Concurrent Ammonia Synthesis and Alcohol Oxidation Boosted by Glutathione-Capped Quantum Dots under Visible Light.

Mother nature accomplishes efficient ammonia synthesis via cascade N2 oxidation by lightning strikes followed with enzyme-catalyzed nitrogen oxyanion (NOx -, x = 2,3) reduction. The protein environment of enzymatic centers for NOx --to-NH4 + process greatly inspires the design of glutathione-capped (GSH) quantum dots (QDs) for ammonia synthesis under visible light (440 nm) in tandem with plasma-enabled N2 oxidation. Mechanistic studies reveal that GSH induces positive shift of surface charge to strengthen the interaction between NOx - and QDs. Upon visible light irradiation of QDs, the balanced and rapid hole and electron transfer furnish GS·radicals for 2e-/2H+ alcohol oxidation and H·for 8e-/10H+ NO3 --to-NH4 + reduction simultaneously. For the first time, mmol-scale ammonia synthesis is realized with apparent quantum yields of 5.45% ± 0.64%, and gram-scale synthesis of value-added acetophenone and NH4Cl proceeds with 1:4 stoichiometry and stability, demonstrating promising multielectron and multiproton ammonia synthesis efficiency and sustainability with nature-inspired artificial photocatalysts.

Luminescent carbon dots with concentration-dependent emission in solution and yellow emission in solid state.

Carbon dots (CDs) is a class of zero-dimensional carbon nanomaterials with favorable stability and optical properties. However, CDs in solid state often suffer from fluorescence quenching due to π-π stacking of conjugated systems, like most small molecules or organic dyes. Herein, we prepared the CDs that generate bright yellow luminescence in solid state without any additional matrix, meanwhile the solid CDs are inclined to assembly into spherical structure. While the CDs are dissolved in aqueous solution, the photoluminescence (PL) emission from blue to green can be realized by regulating the concentration of CDs. With the concentration increasing, the self-assembly behavior of CDs is observed in solution, which leads to the bathochromic shift of photoluminescence. Besides, the mechanism of PL conversion in this process was proposed based on the characterization results, that with the concentration of CDs rising in solution, π-π interaction was restrained while electron redistribution was induced. Consequently, a localized state II caused by electron rearrangement gradually becomes the predominant emission state, resulting in the PL emission shifting to long-wavelength region. Moreover, CDs have shown favorable potentials in the field of anti-counterfeit and multicolor bioimaging, making the CDs highly attractive for a wide variety of applications.

Role of surface charge on the interaction between carbon nanodots and human serum albumin.

Carbon nanodots (Cdots) have aroused widespread concerns in the field of biomedical applications. In order to achieve better implications of behavior of Cdots in the biological environment, an array of spectroscopic, electrochemical and calorimetric techniques were performed to study the interaction of Cdots possessing different charges with human serum albumin (HSA) in physiological condition. Two polymer, polyethylene glycol (PEG) and polyetherimide (PEI), were applied to passivate the bare Cdots to achieve the Cdots with different surface charge, namely negatively charged PEG Cdots and positively charged PEI Cdots. The fluorescence of HSA was obviously quenched by both Cdots in a charge-independent behavior through a dynamic collision mechanism. Moreover, the association affinity of PEG Cdots or PEI Cdots bound to HSA was very close to each other. In addition, PEG Cdots with diverse content exhibited little effects on the secondary structure of HSA while only high content of PEI Cdots induced obvious conformation perturbation of HSA. The electrostatic forces dominate the association between HSA and PEI Cdots while the association of PEG Cdots to HSA is initiated by hydrophobic and van der Waals forces. Furthermore, the results of isothermal titration calorimetry revealed that both the interaction was driven by favorable entropy and enthalpy, which confirmed that these association processes are thermodynamically spontaneous. Finally, the sites marker competitive experiment showed that the association sites of Cdots with HSA exhibit a charge dependent manner, namely PEG Cdots effectively occupy the site I of HSA while the association sites of PEI Cdots are mainly located in site II.

[Clinical analysis of 40 cases with sinonasal adenoid cystic carcinoma].

OBJECTIVE: To study the clinical characters and the mode of treatment, and to analyze the prognosis of patients with sinonasal adenoid cystic carcinoma. METHODS: The clinical data were analyzed retrospectively in 40 patients with sinonasal adenoid cystic carcinoma. The characters of survival rate, local recurrence and distant metastasis in these patients were analyzed using Kaplan-Meier method and Log-rank test. RESULTS: The maxillary sinus was the most common site of origin and account for 80% of all patients. Five-year and ten-year overall survival rate were 76.9% and 61.6% respectively. Five-year and ten-year disease-free survival rate were 44.2% and 23.0%. Five-year local recurrence rate and distant metastasis rate were 45.0% and 23.0%, respectively. The most common site of distant metastasis was lung. Presence of distant metastasis correlated with decreased 5-year survival (chi2=7.26, P=0.007). The distant metastasis rate of preoperative treatment (18.2%) seemed lower than that of postoperative treatment (38.9%), but there was no significant difference in the two groups (chi2=1.37, P=0.24). The combined therapy mainly composed of surgery was adopted to treat the local recurrence. Five-year survival rate after development of local recurrence was 60.0%. CONCLUSIONS: Distant metastasis is an important factor affecting the prognosis of the patients with sinonasal adenoid cystic carcinoma. Combined therapy composed of surgery and radiation was the first choice of treatment to the patients with sinonasal adenoid cystic carcinoma. Radiation can play an important role in the treatment. The combined therapy mainly composed of surgery should be adopted in the patients with local recurrence to improve the survival rate.

[Esophageal voice training and quality of life in laryngectomees].

OBJECTIVE: To evaluate the extensive and degree of physical rehabilitation improvement of the quality of life in laryngectomees. METHODS: Forty nine patients who underwent total laryngectomies were trained by esophageal voice rehabilitation successfully. The questionnaires of performance status scale for head and neck cancer patients (PSS-HN) and the functional assessment of head and neck cancer therapy (FACT-H&N) were answered by them before esophageal voice training and 3 months after successful vocal rehabilitation. RESULTS: Total laryngectomy deteriorated the quality of life in laryngectomees. The mean scores of PSS-HN scale and FACT-H&N questionnaire were lower than the criteria scores after patients underwent total laryngectomy, the mean score were 131. 4,90.6 respectively, the difference was significant statistically (t =53. 673, P <0.001) , (t = 67.44, P <0.001). After successful esophageal speech training, the mean scores of the laryngectomees were improved both in PSS-HN scale and FACT-H&N which were 240.4 and 103.7 respectively, the difference was significant statistically (t = 18.209, P < 0.001) , (t = 21.389, P<0.001). CONCLUSIONS: The quality of life in laryngectomees can be improved by physical rehabilitation and the esophageal voice training.

[Evaluation of sentinel lymph node in squamous cell carcinoma of the head and neck].

OBJECTIVE: To assess the feasibility of sentinel lymph node (SLN) radiolocalization in stage in head and neck squamous cell carcinoma and to gain insight as to whether the sentinel lymph node could be prognostic of regional micrometastatic disease. METHODS: A prospective trial was made on the application sentinel lymph node radiolocalization in 10 patients with NO squamous cell carcinoma of the head and neck region. For each patient a peritumoral submucosal injection of filtered technetium 99m prepared with dextran colloid (99mTc-DX) was performed immediately. After 30 minutes, focal areas of accumulation corresponding to sentinel lymph nodes (SLN) were marked on the skin surface. The SLN was localized by lymphoscintigraphy and intraoperatively through the intact skin by a hand-held gamma-probe. SLN was defined as the count of lymph node could be detected 4 times more than that of background. Complete neck dissections were performed, and SLNs were identified for later histological evaluation and comparison to the remaining lymphadenectomy specimen. RESULTS: SLN radiolocalization accurately identified one or more SLNs in the ten cases. 3 of 10 cases revealed occult metastatic disease. Therefore the negative metastasis rate was 30% (3/10). The positive rate of SLN and nonsentinel lymph node (NSLN) were 22.7% (5/22) and 0.4% (1/247) respectively. Serial sectioning (SS) and immunohistochemical (IHC) on SLNs would reduce the false-negative rate of sentinel lymph node biopsy (SLNB). There was no instance in which SLN was negative for micrometastatic disease while being positive in a nonsentinel lymph node. CONCLUSIONS: SLN evaluation in NO neck in squamous cell carcinoma of the head and neck is accurately feasible and seems to adequately predict the presence of occult metastasis. Although SLN radiolocalization in head and neck squamous cell carcinoma may potentially reduce the time, cost, and morbidity of regional lymph node management, more experience with technique is required before its role can be determined.