Standard cardiopulmonary resuscitation versus chest compressions only after out-of-hospital cardiac arrest: a protocol for a systematic review and meta-analysis.

INTRODUCTION: The 2020 American Heart Association guidelines encourage lay rescuers to provide chest compression-only cardiopulmonary resuscitation to simplify the process and encourage cardiopulmonary resuscitation initiation. However, recent clinical trials had contradictory results about chest compression-only cardiopulmonary resuscitation. This study will aim to compare standard and chest compressions-only cardiopulmonary resuscitation after out-of-hospital cardiac arrest. METHODS AND ANALYSIS: This study will retrieve only randomised and quasi-randomised controlled trials from the Cochrane Library, PubMed, Web of Science and Embase databases. Data on study design, participant characteristics, intervention details and outcomes will be extracted by a unified standard form. Primary outcomes to be assessed are hospital admission, discharge, and 30-day survival, and return of spontaneous circulation. The Grading of Recommendations, Assessment, Development and Evaluation framework will evaluate the quality of evidence. Cochrane's tool for assessing the risk of bias will evaluate risk deviation. If the I2 statistic is lower than 40%, the fixed-effects model will be used for meta-analysis. Otherwise, the random-effects model will be used. The search will be performed following the publication of this protocol (estimated to occur on 30 December 2024). DISCUSSION: This study will evaluate the effect of chest compression-only cardiopulmonary resuscitation after out-of-hospital cardiac arrest and provide evidence for cardiopulmonary resuscitation guidelines. ETHICS AND DISSEMINATION: No patient or public entity will be involved in this study. Therefore, the study does not need to be ethically reviewed. The results of the study will be disseminated through peer-reviewed journal publications and committee conferences. PROSPERO REGISTRATION NUMBER: CRD42021295507.

Completely green and sustainable preparation of PVDF hollow fiber membranes via melt-spinning and stretching method.

In this work, the poly(vinylidene fluoride) (PVDF) hollow fiber membranes with switchable pore size were fabricated by melt-spinning and stretching (MS-S) process based on a completely green and sustainable route. The membrane preparation process and pore formation mechanism were discussed and investigated in detail. Meanwhile, the effect of stretching ratio on the membrane structure and property was studied based on scanning electron microscopy (SEM), pore size distribution, N2 flux, pure water flux, mechanical property and so on. The prepared membranes with different stretching ratios exhibited excellent tensile strength in the range from 23.0 to 62.6 MPa. The mean pore size of the prepared membranes with stretching 100 % (M-100) was about 0.317 µm, which showed a high dye rejection (<93.9 %) for Direct Black 19. Specifically, there were not any organic solvent and low-molecular-weight diluent used during the preparation process. The recycled PEO and water were obtained after treating the wastewater by membrane filtration. In addition, the recycled PEO could be reused as pore forming agent, which could achieve completely green and sustainable membrane preparation process.

Preparation of PSF/FEP mixed matrix membrane with super hydrophobic surface for efficient water-in-oil emulsion separation.

Polysulfone (PSF)/fluorinated ethylene propylene (FEP) mixed matrix membranes (MMMs) with super hydrophobic surface were successfully fabricated via non-solvent induced phase separation (NIPS) method. The effects of FEP content on the morphology, roughness, wettability, pore size, and mechanical property of PSF/FEP MMMs were characterized by scanning electron microscope, confocal microscopy, contact angle goniometer, mercury porosimetry, and tensile testing instrument, respectively. When the FEP content was 9 wt%, the average roughness of M-4 reached 0.712 µm. Meanwhile, the water contact angle (CA) and the water sliding angle (SA) was 153.3° and 6.1°, respectively. M-4 showed super hydrophobicity with a micro- and nanoscale structure surface. Then, M-4 was used for separating of water-in-oil emulsion, showing high separation efficiency for water-in-kerosene and water-in-diesel emulsions of 99.79% and 99.47%, respectively. The flux and separation efficiency changed slightly after 10 cycles. Therefore, this study indicated that the obtained PSF/FEP MMM with super hydrophobic surface could be used for efficient water-in-oil emulsion separation.

Evolution of polyvinylidene fluoride (PVDF) hierarchical morphology during slow gelation process and its superhydrophobicity.

In the paper, we proposed an evolution process of polyvinylidene fluoride (PVDF) macromolecular aggregation in a mixed solvent through the simple and slow gelation process at room temperature. The mixed solvent is prepared with a room-temperature solvent and a high-temperature solvent. The evolution process can be terminated by quenching and exchanging with nonsolvent in a nonsolvent coagulation bath properly, and then the vivid petal-like nanostructure and microspherulite is formed simultaneously. This hierarchical morphology endows PVDF with superhydrophobic and self-cleaning properties, which is useful to PVDF coating and membrane materials. The evolution processes are investigated through the measurements of differential scanning calorimetry (DSC), X-ray diffraction (XRD). In addition, the rheological properties of solution, dry gel and wet gel, are explored.