Bulk Oxygen Diffusion and Surface Exchange Limitations in La2−xSrxNi1-yFeyO4+δ

The oxygen permeation flux through dense La1.2Sr0.8Ni0.9Fe0.1O4

Synthesis, Crystal Structure, and Properties of NdNi0.5Mn0.5O3−

The crystal structure and properties of NdNi0.5Mn0.5O3

Crystal structure, oxygen non-stoichiometry and conductivity of Nd1-xAxMn0.5Fe0.5O3-δ (A=Ca, Sr, Ba)

This work was financially supported by RFBR (project No. 16-53-45010 IND_а)

Sentinel headache as a warning symptom of ischemic stroke

Background: There are no previous controlled studies of sentinel headache in ischemic stroke. The purpose of the present study was to evaluate the presence of such headache, its characteristics and possible risk factors as compared to a simultaneous control group. Methods: Eligible patients (n = 550) had first-ever acute ischemic stroke with presence of new infarction on magnetic resonance imaging with diffusion-weighted imaging (n = 469) or on computed tomography (n = 81). As a control group we studied in parallel patients (n = 192) who were admitted to the emergency room without acute neurological deficits or serious neurological or somatic disorders. Consecutive patients with stroke and a simultaneous control group were extensively interviewed soon after admission using validated neurologist conducted semi-structured interview forms. Based on our previous study of sentinel headache in transient ischemic attacks we defined sentinel headache as a new type of headache or a previous kind of headache with altered characteristics (severe intensity, increased frequency, absence of effect of drugs) within seven days before stroke. Results: Among 550 patients with stroke 94 patients (17.1%) had headache during seven days before stroke and 12 (6.2%) controls (p < 0.001; OR 3.9; 95% CI 1.7-5.8). Totally 81 patients (14.7%) had sentinel headache within the last week before stroke and one control. Attacks of arrythmia during seven days before stroke were significantly associated with sentinel headache (p = 0.04, OR 2.3; 95% CI 1.1-4.8). Conclusions: A new type of headache and a previous kind of headache with altered characteristics during one week before stroke are significantly more prevalent than in controls. These headaches represent sentinel headaches. Sudden onset of such headaches should alarm about stroke. © 2020 The Author(s)

Optical, Magnetic and Magneto-Transport Properties of Nd 1-xAxMn0.5Fe0.5O3-δ (A=Ca, Sr, Ba; x=0, 0.25)

The effect of A-site doping by alkaline earth metals (A = Ca, Sr and Ba) on optical, magnetic, and electrical properties of Nd1-xAxMn0.5Fe0·5O3-δ (x = 0, 0.25) has been investigated. The UV–vis absorption spectra show that the A-site doping decreases the absorption. Two values of optical band-gap energy (Eg) can be estimated for each studied sample: the higher Eg value is associated with the charge transfer involving iron cations and the lower Eg value – with the charge transfer via manganese cations. Partial substitution of neodymium by alkaline earth metals decreases the Néel temperature (TN) and induces significant irreversibility between the zero-field cooled (ZFC) and field-cooled (FC) data below TN. The field-dependent magnetization at 3 K indicates antiferromagnetic ordering with a spin canting. Temperature dependencies of resistivity demonstrate the change from metallic to semiconductor-type conduction (with increasing temperature) at T = Tp &lt; TN. The Tp temperature significantly decreases with doping. The introduction of alkaline earth metals in Nd1-xAxMn0.5Fe0·5O3-δ noticeably reduces the resistivity in the semiconducting region. The small polaron hopping (SPH) mechanism of conduction is suggested at T &gt; TN. Within the range of Tp &lt; T &lt; TN, the resistivity data are interpreted by the variable range hopping (VRH) mechanism. A significant value of magnetoresistance (∼44%) is observed only for Nd0.75Sr0·25Mn0·5Fe0·5O3-δ at 120 K. © 2020 Elsevier B.V.A. S. acknowledges, the financial support provided by the Department of Science and Technology (DST), Government of India (Indo-Russian project (INT/RUS/RFBR/P-239); A.R.G and V.A.C. acknowledge the financial support from Indo-Russian project (RFBR grant No 16-53-45010); and A.H. acknowledges financial support obtained from the Government of the Russian Federation by Act 211 agreement 02.A03.21.0006

Association of vascular endothelial growth factor B (VEGFВ) gene polymorphisms with intracranial aneurysms

Intracranial aneurysm (IA) is a complex disease resulting in subarachnoid hemorrhage (SAH) due to a rupture. The average worldwide prevalence of this disease is about 2–5 %, with 50 % of them ending in death or neurological disorders of varying severity, with a high probability of recurrence of hemorrhage during the frst half of the year after rupture. Subarachnoid hemorrhage is annually registered in at least 18 thousand people in Russia. Associations of polymorphic variants rs594942 and rs11603042 of the VEGFB gene in intracranial aneurysm development in the Volga-Ural region of the Russian Federation with the presence of the symptom complex of undifferentiated connective tissue dysplasia (uDST) and arterial hypertension (AH) were investigated. The C* allele rs594942 and rs11603042 of the VEGFB gene is a marker of an increased risk of IA as a whole (p = 0.025; χ2 = 5.052; OR = 1.32) in women as a whole (p = 0.001; χ2 = 10.124; OR = 1.70) and in comorbid state with uDCT (p = 0.002; χ2 = 9.501; OR = 2.34) and AG (p = 0.006; χ2 = 7.385; OR = 2.109). We found that the genotype *C*C of locus rs594942 of the VEGFB gene is a marker of an increased risk of intracranial aneurysm in general (p = 0.017; χ2 = 5.702; OR = 1.49) and among women in general (p = 0.0005; χ2 = 12.078; OR = 2.25) and with the symptomatic complex uCTD (p = 0.007; χ2 = 7.173; OR = 2.67) and AH (p = 0.010; χ2 = 6.471; OR = 2.51). We have obtained new results on the role of polymorphic variants of the VEGFB gene in the formation of intracranial aneurysm, taking into account the presence of the symptom complex uDCT and AH among the residents of the Volga-Ural region of Russia. A burdened comorbid background and the presence of undifferentiated connective tissue dysplasia and arterial hypertension can contribute to an increased risk of intracranial aneurysm, as evidenced by the results of our study

Diagnostic Criteria for Acute Headache Attributed to Ischemic Stroke and for Sentinel Headache Before Ischemic Stroke

Background: Defining the relationship between a headache and stroke is essential. The current diagnostic criteria of the ICHD-3 for acute headache attributed to ischemic stroke are based primarily on the opinion of experts rather than on published clinical evidence based on extensive case-control studies in patients with first-ever stroke. Diagnostic criteria for sentinel headache before ischemic stroke do not exist. The present study aimed to develop explicit diagnostic criteria for headache attributed to ischemic stroke and for sentinel headache. Methods: This prospective case-control study included 550 patients (mean age 63.1, 54% males) with first-ever ischemic stroke and 192 control patients (mean age 58.7, 36% males) admitted to the emergency room without any acute neurological deficits or severe disorders. Standardized semi-structured interview forms were used to evaluate past and present headaches during face-to-face interviews by a neurologist on admission to the emergency room in both groups of patients. All headaches were diagnosed according to the ICHD-3. We tabulated the onset of different headaches before a first-ever ischemic stroke and at the time of onset of stroke. We divided them into three groups: a new type of headache, the previous headache with altered characteristics and previous unaltered headaches. The same was done for headaches in control patients within one week before admission to the hospital and at the time of entry. These data were used to create and test diagnostic criteria for acute headache attributed to stroke and sentinel headache. Results: Our previous studies showed that headache at onset of ischemic stroke was present in 82 (14.9%) of 550 patients, and 81 (14.7%) patients had sentinel headache within the last week before a stroke. Only 60% of the headaches at stroke onset fulfilled the diagnostic criteria of ICHD-3. Therefore, we proposed alternative criteria with a sensitivity of 100% and specificity of 97%. Besides, we developed diagnostic criteria for sentinel headache for the first time with a specificity of 98% and a sensitivity of 100%. Conclusions: We suggest alternative diagnostic criteria for acute headache attributed to ischemic stroke and new diagnostic criteria for sentinel headache with high sensitivity and specificity. © 2022, The Author(s)