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.

Synergistic effects ofα-Fe2O3nanoparticles and Fe-doping on gas-sensing performance of NiO nanowires and interface mechanism

High surface area nickel oxide nanowires (NiO NWs), Fe-doped NiO NWs andα-Fe₂O₃/Fe-doped NiO NWs were synthesized with nanocasting pathway, and then the morphology, microstructure and components of all samples were characterized with XRD, TEM, EDS, UV-vis spectra and nitrogen adsorption-desorption isotherms. Owing to the uniform mesoporous template, all samples with the same diameter exhibit the similar mesoporous-structures. The loadedα-Fe₂O₃nanoparticles should exist in mesoporous channels between Fe-doped NiO NWs to form heterogeneous contact at the interface of n-typeα-Fe₂O₃nanoparticles and p-type NiO NWs. The gas-sensing results indicate that Fe-dopant andα-Fe₂O₃-loading both improve the gas-sensing performance of NiO NWs sensors.α-Fe₂O₃/Fe-doped NiO NWs sensors presented the highest response to 100 ppm ethanol gas (55.264) compared with Fe-doped NiO NWs (24.617) and NiO NWs sensors (3.189). The donor Fe-dopant increases the ground state resistance and the absorbed oxygen content in air.α-Fe₂O₃nanoparticles in electron depletion region result in the increasing resistance in ethanol gas and decreasing resistance in air. In this way,α-Fe₂O₃/Fe-doped NiO NWs sensor presents the excellent gas-sensing performance due to the formation of heterogeneous contact at the interface.

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.

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.

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.

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 Mn₅₄Al₄₆C_2.44) 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.

dCTP pyrophosphohydrase exhibits nucleic accumulation in multiple carcinomas

Nucleoside triphosphate pyrophosphohydrolase (NTP-PPase) functions as one of the mechanisms to guarantee the fidelity of DNA replication through the cleavage of non-canonical nucleotides into di- or monophosphates. Human NTP-PPase is poorly understood and investigated. In the present study, by using tissue microarrays with the paired cancer and adjacent regions, we found that with the prevalent expression of dCTP pyrophosphohydrase (DCTPP1) in the cytosol and nucleus in tumors investigated, DCTPP1 was inclined to accumulate in the nucleus of cancer cells compared to the paired adjacent tissue cells in multiple carcinomas including lung, breast, liver, cervical, gastric and esophagus cancer. More significantly, the higher DCTPP1 expression in the nucleus of lung, gastric and esophagus cancer cells was associated with histological subtypes. The nucleic accumulation of DCTPP1 was apparently observed as well when tumor cell line MCF-7 was treated with H₂O₂in vitro. Considering the roles of DCTPP1 on restricting the concentration of non-canonical nucleotides in the nucleotide pool, accumulation of DCTPP1 in the nucleus of tumor cells might suffice for maintaining the proper DNA replication in order to fulfill the requirement for the survival and proliferation of tumor cells.

Magnetic stability of SnO₂ nanosheets

Room temperature ferromagnetism has been observed in freshly synthesized and post-annealed SnO₂ nanosheets. The results of x-ray diffraction and x-ray photoelectron spectroscopy reveal that the newly synthesized samples and those annealed at 400 °C under either an O₂ or Ar atmosphere possess rutile structure and no other impurity phases are observed. The fitting results of the O 1s and Sn 3d spectra from SnO₂ samples annealed at 400 °C under an O₂ or Ar atmosphere both indicate that oxygen vacancies inevitably exist in these samples. It is found that the saturation magnetization of all the annealed samples does not feature mono-dependence on oxygen vacancies, whereas an Sn vacancy related origin seems more plausible to account for variations in the magnetization of samples studied. This finding corresponds to first-principle calculation results from our previous work. Furthermore, the Curie temperature of SnO₂ nanosheets was estimated to be around 300 °C, rendering it a very good option for the next generation of spintronics.

Attenuation of ischemia-induced mouse brain injury by SAG, a redox-inducible antioxidant protein

Cerebral ischemia resulting from a disruption of blood flow to the brain initiates a cascade of events that causes neuron death and leads to neurologic dysfunction. Reactive oxygen species are thought, at least in part, to mediate this disease process. The authors recently cloned and characterized an antioxidant protein, SAG (sensitive to apoptosis gene), that is redox inducible and protects cells from apoptosis induced by redox agents in a number of in vitro cell model systems. This study reports a neuroprotective role of SAG in ischemia/reperfusion-induced brain injury in an in vivo mouse model. SAG was expressed at a low level in brain tissue and was inducible after middle cerebral artery occlusion with peak expression at 6 to 12 hours. At the cellular level, SAG was mainly expressed in the cytoplasm of neurons and astrocytes, revealed by double immunofluorescence. An injection of recombinant adenoviral vector carrying human SAG into mouse brain produced an overexpression of SAG protein in the injected areas. Transduction of AdCMVSAG (wild-type), but not AdCMVmSAG (mutant), nor the AdCMVlacZ control, protected brain cells from ischemic brain injury, as evidenced by significant reduction of the infarct areas where SAG was highly expressed. The result suggests a rather specific protective role of SAG in the current in vivo model. Mechanistically, SAG overexpression decreased reactive oxygen species production and reduced the number of apoptotic cells in the ischemic areas. Thus, antioxidant SAG appears to protect against reactive oxygen species-induced brain damage in mice. Identification of SAG as a neuroprotective molecule could lead to potential stroke therapies.

[Isolation of a gene related to trichosanthin-induced apoptosis (GRETA)]

Disturbance of the apoptosis-related signaling pathway is regarded as one of the critical factors for tumorigenesis. Isolation of the genes involved in the process of apoptosis would be thereby helpful to explore the mechanism of tumor transformation and to develop novel therapeutic approaches. Here we report a gene fragment GRETA, the gene related to trichosanthin-induced apoptosis, isolated from a leukemia cell line U937 undergoing apoptosis induced by a plant protein Trichosanhin (TCS). A 293bp segment of GRETA was revealed to be 78.3% homologous to Bruton's tyrosine kinase at nucleic acid level. And Northern blot analysis showed that three messengers of RNA with the size of about 0.8-kb, 2.0-kb and 7.0-kb, respectively, were detected in TCS-untreated U937 cells when probed with GRETA, but there were only 0.8-kb and 2.0-kb transcripts appeared in apoptotic U937 cells. In addition, the abundance of each transcript changed apparently. The 0.8-kb transcript, for example, was the main band in Northern analysis in apoptotic U937 cells while was only detected marginally in TCS-untreated cells. These data suggested a possible relationship between the alternative splicing patterns of GRETA and the apoptosis.

Expression of tumor necrosis factor-alpha and intercellular adhesion molecule-1 after focal cerebral ischemia in interleukin-1beta converting enzyme deficient mice

Interleukin-1beta (IL-1beta) is expressed after cerebral ischemia and blocking its action reduces subsequent ischemic brain injury. However, the mechanisms by which IL-1beta affects ischemic brain are not understood. To investigate the role of IL- 1beta in regulation of tumor necrosis factor-alpha (TNF-alpha) and intercellular adhesion molecule-1 (ICAM-1) during focal cerebral ischemia, the authors studied mutant mice deficient in the IL-1 converting enzyme (ICE) gene (ICE knockout [KO] mice). Ninety-four adult male ICE KO and wild-type mice underwent 3, 6, 12, and 24 hours of permanent middle cerebral artery occlusion using the suture method. Expression of TNF-alpha and ICAM-1 protein in ischemic brain was examined using immunohistochemistry and Western blot analysis. Neither ICE KO nor wild-type mice had significant differences in CBF and body temperature measurements during the ischemic procedure. TNF-alpha expression increased in the ipsilateral hemisphere after 3 hours of occlusion, peaked at 12 hours and decreased at 24 hours of ischemia in both ICE KO and wild-type mice. ICAM-1 immunohistochemistry showed that the number of ICAM-1-positive vessels in the ischemic hemisphere was reduced in ICE KO mice (P < .05). Western blot analysis showed that ICAM-1 protein expression was significantly attenuated in the ipsilateral hemisphere in the ICE KO mice, which paralleled the immunohistochemistry results. The authors' results indicate that TNF-alpha expression is increased in both ICE KO and wild-type mice suggesting that TNF-alpha expression is not related to or upregulated by IL-1beta . ICAM-1 expression is significantly reduced in the ICE KO mice suggesting that IL-1beta plays an important role in the upregulation of adhesion molecules during focal cerebral ischemia.

Expression of intercellular adhesion molecule 1 (ICAM-1) is reduced in permanent focal cerebral ischemic mouse brain using an adenoviral vector to induce overexpression of interleukin-1 receptor antagonist

Our previous studies have demonstrated that overexpression of recombinant human interleukin-1 receptor antagonist protein (IL-1ra) via gene transfer can reduce ischemic brain injury. However, the mechanism of action of IL-1ra in ischemia is unclear. Since interleukin-1 can up-regulate intercellular adhesion molecules in endothelium, the present study was designed to determine whether overexpression of the IL-1ra can reduce the expression of intercellular adhesion molecule-1 (ICAM-1) after ischemic injury. Normal saline or adenovirus vector (1x109 particles) encoding the human IL-1ra gene (Ad.RSVIL-1ra) or the Escherichia coli LacZ gene (Ad.RSVlacZ) was injected into the right lateral cerebral ventricle of adult CD-1 mice. After five days, permanent middle cerebral artery occlusion (MCAO) was achieved for 24 h using an intraluminal suture. Cerebral blood flow was monitored by transcranial laser Doppler flowmetry to verify the occlusion. ICAM-1 protein was quantified using Western blot analysis and localized using immunohistochemistry. After MCAO, surface blood flow in the ischemic hemisphere was decreased to 9-11% of the baseline. There were fewer ICAM-1 positive vessels in the ischemic cortex of the Ad.RSVIL-1ra transfected mice than in the Ad.RSVlacZ transfected and saline treated mice (138+/-19 vs. 249+/-25, 284+/-22, p<0.05). Western blot analysis shows that ICAM-1 protein decreased 50-60% in the Ad. RSVIL-1ra group compared to the other two groups. There were no significant differences in the numbers of positive vessels in the ischemic basal ganglia and contralateral hemisphere among the three groups. Our studies suggest that IL-1ra overexpression can down-regulate the expression of ICAM-1 in the ipsilateral cortex in ischemic mice. Interleukin-1 may play an important role in the activation of inflammatory reaction during focal cerebral ischemia by promoting leukocyte adhesion on the endothelium cells.

Diagnostic role of gadolinium-DTPA in pediatric neuroradiology. A retrospective review of 655 cases

We retrospectively reviewed the findings in 655 consecutive young patients who underwent contrast-enhanced MR examinations (1.5T) of the head or spine. Their ages ranged from 4 months to 20 years (mean 10 years). There was a 1.7% incidence of minor adverse reactions to gadolinium (Gd)-DTPA, none of which required treatment; no serious adverse reactions were encountered. Based on the radiologic diagnosis the patients were divided into three groups: (1) normal, (2) CNS neoplasm, (3) abnormal but not neoplasm. There were 178 patients thought to have CNS neoplasms and of these 156 (88%) enhanced. Of 124 histologically confirmed neoplasms 115 (93%) showed enhancement after Gd-DTPA. Eight children had histologically confirmed spinal neoplasms; 5 of 6 neurofibromas and 2 ependymomas enhanced. In the 216 patients with abnormalities thought not to be neoplastic, the enhancement rate was 11%; most of the enhancing lesions were vascular malformations. There were very few examples of inflammatory disease, acute trauma or stroke among our patients.

Immunosuppressive action of Qinghaosu

Qinghaosu, isolated and purified from the Chinese herb, Artemisia annua Linn, and identified as a sesquiterpene with a peroxide bridge and lactone structure, is a highly potent and non-toxic new antimalaria drug. This paper reports the immunosuppressive action of its water soluble derivative (hemisuccinate NA, QHS). The remarkable suppression by QHS of the in vitro 3HTdR incorporation by mitogen-stimulated mouse spleen cells and human peripheral lymphocytes, as well as the spontaneous incorporation by mouse thymocytes and blood cells from some leukemia patients is presented and its characteristics are described. The in vivo effect as shown by quantitative PFC is studied and the difference between the present in vitro and in vivo effects is investigated. The possible mechanism of inhibition and discrepancy in effects are discussed.