Vapour pressure deficit modulates hydraulic function and structure of tropical rainforests under nonlimiting soil water supply.

Atmospheric conditions are expected to become warmer and drier in the future, but little is known about how evaporative demand influences forest structure and function independently from soil moisture availability, and how fast-response variables (such as canopy water potential and stomatal conductance) may mediate longer-term changes in forest structure and function in response to climate change. We used two tropical rainforest sites with different temperatures and vapour pressure deficits (VPD), but nonlimiting soil water supply, to assess the impact of evaporative demand on ecophysiological function and forest structure. Common species between sites allowed us to test the extent to which species composition, relative abundance and intraspecific variability contributed to site-level differences. The highest VPD site had lower midday canopy water potentials, canopy conductance (gc ), annual transpiration, forest stature, and biomass, while the transpiration rate was less sensitive to changes in VPD; it also had different height-diameter allometry (accounting for 51% of the difference in biomass between sites) and higher plot-level wood density. Our findings suggest that increases in VPD, even in the absence of soil water limitation, influence fast-response variables, such as canopy water potentials and gc , potentially leading to longer-term changes in forest stature resulting in reductions in biomass.

Two-Photon Microperimetry: A Media Opacity-Independent Retinal Function Assay.

Purpose: Compare results obtained using infrared two-photon microperimetry (2PM-IR) with conventional visual function tests in healthy subjects of varying ages with and without simulated media opacities. Methods: Subjects from two separate cohort studies completed cone contrast threshold (CCT) testing, conventional microperimetry, visible light microperimetry from a novel device (2PM-Vis), and infrared two-photon microperimetry. The first cohort study, which consisted of six healthy volunteers (23 to 29 years of age), evaluated the effects of simulated media opacities on visual performance testing. Subjects underwent testing on four visual function devices nine separate times under the following conditions: no filter, red filter, green filter, blue filter, light brown filter, dark brown filter, polarized black filter (0° rotation), and polarized black filter (90° rotation). Subjects subsequently performed 2PM-IR and 2PM-Vis testing without a filter in the mydriatic state. The second cohort study evaluated the effect of age on visual test performance in 42 healthy subjects split between two groups (ages 20-40 years and 60-80 years). Results: Retinal sensitivity measured by 2PM-IR demonstrated lower variability than all other devices relying on visible spectrum stimuli. Retinal sensitivity decreased proportionally with the transmittance of light through each filter. CCT scores and retinal sensitivity decreased with age in all testing modalities. Visible spectrum testing modalities demonstrated larger test result differences between young and old patient cohorts; this difference was inversely proportional to the wavelength of the visual function test. Conclusions: 2PM-IR mitigates media opacities that may mask small differences in retinal sensitivity when tested with conventional visual function testing devices. Translational Relevance: Conventional visual function tests that emit visible light may not detect differences in retinal function during the early stages of age-related diseases due to the confounding effects of cataracts. Infrared light, which has greater transmittance through ocular tissue, may reliably quantify retinal sensitivity and thereby detect degenerative changes early on.

Rapid Airway Narrowing Associated with Hodgkin's Lymphoma, a Case Report.

Hodgkin's lymphoma is a neoplastic proliferation of Reed Sternberg cells and inflammatory cells within the lymphatic system. Common symptoms associated with Hodgkin's Lymphoma include pronounced lymphadenopathy, fever, polynuclear leukocytosis, and anemia.1,2 This case study presents a unique case where an adult patient with nodular sclerosing Hodgkin's lymphoma (NSHL) presents with rapidly progressing dyspnea due to tracheal airway narrowing. CT results showed pathological lymph nodes in bilateral cervical stations, subclavian images and within the mediastinum, concerning for lymphoproliferative disease. Otolaryngology was consulted for a possible tracheostomy; however, an awake fiberoptic intubation was suggested and subsequently performed instead. This case demonstrates the importance of immediate intervention to prevent airway loss in an atypical presentation of NSHL. Topics: Nodular sclerosing Hodgkin's lymphoma, airway loss, intubation.

Advise and Assist: A Basic Medical Skills Course for Partner Forces.

BACKGROUND: Training partner forces in battlefield first-responder medical skills is an important component of US military advise-and-assist operations. We designed and executed a training curriculum focused on high-yield-based medical skills to prevent death on the battlefield for non-English speaking members of the Turkish, Azerbaijani, and Albanian militaries deployed to Afghanistan. METHODS: We designed a 2-hour training curriculum focusing on four basic medical skills: (1) assessment of scene safety; (2) limb tourniquet application; (3) wound bandaging; and (4) patient transportation via litter. Our combat medics delivered standardized training using both didactic and practicum components. Instructors made beforeand- after assessments of the proficiency of each participant for each skill in accordance with the Dreyfus model of skill acquisition. We also administered before-and-after, Likertscale- based surveys for training participants to report their self-assessed comfort level with each of the four skills. RESULTS: We delivered training to 187 participants over five classes. All 28 participants in the final teaching class completed the study. Instructors categorized each participant's skill level as novice before training for all four skills. After the training curriculum, all participants achieved a skill level consistent with advanced beginner for all four skills. Participants reported significant improvements in self-reported comfort levels for all taught procedures (ρ < .001 by Wilcoxon signed-rank test for all four skills). The largest reported increase in median comfort level was for tourniquet application: median pretraining comfort level, 4 (interquartile range [IQR], 0-6.25) versus 9.5 (IQR, 9-10) posttraining. CONCLUSION: Our curriculum resulted in significant improvements in instructor-assessed proficiency and self-reported comfort level for all four basic medical skills. Although our outcome measures have important limitations, this curriculum may be useful framework for future medics and physicians designing battlefield first-responder training curricula for members of foreign militaries.