Infrared light excites cells by changing their electrical capacitance

Optical stimulation has enabled important advances in the study of brain function and other biological processes, and holds promise for medical applications ranging from hearing restoration to cardiac pace making. In particular, pulsed laser stimulation using infrared wavelengths >1.5 μm has therapeutic potential based on its ability to directly stimulate nerves and muscles without any genetic or chemical pre-treatment. However, the mechanism of infrared stimulation has been a mystery, hindering its path to the clinic. Here we show that infrared light excites cells through a novel, highly general electrostatic mechanism. Infrared pulses are absorbed by water, producing a rapid local increase in temperature. This heating reversibly alters the electrical capacitance of the plasma membrane, depolarizing the target cell. This mechanism is fully reversible and requires only the most basic properties of cell membranes. Our findings underscore the generality of pulsed infrared stimulation and its medical potential

Audiologic monitoring of multi-drug resistant tuberculosis patients on aminoglycoside treatment with long term follow-up

<p>Abstract</p> <p>Background</p> <p>Multi-drug resistant tuberculosis has emerged as a significant problem with the resurfacing of tuberculosis and thus the need to use the second line drugs with the resultant increased incidence of adverse effects. We discuss the effect of second line aminoglycoside anti-tubercular drugs on the hearing status of MDR-TB patients.</p> <p>Methods</p> <p>Sixty four patients were put on second line aminoglycoside anti-TB drugs. These were divided into three groups: group I, 34 patients using amikacin, group II, 26 patients using kanamycin and group III, 4 patients using capreomycin.</p> <p>Results</p> <p>Of these, 18.75% of the patients developed sensorineural hearing loss involving higher frequencies while 6.25% had involvement of speech frequencies also. All patients were seen again approximately one year after aminoglycoside discontinuation and all hearing losses were permanent with no threshold improvement.</p> <p>Conclusion</p> <p>Aminoglycosides used in MDR-TB patients may result in irreversible hearing loss involving higher frequencies and can become a hearing handicap as speech frequencies are also involved in some of the patients thus underlining the need for regular audiologic evaluation in patients of MDR-TB during the treatment.</p

Widespread colonisation of Tanzanian catchments by introduced Oreochromis tilapia fishes: the legacy from decades of deliberate introduction

From the 1950s onwards, programmes to promote aquaculture and improve capture fisheries in East Africa have relied heavily on the promise held by introduced species. In Tanzania these introductions have been poorly documented. Here we report the findings of surveys of inland water bodies across Tanzania between 2011 and 2017 that clarify distributions of tilapiine cichlids of the genus Oreochromis. We identified Oreochromis from 123 sampling locations, including 14 taxa restricted to their native range and three species that have established populations beyond their native range. Of these three species, the only exotic species found was blue-spotted tilapia (Oreochromis leucostictus), while Nile tilapia (Oreochromis niloticus) and Singida tilapia (Oreochromis esculentus), which are both naturally found within the country of Tanzania, have been translocated beyond their native range. Using our records, we developed models of suitable habitat for the introduced species based on recent (1960–1990) and projected (2050, 2070) East African climate. These models indicated that presence of suitable habitat for these introduced species will persist and potentially expand across the region. The clarification of distributions provided here can help inform the monitoring and management of biodiversity, and inform policy related to the future role of introduced species in fisheries and aquaculture

Land use and cover changes in the Likangala catchment of the Lake Chilwa basin, Malawi: implications for managing a tropical wetland

This study analyses land use and cover changes in the Likangala River catchment of Lake Chilwa, Malawi, an endorheic tropical African lake. It also examines how land use-related physico-chemical and hydrological parameters in two affluent rivers of the lake affect the migratory and reproductive behaviour of Barbus paludinosus and B. trimaculatus, which are migratory, ecologically and economically important fish species. Land use analysis indicated increasing deforestation and conversion of agricultural land to homestead development. High soil losses of 100t ha–1 yr–1 were estimated in the upper reaches of the catchment. High rainfall kinetic energy and poor vegetation cover were major determinants of soil loss. Sediment yield was high (374t km–2 yr–1) in the more degraded catchment of the Likangala River, compared to 315t km–2 yr–1 in the less degraded Domasi River catchment. A situation analysis for the Likangala River catchment showed that a marked reduction in soil loss occurred when a combined 20% increase of contour ridging, maize yield and tree canopy was assumed. Multiple regression analysis indicated that sediment yield, river flow rate, electrical conductivity and total suspended solids are significant predictors of the migration dynamics and reproductive status of both Barbus species. Our results suggest that the most critical soil loss factor should form an integral part of soil conservation measures in the catchment and that appropriate management actions that reduce fishing pressure on breeding Barbus females in the affluent rivers should be formulated to ensure the success of spawning migrations of breeding females into these rivers. The study further demonstrates how a combination of land use modelling, community outreach, river water quality analysis and fish population dynamics analysis can be used to identify factors useful for managing and monitoring the catchments of small tropical lakes. Keywords: Barbus; deforestation; land use; soil erosion; spawning; sediment yield (Afr J Aqua Sci: 2003 28(2): 123-135

Hatchability of African Catfish Clarias gariepinus Eggs in Hapas and in Basins: a Diagnostic Study of Frequent Inhibition by Rainfall and Water Stagnation

To diagnose inhibition of egg hatchability by rainfall and water stagnation, some incubating eggs were protected against the physical impact of raindrops, some were subjected to various turbidity levels and others, to various incubation densities (number of eggs/litre of water) in flowing vs. stagnant water. Data analyses showed that, unaffected by raindrops (P&gt; 0.05), hatchability was inversely proportional to both turbidity (coefficient= -0.971) and incubation density (coefficient= -0.973). Only the properly constructed ponds (i.e., with elevated and compacted dykes) which do not receive any runoff should therefore be chosen for to hold incubation hapas, and the pond inlets should be turned off during heavy rainfall. Hatchability depression by stagnant water could be forestalled by limiting incubation density to 480 eggs / litre or by partially renewing the incubation water on a daily basis. By so doing, some Cameroon smallholders have successfully engaged in regular on-farm reproduction of Clarias gariepinus

Caffeine as an opioid analgesic adjuvant in fibromyalgia

J Ryan Scott,1 Afton L Hassett,1 Chad M Brummett,1 Richard E Harris,1,2 Daniel J Clauw,1,2 Steven E Harte1,2 1Chronic Pain and Fatigue Research Center, Department of Anesthesiology, 2Department of Internal Medicine, Division of Rheumatology, University of Michigan, Ann Arbor, MI, USA Background: Caffeine&rsquo;s properties as an analgesic adjuvant with nonsteroidal anti-inflammatory drugs/acetaminophen are well documented. However, little clinical research has explored ca&shy;ffeine&rsquo;s effects on opioid analgesia. This study assessed the effects of caffeine consumption on pain and other symptoms in opioid-using and nonusing chronic pain patients meeting the survey criteria for fibromyalgia. Materials and methods: Patients presenting to a university-based pain clinic completed validated self-report questionnaires assessing symptoms. Patients (N=962) meeting the fibromyalgia survey criteria were stratified by opioid use and further split into groups based on caffeine amount consumed per day (no caffeine, or low, moderate, high caffeine). Analysis of covariance with Dunnett&rsquo;s post hoc testing compared pain and symptom severity between the no caffeine group and the caffeine consuming groups. Results: In opioid users, caffeine consumption had modest but significant effects on pain, catastrophizing, and physical function. Lower levels of pain interference were associated with low and moderate caffeine use compared to no caffeine intake. Lower pain catastrophizing and higher physical function were observed in all caffeine dose groups, relative to the no caffeine group. Lower pain severity and depression were observed only in the moderate caffeine group. In opioid nonusers, low caffeine intake was associated with higher physical function; however, no other significant effects were observed. Conclusion: Caffeine consumption was associated with decreased pain and symptom severity in opioid users, but not in opioid nonusers, indicating caffeine may act as an opioid adjuvant in fibromyalgia-like chronic pain patients. These data suggest that caffeine consumption concomitant with opioid analgesics could provide therapeutic benefits not seen with opioids or caffeine alone. Keywords: caffeine, fibromyalgia, opioid analgesics, pain, analgesic adjuvant, chronic pai

Social-ecological analysis of integrated agriculture-aquaculture in Dedza, Malawi

Through the case of integrated agriculture-aquaculture in rural Malawi, this paper argues that hybrid research can reveal new interactions in social-ecological systems not evident when studies by social or natural methods independently. While recent research acknowledges the social and natural dimensions of aquaculture systems, studies often create an artificial divide by attempting to address each aspect in isolation. Social science research has overlooked the biophysical aspects of aquaculture, while scientific research has uncritically accepted orthodox explanations of environmental outcomes without addressing the social contexts of such systems. The social component of this research reveals that fish farmers in Malawi are rejecting practices which do not work in the local context (fertilization with pond mud) and adopting strategies that do work (irrigation with pond water). The physical component of this research compliments the social by elucidating that irrigation with pond water resulted in higher soil nutrient and moisture content. The paper concludes that small-scale aquaculture can make significant contributions to rural household food and income security in Africa and that hybrid research methods can improve our abilities to investigate the complex, connected nature of social-ecological systems