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Patients with compromised respiratory function frequently require mechanical ventilation to survive. Unfortunately, non-uniform ventilation of injured lungs generates complex mechanical forces that lead to ventilator induced lung injury (VILI). Although investigators have developed lung-on-a-chip systems to simulate normal respiration, modeling the complex mechanics of VILI as well as the subsequent recovery phase is a challenge. Here we present a novel humanized in vitro ventilator-on-a-chip (VOC) model of the lung microenvironment that simulates the different types of injurious forces generated in the lung during mechanical ventilation. We used transepithelial/endothelial electrical impedance measurements to investigate how individual and simultaneous application of mechanical forces alters real-time changes in barrier integrity during and after injury. We find that compressive stress (i.e. barotrauma) does not significantly alter barrier integrity while over-distention (20% cyclic radial strain, volutrauma) results in decreased barrier integrity that quickly recovers upon removal of mechanical stress. Conversely, surface tension forces generated during airway reopening (atelectrauma), result in a rapid loss of barrier integrity with a delayed recovery relative to volutrauma. Simultaneous application of cyclic stretching (volutrauma) and airway reopening (atelectrauma), indicates that the surface tension forces associated with reopening fluid-occluded lung regions are the primary driver of barrier disruption. Thus, our novel VOC system can monitor the effects of different types of injurious forces on barrier disruption and recovery in real-time and can be used to interogate the biomechanical mechanisms of VILI. [ABSTRACT FROM AUTHOR]

Adequate nutrition is very essential, especially for the Armed Forces, to buildup their nutritional reserves while deriving maximum benefits of training/peak performances in operational situations by keeping their morale high. The present study reviews/examines the adequacy of the existing ration scales of the Armed Forces personnel stationed under different terrain conditions of the country/recruits at various training centres. Food samples were collected from different strategic locations during different seasons of the year and analysed for their nutrient composition like proximal constituents, vitamins A, E, B1, B2, C, and dietary fibre. Based on the data generated, the daily nutrients/energy consumption by the soldiers/recruits, were calculated separately both for personnel in plains and at high altitudes. Soldiers in plains, on an average consumed protein 124.2 ± 13.0 g, fat 98.8 ± 29.6 g and energy 3632±317 kcal/person/day, while their counterparts at high altitudes consumed protein 120.4 ± 11.2 g, fat 120.1 ± 31.1 g, and energy 3906 ± 423 kcal/person/day. The study clearly indicate that the present ration scales for the Service personnel, both in plains and at high altitudes (9000 ft to 15000 ft) is adequate wrt their nutrient density. It is however suggested to ensure adequate supply of good quality fresh vegetables, fruits, and meat, which inturn would not only help to keep the morale of the soldiers, high and cheerful, especially at high altitudes, but will also enable adequate micronutrient availability. The fibre levels in the diets of these soldiers have also been found to be well within the limits (20 -35 g/ person/ day) recommended for optimal health. [ABSTRACT FROM AUTHOR]