PC12 cells. Pretreatment with ginsenoside Rg1 markedly reduced the generation of dopamine-induced reactive oxygen species and the release of mitochondrial cytochrome c into the cytosol, and subsequently inhibited the activation of caspase-3. In addition, Rg1 pretreatment also reduced inducible nitric oxide (NO) synthase protein level and NO production. These results suggested that ginsenoside Rg1 may attenuate dopamine-induced apoptotic cell death through suppression of intracellular oxidative stress, and that it may rescue or protect dopamine neurons in Parkinson's disease.

Animals↗

[Clinical manifestation, treatment, and outcome of severe acute respiratory syndrome: analysis of 108 cases in Beijing].

OBJECTIVE: To investigate the clinical manifestations, treatment, and outcome of severe acute respiratory syndrome (SARS). METHODS: The clinical data of 108 SARS in-patients were analyzed. RESULTS: Among the 108 cases, 35 males (32.4%) and 73 females (67.6%), aged 37 +/- 9 (range 13 approximately 83 years), most were white-collar workers, medical workers accounting for 28.7%. 87.0% had a definite contact history. 20.4% were complicated by other internal diseases. The main clinical manifestations included fever, cough, pectoralgia, chest distress, headache, etc. Involvement of multiple organs was often. The incubation period was 2 approximately 14 days. The course included early stage, progressive stage, climax, and convalescence. Mild type accounted for 4.6%, common type 39.8%, severe type 20.4%, and extremely severe type 35.2%. At the early stage, white blood cell count, lymphocyte count and ratio of lymphocyte, proalbumin, transferring, CD(3)(+), CD(4)(+), CD(8)(+) cell count were remarkably decreased, and C-reactive protein, alpha-acid glycoprotein, and alpha(2)-globulin were remarkably increased. X-ray chest film showed solitary or multiple local exudative changes, mostly in pulmonary lower field. During the progressive stage the hyaline or consolidation images were enlarged. High solution CT showed solitary or multiple cotton wadding like images and ground glass-like or consolidation images. Hypoxemia was common. At the progressive stage application of adrenocortical hormones and non-invasive mechanical ventilation helped stop the progress of disease. Ninety-four cases were discharged, 14 cases died. Traditional Chinese medicine (TCM) regards SARS as one of epidemic febrile diseases. Treatment by combination of TCM and Western medicine was effective. CONCLUSION: SARS mainly affects youth and people in their prime of life. It has its own characteristic clinical manifestations. The classification system of 5 types and 4 stages helps judge the condition. Treatment by combination of TCM and Western medicine is encouraged.

Adolescent↗

[Clinical features of severe acute respiratory syndrome in forty-one confirmed health care workers].

OBJECTIVE: To investigate the clinical features of severe acute respiratory syndrome (SARS). METHODS: Forty-one medical care workers (aged 23 - 55 years, with a average of 32 years; men/women = 8/32) who were admitted to our hospital and diagnosed with SARS during March and April, 2003 were retrospectively analyzed. RESULTS: Thirteen of all the patients were physicians and the rest were nurses. The disease was mainly transmitted through air droplet in a short distance, and overwork induced tiredness was involved in disease stimulation. Seventy-three percent of the patients presented fever as their first symptom. Ten patients complained inertia and myalgia. One patient showed no clinical symptoms, and bilateral infiltrates was found in his chest X-ray. Among the 41 cases, 6 (15%) were diagnosed as severe type. At the first week, the counts of white blood cells (WBCs), lymphocyte and platelets were (4.4 +/- 1.5) x 10(9)/L, 0.22 +/- 0.12 and (143 +/- 37) x 10(9)/L, which were significantly lower when compared with those at the 2nd to 4th week. Abnormal liver function was found in 27 cases (mostly with elevated serum ALT), with 70% occurred at the 3rd or 4th week. In terms of CT, 30 patients (73%) showed pathological changes in lungs, and bilateral lung involvement was found in 35.59%. Of 36 cases treated with steroids, 86% received middle or low dosage (80 - 240 mg/d). Artificial ventilation was used for twenty-seven patients, and air pipe mechanical ventilation was used for 1 case. Mortality in this study was 5%. CONCLUSIONS: Inertia and myalgia may be the earlier symptoms of health care workers with SARS include, which are parallel to CT manifestations. There is no objective index for the assessment of the severity of the disease at early stage. The medicine associated toxicities may be the main reason of liver lesions. damages. Middle or low dosage of steroid was reasonable to be used as early as possible.

Adult↗

[Pathologic grading and clinical features of chronic hepatitis B].

OBJECTIVE: To raise the accuracy of clinical diagnosis of chronic hepatitis B. METHODS: The correlation between the clinical features, biochemical tests (the serum total bilirubin-TBil, albumin-ALB, prothrobin activity-PTA, alanine aminotransferase-ALT, albumin/globulin-A/G, and r-globulin-r-G) and histopathological data in 202 patients with chronic hepatitis B (CHB) were studied. RESULTS: Some of presenting symptoms and signs were obviously associated with histological grade and stage. The grade of necroinflammatory activity of CHB was associated with the rising TBil, ALT, GGT and the declining ALB, A/G and PTA. The coincidence of clinical diagnosis and pathology was highest in mild chronic hepatitis, 63.8%~79.0%; then was in marked chronic hepatitis, 40.0%~62.5%. The coincidence was lowest in moderate chronic hepatitis, 10.0%~28.2%. CONCLUSIONS: Great attention should be paid to the significance of symptoms and signs, meanwhile the standard of clinical diagnosis for moderate chronic hepatitis might be relaxed somewhat.

Adolescent↗

[The analysis of medical-related cost for in-patients with injuries in Ningxia region].

OBJECTIVE: To understand socio-economic losses of inpatients and deaths caused by injuries in 2000 in Ningxia and to estimate their extent of harmfulness. METHODS: Eight of 35 local hospitals totaling 5 876 inpatients were recruited with two-stage sampling in Ningxia in 2000. All medical cost incurred during their hospitalizations for injuries, cardiovascular and cerebrovascular diseases, respiratory disease, cancer and communicable diseases, losses in labor time were analyzed, and years of potential life lost (YPLL), working years of potential lost (WYPLL), valued years of potential life lost (VYPLL) due to these diseases were estimated for the residents in Ningxia with corrected human capital method. RESULTS: The study showed that indirect economic losses due to hospitalization for injuries accounted for 24 million yuan, higher than those for other diseases. YPLL, WYPLL and VYPLL due to injuries were also higher than those in other diseases. CONCLUSIONS: Injury has caused serious threat to their health of the residents in Ningxia and brought heavy burden for the society and economy. It has become an important public health problem and its prevention and control should be strengthened as soon as possible.

Adolescent↗

[Clinical analysis of 80 perinatal death from hepatic diseases in pregnancy].

OBJECTIVE: To explore the factors associated with perinatal death of hepatic diseases in pregnancy (HDIP) and make feasible suggestions and measures for perinatal care of high risk patients. METHODS: The 80 perinatal death cases of hepatic diseases in pregnancy (HDIP) during 1991-2000 in our hospital were analyzed retrospectively. RESULTS: The perinatal mortality of HDIP in our hospital during the last 10 years was 17.99 approximately 65% was in utero death. Perinatal mortality was different between male (21.64%) and female (10.11%) (P<0.01). Compared first 5 years with last 5 years author found that the perinatal mortality of HDIP had no significant decrease (P>0.05). The perinatal mortality in city and suburbs had decreased, while in the floating population from other provinces the perinatal mortality had increased. The perinatal death was mainly caused by pregnancy induced hypertension (PIH) and asphyxia. But for the HBV carrier mothers the causes of death included umbilical cord problems, premature rupture of membrane and asphyxia. CONCLUSIONS: The perinatal death mortality was increased by HDIP, deaths were essentially associated with pregnancy induced hypertension and asphyxia and the floating population and male gender were high risks. To enhance the management of HDIP or immigration, take effective therapies of hepatitis and improvement of resuscitation of newborns are critically important.

Adolescent↗