A new Zr/Hf separation system was developed with a novel unsymmetrical dialkylphosphinic acid extractant (
n
-octyl)(2,4,4'-trimethylpentyl)phosphinic acid (INET-1). It selectively extracts Hf over ...Zr, and shows much better Zr/Hf separation efficiency than organophosphorous acid Cyanex 272. The Zr and Hf extraction reactions at acidities of < 2 mol/L H
2
SO
4
and > 5.5 mol/L H
2
SO
4
are revealed, respectively. An organic phase with 10 mmol/L INET-1 can load > 290 mg/L of Hf at 1 mol/L H
2
SO
4
. Acidic H
2
SO
4
solutions with concentration of 3.0–4.5 mol/L is a good Zr scrubbing agent.
Purpose
Previous studies have indicated disrupted functional connectivity in multiple brain regions and resting-state networks in episodic migraine, but it is unclear how brain network property is ...disrupted in chronic migraine.
Methods
Using resting-state functional magnetic resonance imaging and voxel-wise functional connectivity density analysis, we examined the large-scale functional connectivity pattern over the whole brain in 17 patients with chronic migraine without medication overuse compared to 35 healthy controls. The associations between functional connectivity density and clinical variables were also explored.
Results
Compared with controls, chronic migraine patients showed decreased local and distant functional connectivity density in the dorsolateral and medial prefrontal cortexes and precuneus and increased local and distant functional connectivity density in the hippocampal complex. The patients also presented increased local functional connectivity density in the orbital frontal gyrus and cerebellum and increased distant functional connectivity density in the temporal pole. Moreover, local functional connectivity density in several brain regions, such as the left superior temporal gyrus and dorsal anterior cingulate cortex, was found to be correlated with headache frequency or pain intensity.
Conclusion
Chronic migraine is associated with functional connectivity alterations in regions involved in multisensory integration, affective and cognitive processing, and pain modulation. Both local and distant functional connectivity density are complementary biomarkers for investigating the neural mechanism of this disorder. Some local functional connectivity density alterations may be useful for assessing the disease burden of chronic migraine.
A coal fire is one of the most serious disasters in coal mining. To improve the efficiency of an inert gas for extinguishing the fire, the adsorption behavior of coal in CO
2
/N
2
mixed gas was ...investigated in this study. Proximate analysis, ultimate analysis, solid-state
13
C nuclear magnetic resonance spectroscopy (NMR), X-ray photoelectron spectroscopy (XPS), and molecular dynamics (MD) were applied to analyze and establish the bituminous coal molecular model. The adsorption behavior of bituminous coal in mixed gas mixtures with different proportions was studied using the bituminous coal model and Materials Studio (MS) software. A self-built coal adsorption experimental system was used for experiments. The adsorption of bituminous coal to CO
2
is stronger than that to N
2
, and there is a competitive adsorption relationship between them. The amount of CO
2
adsorbed by the coal gradually increases as the CO
2
partial pressure rises, consistent with the Langmuir model. With an increase in CO
2
pressure, the total adsorption capacity, which is divided into the rapid increase stage, slow growth stage, and stable stage, also increases. The coal adsorbs 0.5050 cm
3
/g, 0.7455 cm
3
/g, 0.9450 cm
3
/g, 1.0715 cm
3
/g, and 1.2000 cm
3
/g for pure N
2
, 2%, 5%, 7%, and 10% CO
2
, respectively, in the experiment. The results of the simulation and experiment show the same trend, which means that the injection of a small amount of CO
2
into pure N
2
will greatly improve the gas adsorption volume of the coal, demonstrating that it is feasible to improve the ability of the coal to absorb mixed gases by changing the gas concentration and consequently to increase the efficiency of inert gas for fire extinguishing and suppression.
Zr/Hf separation has always been a great challenge. Although the methyl isobutyl ketone (MIBK)-thiocyanic acid (HSCN) extraction system selectively extracts Hf over Zr and can realize Zr/Hf ...separation, it has the following disadvantages: it has a strong smell; it is easy to burn; and there is large loss of extractant during extraction due to the low boiling point (115.7 °C), low flashing point (13 °C), and high solubility of MIBK in water (1.7 % at 25 °C). In this study, Zr/Hf separation performance by MIBK homologues — of which one side of C = O is isopentyl, isohexyl, n-pentyl, n-hexyl or n-heptyl, while the other side are all methyl — were studied and compared with MIBK. Effects of HSCN pre-extraction, HCl concentration, NH4SCN concentration on Zr, Hf extraction and separation performance were investigated. Relationships between methyl alkyl ketone structure and their Zr/Hf separation performance were revealed. A new Zr/Hf separation system MNPK (methyl n-pentyl ketone)-HSCN was found. MNPK has a higher boiling point (151 °C), a higher flashing point (47 °C) and a lower solubility in water (0.43 % at 20 °C) than MIBK. Compared to MIBK, it is safer, more friendly operation environments and less extractant loss during extraction. MNPK has as fast extraction kinetics as MIBK. It also has good anti-emulsification performance. Its maximum βHf/Zr can reach to 12.61. The loaded Zr and Hf in MNPK have very similar stripping behaviors with those loaded in MIBK by HCl and H2SO4 solutions, respectively. MNPK is the most possible candidate to replace MIBK from HSCN media in Zr/Hf separation industry.
Background
Prior MRI studies on vestibular migraine (VM) have revealed abnormalities in static regional intrinsic brain activity (iBA) and dynamic functional connectivity between brain regions or ...networks. However, the temporal variation and concordance of regional iBA measures remain to be explored.
Methods
57 VM patients during the interictal period were compared to 88 healthy controls (HC) in this resting-state functional magnetic resonance imaging (fMRI) study. The dynamics and concordance of regional iBA indices, including amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo), were examined by utilizing sliding time-window analysis. Partial correlation analyses were performed between clinical parameters and resting-state fMRI indices in brain areas showing significant group differences.
Results
The VM group showed increased ALFF and ReHo dynamics, as well as increased temporal concordance between ALFF and ReHo in the bilateral paracentral lobule and supplementary motor area relative to the HC group. We also found decreased ReHo dynamics in the right temporal pole, and decreased ALFF dynamics in the right cerebellum posterior lobe, bilateral angular gyrus and middle occipital gyrus (MOG) in the VM group compared with the HC group. Moreover, a positive correlation was observed between ALFF dynamics in the left MOG and vertigo disease duration across all VM patients.
Conclusion
Temporal dynamics and concordance of regional iBA indices were altered in the motor cortex, cerebellum, occipital and temporoparietal cortex, which may contribute to disrupted multisensory processing and vestibular control in patients with VM. ALFF dynamics in the left MOG may be useful biomarker for evaluating vertigo burden in this disorder.
Neuroimaging studies have implicated abnormal brain microstructure in episodic migraine (EM), but whether the pattern is altered during migraine chronification is not well known. Fifty-six patients ...with migraine without aura, including 39 EM patients and 17 chronic migraine (CM) patients, and 35 healthy controls (HCs) were enrolled. Voxel-based morphometry analysis was performed to assess gray matter (GM) volume differences among groups and their association with clinical feature was examined. Compared with the HC group, both migraine groups showed increased GM volume in the periaqueductal grey matter (PAG) and decreased GM volume in the anterior cingulate cortex (ACC). The left hippocampus/parahippocampal gyrus (PHG) volume of the HC group was smaller than that of the EM group, but was larger than that of the CM group. For the dorsolateral prefrontal cortex (dlPFC), the EM group showed the smallest GM volume while the CM group had the largest volume. Higher headache frequency was associated with greater GM volume in the PAG and dlPFC, but was associated with smaller GM volume in the ACC and hippocampus/PHG across all patients. GM volume changes in regions involved in pain generation and control are potential neural mechanism underlying migraine, and are associated with migraine types and headache frequency.
Background: Hypothesis-driven functional connectivity (FC) analyses have revealed abnormal functional interaction of regions or networks involved in pain processing in episodic migraine patients. We ...aimed to investigate the resting-state FC patterns in episodic migraine by combining data-driven voxel-wise degree centrality (DC) calculation and seed-based FC analysis. Methods: Thirty-nine patients suffering from episodic migraine without aura and 35 healthy controls underwent clinical assessment and functional MRI. DC was analyzed in a voxel-wise way and compared between groups, and FC of regions with DC differences were further examined using a seed-based approach. Results: Compared with control group, the migraine group showed increased and decreased DC in the right posterior insula and left crus I, respectively. Seed-based FC analyses revealed that migraine patients demonstrated increased right posterior insula connections with the postcentral gyrus, supplementary motor area/paracentral lobule, fusiform gyrus and temporal pole. The left crus I showed decreased FC with regions of the default mode network (DMN), including the medial prefrontal cortex (mPFC), angular gyrus, medial and lateral temporal cortex in patients with migraine. Furthermore, pain intensity positively correlated with DC in the right amygdala/parahippocampal gyrus, and migraine frequency negatively correlated with FC between the left curs I and mPFC. Conclusion: Patients with episodic migraine without aura have increased FC with the right posterior insula and decreased FC within the DMN, which may underlie disturbed sensory integration and cognitive processing of pain. The left crus I-mPFC connectivity may be a useful biomarker for assessing migraine frequency.
Headache is a common accompanying symptom of cerebrovascular diseases. The most common patterns of headache for different cerebrovascular disorders, aetiology and pathogenesis and diagnostic workup ...are reviewed with emphasis on distinguishing characteristics. It will be a clinical guide for physicians who treat patients with headache or cerebral vascular disease.
New human immunodeficiency virus type 1 (HIV-1) diagnoses are increasing rapidly in Hebei. The aim of this study presents the most extensive HIV-1 molecular epidemiology investigation in Hebei ...province in China thus far. We have carried out the most extensive systematic cross-sectional study based on newly diagnosed HIV-1 positive individuals in 2013, and characterized the molecular epidemiology of HIV-1 based on full length gag-partial pol gene sequences in the whole of Hebei. Nine HIV-1 genotypes based on full length gag-partial pol gene sequence were identified among 610 newly diagnosed naïve individuals. The four main genotypes were circulating recombinant form (CRF)01_AE (53.4%), CRF07_BC (23.4%), subtype B (15.9%), and unique recombinant forms URFs (4.9%). Within 1 year, three new genotypes (subtype A1, CRF55_01B, CRF65_cpx), unknown before in Hebei, were first found among men who have sex with men (MSM). All nine genotypes were identified in the sexually contracted HIV-1 population. Among 30 URFs, six recombinant patterns were revealed, including CRF01_AE/BC (40.0%), CRF01_AE/B (23.3%), B/C (16.7%), CRF01_AE/C (13.3%), CRF01_AE/B/A2 (3.3%) and CRF01_AE/BC/A2 (3.3%), plus two potential CRFs. This study elucidated the complicated characteristics of HIV-1 molecular epidemiology in a low HIV-1 prevalence northern province of China and revealed the high level of HIV-1 genetic diversity. All nine HIV-1 genotypes circulating in Hebei have spread out of their initial risk groups into the general population through sexual contact, especially through MSM. This highlights the urgency of HIV prevention and control in China.
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