Unveiling the Composition-Dependent Catalytic Mechanism of Pt-Ni Alloys for Oxygen Reduction: A First-Principles Study.

Unveiling the composition-dependent catalytic mechanism of Pt-based alloy cathodes for the oxygen reduction reaction (ORR) helps improve the proton exchange membrane fuel cells. Using density functional theory calculations, this study investigates the ORR catalytic performance of the Pt-Ni system with various compositions (1.00, ∼0.99, 0.75, 0.50, 0.25, ∼0.01, and 0.00). The ordered solid solution PtNi3(111) system shows activity comparable to Pt(111) and is cost-effective. The Ni1/Pt(111) system, featuring a single Ni atom on the Pt(111) surface as a surface single-atom alloy (SSAA), demonstrates the highest activity with an overpotential of only 0.28, which could be further reduced to 0.21 V by decreasing the surface Ni concentration to 1/16 monolayer coverage. The predicted high activity of Ni1/Pt(111) is confirmed when considering factors such as the implicit solution environment, constant potential conditions, and protonation capability. Moreover, surface-adsorbed oxygen species driven by reaction conditions stabilize these single Ni atoms of Ni1/Pt(111) by preventing segregation and dissolution processes, thereby exhibiting a dual functionality. This study reveals the composition dependence of Pt-based alloys and highlights the stability mechanisms of SSAA catalysts during the ORR.

Strong and Fatigue-Resistant Carbon Nanotube Composites Enabled by Amorphous/Crystalline Heterophase Shell.

Lightweight materials with high strength and long cyclic lifespan are greatly demanded in practical applications, yet these properties are usually mutually exclusive. Here, we present a strong, lightweight, highly deformation-tolerant, and fatigue-resistant carbon nanotube (CNT) composite enabled by an amorphous/crystalline heterophase carbon shell. In particular, we obtain nanocrystallites with CNT-induced crystalline orientation uniformly embedded within an amorphous matrix by controlled thermal annealing. The heterophase carbon shell effectively alleviates the stress concentration and inhibits crack propagation, which renders our composite superior mechanical properties and high fatigue resistance (106 compression cycles at 20% strain with high stress of 144 kPa, or 5 × 105 cycles at 50% strain with stress up to 260 kPa). This study provides a deep understanding of amorphous-crystalline phase transition and insight into utilizing phase engineering to design and develop other high-performance functional materials such as structural materials and catalysis.

Prognostic implications of residual mild coarctation gradient after interventional repair.

There is limited data on the prognostic implications of residual mild coarctation (RMC) in patients with repaired native coarctation of the aorta (CoA). To explore the association of RMC with mid-term comorbidities in post-interventional patients, and the predictive value of the residual pressure gradient. The authors retrospectively analyzed 79 native CoA patients who received successful intervention at our hospital between October 2010 and June 2023. The outcomes of the study were late arterial hypertension (either raised blood pressure or commencement of hypotensive medications) only in normotensive patients at early follow-up and the composite mid-term comorbidities including new-onset aortic injury, re-stenosis, and re-intervention. At a median follow-up of 60 months, late hypertension and mid-term comorbidities occurred in 16 (28.1%) and nine (11.4%) patients, respectively. Multivariate Cox proportional hazard regression analysis identified invasive peak systolic CoA pressure gradient (PSPG) as the best independent predictor of both outcomes. The maximally selected rank statistics indicated 10 mm Hg as the best PSPG cut-off value for predicting late hypertension. Compared to patients with PSPG < 11 mm Hg, the cumulative event rates of both outcomes were higher in those with PSPG ≥ 11 mm Hg (log-rank test, p < .001 for both endpoints). PSPG ≥ 11 mm Hg was proved to be the independent predictor of late hypertension with a significantly increased risk. In patients with non-surgical CoA repair, the post-interventional RMC and PSPG ≥11 mm Hg are important predictors of clinical comorbidities at mid-term follow-up.

Ultra-Large Stress and Strain Polymer Nanocomposite Actuators Incorporating a Mutually-Interpenetrated, Collective-Deformation Carbon Nanotube Network.

Stimulus-responsive polymer-based actuators are extensively studied, with the challenging goal of achieving comprehensive performance metrics that include large output stress and strain, fast response, and versatile actuation modes. The design and fabrication of nanocomposites offer a promising route to integrate the advantages of both polymers and nanoscale fillers, thus ensuring superior performance. Here, it is started from a three-dimensional (3D) porous sponge to fabricate a mutually interpenetrated nanocomposite, in which the embedded carbon nanotube (CNT) network undergoes collective deformation with the shape memory polymer (SMP) matrix during large-degree stretching and releasing, increases junction density with polymer chains and enhances molecular orientation. These features result in substantial improvement of the overall mechanical properties and during thermally actuated contraction, the bulk SMP/CNT composites exhibit output stresses up to 19.5 ± 0.97 MPa and strains up to 69%, accompanied by a rapid response and high energy density, exceeding the majority of recent reports. Furthermore, electrical actuation is also demonstrated via uniform Joule heating across the self-percolated CNT network. Applications such as low-temperature thermal actuated vascular stent and wound dressing are explored. These findings lay out a universal blueprint for developing robust and highly deformable SMP/CNT nanocomposite actuators with broad potential applications.

Self-Assembly Intermetallic PtCu3 Core with High-Index Faceted Pt Shell for High-Efficiency Oxygen Reduction.

Rational design of well-defined active sites is crucial for promoting sluggish oxygen reduction reactions. Herein, leveraging the surfactant-oriented and solvent-ligand effects, we develop a facile self-assembly strategy to construct a core-shell catalyst comprising a high-index Pt shell encapsulating a PtCu3 intermetallic core with efficient oxygen-reduction performance. Without undergoing a high-temperature route, the ordered PtCu3 is directly fabricated through the accelerated reduction of Cu2+, followed by the deposition of the remaining Pt precursor onto its surface, forming high-index steps oriented by the steric hindrance of surfactant. This approach results in a high half-wave potential of 0.911 V versus reversible hydrogen electrode, with negligible deactivation even after 15000-cycle operation. Operando spectroscopies identify that this core-shell catalyst facilitates the conversion of oxygen-involving intermediates and ensures antidissolution ability. Theoretical investigations rationalize that this improvement is attributed to reinforced electronic interactions around high-index Pt, stabilizing the binding strength of rate-determining OHads species.

Estimation of Protein and Amino Acid Requirements in Layer Chicks Depending on Dynamic Model.

Four trials were conducted to establish a protein and amino acid requirement model for layer chicks over 0-6 weeks by using the analytical factorization method. In trial 1, a total of 90 one-day-old Jing Tint 6 chicks with similar body weight were selected to determine the growth curve, carcass and feather protein deposition, and amino acid patterns of carcass and feather proteins. In trials 2 and 3, 24 seven-day-old and 24 thirty-five-day-old Jing Tint 6 chicks were selected to determine the protein maintenance requirements, amino acid pattern, and net protein utilization rate. In trial 4, 24 ten-day-old and 24 thirty-eight-day-old Jing Tint 6 chicks were selected to determine the standard terminal ileal digestibility of amino acids. The chicks were fed either a corn-soybean basal diet, a low nitrogen diet, or a nitrogen-free diet throughout the different trials. The Gompertz equation showed that there is a functional relationship between body weight and age, described as BWt(g) = 2669.317 × exp(-4.337 × exp(-0.019t)). Integration of the test results gave a comprehensive dynamic model equation that could accurately calculate the weekly protein and amino acid requirements of the layer chicks. By applying the model, it was found that the protein requirements for Jing Tint 6 chicks during the 6-week period were 21.15, 20.54, 18.26, 18.77, 17.79, and 16.51, respectively. The model-predicted amino acid requirements for Jing Tint 6 chicks during the 6-week period were as follows: Aspartic acid (0.992-1.284), Threonine (0.601-0.750), Serine (0.984-1.542), Glutamic acid (1.661-1.925), Glycine (0.992-1.227), Alanine (0.909-0.961), Valine (0.773-1.121), Cystine (0.843-1.347), Methionine (0.210-0.267), Isoleucine (0.590-0.715), Leucine (0.977-1.208), Tyrosine (0.362-0.504), Phenylalanine (0.584-0.786), Histidine (0.169-0.250), Lysine (0.3999-0.500), Arginine (0.824-1.147), Proline (1.114-1.684), and Tryptophan (0.063-0.098). In conclusion, this study constructed a dynamic model for the protein and amino acid requirements of Jing Tint 6 chicks during the brooding period, providing an important insight to improve precise feeding for layer chicks through this dynamic model calculation.

Patient preferences and willingness to pay for central venous access devices in breast cancer: A multicenter discrete choice experiment.

BACKGROUND: Despite being a significant management decision in clinical or nursing practice, there is limited understanding of the preferences regarding risks, benefits, costs, and other attributes of patients with breast cancer when selecting peripherally inserted central catheters or totally implanted ports. The objective of this study is to investigate the preferences of patients with breast cancer who require chemotherapy when selecting an optimal central venous access device. METHODS: Data on patients' preferences for central venous access devices were collected using a face-to-face discrete choice experiment from the oncology departments of three public hospitals in China representing the eastern (Zhejiang province), central (Henan province), and western (Sichuan province) regions. The study used six attributes to describe the preferences of breast cancer patients for central venous access devices, including out-of-pocket cost, limitations in activities of daily living, catheter maintenance frequency, risk of catheter-related thrombosis, risk of catheter-related infection, and size of incision. Data were analyzed using a conditional logit model and mixed logit model. The marginal willingness to pay (mWTP) was calculated by assessing the ratio of the preference for other attributes to the preference for out-of-pocket cost. RESULTS: A total of 573 respondents completed the survey. The discrete choice experiment results showed that respondents strongly preferred a central venous access device with a catheter maintenance frequency of one time a month (vs four times a month, ß = 1.188, p < 0.001), the lower risk of catheter-related thrombosis (2 % vs 10 %, ß = 1.068; p < 0.001) and lower risk of catheter-related infection (2 % vs 8 % risk: ß = 0.824; p < 0.001). Respondents were willing to pay CNY ¥11,968.1 (US$1776.5) for a central venous access device with a catheter maintenance frequency of one time a month rather than four times a month, ¥10,753.6 (US$1596.2) for a central venous access device with 2 % thrombosis risk over one with 10 %, and ¥8302.0 (US$1232.3) for a central venous access device with 2 % infection risk over one with 8 %. Respondents with longer travel time to the hospital, younger than 50 years old, and with urban employee basic medical insurance were willing to pay more for an improvement in the attributes. CONCLUSIONS: These findings suggest that patients with breast cancer were mainly concerned with the out-of-pocket cost, catheter maintenance frequency, risk of catheter-related thrombosis and risk of catheter-related infection when choosing a central venous access device for the delivery of chemotherapy. In clinical or nursing practice, when making central venous access device recommendation for young patients and those who live far from hospitals, totally implanted ports may be a preferable choice.

Hemodynamics, anatomy, and outcomes of quadricuspid aortic valves: Multimodality imaging assessment.

BACKGROUND: Quadricuspid aortic valve (QAV) is a rare congenital heart disease with a limited body of literature. This retrospective cohort study investigates QAV morphology, function, and clinical outcomes. METHODS: Echocardiography was used to assess valvular function. Morphological characteristics such as phenotypes, raphe, regurgitant orifice area (ROA), and aortic dilation (diameter >40 â€‹mm) were assessed by cardiac CT. Patients were followed up for the combined event of all-cause death and aortic valve replacement (AVR). RESULTS: Ninety QAV patients (screened from 322385 CT scans) were included (mean age 55.2 â€‹± â€‹13.6 years, 61.1 â€‹% male). Isolated significant aortic regurgitation (AR) was present in 75.6 â€‹% of patients. The cohort was dominated by type I (four equal leaflets, 37.8 â€‹%) and type II (3 larger and 1 smaller leaflets, 42.2 â€‹%) QAV. Fused raphe was present in 26.7 â€‹% of patients. ROACT was correlated with AR severity and aortic dilation (41.1 â€‹%, n â€‹= â€‹37). Among patients without AVR at baseline (n â€‹= â€‹60), one died and 17 underwent AVR during a median follow-up of 35.0 months (IQR:17.3-62.8). ROACT was associated with an increasing risk of combined event (as a categorical variable with a cut-off of 21.4 â€‹mm2, HR â€‹= â€‹4.25, 95%CI 1.49-12.17, p â€‹= â€‹0.007; as a continuous variable (per mm2 increment), HR â€‹= â€‹1.04, 95%CI 1.01-1.07, p â€‹= â€‹0.003). Additionally, ROACT had incremental prognostic value when added to the AR severity model (area under the receiver-operating characteristic curve increased from 86.8 to 88.4, p â€‹= â€‹0.004). CONCLUSION: QAV is characterized by variable anatomy, progressive AR, concomitant cusp fusion and aortic enlargement. ROACT may be a potential ancillary prognostic marker in patients with QAV.

Circulating tumor DNA analysis predicts recurrence and avoids unnecessary adjuvant chemotherapy in I-IV colorectal cancer.

Background: Circulating tumor DNA (ctDNA) has emerged as a biomarker that can define the risk of recurrence after curative-intent surgery for patients with colorectal cancer (CRC). However, beyond the predictive power of postoperative ctDNA detection, the efficacy and potential limitations of ctDNA detection urgently need to be fully elucidated in a large cohort of CRC. Objectives: To define potentially cured CRC patients through ctDNA monitoring following surgery. Design: A prospective, multicenter, observational study. Methods: We enrolled 309 patients with stages I-IV CRC who underwent definitive surgery. Tumor tissues were sequenced by a custom-designed next-generation sequencing panel to identify somatic mutations. Plasma was analyzed using a ctDNA-based molecular residual disease (MRD) assay which integrated tumor-genotype-informed and tumor-genotype-naïve ctDNA analysis. The turnaround time of the assay was 10-14 days. Results: Postoperative ctDNA was detected in 5.4%, 13.8%, 15%, and 30% of patients with stage I, II, III, and IV disease, respectively, and in 17.5% of all longitudinal samples. Patients with positive postsurgery MRD had a higher recurrence rate than those with negative postsurgery MRD [hazard ratio (HR), 13.17; p < 0.0001], producing a sensitivity of 64.6%, a specificity of 94.8%, a positive predictive value (PPV) of 75.6%, and a negative predictive value (NPV) of 91.5%. Furthermore, patients with positive longitudinal MRD also had a significantly higher recurrence rate (HR, 14.44; p < 0.0001), with increased sensitivity (75.0%), specificity (94.9%), PPV (79.6%), and NPV (93.4%). Subgroup analyses revealed that adjuvant therapy did not confer superior survival for patients with undetectable or detectable MRD. In addition, MRD detection was less effective in identifying lung-only and peritoneal metastases. Conclusion: Postoperative ctDNA status is a strong predictor of recurrence independent of stage and microsatellite instability status. Longitudinal undetectable MRD could be used to define the potentially cured population in CRC patients undergoing curative-intent surgery.

Shape-changing electrode array for minimally invasive large-scale intracranial brain activity mapping.

Large-scale brain activity mapping is important for understanding the neural basis of behaviour. Electrocorticograms (ECoGs) have high spatiotemporal resolution, bandwidth, and signal quality. However, the invasiveness and surgical risks of electrode array implantation limit its application scope. We developed an ultrathin, flexible shape-changing electrode array (SCEA) for large-scale ECoG mapping with minimal invasiveness. SCEAs were inserted into cortical surfaces in compressed states through small openings in the skull or dura and fully expanded to cover large cortical areas. MRI and histological studies on rats proved the minimal invasiveness of the implantation process and the high chronic biocompatibility of the SCEAs. High-quality micro-ECoG activities mapped with SCEAs from male rodent brains during seizures and canine brains during the emergence period revealed the spatiotemporal organization of different brain states with resolution and bandwidth that cannot be achieved using existing noninvasive techniques. The biocompatibility and ability to map large-scale physiological and pathological cortical activities with high spatiotemporal resolution, bandwidth, and signal quality in a minimally invasive manner offer SCEAs as a superior tool for applications ranging from fundamental brain research to brain-machine interfaces.

An integrated mycotoxin-mitigating agent can effectively mitigate the combined toxicity of AFB1, DON and OTA on the production performance, liver and oviduct health in broiler breeder hens.

This study was to evaluate the efficacy of an integrated mycotoxin-mitigating agent in reducing the adverse effects of co-occurring dietary aflatoxin B1 deoxynivalenol and ochratoxin A on broiler breeder hens. 360 30-week-old Hubbard Efficiency Plus broiler breeder hens were allocated into four groups and received a basal diet (BD; Control), BD added 0.15 mg/kg aflatoxin B1+1.5 mg/kg deoxynivalenol+0.12 mg/kg ochratoxin A (Toxins), BD plus Toxins with 0.1% TOXO-XL (Toxins + XL1), and BD plus Toxins with 0.2% TOXO-XL (Toxins + XL2), respectively, for 8 weeks, and then received the same BD for another 4 weeks. Compared with control, mycotoxins decreased total egg weigh, egg laying rate, settable eggs rate, hatch of total eggs rate, egg quality, but increased feed/egg ratio and mortality rate, and impaired the liver and oviduct health during weeks 1-8 and(or) 9-12. It also increased PC and MDA concentrations, TUNEL-positive cells and IL-1ß and IL-6 expression, and decreased T-AOC, GPX and CAT activities in liver and/or oviduct. Notably, most of these negative changes were mitigated by both dosages of TOXO-XL. Generally, 0.2% TOXO-XL displayed better mitigation effects than 0.1% TOXO-XL. Conclusively, these findings revealed that TOXO-XL could mitigate the combined mycotoxins-induced toxicity on the performance, liver and oviduct health, through the regulation of redox, immunity, and apoptosis in broiler breeder hens.

Orthogonal-Channel, Low-Tortuosity Carbon Nanotube Platforms for High-Performance Li-O2 Batteries.

Aerogels and foams are promising electrode materials owing to their lightweight, high porosity, and large surface area for creating abundant active/catalytic sites. Tailoring their porous structure is essential toward maximum electrode performance yet remains challenging in the field. Here, by modifying a pristine carbon nanotube (CNT) sponge with random internal distribution, we present a CNT platform consisting of regular, orthogonally intercrossed through-channels centered at a suitable lateral size (around 5 µm), with low tortuosity and enhanced electrochemical kinetics under predefined compression. Our CNT platforms, grafted by bifunctional transitional metal hydroxide catalyst, overcome considerable challenges of both long cycle life and high rates simultaneously, serving as Li-O2 cathodes and achieving lifetime of 500 cycles at 0.5 mA cm-2 (275 cycles even at 1 mA cm-2) and also displaying high areal capacity (27 mA h cm-2), which are superior to most of the recently reported porous electrodes based on various materials. The mechanism involving fast triple-phase transport and reversible discharge product deposition, enabled by catalyst-loaded orthogonal channels, has been disclosed. Such structure-tailored robust CNT platforms could find many applications in electrochemical catalysis and energy storage systems.

Effects of conjugates of ε-polylysine-dextran created through Maillard reaction on quality and storage stability of the chicken gel.

The present study mainly focused on the effects of the conjugates of PL-dextran produced through the Maillard reaction on the quality and storage stability of chicken gel for 5 days at 4 ℃. According to the results of the texture profile, water retention capacity (WRC), low-field nuclear magnetic resonance (LF NMR), aerobic plate count (APC), and total volatile basic nitrogen (TVBN), ε-polylysine (PL) could improve chicken gel storage stability while decreasing the quality of protein gels (p < 0.05). Additionally, adding dextran with high or low molecular weight could significantly increase the quality of gel during storage (p < 0.05), whereas decreased storage stability could be obtained (p < 0.05). In general, conjugates formed by PL and dextran with high molecular weight were beneficial for quality maintenance. In comparison, the polymers produced from the low molecular weight of dextran could modify the storage stability of gels. Adding conjugates of dextran and PL benefited the structure formation of protein gel, while PL would retain part of antibacterial activity when crosslinked with dextran. Therefore, it could be concluded that the quality improvement effect of PL-dextran addition on gel quality was greater than its antibacterial effect, which would impact the formulation design of novel emulsion-type meat products.

Understanding Synergistic Catalysis on Cu-Se Dual Atom Sites via Operando X-ray Absorption Spectroscopy in Oxygen Reduction Reaction.

The construction and understanding of synergy in well-defined dual-atom active sites is an available avenue to promote multistep tandem catalytic reactions. Herein, we construct a dual-hetero-atom catalyst that comprises adjacent Cu-N4 and Se-C3 active sites for efficient oxygen reduction reaction (ORR) activity. Operando X-ray absorption spectroscopy coupled with theoretical calculations provide in-depth insights into this dual-atom synergy mechanism for ORR under realistic device operation conditions. The heteroatom Se modulator can efficiently polarize the charge distribution around symmetrical Cu-N4 moieties, and serve as synergistic site to facilitate the second oxygen reduction step simultaneously, in which the key OOH*-(Cu1 -N4 ) transforms to O*-(Se1 -C2 ) intermediate on the dual-atom sites. Therefore, this designed catalyst achieves satisfied alkaline ORR activity with a half-wave potential of 0.905 V vs. RHE and a maximum power density of 206.5 mW cm-2 in Zn-air battery.

A functional analysis of the effects of the molecular weight of dextran on ε-polylysine-dextran conjugate created through the maillard reaction.

The present study mainly examines the effects of molecular weight of dextran on the reaction rate and functional characteristics between ε-polylysine (PL) and dextran. The reaction kinetics, grafting degree and gel permeation chromatography are employed to evaluate the reaction rate and extent of these lard reaction. We find low activation energy (Ea) values that indicate that dextran with high molecular weight (HMD) exhibits a higher reaction rate with PL than that that of dextran with middle molecular weight (MMD) and low molecular weight (LMD). As for the functional characteristics of the formed conjugate, the conjugate of PL-HMD possesses a higher emulsifying activity, and PL-LMD exhibits higher antimicrobial activity than other molecular weight of dextran. We observe that long heating time at high temperatures can induce the partial degradation of the formed conjugates, which is reflected in the decreasing of the emulsifying and antimicrobial activity of PL-dextran conjugates.

A Hybrid Titanium-Softmaterial, High-Strength, Transparent Cranial Window for Transcranial Injection and Neuroimaging.

A transparent and penetrable cranial window is essential for neuroimaging, transcranial injection and comprehensive understanding of cortical functions. For these applications, cranial windows made from glass coverslip, polydimethylsiloxane (PDMS), polymethylmethacrylate, crystal and silicone hydrogel have offered remarkable convenience. However, there is a lack of high-strength, high-transparency, penetrable cranial window with clinical application potential. We engineer high-strength hybrid Titanium-PDMS (Ti-PDMS) cranial windows, which allow large transparent area for in vivo two-photon imaging, and provide a soft window for transcranial injection. Laser scanning and 3D printing techniques are used to match the hybrid cranial window to different skull morphology. A multi-cycle degassing pouring process ensures a good combination of PDMS and Ti frame. Ti-PDMS cranial windows have a high fracture strength matching human skull bone, excellent light transmittance up to 94.4%, and refractive index close to biological tissue. Ti-PDMS cranial windows show excellent bio-compatibility during 21-week implantation in mice. Dye injection shows that the PDMS window has a "self-sealing" to keep liquid from leaking out. Two-photon imaging for brain tissues could be achieved up to 450 µm in z-depth. As a novel brain-computer-interface, this Ti-PDMS device offers an alternative choice for in vivo drug delivery, optical experiments, ultrasonic treatment and electrophysiology recording.

Characteristics, treatments, and prognosis of a critical illness polyneuromyopathy patient with positive anti-GM1 after severe traumatic brain injury: A case report.

To investigate the clinical features, treatment and prognosis of critical illness polyneuromyopathy (CIPNM) in patients with severe traumatic brain injury (sTBI) who had positive anti-ganglioside GM1 (anti-GM1) antibody IgG. A case of CIPNM with positive anti-GM1 antibody IgG was retrospectively analysed and followed-up for 30 months. After 1 week of treatment with large dose of short-term glucocorticoid and human immunoglobulin, the muscle strength of both lower extremities was restored to grade 1. Three months later, the muscle strength and muscle tension of the patient's limbs returned to normal except for grade 3 of bilateral dorsal extensor muscle strength. In addition, the patient can walk alone with a waddling gait. After 30 months, there was no recurrence. The application of large dose of short-term glucocorticoid and human immunoglobulin to CIPNM that are positive for anti-GM1 antibodies may be an effective treatment.

A Study on Explosion Separation Technology of Carbon Fiber Reinforced Epoxy Resin-Based Composite Laminate.

In an aeroengine casing containment experiment, in order to explode and separate unidirectional carbon fiber reinforced epoxy resin-based laminate, with uneven thickness, without excessive residual speed and fragment spattering, blades were subjected to three types of blasting and cutting pretests, including normal and lateral opening charge explosive tests on the laminate and linear charge-shaped jet cutting. The linear charge-shaped method was found to be the most suitable method for separating the laminate. The finite-element analysis program AUTODYN was used to simulate and optimize the effect of shaped jet cutting. When the explosive height of the shaped jet cutter was set to 90 mm, the laminate broke with the least number of fragments and the residual velocity of the plate was the smallest. At this time, we obtained the relationship between the total amount of explosive and the thickness of the composite plate when the composite plates of different thicknesses were just broken, and the rationality of the relationship was verified by experiments. The research method, in this paper, provides a reference scheme to design explosive separation composite materials in complex engineering environments.

Oleic Acid (OA), A Potential Dual Contrast Agent for Postmortem MR Angiography (PMMRA): A Pilot Study.

Choosing proper perfusates as contrast agents is an important aspect for postmortem magnetic resonance angiography (PMMRA). However, in this emerging field, the number of suitable kinds of liquid is still very limited. The objective of this research is to compare MR images of oleic acid (OA) with paraffin oil (PO) in vitro and in ex situ animal hearts, in order to evaluate the feasibility to use OA as a novel contrast agent for PMMRA. In vitro, OA, PO and water (control) were introduced into three tubes separately and T1weighted-spin echo (T1w-SE) and T2w-SE images were acquired on a 1.5T MR scanner. In the second experiment, OA and PO were injected into left coronary artery (LCA) and left ventricle (LV) of ex situ bovine hearts and their T1w-SE, T2w-SE, T1w-multipoint Dixon (T1w-mDixon) and 3DT2w-mDixon images were acquired. The overall results indicate that OA may have a potential to be used as a dual (T1 and T2 based) contrast agent for PMMRA when proper sequence parameters are utilized. However, as the pilot study was based on limited number of animal hearts, more researches using OA in cadavers are needed to validate our findings.

Quantitative Reduction of Basilar Invagination: Correction Target of Clivo-Axial Angle.

STUDY DESIGN: A mechanism-based reasoning and case-control study. OBJECTIVE: To introduce correction target of clivo-axial angle (CXA) in quantitative surgical reduction of basilar invagination (BI). SUMMARY OF BACKGROUND DATA: The exact mechanism of BI with or without atlantoaxial dislocation is still unclear. Sagittal deformity is a key feature of BI. Correction of CXA directly influences subaxial cervical lordosis (increase of CXA equals the decrease of cervical lordosis). However, a quantitative reference for correction surgery has not been established. MATERIALS AND METHODS: CXA was divided by Chamberlain line into clivus tilt (CT) and axial tilt (AT). Patients diagnosed with BI were retrospectively included. Patients with degenerative cervical spine diseases or vascular diseases (without BI) were included as controls. CT, AT, and other common parameters were measured and analyzed with t test and multiple linear regression. Demonstration case was presented. RESULTS: A total of 42 BI patients and 23 controls were included. Normal references for CXA, AT, and CT were 162.3±7.1, 93.8±6.5, and 68.6±3.8 degrees, respectively. BI patients had a 30.3-degree smaller CXA, a 15.5-degree smaller AT, and a 14.9-degree smaller CT. Basal angle (P=0.002) independently had a significant influence on extent of BI, while CT and AT did not. Demonstration case showed that CT was fixed and correcting AT to an ideal 94 degrees was optimal for an individual patient. CONCLUSIONS: Proper quantitative correction of CXA needs to be individualized in consideration of CT and AT. The difference between actual AT and its ideal value (about 94 degrees) is the optimal target of CXA correction to decompress neural elements ventrally and recover better subaxial cervical lordosis. LEVEL OF EVIDENCE: Level IV.