All-dielectric scale invariant waveguide.

Total internal reflection (TIR) governs the guiding mechanisms of almost all dielectric waveguides and therefore constrains most of the light in the material with the highest refractive index. The few options available to access the properties of lower-index materials include designs that are either lossy, periodic, exhibit limited optical bandwidth or are restricted to subwavelength modal volumes. Here, we propose and demonstrate a guiding mechanism that leverages symmetry in multilayer dielectric waveguides as well as evanescent fields to strongly confine light in low-index materials. The proposed waveguide structures exhibit unusual light properties, such as uniform field distribution with a non-Gaussian spatial profile and scale invariance of the optical mode. This guiding mechanism is general and can be further extended to various optical structures, employed for different polarizations, and in different spectral regions. Therefore, our results can have huge implications for integrated photonics and related technologies.

Telerehabilitation following fast-track total knee arthroplasty is effective and safe: a randomized controlled trial with the ReHub® platform.

PURPOSE: After a total knee arthroplasty (TKA), ensuring rehabilitation is continued at home is essential for a successful recovery. The aim of this randomized clinical trial (NCT04155957) was to demonstrate the safety and efficacy of an interactive telerehabilitation system (ReHub®) to guide and provide feedback during exercise in the postoperative period of a fast-track TKA program. METHODS: Fifty-two patients who underwent TKA were randomized to intervention (N = 26) or control (N = 26). Upon discharge, they followed a 4-week plan of 5 daily exercises and up to 10 physiotherapy home visits. The intervention group performed exercises with ReHub® autonomously, control did not use any auxiliary device. Data were collected 1) on the day of discharge, 2) after 2 weeks and 3) after 4 weeks. RESULTS: Telerehabilitation patients showed higher adherence to exercise (p = 0.002) and greater quadriceps strength (p = 0.028). No significant differences between groups were found in other outcomes. Only 1 adverse event was linked to ReHub®. Patients gave the platform high System Usability Scale scores (83/100). CONCLUSION: Interactive telerehabilitation with ReHub® during a post-TKA exercise program is effective, safe, and well-received by patients. It provides real-time performance feedback and ensures communication. Quadriceps strength and adherence to the exercise plan are improved with ReHub®.IMPLICATIONS FOR REHABILITATIONTelerehabilitation platforms can be introduced into fast-track total knee arthroplasty protocols to monitor home-based exercise programmes without compromising efficacy and safety.Telerehabilitation and remote patient monitoring contribute to obtaining high levels of adherence to exercise plans, which is a current challenge faced by rehabilitation professionals.Real-time biofeedback on exercise performance facilitates correct exercise performance and motivates the patient.This technology allows professionals to monitor and adjust the patient's therapy remotely and avoid unnecessary travel.

Non-rigid alignment pipeline applied to human gait signals acquired with optical motion capture systems and inertial sensors.

An accurate gait characterization is fundamental for diagnosis and treatment in both clinical and sportive fields. Although several devices allow such measurements, the performance comparison between the acquired signals may be a challenging task. A novel pipeline for the accurate non-rigid alignment of gait signals is proposed. In this paper, the measurements of Inertial Measurement Units (IMU) and Optical Motion Capture Systems (OMCAP) are aligned using a modified version of the Dynamic Time Warping (DTW) algorithm. The differences between the two acquisitions are evaluated using both global (RMSE, Correlation Coefficient (CC)) and local (Statistical Parametric Mapping (SPM)) metrics. The method is applied to a data-set obtained measuring the gait of ten healthy subjects walking on a treadmill at three different gait paces. Results show a global bias between the signal acquisition of 0.05°. Regarding the global metrics, a mean RMSE value of 2.65° (0.73°) and an average CC value of 0.99 (0.01) were obtained. The SPM profile shows, in each gait cycle phase, the percentage of cases when two curves are statistically identical and reaches an average of 48% (22%).

[IMPACT OF AGING IN PSYCHIATRY]. / Impacto del envejecimiento en la psiquiatría.

The changes associated with aging influence the clinical presentation and treatment approach of psychiatric illness. Several psychiatric disorders are common in old age as depression or set of diseases with cognitive impairment requiring geriatric knowledge. In many countries psychiatry of the elderly are called psychogeriatric. Regardless of the name objective of this article is to convey that the psychiatrist who treats patients over 65 years with multiple disorders, with frailty social problems and polypharmacy should have some tools in addition to the thorough understanding of psychiatric illness itself. Teamwork, meet physiological changes of aging and how these affect the response to drugs, atypical presentation of illness and keep in mind the importance of psychosocial and environmental issues both in presentation and in addressing and monitoring of disease.

Renal creatinine handling in very old patients with chronic renal disease.

UNLABELLED: Renal creatinine handling is basically the result of its glomerular filtration and proximal tubular secretion. However, creatinine reabsorption has been documented in certain conditions, such as premature babies, newborns, and healthy elderly people. Additionally, it is known that there is an increase in the proportion of secreted creatinine in chronic renal disease. In this paper, we report our studies on the characteristic reabsorption pattern of creatinine in the elderly with chronic renal disease. MATERIAL & METHOD: We studied twenty-seven volunteers with chronic kidney disease, eleven of whom were young and the rest were very old (age > 75 years old). We measured creatinine clearance without (Ccr) and with cimetidine (CcrWC) and Ccr/CcrWC ratio from each volunteer, in timed urine samples. Then, Ccr, CcrWC, and Ccr/CcrWC ratio were compared between young and very old people in two chronic kidney disease subgroups: stages II-III and stages IV-V. Statistical analysis was performed applying a non-parametric test (Wilcoxon). RESULTS: We observed a tendency towards a lower Ccr/CcrWC ratio in the very old stage II-III group compared with the young one: 1 (0.96-1.26) (very old) vs 1.3 (1.1-1.5) (young), P = 0.09, on the contrary, there was no significant difference in Ccr/CcrWC ratio between very old and young person with stage IV-V CKD: 1.66 (1.41-2.21) (young) vs 1.77 (1.1-2.7) (young), P = NS. CONCLUSION: Creatinine secretion pattern in very old patients with advanced chronic renal disease is similar to that observed in young ones with similar level of CKD.

Renal physiology in elderly persons with severe immobility syndrome.

OBJECTIVE: The immobility syndrome (IS) is a common condition in the elderly and consists of a reduction in the capacity to perform daily activities because of motor function deterioration. This syndrome leads to characteristic structural and physiological changes in the body, but renal physiology studies have not been conducted on this population. For this reason, we decided to study prospectively changes in renal function in these individuals. MATERIAL AND METHODS: We enrolled into this study 17 volunteers over 64 years of age, all of whom lived in the same nursing home. The patients were divided into two groups: nine healthy mobile persons and eight others who suffered from severe IS. Exclusion criteria were the presence of any disease or use of any drug that could induce water and electrolytes alteration. Blood and urine samples were drawn to measure sodium, potassium, creatinine, urea, calcium, phosphorus, magnesium, and uric acid in order to obtain their fractional excretion. Plasma osmolality and vasopressin were also measured. Total body water and lean body mass were obtained by bioelectrical impedance analysis. Statistical analysis was performed applying Student's t-test (P = 0.01) and Pearson's correlation test. RESULTS: A significant difference in body water composition was found between the groups. Thus in the IS group plasma sodium level was slightly lower and total water content was significantly higher than in the mobile subjects: 140 +/- 5 vs. 143 +/- 1 mmol/l (P = 0.01); 61 +/- 8% vs. 50 +/- 10% (P < 0.001), respectively. Despite these differences, plasma osmolality and vasopressin values were within the normal range in both groups. However, there was a good positive correlation between these two variables in the mobile group only: R 0.9 (mobile) vs. R -0.2 (immobile). We found no significant difference in plasma creatinine or fractional excretion of sodium, potassium, calcium, phosphorus, magnesium, urea, and uric acid between the groups. CONCLUSION: Total body water content was significantly higher in the elderly who suffered from severe immobility syndrome than in healthy mobile elderly. In contrast with the mobile group, for which there was a good positive correlation between plasma osmolality and plasma vasopressin, for individuals with IS there was no correlation between plasma osmolality and plasma vasopressin.

[Seasonal variations in 25-hydroxyvitamin D in young and elderly and populations in Buenos Aires City]. / Variaciones estacionales de 25-hidroxivitamina D en Jóvenes y ancianos de la ciudad de Buenos Aires.

The purpose of this study was to evaluate the level of hypovitaminosis D in elderly and young outpatients populations of the City of Buenos Aires, and to establish its impact on bone remodeling. A total of 83 elderly and 76 young patients aged 71.9 +/- 8.1 and 29.8 +/- 6.6 years respectively, were evaluated by measuring 25-hydroxyvitamin D, 25 (OH)D, middle-molecular parathyroid hormone, and biochemical measurements of bone and mineral metabolism markers. In winter, insufficient values of 25(OH)D were observed both in elderly and young populations: 14.2% of the elderly and 15.9% of young people showed deficient values of 25(OH)D. In summer, an increase in the two groups was observed. Parathyroid hormone levels were higher in the elderly group. Secondary hyperparathyroidism was reported only in the aged group (28.1% in winter, and 20.5% in summer). The increased levels of parathyroid hormone and the presence of secondary hyperparathyroidism in the elderly would be conditioned by this deficiency and other additional factors such as age, renal insufficiency and nutrition degree. In winter, there was an increase in the bone remodeling markers, with higher values in the elderly group. In the City of Buenos Aires decreased levels of 25(OH)D were seen both in young and elderly individuals, with seasonal variations. Sanitary policies are necessary to prevent hypovitaminosis D, because this condition predisposes for osteoporosis.

Enfermedad de Alzheimer / Alzheimer's disease

La enfermedad de Alzheimer (EA) es una enfermedad neuro-cognitiva prevalente en los ancianos (40 por ciento en mayores de 80 años) caracterizada por la pérdida progresiva de capacidades cognitivas. Se cuenta actualmente con tratamientos moderadamente eficaces para detener o mejorar el ritmo de declinación (inhibidores de la colinesterasa), buenos tratamientos de los síntomas no demenciales y adecuadas instituciones de soporte comunitario en casi todo el mundo. Está claro que los sujetos mejor educados y estimulados a lo largo de sus vidas tienen menos riesgo de desarrollar EA. El conocimiento en el desarrollo de la enfermedad es avanzado (generación del beta-amiloide) pero no suficiente para cambiar la prevalencia o el curso de la enfermedad. Este artículo actualiza la epidemiología, la fisiopatogenia, las formas clínicas, la sistemática de estudio y los tratamientos de la enfermedad de Alzheimer

Enfermedad de Alzheimer / Alzheimers disease

La enfermedad de Alzheimer (EA) es una enfermedad neuro-cognitiva prevalente en los ancianos (40 por ciento en mayores de 80 años) caracterizada por la pérdida progresiva de capacidades cognitivas. Se cuenta actualmente con tratamientos moderadamente eficaces para detener o mejorar el ritmo de declinación (inhibidores de la colinesterasa), buenos tratamientos de los síntomas no demenciales y adecuadas instituciones de soporte comunitario en casi todo el mundo. Está claro que los sujetos mejor educados y estimulados a lo largo de sus vidas tienen menos riesgo de desarrollar EA. El conocimiento en el desarrollo de la enfermedad es avanzado (generación del beta-amiloide) pero no suficiente para cambiar la prevalencia o el curso de la enfermedad. Este artículo actualiza la epidemiología, la fisiopatogenia, las formas clínicas, la sistemática de estudio y los tratamientos de la enfermedad de Alzheimer

Variaciones estacionales de 25-hidroxivitamina D en jovenes y ancianos de la ciudad de Buenos Aires / Seasonal variations in 25-hydroxyvitamin D in young and elderly populations in Buenos Aires City

La hipovitaminosis D es un fenómeno observado con frecuencia en personas mayores y en centros urbanos. Los objetivos de este estudio fueron determinar los niveles circulantes de 25-hidroxi-vita-mina D, 25(OH)D, en pacientes ambulatorios ancianos y jóvenes de la ciudad de Buenos Aires y establecer el impacto de valores descendidos de Vitamina D en la remodelación ósea. Se evaluaron 83 ancianos y 76 jóve-nes de 71.9±8.1 y 29.8±6.6 años respectivamente, mediante la medición de 25(OH)D, parathormona medio-molecular y de marcadores del metabolismo óseo y mineral. En invierno se comprobaron valores de 25 (OH) D en grado de insuficiencia en ambos grupos y un 14.2% de ancianos y 15.9% de jóvenes con valores menores de 10 ng/ml. En verano se observó un incremento de la 25(OH)D en toda la población, sin embargo los niveles circulantes de Vitamina D no superaron los 40 ng/ml, en ambos grupos. Los niveles plasmáticos de parathormona fueron más elevados en ancianos que en jóvenes y en esa subpoblación se observó la presencia de hiperparatiroidismo secundario. La elevación de parathormona está condicionada por la deficiencia de vitamina D y otros factores adicionales como la edad, la insuficiencia renal y el grado de nutrición de la población. La remodelación ósea presentó variaciones estacionales: se incrementó en invierno en ambos grupos. En la ciudad de Buenos Aires se han observado niveles descendidos de Vitamina D en jóvenes y mayores, durantetodo el año. Se deberán evaluar las políticas sanitarias apropiadas destinadas a corregir esta deficiencia, lacual predispone a la osteoporosis.

Variaciones estacionales de 25-hidroxivitamina D en Jóvenes y ancianos de la ciudad de Buenos Aires. / [Seasonal variations in 25-hydroxyvitamin D in young and elderly and populations in Buenos Aires City]

The purpose of this study was to evaluate the level of hypovitaminosis D in elderly and young outpatients populations of the City of Buenos Aires, and to establish its impact on bone remodeling. A total of 83 elderly and 76 young patients aged 71.9 +/- 8.1 and 29.8 +/- 6.6 years respectively, were evaluated by measuring 25-hydroxyvitamin D, 25 (OH)D, middle-molecular parathyroid hormone, and biochemical measurements of bone and mineral metabolism markers. In winter, insufficient values of 25(OH)D were observed both in elderly and young populations: 14.2

of the elderly and 15.9

of young people showed deficient values of 25(OH)D. In summer, an increase in the two groups was observed. Parathyroid hormone levels were higher in the elderly group. Secondary hyperparathyroidism was reported only in the aged group (28.1

in winter, and 20.5

in summer). The increased levels of parathyroid hormone and the presence of secondary hyperparathyroidism in the elderly would be conditioned by this deficiency and other additional factors such as age, renal insufficiency and nutrition degree. In winter, there was an increase in the bone remodeling markers, with higher values in the elderly group. In the City of Buenos Aires decreased levels of 25(OH)D were seen both in young and elderly individuals, with seasonal variations. Sanitary policies are necessary to prevent hypovitaminosis D, because this condition predisposes for osteoporosis.

Variaciones estacionales de 25-hidroxivitamina D en jovenes y ancianos de la ciudad de Buenos Aires / Seasonal variations in 25-hydroxyvitamin D in young and elderly populations in Buenos Aires City

La hipovitaminosis D es un fenómeno observado con frecuencia en personas mayores y en centros urbanos. Los objetivos de este estudio fueron determinar los niveles circulantes de 25-hidroxi-vita-mina D, 25(OH)D, en pacientes ambulatorios ancianos y jóvenes de la ciudad de Buenos Aires y establecer el impacto de valores descendidos de Vitamina D en la remodelación ósea. Se evaluaron 83 ancianos y 76 jóve-nes de 71.9±8.1 y 29.8±6.6 años respectivamente, mediante la medición de 25(OH)D, parathormona medio-molecular y de marcadores del metabolismo óseo y mineral. En invierno se comprobaron valores de 25 (OH) D en grado de insuficiencia en ambos grupos y un 14.2% de ancianos y 15.9% de jóvenes con valores menores de 10 ng/ml. En verano se observó un incremento de la 25(OH)D en toda la población, sin embargo los niveles circulantes de Vitamina D no superaron los 40 ng/ml, en ambos grupos. Los niveles plasmáticos de parathormona fueron más elevados en ancianos que en jóvenes y en esa subpoblación se observó la presencia de hiperparatiroidismo secundario. La elevación de parathormona está condicionada por la deficiencia de vitamina D y otros factores adicionales como la edad, la insuficiencia renal y el grado de nutrición de la población. La remodelación ósea presentó variaciones estacionales: se incrementó en invierno en ambos grupos. En la ciudad de Buenos Aires se han observado niveles descendidos de Vitamina D en jóvenes y mayores, durantetodo el año. Se deberán evaluar las políticas sanitarias apropiadas destinadas a corregir esta deficiencia, lacual predispone a la osteoporosis.(AU)