Study on the mechanism of multidimensional cutting teeth and the influencing factors of rock breaking efficiency

The innovative cutting mechanism of multi-dimensional teeth presents a groundbreaking approach to drill bit design, particularly optimizing drilling efficiency in challenging geological formations such as interlayers and gravel-rich layers within the Changqing Oilfield. Nevertheless, compared to conventional flat-tooth PDC drill bits, several aspects of the cutting mechanism and design parameters for multi-dimensional teeth require further elucidation. This article employs a linear cutting finite element model to establish cutting models for traditional flat teeth and two distinct types of multi-dimensional teeth, designated as Ridge and Benz. It systematically investigates the influence of varying cutting parameters on the effectiveness of rock-crushing within the multi-dimensional tooth-cutting mechanism. This study conducts laboratory-based single-tooth rock-crushing experiments to validate the numerical simulation results. Furthermore, applying principles derived from soil plastic mechanics contrasts the stress states experienced by rocks during the rock-crushing process between multi-dimensional teeth and conventional flat teeth, shedding light on the rock-crushing mechanism employed by multi-dimensional teeth. This research categorizes PDC cutting teeth on the drill bit into two groups: those near the center and those near the outer shoulder. A linear cutting model for teeth positioned near the outer shoulder is developed to analyze the impacts of different rake angles, side clearance angles, and welding errors on the tooth helix angle and the rock-crushing efficiency of the Benz tooth. This comprehensive study is a valuable reference for tailored drill bit design and holds potential for publication in a prestigious scientific journal.

[Investigation of treatment and analysis of prognostic risk on enterocutaneous fistula in China: a multicenter prospective study]

Objective: To investigate the diagnosis and treatment for enterocutaneous fistula (ECF) in China, and to explore the prognostic factors of ECF. Methods: A multi-center cross-sectional study was conducted based on the Registration System of Chinese Gastrointestinal Fistula and Intra-Abdominal Infections to collect the clinical data of ECF patients from 54 medical centers in 22 provinces/municipalities from January 1, 2018 to December 31, 2018. The clinical data included patient gender, age, length of hospital stay, intensive care unit (ICU) admission, underlying diseases, primary diseases, direct causes of ECF, location and type of ECF, complications, treatment and outcomes. All medical records were carefully filled in by the attending physicians, and then re-examined by more than two specialists. The diagnosis of ECF was based on the clinical manifestations, laboratory/imaging findings and intraoperative exploration. Results: A total of 1521 patients with ECF were enrolled, including 1099 males and 422 females, with a median age of 55 years. The top three primary diseases of ECF were malignant tumors in 626 cases (41.2%, including 540 gastrointestinal tumors, accounting for 86.3% of malignant tumors), gastrointestinal ulcers and perforations in 202 cases (13.3%), and trauma in 157 cases (10.3%). The direct causes of ECF were mainly surgical operation in 1194 cases (78.5%), followed by trauma in 156 (10.3%), spontaneous fistula due to Crohn's disease in 92 (6.0%), radiation intestinal injury in 41 (2.7%), severe pancreatitis in 20 (1.3%), endoscopic treatment in 13 (0.9%) and 5 cases (0.3%) of unknown reasons. All the patients were divided into three groups: 1350 cases (88.7%) with simple ECF, 150 (9.9%) with multiple ECF, and 21 (1.4%) with combined internal fistula. Among the patients with simple ECF, 438 cases (28.8%) were jejuno-ileal fistula, 313 (20.6%) colon fistula, 170 (11.2%) rectal fistula, 111 (7.3%) duodenal fistula, 76 (5.0%) ileocecal fistula, 65 (4.3%) ileocolic anastomotic fistula, 55 (3.6%) duodenal stump fistula, 36 (2.4%) gastrointestinal anastomotic fistula, 36 (2.4%) esophagogastric/esophagojejunal anastomotic fistula, 29 (1.9%) gastric fistula and 21 (1.4%) cholangiopancreatiointestinal. Among all the simple ECF patients, 991 were tubular fistula and 359 were labial fistula. A total of 1146 patients finished the treatment, of whom 1061 (92.6%) were healed (586 by surgery and 475 self-healing) and 85 (7.4%) died. A total of 1043 patients (91.0%) received nutritional support therapy, and 77 (6.7%) received fistuloclysis. Infectious source control procedures were applied to 1042 patients, including 711 (62.0%) with active lavage and drainage and 331 (28.9%) with passive drainage. Among them, 841 patients (73.4%) underwent minimally invasive procedures of infectious source control (replacement of drainage tube through sinus tract, puncture drainage, etc.), 201 (17.5%) underwent laparotomy drainage, while 104 (9.1%) did not undergo any drainage measures. A total of 610 patients (53.2%) received definitive operation, 24 patients died within postoperative 30-day with mortality of 3.9% (24/610), 69 (11.3%) developed surgical site infection (SSI), and 24 (3.9%) had a relapse of fistula. The highest cure rate was achieved in ileocecal fistula (100%), followed by rectal fistula (96.2%, 128/133) and duodenal stump fistula (95.7%,44/46). The highest mortality was found in combined internal fistula (3/12) and no death in ileocecal fistula. Univariate prognostic analysis showed that primary diseases as Crohn's disease (χ(2)=6.570, P=0.010) and appendicitis/appendiceal abscess (P=0.012), intestinal fistula combining with internal fistula (χ(2)=5.460, P=0.019), multiple ECF (χ(2)=7.135, P=0.008), esophagogastric / esophagojejunal anastomotic fistula (χ(2)=9.501, P=0.002), ECF at ileocecal junction (P=0.012), non-drainage/passive drainage before the diagnosis of intestinal fistula (χ(2)=9.688, P=0.008), non-drainage/passive drainage after the diagnosis of intestinal fistula (χ(2)=9.711, P=0.008), complicating with multiple organ dysfunction syndrome (MODS) (χ(2)=179.699, P<0.001), sepsis (χ(2)=211.851, P<0.001), hemorrhage (χ(2)=85.300, P<0.001), pulmonary infection (χ(2)=60.096, P<0.001), catheter-associated infection (χ(2)=10.617, P=0.001) and malnutrition (χ(2)=21.199, P<0.001) were associated with mortality. Multivariate prognostic analysis cofirmed that sepsis (OR=7.103, 95%CI:3.694-13.657, P<0.001), complicating with MODS (OR=5.018, 95%CI:2.170-11.604, P<0.001), and hemorrhage (OR=4.703, 95%CI: 2.300-9.618, P<0.001) were independent risk factors of the death for ECF patients. Meanwhile, active lavage and drainage after the definite ECF diagnosis was the protective factor (OR=0.223, 95%CI: 0.067-0.745, P=0.015). Conclusions: The overall mortality of ECF is still high. Surgical operation is the most common cause of ECF. Complications e.g. sepsis, MODS, hemorrhage, and catheter-associated infection, are the main causes of death. Active lavage and drainage is important to improve the prognosis of ECF.

[Comparative study on image quality of third-generation dual-source CT pulmonary angiography combined with advanced modeled iterative reconstruction]

Objective: To quantitatively evaluate the quality of advanced modeled iterative reconstruction (ADMIRE) combined with 70 kVp and linear blending images in low dose dual energy (70 kVp/sn150 kVp) pulmonary angiography. Methods: A total of 74 cases with normal BMI underwent dual-source CT dual-energy pulmonary angiography with small amount of contrast medium (30 ml) from 2015 to 2017 from the First Affiliated Hospital of Zhengzhou University were randomly assigned to protocol Ⅰ(100 kVp/sn140 kVp) or protocol Ⅱ(70 kVp/sn150 kVp). 70 kVp+ ADMIRE (group 1), linear blending+ ADMIRE (group 2), 100 kVp+ SAFIRE (group 3) images were obtained. CT value and noise standard deviation (SD) of pulmonary arteries were measured in pulmonary trunk artery, left pulmonary artery and left superior pulmonary artery, then SNR and CNR were calculated. Radiation dose parameters (CTDIvol, DLP) were recorded. Results: CT values of pulmonary artery of group 1 were significantly higher than those in group 2 and 3 (both P<0.05). In group 2, SD value of pulmonary artery was lower than that of group 1 and 3(both P<0.05). SD value of pulmonary trunk and left pulmonary artery in group 1 was higher than that in group 3 (P<0.05), SD value of left superior pulmonary artery had no significant difference between group 1 and group 3 (P>0.05). SNR and CNR value in group 1 and group 2 had no statistical difference, but they were both higher than that in group 3 (both P<0.05). The effective dose of protocolⅠwas 46% lower than protocol Ⅱ. Conclusion: ADMIRE combined with 70 kVp and linear blending images are better than SAFIRE combined with 100 kVp images, and radiation dose is reduced.70 kVp/sn150 kVp with small amount of contrast medium (30 ml) is a feasible dual energy pulmonary artery scanning protocol.

Downregulation of SWI5 and CTC1 genes: hepatitis B virus DNA polymerase transactivated protein 1-mediated inhibition of DNA repair

Hepatitis B virus (HBV) DNA polymerase transactivated protein 1 (HBVDNAPTP1) is a novel protein upregulated by HBV DNA polymerase, which has been screened by suppression subtractive hybridization technique (SSH) (GenBank Acc. No. AY450389). A vector pcDNA3.1 (-)/myc-His A-HBVDNAPTP1 was constructed and used to transfect acute monocytic leukemia cell line THP-1. HBVDNAPTP1 expression was detected by Western blot analysis in the cells. A cDNA library of genes downregulated by HBVDNAPTP1 in THP-1 cells was made in pGEM-T Easy using SSH. The cDNAs were sequenced and analyzed with BLAST search against the sequences in GenBank. Some sequences, such as DNA repair protein SWI5 homolog (SWI5) and CTS telomere maintenance complex component 1 (CTC1), might be involved in DNA repair. Protein expression of SWI5 and CTC1 was identified by Western blot in THP-1 cells. HBVDNAPTP1 could downregulate the expression of SWI5 and CTC1 at translation level.

miRNAs are required for the terminal differentiation of white matter astrocytes in the developing CNS

While the regulation of the neurogenesis and oligodendrogenesis by microRNAs has been intensively studied, little is known about the role of microRNAs (miRNAs) in the development of astrocytes. Here, we report that microRNAs play an essential role in the differentiation and maturation of white matter astrocytes in mouse spinal cord tissues. In glial fibrillary acidic protein (GFAP)/Dicer conditional mutants, the initial generation of astrocyte progenitor cells was normal in the spinal cord. However, there was a much reduced number of GFAP+ astrocytes with shorter processes in the white matter of mutant tissues. In contrast, the expression of gray matter protoplasmic astrocyte marker was not affected. Together, our studies indicated that miRNAs are required for the differentiation and morphological maturation of white matter fibrous astrocytes in the developing spinal cord.

Expression of HMGA2 in bladder cancer and its association with epithelial-to-mesenchymal transition

OBJECTIVES

High mobility group protein2 (HMGA2) and epithelial-to-mesenchymal transition are both related to progress of bladder cancer, however, the relationship between HMGA2, E-cadherin and vimentin in bladder cancer is not yet known. Thus, this study has examined expression of HMGA2, E-cadherin and vimentin in bladder cancer and investigated their relationship.

MATERIALS AND METHODS

The 5637 bladder cancer cell line and SV-HUC-1 normal uroepithelial cells were used to study expression of HMGA2, E-cadherin and vimentin using RT-PCR and western blotting. Paraffin wax-embedded bladder cancer tissues were used to study protein expression using immunohistochemistry and χ(2) analysis and Kendall's correlation were utilized statistical methods.

RESULTS

Overexpression of HMGA2 was associated with down-regulation of E-cadherin and up-regulation of vimentin in the 5637 bladder cancer line. A total of 49 paraffin wax-embedded tissues of transitional cell bladder cancer were used. Positive expression levels of HMGA2 protein and vimentin were 41 and 43% in bladder tissues, respectively. No expression of E-cadherin was found in 43%. Expression of HMGA2, loss of E-cadherin and expression of vimentin are all significantly correlated with bladder cancer grade and stage. Loss of E-cadherin and expression of vimentin both correlated with recurrence of the bladder cancer.

CONCLUSIONS

Expression of HMGA2 was closely associated with occurrence of epithelial-to-mesenchymal transition. Expression of HMGA2, loss of E-cadherin and expression of vimentin may indicate high degree malignancy of bladder cancer. Loss of E-cadherin expression and positive expression of vimentin may predict recurrence of bladder cancer.

Single-Molecule Conductance of Redox Molecules in Electrochemical Scanning Tunneling Microscopy

Experimental data and theoretical notions are presented for 6-[1'-(6-mercapto-hexyl)-[4,4']bipyridinium]-hexane-1-thiol iodide (6V6) "wired" between a gold electrode surface and tip in an in situ scanning tunneling microscopy configuration. The viologen group can be used to "gate" charge transport across the molecular bridge through control of the electrochemical potential and consequently the redox state of the viologen moiety. This gating is theoretically considered within the framework of superexchange and coherent two-step notions for charge transport. It is shown here that the absence of a maximum in the Itunneling versus electrode potential relationship can be fitted by a "soft" gating concept. This arises from large configurational fluctuations of the molecular bridge linked to the gold contacts by flexible chains. This view is incorporated in a formalism that is well-suited for data analysis and reproduces in all important respects the 6V6 data for physically sound values of the appropriate parameters. This study demonstrates that fluctuations of isolated configurationally "soft" molecules can dominate charge transport patterns and that theoretical frameworks for compact monolayers may not be directly applied under such circumstances.

Deuterium isotope effect on the intramolecular electron transfer in Pseudomonas aeruginosa azurin

Intramolecular electron transfer in azurin in water and deuterium oxide has been studied over a broad temperature range. The kinetic deuterium isotope effect, k(H)/k(D), is smaller than unity (0.7 at 298 K), primarily caused by the different activation entropies in water (-56.5 J K(-1) mol(-1)) and in deuterium oxide (-35.7 J K(-1) mol(-1)). This difference suggests a role for distinct protein solvation in the two media, which is supported by the results of voltammetric measurements: the reduction potential (E(0')) of Cu(2+/+) at 298 K is 10 mV more positive in D(2)O than in H(2)O. The temperature dependence of E(0') is also different, yielding entropy changes of -57 J K(-1) mol(-1) in water and -84 J K(-1) mol(-1) in deuterium oxide. The driving force difference of 10 mV is in keeping with the kinetic isotope effect, but the contribution to DeltaS from the temperature dependence of E(0') is positive rather than negative. Isotope effects are, however, also inherent in the nuclear reorganization Gibbs free energy and in the tunneling factor for the electron transfer process. A slightly larger thermal protein expansion in H(2)O than in D(2)O (0.001 nm K(-1)) is sufficient both to account for the activation entropy difference and to compensate for the different temperature dependencies of E(0'). Thus, differences in driving force and thermal expansion appear as the most straightforward rationale for the observed isotope effect.

[Evaluation of the effect of aging on the retinal nerve fiber layer thickness using scanning laser polarimeter]

OBJECTIVE

To study age-related effects on the retinal nerve fiber layer thickness (RNFLT).

METHODS

75 eyes of 75 normal volunteers were recruited. Their ages ranged from 20 to 66 years. They were divided into five age groups of 15 subjects each. We measured each subject's RNFLT using scanning laser polarimeter. The mean RNFLT within the 1.5 disc diameter ring around the optic nerve papilla and its four quadrants (superior, temporal, inferior and nasal) was calculated.

RESULTS

The mean +/- SD of RNFLT was 76.4 +/- 7.50 microm, 71.5 +/- 7.3 microm, 72.1 +/- 3.9 microm, 66.7 +/- 7.2 microm and 67.4 +/- 8.5 microm, respectively.

CONCLUSIONS

The RNFLT decreases with aging in the normal healthy eye.

["Neural capacity" index correlates with neuroretinal rim area of glaucomatous eyes better than light sensitivity]

We compared the relationship between the neuroretinal rim area and the neural capacity (NC) index of high-pass resolution perimetry (HRP) and the differential light sensitivity (DLS) of a Humphrey Field Analyzer (HFA). Subjects were 40 eyes of 27 normal-tension glaucoma (NTG) patients. The total rim area and the area of its temporal, superior, nasal, and inferior quadrants were determined with a confocal laser tomographic scanner. Mean local NC (MLNC) was calculated using the resolution thresholds corresponding to the quadrant. Mean local DLS (MLDLS) was calculated using the data of program 30-2 of HFA. In a total of 40 eyes, NC and mean deviation were significantly correlated with the total rim area (rs = 0.422, p < 0.01: rs = 0.360, p < 0.05, respectively). NC was also significantly correlated with the total rim area in 19 eyes with early visual field changes, but not in 21 eyes with advanced changes. MLNC was significantly correlated with the superior and inferior rim areas, and MLDLS was significantly correlated with the inferior rim area. These results indicate that indices of HRP may relate to glaucomatous optic disc changes better than those of HFA in NTG, especially in patients with early visual field defects.

[Interaction between a prostaglandin F2 alpha derivative, UF-021, and pilocarpine in ocular hypotensive therapy]

We investigated the ocular hypotensive effect of concomitant use of pilocarpine and UF-021, a prostaglandin-related compound, in 10 cases (20 eyes) of primary open-angle glaucoma or ocular hypertension. Following a 2- to 4-week-washout of all anti-glaucoma medication, 0.12% UF-021 was instilled twice daily into both eyes of 5 patients and 1% pilocarpine four times daily in 10 eyes of the remaining 5 patients for 2 weeks. Then both eye-drops were used concomitantly for the subsequent 2 weeks. Intraocular pressure (IOP) measurement and slit-lamp examination were carried out from one hour prior to the instillation to 4 hours after the instillation at the end of the washout period, the single-use period, and the concomitant-use period. Although no significant difference was found between IOPs of the single-use and concomitant use periods at each measurement time point, a significant difference was found between them when all the measured IOP values were pooled. No changes in episcleral venous pressure nor adverse effects were noted. We concluded that the concomitant use of pilocarpine and UF-021 causes an additive ocular hypotensive effect in clinical settings.

[Thin layer chromatography and extractive technology of Panax japonicum C.A. Mey. var. major (Burk.) C. Y. Wu et K. M. Feng growing in Qingba Mountain Area]

Chemical components of the root, stem and leaves of Panax japonicum var. major were compared with those of Radix ginseng and Radix notoginseng by TLC. The results showed that the total saponin of the root Panax japonicum var. major was closer to that of Radix ginseng and the total saponin of its stem and leaves was similar to Radix notoginseng. A better extractive technology was obtained after isolating and purifying the whole herb of Panax japonicum var. major by ethyl alcohol at different concentrations. The components were compared by TLC. The results showed that with 60% ethyl alcohol the yield of the total extract was 17.15%.

[Ultrafiltration properties in preparing injections of Chinese medicinal herbs using a J-48 ultrafilter]

Four injections of single Chinese medicinal herbs and 3 medical solutions of pure substances showing impurities were prepared by J-48 ultrafilter. The retention rate of effective compounds and the clearance rate of impurity of each injection and solution before and after ultrafiltration were examined by a UV 265-FW Ultraviolet-spectrophotometer (Shimadzu, Japan).