Multi-walled carbon nanotubes as a new counter electrode for dye-sensitized solar cells.

Airbrushed multi-walled carbon nanotube (MWNT) networks were investigated as a new counter electrode for dye-sensitized TiO2 photoelectrochemical solar cells. The structural and physical properties of the MWNTs were studied by various techniques including SEM, TEM, Raman, optical absorption, and electrochemical impedance spectroscopy (EIS). The MWNTs exhibited catalytic activity for the reduction of triiodide in the electrolyte as studied by EIS measurements. The performance of the dye-sensitized solar cells was improved by using MWNTs as counter electrodes. This observation is explained by the significantly increased contact area between the MWNT counter electrode and the electrolyte which facilitates efficient charge transportation in the solar cell. We demonstrated that the MWNTs are suitable for replacing expensive Pt electrodes for fabricating high efficiency dye-sensitized solar cells. The process used in this study is also technically attractive for large scale and economic production.

Risk factors for early-onset ventilator-associated pneumonia in aneurysmal subarachnoid hemorrhage patients.

This study aimed to investigate the risk factors related to ventilator-acquired pneumonia (VAP) in aneurysmal subarachnoid hemorrhage (SAH) patients. From January 2011 to December 2015, a single-center retrospective study including 200 SAH patients requiring mechanical ventilation (MV) ≥48 h was performed. The clinical data of these patients were collected and analyzed. The age range of the patients were 41-63 and 72 (36%) were male. The Glasgow coma scale score range was 5-15 and the Simplified Acute Physiology Score II range was 31-52. One hundred and forty-eight (74%) patients had a World Federation of Neurosurgeons (WNFS) score ≥III. Aneurysm was secured with an endovascular coiling procedure in 168 (84%) patients and 94 (47%) patients presented VAP. Male gender (OR=2.25, 95%CI=1.15-4.45), use of mannitol (OR=3.02, 95%CI=1.53-5.94) and enteral feeding above 20 kcal·kg-1·day-1 (OR=2.90, 95%CI=1.26-6.67) after day 7 were independent factors for VAP. Patients with early-onset VAP had a longer duration of sedation (P=0.03), MV (P=0.001) and ICU length of stay (P=0.003) and a worse Glasgow Outcome Scale score (P<0.001), but did not have a higher death rate.

Clinical diagnosis of cerebral vasospasm after subarachnoid hemorrhage by using transcranial Doppler sonography.

OBJECTIVE: To investigate the diagnosis of cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) by transcranial Doppler (TCD) sonography. PATIENTS AND METHODS: 90 patients with SAH admitted to the Department of Neurosurgery of Weifang People's Hospital from January 2016 to December 2016 were selected. TCD and digital subtraction angiography (DSA) were used to diagnose the prevalence of CVS in patients. The severity of disease was evaluated (improved-Fisher grading). Correlations between neurological status (Hunt-Hess grading) and the prevalence of CVS were analyzed. It turned out that the prevalence of CVS was 87.78% detected by DSA and was 83.33% detected by TCD, no significant difference was found between them (p > 0.05). RESULTS: The results of TCD showed that the gender, age, smoking, alcoholism, and history of hypertension had no significant correlations with the prevalence of CVS (p > 0.05). Blood flow velocity of patients was significantly higher at 4-6 days after the occurrence of SAH compared with the level at 1-3 days, reached the peak at 7-9 days, and decreased at 10-12 days after occurrence. Significant differences in the severity of the disease were found between patients with different improved-Fisher grades and different Hunt-Hess grades (p < 0.05). The prevalence of CVS was significantly increased after SAH (p < 0.05). CONCLUSIONS: TCD can dynamically detect the blood flow velocity of SAH patients, and can be used for the prediction and diagnosis of CVS after SAH.

Expression of Nrf2-Keap1-ARE signal pathway in traumatic lung injury and functional study.

OBJECTIVE: Traumatic lung injury (TLI) can cause inflammation and oxidative stress, or even leads to acute respiratory distress syndrome (ARDS) and death. Nuclear factor erythroid-2 related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1)-antioxidant response element (ARE) signal pathway participates in disease occurrence and progression via regulating inflammatory and oxidative stress response, but with its expression and functional roles in TLI largely unknown. MATERIALS AND METHODS: Wistar rats were randomly divided into control group, TLI group by crushing method, and Nrf2 activation group which received Nrf2 specific agonist sulforaphane 30 min before TLI treatment. Artery blood gas (ABG), wet/dry mass ratio (W/D) of lung tissues, myeloid peroxidase (MPO) and superoxide dismutase (SOD) activity of lung tissue were analyzed. Keap1 and ARE mRNA levels were tested by Real-time PCR, while Nrf2 protein was measured by Western blot. Inflammatory factors including tumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) were quantified by enzyme-linked immunosorbent assay (ELISA). RESULTS: TLI model had lower ABG or SOD, higher W/D ratio, MPO value, elevated expressions of TNF-α, IL-2, and Keap1, plus decreased Nrf2 and ARE expression (p<0.05). Nrf2 activation significantly improved ABG, decreased W/D ratio and MPO value, enhanced SOD activity, decreased TNF-α and IL-2 secretion, suppressed Keap1 expression, and facilitated Nrf2 and ARE expressions (p<0.05). CONCLUSIONS: Nrf2-Keap1-ARE signal pathway can improve TLI-related pathology via modulating oxidative stress response and suppressing inflammation.

[Studies on HPLC method for determination of 4-methylaminoantipyrine and relative bioavailabilities of analgin nasal drops in human volunteers].

A new HPLC method for the determination of a metabolite of analgin, MAA (4-methylaminoantipyrine), in plasma and its application to determine the bioavailabilities of analgin nasal drops in human volunteers is reported in this paper. A Waters Model 481 instrument was used throughout the experiment. IAA (isopropylaminoantipyrine) was shown to be the most suitable internal standard at absorption wavelength of 254 nm. A mixture of phosphate buffer (pH 5.5) and methanol (68:32) was used as the mobile phase with a flow rate of 2 ml.min-1, and YWG-C18H37 as stationary phase. Calibration curve was linear (gamma = 0.9998) in the concentration range of 0.1-5 micrograms.ml-1. The within day and day-to-day precision (RSD) of this method were 2.35% and 2.61%, respectively, with average recoveries of 99.3%-103.9%. No interference was found in the body fluid. The plasma samples of healthy volunteers were treated with acid and extracted with ether. The system of mobile phase and the process of blood sample treatment were simpler than those reported in literature. So, the method is suitable for the study of pharmacokinetics and clinical determination of blood level of analgin. The studies on bioavailabilities of analgin nasal drops were carried out in 8 men relative to intramuscular injection and 6 men relative to oral tablets, respectively, at the dose of 250 mg analgin in different preparations administered by cross-over method. The main pharmacokinetic parameters were shown in Table 3. The results indicate that analgin nasal drops exhibited a higher bioavailability (relative to injection) and faster absorption (relative to tablet). So, analgin is suitable to be developed as a nasal preparation.

[Toxicity of drugs on nasal mucocilia and the method of its evaluation].

Effect of solutions or suspensions of eight drugs including analgin, paracetamol, propafenone hydrochloride, propranolol hydrochloride, ephedrine hydrochloride, gentamycin sulfate, sodium deoxycholate and hydrocortisone on ciliary movement were evaluated with in vitro or in situ toad palate model and scanning electron microscope. In vitro toad palate model: 0.2 ml of test drug solution or suspension was applied to a piece of freshly dissected upper palate of toad. The mucocilia were examined with an optical microscope and the lasting time of ciliary movement was recorded after drug application. The upper palate was rinsed with physiological saline when the ciliary movement stopped. The lasting time of ciliary movement after rinsing was then recorded again. In situ palate model: 0.5 ml of test drug solution or suspension was applied to the upper palate of toad for 30 min, and rinsed with physiological saline. The palate was dissected out and the operation was carried out in a similar manner. The results showed that the in situ toad palate model is a satisfactory method for studying the ciliotoxicity of drugs. The in vitro toad palate model is unsuitable for suspension and gel. The results of the eight drugs revealed that ciliary movement is frequently affected by many drugs and, therefore, care must be taken in developing any nasal dosage form to ensure its least ciliotoxicity.

[Studies on octanol-water partition coefficient and nasal drug absorption].

In order to find out the quantitative relationship between physicochemical properties of drugs and their nasal absorption, diltiazem hydrochloride and paracetamol were selected as model drugs and their octanol-water partition coefficient was determined. In situ nasal recirculation method at different pH values was used to estimate the rate constant of nasal drug absorption in rats. Results showed that quantitative relationship existed between partition coefficient and nasal absorption constant, with correlation coefficient being 0.9761(n = 9). Besides methods of partition coefficient determination, the in situ nasal recirculation manipulation was also improved.

Highly tunable electrical properties in undoped ZnO grown by plasma enhanced thermal-atomic layer deposition.

Undoped ZnO thin films with highly tunable physical properties have been achieved by a new plasma enhanced thermal atomic layer deposition. This innovative yet straightforward approach has not been reported before but is demonstrated to be capable of controlling material properties in a wide range. The structural, electrical, and optical properties of the ZnO films were investigated by various characterization techniques. The growth mechanisms are discussed in terms of the chemistry of the additional O2 plasma on ZnO formation. Without extrinsic doping, the resistivity and carrier concentration of the ZnO films can be controlled up to seven and five orders of magnitude, respectively, by simply adjusting the plasma conditions. The electrical properties of the ZnO films were also found to correlate with significant changes in their optical properties. This extreme control and tunability of material properties is rarely achievable for undoped and even doped ZnO and should enhance the viability of ZnO in advanced device applications.