31 research outputs found
Ambiguous Rationality: The Structural Design of Alvar Aalto
Unlike "humanizing", "expressive forms", and "phenomenological significance of materials", Aalto's structural conception has been seldom recognized as masterly touches and even misunderstood by some theorists as "a-tectonic" and "irrational." Since initiating practice, he had developed a "surface + frame" composite as a structural solution. Then a "thick partition" formed with ambient spaces, became a basis to fully explore in spatial, lighting, and signifying dimensions, breaking a new path long before the "skin + bone" prototype of modern architecture received sublation from the younger generation. This paper chooses three built churches throughout Aalto's career for a serial case study and reveals, through analyses from drawings to actual construction, how the composite system acts as a reasonable stress system and construction basis, participating in controlling the force system and force flows, how the "thick partition" mediates the spatial flows and directs the light-shadow interplay, and how such webs of significance have transcended the high modern architecture.Peer reviewe
Study on bearing mechanical and thermal characteristic evolvement rules affected by higher ambient temperature
In this paper, the bearing mechanical characteristics and thermal characteristics as it is running under constant speed (2400 r/min) and constant temperature (100 ℃) adopting bearing mechanical-thermal coupling model built on the basis of quasi-statics and elastohydrodynamic lubrication theory are discussed. Among which, the contact deformation between ball and inner/outer ring has same evolution law, besides, the same as the amplitude. Whose curve shape changes in the form of “circular-oblique D”, its amplitude rearches minimum value at 10thd3h between the location of 120° and 270°. The curve shapes belonging to contact angular between ball and inner/outer ring are similar to “circular”. There is opposite trend of them within the range of 90-300°. The amplitude of contact angular between ball and outer ring is the minimum at 10thd3h and 11thd1h. At the same time, the amplitude of that between ball and inner ring is the maximum. The evolution rules of contact stiffness between ball and inner/outer ring are generally consistent, which are similar to “crab”. But the amplitude of that between ball and outer ring is dominant. The maximum value of them occurs at 10thd3 and 11thd1h. The evolvement tendency of node temperatures maintains stable. Thereinto, the temperature of inner ring equals to that of contact location between ball and inner ring, which is the maximum value. It is obvious that ME, MD, MS, MCB, MCR and MOil devote themselves to heat production, the contribution rates of ME, MS, MCB and MCR are 100 %, the contribution rate of MD ranges from 52.6 % to 65.2 %. However, the amplitudes of friction moments have the opposite trend compared to “heat contribution factor”. The expansion amount owing to heat production is dominant in displacement variation and the effect of clearance on displacement can be ignored, whose evolution rules are contrary. The evolution rules of oil film thickness and oil film stiffness between ball and inner/outer ring are alike. Among which, the oil film thickness between ball and outer ring is dominant, its maximum value emerges at 10thd3h. The curve shapes of oil film stiffness between ball and outer/inner ring are oblique “D”, their amplitudes reach the maximum at 11thd1h-11thd3h
Identification of the GRAS gene family in the Brassica juncea genome provides insight into its role in stem swelling in stem mustard
GRAS transcription factors are known to play important roles in plant signal transduction and development. A comprehensive study was conducted to explore the GRAS family in the Brassica juncea genome. A total of 88 GRAS genes were identified which were categorized into nine groups according to the phylogenetic analysis. Gene structure analysis showed a high group-specificity, which corroborated the gene grouping results. The chromosome distribution and sequence analysis suggested that gene duplication events are vital for the expansion of GRAS genes in the B. juncea genome. The changes in evolution rates and amino acid properties among groups might be responsible for their functional divergence. Interaction networks and cis-regulatory elements were analyzed including DELLA and eight interaction proteins (including four GID1, two SLY1, and two PIF3 proteins) that are primarily involved in light and hormone signaling. To understand their regulatory role in growth and development, the expression profiles of BjuGRASs and interaction genes were examined based on transcriptome data and qRT-PCR, and selected genes (BjuGRAS3, 5, 7, 8, 10, BjuB006276, BjuB037910, and BjuA021658) had distinct temporal expression patterns during stem swelling, indicating that they possessed diverse regulatory functions during the developmental process. These results contribute to our understanding on the GRAS gene family and provide the basis for further investigations on the evolution and functional characterization of GRAS genes
Advances in anti-tumor based on various anaerobic bacteria and their derivatives as drug vehicles
Cancer therapies, such as chemotherapy and radiotherapy, are often unsatisfactory due to several limitations, including drug resistance, inability to cross biological barriers, and toxic side effects on the body. These drawbacks underscore the need for alternative treatments that can overcome these challenges and provide more effective and safer options for cancer patients. In recent years, the use of live bacteria, engineered bacteria, or bacterial derivatives to deliver antitumor drugs to specific tumor sites for controlled release has emerged as a promising therapeutic tool. This approach offers several advantages over traditional cancer therapies, including targeted drug delivery and reduced toxicity to healthy tissues. Ongoing research in this field holds great potential for further developing more efficient and personalized cancer therapies, such as E. coli, Salmonella, Listeria, and bacterial derivatives like outer membrane vesicles (OMVs), which can serve as vehicles for drugs, therapeutic proteins, or antigens. In this review, we describe the advances, challenges, and future directions of research on using live bacteria or OMVs as carriers or components derived from bacteria of delivery systems for cancer therapy
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Significance Tests for Random Effects and Correction for Bias of Estimated QTL Variances in GWAS
Genome-wide association study (GWAS) has became a powerful tool for revealing the genetic architecture of complex traits in plant studies, animal research and human disease. This method involves scanning genotypes from many different samples to study the associations between genetic markers and phenotypes. With the availability of low-costing and high-throughput technology, large-scale data are provided for analysis and efficient algorithms are needed to scan up to millions markers. Large-scale genomic study also involves high-dimensional statistics, which brings out lots of difficulties in modeling and computation in practice. This dissertation addresses two problems in GWAS, that are, the computational efficiency of marker scanning and correction of Beavis effect. The interesting connection between the fixed effect and the random effect in a linear mixed model is the inspiration for the current work. The methods we proposed are fully supported theoretically and empirically. In the first half of this dissertation, we investigate the significant test of markers in GWAS and propose a method for constructing a de-shrink Ridge estimator. This enables us to scan all the markers simultaneously in one model. The de-shrink estimators and test statistic are fast to compute. They also have comparable level as the conventional GWAS approaches, such as efficient mixed model association (EMMA). We also prove that given sufficient information the de-shrink estimators are asymptotically equivalent to the fixed effect estimators in EMMA.The second half of this dissertation is focusing on correcting the bias caused by the Beavis effect in GWAS. The Beavis effect refers to a phenomenon that the average effect size of the detected locus is inflated due to statistical tests. There is an increasing interest in applying linear mixed model in GWAS and the scanned marker is typically treated as fixed effect, which is called fixed model (FM) approach. Another way to tackle the same problem is considering the marker effect as random and this method is called random model (RM) approach. However, the random term results in extra computational burden. We develop a novel random fixed approach (RFM) to relieve the computational difficulties. Taking advantage of RFM and the censoring fact, we propose an efficient way to correct the Beavis effect. We demonstrate the method in simulated dataset and real data applications
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Significance Tests for Random Effects and Correction for Bias of Estimated QTL Variances in GWAS
Genome-wide association study (GWAS) has became a powerful tool for revealing the genetic architecture of complex traits in plant studies, animal research and human disease. This method involves scanning genotypes from many different samples to study the associations between genetic markers and phenotypes. With the availability of low-costing and high-throughput technology, large-scale data are provided for analysis and efficient algorithms are needed to scan up to millions markers. Large-scale genomic study also involves high-dimensional statistics, which brings out lots of difficulties in modeling and computation in practice. This dissertation addresses two problems in GWAS, that are, the computational efficiency of marker scanning and correction of Beavis effect. The interesting connection between the fixed effect and the random effect in a linear mixed model is the inspiration for the current work. The methods we proposed are fully supported theoretically and empirically. In the first half of this dissertation, we investigate the significant test of markers in GWAS and propose a method for constructing a de-shrink Ridge estimator. This enables us to scan all the markers simultaneously in one model. The de-shrink estimators and test statistic are fast to compute. They also have comparable level as the conventional GWAS approaches, such as efficient mixed model association (EMMA). We also prove that given sufficient information the de-shrink estimators are asymptotically equivalent to the fixed effect estimators in EMMA.The second half of this dissertation is focusing on correcting the bias caused by the Beavis effect in GWAS. The Beavis effect refers to a phenomenon that the average effect size of the detected locus is inflated due to statistical tests. There is an increasing interest in applying linear mixed model in GWAS and the scanned marker is typically treated as fixed effect, which is called fixed model (FM) approach. Another way to tackle the same problem is considering the marker effect as random and this method is called random model (RM) approach. However, the random term results in extra computational burden. We develop a novel random fixed approach (RFM) to relieve the computational difficulties. Taking advantage of RFM and the censoring fact, we propose an efficient way to correct the Beavis effect. We demonstrate the method in simulated dataset and real data applications
Enantioseparation of napropamide by supercritical fluid chromatography: Effects of the chromatographic conditions and separation mechanism
Supercritical fluid chromatography (SFC) is already used for enantioseparation in the pharmaceutical industry, but it is rarely used for the separation of chiral pesticides. Comparing with high performence liquid chromatography, SFC uses much more environmnetal friendly and economic mobile phase, supercritical CO2. In our work, the enantioseparation of an amide herbicide, napropamide, using three different polysaccharide‐type chiral stationary phases (CSPs) in SFC was investigated. By studying the effect of different CSPs, organic modifiers, temperature, back‐pressure regulator pressures, and flow rates for the enantioseparation of napropamide, we established a rapid and green method for enantioseparation that takes less than 2 minutes: The column was CEL2, the mobile phase was CO2 with 20% 2‐propanol, and the flow rate was 2.0 mL/min. We found that CEL2 demonstrated the strongest resolution capability. Acetonitrile was favored over alcoholic solvents when the CSP was amylose and 2‐propanol was the best choice when using cellulose. When the concentration of the modifiers or the flow rate was decreased, resolutions and analysis times increased concurrently. The temperature and back‐pressure regulator pressure exhibited only minor influences on the resolution and analysis time of the napropamide enantioseparations with these chiral columns. The molecular docking analysis provided a deeper insight into the interactions between the enantiomers and the CSPs at the atomic level and partly explained the reason for the different elution orders using the different chiral columns
Enantioseparation of napropamide by supercritical fluid chromatography: Effects of the chromatographic conditions and separation mechanism
Supercritical fluid chromatography (SFC) is already used for enantioseparation in the pharmaceutical industry, but it is rarely used for the separation of chiral pesticides. Comparing with high performence liquid chromatography, SFC uses much more environmnetal friendly and economic mobile phase, supercritical CO2. In our work, the enantioseparation of an amide herbicide, napropamide, using three different polysaccharide‐type chiral stationary phases (CSPs) in SFC was investigated. By studying the effect of different CSPs, organic modifiers, temperature, back‐pressure regulator pressures, and flow rates for the enantioseparation of napropamide, we established a rapid and green method for enantioseparation that takes less than 2 minutes: The column was CEL2, the mobile phase was CO2 with 20% 2‐propanol, and the flow rate was 2.0 mL/min. We found that CEL2 demonstrated the strongest resolution capability. Acetonitrile was favored over alcoholic solvents when the CSP was amylose and 2‐propanol was the best choice when using cellulose. When the concentration of the modifiers or the flow rate was decreased, resolutions and analysis times increased concurrently. The temperature and back‐pressure regulator pressure exhibited only minor influences on the resolution and analysis time of the napropamide enantioseparations with these chiral columns. The molecular docking analysis provided a deeper insight into the interactions between the enantiomers and the CSPs at the atomic level and partly explained the reason for the different elution orders using the different chiral columns
Enantioselective effects of chiral amide herbicides napropamide, acetochlor and propisochlor: The more efficient R-enantiomer and its environmental friendly
Amide herbicides, which are used extensively worldwide, are often chiral. Enantiomeric selectivity comes from the different effects of the enantiomers on target and non-target organisms. In this study, the enantiomers of three amide herbicides were purified by the semi-preparative column and were used to investigate the enantioselective effects on target Echinochloa crusgalli (lowland rice weeds), and non-target Microcystis aeruginosa, and the yeast transformed with the human TRβ plasmid organisms. The results showed that (i) the R-enantiomers of the three amide herbicides exhibited the strongest activity toward weed inhibition and the lowest toxicity toward non-target organisms; (ii) napropamide was better suited for controlling root growth, while acetochlor and propisochlor were better for leaves control; (iii) herbicides at certain low concentrations (0.01 mg L^(−1) for acetochlor and propisochlor) could be utilized to promote plant growth. These findings encourage the use of R-amide herbicides instead of their racemates to increase the efficiency of weed control and reduce the risk to non-target organisms. On the other hand, the adverse effects are caused mostly by S-enantiomer, using R-enantiomer-enriched products may offer great environmental/ecological benefits
Enantioseparation of four amide herbicide stereoisomers using high-performance liquid chromatography
The chirality of herbicides has been the focus of research. However, there is little information on the enantioseparation of amide herbicides with different chiral elements. In this study, the need for different chiral stationary phases (CSPs), mobile phases, temperatures and flow rates for the separation of napropamide, acetochlor and propisochlor was discussed in detail and compared to metolachlor. Resolution of C-chiral enantiomers was easier than that of axial-chiral enantiomers. Metolachlor and acetochlor could achieve baseline separation only on AY-H and AS-H columns, respectively. Propisochlor had satisfactory separations on OD-H and AS-H columns. Napropamide was separated on OJ-H, AY-H and AS-H columns. Both the structures of the compounds and CSPs and the interactions between them played significant roles in the enantioseparations. Molecule dockings were also used to elucidate the separation mechanisms. C-chiral enantiomers had perfect symmetry in their optical properties, whereas the axial-chiral enantiomers did not. The elution order for napropamide, acetochlor and propisochlor, with a single chiral location, was R- prior to S-. These results were the first that compare the enantioseparations of four amide herbicides with different chirality, and they provided the absolute configurations for the herbicides. The paper also illustrated certain mechanisms for enantioseparations