Asymmetric Funnel Research Articles

Baseline right ventricular-pulmonary artery uncoupling and mortality following transcatheter aortic valve replacement: a meta-analysis

Abstract Background In severe aortic stenosis (AS) patients, elevated left-sided filling pressures can lead to pulmonary hypertension and right ventricular (RV) systolic dysfunction. These conditions signal advanced disease and predict poor outcomes in transcatheter aortic valve replacement (TAVR) cases. However, recent studies indicate potential recovery post-TAVR, with improved prognosis. The newly recognized index, RV to pulmonary artery (RV-PA) coupling, reflects the RV's ability to handle pulmonary afterload and is associated with adverse outcomes. Purpose This study aimed to delineate the prognostic role of baseline RV-PA uncoupling in patients undergoing TAVR. Methods We conducted a systematic literature search for studies assessing RV-PA coupling indices at baseline in patients undergoing TAVR. We recorded the year of publication, method of RV-PA assessment, the proposed cutoffs, patients’ age-sex, and follow-up duration. The primary outcome of interest was all-cause mortality at maximal follow-up and the adjusted hazard ratios of RV-PA uncoupling for all-cause mortality were extracted. Pooling of the hazard ratios was conducted according to a random effects model. I2 was chosen as the measure of between-study heterogeneity, with values exceeding 50% being significant. Results We identified a total of 316 studies, of which 5 were ultimately selected for data extraction and inclusion in the meta-analysis after screening of title/abstract/full-text. All but one study utilized the Tricuspid Annular Plane Systolic Excursion/Pulmonary artery systolic pressure (TAPSE/PASP) as the method of RV-PA assessment. The mean age of the participants across the studies was approximately 81 years old, with a balanced male:female ratio. The median follow-up duration was 23 months (range: 6-40 months). According to the results of the meta-analysis, the presence of baseline RV-PA uncoupling was associated with a 2.8-fold increased risk of all-cause mortality at maximal follow-up (Figure). Significant between-study heterogeneity was detected. An asymmetric funnel plot was inspected, indicative of publication bias (Egger’s test intercept: 6.76, 95% confidence interval 5.07-8.44, p=0.004). The results, although attenuated, remained significant even after a trim-and-fill analysis (3 studies added, hazard ratio: 1.27, 95% confidence interval: 0.03-2.51, p=0.04). Furthermore, the results were unaffected following a sensitivity analysis with the leave-one-out method. Conclusion This meta-analysis suggests that baseline RV-PA uncoupling prior to TAVR is associated with all-cause mortality and it could serve as an imaging biomarker of prognosis in this patient population.Figure

Design and performance of a dual stage asymmetric ion funnel interface

A dual-stage asymmetric ion funnel (DAIF) interface has been designed to remove the bottleneck in ion transmission from atmospheric ionization to the vacuum chamber. This leads to increased sensitivity and improved performance of the mass spectrometer. Both ion funnels are asymmetrically constructed, with a precisely calculated 7 mm radial offset in the ion path. This accelerates the separation of ions from the neutral stream, reduces contamination, and enhances the flow field and vacuum system. The performance of the DAIF interface was investigated through numerical simulations and experimental tests, utilizing the Hexin API-5000 TOFMS as our experimental platform. The results indicate that the asymmetric ion funnel has a powerful desolvation capability, achieving a high transmission efficiency of 87.9%. The novel DAIF interface enhances sensitivity by an order of magnitude. In addition, the robustness of the instrument can be improved by efficiently removing neutral molecules and contaminants from the DAIF. These features make DAIF suitable for various MS systems and ionizations.

Stem cell therapy for premature ovarian insufficiency: a systematic review and meta-analysis of animal and clinical studies.

The aim of this systematic review and meta-analysis is to evaluate the efficacy of stem cell therapy in mouse models of POI and patients with POI. The PubMed, Web of Science, and Embase databases were searched from inception to February 2022 for relevant animal and clinical studies. The reference lists of the included reviews were manually searched to identify additional eligible studies. Data were independently extracted by two investigators, and disagreements were resolved by discussion. SYRCLE's risk of bias tool and the MINORS tool were used to assess the quality of animal and clinical studies by two independent investigators. All statistical analyses were conducted using Review Manager 5.3 software. A total of twenty animal studies and six clinical studies were included in this meta-analysis. In animal studies, the results showed that stem cells could improve hormone levels, follicle count, estrous cycle and pregnancy outcome. For hormone levels, stem cells increased serum E2 and AMH levels and decreased serum FSH and LH levels compared with the control group (serum E2 level: SMD: 5.05, 95% CI 4.21-5.90, P < 0.00001; serum AMH level: SMD: 4.42, 95% CI 3.06-5.79, P < 0.00001; serum FSH level: SMD: -3.79, 95% CI -4.87 to - 2.70, P < 0.00001; serum LH level: SMD: -1.31, 95% CI -1.65 to -0.96, P < 0.00001). All follicle counts, except for the antral follicle count, were significantly changed compared with the control group. (primordial follicle count: SMD: 4.61, 95% CI 3.65-5.56, P < 0.00001; primary follicle count: SMD: 3.35, 95% CI 1.08-5.63, P = 0.004; secondary follicle count: SMD: 3.23, 95% CI 1.92-4.55, P < 0.00001; total follicle count: SMD: 4.84, 95% CI 2.86-6.83, P < 0.00001; oocyte count: SMD: 7.56, 95% CI 5.92-9.20, P < 0.00001; atretic follicle count: SMD: -1.79, 95% CI -2.59 to -1.00, P < 0.00001). For the estrous cycle, stem cell therapy increased the number of estrous cycles (WMD: 2.72, 95% CI 2.07-3.37, P < 0.00001) and decreased the duration of the estrous cycle (WMD: -1.26, 95% CI -1.84 to -0.69, P < 0.0001) compared with the control group. For pregnancy outcomes, stem cell therapy increased the fertility rate (RR: 3.00, 95% CI 1.74-5.17, P < 0.0001) and litter size (WMD: 3.82, 95% CI 0.36-7.28, P = 0.03) compared with the control group. In animal studies, the asymmetric funnel plot of serum E2 and FSH levels indicated the possibility of publication bias. Unpublished and negative studies may be the source of publication bias. In clinical studies, the results showed that stem cell therapy could decrease serum FSH level (MD: -30.32, 95% CI -59.03 to -1.01, P = 0.04) and increase AFC (MD: 1.07, 95% CI 0.70-1.43, P < 0.00001), pregnancy rate (RD: 0.19, 95% CI 0.04-0.34, P = 0.01) and live birth rate (RD: 0.19, 95% CI 0.07-0.31, P = 0.001) in POI patients. In addition, there was no significant difference in menstrual function regained (RD: 0.22, 95% CI -0.03-0.46, P = 0.09), oocytes retrieved (MD: 1.00, 95% CI -0.64-2.64, P = 0.23) and embryos (MD: 0.80, 95% CI -0.15-1.76, P = 0.10) between different groups. This meta-analysis suggested that stem cell therapy might be effective in POI mouse models and patients and could be considered a potential treatment to restore fertility capability in POI patients.

An experimental study on casing perforation erosion during sand fracturing

A sand-fracturing casing perforation erosion experimental device was designed to explore the casing perforation erosion behavior under different working conditions in the study. The influences of different factors on the casing perforation erosion mechanism were investigated based on macro-scale observations and SEM images. The serious perforation erosion occurred in the direction of the flow inlet and led to asymmetric funnel. The influences of various parameters on the perforation expansion rate were ranked according to the following order: sand-passing quantity of perforation > pump displacement > sand concentration > proppant size. Under a low sand concentration, the erosion effect of proppant particles on casing perforations was mainly caused by cutting and ploughing. Under a high sand concentration, shallow craters and brittle cracking were increased. The findings can guide the control of casing perforation erosion and improve the understanding of the perforation target erosion wear mechanism of the solid-liquid two-phase flow.

Dynamical analysis and accelerated adaptive backstepping funnel control for dual-mass MEMS gyroscope under event trigger

This paper investigates an adaptive backstepping funnel control scheme with an event-triggered mechanism for a chaotic dual-mass Micro-Electro-Mechanical Systems (MEMS) gyroscope. The mathematical model of the dual-mass micro-gyroscope is first developed based on a mutual mechanical coupling. Then, its inherent nonlinear characteristics under different spring and coupling coefficients, all of which have noticeable impacts on the system sensitivity, are fully examined through phase and Lyapunov exponent diagrams. In order to methodically address the control problem involving the uncertainty, the slow convergence, the constraint violation, the “item explosion” and the communication resource waste, an accelerated adaptive backstepping funnel controller is proposed by combining the type-2 sequential fuzzy neural network (T2SFNN), the speed function, the asymmetric funnel boundaries, the accelerated exponential integral tracking differentiator (AEITD) and the event-triggered mechanism. The recommended scheme not only well resolve the above issues, but also guarantee the prescribed performance requirements and the boundedness of all signals in closed-loop system. Finally, the effectiveness of the control scheme is substantiated through several simulated results.

Use of Computed Tomography of the Head in Patients With Acute Atraumatic Altered Mental Status

The usefulness of computed tomography of the head (CTH) in patients with acute-onset atraumatic altered mental status (AMS) is poorly understood, but use in these patients remains high. To evaluate the use of CTH (event rate) in patients with AMS and the positive outcome event rate of the performed CTH studies. The PubMed/MEDLINE, PubMed Central, Embase, and CINAHL databases were searched using predefined Boolean parameters. All studies that met inclusion criteria until January 31, 2022, were included. Randomized clinical trials and observational, cohort, and case-control studies were included. Conference abstracts, reviews, letters, case reports, case series, systematic literature, and meta-analyses were excluded. The systematic literature review was performed per Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Data were independently extracted by 2 authors. Data were pooled using a random-effects method. Event rate of CTH use in patients with acute atraumatic AMS. The CTH event rates and positive CTH event rates were calculated with 95% CIs. Of 9338 studies identified, 26 qualified for the systematic review and 25 for the meta-analysis. The 25 studies in the meta-analysis included a total of 79 201 patients. The CTH event rate was 94% (proportion, 0.94; 95% CI, 0.76-1.00), and the positive CTH event rate was 11% (proportion, 0.11; 95% CI, 0.07-0.15). There was significant heterogeneity among the studies included (I2 > 50%, P < .001), for which a random-effects model was used. There was significant publication bias, as evident by an asymmetric funnel plot. There was no fluctuation of the results during the sensitivity analysis, which reassured the reliability of the data. In this meta-analysis, CTH use among patients with acute-onset atraumatic AMS was very high with a low yield. Large-scale studies are needed to guide clinical decision-making in such a situation.

Viscosupplementation for knee osteoarthritis: systematic review and meta-analysis

ObjectiveTo evaluate the effectiveness and safety of viscosupplementation for pain and function in patients with knee osteoarthritis.DesignSystematic review and meta-analysis of randomised trials.Data sourcesSearches were conducted of Medline, Embase, and...

Motion analysis and modulation of steel particle swarm in high-pressure tank for particle impact drilling

Particle Impact Drilling (PID) is a new technology to effectively improve the rate of penetration (ROP) for oil and gas drilling in hard and strongly abrasive formations. In this paper, numerical simulation method is used to analyse the motion characteristics and the modulation method of particle swarm in high-pressure tank for the particle injection system based on differential pressure ejection in PID. The numerical simulation results show that: when there is no modulation elements, the motion of particle swarm in the high-pressure tank follows an asymmetric funnel flow with pulsating state, which could be divided into vertical flow domain, fast flow domain, slow flow domain and stagnation domain. The unstable dynamic arching effect of the funnel flow, the viscous effect of the liquid bridge force and the collapsing effect of the particle swarm could probably lead to the blockage of the discharge port of the high-pressure tank. When the semiapex angles of the high-pressure tank decreases, the volume flow rate of particles increases and the stagnation domain becomes smaller, but it becomes easier to form arching and blockage. The modelling results indicate that the pulsation of the funnel flow is minimum when the semiapex angle is 45° without the mutilation element, which means the funnel flow of the particle swarm is relatively stable. By introducing a conical modulating element above the discharge port, the unstable funnel flow of the particle swarm could be transformed to an overall uniform flow. The modelling results indicate that the installation height of the modulation element has the greatest influence on the pulsation degree. The optimized parameters for the conical modulation element based on numerical modelling tests are 70° for the vertex angle, 35 mm for the length of the flank and 70 mm for the installation heigh.

Motion Analysis and Modulation of Steel Particle Swarm in High-Pressure Tank for Particle Impact Drilling

Particle Impact Drilling (PID) is a new technology to effectively improve the rate of penetration (ROP) for oil and gas drilling in hard and strongly abrasive formations. In this paper, numerical simulation method is used to analyze the motion characteristics and the modulation method of particle swarm in high-pressure tank for the particle injection system based on differential pressure ejection in PID. The numerical simulation results show that: when there is no modulation elements, the motion of particle swarm in the high-pressure tank follows an asymmetric funnel flow with pulsating state, which could be divided into vertical flow domain, fast flow domain, slow flow domain and stagnation domain. The unstable dynamic arching effect of the funnel flow, the viscous effect of the liquid bridge force and the collapsing effect of the particle swarm could probably lead to the blockage of the discharge port of the high-pressure tank. When the semiapex angles of the high-pressure tank decreases, the volume flow rate of particles increases and the stagnation domain becomes smaller, but it becomes easier to form arching and blockage. The modelling results indicate that the pulsation of the funnel flow is minimum when the semiapex angle is 45° without the mutilation element, which means the funnel flow of the particle swarm is relatively stable. By introducing a conical modulating element above the discharge port, the unstable funnel flow of the particle swarm could be transformed to an overall uniform flow. The modelling results indicate that the installation height of the modulation element has the greatest influence on the pulsation degree. The optimized parameters for the conical modulation element based on numerical modelling tests are 70° for the vertex angle, 35mm for the length of the flank and 70mm for the installation height.

Skyrmion ratchet in funnel geometries

Using a particle-based model, we simulate the behavior of a skyrmion under the influence of asymmetric funnel geometries and ac driving at zero temperature. We specifically investigate possibilities for controlling the skyrmion motion by harnessing a ratchet effect. Our results show that as the amplitude of a unidirectional ac drive is increased, the skyrmion can be set into motion along either the easy or hard direction of the funnel depending on the ac driving direction. When the ac drive is parallel to the funnel axis, the skyrmion flows in the easy direction and its average velocity is quantized. In contrast, when the ac drive is perpendicular to the funnel axis, a Magnus-induced ratchet effect occurs, and the skyrmion moves along the hard direction with a constant average velocity. For biharmonic ac driving of equal amplitude along both the parallel and perpendicular directions, we observe a reentrant pinning phase where the skyrmion ratchet vanishes. For asymmetric biharmonic ac drives, the skyrmion exhibits a combination of effects and can move in either the easy or hard direction depending on the configuration of the ac drives. These results indicate that it is possible to achieve controlled skyrmion motion using funnel geometries, and we discuss ways in which this could be harnessed to perform data transfer operations.

Bandpass filter based on asymmetric funnel shaped resonators with ultra wide upper stopband characteristics

A novel microstrip bandpass filter with wide passband, good skirt selectivity and very good passband reflection characteristics using asymmetric funnel shaped resonators is presented in this paper. IE3D simulation software is used for the design and analysis of the proposed filter and the electric field intensities at various frequencies of interest are plotted and verified the role of even and odd mode resonances in achieving wide passband. There are six modes, including three even and three odd modes for the developed filter. Novel equations are derived for finding out the location of transmission zeros and the role of resonators in achieving sharp selectivity are verified. The out of band performance of filter is very good with a suppression level greater than 20 dB upto 24.2 GHz. The centre frequency of the filter is 5.68 GHz with a fractional bandwidth of 97.57%. The fabrication process is carried out using MITS 11 Autolab fabrication machine with the low cost FR4 substrate and verified the performance improvement of the developed filter.

Effect of Moxibustion on Inflammatory Cytokines in Animals with Rheumatoid Arthritis: A Systematic Review and Meta-Analysis.

Background This study aims to systematically evaluate the effect of moxibustion on the level of inflammatory cytokines in animal models with rheumatoid arthritis (RA) and to provide evidence for the clinical application of moxibustion to the treatment of RA and related basic researches. Methods The databases employed in this study include PubMed, EMBASE, Web of Science, China National Knowledge Infrastructure (CNKI), Chinese Science and Technology Periodical Database (VIP), SinoMed, and Wanfang Data Information Site. The retrieval time was from the establishment of these databases to March 2020. The reviewers made use of the CAMARADES 10-item checklist to evaluate the quality of each included study. The inflammatory cytokines were considered as the outcome measure. The Revman 5.3 software was used to conduct meta-analysis on the outcome indicators of the studies included. Results A total of 648 articles were retrieved and 18 animal experiments were included in this study. The quality scores of the studies ranged from two to eight with a mean of 5.8. Compared with the effect of the control group, moxibustion reduced the expression of TNF-α (SMD 2.95, 95% CI: 1.99–3.92, P < 0.00001), IL-1β (SMD 4.10, 95% CI: 2.37–5.84, P < 0.00001), IFN-γ (MD 25, 95% CI: 16.17–33.82, P < 0.00001), IL-6 (MD 11.83, 95% CI: 6.22–17.44, P < 0.0001), and IL-17 (MD 99.3, 95% CI: 86.83–111.76, P < 0.00001). At the same time, the level of IL-2 (SMD 8.89, 95% CI: 0.93–16.86, P=0.03), IL-4 (MD 1.79, 95% CI: 0.26–3.32, P=0.02), and IL-10 (MD 5.93, 95% CI: 1.37–10.49, P=0.01) increased after moxibustion treatment. Asymmetric funnel plots indicated that there was publication bias. Conclusion The findings of the present review indicate that moxibustion can protect the synovium of joint in animal models with RA by upregulation of the level of anti-inflammatory cytokines and downregulation of the level of proinflammatory cytokines. Moxibustion has the potential to relieve inflammation of RA.

Effectiveness of Acupuncture in Treatment of Simple Obesity in Animal Models: A Systematic Review and Meta-Analysis.

Background Simple obesity has become a global risk to health of human beings. Acupuncture, as one of traditional Chinese medicine therapies, has been widely used in obesity treatment in recent years. However, the individual heterogeneity which makes acupuncture's efficiency unstable leads to some controversy. So more evidence-based results are necessary to judge the effectiveness of acupuncture in treatment of simple obesity. Compared with clinical trials, animal experiments are controllable, and the underlying mechanism is more likely to be explored. Last but not the least, more and more experimental studies on acupuncture for animal obesity have been published. Therefore, we conducted the systematic review and meta-analysis to evaluate the effectiveness of acupuncture in treating simple obesity in animal experiments. Methods Randomized Controlled Trials (RCTs) on acupuncture for simple obesity animal models were searched from six databases: PubMed, MEDLINE, CNKI, VIP, WanFang Date, and CMB from inception to February 2017 and updated on April 12, 2019. RevMan 5.3 software was used for meta-analysis. Treatment effects were summarized as relative risk (RR) and Standard mean difference (SMD) with 95% of confidence interval (CI). Results A total of 108 trials involving 5731 rats were included. Meta-analysis showed that acupuncture had better effect on reducing weight (SMD -2.60, 95%CI: -2.93 to -2.26, p<0.00001) and Lee's index (SMD -2.62, 95%CI:-3.18 to -2.06, p<0.00001) compared with control group. However, the methodological quality of included studies was generally poor. Details of blinding were not reported in most studies. In spite of high heterogeneity being observed on the merged data, sensitivity analysis using the leave-one-out approach, subgroup analysis based on different acupuncture techniques, and rat strains and meta-regression all failed to find the sources of heterogeneity. The asymmetric funnel plot suggested publication bias. Besides, adverse events were not reported in any reports. Conclusions Our review provided positive evidence of acupuncture for simple obesity. Unfortunately, none of the firm conclusions can be drawn due to methodological flaws, high heterogeneity, and publication bias. More high-quality trials are needed in future to get objective conclusions.

A comprehensive meta-analysis of money priming.

Research on money priming typically investigates whether exposure to money-related stimuli can affect people's thoughts, feelings, motivations, and behaviors (for a review, see Vohs, 2015). Our study answers the call for a comprehensive meta-analysis examining the available evidence on money priming (Vadillo, Hardwicke, & Shanks, 2016). By conducting a systematic search of published and unpublished literature on money priming, we sought to achieve three key goals. First, we aimed to assess the presence of biases in the available published literature (e.g., publication bias). Second, in the case of such biases, we sought to derive a more accurate estimate of the effect size after correcting for these biases. Third, we aimed to investigate whether design factors such as prime type and study setting moderated the money priming effects. Our overall meta-analysis included 246 suitable experiments and showed a significant overall effect size estimate (Hedges' g = .31, 95% CI [0.26, 0.36]). However, publication bias and related biases are likely given the asymmetric funnel plots, Egger's test and two other tests for publication bias. Moderator analyses offered insight into the variation of the money priming effect, suggesting for various types of study designs whether the effect was present, absent, or biased. We found the largest money priming effect in lab studies investigating a behavioral dependent measure using a priming technique in which participants actively handled money. Future research should use sufficiently powerful preregistered studies to replicate these findings. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Acupuncture for symptomatic gastroparesis.

Acupuncture for symptomatic gastroparesis.

Clogging and transport of driven particles in asymmetric funnel arrays

We numerically examine the flow and clogging of particles driven through asymmetric funnel arrays when the commensurability ratio of the number of particles per plaquette is varied. The particle–particle interactions are modeled with a soft repulsive potential that could represent vortex flow in type-II superconductors or driven charged colloids. The velocity-force curves for driving in the easy flow direction of the funnels exhibit a single depinning threshold; however, for driving in the hard flow direction, we find that there can be both negative mobility where the velocity decreases with increasing driving force as well as a reentrant pinning effect in which the particles flow at low drives but become pinned at intermediate drives. This reentrant pinning is associated with a transition from smooth 1D flow at low drives to a clogged state at higher drives that occurs when the particles cluster in a small number of plaquettes and block the flow. When the drive is further increased, particle rearrangements occur that cause the clog to break apart. We map out the regimes in which the pinned, flowing, and clogged states appear as a function of plaquette filling and drive. The clogged states remain robust at finite temperatures but develop intermittent bursts of flow in which a clog temporarily breaks apart but quickly reforms.

Identifying Conformational-Selection and Induced-Fit Aspects in the Binding-Induced Folding of PMI from Markov State Modeling of Atomistic Simulations

Unstructured proteins and peptides typically fold during binding to ligand proteins. A challenging problem is to identify the mechanism and kinetics of these binding-induced folding processes in experiments and atomistic simulations. In this Article, we present a detailed picture for the folding of the inhibitor peptide PMI into a helix during binding to the oncoprotein fragment 25-109Mdm2 obtained from atomistic, explicit-water simulations and Markov state modeling. We find that binding-induced folding of PMI is highly parallel and can occur along a multitude of pathways. Some pathways are induced-fit-like with binding occurring prior to PMI helix formation, while other pathways are conformational-selection-like with binding after helix formation. On the majority of pathways, however, binding is intricately coupled to folding, without clear temporal ordering. A central feature of these pathways is PMI motion on the Mdm2 surface, along the binding groove of Mdm2 or over the rim of this groove. The native binding groove of Mdm2 thus appears as an asymmetric funnel for PMI binding. Overall, binding-induced folding of PMI does not fit into the classical picture of induced fit or conformational selection that implies a clear temporal ordering of binding and folding events. We argue that this holds in general for binding-induced folding processes because binding and folding events in these processes likely occur on similar time scales and do exhibit the time-scale separation required for temporal ordering.

PROTOCOL: Electronic mentoring to promote positive youth outcomes for young people under 25: a systematic review.

PROTOCOL: Electronic mentoring to promote positive youth outcomes for young people under 25: a systematic review.

Replica Exchange Wang—Landau Simulation of Lattice Protein Folding Funnels

The resolution of Levinthal’s paradox concerning the ability of proteins to fold rapidly postulates the existence of a rough “folding funnel” in free energy space that guides the protein to its lowest free energy, native state. To study the folding of the protein ribonuclease A we have mapped it onto a 124 monomer, coarse-grained HP lattice model and onto an H0P model that also includes “neutral” 0-mers in addition to the hydrophobic H-mers and polar P-mers. Using Replica Exchange Wang-Landau sampling, we determined the density of states, g(E), which we then used to calculate the free energy of the protein vs end-to-end distance as a function of temperature. At low temperature the HP model shows a rather shallow and at free energy minimum, while the H0P model maintains a rough free energy funnel. Unlike the common, schematic figures, we find an asymmetric folding funnel that also changes shape substantially as the temperature decreases. Even the location of the free energy minimum shifts as the temperature decreases.

Effectiveness of collective treatments in the prevention and treatment of bovine digital dermatitis lesions: A systematic review.

The collective treatment (CT) of an affected herd is commonly advised to control bovine digital dermatitis (DD). Several CT are commercialized, frequently without major evidence supporting their effectiveness. The objective of this systematic review was to evaluate the published evidence that supports CT in the treatment and prevention of DD lesions in dairy herds. Across the evidence, the main limitations in the studies design were identified and the possible sources of inconsistency were investigated. An extensive literature search of publications through electronic databases and gray literature was conducted between July 2015 and January 2016. Studies that did not include an untreated or placebo control group were excluded from the review. The literature search and screening process identified 13 publications with 24 treatment trial comparisons and 18 prevention trial comparisons. The published evidence included studies mostly considered to have a low or unclear risk of bias. Descriptive analyses were performed according to the prevention and treatment outcomes, and case and success definitions were identified for each study and summarized in odds ratios (OR). Pairwise meta-analyses were conducted according to the prevention and treatment outcomes, comparing directly the intervention used in each study, and ignoring any other differences in the intervention characteristics. The results of the meta-analyses indicated a low degree of heterogeneity across the evidence for the prevention outcome [I2 = 0%, 95% CI: 0 to 37.2%, 95% prediction interval (PI): 0.72 to 1.74)] and a moderate degree for the treatment outcome (I2 = 25.3%, 95% CI: 0 to 63%, 95% PI: 0.39 to 3.73). Similarly, appraisal of the graphical L'Abbé plot suggested a considerable degree of heterogeneity across the evidence for the treatment outcome. For both outcomes, the frequent small sample sizes of the trials indicate imprecision across the included studies. Additionally, for the treatment and prevention outcomes, an asymmetric funnel plot suggested possible publication bias. The overall quality of the evidence, for both outcomes (prevention and treatment), was therefore considered to be low, indicating that the true effect of CT may be substantially different from that estimated across the included studies. Consequently, this review and meta-analysis does not support an association between the CT considered in the review and a beneficial effect in the prevention and treatment of DD lesions. The effectiveness of CT therefore remains uncertain, and the epidemiological circumstances in which it can be useful must be investigated. These findings highlight the importance of developing high quality, controlled trials to evaluate the effectiveness of CT for DD control.