[en] Poly(L-lactide) (PLLA) porous materials have become increasingly important for practical applications. However, the methods for preparing PLLA-based porous particles are quite limited. The chirality of PLLA materials remains scarcely explored even though PLLA is a well-known chiral polymer. In this paper, we establish an unprecedented, facile approach for preparing PLLA particles with lamellar structures by precipitation polymerization. By adjusting polymerization conditions (solvent and temperature), a series of PLLA particles with tunable morphology was fabricated. The resulting particles were characterized by SEM, CD, XRD, DSC, and GPC measurements. We further explored chiral resolution ability of the PLLA particles used as chiral additive to induce enantioselective crystallization. According to SEM, CD, and XRD characterizations, PLLA particles show considerable enantioselectivity and preferentially induce L-threonine to crystallize from the racemic solution. Besides, enhancing the crystallinity of PLLA particles is beneficial for improving the particles’ enantiodifferentiating ability. The present study provides a versatile platform for developing novel PLLA materials, which deserve more attention as chiral biomaterials.

[en] Objective: To explore the feasibility, safety and effect of endovascular revascularization for chronic long segment internal carotid artery occlusion. Methods: The cases of chronic long segment internal carotid artery occlusion who were treated by endovascular revascularization in our center from May 2015 to April 2017 were reviewed. Eleven cases met the inclusion criteria: the duration of the occlusion was more than three weeks and the segment of the occlusion was beyond the petrosal segment of internal carotid arteries from the initial segment. All of the cases had the related symptoms and had declining cerebral perfusion. The analysis index included: baseline information, radiological information, perioperative results, clinical follow-up and imaging follow-up. The imaging follow-up index were the re-stenosis or re-occlusion of the revascularized artery. Results: The occlusion was recanalized successfully in 9 of 11 patients, the two procedures were abandoned after repeated attempts and the guide wire could not reach the true lumen when navigating in the cavernous segment. Six cases of the nine successfully recanalized cases accepted perfusion-weighted imaging scan. Cerebral perfusion of all the cases were improved. Thrombus shifting was observed in one case and occluded a subbranch, mechanical thrombectomy was performed successfully, the case was recovered well without sequela. No symptomatic stroke or death was happened in the perioperative period. All of the nine cases who successfully recanalized acquired clinical follow-up, median follow-up time was ten months (4-28 months). No ischemic stroke and death happened after the procedures. Seven of nine cases improved in the clinical symptoms. Five cases accepted the imaging follow-up. The meantime was six months. No re-occlusion was happened. Conclusions: Endovascular revascularization for chronic long segment internal carotid artery occlusion is feasible, safe, and short-term effective. More clinical research is needed to verify the long-term effect. (authors)

[en] Highlights: • A new equivalent model with high accuracy over full-range SOC is proposed. • The electrochemical processes are approximately described in the model. • Online parameters identification is applied to increase the adaption of the model. • The model is suitable for application to battery state estimation in BMS. -- Abstract: State estimation is a key issue of battery management system (BMS) to improve the energy utilization of lithium-ion battery in electric vehicle, the performance of which relies on the accuracy of equivalent model over full-range sate of charge (SOC). However, the widely applied equivalent circuit model (ECM) has limitations at low SOC range. In this paper, an optimized equivalent model is proposed combining the lithium-ion battery internal electrochemical processes with the ECM. For one thing, the proposed model is able to offer high accuracy by considering solid-phase diffusion into the update of open circuit voltage (OCV) and describing the polarization at the solid-liquid interface from the electrochemical perspective. For another thing, the proposed approximate method for describing internal electrochemical micro-variables with external electric macro-variables allows the model to avoid a series of partial differential equations. In addition, online parameter identification based on the forgetting factor based recursive least square method (FFRLS) makes the proposed model well-adapted to dynamic working conditions. Compared with the ECM under multiple working conditions, the proposed model is proven to provide a better performance over full-range SOC especially at the low-range area below 20%.

[en] Objective: To evaluate the feasibility, safety and efficacy of the treatment of chronic symptomatic internal carotid artery long-segmental occlusion. Methods: Fifty-one cases of chronic symptomatic internal carotid artery long-segmental occlusion (arterial occlusion more than 2 anatomical segments) who were treated with hybrid surgery (plaque located at the carotid sinus) or endovascular revascularization (plaque located at the distal end of the internal carotid artery occlusion) from May 2015 to May 2018 were reviewed. Recanalization, perioperative complications, stroke events, and reocclusion events during the follow-up period were recorded. Results: The occlusion was recanalized successfully in 45 of 51 patients (88.2%, 45/51), 6 patients failed because the guidewire could not cross the distal arterial occlusion. And the technical success rate was 96.0% (24/25) in hybrid surgery and 80.8% (21/26) in endovascular revascularization. Perioperative complications occurred in 2 patients who underwent combined endovascular treatment. One patient had a small branch embolism due to intraoperative thrombus shift, and 1 patient had large area cerebral infarction. The complications occurred in 2 patients who underwent hybrid surgery, including 1 case of internal carotid cavernous fistula and 1 case of acute reocclusion of internal carotid artery. Forty-four patients with successful operation received clinical follow-up, with the median follow-up time of 24 months (7-43 months). No recurrent stroke and death occurred during the follow-up period. Clinical symptoms were improved in 34 cases. Totally 44 patients received imaging follow-up, and during the median imaging follow-up time of 8 month (4-28 months), 6 cases had reocclusion, and 2 cases had restenosis. Conclusion: The treatment of chronic symptomatic internal carotid artery long-segmental occlusion is technically feasible and safety with good short-term efficacy. However, its exact efficacy remains to be confirmed by long-term follow-up studies with large samples. (authors)

[en] As a non-magnetic heavy metal is attached to a ferromagnet, a vertically flowing heat-driven spin current is converted to a transverse electric voltage, which is known as the longitudinal spin Seebeck effect (SSE). If the ferromagnet is a metal, this voltage is also accompanied by voltages from two other sources, i.e., the anomalous Nernst effect in both the ferromagnet and the proximity-induced ferromagnetic boundary layer. By properly identifying and carefully separating those different effects, we find that in this pure spin current circuit the additional spin current drawn by the heavy metal generates another significant voltage by the ferromagnetic metal itself which should be present in all relevant experiments

[en] In order to prolong the shelf life of Chinese traditional dry-cured meat products, a pulsed ultraviolet light (PL-UV) irradiation method was adopted to treat meat products according to the following parameters: pulse energy of 8 J, 300 pulses, and an effective exposure distance of 10 cm; the UV light irradiation power of 6 W, an effective exposure distance of 11 cm, and an exposure period of 5 min. After a pulsed ultraviolet irradiation, total bacterial count in dry-cured meat decreased from 6.89 to 4.53 lg (CFU/g). The number of Micrococcus and Staphylococcus in samples decreased from 6.49 to 4.10 lg (CFU/g) and the number of molds and yeasts decreased from 5.45 to 4.28 lg (CFU/g). The number of Lactic acid bacteria increased from 3.97 to 4.55 lg (CFU/g) and Escherichia coli was not detected. Total colonies, target bacteria, peroxide value, thiobarbituric acid-reactive substances, water activity, T₂ relaxation time, pH, color difference, total volatile basic nitrogen, and the sensory evaluations of dry-cured meat products after PL-UV treatments were determined in a 30-d storage experiment. The shelf life of dry-cured meat treated with PL-UV irradiation at 20 °C was predicted to reach to 294 d by applying of shelf life testing method accelerated. The quality and safety of dry-cured meat treated with PL-UV irradiation was better than that of untreated samples.

[en] It is a crucial factor for enhancing upconversion luminescence (UCL) by doping different metals under irradiation. In this article, a series of Na₃Gd(VO₄)₂:Ln³⁺ (NGVO:Ln³⁺) were prepared by sol-gel means with citrate and characterized using X-ray diffraction. Their UCL properties were systematically investigated. A wide multi-colour emission corresponding to different Ln³⁺ (Yb³⁺/Er³⁺/Tm³⁺/Ho³⁺) doping was obtained under single-wavelength excitation. It is worth pointing out that among all the studied samples, only the UCL intensity of NGVO:15%Yb³⁺/2%Er³⁺ was 1.74 times more than that of the sum under the excitation at 980 and 1550 nm due to the synergistic effect under simultaneous 980 and 1550 nm excitation. Interestingly, a higher S_a (5.54 x 10^-3 K^-1) for NGVO:15%Yb³⁺/2%Er³⁺ excited at 1550 nm could be obtained, which had an advantage over that at 980 nm excitation. The possible energy transfer mechanism of NGVO:15%Yb³⁺/2%Er³⁺ under single- and multi-wavelength excitation was also discussed in detail using an energy level diagram. To further improve the UCL intensity, NGVO:15%Yb³⁺/2%Er³⁺ doped with other rare-earth ions (La³⁺/Lu³⁺/Y³⁺) were synthesized, and their UCL intensity and Sa values were also improved to a certain extent. (author)

[en] Highlights: • Investigate Ni speciation in practical electroless nickel plating effluent • Amount of smaller-sized Ni-bearing complexes increased along the treatment process. • Assess Ni speciation with proposed chemical formulae along the treatment scheme • Suggest the feasible post-treatment program for the refractory residual Ni -- Abstract: The electroless nickel (EN) industry has suffered from the reduction in Ni concentration to lower than 0.1 mg/L. Hence, Ni speciation along a typical sequential treatment scheme has important implications to optimize the design of advanced treatment. For the first time, we revealed the Ni speciation in segmented EN outfall effluents by virtue of multiple analytical methods. After ensuring all the Ni-bearing complexes were completely dissolved by size-fractioned ultrafiltration trials, customized mass spectra analysis was conducted. In a series of ICP-MS assays, the potential polyatomic interfering species was primarily excluded. The chromatography hyphenated IC-ICP-MS and SEC-ICP-MS results demonstrated that the dominant Ni species in the EN effluents was similar to EDTA-Ni but with a smaller size. The LC-MS experiment further distinguished several typical Ni-bearing complexes. Although Ni concentration declined continuously along the treatment scheme, the number of detected Ni-bearing complexes gradually increased but with lower molecular weights. Most of the detected mononuclear complexes had higher indexes of hydrogen deficiency (IHD) than EDTA-Ni, whereas it was believed that the similar stereo ring shape was widespread in the EN effluent. Considering the efficient Ni decrease after the Fenton unit, further post-treatment approaches featuring higher active radical yields were suggested.

[en] Objective: To prepare a new thrombus model by fluid model method, which is suitable for evaluation of mechanical thrombectomy devices for acute stroke. Methods: The fluid model adopted the Chandler loop theory, while the static model adopted conventional method. Mechanical properties of thrombi prepared by fluid model and static model were measured by manual elongation test (15 samples in each group) and catheter injection test (15 samples in each group). Histological structure was compared among the above thrombus models (5 samples in each group) and specimens of five patients with stroke by hematoxylin-eosin staining method. Then, thrombi in fluid model were utilized to establish embolization of vessels in swine model (two pigs) for evaluation of radiopacity. Independent-Sample test was performed to compare the maximum tensile length of two methods, and Fisher's exact test was used to compare the rate of thrombus fragmentation after catheter injection test. Results: The maximum tensile length of two models were (4.28 ± 0.23) and (3.16 ± 0.13) cm, respectively, and the difference was statistically significant (t = 16.38, P < 0.01); After catheter injection, the fracture rates of thrombus were 13% (2/15) and 60% (9/15), which were also statistically significant (P < 0.05). As to histological structure, thrombi prepared by fluid model showed mixed thrombus structure, which similar to thrombi of stroke patients, But thrombi prepared by static model were replete with erythrocytes under the microscope. A total of eight vessels (lingual arteries and superficial cervical arteries) in two swines were successfully occlusive (TIMI 0 or 1), and sufficient radiopacity of each injected thrombus was observed. Conclusions: The thrombi prepared by fluid model not only have good mechanical stability and sufficient radiopacity, but their histological structure is similar to thromboemboli retrieved from cerebral arteries of patients with acute stroke. (authors)

[en] Lithium difluorophosphate (LiPO₂F₂) was used as an electrolyte additive to promote the low temperature performance of LiNi_0.5Co_0.2Mn_0.3O₂/graphite cells. The impact of LiPO₂F₂ on the solid electrolyte interface (SEI) film-formation on electrodes was demonstrated by various electrochemical methods and microscopy techniques, such as transmission electron microscopy (TEM), scanning electron microscope (SEM) as well as X-ray photoelectron spectroscopy (XPS), in the pouch cells and half cells. The results showed that the cells containing 1% LiPO₂F₂ performed 71.9% (−20 °C) and 57.93% (−30 °C) of initial capacity, while the cells without LiPO₂F₂ discharged only 49.41% and 9.6% of initial capacity under the same condition. In addition, the enhancement of cyclic performance at 0 °C was attributed to a conductive and stable SEI film formed on the graphite by the sacrifice of LiPO₂F₂, which led to a low impedance and richer content of LiF and Li₂CO₃ in SEI components, as depicted in XPS.