Accelerating the laser-induced demagnetization of a ferromagnetic film by antiferromagnetic order in an adjacent layer

We study the ultrafast demagnetization of Ni/NiMn and Co/NiMn ferromagnetic/antiferromagnetic bilayer systems after excitation by a laser pulse. We probe the ferromagnetic order of Ni and Co using magnetic circular dichroism in time-resolved pump-probe resonant x-ray reflectivity. Tuning the sample temperature across the antiferromagnetic ordering temperature of the NiMn layer allows us to investigate effects induced by the magnetic order of the latter. The presence of antiferromagnetic order in NiMn speeds up the demagnetization of the ferromagnetic layer, which is attributed to bidirectional laser-induced superdiffusive spin currents between the ferromagnetic and the antiferromagnetic layer

Thermal- and Light-Induced Spin-Crossover Characteristics of a Functional Iron(II) Complex at Submonolayer Coverage on HOPG

Studies on the spin-state switching characteristics of surface-bound thin films of spin-crossover (SCO) complexes are of interest to harness the device utility of the SCO complexes. Molecule–substrate interactions govern the SCO of surface-bound films in direct contact with the underlying substrates. In this study, we elucidate the role of molecule–substrate interactions on the thermal- and light-induced spin-state switching characteristics of a functional SCO-complex—[Fe(H2B(pz)2)2COOC12H25-bipy] (pz = pyrazole, C12-bpy = dodecyl[2,2′-bipyridine]-5-carboxylate) deposited at a submonolayer coverage on a highly oriented pyrolytic graphite (HOPG) substrate. A spin-state coexistence of 42% low-spin (LS) and 58% high-spin (HS) is observed for the 0.4 ML deposit of the complex at 40 K, in contrast to the complete spin-state switching observed in the bulk and in SiOx-bound 10 nm thick films. Cooling the sample to 10 K results in a decrease of the LS fraction to 36%, attributed to soft-X-ray-induced excited spin-state trapping (SOXIESST). Illumination of the sample with a green light (λ = 520 nm) at 10 K caused the LS-to-HS switching of the remaining (36%) LS complexes, by a process termed light-induced excited spin-state trapping (LIESST). The mixed spin-state in the submonolayer coverage of [Fe(H2B(pz)2)2COOC12H25-bipy] highlights the role of molecule–HOPG substrate interactions in tuning the thermal SCO characteristics of the complex. The 100% HS state obtained after light irradiation indicates the occurrence of efficient on-surface light-induced spin switching, encouraging the development of light-addressable molecular devices based on SCO complexes

Comparison of the Effect of Exercise Therapy with Transcutaneous Electrical Nerve Stimulation on Improvement of Pain and Function in Patients with Patellofemoral Pain Syndrome

ABSTRACT: Introduction & Objective: One of the most common disorders of the knee joint in adult is patellofemoral pain syndrome. Sometimes it becomes chronic and causes activity limitation. This study aimed to compare the efficacy of exercise therapy with Transcutaneous Electrical Nerve Stimulation on improvement of pain intensity, knee function, muscle atrophy and range of knee flexion. Materials & Methods: This double-blind, randomized clinical trial was carried out in Zahedan Razmejo-Moghadam Physiotherapy Clinic, in 2007. Thirty-two patients with patellofemoral pain syndrome were recruited through simple non-probability sampling. Subjects were randomly assigned to one of the equal groups, exercise therapy (including hip, knee, and leg muscles strengthening and stretching exercises) or electrical stimulation group. Before and after intervention, we assessed pain through Visual Analog Scale (VAS) (ordinal), function (ordinal) with Knee Injury and Osteoarthritis Outcome Score (KOOS), thigh circumference with tape measure (centimeter) and range of knee flexion with goniometer (degree). A 10 session treatment program, three sessions per week and one hour per session was performed for both groups. Independent t-test or Mann-Whitney U and paired t-test or Wilcoxon were used for comparison between the pretreatment and post treatment results between groups and within groups, in SPSS software, respectively. Results: The mean total score of knee function increased from 100.53±19.25 to 130.87±18.25 in the electrical stimulation group and from 107.67±22.69 to 131.47±15.11 in the exercise therapy group (p=0.001). The mean score of knee function subscales including symptoms, pain, functional limitation, recreational activity, and life style improved in both groups (p<0.05). The pain score and range of knee flexion improved in both groups (p<0.05). After treatment, range of knee flexion significantly increased in the exercise group compared with the electrical stimulation one (p=0.008). Conclusion: Both of the exercise therapy and transcutaneous electrical nerve stimulation are effective in treatment of patellofemoral pain syndrome. However, exercise therapy is more effective increasing in the range of knee flexion

Cross-cultural Adaptation and Validation of the Persian Version of Voice Disability Coping Questionnaire (P-VDCQ): Introducing a New Instrument

Objectives: Coping is one of the important concepts in psychology, which is pertinent to how persons with illness manage the stress of that condition. Voice Disability Coping Questionnaire (VDCQ) is an assessment tool for quantifying coping strategies in those with voice disability. The purpose of the present study was to investigate reliability and validity of the Persian version of VDCQ (P-VDCQ). Method: Translation procedure was performed according to the World Health Organization guidelines, and then 138 persons (88 persons with voice disorders and 50 controls) completed the questionnaire. Psychometric properties of the P-VDCQ were investigated. Results: There was a significant difference between the mean value of patients with dysphonia and that of the control group. The results of test-result reliability indicated that there is a high correlation between repeated administration of the questionnaire (intraclass correlation coefficient = 89.7). Also, a high Cronbach's alpha coefficient (α = 0.94) revealed a good internal consistency. Participants' scores in this instrument had a moderate correlation with their scores on Voice Activity Participation Profile�Persian version (r = 0.41, P < 0.001). Conclusion: The P-VDCQ is a reliable and a valid instrument that can be used to investigate coping strategies of patients with dysphonia in clinical settings and for research purposes. © 2018 The Voice Foundatio

Synthesis, Characterization, and Application of Partially Blocked Amine-Functionalized Magnetic Nanoparticles

In this study, a novel technique was introduced for selective surface modification of amine-functionalized magnetic nanoparticles. The method was based on alignment of magnetic nanoparticles in an external magnetic field, which resulted in formation of chain-like assemblies in diluted suspensions. The aligned chains were then modified on the surface via reaction of isocyanate species with the particle functionalities. Finally, after removal from the reactor medium, particles with segmented distribution of surface functionalities were achieved. We named these partially blocked amine-functionalized magnetic nanoparticles as “Saturn” nanoparticles. Application of the particles in fabrication of magnetic assemblies was successfully demonstrated. Using methylene diphenyl diisocyanate (MDI) as the bridging agent, structures in different forms such as chains and filaments were produced by the Saturn particles and compared with cross-linked structures of the unmodified amine-functionalized particles. It is expected that this novel nanoparticle with its unique structure will have great potential in assembly fabrication with a variety of applications in biomedical fields

Thermal and Light Induced Spin Crossover Characteristics of a Functional Iron II Complex at Submonolayer Coverage on HOPG

Studies on the spin state switching characteristics of surface bound thin films of spin crossover SCO complexes are of interest to harness the device utility of the SCO complexes. Molecule substrate interactions govern the SCO of surface bound films in direct contact with the underlying substrates. In this study, we elucidate the role of molecule substrate interactions on the thermal and light induced spin state switching characteristics of a functional SCO complex [Fe H2B pz 2 2COOC12H25 bipy] pz pyrazole, C12 bpy dodecyl[2,2 amp; 8242; bipyridine] 5 carboxylate deposited at a submonolayer coverage on a highly oriented pyrolytic graphite HOPG substrate. A spin state coexistence of 42 low spin LS and 58 high spin HS is observed for the 0.4 ML deposit of the complex at 40 K, in contrast to the complete spin state switching observed in the bulk and in SiOx bound 10 nm thick films. Cooling the sample to 10 K results in a decrease of the LS fraction to 36 , attributed to soft X ray induced excited spin state trapping SOXIESST . Illumination of the sample with a green light amp; 955; 520 nm at 10 K caused the LS to HS switching of the remaining 36 LS complexes, by a process termed light induced excited spin state trapping LIESST . The mixed spin state in the submonolayer coverage of [Fe H2B pz 2 2COOC12H25 bipy] highlights the role of molecule HOPG substrate interactions in tuning the thermal SCO characteristics of the complex. The 100 HS state obtained after light irradiation indicates the occurrence of efficient on surface light induced spin switching, encouraging the development of light addressable molecular devices based on SCO complexe