Reseeding Technique Research Articles

Combining Rainwater Harvesting and Grass Reseeding to Revegetate Denuded African Semi-arid Landscapes

In African drylands, perennial grasses preferred by grazing livestock are disappearing at an alarming rate. This has led to recurrent livestock feed shortages threatening pastoralist’s livelihoods. Combining native grass reseeding and rainwater harvesting offers a viable and innovative solution to reverse this trend. However, studies to determine how biomass yields are affected by soil moisture availability attributed to in situ rainwater harvesting in African drylands are limited. We investigated how biomass yields of three grasses native to Africa, i.e., Enteropogon macrostachyus (Bush rye grass), Cenchrus ciliaris (African foxtail grass), and Eragrostis superba (Maasai love grass), are affected by soil moisture content in a typical semi-arid landscape. Rainwater harvesting structures included trenches, micro-catchments and furrows. Additionally, rain runoff was diverted from an adjacent road used as a catchment area. Soil moisture was measured between November 2018 and August 2019 using PlantCare Mini-Logger sensors installed at 40 and 50 cm depths and 0, 1, 5 and 15 m away from the trench. Quadrat method was used to determine biomass yields in August 2019. Peaks in soil moisture were observed after rainfall events. Soil moisture content gradually decreased after the rainy season, but was higher closer to the trench. This is attributed to the prolonged rainwater retention in the trenches. Biomass yields were in the order Eragrostis superba > Cenchrus ciliaris > Enteropogon macrostachyus. Biomass production was higher near the trenches for all the studied species. Sensitivity to soil moisture demonstrated by the magnitude to yield reduction during the growing season was in the order Eragrostis superba > Cenchrus ciliaris > Enteropogon macrostachyus. These results suggest that Eragrostis superba is more sensitive to drought stress than Enteropogon macrostachyus that is adapted to a wide range of soil moisture conditions. We demonstrated that in situ rainwater harvesting structures enhanced soil moisture availability and displayed great potential for revegetating denuded natural rangelands in semi-arid African landscapes. Thus, combining rainwater harvesting and reseeding techniques can produce measurable improvements in pastoral livelihoods and should be incorporated in dryland development policies in the region. Ultimately, incorporating such innovative strategies can strengthen the effectiveness of ecological restoration in African drylands to meet the objectives of the UN Decade on Ecosystem Restoration and achieving the UN Sustainable Development Goals.Graphical abstract

Abstract 2102: Assessing glioma-protein inhibition in sunitinib-resistance using a 3-dimentional tissue-engineered renal cell carcinoma patient derived model

Abstract Objective: To identify the role of glioma-proteins (Gli) in sunitinib-resistant metastatic renal cell carcinoma and the effect of Gli-inhibition using a 3D tissue-engineered patient-derived model. Background: Renal cell carcinoma (RCC) is the 6th most common malignancy with 2.3% annual increase in Canada. Metastatic RCC (mRCC) patients are treated with anti-angiogenic tyrosine kinase inhibitors (TKIs, sunitinib) as the first-line of treatment because mRCC tumor is heavily depend on VEGF pathway. Therefore, identifying the factor(s) responsible for sunitinib-resistance development and disease advancement in mRCC is imperative. Cancer reflect aspects of developmental patterning and the Hedgehog family proteins are known to play a central role. Among other proteins in the family, the inappropriate activation and/or maintenance of Sonic hedgehog (Shh)-Gli pathway results in various tumors. However, the potential of Shh-Gli pathway inhibitors in sunitinib-resistant mRCC have never been tested. To screen for effective Gli-inhibitors, we will use a 3D tissue-engineered patient-derived tumor model utilizing decellularized kidneys as matrices. Organ decellularization is the process of complete cell removal from the organ and maximum preservation of the extracellular matrix (ECM) microarchitecture, leaving some reported growth factors in which tumor cells from patients can be reseeded, regenerating the organ. This 3D-model is an economic and reliable platform to screen the Gli-inhibitors, and identify tumour-specific optimal therapies. Results: We established sunitinib-conditioned cell-line (Caki-1DC) from the parental cell-line (Caki-1WT) and a mouse model of acquired sunitinib-resistance. Proteomics and microarray results from these two models showed transcriptional and translational changes between the sensitive and resistant phenotypes, particularly in the Hedgehog signalling. In Caki-1DC, an upregulation of Gli-2 was observed, which could be abrogated with Shh pathway inhibitor, cyclopamine. Furthermore, in our decellularization and reseeding techniques of kidney, we have assessed cell viability for up to a month exhibiting adequate cell viability. This 3D platform will be used to assess the effectiveness of Gli-inhibitors. Conclusion: Our data from in vitro and in vivo models established Shh-Gli pathway activation in sunitinib-resistant mRCC. Testing the effectiveness of Gli-inhibitors will help tailor drugs for the patients to improve progression free survival. The 3D patient-derived mRCC platform will enable us to generate many in vitro avatars to accurately recreate the tumor of a patient, and simultaneously screen for suitable drugs and dose for the patient. The identification of the Shh-Gli driver pathway and the effective therapy will translate into improving patient’s quality of life and survival. Citation Format: Ninadh M. D'Costa, Zheng Tan, Claudia Chavez-Munoz, Alan So. Assessing glioma-protein inhibition in sunitinib-resistance using a 3-dimentional tissue-engineered renal cell carcinoma patient derived model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2102.

Evolution of graft morphology and function after recellularization of decellularized rat livers.

Decellularization of livers is a well-established procedure. Data on different reseeding techniques or the functional evolution and reorganization processes of repopulated grafts remains limited. A proprietary, customized bioreactor was established to repopulate decellularized rat livers (n = 21) with primary rat hepatocytes (150 × 106 cells) via the hepatic artery and to subsequently evaluate graft morphology and function during 7 days of ex vivo perfusion. Grafts were analysed at 1 h, 6 h, 12 h, 24 h, 3 days, 5 days and 7 days after recellularization (all n = 3) by immunohistological evaluation, hepatocyte-related enzyme (aspartate transaminase, alanine transaminase and lactate dehydrogenase) and albumin measurement in the perfusate. This appears to be the first available protocol for repopulation of rat livers via the hepatic artery. Within the first 24 h after repopulation, the hepatocytes seemed to migrate out of the vascular network and form clusters in the parenchymal space around the vessels. Graft function increased for the first 24 h after repopulation with a significantly higher function compared to standard two-dimensional culture after 24 h. Thereafter, graft function constantly decreased with significantly lower values after 6 days and 7 days of perfusion, although histologically viable hepatocytes were found even after this period. The data suggests that, owing to a constant loss of function, repopulated grafts should potentially be implanted as soon as cell engraftment and graft re-organization are completed. Copyright © 2016 John Wiley & Sons, Ltd.

Test Set Compression Through Alternation Between Deterministic and Pseudorandom Test Patterns

This paper presents a new reseeding technique that reduces the storage required for the seeds as well as the test application time by alternating between ATPG and reseeding to optimize the seed selection. The technique avoids loading a new seed into the PRPG whenever the PRPG can be placed in a state that generates test patterns without explicitly loading a seed. The ATPG process is tuned to target only undetected faults as the PRPG goes through its natural sequence which is maximally used to generate useful test patterns. The test application procedure is slightly modified to enable higher flexibility and more reduction in tester storage and test time. The results of applying the technique show up to 90% reduction in tester storage and 80% reduction in test time compared to classic reseeding. They also show 70% improvement in defect coverage when the technique is emulated on test chips with real defects.

Integrated LFSR Reseeding, Test-Access Optimization, and Test Scheduling for Core-Based System-on-Chip

We present a system-on-chip (SOC) testing approach that integrates test data compression, test-access mechanism/test wrapper design, and test scheduling. An efficient linear feedback shift register (LFSR) reseeding technique is used as the compression engine. All cores on the SOC share a single on-chip LFSR. At any clock cycle, one or more cores can simultaneously receive data from the LFSR. Seeds for the LFSR are computed from the care bits for the test cubes for multiple cores. We also propose a scan-slice-based scheduling algorithm that attempts to maximize the number of care bits the LFSR can produce at each clock cycle, such that the overall test application time (TAT) is minimized. This scheduling method is static in nature because it requires predetermined test cubes. We also present a dynamic scheduling method that performs test compression during test generation. Experimental results for International Symposium on Circuits and Systems and International Workshop on Logic and Synthesis benchmark circuits, as well as industrial circuits, show that optimum TAT, which is determined by the largest core, can often be achieved by the static method. If structural information is available for the cores, the dynamic method is more flexible, particularly since the performance of the static compression method depends on the nature of the predetermined test cubes.

A fast seed selection technique for cost effective hybrid pattern generation

In this paper, a fast seed selection implementation procedure for LFSR based pseudorandom pattern generation in hybrid technique is described. This selection technique reduced the pseudo-random patterns to detect most of the easy-to-detect faults. The stored patterns are then used to detect remaining hard-to-detect faults. Fast cost calculation methodology is used to determine the optimum ratio of pseudo-random and stored patterns in the hybrid technique. This process is able to execute fast 100% fault detection with minimum test time for both VLSI chip and system- on-chip (SoC) testing. The fault simulation results using pseudo-random patterns with the fast seed selection technique showed significant number of test patterns reduction (>50%) compared to reseeding technique. The stored patterns also detected the rest of the hard-to-detect faults with reduced number of patterns (<100). Fault simulation experiments both on pseudo-random and stored patterns in the hybrid technique also showed on the average better results than previous works (pseudo-random >40% and deterministic >20%).

COCULTURE OF BLADDER UROTHELIAL AND SMOOTH MUSCLE CELLS ON SMALL INTESTINAL SUBMUCOSA: POTENTIAL APPLICATIONS FOR TISSUE ENGINEERING TECHNOLOGY

COCULTURE OF BLADDER UROTHELIAL AND SMOOTH MUSCLE CELLS ON SMALL INTESTINAL SUBMUCOSA: POTENTIAL APPLICATIONS FOR TISSUE ENGINEERING TECHNOLOGY