Sulfonate-modified fullerenes mimicking tentacle structures for humidity sensors.

In this work, a straightforward method for synthesizing fullerene derivatives with tentacle structures has been explored for monitoring environmental humidity, which involves introducing sulfonate onto the fullerenes. The structure and number of polar groups in three fullerene derivatives determined by a series of structural tests greatly affect their hydrophilicity and morphology, resulting in changes in humidity sensitive properties. In particular, the hysteresis and response time of the sensors display a great correlation with hydrophilicity. C60-Ho, the best performing derivative of this work, has exhibited high response values (∼3500 times), good linearity (R2 = 97.3 %), and rapid response/recovery times (0.3/4.4 s), making it suitable for various applications such as non-contact detection of respiration, finger distance, and soil humidity.

A Review of Ultrafine-Grained Magnetic Materials Prepared by Using High-Pressure Torsion Method.

High-pressure torsion (HPT) is a severe plastic deformation technique where a sample is subjected to torsional shear straining under a high hydrostatic pressure. The HPT method is usually employed to create ultrafine-grained nano-structures, making it widely used in processing many kinds of materials such as metals, glasses, biological materials, and organic compounds. Most of the published HPT results have been focused on the microstructural development of non-magnetic materials and their influence on the mechanical properties. The HPT processing of magnetic materials and its influence on the structural and magnetic properties have attracted increasing research interest recently. This review describes the application of HPT to magnetic materials and our recent experimental results on Mn3O4, Mn4N, and MnAl-based alloys. After HPT, most magnetic materials exhibit significantly reduced grain size and substantially enhanced coercivity.

Is Admission Lipoprotein-Associated Phospholipase A2 a Novel Predictor of Vasospasm and Outcome in Patients With Aneurysmal Subarachnoid Hemorrhage?

BACKGROUND: The relationships between lipoprotein-associated phospholipase A2 (Lp-PLA2) level, vasospasm, and clinical outcome of patients with aneurysmal subarachnoid hemorrhage (aSAH) are still unclear. OBJECTIVE: To identify the associations between admission Lp-PLA2 and vasospasm following subarachnoid hemorrhage and the clinical outcome of aSAH. METHODS: A total of 103 aSAH patients who had Lp-PLA2 level obtained within 24 h postbleeding were included. The relationships between Lp-PLA2 level, vasospasm, and clinical outcome were analyzed. RESULTS: Vasospasm was observed in 52 patients (50.49%). Patients with vasospasm had significantly higher Lp-PLA2 level than those without (P < .001). Both modified Fisher grade (P = .014) and Lp-PLA2 level (P < .001) were significant predictors associated with vasospasm. The Z test revealed that power of Lp-PLA2 was significantly higher than that of modified Fisher grade in predicting vasospasm (Z = 2.499, P = .012). At 6-mo follow-up, 44 patients (42.72%) had unfavorable outcome and 36 patients (34.95%) died. The World Federation of Neurosurgical Societies (WFNS) grade and Lp-PLA2 level were both significant predictors associated with 6-mo unfavorable outcome and mortality (all P < .001). The predictive values of Lp-PLA2 for unfavorable outcome and mortality at 6-mo tended to be lower than those of the WFNS grade, but the differences were not statistically significant (P = .366 and 0.115, respectively). Poor-grade patients having Lp-PLA2 > 200 µg/L had significantly worse 6-mo survival rate than poor-grade patients having Lp-PLA2 ≤ 200 µg/L (P = .001). CONCLUSION: The Lp-PLA2 might be useful as a novel predictor in aSAH patients. A total of 30 poor-grade patients; those with elevated Lp-PLA2 level have higher risk of 6-mo mortality compared to those without.

The prevalence of freezing of gait in Parkinson's disease and in patients with different disease durations and severities.

BACKGROUND: The prevalence rates of freezing of gait (FOG) in Parkinson's disease (PD) vary widely, ranging from 14.0 to 55.1%. Our aim is to calculate the overall prevalence of FOG in all PD patients with different disease durations and severities. METHODS: Using Medline/PubMed/Embase, we carried out a systematic literature search for studies reporting the PD and clinically relevant FOG. RESULTS: After primary screening, a total of 35 studies were identified and further analyzed for inclusion into the analysis, and 29 studies fulfilled the quality criteria and included in this meta-analysis. The overall prevalence of FOG in PD was 39.9% (95% CI 35.3-44.5%). The FOG identified by the freezing of gait questionnaire item 3 may be more prevalent (43.8%, 95% CI 38.5-49.1%) than the FOG identified by the Unified Parkinson's Disease Rating Scale item 14 (36.0%, 95% CI 29.0-43.1%). Disease duration and severity are both the clinical features associated with the FOG. The highest FOG prevalence rate in PD patients was seen in patients with disease durations ≥ 10 years, at 70.8%, followed that of PD patients with disease durations ≥ 5 years (53.3%), and PD patients with disease durations < 5 years (22.4%). FOG presented in 28.4% of PD patients with Hoehn and Yahr staging (H&Y) score ≤ 2.5, and in 68.4% of PD patients with H&Y score ≥ 2.5. CONCLUSION: This meta-analysis confirms that the prevalence of FOG in PD is considerable, and highlights the need for accurate identification of FOG in PD.

Predictive factors of postoperative infection-related complications in adult patients with cerebral cavernous malformations.

Postoperative infection is an important factor contributing to poor prognosis after surgical treatment of cerebral cavernous malformations (CCM). However, the predictive factors of postoperative infection-related complications in adult patients with CCM have still not been well established. To identify possible predictive factors of postoperative infection after CCM surgery, we retrospectively evaluated the data of CCM patients who were enrolled into our prospective registry database. The relationship between preoperative characteristics of patients and postoperative infection-related complications was analyzed. A total of 167 CCM patients were included in this study. The average age was 39.69 ± 15.27 years old, and 21 of them had postoperative infection. For patients with postoperative infection, the Glasgow Coma Scale (GCS), Modified Rankin Scale (mRS), white blood cell (WBC) count, and neutrophil (NEU) count were all significantly higher than those of the group without infection. Our preliminary results showed that NEU count might have significant predictive value of intracranial infection, and GCS, mRS and CCM presenting with hemorrhage were all factors significantly related to postoperative pneumonia. Preoperative GCS, mRS and CCM presenting with hemorrhage might be used as predictive factors for postoperative pneumonia after CCM surgery, while preoperative NEU count can be used as an important predictive factor for postoperative intracranial infection after CCM surgery. Further large-scale studies are still needed to confirm this finding.

Assessment of lipoprotein-associated phospholipase A2 level and its changes in the early stages as predictors of delayed cerebral ischemia in patients with aneurysmal subarachnoid hemorrhage.

OBJECTIVE: The relationship between lipoprotein-associated phospholipase A2 (Lp-PLA2) and various cardiovascular and cerebrovascular diseases is inconsistent. However, the connection between Lp-PLA2 level and delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH) remains unclear. The objective of this study was to investigate the relationships between the Lp-PLA2 levels in the early stages of aSAH and the occurrence of DCI. METHODS: The authors evaluated 114 patients with aSAH who were enrolled into a prospective observational cohort study. Serum Lp-PLA2 level at admission (D0), on the first morning (D1), and on the second morning of hospitalization (D2) were determined using commercial enzyme-linked immunosorbent assay kits. The relationship between Lp-PLA2 levels and DCI was analyzed. RESULTS: Forty-three patients with aSAH (37.72%) experienced DCI. Mean serum Lp-PLA2 level decreased from 183.06 ± 61.36 µg/L at D0 (D0 vs D1, p = 0.303), to 175.32 ± 51.49 µg/L at D1 and 167.24 ± 54.10 µg/L at D2 (D0 vs D2, p = 0.040). The Lp-PLA2 level changes (D0-D1 and D0-D2) were comparable between patients with and without DCI. Multivariate model analysis revealed Lp-PLA2 level (D0) > 200 µg/L was a more significant factor of DCI compared with Lp-PLA2 (D1) and Lp-PLA2 (D2), and was a strong predictor of DCI (odds ratio [OR] 6.24, 95% confidence interval [CI] 2.05-18.94, p = 0.001) after controlling for World Federation of Neurosurgical Societies (WFNS) grade (OR 3.35, 95% CI 1.18-9.51, p = 0.023) and modified Fisher grade (OR 6.07, 95% CI 2.03-18.14, p = 0.001). WFNS grade (area under the curve [AUC] = 0.792), modified Fisher grade (AUC = 0.731), and Lp-PLA2 level (D0; AUC = 0.710) were all strong predictors of DCI. The predictive powers of WFNS grade, modified Fisher grade, and Lp-PLA2 (D0) were comparable (WFNS grade vs Lp-PLA2: p = 0.233; modified Fisher grade vs Lp-PLA2: p = 0.771). The poor-grade patients with Lp-PLA2 (D0) > 200 µg/L had significantly worse DCI survival rate than poor-grade patients with Lp-PLA2 (D0) ≤ 200 µg/L (p < 0.001). CONCLUSIONS: The serum level of Lp-PLA2 was significantly elevated in patients with DCI, and decreased within the first 2 days after admission. Lp-PLA2 in the early stages of aSAH might be a novel predictive biomarker for the occurrence of DCI.

Beating Thermal Deterioration of Magnetization with Mn4C and Exchange Bias in Mn⁻C Nanoparticles.

The magnetization of most materials decreases with increasing temperature due to thermal deterioration of magnetic ordering. Here, we show that Mn4C phase can compensate the magnetization loss due to thermal agitation. The Mn⁻C nanoparticles containing ferrimagnetic Mn4C and other Mn⁻C/Mn-O phases were prepared by using the traditional arc-discharge method. A positive temperature coefficient of magnetization (~0.0026 Am² kg-1 K-1) and an exchange bias up to 0.05 T were observed in the samples. We ascribe the exchange bias to the co-existence of ferrimagnetic Mn4C/Mn3O4 and antiferromagnetic α-Mn(C)/MnO phases. The positive temperature coefficient of magnetization of the samples was ascribed to the presence of Mn4C phase, which is considered as a Néel's P-type ferrimagnet.

In situ Observation of Phase Transformation in MnAl(C) Magnetic Materials.

The phase transformation in two modes, including both displacive and massive growth of τ-phase from ε-MnAl(C), was observed by in situ transmission electron microscopy. The exact temperature range for different phase transformation modes was determined by magnetic measurements. The displacive growth of ε→τ in Mn54Al46 (or Mn54Al46C2.44) occurs at temperatures below 650 K (or 766 K), above which both modes coexist. One-third or less of the ε-phase can be transformed into τ-phase via displacive mode while the remaining two-thirds or more via massive mode. In bulk τ-phase, most τ-nanocrystals formed via displacive mode are distributed in the matrix of large τ-grains that formed via massive mode. The typical massive growth rate of the τ-phase is 8-60 nm/s, while the displacive growth rate is low. A more complete understanding of the ε→τ phase transformations in the MnAl-based magnets was provided in this work, based on which the annealing process for ε→τ was optimized and thus high purity τ-phase with high saturation magnetization was obtained.

Study of transport behavior for Fe-doping La(0.67)Ca(0.33)MnO3 perovskite manganese.

Systematic studies of the transport properties of La(0.67)Ca(0.33)Mn(1-x)Fe(x)O3 (x=0-0.3) systems showed that with increasing Fe-doping content x the resistance increases and the insulator-metal transition temperature moves to lower temperature. For small doping content, the transport property satisfies metal transport behavior below the transition temperature, and above the transition temperature it satisfies the small polaron model. This behavior can be explained by Fe3+ doping, which easily forms Fe(3+)-O(2-)-Mn4+ channel, suppressing the double exchange Mn(3+)-O(2-)-Mn4+ channel and enhancing the spin scattering of Mn ions induced by antiferromagnetic clusters of Fe ions.