30 research outputs found
Not Available
Not AvailableIntensification in rice crop production is generally understood as requiring increased use of
material inputs: water, inorganic fertilizers, and agrochemicals. However, this is not the
only kind of intensification available. More productive crop phenotypes, with traits such as
more resistance to biotic and abiotic stresses and shorter crop cycles, are possible through
modifications in the management of rice plants, soil, water, and nutrients, reducing rather
than increasing material inputs. Greater factor productivity can be achieved through the
application of new knowledge and more skill, and (initially) more labor, as seen from the
System of Rice Intensification (SRI), whose practices are used in various combinations by as
many as 10 million farmers on about 4 million hectares in over 50 countries. The highest
yields achieved with these management methods have come from hybrids and improved
rice varieties, confirming the importance of making genetic improvements. However,
unimproved varieties are also responsive to these changes, which induce better growth and
functioning of rice root systems and more abundance, diversity, and activity of beneficial
soil organisms. Some of these organisms as symbiotic endophytes can affect and enhance
the expression of rice plants' genetic potential as well as their phenotypic resilience to
multiple stresses, including those of climate change. SRI experience and data suggest that
decades of plant breeding have been selecting for the best crop genetic endowments under
suboptimal growing conditions, with crowding of plants that impedes their photosynthesis
and growth, flooding of rice paddies that causes roots to degenerate and forgoes benefits
derived from aerobic soil organisms, and overuse of agrochemicals that adversely affect
these organisms as well as soil and human health. This review paper reports evidence from
research in India and Indonesia that changes in crop and water management can improve
the expression of rice plants' genetic potential, thereby creating more productive and robust phenotypes from given rice genotypes. Data indicate that increased plant density does not
necessarily enhance crop yield potential, as classical breeding methods suggest. Developing
cultivars that can achieve their higher productivity under a wide range of plant
densitiesâbreeding for density-neutral cultivars using alternative selection strategiesâwill
enable more effective exploitation of available crop growth resources. Density-neutral
cultivars that achieve high productivity under ample environmental growth resources can
also achieve optimal productivity under limited resources, where lower densities can avert
crop failure due to overcrowding. This will become more important to the extent that
climatic and other factors become more adverse to crop production. Focusing more on
which management practices can evoke the most productive and robust phenotypes from
given genotypes is important for rice breeding and improvement programs since it is
phenotypes that feed our human populationsNot Availabl
A sparse deep learning approach for automatic segmentation of human vasculature in multispectral optoacoustic tomography.
Multispectral Optoacoustic Tomography (MSOT) resolves oxy- (HbO2) and deoxy-hemoglobin (Hb) to perform vascular imaging. MSOT suffers from gradual signal attenuation with depth due to light-tissue interactions: an effect that hinders the precise manual segmentation of vessels. Furthermore, vascular assessment requires functional tests, which last several minutes and result in recording thousands of images. Here, we introduce a deep learning approach with a sparse-UNET (S-UNET) for automatic vascular segmentation in MSOT images to avoid the rigorous and time-consuming manual segmentation. We evaluated the S-UNET on a test-set of 33 images, achieving a median DICE score of 0.88. Apart from high segmentation performance, our method based its decision on two wavelengths with physical meaning for the task-at-hand: 850 nm (peak absorption of oxy-hemoglobin) and 810 nm (isosbestic point of oxy-and deoxy-hemoglobin). Thus, our approach achieves precise data-driven vascular segmentation for automated vascular assessment and may boost MSOT further towards its clinical translation
Molecular characterization of chemical mutagenesis induced diversity in elite maize germplasm
Three classical breeding Iowa Super Stiff Stalk (SSS) inbred lines B37, B73 and B84, one Lancaster inbred Oh43 and mutant lines obtained by chemical mutagenesis followed by mutation breeding as follows: two of B37 and four of Oh43 were selected for molecular characterization. The mutant inbred lines were chosen because in addition to the improved GCA and SCA for grain yield, proven by their predominance in the Bulgarian breeding programs, they showed shifts in the flowering time as compared to the initial inbreds. Molecular markers (micro satellites and other PCR-based DNA markers) were used for characterization of maize genotypes and determination of the induced by chemical mutagenesis genetic variability in maize germplasm. The tested nine SSR markers (umc 1001, umclO14, umcl057, umcll81, umcl0lS, umc 1029. umcl003, umc 1033 and umcl035) can discriminate between the initial classical breeding inbred lines and the originating mutant inbreds. Allelic diversity was also studied by PCR amplification with specifically de-signed primers in the coding regions and flanking sequence of two genes: dwarf8 (d&: chromosome 1, 198.5 cM), and indeterminate l (id1; chromosome 1. 175.0 cM). These are considered candidate genes for variation in plant height and/or flowering time, based on mutant phenotypes and chromosomal locations near major QTLs. Single nucleotide polymorphisms and indels were detected in the region flanking the SH2 domain of dwarf8 gene in some of the mutant inbreds as a result of SSCP and sequencing analyses. However, these polymorphisms could not be associated with the observed variations in flowering time. PCR analysis of the promoter region dwarf8 showed a variant fragment of about 1 kb in the inbred line Oh43 that was not present in any other initial and mutant in-bred lines included in the study. PCR amplification of the 5' end of the Id1 coding sequence revealed polymorphic bands in the mutant lines XM535, XM521, XM250-l, XM98-8 and XM85-105, as well as in the classical breeding line B73. The data, presented here demonstrate the usefulness of chemical mutagenesis for generation of genetic diversity within the elite maize germplasm. Some of this variation may affect the major genes in the QTLs. Our initial data revealed mutagenesis induced polymorphisms in the coding sequences of two important for the determination of flowering time transcription factors. Further molecular analyses of the proposed model systems may complement the trait association efforts and will help to directly identify the major genes in the QTLs
Multispectral optoacoustic tomography of muscle perfusion and oxygenation under arterial and venous occlusion: A human pilot study.
Perfusion and oxygenation are critical parameters of muscle metabolism in health and disease. They have been both the target of many studies, in particular using near-infrared spectroscopy (NIRS). However, difficulties with quantifying NIRS signals have limited a wide dissemination of the method to the clinics. Our aim was to investigate whether clinical multispectral optoacoustic tomography (MSOT) could enable the label-free imaging of muscle perfusion and oxygenation under clinically relevant challenges: the arterial and venous occlusion. We employed a hybrid clinical MSOT/ultrasound system equipped with a hand-held scanning probe to visualize hemodynamic and oxygenation changes in skeletal muscle under arterial and venous occlusions. Four (N = 4) healthy volunteers were scanned over the forearm for both 3-minute occlusion challenges. MSOT-recorded pathophysiologically expected results during tests of disturbed blood flow with high resolution and without the need for contrast agents. During arterial occlusion, MSOT-extracted Hb-values showed an increase, while HbO(2)- and total blood volume (TBV)-values remained roughly steady, followed by a discrete increase during the hyperemic period after cuff deflation. During venous occlusion, results showed a clear increase in intramuscular HbO(2), Hb and TBV within the segmented muscle area. MSOT was found to be capable of label-free non-invasive imaging of muscle hemodynamics and oxygenation under arterial and venous occlusion. We introduce herein MSOT as a novel modality for the assessment of vascular disorders characterized by disturbed blood flow, such as acute limb ischemia and venous thrombosis
Multispectral optoacoustic tomography of peripheral arterial disease based on muscle hemoglobin gradients-a pilot clinical study.
Background: Current imaging assessment of peripheral artery disease (PAD) relies on anatomical cross-sectional visualizations of the affected arteries. Multispectral optoacoustic tomography (MSOT) is a novel molecular imaging technique that provides direct and label-free visualizations of soft tissue perfusion and oxygenation. Methods: MSOT was prospectively assessed in a pilot trial in healthy volunteers (group n1=4, mean age 31, 50% male and group n3=4, mean age 37.3, 75% male) and patients with intermittent claudication (group n2=4, mean age 72, 75% male, PAD stage IIb). We conducted cuff-induced ischemia (group n1) and resting state measurements (groups n2 and n3) over the calf region. Spatially resolved mapping of oxygenated (HbO2), deoxygenated (Hb) and total (THb) hemoglobin, as well as oxygen saturation (SO2), were measured via hand-held hybrid MSOT-Ultrasound based purely on hemoglobin contrast. Results: Calf measurements in healthy volunteers revealed distinct dynamics for HbO2, Hb, THb and SO2 under cuff-induced ischemia. HbO2, THb and SO2 levels were significantly impaired in PAD patients compared to healthy volunteers (P<0.05 for all parameters). Revascularization led to significant improvements in HbO2 of the affected limb. Conclusions: Clinical MSOT allows for non-invasive, label-free and real-time imaging of muscle oxygenation in health and disease with implications for diagnostics and therapy assessment in PAD
Cardiovascular optoacoustics: From mice to men - A review.
Imaging has become an indispensable tool in the research and clinical management of cardiovascular disease (CVD). An array of imaging technologies is considered for CVD diagnostics and therapeutic assessment, ranging from ultrasonography, X-ray computed tomography and magnetic resonance imaging to nuclear and optical imaging methods. Each method has different operational characteristics and assesses different aspects of CVD pathophysiology; nevertheless, more information is desirable for achieving a comprehensive view of the disease. Optoacoustic (photoacoustic) imaging is an emerging modality promising to offer novel information on CVD parameters by allowing high-resolution imaging of optical contrast several centimeters deep inside tissue. Implemented with illumination at several wavelengths, multi-spectral optoacoustic tomography (MSOT) in particular, is sensitive to oxygenated and deoxygenated hemoglobin, water and lipids allowing imaging of the vasculature, tissue oxygen saturation and metabolic or inflammatory parameters. Progress with fast-tuning lasers, parallel detection and advanced image reconstruction and data-processing algorithms have recently transformed optoacoustics from a laboratory tool to a promising modality for small animal and clinical imaging. We review progress with optoacoustic CVD imaging, highlight the research and diagnostic potential and current applications and discuss the advantages, limitations and possibilities for integration into clinical routine
Highâthroughput phenotyping of soybean genotypes under base saturation stress conditions
Clinical and Translational Imaging and Sensing of Diabetic Microangiopathy: A Narrative Review
Microvascular changes in diabetes affect the function of several critical organs, such as the kidneys, heart, brain, eye, and skin, among others. The possibility of detecting such changes early enough in order to take appropriate actions renders the development of appropriate tools and techniques an imperative need. To this end, several sensing and imaging techniques have been developed or employed in the assessment of microangiopathy in patients with diabetes. Herein, we present such techniques; we provide insights into their principles of operation while discussing the characteristics that make them appropriate for such use. Finally, apart from already established techniques, we present novel ones with great translational potential, such as optoacoustic technologies, which are expected to enter clinical practice in the foreseeable future