The coadsorption behavior of two complementary DNA bases,adenine(A) and thymine(T),was studied on Au(111) electrode by cyclic voltammetry(CV) and electrochemical scanning tunneling microscopy ( ECSTM) in aqueous solution. From the CVs,the coadsorption behavior of A and T was more closed to the adsorption behavior of A. In the potential range of physisorption,high- resolution ECSTM images of revealed that a new super-structure was formed by the hydrogen bonds between A and T. A molecular model of the super-structure was proposed based on the STM results and the possible hydrogen bonds between A and T.

Objective To study the induction of nitrous oxide(N2 O)and to compare safety and effec-tiveness of conscious sedation by nitrous oxide inhalation and intravenous sedation with propofol for upper gas-trointestinal(UGI)endoscopy.Methods A total of 400 patients undergoing UGI endoscopy in our hospital from April 2013 to October 2013 were randomly assigned to two groups,N2 O inhalation group(n=200)and in-travenous propofol group(n=200).The systolic pressures,diastolic pressures,heart rates and oxygen satura-tion,onset time,procedure duration,degree of sedation,recovery time,length of hospital stay,complica-tions,satisfaction ratings of doctors and patients,and the number of patients willing to accept the examination again were analyzed.Results The mean time of ideal anesthesia state for N2 O was (3. 16 ±0. 65 )min and there was no difference between the male and female(3. 16 ±0. 71)min vs.(3. 16 ±0. 58)min,t=0. 006,P>0. 05).The mean concentration was (43. 68 ±5. 05 )%,which was higher in male than that in female [(45. 3 ±4. 99)% vs.(41. 46 ±4. 30)%,t=3. 042,P<0. 05].Compared with before,the systolic pres-
sures,diastolic pressures,heart rates and oxygen saturation of patients in the propofol group significantly re-duced during the procedure(P<0. 05),while the same measurements excluding oxygen saturation for those in the N2 O group significantly increased(P<0. 05 ).Compared with the propofol group,patients inhaling N2 O had significantly shorter recovery and hospital stay time,but a longer onset time and procedure duration(P<0. 05 ).Complications that occurred in some patients of propofol group included hyoxemia,hypotension,brady-cardia,while the major complication in the N2 O group was nausea.The satisfaction ratings of doctors or pa-tients and the number of patients willing to accept the examination again in N2 O group were smaller than those in propofol group(86 ±3. 7 vs.96 ±2. 6,87 ±2. 8 vs.98 ±1. 2,87%vs.99%,P<0. 05).Conclusion Both conscious sedation by N2 O inhalation and intravenous sedation with propofol are effective for diagnostic UGI en-doscopy,but the safety of the former is superior to the latter.The key to complete the conscious sedation by ni-trous oxide inhalation is to accurately identify the ideal anesthesia state of N2 O.It is significant to pay attention to the nine factors concerning safe and effective sedation during operation.

Objective To detect the mitochondrial microsatellite instability (mtMSI) and Helicobacter pylori (Hp) infection status in esophageal squamous cell carcinoma (ESCC),and to analyze their clinical significance in the diagnosis of ESCC.Methods The mtMSI and Hp infection status were examined by immunohistochemical SP method in 93 cases of ESCC and their normal control tissues.The relationship between Hp and mtMSI and their correlations with the clinicopathological features of ESCC were analyzed.Results The Hp positive rates of ESCC group and control group were 61.3％ (57/93) and 20.4％ (19/93) respectively,and there was statistically significant difference between the two groups (x2 =32.127,P ＜0.001).The mtMSI positive rates of ESCC group and control group were 34.4％ (32/93) and 0 (0/93) respectively,and there was statistically significant difference between the two groups (x2 =38.649,P ＜0.001).The Hp infection was correlated with tumor infiltrating degree (x2 =22.213,P ＜ 0.001) and lymph node metastasis (x2 =8.318,P =0.004),but was not correlated with gender (x2 =0.330,P =0.565),major axis of tumor (x2 =0.692,P =0.406),gross type (x2 =1.006,P =0.316),differentiated degree (x2 =0.665,P =0.415).The mtMSI was not correlated with gender (x2 =0.163,P =0.686),major axis of tumor (x2 =0.384,P =0.530),gross type (x2 =0.422,P =0.516),differentiated degree (x2 =0.213,P =0.645),infiltrating degree (x2 =0.001,P =0.979) or lymph node metastasis (x2 =0.039,P =0.843).The Hp infection was positively associated with mtMSI in ESCC (r =0.864,P =0.006).Conclusion The positive rates of Hp and mtMSI in ESCC are higher than those in normal tissues,and there is a close relationship between Hp and mtMSI.Hp is also associated with the progression of ESCC.

Neurotrophic keratopathy (NK) is a degenerative disease in which damage to the corneal nerves leads to corneal hypoesthesia and even blindness.Traditional NK treatments aim at supporting corneal healing and preventing progression of corneal damage.In recent years, corneal neurotization has made some progress in NK.Compared with traditional treatment, it can not only solve the problem of corneal nerve defect, and avoid the subsequent keratopathy, but also significantly restore corneal sensitivity, corneal epithelium and vision.Corneal neurotization surgery methods are mainly divided into direct corneal neurotization (DCN) and inderect corneal neurotization (ICN).At present, this surgical method has gradually been used clinically, and has achieved satisfactory effects on unilateral NK caused by herpes virus and neuroma, as well as bilateral NK.However, it is little known about the surgical treatment of NK caused by dry eye, diabetes, and chronic glaucoma.In the future, multi-center prospective randomized studies can be conducted to further improve the treatment of NK with other causes.This article introduces this new surgical technique from three aspects, the specific surgical procedures of corneal neurotization, the selection of surgical methods, and the timing of the operation.

Due to their prolonged exposure to the external environment, eyes are susceptible to various infectious diseases of the ocular surface.In recent years, the resistance of pathogens to antimicrobial agents has led to poor treatment outcomes and significant deterioration in patients' vision and quality of life.Nowadays, ocular surface infectious diseases have become a global public health concern, necessitating the search for a safe and effective treatment.Antimicrobial peptides (AMPs), which act as antibiotic analogues, exhibit broad-spectrum antibacterial activity and are effective against a range of microbial infections, including bacteria, viruses, fungi, and parasites.AMPs play a crucial role in combating ocular surface infections.This review discusses the structure and function of AMPs, the mechanism of action of AMPs in ocular surface infections, the role of endogenous AMPs in fighting various ocular surface pathogens, the impact of exogenously induced AMPs on ocular surface infections, and recent research advances in AMPs.

Objective To evaluate the effects of nitrous oxide inhalation on conscious sedation of patients during colonoscopy and analyze its risk factors. Methods From October 2016 to July 2017, a total of 154 patients undergoing colonoscopy were included in the study. The comfort level was rated using Modified Gloucester Comfort Scale ( MGCS). Factors affecting comfort level were analyzed by univariate analysis and multivariate Logistic regression, and then a comfort stratification predicting model was created. Results All 154 patients finished colonoscopy. The mean time of ideal anesthesia state was 195. 15 s. Among the 154 cases, 115 ( 74. 7%) were identified as comfort ( grade of MGCS from 1 to 3) and 39 (25. 3%) were rated as discomfort ( grade of MGCS from 4 to 5). Multivariate regression indicated that age ≥60 years ( P＝0. 000, OR＝1. 074, 95%CI: 1. 036-1. 114) and mild anxiety ( P＝0. 018, OR＝3. 338, 95%CI: 1. 227-9. 079) were associated with comfort level during colonoscopy.The established model with the age (X1) and mild anxiety (X2) was P＝eY/(1+eY), Y＝－3. 812+0. 071X1+1. 205X2(no anxiety was assigned 1, mild anxiety was assigned 2), and the area under the receiver operating characteristics curve was 0. 746 (95%CI: 0. 661-0. 830), which showed moderate predictive power of the final model. The model reached the highest predictive accuracy when the Yoden Index was 0. 838 with sensitivity of 50. 4% and specificity of 89. 7% for predicting comfort level of patients in conscious sedation status induced by nitrous oxide inhalation during colonoscopy. Conclusion Nitrous oxide can ease pain during colonoscopy, especially for patients over 60 years old and with anxiety. We can use it as an option according to actual circumstance in practice.

The effects of berberine on the expression of hepatocyte nuclear factor-4α (HNF-4α) in liver of rats with fructose-induced insulin resistance and the molecular mechanism of berberine preventing insulin resistance were investigated. The experimental animals were divided into two groups of 16 animals each. The control group received a control routine diet containing 60% carbohydrate, and the study group a high-fructose diet containing 60% fructose as the sole source of carbohydrate. At the end of 6 weeks these were each subdivided into two groups. One was administered with berberine [187.5mg/(kg·d) in 5g/L carboxymethyl cellulosel] by intragastric intubation and the other group was treated with a vehicle (5g/L carboxymethyl cellulose). The rats were fed on the same dietary regimen for the next 4 weeks. After the experimental period of 10 weeks, plasma glucose, insulin and triglyceride levels were measured. HOMA insulin resistance index (HOMA-IR) was assayed. Immunohistochemistry, semiquantitative RT-PCR and western blot were used to detect the expression of HNF-4α in liver. Compared with control diet, fructose feeding induced hyperinsulinemia, HOMA-IR and increased triglyceride (all P<0.01). Berberine prevented the rise in plasma insulin (P<0.01), HOMA-IR (P<0.01) and triglyceride (P<0.05) in the fructose-fed rats. No change in plasma glucose was seen among these groups. The mRNA and protein expression of HNF-4α was decreased in the fructose-fed rats, but berberine could promote its expression. It was concluded that berberine could prevent fructose-induced insulin resistance in rats possibly by promoting the expression HNF-4α in liver.