Facile Synthesis of Hyperbranched Ethylene Oligomers and Ethylene/Methyl Acrylate Co-oligomers with Different Microscopic Chain Architectures.

Low-molecular-weight (MW) ethylene oligomers with hyperbranched microstructures are often difficult to be synthesized by traditional catalytic processes. In this study, a series of N-terphenyl iminopyridyl ligands and the corresponding Pd(II) and Ni(II) complexes bearing remote conjugated substituents with different electronic effects (H, Me, F, Cl, and tBu) were synthesized in a simple and efficient way. These Pd(II) and Ni(II) complexes were highly effective in the ethylene oligomerization and co-oligomerization with methyl acrylate (MA). Low-MW ethylene oligomers with hyperbranched microstructures were generated using the iminopyridyl Pd(II) and Ni(II) complexes in ethylene oligomerization. More importantly, polar functionalized ethylene-MA co-oligomers with low MWs and varying incorporation ratios were generated via ethylene and MA co-oligomerization using the Pd(II) complexes. Most notably, these ethylene oligomers obtained by different metal species showed a significant difference in microscopic chain architectures. The remote conjugated electron effect showed little effect on the polymerization parameters of the iminopyridyl system, which is very different from those of the salicylaldiminato system.

Direct Synthesis of Partially Chain-Straightened Propylene Oligomers and P-MA Co-Oligomers Using Axially Flexible Shielded Iminopyridyl Palladium Complexes.

In this study, a series of partially chain-straightened propylene oligomers and functional propylene−methyl acrylate (P-MA) co-oligomers were synthesized with 8-alkyl-iminopyridyl Pd(II) catalysts. The molecular weight and polar monomer incorporation ratio could be tuned by using Pd(II) catalysts with various 8-alkyl-naphthyl substituents (8-alkyl: H, Me, and n-Bu). In propylene oligomerization, all the 8-alkyl-iminopyridyl Pd(II) catalysts convert propylene to partially chain-straightened (119−136/1000 C) oligomers with low molecular weights (0.3−1.5 kg/mol). Among the catalysts, Pd1 with non-substituent (H) on the ligand showed the highest activity of 5.4 × 104 g/((mol of Pd) h), generating oligomers with the lowest molecular weight (Mn: 0.3 kg/mol). Moreover, polar-functionalized propylene-MA co-oligomers with very high incorporation ratios (22.8−36.5 mol %) could be obtained in the copolymerization using these 8-alkyl-iminopyridyl Pd(II) catalysts. Additionally, Pd1 exhibited the best performance in propylene-MA copolymerization as it displayed the highest MA incorporation ratio of up to 36.5 mol%. All the three catalysts are capable of generating partially chain-straightened P-MA co-oligomers and the activities decrease gradually while the molecular weight increases with the increasing steric hindrance of the alkyl substituent (H < Me < n-Bu). Compared to Pd4 with the rigid 8-aryl substituent, the flexible 8-alkyl-iminopyridyl Pd(II) catalysts (Pd1-3) not only showed much higher activities in the propylene oligomerization, but also yielded P-MA co-oligomers with significantly higher incorporation ratios in the propylene co-oligomerization.

Transvaginal three-dimensional ultrasound combined with HD flow model for uterus scar diverticulum.

To study the influencing factors of scar diverticulum formation and its monitoring methods, 141 people with a history of cesarean section and kidney deficiency and blood stasis were selected as subjects. The transvaginal ultrasound technique was used to divide the case into the scar diverticulum case group and the complete group, and the clinical situation was analyzed. Transvaginal three-dimensional ultrasound combined with HD flow pattern was used to analyze the morphology of uterus scar diverticulum and the parameters of peripheral muscle blood flow. The relationship between the size of scar diverticulum and its influencing factors, the location of the uterus and the number of cesarean sections were studied. Studies have found that retroposition of the uterus or the number of cross-cutting will increase the possibility of uterus scar diverticulum formation. Therefore, transvaginal three-dimensional ultrasound combined with HD flow mode can identify and diagnose scar diverticulum.

Thermus thermophilus DNA Ligase Connects Two Fragments Having Exceptionally Short Complementary Termini at High Temperatures.

Thermus thermophilus DNA ligase (Tth DNA ligase) is widely employed for cloning, enzymatic synthesis, and molecular diagnostics at high temperatures (e.g., 65 °C). It has been long believed that the complementary ends must be very long (e.g., >30 bp) to place two DNA fragments nearby for the ligation. In the current study, the length of the complementary portion was systematically varied, and the ligation efficiency was evaluated using the high resolution melting (HRM) method. Unexpectedly, very short oligonucleotides (7-10 nt) were successfully ligated on the complementary overhang attached to a dsDNA at 70 °C. Furthermore, sticky ends with the overhang of only 4 nt long, available after scission with many restriction enzymes, were also efficiently ligated at 45-70 °C. The ligation yield for the 6-nt-long sticky ends was as high as 80%. It was concluded that Tth DNA ligase can be used as a unique tool for DNA manipulation that cannot be otherwise easily accomplished.

Role of Ultrasound in the Detection of Rotator-Cuff Syndrome: An Observational Study.

BACKGROUND Physical tests are usually preferred to assess rotator-cuff syndrome but are insufficient to predict the morphology and size of the rotator-cuff. The objective of the study was to rate the ultrasound findings for patients with sudden shoulder pain and to determine potential predictors of the same. MATERIAL AND METHODS A total of 112 patients with sudden shoulder pain with rotator-cuff syndrome, suspected by orthopedic doctors, were subjected to ultrasonography. Real-time ultrasonography was done for the acromioclavicular joint, biceps, infraspinatus, posterior labrum, subscapularis, supraspinatus, teres minor tendon, and the sub-acromial-subdeltoid bursa. Each tendon was assessed via scanning planes in orientation as per longer and shorter axis, and from their myotendinous junction shoulder to bony insertions. Linear and logistic regression analysis were performed to predict the associations of medical history with rotator-cuff injury. RESULTS Ultrasonography identified that 82% of the enrolled patients had at least one particular cause of the rotator-cuff disorder. Among the rotator-cuff disorders, calcific tendonitis (54%) was observed more frequently followed by tendinopathy (32%), subacromial-subdeltoid bursitis (22%), and partial thickness tear (21%). Also, 46 patients (41%) had multiple findings. Older age (older than 40 years) was a strong predicting factor of rotator-cuff disorder (r²=0.36, P=0.0004). CONCLUSIONS Ultrasonography is a vital diagnostic procedure used by orthopedic surgeons for diagnosis of the rotator-cuff disorder(s) in patients with sudden shoulder pain.

Effects of secondary structures of DNA templates on the quantification of qPCR.

In the current design of quantitative polymerase chain reaction (qPCR) systems, the sequences of primers are the primary concerns. The secondary structures of DNA templates have not been much considered, although they should be also critically important. In this paper, various hairpins with different stem lengths and loop sizes are placed near primer-binding sites, and their effects on the amplification efficiency of qPCR are systematically investigated. When a hairpin is formed either in the inside of the amplicon or in its outside, the amplification is notably suppressed. The magnitudes of suppression increase with the increase in stem length and the decrease in loop size, and are especially significant for the hairpins formed inside the amplicon. With very long stems (e.g., 20-bp), the effect is still more drastic, and no targeted amplification products are formed. On the basis of melting temperature (Tm) measurements, these suppression effects of hairpins have been mostly ascribed to competitive inhibition of primer binding to the template. It has been concluded that, in order to design precise and reliable qPCR systems, at least 60-bp sequences around primer-binding sites, both inside and outside the amplicons, must be analyzed to confirm that stable secondary structures are not formed in the vicinity of primer-binding sites. Communicated by Ramaswamy H. Sarma.

The influence of NHCs on C-Si and C-C reductive elimination: a computational study of the selectivity of Ni-catalyzed C-H activation of arenes with vinylsilanes.

Density functional theory calculations were performed to investigate the mechanism and origins of the NHC-controlled selectivity of Ni-catalyzed C-H activation of arenes with vinylsilanes. The key to the selectivity is the different impacts of NHCs on the C-Si/C-C reductive elimination of the square-planar/T-shaped intermediate.

Efficacy of patients' preferred exercise modalities in chronic obstructive pulmonary disease: A parallel-group, randomized, clinical trial.

INTRODUCTION: Physical exercise effectively improves health-related quality of life in patients with chronic obstructive pulmonary disease (COPD). However, application of this medical intervention is problematic, due to poor adherence to the exercise program or unawareness of the significance of this intervention. OBJECTIVE: To determine whether COPD patients who adopted personal-preferred exercise modalities (PPEMs) for daily training would demonstrate sustained benefits due to improved adherence. METHODS: Stable COPD patients were randomly assigned to the daily PPEMs group or the control group (without extra exercise apart from daily life activities). All other treatments were similar. The primary outcome was the health-related quality of life (HRQoL), measured with St. George's Respiratory Questionnaire (SGRQ) score at 12 months. Other measures included the Borg dyspnea score, 6-min walking distance (6MWD) and lung function variables. RESULTS: The intention-to-treat (ITT) population included 94 patients, 68 of them completed the study protocol over 12 months (the PP-population). A greater decline of SGRQ score (improvement of HRQoL) in the PPEMs group than that in the controls was demonstrated over 12 months (-19.1 vs -9.0 in the ITT population and -19.1 vs -8.7 in the PP population, P ≤ .001 for all comparisons), the reduction exceeded the minimal clinically important difference of ≥ 4 points. The PPEMs group also showed a greater reduction than the control group in Borg score at 12 months in the ITT and the PP population as well (P < .01). No significant improvement was found in 6MWD or in lung function variables. CONCLUSIONS: COPD patients could benefit from extra daily PPEMs, and the gain may sustain at least for 1 year.

Ultrasound reverses chemoresistance in breast cancer stem cell like cells by altering ABCG2 expression.

Doxorubicin (DOX) resistance in breast cancer largely results from the breast cancer stem cell like cells (BCSCs) which could be targetted to improve the efficacy of chemotherapy. Cell permeabilization using microbubbles (MBs) and ultrasound (US) have the potential for delivering molecules into the cytoplasm. We aim to evaluate a new methodology of US on BCSCs. First, our findings indicated that ALDHA1+ spheres which were derived from fresh primary breast cancer samples displayed stem cell like features and were resistant to DOX. In patient cohort, we revealed the presence of a variable fraction of ALDHA1+cells in nine out of ten. We, for the first time, showed a new US-MB treatment condition which could be used on ALDHA1+ BCSCs by fluorescence measurement and calcein assay. Next, we demonstrated the efficacy of combined treatment on human BCSCs in vitro and in vivo using DOX and US-MB: the combined treatment with much reduced drug dosage significantly suppressed the stem cell like features of BCSCs and induced BCSCs apoptosis. Furthermore, we suggested that decreased ABCG2 level might be one of the mechanisms by which US-MB medicated DOX treatment. In conclusion, this new US-MB treatment condition has clinical potential in breast cancer therapy by targetting BCSCs; thereby holding benefits for breast cancer patients.

[Clinical application of tibial composite saphenous nervetissue flap for the treatment of traumatic bone-skin defect of leg].

OBJECTIVE: To investigate the effect of tibial composite saphenous nerve tissue flap in repairing traumatic bone-skin defect of leg. METHODS: From February 2009 to May 2015, 23 patients with focile skin defect caused by trauma were treated, including 18 males and 5 females, aged from 8 to 59 years old with an average age of 35.6 years old. Length of tibia bone cortex defect ranged from 4 to 12 cm, width ranged from 2 to 2.5cm, skin defect ranged from 8 cm× 3 cm to 18 cm× 11 cm, all the wound surfaces had purulent exudation. Cross shift and ipsilateral shift methods of tibial composite saphenous nerve tissue flap were used to reconstruct continuity of the injured limb tibial brace and repair wound surface. Cutting flap ranged from 9 cm× 4 cm to 20 cm × 12 cm, bone flap length was 6 to 15 cm, width was 1.5 to 2.5 cm. Fracture healing time and recovery of limb function were observed. RESULTS: At 3 to 5 months after operation, bone flap and area of affected area were healed with an average of 4.7 months. Twenty-three cases were followed up for 6 months to 5 years with an average of 30.3 months. Thirteen patients were able to walk without abnormal gait and could be engaged into original work. According to Enneking evaluation systems, 13 patients obtained excellent results, 8 moderate and 2 poor. CONCLUSIONS: With tibial composite saphenous nerve tissue flap transplantation at stage one to repair tibia and skin defects according to specific condition of affected limbs has a high rate of success and creates less damage to region of limb injury, which is an ideal method to repair skin defect of focile.

The effects of eye drops on corneal thickness in adult myopia.

PURPOSE: To study the effects of Complex Tropicamide (0.5% Tropicamide and 0.5% phenylephrine HCI) and Saline solution on corneal thickness in adult myopic patients with the Orbscan II system. SETTING: Department of Ophthalmology, Yantai Yuhuangding Hospital. DESIGN: Prospective, nonrandomized, clinical trial. METHODS: The thinnest pachymetry of the cornea was obtained before and 1.5 hours after administration of three drops of Complex Tropicamide to the left eyes of 58 patients (58 eyes) and Saline solution to their 31 right eyes, respectively. The corneal thickness of the other 27 right eyes before and 1.5 hours after eyelid closure without exposure to eye drops was used as the control group. RESULTS: The thinnest pachymetry of the cornea was significantly higher after exposure to eye drops in the Tropicamide group (23.36 +/- 15.01 microm; t = -11.855, P < 0.001). Similar findings were also noted in the Saline group (7.13 +/- 8.11 microm, t = -4.894, P < 0.001). The difference between the two groups was also significant (t = 6.737, P < 0.001). There were no statistically changes in corneal thickness in control group. The drops tested have no effect on the location of the thinnest corneal site and its distance form the visual axis. CONCLUSION: Eye drops including Saline solutions may have significant effects on the corneal thickness in myopia, and this may have implications for corneal refractive surgery.