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1.
Nanotechnology ; 33(17)2022 Feb 01.
Article in English | MEDLINE | ID: mdl-35026738

ABSTRACT

On Cu(111) surface and in interaction with a single hexa-tert-butylphenylbenzene molecule-gear, the rotation of a graphene nanodisk was studied using the large-scale atomic/molecular massively parallel simulator molecular dynamics simulator. To ensure a transmission of rotation to the molecule-gear, the graphene nanodisk is functionalized on its circumference bytert-butylphenyl chemical groups. The rotational motion can be categorized underdriving, driving and overdriving regimes calculating the locking coefficient of this mechanical machinery as a function of external torque applied to the nanodisk. The rotational friction with the surface of both the phononic and electronic contributions is investigated. For small size graphene nanodisks, the phononic friction is the main contribution. Electronic friction dominates for the larger disks putting constrains on the experimental way of achieving the transfer of rotation from a graphene nanodisk to a single molecule-gear.

2.
Nanotechnology ; 24(39): 395702, 2013 Oct 04.
Article in English | MEDLINE | ID: mdl-24008430

ABSTRACT

We study circular nanomechanical graphene resonators by means of continuum elasticity theory, treating them as membranes. We derive dynamic equations for the flexural mode amplitudes. Due to the geometrical nonlinearity the mode dynamics can be modeled by coupled Duffing equations. By solving the Airy stress problem we obtain analytic expressions for the eigenfrequencies and nonlinear coefficients as functions of the radius, suspension height, initial tension, back-gate voltage and elastic constants, which we compare with finite element simulations. Using perturbation theory, we show that it is necessary to include the effects of the non-uniform stress distribution for finite deflections. This correctly reproduces the spectrum and frequency tuning of the resonator, including frequency crossings.

3.
Neuropsychiatr ; 24(2): 67-87, 2010.
Article in German | MEDLINE | ID: mdl-20605003

ABSTRACT

The Austrian Alzheimer Society developed evidence-based guidelines based on a systematic literature search and criteria-guided assessment with subsequent transparent determination of grades of clinical recommendation. The authors evaluated currently available therapeutic approaches for the most common forms of dementia and focused on diagnosis and pharmacological intervention, taking into consideration the situation in Austria. The purpose of these guidelines is the rational and cost-effective use of diagnostic and therapeutic measures in dementing illnesses. Users are physicians and all other providers of care for patients with dementia in Austria.


Subject(s)
Dementia/diagnosis , Dementia/drug therapy , Evidence-Based Medicine , Nootropic Agents/therapeutic use , Aged , Aged, 80 and over , Amino Acids/adverse effects , Amino Acids/therapeutic use , Antipsychotic Agents/adverse effects , Antipsychotic Agents/therapeutic use , Cholinesterase Inhibitors/adverse effects , Cholinesterase Inhibitors/therapeutic use , Cognition Disorders/diagnosis , Cognition Disorders/drug therapy , Cross-Sectional Studies , Dementia/epidemiology , Dementia/etiology , Drug Therapy, Combination , Female , Ginkgo biloba , Humans , Incidence , Life Style , Long-Term Care , Male , Medication Adherence , Memantine/adverse effects , Memantine/therapeutic use , Middle Aged , Plant Extracts/adverse effects , Plant Extracts/therapeutic use , Population Dynamics , Psychotropic Drugs/adverse effects , Psychotropic Drugs/therapeutic use , Randomized Controlled Trials as Topic
4.
Wien Med Wochenschr ; 152(3-4): 107-12, 2002.
Article in German | MEDLINE | ID: mdl-11925770

ABSTRACT

Beside the loss of the memory capacity, non-cognitive disturbances occur up to 70%-90% in patients suffering from Alzheimer's disease due to pathological changes in the brain. Delusion, hallucination and changes of the circadian rhythm can appear in addition to the five kinds of disorder--agitation, aggressive behaviour, screaming, depression and constant hyperkinesia. The consequences of these changes in perception and behaviour constitute severe problems for the patient as well as for the main caregiver. The burden of caring often exceeds their energy and resources. Not only do many of those caregivers suffer themselves from exhaustion but also from feelings of guilt and depression. The therapeutic concept includes the involvement of the relatives through information, support, counselling and guidance as much as the investigation of the causes and interrelation of the problematic behaviour in each individual case and further involves the carer in creating a concept to deal in an optimal way with the patient.


Subject(s)
Adaptation, Psychological , Caregivers/psychology , Self-Help Groups , Aged , Behavior Therapy , Cost of Illness , Humans , Social Support
5.
Can Vet J ; 34(10): 584, 1993 Oct.
Article in English | MEDLINE | ID: mdl-17424300
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