Search

In this paper, the symmetric positive semidefinite Procrustes problem is considered. By using matrix inner product and matrix decomposition theory, an explicit expression of the solution is given. Based on the explicit expression given in this paper, it is easy to derive the explicit expression of the solution given by Woodgate [K.G. Woodgate. Least-squares solution of F = PG over positive semidefinite symmetric P . Linear Algebra Appl., 245:171–190, 1996.] and by Liao [A.P. Liao. On the least squares problem of a matrix equation. J. Comput. Math., 17:589–594, 1999.] for the Procrustes problem in some special cases. The explicit expression given in this paper also shows that the solution of the special inverse eigenvalue problem considered by Zhang [L. Zhang. A class of inverse eigenvalue problem for symmetric nonnegative definite matrices. J. Hunan Educational Inst., 2:11–17, 1995 (in Chinese).] can be computed exactly. Examples to illustrate the correctness of the theory results are given.

Plants deploy different strategies to respond and adapt to various stresses. Given that stresses affect plant growth and activity, the responses and tolerance of crops to stresses must be improved through genetic engineering. Inducible promoters, which have vital roles in gene expression and function, are highly desired in biotechnology applications. Thus, novel inducible promoters must be isolated and identified for genetic engineering to improve crop stress responses and tolerance. OsRhoGAPs are involved in plant defense against diverse stresses. In this study, we identified OsRhoGAP2, which is preferentially expressed in rice inflorescences. We isolated the OsRhoGAP2 promoter and analyzed its functions in transgenic Arabidopsis. We fused the GUS reporter with six 5′ deletion fragments (gp1–gp6) of the OsRhoGAP2 promoter with different lengths. Through histochemical analysis, we detected GUS activity in the inflorescences of transgenic Arabidopsis containing gp1, gp3, gp4, and gp5 constructs but not in transgenic Arabidopsis containing gp2 and gp6 constructs. The GUS activity in transgenic plants containing gp1–gp6 constructs changed under different stress treatments. Bioinformatics analysis and experimental results revealed that the core fragment involved in the inflorescence-preferential expression of OsRhoGAP2 and stress responses may be located in the − 706 bp to + 1 bp, or the translated start site, of OsRhoGAP2. Results indicate that OsRhoGAP2 has a conserved role in stress tolerance and exhibits tissue-specific expression patterns in several plant species. This work provides novel insights into the appropriate promoter resources for plant genetic transformation and useful references for biotechnologists to improve stress tolerance in rice.

n this paper, an iterative method to solve one kind of nonlinear matrix equation is discussed. For each initial matrix with some conditions, the matrix sequences generated by the iterative method are shown to lie in a fixed open ball. The matrix sequences generated by the iterative method are shown to converge to the only solution of the nonlinear matrix equation in the fixed closed ball. In addition, the error estimate of the approximate solution in the fixed closed ball, and a numerical example to illustrate the convergence results are given.

Soil salinization due to seawater intrusion along coastal areas is an increasing threat to rice cultivation worldwide. While the detrimental impact on rice growth and yield has been thoroughly studied, little is known about how severe salinity affects structure and function of paddy soil microbial communities. Here, we examined their short-term responses to half- and full-strength seawater salinity in controlled laboratory experiments. Slurry microcosms were incubated under anoxic conditions, with rice straw added as carbon source. Stress exposure time was for 2 days after a pre-incubation period of 7 days. Relative to the control, moderate (300 mM NaCl) and high (600 mM NaCl) salt stress suppressed both net consumption of acetate and methane production by 50% and 70%, respectively. Correspondingly, community-wide mRNA expression decreased by 50–65%, with significant changes in relative transcript abundance of family-level groups. mRNA turnover was clearly more responsive to salt stress than rRNA dynamics. Among bacteria, Clostridiaceae were most abundant and the only group whose transcriptional activity was strongly stimulated at 600 mM NaCl. In particular, clostridial mRNA involved in transcription/translation, fermentation, uptake and biosynthesis of compatible solutes, and flagellar motility was significantly enriched in response salt stress. None of the other bacterial groups were able to compete at 600 mM NaCl. Their responses to 300 mM NaCl were more diverse. Lachnospiraceae increased, Ruminococcaceae maintained, and Peptococcaceae, Veillonellaceae, and Syntrophomonadaceae decreased in relative mRNA abundance. Among methanogens, Methanosarcinaceae were most dominant. Relative to other family-level groups, salt stress induced a significant enrichment of transcripts related to the CO dehydrogenase/acetyl-coenzyme A synthase complex, methanogenesis, heat shock, ammonium uptake, and thermosomes, but the absolute abundance of methanosarcinal mRNA decreased. Most strikingly, the transcriptional activity of the Methanocellaceae was completely suppressed already at 300 mM NaCl. Apparently, the key taxonomic groups involved in the methanogenic breakdown of plant polymers significantly differ in their ability to cope with severe salt stress. Presumably, this different ability is directly linked to differences in their genetic potential and metabolic flexibility to reassign available energy resources for cellular adaptation to salt stress.

e18003 Background: Medical advance in the recent decades has turned cancer into a chronic disease. At the same time, quality of life (LoF) during the treatment period has emerged as a new concern of cancer patients. Rehabilitation therapy, which can help patients conquer fear and be more engaged in the process, has gradually attracted more attentions in China. We designed a survey, for both the cancer patients and their families, to understand their view of the rehabilitation therapy. Methods: We sent paper-based surveys to volunteers consisted of cancer patients and their families. Majority of patients are from 10 cancer centers at the southwest region of China. The main cancer types are lung cancer, breast cancer and colon cancer. The survey questions focus on: patients and their families’ engagement of the treatment, their view on rehabilitation therapy, and their method preference for the rehabilitation therapy. Results: We sent 2,000 copies of the survey and received 1,920 valid inputs. Below are the key findings. 1. Their biggest concern: the outcome of the treatment 55.8%, side effects 19.7%, financial burden 12.8% and mental stress 11.5%. 2. The importance of the rehabilitation therapy as compared to traditional medical treatment, such as surgery and chemotherapy: equally important 67.8%, less important 17.7%, more important 10.1%, no preference 4.4%. 3. The necessity of rehabilitation therapy: very necessary 65.7%, somewhat necessary 22.7%, not necessary 11.6%. 4. The first three reasons for participating rehabilitation therapy: it helped go through the treatment 42.8%, it improved quality of life 31.6% and it helped release their mental stress 22.3%. 5. The best form to conduct rehabilitation therapy: face-to-face communicate with the doctors 60.6%, telecommunication 15.8% and combination of both 22.1%. Conclusions: The results of the survey strongly indicate the demands for rehabilitation therapy. Patients started to understand it – more than half of them think it is as important as the traditional medical treatment. Patients’ quality of life and mental health, which is part of the holistic treatment, are gradually recognized. Next, we plan to group our survey results by types of cancers, patients and their families’ genders and age, as well as the local economics, to better understand the data. We hope this study can serve as a data point to help build China’s rehabilitation therapy infrastructure.