Strain-Driven Bidirectional Spin Orientation Control in Epitaxial High Entropy Oxide Films.

High entropy oxides (HEOs), based on the incorporation of multiple-principal cations into the crystal lattice, offer the possibility to explore previously inaccessible oxide compositions and unconventional properties. Here it is demonstrated that despite the chemical complexity of HEOs external stimuli, such as epitaxial strain, can selectively stabilize certain magneto-electronic states. Epitaxial (Co0.2 Cr0.2 Fe0.2 Mn0.2 Ni0.2 )3 O4 -HEO thin films are grown in three different strain states: tensile, compressive, and relaxed. A unique coexistence of rocksalt and spinel-HEO phases, which are fully coherent with no detectable chemical segregation, is revealed by transmission electron microscopy. This dual-phase coexistence appears as a universal phenomenon in (Co0.2 Cr0.2 Fe0.2 Mn0.2 Ni0.2 )3 O4 epitaxial films. Prominent changes in the magnetic anisotropy and domain structure highlight the strain-induced bidirectional control of magnetic properties in HEOs. When the films are relaxed, their magnetization behavior is isotropic, similar to that of bulk materials. However, under tensile strain, the hardness of the out-of-plane (OOP) axis increases significantly. On the other hand, compressive straining results in an easy OOP magnetization and a maze-like magnetic domain structure, indicating the perpendicular magnetic anisotropy. Generally, this study emphasizes the adaptability of the high entropy design strategy, which, when combined with coherent strain engineering, opens additional prospects for fine-tuning properties in oxides.

Formation of Solid Solutions and Physicochemical Properties of the High-Entropy Ln1-xSrx(Co,Cr,Fe,Mn,Ni)O3-δ (Ln = La, Pr, Nd, Sm or Gd) Perovskites.

Phase composition, crystal structure, and selected physicochemical properties of the high entropy Ln(Co,Cr,Fe,Mn,Ni)O3-δ (Ln = La, Pr, Gd, Nd, Sm) perovskites, as well as the possibility of Sr doping in Ln1-xSrx(Co,Cr,Fe,Mn,Ni)O3-δ series, are reported is this work. With the use of the Pechini method, all undoped compositions are successfully synthesized. The samples exhibit distorted, orthorhombic or rhombohedral crystal structure, and a linear correlation is observed between the ionic radius of Ln and the value of the quasi-cubic perovskite lattice constant. The oxides show moderate thermal expansion, with a lack of visible contribution from the chemical expansion effect. Temperature-dependent values of the total electrical conductivity are reported, and the observed behavior appears distinctive from that of non-high entropy transition metal-based perovskites, beyond the expectations based on the rule-of-mixtures. In terms of formation of solid solutions in Sr-doped Ln1-xSrx(Co,Cr,Fe,Mn,Ni)O3-δ materials, the results indicate a strong influence of the Ln radius, and while for La-based series the Sr solubility limit is at the level of xmax = 0.3, for the smaller Pr it is equal to just 0.1. In the case of Nd-, Sm- and Gd-based materials, even for the xSr = 0.1, the formation of secondary phases is observed on the SEM + EDS images.

Gait pattern in patients with peripheral artery disease.

BACKGROUND: The aim of the present paper is to assess the gait pattern of patients with Peripheral Artery Disease (PAD). A more specific aim is to compare the gait pattern of PAD patients before and after the appearance of intermittent claudication symptoms. METHODS: The study involved 34 PAD patients with a claudication distance ≥200 m and 20 participants without PAD, who formed the control group. The gait pattern of PAD patients was assessed twice: before the appearance of intermittent claudication symptoms (pain-free conditions) and after the appearance of intermittent claudication symptoms (pain conditions). RESULTS: Compared to the control group, PAD patients presented a statistically significant decrease in step length both during pain-free conditions (52.6 ± 12.5 vs. 72.8 ± 18.5 cm, p = 0.008) and in pain conditions (53.3 ± 13.3 vs. 72.8 ± 18.5 cm, p = 0.006). As for the remaining spatiotemporal parameters, there were no differences observed between the patient group and the controls. Intermittent claudication symptom induced by the walking test on the treadmill did not bring about any new abnormalities in the gait pattern or intensify the existing abnormalities of the gait. CONCLUSIONS: PAD patients have a tendency to shorten their step length regardless of the presence of intermittent claudication.

The Impact of Walking Exercises and Resistance Training upon the Walking Distance in Patients with Chronic Lower Limb Ischaemia.

Objective. The objective of this paper is to compare the impact of supervised walking and resistance training upon the walking distance in PAD patients. Materials and Methods. The examination involved 50 PAD patients at the 2nd stage of the disease according to Fontaine's scale. The participants were randomly allocated to two groups: one exercising on the treadmill (n = 24) and one performing resistance exercises of lower limbs (n = 26). Results. The 12-week program of supervised rehabilitation led to a significant increase in the intermittent claudication distance measured both on the treadmill and during the 6-minute walking test. The group training on the treadmill showed a statistically significant increase of the initial claudication distance (ICD) and the absolute claudication distance (ACD) measured on the treadmill, as well as of ICD and the total walking distance (TWD) measured during the 6-minute walking test. Within the group performing resistance exercises, a statistically significant improvement was observed in the case of parameters measured on the treadmill: ICD and ACD. Conclusions. The supervised rehabilitation program, in the form of both walking and resistance exercises, contributes to the increase in the intermittent claudication distance. The results obtained in both groups were similar.

Neurological and neurophysiological examinations of workers exposed to arsenic levels exceeding hygiene standards.

OBJECTIVES: The assessment of the neurotoxic effect of arsenic (As) and its inorganic compounds is still the subject of interest due to a growing As application in a large array of technologies and the need to constantly verify the principles of prevention and technological parameters. The aim of this study was to determine the status of the nervous system (NS) in workers exposed to As at concentrations exceeding hygiene standards (Threshold Limit Values (TLV) - 10 µg/m(3), Biological Exposure Index (BEI) - 35 µg/l) and to analyze the relationship between the NS functional state, species of As in urine and As levels in the workplace air. MATERIAL AND METHODS: The study group comprised 21 men (mean age: 47.43±7.59) employed in a copper smelting factory (mean duration of employment: 22.29±11.09). The control group comprised 16 men, matched by age and work shifts. Arsenic levels in the workplace air (As-A) ranged from 0.7 to 92.3 µg/m(3); (M = 25.18±28.83). The concentration of total arsenic in urine (As(tot)-U) ranged from 17.35 to 434.68 µg/l (M = 86.82±86.6). RESULTS: Syndrome of peripheral nervous system (PNS) was manifested by extremity fatigue (28.6%), extremity pain (33.3%) and paresthesia in the lower extremities (33.3%), as well as by neuropathy-type mini-symptoms (23.8%). Electroneurographic (ENeG) tests of peroneal nerves showed significantly decreased response amplitude with normal values of motor conduction velocity (MCV). Stimulation of sural nerves revealed a significantly slowed sensory conduction velocity (SCV) and decreased sensory potential amplitude. Neurophysiological parameters and the results of biological and environmental monitoring showed a relationship between As(tot), As(III) (trivalent arsenic), the sum of iAs (As(III)+As(V) (pentavalent arsenic))+MMA (monomethylarsonic acid) concentration in urine and As levels in the air. CONCLUSIONS: The results of the study demonstrate that occupational exposure to inorganic arsenic levels exceeding hygiene standards (TLV, BEI) generates disorders typical of peripheral neuropathy.

Comparison of neurobehavioral and biochemical effects in rats exposed to dusts from copper smelter plant at different locations.

Mixed exposure to metals (including arsenic and lead) associated with the neurological and respiratory effects constitute one of the major health problems of copper smelting. Chemical composition of the dust, and the expected health effect of inhalation can be very diverse at different parts of the smelter plant. The aims of this study were to compare lung responses and behavioral effects in female Wistar rats after instillation of dust collected from different production processes at the same smelter department. Dusts collected at two different locations of furnace hall were sifted through 25-µm-mesh sieve. Obtained dust fractions, P-25(I) collected near stove, rich in heavy metals and arsenic, and P-25(II) collected near anode residue storage site, rich in aluminium, were instilled to rats. At 1, 7 and 30 days after dusts instillation, lung injury and inflammation were measured by analyzing sings of lung permeability in the bronchoalveolar lavage fluid (BALF), cell differentiation in BALF sediment and lung morphology. The behavioral studies were done 30 days after exposure. Results of biochemical tests showed a strong pro-inflammatory effect of P-25(I) fractions. Mostly characteristic effects after instillation of P-25(I) samples were 10× increased protein leakages in BALF. Both P-25(I) and P-25(II) fractions caused a reduction of Clara-cell 16 protein concentration (CC16) in BALF and activation of serum butyrylcholinesterase (BChE) at all time points. The morphological studies after exposure to P-25(I) fractions showed multi-focal infiltrations in the alveoli. The behavioral results, especially P-25(II) group rats (in open filed, passive avoidance and hot plate tests), indicated adverse effects in the nervous system, which may be related to changes in the dopaminergic and cholinergic pathway. The symptoms were noted in the form of persistent neurobehavioral changes which might be associated with the content of neurotoxic metals. e.g. Al, Mn and/or As. Decrease of CC16 concentration that occurred immediately after instillation of both dust samples, point out impaired anti-inflammatory potential, resulted in early harmful effect not only to the respiratory tract but also to the whole body, including the nervous system.

Effects of occupational exposure to arsenic on the nervous system: clinical and neurophysiological studies.

OBJECTIVES: A number of metals, especially heavy metals, exhibit neurotoxic properties. Neurological and neurophysiological studies indicate that the functions of the central (CNS) and peripheral nervous system (PNS) may be impaired under conditions of exposure to arsenic (As). The aim of the present study was to assess the effects of inorganic arsenic on the central and peripheral nervous system. MATERIALS AND METHODS: The study covered a group of 21 male workers (mean age: 41.9 yr; SD: 7.6; range: 31-55 yr) employed in a copper smelting factory. Their employment duration ranged from 5 to 33 years (mean: 18.1 yr; SD: 7.8). Arsenic concentrations in workplace air amounted to 0.01003 mg/m3 on average (SD: 0.00866). Urine arsenic concentrations ranged from 3.48 to 23.63 µg/l (mean: 11.91 µg/l; SD: 9.5). The control group consisted of 16 males non-occupationally exposed to As, matched for gender, age and work shift pattern. The evaluation of neurological effects was based on the findings of neurological examination, electroencephalography (EEG), visual evoked potentials (VEPs) and electroneurography (ENeG). RESULTS: Clinical symptoms, such as sleeplessness or sleepiness, irritability, headache, painful spasms in extremity muscles, extremity paresthesia and pain, and muscular fatigue prevailed among functional disorders of the nervous system in workers chronically exposed to As. Neurological examination did not reveal any organic lesions in the CNS or PNS. In EEG records classified as abnormal, generalized changes were most common. VEP examinations revealed abnormalities in evoked response latency. Stimulation of the motor fibers of the peroneal and medial nerves resulted in a decreased amplitude of the motor potential. Stimulation of the sensory fibers of medial nerves brought about a decreased amplitude of the sensory potential and a lower conduction velocity of the sural nerves. CONCLUSION: The findings of the study indicate that exposure to As concentrations within the threshold limit values (TLV) can induce subclinical effects on the nervous system, especially subclinical neuropathy.

[The effect of combined exposure to chemical and physical factors on the nervous system during aluminum production: a preliminary finding]. / Skutki zdrowotne w ukladzie nerwowym tacznego narazenia na czynniki chemiczne i fizyczne podczas produkcji aluminium. Doniesienie wstepne.

BACKGROUND: The authors present the results of medical examinations of workers employed in an aluminum electrolysis plant with occupational exposure to aluminum dust, polycyclic aromatic hydrocarbons, and magnetic field. METHODS AND MATERIALS: The study covered a selected group of 39 male workers (mean age, 44,9; SD = 7.5 years; range 29-55 years) involved in the aluminum production. Their employment duration ranged between 5 and 32 years (mean, 17.8; SD = 6.7 years). Urine aluminum concentrations in workers ranged from 8.9 to 70.2 microg/g creatinine (mean, 31.72; SD = 18.3 microg/g creatinine). Urine 1-hydroxypyrene concentrations recorded in workers ranged from 0.67 to 10.09 microg/g creatinine (mean, 3.42; SD = 2.1 microg/g creatinine). The control group consisted of 39 men matched by gender, age and work shifts. RESULTS: Clinical symptoms, such as headache (46.2%), increased emotional irritability (66.7%), concentration difficulty (25.6%), insomnia (30.8%), hypersomnia (15.4%), and mood lability (10.3%) predominated among functional disorders of the nervous system in workers chronically exposed to chemical and physical factors. The objective neurological examinations did not reveal organic lesions in the central or peripheral nervous system. In EEG recordings, classified as abnormal, paroxysmal changes were most common (20.5%). CONCLUSIONS: The authors emphasized great difficulty in evaluating the combined effects of toxic and physical factors exerted on the nervous system.

[Neurologic and neurophysiologic examinations of workers occupationally exposed to aluminium]. / Neurologiczna i neurofizjologiczna ocena pracowników zawodowo narazonych na glin.

BACKGROUND: Studies conducted to assess aluminum (Al)-induced toxicity to humans and environment. It has been implicated that Al is involved in the etiology of Alzheimer's disease and other neurodegenerative disorders, though this is controversial. The aim of the present study was to assess Al effects on the nervous system functions in workers chronically exposed to this metal. METHODS AND MATERIALS: The study covered a selected group of 67 male workers (mean age, 38.7 +/- 10.3 years; range 23-55 years) involved in aluminum production. Their employment duration ranged between 2 and 34 years (mean, 14.6 +/- 8.9 years). Aluminum oxide (Al2O3) concentrations varied from 0.2 to 1.95 mg/m3 (arithmetic mean, 0.40 mg/m3, geometric mean, 0.35 mg/m3, SD = 0.29). Urine aluminum concentrations found in smelters ranged from 8.5 to 93.0microg/l (mean, 42.9 +/- 20.5 microg/l). The control group consisted of 57 men non-occupationally exposed to Al matched by gender, age and work shifts. RESULTS: Clinically, headache (41,8%), increased emotional irritability (56,7%), concentration difficulty (22,4%), insomnia (22,4%) and mood lability (14,9%) predominated among functional disorders of the nervous system in workers chronically exposed to Al. The objective neurological examinations did not reveal organic lesions in the central or peripheral nervous system. In EEG classified as abnormal, generalized and paroxysmal changes were most common. Examinations of visual evoked potentials (VEP) revealed abnormalities, primarily in the latency of the response evoked. CONCLUSIONS: The results of this study suggest that exposure to Al2O3 at concentrations within MAC values induces subclinical effect in the nervous system.

Neurological and respiratory symptoms in shipyard welders exposed to manganese.

OBJECTIVE: The nervous system is the major target of the toxic effect of manganese (Mn) and its compounds in welding fumes. In humans, inhalation is the most frequent route of Mn access, therefore, the respiratory tract and lungs are usually involved in the process of translocation of inhaled noxius agent by blood to the brain. This study was performed to assess whether it is possible to use neurophysiological tests for the detection of early effects of exposure to low Mn concentrations. It is also known that irritating welding fumes affect distal bronchioles of nonciliated, epithelial Clara cells, which secret anti-inflammatory and immunossupresive Clara cell protein (CC16) into the respiratory tract. The examination of usefulness of CC16 as early pulmonary biomarker for neurophysiological abnormal results of welding fumes exposure was performed. MATERIALS AND METHODS: The study group comprised 59 welders employed at different workposts in a shipyard, matched for age and smoking habits with the control group composed of 23 mechanicians and electricians not exposed to welding fumes. Subjective neurological symptops (CNS), visual evoked potentials (VEP) and electroencephalography (EEG) were examined in welders and the relationships between Mn concentrations in the air, blood and urine as well as between cummulative exposure index (CEI) (Mn mg/m3 x years of exposure) were investigated. Effects of exposure were expressed in the form of biomarkers of the body burden, and CC16 as early pulmonary biomarker in welding exposure was examined by sensitive latex-immunoassay. RESULTS: Abnormal results of VEP and EEG and the lowest CC16 levels were found in the youngest welders exposed to welding fumes. Those changes were related to the highest Mn airborne levels (xg > 0.3 mg/m3) and high blood Mn concentrations (approximately 14.0 microg/dL). The highest values of correlation coefficients were found only in welders characterized by abnormal neurophysiological results, VEP (r = 0.83) and VEP and VEP+EEG (r = 0.82). The multiple linear regression analysis from all analyzed subgroups, indicated that those with only abnormal neurophysiological tests, VEP and EEG, showed the highest values of partial correlation. It also revealed partial correlation cofficiants between Mn in the air, CEI (Mn mg/m3 x years) and CC16, Mn-B and Mn-U in VEP and VEP+EEG groups. It was found that the highest partial correlations were between the magnitude of exposure--Mn mg/m3, CEI and Mn-B concentration (R2 = 0.72, R2 = 0.66) as well as between CC16 pulmonary biomarker effects and Mn-B concentration (R2 = 0.51). CONCLUSIONS: The subclinical effects revealed in neurological endpoints and abnormal results of neurophysiological tests, VEP and EEG, confirmed that those sensitive tests could be used for the detection of early effect of exposure to low manganese concentration. Inhibition of Clara cell protein secretion in younger welders not adapted to the Mn environment suppresses anti-inflammatory effect in the respiratory tract and probably enhances the absorption and thus the incidence of subclinical neurotoxic symptoms related to airborne Mn and Mn-B levels.

Effects of occupational exposure to aluminum on nervous system: clinical and electroencephalographic findings.

OBJECTIVES: The aim of the present study was to assess the effects of aluminum (Al) on the nervous system functions in workers chronically exposed to Al. MATERIALS AND METHODS: The study covered a selected group of 67 male workers (mean age, 38.7 SD 10.3 years; range 23-55 years) involved in the Al production. Their employment duration ranged between 2 and 34 years (mean, 14.6 SD 8.9 years). Aluminum oxide (Al203) concentrations varied from 0.13 to 1.95 mg/m3 (arithmetic mean, 0.40 mg/3, geometric mean, 0.35 mg/m3 SD 0.29). Urine Al concentrations found in smelters ranged from 8.5 to 93.0 microg/l (mean, 42.9 SD 20.5 microg/l). The control group consisted of 57 men non-occupationally exposed to Al, matched by gender, age and work shifts. RESULTS: Clinically, headache (41.8%), increased emotional irritability (56.7%), concentration difficulty (22.4%), insomnia (22.4%) and mood lability (14.9%) predominated among functional disorders of the nervous system in workers chronically exposed to Al. Objective neurological examinations did not reveal organic lesions in the central or peripheral nervous system. In the EEGs classified as abnormal, generalized and paroxysmal changes were most common. CONCLUSIONS: The results of this study suggest that exposure to Al203 at concentrations below MAC values induces subclinical effect in the nervous system.