Search

3-Amino-4,4'-bi-1,2,4-triazole hydrochlorate and 3,3'-diamino-4,4'-bi-1,2,4-triazole ditosylate were obtained with the reduction of 3,3',5,5'-tetraazide-4,4'-bi-1,2,4-triazole (TABT) by (Ph)3P/H2O and the followed salt forming reaction with concentrated HCl and aqueous TsOH, respectively. Their structures were characterized with elemental analyses, IR, MS, 1H and 13C NMR spectra. The single crystals were cultivated and determined with X-ray diffraction, test results reveal that H+ combines with electron-rich N atom in triazole ring to form ionic salts, two N,N-linked triazoles are almost perpendicular to each other due to lower steric hindrance. The aromatic π…π stacking interactions and hydrogen bonds between molecules are observed. These two novel salts and their derivatives may be applied in coordination chemistry, medicinal chemistry and energetic materials.

In this paper, the spalling causes of backup rolls in a roughing mill of a hot strip rolling mill were investigated. The roughing mill withstood extreme service conditions with long service cycles for backup and work rolls, a large variety of the same width rolling campaigns, severe and non-uniform wear contours of backup and work rolls. Analysis of cyclic stress applied on backup rolls indicated that contact stress played a dominant role in rolling contact fatigue which led to spalling on the backup roll surface. A 3D finite element model of roll system was established and contact stresses between rolls in whole service periods of backup and work rolls were calculated. The simulation results showed that roll wear had significant impact on contact stress distribution. In particular, the severe and non-uniform U-typed wear contours of work rolls led to produce huge contact stress peak in two sides of the rolls, where existed large cracks by eddy current inspection of post-service backup rolls. Backup rolls stood thousands of times stress cycle in a service period, they were liable to fatigue damage in these areas. A new backup roll contour was developed to improve contact stress distribution and no spalling accidents were happened any longer after applied to the roughing mill.

A series of N-arylmorpholines 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l, 1m, 1n was obtained by cyclocondensation of arylamines and diethylene glycol dimesylate under microwave irradiation in an aqueous potassium carbonate medium. The reaction is rapid and convenient, and a variety of functional groups are tolerated in the process.

The addition of ZnO nanowhiskers (ZnOw) in lead zirconate titanate (PZT) matrices results in reinforced composite materials but deteriorates their electrical properties. In this study, novel piezoelectric PZT/ZnOw composites modified with Nb2O5 were successfully fabricated using solid-state sintering method. The experimental results showed that the addition of 0.5 wt% Nb2O5 resulted in highly dense and homogenous PZT composites after sintering at 1150°C, with good piezoelectric and ferroelectric properties similar to pure PZT, specifically piezoelectric constant d33=665 pC/N, electromechanical coupling factor kp=0.7, relative dielectric constant ɛ=5048, and remnant polarization Pr=30.2 μC/cm2. The “soft effect” of Nb5+ ions, reflected in the improvement of the aforementioned properties, is attributed to the accommodation of Nb5+ ions at the B sites of the lattice of PZT. Compared with the PZT/ZnOw reinforced composites, the mechanical properties were slightly improved by adding 0.5 wt% Nb2O5, where flexural strength σf of 128 MPa and fracture toughness KIC of 1.46 MPa·m1/2 were measured.

Hydroxyapatite coating on metal implants is an effective method to enhance bioactive properties of the metal surface. We report here a method to coat the Ti-6Al-4V alloy with hydroxyapatite crystals. After alkaline/heat treatment, the spontaneous growth of organoapatite on titanium alloy surface involves sequential preadsorption of titanium isopropoxide (TIPO) and the copolymer of acrylic acid and itaconic acid on the metal, followed by exposure to simulated body fluid (SBF). The organoapatite characterization of the coating was carried out by scanning electron microscopy, energy dispersive spectrometer, and X-ray diffraction. The copolymer of acrylic acid and itaconic acid overlayer which is rich of carboxylate groups can lead to the deposition of needle-like and homogeneous HA on the surface after immersion in SBF.

Background Nasopharyngeal carcinoma (NPC), particularly those tumors endemic to the Far East, commonly harbor Epstein-Barr virus (EBV), thought to serve as an important oncogenic promoter. Human papillomavirus (HPV) is associated with a proportion of upper aerodigestive tract carcinomas. We hypothesized that HPV might also contribute to the pathogenesis of NPC, and we queried whether geographic and racial distinctions may be identified between NPC of the Far East versus those diagnosed in Caucasian American patients with regard to the interrelationship of histologic subtype and viral infection. Materials and Methods Formalin-fixed paraffin-embedded tissue (FFPET) from 30 patients (6 Caucasian Americans, 1 Chinese American, 14 and 9 patients from Korea and China, respectively) were studied using the ligation-dependent polymerase chain reaction (LD-PCR). These cases were histologically classified according to the World Health Organization (WHO) schema for NPC. Consensus target probes complementary to the L1 region of over 30 HPV types, as well as target probes complementary to EBER-1 (EBV-related nontranslated latency-associated RNA), were used to amplify target sequences. Results Seven of 30 NPC (23%) contained HPV sequences. There were 6 Caucasian American patients with NPC; 3 cases (50%) were HPV positive (HPV+). Two of these Caucasian Americans had WHO type I tumors: one was HPV+ and EBV negative (EBV−) and the other was HPV−/EBV+. The remaining Caucasian American NPCs were WHO-II/III tumors which tested as follows: two were coinfected with HPV and EBV, the other two contained EBER but not HPV sequences. The single Oriental American patient had a WHO-III NPC which was HPV−/EBV+. Of the Eastern NPC patients, 4 (1 WHO-I, 3 WHO-II/III) of 23 (17%) NPCs contained HPV sequences as well as EBV. Conclusion Human papillomavirus appears to be uncommonly (17%) associated with NPC in patients from the Far East and was detected more often (50%) in NPC from American Caucasian patients. Some of these tumors conformed to our perceptions and expectations of NPC (eg, WHO-I tumors being EBV−/HPV+ and WHO-III tumors being EBV+/HPV−), but other tumors did not conform to these expectations (eg, WHO-III NPC occasionally harboring both HPV and EBV). There appears to be a broad profile in the relationship between HPV, EBV, and NPC histologic subtype. Unfortunately, the number of American Caucasian cases studied are too small to allow for strong conclusions. © 1999 John Wiley & Sons, Inc. Head Neck 21: 21–29, 1999.

This green way to N-arylmorpholines is performed without any phase-transfer or transition-metal catalyst.

An efficient and clean synthesis of N -arylpyrrolidines from arylamines and 1,4-dimesyloxybutane was developed using microwave irradiation in an aqueous potassium carbonate medium without any catalyst. The procedure is rapid, simple and convenient.

Monofunctionalized unsymmetrical diamines have been frequently used as starting materials in the synthesis of biological active agents and pharmacophores. 1 – 6 There have been some reports that ch...

Human papillomavirus (HPV) infection in cervix is the most important reason for cervical cancer, but only 2% cervical HPV infection will develop into cervical cancer. So how to identify patients at risk of progressive cervical lesions from those infected with HPV to avoid over treatment is a big issue in clinic. The aims of this study were to detect the expression of HPV L1 capsid protein and p16INK4a in cervical lesions and to investigate the combination expression of HPV L1 capsid protein and p16INK4a in cervical lesions and its diagnostic efficiency in clinic. Immunochemical method was used to detect the expression of HPV L1 capsid protein and p16INK4a in 169 cases of abnormal cytology. Histopathologic test was performed to identify cervical lesions of all the cases. χ2 test and spearman's rank correlation were used for statistical analysis. The diagnostic sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV), accuracy, and the area under the receive operating characteristic (ROC) curve (denoted by AZ) were calculated with SPSS 13.0. All the statistical tests were two sided at the 5% level of significance. L1 expression decreased (P < 0.001), but p16INK4a expression increased (P < 0.001) with histopathologic diagnosis increasing. The expression rates of HPV L1 capsid protein, p16INK4a, and L1(−)/p16(+) in cervical intraepithelial neoplasia (CIN)2, CIN3, and squamous-cell carcinoma were statistically different from those in CIN1 (P < 0.001). The expressions of HPV L1 capsid protein, L1(+)/p16(+), L1(+)/p16(−), and L1(−)/p16(−) were negatively correlated with the severity of cervical lesions (P < 0.001), whereas the expressions of p16INK4a and L1(−)/p16(+) were positively correlated with the severity of cervical lesions (P < 0.001). The specificity and AZ of combining L1 with p16 INK4a were statistically higher than L1 or p16 INK4a alone (P < 0.05). L1 and p16INK4a are useful biomarkers for the early diagnosis of cervical lesions. The combination of L1 and p16INK4a has a higher diagnostic accuracy than L1 or p16INK4a alone in diagnosis of cervical lesions. Diagn. Cytopathol. 2010;38:573–578. © 2009 Wiley-Liss, Inc.