Follow-up of 53 Alzheimer patients with the MODA (Milan Overall Dementia Assessment)

Fifty-three patients affected by Alzheimer's disease entered a longitudinal survey aimed at studying which factors influence the rate of progression, assessed by means of the Milan Overall Dementia Assessment (MODA). The second examination was carried out, on average, after 16 months from the first assessment. Only age proved to influence the decline rate, which was faster in elders

Exploiting the capacity of 1mm PMMA step-index polymer optical fibers

Three different techniques are discussed that are currently under investigation at Siemens Corporate Technology – Information and Communications in order to exploit the bandwidth capacity of 1 mm PMMA Step-Index Polymer Optical Fiber (SI-POF). By using Adaptive Multitone Modulation (AMTM) a record result of 540 Mb/s transmission over 100 m of SI-POF is achieved

Degradation studies of InAs/GaAs QD lasers grown on Si

Lowering the threshold gain of InAs quantum dot lasers grown on Silicon, significantly extends device lifetime. Measurements on degraded devices show increased optical mode loss is responsible for degradation and a consequent shortening of lasing wavelength

Degradation of III–V Quantum Dot Lasers Grown Directly on Silicon Substrates

Initial age-related degradation mechanisms for InAs quantum dot lasers grown on silicon substrates emitting at 1.3 μm are investigated. The rate of degradation is observed to increase for devices operated at higher carrier densities and is therefore dependent on gain requirement or cavity length. While carrier localization in quantum dots minimizes degradation, an increase in the number of defects in the early stages of aging can increase the internal optical-loss that can initiate rapid degradation of laser performance due to the rise in threshold carrier density. Population of the two-dimensional states is considered the major factor for determining the rate of degradation, which can be significant for lasers requiring high threshold carrier densities. This is demonstrated by operating lasers of different cavity lengths with a constant current and measuring the change in threshold current at regular intervals. A segmented-contact device, which can be used to measure the modal absorption and also operate as a laser, is used to determine how the internal optical-loss changes in the early stages of degradation. Structures grown on silicon show an increase in internal optical loss, whereas the same structure grown on GaAs shows no signs of increase in internal optical loss when operated under the same conditions

Neuropsychiatric symptoms in 921 elderly subjects with dementia: a comparison between vascular and neurodegenerative types.

Objective:  i) to describe the neuropsychiatric profile of elderly subjects with dementia by comparing vascular (VaD) and degenerative dementias, i.e. dementia with Lewy bodies (DLB) and Alzheimer’s disease (AD); ii) to assess whether the severity and type of dementia are associated with clinically relevant neuropsychiatric symptoms (CR‐NPS). Method:  One hundred and thirty‐one out‐patients with VaD, 100 with DLB and 690 with AD were studied. NPS were evaluated by the neuropsychiatric inventory (NPI). Results:  Vascular dementia had lower total and domain‐specific NPI scores and a lower frequency of CR‐NPS than AD and DLB, for which frequency of CR‐NPS increased significantly with disease severity, particularly in AD. Logistic regression analysis showed that a higher CDR score and a diagnosis of degenerative dementia were independently associated with CR‐NPS. Conclusion:  Vascular dementia is associated less with CR‐NPS than AD and DLB. Frequency of CR‐NPS increases with disease severity in AD and, to a lesser extent, in DLB

Increasing Maximum Gain in InAs Quantum Dot Lasers on GaAs and Si

InAs quantum-dot (QD) lasers emitting at 1300nm with nominally undoped and modulated p-type doping are studied. Modal-gain measurements indicate a higher gain can be achieved from the ground-state for a given Fermi-level separation with p-doping and a reduced temperature-dependence of threshold current for short-cavity lasers

Development of a psychiatric disorder linked to cerebellar lesions

Cerebellar dysfunction plays a critical role in neurodevelopmental disorders with long-term behavioral and neuropsychiatric symptoms. A 43-year-old woman with a cerebellum arteriovenous malformation and history of behavioral dysregulation since childhood is described. After the rupture of the cerebellar malformation in adulthood, her behavior morphed into specific psychiatric symptoms and cognitive deficits occurred. The neuropsychological assessment evidenced impaired performance in attention, visuospatial, memory, and language domains. Moreover, psychiatric assessment indicated a borderline personality disorder. Brain MRI examination detected macroscopic abnormalities in the cerebellar posterior lobules VI, VIIa (Crus I), and IX, and in the posterior area of the vermis, regions usually involved in cognitive and emotional processing. The described patient suffered from cognitive and behavioral symptoms that are part of the cerebellar cognitive affective syndrome. This case supports the hypothesis of a cerebellar role in personality disorders emphasizing the importance of also examining the cerebellum in the presence of behavioral disturbances in children and adults