Conventional MA Research Articles

Comprehensive database and individual patient data meta-analysis of randomised controlled trials on psychotherapies reducing suicidal thoughts and behaviour: study protocol

IntroductionPsychotherapy may reduce suicidal thoughts and behaviour, but its effectiveness is not well examined. Furthermore, conventional meta-analyses are unable to test possible effects of moderators affecting this relationship. This protocol...

Techniques d’alignement cinématique versus conventionnel des prothèses totales de hanche : étude cas témoin

BackgroundResidual complications of conventionally implanted hip components have only been partially reduced by improved implant design and higher surgical precision, and their occurrence is poorly predicted by the radiographic standing/supine cup orientation. This has raised awareness that conventional techniques may not aim for the correct component orientation target, and the lumbo-pelvic kinematics, which influence the functional acetabular orientation, may be of interest to further improve THA clinical outcomes. This has led to the development of the Lumbo-Pelvic kinematic alignment (KA) technique for THA that aims to anatomically position and kinematically align hip implants (acetabular and femoral, total and resurfacing components), in order to optimise prosthetic hip biomechanics and hopefully improve prosthetic function, patient satisfaction, and components’ lifespan. Therefore, we conducted a case control investigation to assess the early-term safety and efficacy of this new technique by answering the following questions: does the KA technique for THA: (1) better restore the native hip anatomy, (2) generate a different radiographic supine cup position, and (3) improve clinical outcomes in comparison to the conventional mechanical alignment technique? HypothesesUsing KA technique allows there is no statistically significant difference between the pre to postoperative differential for acetabular medial and vertical offsets, femoral offset, and leg length. MethodsWe led a case-control retrospective study with prospectively collected clinical data. Forty-one consecutive unselected KA-THAs performed with manual instrumentation were paired with 41 mechanically aligned THAs. The 1-year clinical outcomes and radiographical measurements were compared. ResultsCompared to the mechanical alignment technique, the KA technique resulted in a more anatomical restoration of the prosthetic hip centre of rotation with a lower delta pre- to post-operative horizontal acetabular offset (1.47mm for KA vs. −5.1mm for MA, p=0.001), and with 74% of KA vs. 50% of MA cups (p=0.044) being within 15% of native anatomy for the horizontal acetabular offset. In addition, the KA technique resulted in a higher cup anteversion (22̊±7̊ vs. 15̊±8̊, p<0.001) but similar cup inclination (41̊±6̊ vs. 42̊±7̊, p=0.25), a similar proportion of cups within the Lewinnek zone (65% vs. 70%, p=0.8), similar excellent functional outcomes (delta Oxford score pre- to follow-up of 24.3 and 23.5 points for KA and MA groups, respectively, p=0.88), similar patient satisfaction scores of 95.4/100 and 89.5/100 for KA and MA groups, respectively, and the same absence of aseptic complications. ConclusionThe KA technique for THA has been demonstrated to be safe, efficacious, and not inferior to the conventional MA technique at early-term. As the concept of the KA technique for THA is only at an early stage, its influence on mid to long-term clinical outcomes remains to be determined and further refinements of the concept are yet to be made. Level of evidenceIII; case-control retrospective study.

Kinematic alignment versus conventional techniques for total hip arthroplasty: A retrospective case control study

BackgroundResidual complications of conventionally implanted hip components have only been partially reduced by improved implant design and higher surgical precision, and their occurrence is poorly predicted by the radiographic standing/supine cup orientation. This has raised awareness that conventional techniques may not aim for the correct component orientation target, and the lumbo-pelvic kinematics, which influences the functional acetabular orientation, may be of interest to further improve THA clinical outcomes. This has led to the development of the Lumbo-Pelvic kinematic alignment (KA) technique for THA that aims to anatomically position and kinematically align hip implants (acetabular and femoral, total and resurfacing components), in order to optimise prosthetic hip biomechanics and hopefully improve prosthetic function, patient satisfaction, and components’ lifespan. Therefore, we conducted a case control investigation to assess the early-term safety and efficacy of this new technique by answering the following questions: does the KA technique for THA: (1) better restore the native hip anatomy, (2) generate a different radiographic supine cup position, and (3) improve clinical outcomes in comparison to the conventional mechanical alignment technique? HypothesesUsing KA technique allows there is no statistically significant difference between the pre to postoperative differential for acetabular medial and vertical offsets, femoral offset, and leg length. MethodsWe led a case control retrospective study with prospectively collected clinical data. Forty-one consecutive unselected KA-THAs performed with manual instrumentation were paired with 41 mechanically aligned THAs. The 1-year clinical outcomes and radiographical measurements were compared. ResultsCompared to the mechanical alignment technique, the KA technique resulted in a more anatomical restoration of the prosthetic hip centre of rotation with a lower delta pre- to post-operative horizontal acetabular offset (1.47mm for KA versus −5.1mm for MA, p=0.001), and with 74% of KA versus 50% of MA cups (p=0.044) being within 15% of native anatomy for the horizontal acetabular offset. In addition, the KA technique resulted in a higher cup anteversion (22°±7° vs 15°±8°, p<0.001) but similar cup inclination (41°±6° vs. 42°±7°, p=0.25), a similar proportion of cups within the Lewinnek zone (65% vs. 70%, p=0.8), similar excellent functional outcomes (delta Oxford score pre- to follow-up of 24.3 and 23.5 points for KA and MA groups, respectively, p=0.88), similar patient satisfaction scores of 95.4/100 and 89.5/100 for KA and MA groups, respectively, and the same absence of aseptic complications. ConclusionThe KA technique for THA has been demonstrated to be safe, efficacious, and not inferior to the conventional MA technique at early-term. As the concept of the KA technique for THA is only at an early stage, its influence on mid to long-term clinical outcomes remains to be determined and further refinements of the concept are yet to be made. Level of evidenceIII; case-control retrospective study.

Mechanical alignment technique for TKA: Are there intrinsic technical limitations?

BackgroundMechanically aligned (MA) total knee arthroplasty (TKA) is affected by disappointing functional outcomes in spite of the recent improvements in surgical precision and implant designs. This might suggest the existence of intrinsic technical limitations. Our study aims to compare the prosthetic and native trochlear articular surfaces and to estimate the extent of collateral ligament imbalance, which is technically uncorrectable by collateral ligament release when TKA implants are mechanically aligned. Study hypothesisConventional MA technique generates a high rate of prosthetic overstuffing of the distal groove, distal lateral trochlear facet and distal lateral femoral condyle (Hypothesis 1), and technically uncorrectable collateral ligament imbalance (hypothesis 2)? Disregarding the distal femoral joint line obliquity (DFJLO) when performing femoral cuts explains distal lateral femoral prosthetic stuffing and uncorrectable imbalance (hypothesis 3)? MethodsTwenty patients underwent a conventional MA TKA. Pre-operative MRI-based 3D knee models were generated and MA TKA was simulated. Native and prosthetic trochlear articular surfaces were compared using in-house analysis software. Following the automatic determination by the planning software of the size of the extension and flexion gaps, an algorithm was applied to balance the gaps and the frequency and amplitude of technically uncorrectable knee imbalance were estimated. ResultsThe conventional MA technique generates a significant slight distal lateral femoral prosthetic overstuffing (mean 0.6mm, 0.8mm, 1.25mm for the most distal lateral facet point, groove, and at the most distal point of lateral femoral condyle, respectively) and a high rate of type 1 and 2 uncorrectable knee imbalance (30% and 40%, respectively). The incidence of distal lateral prosthetic overstuffing (trochlea and condyle) and uncorrectable knee imbalance were strongly to very strongly correlated with the DFJLO (r=0.53 to 0.89). ConclusionConventional MA technique for TKA generates frequent lateral distal femoral prosthetic overstuffing and technically uncorrectable knee imbalance secondary to disregarding the DFJLO when adjusting the femoral component frontal and axial rotations, respectively. Level of evidencelevel 4.

Application of Non-Orthogonal Multiple Access in LTE and 5G Networks

As the latest member of the multiple access family, non-orthogonal multiple access (NOMA) has been recently proposed for 3GPP LTE and is envisioned to be an essential component of 5G mobile networks. The key feature of NOMA is to serve multiple users at the same time/frequency/ code, but with different power levels, which yields a significant spectral efficiency gain over conventional orthogonal MA. The article provides a systematic treatment of this newly emerging technology, from its combination with MIMO technologies to cooperative NOMA, as well as the interplay between NOMA and cognitive radio. This article also reviews the state of the art in the standardization activities concerning the implementation of NOMA in LTE and 5G networks.

Adjustment for reporting bias in network meta-analysis of antidepressant trials

BackgroundNetwork meta-analysis (NMA), a generalization of conventional MA, allows for assessing the relative effectiveness of multiple interventions. Reporting bias is a major threat to the validity of MA and NMA. Numerous methods are available to assess the robustness of MA results to reporting bias. We aimed to extend such methods to NMA.MethodsWe introduced 2 adjustment models for Bayesian NMA. First, we extended a meta-regression model that allows the effect size to depend on its standard error. Second, we used a selection model that estimates the propensity of trial results being published and in which trials with lower propensity are weighted up in the NMA model. Both models rely on the assumption that biases are exchangeable across the network. We applied the models to 2 networks of placebo-controlled trials of 12 antidepressants, with 74 trials in the US Food and Drug Administration (FDA) database but only 51 with published results. NMA and adjustment models were used to estimate the effects of the 12 drugs relative to placebo, the 66 effect sizes for all possible pair-wise comparisons between drugs, probabilities of being the best drug and ranking of drugs. We compared the results from the 2 adjustment models applied to published data and NMAs of published data and NMAs of FDA data, considered as representing the totality of the data.ResultsBoth adjustment models showed reduced estimated effects for the 12 drugs relative to the placebo as compared with NMA of published data. Pair-wise effect sizes between drugs, probabilities of being the best drug and ranking of drugs were modified. Estimated drug effects relative to the placebo from both adjustment models were corrected (i.e., similar to those from NMA of FDA data) for some drugs but not others, which resulted in differences in pair-wise effect sizes between drugs and ranking.ConclusionsIn this case study, adjustment models showed that NMA of published data was not robust to reporting bias and provided estimates closer to that of NMA of FDA data, although not optimal. The validity of such methods depends on the number of trials in the network and the assumption that conventional MAs in the network share a common mean bias mechanism.

Quick, “Imputation-free” meta-analysis with proxy-SNPs

BackgroundMeta-analysis (MA) is widely used to pool genome-wide association studies (GWASes) in order to a) increase the power to detect strong or weak genotype effects or b) as a result verification method. As a consequence of differing SNP panels among genotyping chips, imputation is the method of choice within GWAS consortia to avoid losing too many SNPs in a MA. YAMAS (Yet Another Meta Analysis Software), however, enables cross-GWAS conclusions prior to finished and polished imputation runs, which eventually are time-consuming.ResultsHere we present a fast method to avoid forfeiting SNPs present in only a subset of studies, without relying on imputation. This is accomplished by using reference linkage disequilibrium data from 1,000 Genomes/HapMap projects to find proxy-SNPs together with in-phase alleles for SNPs missing in at least one study. MA is conducted by combining association effect estimates of a SNP and those of its proxy-SNPs. Our algorithm is implemented in the MA software YAMAS. Association results from GWAS analysis applications can be used as input files for MA, tremendously speeding up MA compared to the conventional imputation approach. We show that our proxy algorithm is well-powered and yields valuable ad hoc results, possibly providing an incentive for follow-up studies. We propose our method as a quick screening step prior to imputation-based MA, as well as an additional main approach for studies without available reference data matching the ethnicities of study participants. As a proof of principle, we analyzed six dbGaP Type II Diabetes GWAS and found that the proxy algorithm clearly outperforms naïve MA on the p-value level: for 17 out of 23 we observe an improvement on the p-value level by a factor of more than two, and a maximum improvement by a factor of 2127.ConclusionsYAMAS is an efficient and fast meta-analysis program which offers various methods, including conventional MA as well as inserting proxy-SNPs for missing markers to avoid unnecessary power loss. MA with YAMAS can be readily conducted as YAMAS provides a generic parser for heterogeneous tabulated file formats within the GWAS field and avoids cumbersome setups. In this way, it supplements the meta-analysis process.

Is the Chinese stock market really inefficient?

Groenewold et al. (2004) documented that the Chinese stock market is inefficient. In this paper, we revisit the efficiency problem of the Chinese stock market using time-series model based trading rules. Our paper distinguishes itself from previous studies in several aspects. First, while previous studies concentrate on the viability of linear forecasting techniques, we evaluate the profitability of the forecasts of the self-exciting threshold autoregressive model (SETAR), and compare it with the conventional linear AR and MA trading rules. Second, the findings of market inefficiency in earlier studies mainly rest on the statistical significance of the autocorrelation or regression coefficients. In contrast, this paper directly examines the profitability of various trading rules. Third, our sample covers an extensive period of 1991–2010. Sub-sample analysis shows that positive returns mainly concentrate in the pre-SOE reform period, suggesting that China's stock market has become more efficient after the reform.

A new model for the Indochina and South China collision during the Late Permian to the Middle Triassic

A comparative analysis of Indochina and South China during the Early Paleozoic indicates the former may be extended to include North Vietnam, part of the Qinzhou tectonic zone and southern Hainan Island. These three regions were traditionally regarded as parts of South China separated from Indochina by the Song Ma suture in Central-North Vietnam. A new suture, called the Dian-Qiong suture, is proposed here, approximately along the southern margin of the present Nanpanjiang basin. This suture is linked to its eastern counterpart in Hainan Island through a NNE-trending dextral transform fault zone along the eastern margin of the Nanpanjiang basin. The conventional Song Ma suture originally constitutes its western extension and was translated to its present location by sinistral displacement along the Red River Fault Zone during the Tertiary. Upper Paleozoic deep-water turbidites and associated mid-oceanic ridge basalts along the suture in the Nanpanjiang basin illustrate a coeval ocean between Indochina and South China. The ocean was consumed by south-directed subduction beneath Indochina during the Late Permian to the Middle Triassic. This suture zone was finally re-shaped by the indentation between the active margin of Indochina and the irregular passive continental margin of South China during the Late Triassic as well as displacement along the Red River fault zone during the Cenozoic.

High-temperature metal–organic magnets

For over two decades there have been intense efforts aimed at the development of alternatives to conventional magnets, particularly materials comprised in part or wholly of molecular components. Such alternatives offer the prospect of realizing magnets fabricated through controlled, low-temperature, solution-based chemistry, as opposed to high-temperature metallurgical routes, and also the possibility of tuning magnetic properties through synthesis. However, examples of magnetically ordered molecular materials at or near room temperature are extremely rare, and the properties of these materials are often capricious and difficult to reproduce. Here we present a versatile solution-based route to a new class of metal-organic materials exhibiting magnetic order well above room temperature. Reactions of the metal (M) precursor complex bis(1,5-cyclooctadiene)nickel with three different organics A-TCNE (tetracyanoethylene), TCNQ (7,7,8,8-tetracyanoquinodimethane) or DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone)--proceed via electron transfer from nickel to A and lead to materials containing Ni(II) ions and reduced forms of A in a 2:1 Ni:A ratio--that is, opposite to that of conventional (low Curie temperature) MA(2)-type magnets. These materials also contain oxygen-based species within their architectures. Magnetic characterization of the three compounds reveals spontaneous field-dependent magnetization and hysteresis at room temperature, with ordering temperatures well above ambient. The unusual stoichiometry and striking magnetic properties highlight these three compounds as members of a class of stable magnets that are at the interface between conventional inorganic magnets and genuine molecule-based magnets.

00/01994 Photoinduced FT-IR spectroscopy and CW-photocurrent measurements of conjugated polymers and fullereness blended into a conventional polymer ma

00/01994 Photoinduced FT-IR spectroscopy and CW-photocurrent measurements of conjugated polymers and fullereness blended into a conventional polymer ma

溶射法によるSi-Ge系熱電皮膜の作製と特性改善

For the energy saving, thermoelectric conversion materials (TEC) are attracting much attention. However, the conversion efficiency of thermoelectric materials is remarkably low in the single element compared to the other conventional power generations. Therefore, the thermoelectric elements have to be composed as the thermo-module in which the huge numbers of the elements are connected. In many configurations of TEC, the thick coating may be advantageous in joining or laminating.The plasma spraying, which was characterized to be a high deposition rate process, was used to fabricate the thick coating of the thermoelectric elements. We previously reported that β-FeSi2 thermoelectric coating could be fabricated by plasma spraying, and the thermoelectric property was the same as the bulk material.In this study, the Si-Ge system was focused because of its excellent thermoelectric property in a high temperature range. Moreover, the spraying and some treatments were applied for improving the thermoelectric properties with the aim of clarifying the conditions to fabricate high performance Si-Ge TEC coating.The results obtained are summerized as follows;(1) MA-spraying process could be applied for the fabrication of SiGe thermoelectric coating.(2) The boundary at the joined layers in the case of FGM coating was diminished by polishing the coating surface before spraying the next layer. Joint type FGM coating of Si-Ge doped with different fractions of P could be fabricated by plasma spraying.(3) The thermoelectric coating made from the granulated powder had a quite fine and dense microstructure. The resistivity of the coating decreased to one-tenth of coating made from the conventional MA powder, and consequently its power factor reached the level over than that of the sintered body.

Utility of low mA 1.5 pitch helical versus conventional high mA abdominal ct

The objective of this study was to evaluate the utility of a low mA 1.5 pitch helical versus conventional high mA conventional technique in abdominal computed tomography (CT). Twenty-five patients who had both a conventional high mA (>300) and a 1.5 pitch low mA (80–125) helical CT within 3 months were selected for inclusion in the study. Patients were excluded who had a significant change in pathology between the two studies. The other parameters (injection rate, contrast type and volume, and filming window/level) were constant. The studies were randomized and blinded to five separate experienced readers who graded the studies by a variety of normal anatomical structures and pathological criteria. Overview questions also assessed noise, resolution, contrast, and overall quality. The abdominal wall/retroperitoneum and hiatal hernias were statistically better visualized on the conventional high mA studies. However, for all other normal anatomical and pathological sites, there was equivalent or better visualization on the helical versus the conventional CT examinations. The resolution of the helical studies was graded statistically better than the high mA conventional CT scans as was the amount of noise present on the images. While there was some advantage for conventional high mA CT with respect to contrast enhancement and low contrast sensitivity, these differences were not statistically significant. It appears from the data of this study that a low mA technique in evaluating the abdomen may be a useful option in performing routine abdominal CT. The radiation dose savings to the patient is significant and there appears to be little degradation of image quality using a low mA 1.5 helical versus mA conventional CT technique.

Order Statistical Filtering: a Robust Method of Noise Estimation

The detection of a narrowband signal in a sonar environment with spatially uncorrelated white noise depends very much on the accuracy in estimating the noise power so that a threshold can be correctly fixed. The conventional MA method presents a large bias when operated in an environment where interfering signals exist in the neighborhood. Various types of nonlinear methods based on the use of order statistics are introduced and analyzed and are found to be much more robust.