Pedicle screws (PSs) are routinely used for stabilization to enhance fusion in a variety of spinal diseases. Although the accuracy of different PS placement methods has been previously reported, most ...of these studies have been limited to 1 or 2 techniques. The purpose was to determine the current accuracy of PS placement among 4 modalities of PS insertion (freehand FH, fluoroscopy-assisted FA, computed tomography navigation–guided CTNav, and robot-assisted RA) and analyze variables associated with screw misplacement.
A systematic review was performed of peer-reviewed articles reporting PS accuracy of 1 technique from January 1990 to June 2018. Accuracy of PS placement, PS insertion technique, and pedicle breach (PB) data were collected. A meta-analysis was performed to estimate the overall pooled (OP) rates of PS accuracy as a primary outcome, stratified by screw insertion techniques. Potential determinants were analyzed via meta-regression analyses.
Seventy-eight studies with 7858 patients, 51,161 PSs, and 3614 cortical PBs were included. CTNav showed the highest PS placement accuracy compared with other techniques: OP accuracy rates were 95.5%, 93.1%, 91.5%, and 90.5%, via CTNav, FH, FA, and RA techniques, respectively. RA and CTNav were associated with the highest PS accuracy in the thoracic spine, compared with FH.
The OP data show that CTNav has the highest PS accuracy rates. Thoracic PSs were associated with lower accuracy rates; however, RA showed fewer breaches in the thoracic spine compared with FH and FA. Given the heterogeneity among studies, further standardized and comparative investigations are required to confirm our findings.
Alternative route to a 2D superconductor
Single layers of transition metal dichalcogenides exhibit exotic properties, including superconductivity. The usual route to obtaining such samples is to ...exfoliate a three-dimensional (3D) crystal. Devarakonda
et al.
instead grew a superlattice comprising alternating layers of the transition metal dichalcogenide hexagonal NbS
2
and the material Ba
3
NbS
5
(see the Perspective by Schoop). The inert Ba
3
NbS
5
layers serve to dissociate the superconducting NbS
2
layers from one another, resulting in 2D superconductivity with high carrier mobility. The combination of high mobility and reduced dimensionality may give rise to exotic quantum phases.
Science
, this issue p.
231
see also p.
170
A superlattice of alternating layers of
H
-NbS
2
and Ba
3
NbS
5
exhibits 2D superconductivity and high carrier mobility.
Advances in low-dimensional superconductivity are often realized through improvements in material quality. Apart from a small group of organic materials, there is a near absence of clean-limit two-dimensional (2D) superconductors, which presents an impediment to the pursuit of numerous long-standing predictions for exotic superconductivity with fragile pairing symmetries. We developed a bulk superlattice consisting of the transition metal dichalcogenide (TMD) superconductor 2
H
-niobium disulfide (2
H
-NbS
2
) and a commensurate block layer that yields enhanced two-dimensionality, high electronic quality, and clean-limit inorganic 2D superconductivity. The structure of this material may naturally be extended to generate a distinct family of 2D superconductors, topological insulators, and excitonic systems based on TMDs with improved material properties.
Breast cancer has replaced lung cancer as the most common malignant tumor in the world. Precise surgical, internal medicine, targeted, radiotherapy, immunotherapy and other treatment methods will ...improve the survival and quality of life of patients. Accurate pathological diagnosis is the prerequisite and key to achieve clinical accurate treatment. This article makes a review of the relevant content of different submitted specimens and precise pathological diagnosis of breast cancer.
Retrospective comparative study.
To compare clinical and radiographic outcomes between the S2-alar-iliac (S2AI) and the iliac screw (IS) techniques in the adult population and clarify the clinical ...strength of S2AI screws.
S2AI screws have been described as an alternative method for lumbosacropelvic fixation in place of ISs. The S2AI technique has several advantages with lower prominence, increased ability to directly connect to proximal instrumentation, less extensive dissection of tissue, and enhanced biomechanical strength over the IS technique. However, the clinical significance of these advantages remains unclear.
A single-center retrospective review of patients who underwent lumbosacropelvic fixation yielded 25 IS group patients and 65 S2AI group patients. Baseline demographic information, postoperative complications, pain and functional outcomes, and screw-related outcomes were collected.
The S2AI group had lower rates of reoperation (8.8% vs. 48.0%, P < 0.001), surgical site infection (SSI) (1.5% vs. 44.0%, P < 0.001), wound dehiscence (1.5% vs. 36.0%, P < 0.001), and symptomatic screw prominence (0.0% vs. 12.0%, P = 0.02) than the IS group, whereas rates of L5-S1 pseudarthrosis, proximal junctional failure, and sacroiliac joint pain were similar in both groups. Statistically significant pain relief and functional recovery were achieved in both groups without any significant intergroup differences. On multivariate analyses, age odds ratio (OR) = 0.91, P = 0.004 and S2AI instrumentation (OR = 0.08, P < 0.001) were protective of reoperation, whereas diabetes mellitus (OR = 10.9, P = 0.03) and preoperative diagnosis of tumor (OR = 12.3, P = 0.04) were associated with SSI, and S2AI instrumentation (OR = 0.09, P < 0.001) was protective of SSI.
The use of the S2AI technique over the IS technique was an independent predictor of preventing reoperation and SSI, while achieving similar clinical and functional outcomes.
4.
Detection of low viral load samples has long been a challenge for African swine fever (ASF) prevention and control. This study aimed to compare the detection efficacy of droplet digital PCR(ddPCR) ...and quantitative PCR(qPCR) for African swine fever virus (ASFV) at different viral loads, with a focus on assessing the accuracy of ddPCR in detecting low viral load samples. The results revealed that ddPCR had a detection limit of 1.97 (95% CI 1.48 – 4.12) copies/reaction and was 18.99 times more sensitive than qPCR (detection limit: 37.42, 95% CI 29.56 – 69.87 copies/reaction). In the quantification of high, medium, and low viral load samples, ddPCR showed superior stability with lower intra- (2.06% – 7.58%) and inter-assay (3.83% – 7.50%) coefficients of variation than those of qPCR (intra-assay: 8.08%–29.86%; inter-assay: 9.27%–34.58%). Bland-Altman analysis indicated acceptable consistency between ddPCR and qPCR for high and medium viral load samples; however, discrepancies were observed for low viral load samples, where two samples (2/24, 8.33%) exhibited deviations beyond the acceptable range (−46.18 copies/reaction). Moreover, ddPCR demonstrated better performance in detecting ASFV in clinical samples from asymptomatic pigs and environmental samples, with qPCR showing false negative rates of 7.69% (2/26) and 27.27% (12/44), respectively. McNemar analysis revealed significant differences between the two methods (P = 0.000) for samples with a viral load <100 copies/reaction. The results of this study demonstrate that ddPCR has better detection limits and adaptability than qPCR, allowing for a more accurate detection of ASFV in early-stage infections and low-concentration environmental samples. These findings highlight the potential of ddPCR in the prevention and control of ASF.
0.5 mm thick AA7075-T6 ultra-thin sheets were joined successfully by high rotational speed friction stir welding using a pinless tool. Friction stir welding was performed under a high rotational ...speed of 6000 rpm, and the travel speed ranged from 300 mm/min to 1200 mm/min. Zero thickness reduction and delamination phenomenon were observed in the nugget zone when the travel speed was 1200 mm/min. In this condition, the dynamic recrystallization occurred in the lower part of the nugget zone is incomplete. The mechanical properties gradually improved with the increasing in the travel speed. All the tensile specimens fractured along the boundary between the thermo-mechanically affected zone and the nugget zone, and the morphology showed a shear fracture mode. The maximum tensile strength of 482 MPa (equivalent to ∼90% of base metal) was obtained at the travel speed of 1200 mm/min, which presented a ductile fracture mode and a large amount of η phase (MgZn2) precipitates and thick tear ridges were detected on the fracture surfaces.
Eleven grape cultivars were analysed to explore the variety differences of fresh grape phenolic profiles.The results showed that free phenolics were predominant in grape skins and pulps,and showed ...the higher antioxidant activities than bound.In 11 cultivars,Muscat Kyoho extracts had the highest total phenolic content in skins (10.525 mg GAE g-1 FW) and pulps (1.134 mg GAE g-1 FW),and exhibited the highest DPPH radical scavening capacity (EC50=11.7 μg mL-1) and oxygen radical absorbance capacity (ORAC) value (190.57 μmol TE g-1 FW) of free phenolic in skin.In addition,the most abundant phenolics in grape skins were found to be flavonoids such as kaempferol in Kyoho skin (541.2 μg g-1 FW),rutin,catechin and epicatechin in Muscat Kyoho skin (262.3,86.3 and 70.0 μg g-1 FW,respectively).Furthermore,the principal component analysis showed a strong difference of phenolic profiles with the cultivars,existing forms and distributions.Pearson correlation coefficient analysis showed a significant linear correlation between total phenolic content and antioxidant activity (P＜0.05).Therefore,both skins and pulps were rich sources of bioactive phenolic compounds,and Muscat Kyoho was the ideal source among all samples.
Abstract Mild cognitive impairment (MCI) has often been studied in its association with dementia, yet higher rates of reversion to normal cognition than progression to dementia suggest that MCI does ...not necessarily lead to dementia.
Compared to the numerous studies on MCI progression, relatively few have examined reversion.
This paper highlights the current literature on characteristics and predictive factors of MCI reversion, along with an overview of studies on MCI patients who remain diagnostically stable (i.e., MCI stability).
Of the available studies, predictors of reversion have been noted in areas of cognitive/global functioning, demographic/genetic/biomarker data, and personality/lifestyle factors.
However, there is a need for increased study of MCI reversion, considering that patients in this group can fluctuate between different trajectories of MCI (e.g., normal cognition back to MCI or even progression to dementia) within a given follow-up time period.
Further examination of reversion via a longitudinal, multifactorial approach would better inform clinicians regarding the likelihood of reversion amongst MCI patients and subsequently modify treatment methods accordingly.
Furthermore, researchers would have greater power in detecting treatment effects in their clinical intervention studies of early dementia by improving selection criteria to exclude MCI participants who are more likely to revert and remain cognitively normal than progress to a dementia.
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