Improving the Drilling Parameter Optimization Method Based on the Fireworks Algorithm.

The rate of penetration (ROP) is a manifestation of drilling efficiency, and optimizing drilling parameters is an important way to improve it. To achieve a low ROP for a Permian formation in a certain oil and gas field, three single wells in this formation were selected for optimization. An improved fireworks optimization algorithm was proposed for drilling parameter optimization. We first established the objective function that predicted the ROPs for the three wells. The objective function employed a multilayer perceptron neural network as the optimization adaptation function. We then optimized four controllable parameters (weight on bit, rotary speed, pump discharge, and pump pressure) and improved the fireworks algorithm with an adaptive number of various factors. This improvement enhanced the debugging performance of the fireworks algorithm during optimization. The results indicated that the improved fireworks algorithm has significantly enhanced search performance, and the optimum ROPs for the three wells were increased by 38.55, 78.30, and 60.15%, which provides a reference for the controllable parameter setting in the area.

Fuzzy Neural Network for Studying Coupling between Drilling Parameters.

The rate of penetration (ROP) is an index used to measure drilling efficiency. However, it is restricted by many factors, and there is a coupling relationship among them. In this study, the random forest algorithm is used to sort influencing factors in order of feature importance. In this way, less influential factors can be removed. A fuzzy neural network (FNN) is applied to the field of drilling engineering for the first time, aiming at the coupling problem to predict the ROP. Fuzzification is an important part of training and realizing FNN, but research on this topic is currently lacking. In this study, K-means are used to divide the data with high similarity into a fuzzy set, which is used as the initialization parameter for the second layer of the FNN. The data of Shunbei No. 1 and 5 fault zones in Xinjiang are collected and trained. The results show that the mean value of the coefficient of determination R 2 is 0.9668 under 10 experiments, which is higher than those obtained from a back propagation neural network and multilayer perceptron particle swarm optimization methods. Therefore, the effectiveness and feasibility of the model are verified. The proposed model can improve drilling efficiency and save drilling costs.

Anatomical Variations of the Vertebral Artery: Analysis by Three-Dimensional Computed Tomography Angiography in Chinese Population.

OBJECTIVE: To analyze the anatomical variations of V3 and V2 segments of the vertebral artery in the Chinese population. METHODS: The current retrospective study was an observational, anatomical, radiological research. Between 1 January 2018 to 31 December 2019, the data of 589 continuous head-and-neck three-dimensional computed tomography angiography were observed and analyzed using the open-source software of Horos. There were 415 males and 174 females with an average age of 44.63 ± 2.5(18-74) years. The variations of the V3 segment were defined as persistent first intersegmental artery (PFIA) and paracondylar processes (PP). The variations of V2 segments were unusual vertebral artery entrance transverse foreman (UE-V2S) and midline migration (MM). The incidences of all variations were summarized and the gender, side characters were compared. RESULTS: Among the patients, 4.34% (18/415) males and 4.60% (8/174) females were with the variation of PFIA. Meanwhile, 12.29% (51/415) males and 10.92% (19/174) females were with the variation of PP. Then 18.80% (78/415) males and 16.67% (29/174) females were with UE-V2S. All the variations above were not different in genders. As for the variation of MM, 3.86% (16/415) males and 8.62% (15/174) females were identified, and the difference of genders was significant for this type of variation (P < 0.05). The differences between each side were also observed and analyzed for all variations and no differences were found. CONCLUSION: There are several variations of V3 and V2 segments of the vertebral artery are associated with the cervical surgeries, most were without differences in genders and sides, except the variation of MM.

Unilateral percutaneous kyphoplasty for lumbar spine: A comparative study between transverse process-pedicle approach and conventional transpedicular approach.

Anatomical differences of unilateral percutaneous kyphoplasty (PKP) between transverse process-pedicle approach (TPPA) and conventional transpedicular approach (CTPA) are not well discussed. To investigate the anatomical distinctions of unilateral PKP between TPPA and CTPA, we have discussed the unilateral PKP through a 3-dimensional-computed tomography database.Five hundred lumbar spines from 100 patients have been retrospectively collected and unilateral CTPA and TPPA were simulated. Distance between the entry point and the midline of the vertebral body (DEM), the puncture inclination angle (PIA), and the success rate (SR) of puncture were measured and compared.The male presented with significantly larger DEM than the female. The TPPA group presented with larger DEM than the CTPA group according to different level, the difference was 1.5 ±â€Š1.1 mm to 3.8 ±â€Š2.3 mm. The PIAs in the TPPA group were larger than that in the CTPA group. The SR including 1 side SR and bilateral SR was 72.0% in the CTPA group and 98.0% in the TPPA group. Compared with CTPA group, the SR in TPPA group was significantly higher for L1 to L4 no matter in the left, right side and female patients.The TPPA group presented with more lateral entry point, larger PIAs and higher SRs than that in the CTPA group. PKP surgery through a TPPA was safer and could provide a more symmetrical distribution of bone cement than the CTPA group.

Minimally invasive surgical techniques for the therapy of far lateral disc herniation in middle-aged and elderly patients.

To examine the clinical results of different minimally invasive techniques for the therapy of far lateral disc herniation in middle-aged and elderly patients. An endoscopic approach (percutaneous endoscopic lumbar discectomy; PELD), MIS-TLIF combined with contralateral translaminar screw (MIS-TLIF CTS), and MIS-TLIF combined with bilateral pedicle screws (MIS-TLIF BPS) were evaluated via a retrospective chart review. Data from 74 consecutive middle-aged and elderly patients with far lateral disc herniation were analyzed. All patients underwent surgery; 19 with PELD, 24 with MIS-TLIF CTS, and 31 with MIS-TLIF BPS. Clinical data included the length of the incision, duration of the operation, estimated blood loss, hospitalization time, operation cost, recurrence rate, and fusion rate. Preoperative and postoperative patient outcomes including the VAS, ODI scores and MacNab criteria were assessed and recorded. The mean follow-up time was 26.4 months (range from 14 to 46 months). Compared with the internal fixation groups, the length of the incision, duration of operation, estimated blood loss, and hospitalization time were obviously lower in the PELD group. The difference in operation cost among the three methods was statistically significant. The postoperative VAS scores for LBP and LP decreased significantly as compared with those recorded preoperatively. The postoperative ODI scores were lower than those recorded preoperatively. MacNab criteria rating excellent, good and fair results were in 27, 37 and 10 patients, respectively. Conclusion: PELD, MIS-TLIF CTS, and MIS-TLIF BPS are all effective minimally invasive techniques for the therapy of single segment far lateral lumbar disc herniation in middle-aged and elderly patients. PELD had a shorter operation time and less surgical trauma, being a less invasive and more economical method; however, there was no recurrence of disc herniation after fixation. Compared with MIS-TLIF BPS, MIS-TLIF CTS obtained a similar clinical effect and certain costs were saved.

Traumatic Facial Fractures in Children and Adolescents.

This study showed a retrospective analysis of the incidence and pattern of traumatic facial fractures in a pediatric and adolescent population (≤18 years old) in China. The authors retrospectively reviewed 154 children and adolescent who had traumatic facial fractures and who were admitted to our university-affiliated hospitals from 2005 to 2010. This study enrolled 109 males and 45 females aged 11.9 ±â€Š5.2 years old. The incidence peaked around the periods of 12 to 18 years in the male, ≤6 and 16 to 18 years in the female. The most common etiologies were motor vehicle collisions (MVCs) (60, 39.0%), followed by high fall (40, 26.0%), low fall (32, 20.8%). The most common fracture sites were mandible (78, 50.6%) and nose (33, 21.4%), followed by orbit (31, 20.1%). A total of 35 (22.7%) patients suffered neurological deficit. The patients in the 12 to 18 age range group accounted for the largest proportion of 54.5%. Fracture incidence showed peaks between the hours of 12:00 to 16:00 PM (33.7%), during the autumn season (30.5%) and on Friday to Sunday (50.0%). The most common etiology and fracture site were MVCs and mandible, respectively. Etiologies and patterns of traumatic facial fractures vary with age. Continued efforts toward injury prevention of traumatic facial fracture among the children and adolescents are warranted.

Variance-Constrained State Estimation for Complex Networks With Randomly Varying Topologies.

This paper investigates the variance-constrained state estimation problem for a class of nonlinear time-varying complex networks with randomly varying topologies, stochastic inner coupling, and measurement quantization. A Kronecker delta function and Markovian jumping parameters are utilized to describe the random changes of network topologies. A Gaussian random variable is introduced to model the stochastic disturbances in the inner coupling of complex networks. As a kind of incomplete measurements, measurement quantization is taken into consideration so as to account for the signal distortion phenomenon in the transmission process. Stochastic nonlinearities with known statistical characteristics are utilized to describe the stochastic evolution of the complex networks. We aim to design a finite-horizon estimator, such that in the simultaneous presence of quantized measurements and stochastic inner coupling, the prescribed variance constraints on the estimation error and the desired performance requirements are guaranteed over a finite horizon. Sufficient conditions are established by means of a series of recursive linear matrix inequalities, and subsequently, the estimator gain parameters are derived. A simulation example is presented to illustrate the effectiveness and applicability of the proposed estimator design algorithm.

H∞ state estimation for discrete-time neural networks with distributed delays and randomly occurring uncertainties through Fading channels.

In this paper, the H∞ state estimation problem is investigated for a class of uncertain discrete-time neural networks subject to infinitely distributed delays and fading channels. Randomly occurring uncertainties (ROUs) are introduced to reflect the random nature of the network condition fluctuations, and the channel fading phenomenon is considered to account for the possibly unreliable network medium on which the measurement signal is transmitted. A set of Bernoulli-distributed white sequences are employed to govern the ROUs and the L-th Rice fading model is utilized where channel coefficients are mutually independent random variables with certain probability density function on [0,1]. We aim to design a state estimator such that the dynamics of the estimation error is asymptotically stable while satisfying the prescribed H∞ performance constraint. By adopting the Lyapunov-Krasovskii functional and the stochastic analysis theory, sufficient conditions are established to ensure the existence of the desired state estimators and the explicit expression of such estimators is acquired. A simulation example is provided to verify the usefulness of the proposed approach.

Short-term effects of a dynamic neutralization system (Dynesys) for multi-segmental lumbar disc herniation.

PURPOSE: To determine the safety and short-term curative effects of internal fixation using a dynamic neutralization system (Dynesys) for multi-segmental lumbar disc herniation (ms-LDH) with the control group treated by posterior lumbar interbody fusion (PLIF). METHODS: Forty-five patients with ms-LDH were selected as study group treated with Dynesys and 40 patients as control group with PLIF. The surgical efficacy was evaluated by comparing the visual analogue scale (VAS) scores, the Oswestry Disability Index (ODI) scores and the ROMs of the adjacent segment before and after surgery. The postoperative complications related to the implants were identified. RESULTS: All patients were followed up for an average duration of over 30 months. Dynesys stabilization resulted in significantly higher preservation of motion at the index level (p < 0.001), and significantly less (p < 0.05) hypermobility at the adjacent segments. VAS for back and leg pain and ODI improved significantly (p < 0.05) with both the methods, but there was no significant difference between the groups. CONCLUSIONS: The non-fusion fixation system Dynesys is safe and effective regarding short-term curative effects for the treatment of ms-LDH.

Synthesis and characterization of mixed-valence manganese fluorophosphate and analogues with clathrate-like structures: Mn(III)6F12(PO3(OH))8[Na8(Kx(H3O)4-x(H2O)2)M(IV)(OH)6] (M(IV) = Mn, Ti, Ge).

A novel, mixed- and high-valence manganese (Mn(3+)/Mn(4+)) fluorophosphate, Mn(III)6F12(PO3(OH))8[Na8(Kx(H3O)4-x(H2O)2)Mn(IV)(OH)6] (denoted as MN), has been prepared via a water-deficient hydrothermal route with phosphoric acid as the sole solvent. This compound features a cubic three-dimensional open-framework structure built from corner-sharing [Mn(III)O4F2] octahedra and [HPO4] groups, which encapsulates a clathrate-like "guest cluster" of Na8(Kx(H3O)4-x(H2O)2)Mn(IV)(OH)6. The guest cluster is architecturally composed of a [Mn(IV)(OH)6] octahedron in a cubic cage of Na(+) cations, which in turn is surrounded by an octahedral arrangement of K(+)/H2O ions, resulting in an unprecedented octahedral @ cubic @ octahedral @ cubic arrangement (OCOC). The +4 oxidation state of Mn in the guest cluster has been confirmed by the synthesis of isotypic Ti- and Ge- analogues (denoted as TI and GE) using TiO2 and GeO2 as the replacement for MnO2 in the starting materials. The compounds MN, TI and GE are not stable in aqueous solution and are peeled off layer-by-layer after the absorption of water. This report provides a new route for the synthesis of mixed- and high-valence manganese phosphates that cannot be produced by conventional hydrothermal methods.

Meta analysis of olfactory ensheathing cell transplantation promoting functional recovery of motor nerves in rats with complete spinal cord transection.

OBJECTIVE: To evaluate the effects of olfactory ensheathing cell transplantation on functional recovery of rats with complete spinal cord transection. DATA SOURCES: A computer-based online search of Medline (1989-2013), Embase (1989-2013), Cochrane library (1989-2013), Chinese Biomedical Literature Database (1989-2013), China National Knowledge Infrastructure (1989-2013), VIP (1989-2013), Wanfang databases (1989-2013) and Chinese Clinical Trial Register was conducted to collect randomized controlled trial data regarding olfactory ensheathing cell transplantation for the treatment of complete spinal cord transection in rats. SELECTION CRITERIA: Randomized controlled trials investigating olfactory ensheathing cell transplantation and other transplantation methods for promoting neurological functional recovery of rats with complete spinal cord transection were included in the analysis. Meta analysis was conducted using RevMan 4.2.2 software. MAIN OUTCOME MEASURES: Basso, Beattie and Bresnahan scores of rats with complete spinal cord transection were evaluated in this study. RESULTS: Six randomized controlled trials with high quality methodology were included. Meta analysis showed that Basso, Beattie and Bresnahan scores were significantly higher in the olfactory ensheathing cell transplantation group compared with the control group (WMD = 3.16, 95% CI (1.68, 4.65); P < 0.00001). CONCLUSION: Experimental studies have shown that olfactory ensheathing cell transplantation can promote the functional recovery of motor nerves in rats with complete spinal cord transection.

Tranexamic acid reduces postoperative blood loss of degenerative lumbar instability with stenosis in posterior approach lumbar surgery: a randomized controlled trial.

STUDY DESIGN: This study is randomized controlled trial. PURPOSE: To evaluate the effect of tranexamic acid (TXA) on reducing postoperative blood loss in posterior approach lumbar surgery for degenerative lumbar instability with stenosis. METHODS: Sixty patients with degenerative lumbar instability with stenosis were randomized into TXA and control groups, receiving 15 mg/kg body weight of TXA or placebo (0.9 % Sodium chloride solution) intravenously, respectively, before the skin incision was made. The operation of pedicle screw system fixation was performed for all patients, and then selective laminectomy and posterior lumbar interbody fusion (PLIF) were carried out. Intraoperative and postoperative blood loss were compared between the two groups. And the complication of TXA was also investigated. RESULTS: There were no statistically significant differences between the TXA and control groups in terms of age, sex, body mass index, and operation time. There was no significantly difference in intraoperative blood loss between the two groups. However, in the TXA group, postoperative blood loss was significantly lower than that in the control group (13.0 %). Especially, postoperative blood loss during the first 12 h was reduced by 29.9 % as compared to the control group. There were no thromboembolic events or other complications occurred in either group. CONCLUSIONS: Preoperative single-dose TXA can significantly reduce postoperative blood loss in posterior approach lumbar surgery, and there were no significant side effects.

Kappa opioid receptor antagonist and N-methyl-D-aspartate receptor antagonist affect dynorphin-induced spinal cord electrophysiologic impairment.

The latencies of motor- and somatosensory-evoked potentials were prolonged to different degrees, and wave amplitude was obviously decreased, after injection of dynorphin into the rat subarachnoid cavity. The wave amplitude and latencies of motor- and somatosensory-evoked potentials were significantly recovered at 7 and 14 days after combined injection of dynorphin and either the kappa opioid receptor antagonist nor-binaltorphimine or the N-methyl-D-aspartate receptor antagonist MK-801. The wave amplitude and latency were similar in rats after combined injection of dynorphin and nor-binaltorphimine or MK-801. These results suggest that intrathecal injection of dynorphin causes damage to spinal cord function. Prevention of N-methyl-D-aspartate receptor or kappa receptor activation lessened the injury to spinal cord function induced by dynorphin.

Analysis of caffeic acid derivatives from Osmanthus yunnanensis using electrospray ionization quadrupole time-of-flight mass spectrometry.

A series of six caffeic acid derivatives (1-6) in Osmanthus yunnanensis were investigated by electrospray quadrupole time-of-flight tandem mass spectrometry (ESI-QToF-MS/MS) in both negative- and positive-ion modes. High-quality MS/MS spectra of [M + H](+) are generated from high-abundance protonated parent ions obtained by addition of ammonium chloride to the solutions. Fragmentation mechanisms of [M - H](-) and [M + H](+) precursor ions were proposed and elemental compositions of most of the product ions were confirmed on the basis of the high-resolution ESI-collision-induced dissociation (CID)- MS/MS spectra. It was found that the fragment ions at m/z 179, m/z 161, m/z 135 and m/z 134 in negative-ion mode and at m/z 163, m/z 145 and m/z 135 in positive mode should be the characteristic ions of caffeic acid. In addition, the radical fragment ions with high abundance were observed for many caffeic acid derivatives especially for 4. The structural elements of unknown compounds 7 and 8 were tentatively identified on based on tandem mass spectra of known ones.

Analysis of epipolythiodioxopiperazines in fungus Chaetomium cochliodes using HPLC-ESI-MS/MS/MS.

A series of epipolythiodioxopiperazines in the fungus Chaetomium cochliodes was investigated using reversed-phase liquid chromatography with diode array detection and electrospray quadrupole time-of-flight-type tandem mass spectrometry in the positive ion mode. The fragmentation of protonated molecular ions including low-abundance parent ions, [M+H]+ for five known epipolythiodioxopiperazines, dethiotetra(methylthio)chetomin, chaetocochins A-C, and chetomin, was carried out using low-energy collision-induced electrospray ionization tandem spectrometry. It was found that McLafferty rearrangements occurred in the CID processes and produced a complementary pair of characteristic fragment ions containing piperazine rings (fused and unfused), especially to determine the number of S atoms on each ring. The fragmentation differential between [M+H]+ and [M+Na]+ was uncovered. Complementary fragmentation information obtained from [M+H]+ and [M+Na]+ precursor ions is especially valuable for rapid identification of epipolythiodioxopiperazines. A likely known compound, possibly related to chetoseminudin A, and three new species of epipolythiodioxopiperazines from the fungus C. cochliodes were identified or tentatively characterized based on tandem mass spectra of known ones.

Electrospray tandem mass spectrometry of epipolythiodioxopiperazines.

Low-energy collision-induced electrospray ionization tandem mass spectrometry ESI-CID-MS/MS (in the positive ion mode) was used for the structural characterization of a series of five representative epioplythiodioxopipreazines: dethiotetra(methylthio)chemotin, chaetocochins A, B and C, and chemotin isolated from the fungus Chaetomium cochliodes. The fragmentation pathways were elucidated by ESI-IT-MS(n). The elemental compositions of most of the product ions were confirmed by low-energy ESI-CID-QTOF-MS/MS analyses. The loss of the S(2) molecule seems always to be the first when the S--S bond is present. The loss of 77 Da corresponding to the loss of the [CH(3)SCH(2)O]' radical was diagnostic for chaetocochins A and B, in which the two piperazines rings are linked by an acetal group. It was found that a McLafferty rearrangement plays a significant role in the skeleton fragmentation of theses series of studied complex multicyclic piperazine compounds. This MacLafferty rearrangement affords the product ions at m/z 416 and 400, containing the two piperazine rings belonging to the epipolythiodioxopipreazines. In addition, the pentacyclic rearrangement involving the loss of the SMe(.) radical seems to occur in the presence of the unfused ring. Finally the product ions at m/z 635 and 591 seem to be the characteristic ions for chaetocochin A.