A simple field based method for rapid wood density estimation for selected tree species in Western Kenya

Wood density is an important variable for accurate quantification of woody biomass and carbon stocks. Conventional destructive methods for wood density estimation are resource intensive, prohibiting their use, limiting the application of approaches that would minimize uncertainties in tree biomass estimates. We tested an alternative method involving tree coring with a carpenter's auger to estimate wood density of seven tropical tree species in Western Kenya. We used conventional water immersion method to validate results from the auger core method. The mean densities (and 95% confidence intervals) ranged from 0.36 g cm−3 (0.25–0.47) to 0.67 g cm−3 (0.61–0.73) for the auger core method, and 0.46 g cm−3 (0.42–0.50) to 0.67 g cm−3 (0.61–0.73) for the water immersion method. The auger core and water immersion methods were not significantly different for four out of seven tree species namely; Acacia mearnsii, Mangifera indica, Eucalyptus grandis and Grevillea robusta. However, wood densities estimated from the auger core method were lower (t (61) = 7.992, P = <0.001). The ease of the auger core method application, as a non-destructive method in acquiring wood density data, is a worthy alternative in biomass and carbon stocks quantification. This method could protect trees outside forests found in most parts of Africa

FTIR-DRIFTS-based prediction of β-carotene, α-tocopherol and L-ascorbic acid in mango (Mangifera indica L.) fruit pulp

Mango fruits contain substantial vitamins and dietary fibre. Vitamins vary among and within fruits depending on cultivar type and ripening stage. Conventional techniques of vitamins analysis are based on High Pressure Liquid Chromatography, which are costly and laborious. This study evaluated the potential of Fourier transform infrared-diffuse reflectance spectroscopy (FTIR-DRIFTS) technique in predicting β-carotene, α-tocopherol and L-ascorbic acid in pulps of four mango cultivar types (‘Apple’, ‘Kent’, ‘Ngowe’, and ‘Tommy Atkins’). Combination of ran dom forest (RF) and first derivative spectra developed the predictive models. Factorial ANOVA examined the interaction effect of cultivar type, site (‘Thika’, ‘Embu’ and ‘Machakos), and fruit canopy position (sun exposed/within crown) on β-carotene, α-tocopherol and L-ascorbic acid contents. RF Models gave R2 = 0.97, RMSE = 2.27, RPD = 0.72 for β-carotene; R2 = 0.98, RMSE = 0.26, RPD = 0.30 for α-tocopherol and R2 = 0.96, RMSE = 0.51, RPD = 1.96 for L-ascorbic acid. Generally cultivar type affected vitamin C, F (3, 282) = 7.812, p < 0.05. Apple and Tommy Atkins had higher mean vitamins than Ngowe and Kent. In Machakos, within canopy fruits had higher β-carotene than sun-exposed fruits, F (5, 257) = 2.328, p = 0.043. However, interactions between fruit position, site and cultivar did not affect α-tocopherol and vitamin C. In Thika, Tommy Atkins at fully ripe stage had higher vitamin C than at intermediate maturity stage, F (2, 143) = 7.328, p = 0.01. These results show that FTIR-DRIFTS spectroscopy is a high-throughput method that can be used to predict mango fruit vitamins of in a large data set

Nutritional diversity of leafy amaranth species grown in Kenya

Objectives: Despite the availability of many species of amaranth in Kenya, there is inadequate information on their nutritional diversity and how they can be best used in mitigation of malnutrition. Hence, this study was aimed at investigating the nutritional diversity of five leafy amaranth species grown in Kenya. Methodology and results: Amaranth vegetables were harvested 5-6 weeks after planting. They were analyzed for their nutritional and phytochemical content using standard methods. Moisture content was lowest in A.cruentus (79.29±1.26%). A.cruentus had the highest protein (4.37 ±0.02%).The fat content of A.hybridus (2.53±0.06%) and A.hypochodriacus (2.63±0.11%) was significantly higher than the other species. The crude fibre content (3.01±0.29%) was similar in all the species. A.dubius had the highest calcium (336.47±0.9mg/100g) and iron (18.64±0.23mg/100g) while A.cruentus was highest in zinc content (1.67±0.03mg/100g).The total phenols content was highest in A.cruentus (3.59±0.01GAE/100mg).Catechins were highest in A.cruentus (7.15±0.63CE/100mg) while quercetin was highest in A.cruentus (14.28±0.86QE/100mg). Conclusion and application of results: More than 50% of the Kenyan population live below the poverty line and lack access to adequate food. The food available food is of poor nutritional value, this causes malnutrition and other nutritional disorders. There is therefore a need to identify nutrient-rich foods that can be produced inexpensively to meet the nutrient requirements of everyone and especially the vulnerable groups, such as pregnant women, children and the elderly. Amaranth is drought tolerant, grows fast and is easily cultivated. This study indicates that the Amaranth species found in Kenya are a good source of key nutrients, which can be used in mitigation of malnutrition. A.dubius is a superior source of calcium and iron and can help curb the micronutrient deficiencies in Kenya, while A.cruentus is a superior source of protein and phytochemicals which are important in reducing the risk of chronic diseases which are so rampant in Kenya today.Keywords: A. dubius; A. hybridus and A. cruentus; A. albus and A. hypochondriacus; Nutrient

Morphological diversity of mango germplasm from the upper Athi River region of Eastern Kenya: An analysis based on non- fruit descriptors

Phenotypic variation in plants can be evaluated by morphological characterization using visual attributes. Fruits have been the major descriptors for identification of different varieties of fruit crops. However, even in their absence, farmers, breeders and interested stakeholders require to distinguish between different mango varieties. This study aimed at determining diversity in mango germplasm from the Upper Athi River (UAR) and providing useful alternative descriptors for the identification of different mango varieties in the absence of fruits. A total of 20 International Plant Genetic Resources Institute (IPGRI) descriptors for mango were selected for use in the visual assessment of 98 mango accessions from 15 sites of the UAR region of eastern Kenya. Purposive sampling was used to identify farmers growing diverse varieties of mangoes. Evaluation of the descriptors was performed on-site and the data collected were then subjected to multivariate analysis including Principal Component Analysis (PCA) and Cluster analysis, one- way analysis of variance (ANOVA) and Chi square tests. Results classified the accessions into two major groups corresponding to indigenous and exotic varieties. The PCA showed the first six principal components accounting for 75.12% of the total variance. A strong and highly significant correlation was observed between the color of fully grown leaves, leaf blade width, leaf blade length and petiole length and also between the leaf attitude, color of young leaf, stem circumference, tree height, leaf margin, growth habit and fragrance. Useful descriptors for morphological evaluation were 14 out of the selected 20; however, ANOVA and Chi square test revealed that diversity in the accessions was majorly as a result of variations in color of young leaves, leaf attitude, leaf texture, growth habit, leaf blade length, leaf blade width and petiole length traits. These results reveal that mango germplasm in the UAR has significant diversity and that other morphological traits apart from fruits can be useful in morphological characterization of mango.Keywords: Mango, morphological characterization, Principal Component Analysis, IPGRI, eastern Keny

Chemical genetic identification of CDKL5 substrates reveals its role in neuronal microtubule dynamics.

Loss-of-function mutations in CDKL5 kinase cause severe neurodevelopmental delay and early-onset seizures. Identification of CDKL5 substrates is key to understanding its function. Using chemical genetics, we found that CDKL5 phosphorylates three microtubule-associated proteins: MAP1S, EB2 and ARHGEF2, and determined the phosphorylation sites. Substrate phosphorylations are greatly reduced in CDKL5 knockout mice, verifying these as physiological substrates. In CDKL5 knockout mouse neurons, dendritic microtubules have longer EB3-labelled plus-end growth duration and these altered dynamics are rescued by reduction of MAP1S levels through shRNA expression, indicating that CDKL5 regulates microtubule dynamics via phosphorylation of MAP1S. We show that phosphorylation by CDKL5 is required for MAP1S dissociation from microtubules. Additionally, anterograde cargo trafficking is compromised in CDKL5 knockout mouse dendrites. Finally, EB2 phosphorylation is reduced in patient-derived human neurons. Our results reveal a novel activity-dependent molecular pathway in dendritic microtubule regulation and suggest a pathological mechanism which may contribute to CDKL5 deficiency disorder

Effects of Triton X-100 concentration and incubation temperature on carboxyfluorescein release from multilamellar liposomes

Carboxyfluorescein is the most commonly used probe to measure the rate of release of vesicle contents. The validity of the data obtained by this method depends on obtaining an end point based on the complete release of the dye on treatment of the liposomes with a detergent, usually Triton X-100. However, Triton does not completely release entrapped carboxyfluorescein from multilamellar liposomes and the amount and rate of release of marker upon detergent treatment is a function of lipid composition of the liposome, Triton concentration and temperature and duration of detergent incubation. The fluorescence `end point' for distearoyl--[alpha]-phosphatidylcholine/cholesterol (2:1, mol%) multilamellar liposomes treated with 0.5% Triton at 22[deg]C (a condition often used) is only about one-fifth the value for liposomes treated with 5% Triton at 72[deg]C. The conditions of treatment appear to affect the release of carboxyfluorescein from the lipid of the partially or completely disrupted liposome and the subsequent partitioning of the free dye into the aqueous phase. This effect can lead to serious errors in the interpretation of multilamellar liposome stability data. However, Triton allows complete release of entrapped dye from small unilamellar vesicles under all conditions tested.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26095/1/0000171.pd

Atmosfera modificada na conservação pós-colheita de Uva 'Centennial Seedless' .

Técnicas como armazenamento refrigerado e uso de atmosfera modificada em uvas são eficientes contra a degrana e a incidência de podridões, problemas que afetam diretamente a qualidade e a conservação pós-colheita das frutas. A cultivar Centennial Seedless apresenta potencial de consumo como uva fina de mesa devido à ausência de sementes. Objetivou-se nesse trabalho verificar o efeito da aplicação de atmosfera modificada passiva, com a utilização de filmes para embalagem na conservação pós-colheita de uvas cv. Centennial Seedless. Os frutos foram colhidos no estádio de casca verde amarelado, transportados, selecionados e acondicionados em diferentes filmes para embalagem: polietileno de baixa densidade (PEBD - 10 e 20 ?m) e polipropileno (PP - 6 e 10 ?m). Frutos não embalados foram utilizados como controle. Os cachos foram armazenados em câmara fria a 1°C e 85-90% UR durante 80 dias, sendo analisados a cada 20 dias, mais três dias a 22°C simulando-se a comercialização. Foram analisados: índice de abscisão das bagas, índice de podridões, desidratação do engaço e índice de escurecimento do engaço. O delineamento experimental adotado foi o inteiramente ao acaso em fatorial 5 x 4 (5 tratamentos e 4 períodos de armazenamento). Foram utilizadas 4 repetições de 3 cachos por tratamento. Os resultados foram submetidos à análise de variância e as médias foram comparadas pelo teste da diferença mínima significativa (p<0,05). Valores baixos de abscisão de bagas (3%) foram encontrados nos frutos embalados com o filme PP durante o armazenamento. A amostra controle foi a que apresentou maiores índices de podridão em todos os períodos avaliados. A desidratação do engaço foi semelhante nos tratamentos com embalagem nos períodos de comercialização simulada. As embalagens foram eficientes contra o escurecimento do engaço. Os resultados mostraram que o filme polipropileno foi o que melhor conservou a qualidade das uvas cv. Centennial Seedless

Impact of b-value on estimates of apparent fibre density

Recent advances in diffusion magnetic resonance imaging (dMRI) analysis techniques have improved our understanding of fibre-specific variations in white matter microstructure. Increasingly, studies are adopting multi-shell dMRI acquisitions to improve the robustness of dMRI-based inferences. However, the impact of b-value choice on the estimation of dMRI measures such as apparent fibre density (AFD) derived from spherical deconvolution is not known. Here, we investigate the impact of b-value sampling scheme on estimates of AFD. First, we performed simulations to assess the correspondence between AFD and simulated intra-axonal signal fraction across multiple b-value sampling schemes. We then studied the impact of sampling scheme on the relationship between AFD and age in a developmental population (n=78) aged 8-18 (mean=12.4, SD=2.9 years) using hierarchical clustering and whole brain fixel-based analyses. Multi-shell dMRI data were collected at 3.0T using ultra-strong gradients (300 mT/m), using 6 diffusion-weighted shells ranging from 0 – 6000 s/mm2. Simulations revealed that the correspondence between estimated AFD and simulated intra-axonal signal fraction was improved with high b-value shells due to increased suppression of the extra-axonal signal. These results were supported by in vivo data, as sensitivity to developmental age-relationships was improved with increasing b-value (b=6000 s/mm2, median R2 = .34; b=4000 s/mm2, median R2 = .29; b=2400 s/mm2, median R2 = .21; b=1200 s/mm2, median R2 = .17) in a tract-specific fashion. Overall, estimates of AFD and age-related microstructural development were better characterised at high diffusion-weightings due to improved correspondence with intra-axonal properties

Pengenalan Permainan Sains Bagi Siswa SDK Tes Kecamatan Bikomi Utara,Timor Tengah Utara

Abstrak Pengabdian ini bertujuan untuk menciptakan, menimbulkan kesukaan, dan ketertarikan siswa terhadap pelajaran sains, mengenalkan beberapa macam alat sederhana dan penggunaannya, mengetahui dan melaksanakan praktikum fisika, kimia dan biologi sederhana yang bisa dilakukan dengan memanfaatkan alat dan bahan yang tersedia di SDK Tes. Kegiatan pengabdian ini dilaksanakan di&nbsp; SDK Tes pada hari Rabu tanggal 16 Agustus 2017. Materi pengabdian berupa materi permainan sains, antara lain perbedaan tekanan udara, uangku terbakar uangku utuh, mengapung atau tidak mengapung, membuat magnet sederhana, memahami prinsip kayu (dayung), posisi air pada gelas besar terbalik, cangkang telur jauh lebih kuat dari yang terlihat, telur ajaib, kekuatan air, pembiasan cahaya, udara dan pembakaran, tes kerapatan. Pelaksanaan demonstrasi tersebut dilakukan dengan menggunakan interaksi yang baik antara siswa dengan guru. Siswa tidak malu untuk bertanya dengan guru. Hal ini memudahkan siswa memecahkan masalah yang dihadapinya. Selain itu, guru tidak menggerutu atau memarahi siswa yang mengalami kegagalan dalam melakukan percobaan atau demonstrasi. Para siswa SDK Tes sangat antusias, aktif, interaktif dan tidak kaku dalam belajar IPA. Para guru&nbsp; SDK Tes mengenal praktikum sains (Fisika, Kimia dan Biologi) sederhana yang bisa dilakukan dengan memanfaatkan alat dan bahan yang tersedia di lingkungan sekitar

Chemical and pasting properties of potato flour (Solanum tuberosum L.) in relation to different processing techniques

Open Access ArticleProcessing potato tubers into flour can be done using various methods, which can impact the flour’s nutritional and pasting properties. This study evaluated the effects of five different processing methods, namely, low-temperature blanching, followed by oven drying (LTB_OD), high-temperature blanching followed by oven drying (HTB_OD), boiling followed by oven drying (Boiling_OD), freeze drying (FD), and oven drying (OD), on the nutritional and pasting properties of potato flour derived from Shangi potato variety. The relationships between the nutritional and pasting properties were determined using Pearson’s correlation and principal component analyses (PCA). The results indicated that freeze-dried flour exhibited higher protein content (10.17%), sucrose (88.87 mg/100 g), and magnesium (44.90 mg/100 g) content, while Boiling_OD flour showed the lowest protein (6.41%), sucrose (15.34 mg/100 g), and magnesium (35.55 mg/100 g) content. All potato flour types demonstrated a decrease in apparent viscosity with increasing shear rate, with freeze-dried flour having the highest apparent viscosity. Freeze-dried flour showed the highest peak viscosity (7098.33 cP) and breakdown viscosity (2672.00 cP). The highest final viscosity (7989.00 cP) was recorded in HTB_OD flour. Protein (r = −0:92), fiber (r = −0:81), and fat (r = −0:83) negatively correlated with the peak viscosity, while sugars (glucose (r = 0:95), fructose (r = 0:93), and sucrose (r = 0:87)) and phosphorus (r = 0:86) positively correlated with pasting properties. The first two principal components explained 90.2% of the total variance. Oven drying and freeze drying were in close proximity in the PCA score plot, indicating that these two flour types have similar chemical and pasting properties. In conclusion, the different processing methods altered the chemical and pasting properties of the flour, therefore influencing their potential use in the food industry. Considering the correlations established in this study, it is likely that chemical properties could be used to predict the pasting properties of potato flour