scholarly journals Macroparticle-enhanced cultivation of Lentzea aerocolonigenes: Variation of mechanical stress and combination with lecithin supplementation for a significantly increased rebeccamycin production

2021 ◽  
Author(s):  
Kathrin Schrinner ◽  
Marcel Schrader ◽  
Jana Niebusch ◽  
Kristin Althof ◽  
Friederike Schwarzer ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Shake Flask ◽  
Systematic Investigation ◽  
Glass Beads ◽  
Antitumor Antibiotic ◽  
Soy Lecithin ◽  
Induced Stress ◽  
Stress Energy ◽  
Bead Diameter ◽  
Different Diameters

The actinomycete Lentzea aerocolonigenes produces the antitumor antibiotic rebeccamycin. In previous studies the rebeccamycin production was significantly increased by the addition of glass beads during cultivation in different diameters between 0.5 – 2 mm and the induced mechanical stress by the glass beads was proposed to be responsible for the increased production. Thus, this study was conducted to be a systematic investigation of different parameters for macroparticle addition, such as bead diameter, concentration and density (glass and ceramic) as well as shaking frequency, for a better understanding of the particle induced stress on L. aerocolonigenes. The induced stress for optimal rebeccamycin production can be estimated by a combination of stress energy and stress frequency. In addition, the macroparticle-enhanced cultivation of L. aerocolonigenes was combined with soy lecithin addition to further increase the rebeccamycin concentration. With 100 g L glass beads in a diameter of 969 µm and 5 g L soy lecithin a concentration of 388 mg L 1 rebeccamycin was reached after 10 days of cultivation, which corresponds to the highest rebeccamycin concentrations achieved in shake flask cultivations of L. aerocolonigenes stated in literature so far.

Variation of Local Mechanical Stress During the Different Processing Steps of Ic-Isolation: a Micro-Raman Spectroscopy Study

1993 ◽  
Vol 308 ◽  
Author(s):  
Ingrid De Wolf ◽  
Herman E. Maes ◽  
Hans Norström
Keyword(s):  
Raman Spectroscopy ◽  
Integrated Circuits ◽  
Mechanical Stress ◽  
Local Variation ◽  
Micro Raman Spectroscopy ◽  
Induced Stress ◽  
Last Stage ◽  
Edge Force ◽  
Field Oxide ◽  
Processing Steps

ABSTRACTLocal mechanical stress introduced in the silicon substrate during the successive steps of poly-buffered local isolation of MOS integrated circuits is studied with micro-Raman spectroscopy. It is shown that the magnitude and the local variation of the stress is highly affected by the different processing steps. After deposition of the nitride mask, the stress can be described as caused by an edge-force. Field oxidation reduces the mask-induced stress but introduces thermal stress from the field oxide. Also the formation of the bird's beak gives rise to additional local tensile stress, especially at the tip of the bird's beak. Removal of the nitride mask results in a partial relaxation: the stress caused by the bird's beak relaxes. In this last stage of the isolation process, the stress image is mostly determined by the field oxide.

scholarly journals Thigmomorphogenic responses of epiphytic bromeliads to mechanically induced stress

Plant Ecology ◽  
2021 ◽  
Author(s):  
Jessica Y. L. Tay ◽  
Gerhard Zotz ◽  
Helena J. R. Einzmann
Keyword(s):  
Mechanical Stress ◽  
Treatment Effects ◽  
Morphological Changes ◽  
Functional Ecology ◽  
Stress Effect ◽  
Vascular Epiphytes ◽  
Induced Stress ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Epiphytic Bromeliads

AbstractVascular epiphytes represent almost 10% of all terrestrial plant diversity. Despite the extensive research on the functional ecology and challenges of epiphytic growth, there is still very little known on how exposure to mechanically induced stress affects the growth and development of epiphytes. Therefore, this study investigated the effect of such mechanical stress on the growth and biomass allocation of epiphytic bromeliads. Juvenile plants of two species were subjected to two types of mechanical stress in the greenhouse—permanent displacement and temporary, recurring mechanical flexing. ANOVAs were used to test possible treatment effects on growth, root–shoot ratio, root diameter, and root area distribution ratio. Contrary to previous studies on herbaceous plants, these bromeliads showed little to no change in root and shoot properties in either species. The root–shoot ratio increased in disturbed Guzmania lingulata plants, but not in Vriesea sp. Treatment effects on growth were inconsistent: a stress effect on growth was significant only in the first 2 months of the experiment in G. lingulata, whilst none of the stress treatments negatively affected growth in Vriesea sp. All disturbed plants showed some degree of curvature on their stems and leaves against the area of stress to obtain an upright position. This was probably related to the maintenance of a functional tank. This study provides quantitative and qualitative data to understand thigmomorphogenic responses of bromeliads to mechanical stress. Future studies could include field surveys to quantify on-site mechanical stresses and the corresponding morphological changes in vascular epiphytes.

scholarly journals A systematic investigation into the effect of fibrillar microstructures on the settlement and attachment strength of the bay barnacle Balanus improvisus under natural conditions

2020 ◽  
Vol 126 (9) ◽  
Author(s):  
Dennis S. Petersen ◽  
Marika Schultz ◽  
Stanislav N. Gorb ◽  
Lars Heepe
Keyword(s):  
Systematic Investigation ◽  
Natural Conditions ◽  
Ship Hulls ◽  
Microstructured Surfaces ◽  
Attachment Strength ◽  
Initial Settlement ◽  
Settlement Ratio ◽  
The Baltic ◽  
Different Diameters ◽  
Density Development

Abstract Barnacles are one of the most prominent hardfouling organisms in the marine environment. They are able to adhere efficiently to nearly every surface underwater including artificial ones like ship hulls and maritime installations. This overgrowing can lead to huge economical costs. Previous studies have shown that specific microstructure types including micropillars can reduce the initial settlement of barnacles. However, it is not clear how adult barnacles are influenced by microstructured surfaces and whether microstructures can even decrease the resulting adhesion strength of them under natural conditions. Therefore, the aim of this study was to systematically investigate the influence of height, diameter, aspect ratio and flexibility of fibrillar microstructures made from polydimethylsiloxane (PDMS) on initial settlement of barnacles as well as the permanent attachment of adult ones. Micropillars with three different heights (50 µm, 100 µm, 200 µm) and two different diameters (25 µm, 50 µm) were exposed to the Baltic Sea for 12 weeks. On a weekly basis, all barnacles (Balanus [= Amphibalanus] improvisus) were tracked individually to calculate the release-to-settlement ratio and to capture the average attachment duration prior to detachment. The results have shown that with increasing height, both initial settlement and fouling density development were reduced. An increase of diameter showed a similar relationship but at a much smaller scale. All tested microstructures decreased the detachment rates of barnacles from the surface compared to a flat PDMS control. However, they appear to complicate the development of a strong adhesive joint in the young adult phase. Some grade of flexibility in the microstructures appeared to increase the fouling retention. The results shed light in the interaction between adult barnacle adhesion and microstructures and may help in the development of new antifouling technologies.

Role of f(G,T) gravity on the evolution of relativistic stars

2018 ◽  
Vol 27 (04) ◽  
pp. 1850044 ◽  
Author(s):  
Muhammad Zaeem-ul-Haq Bhatti ◽  
M. Sharif ◽  
Z. Yousaf ◽  
M. Ilyas
Keyword(s):  
Systematic Investigation ◽  
Compact Stars ◽  
Energy Conditions ◽  
Physical Parameters ◽  
Energy Tensor ◽  
Star Model ◽  
Relativistic Stars ◽  
Star Models ◽  
Stress Energy

The aim of this paper is to explore some physically viable aspects for the possible emergence of compact stars in [Formula: see text] theory of gravity with some particular models, where [Formula: see text] and [Formula: see text] are Gauss–Bonnet invariant and trace of stress–energy tensor, respectively. We present basic formalism of this modified theory in the presence of anisotropic source. We explore some realistic aspects using the energy conditions with physical parameters. Three distinct known star models namely, [Formula: see text] [Formula: see text] and [Formula: see text], are used for this systematic investigation. The physical behavior of anisotropic stresses, energy density, energy conditions, measure of anisotropy and stability of compact stars are discussed through plots. We conclude that compactness at the core of a star model increases and energy conditions hold.

scholarly journals Preplant Application of 1-Methylcyclopropene Improves Postplanting Performance of Tomato Transplants by Suppressing Ethylene-induced Stress Responses

HortScience ◽  
2020 ◽  
Vol 55 (4) ◽  
pp. 581-588
Author(s):  
Shinsuke Agehara
Keyword(s):  
Mechanical Stress ◽  
Stress Responses ◽  
Field Conditions ◽  
Shoot Biomass ◽  
Management Approach ◽  
Flower Number ◽  
Growth Modulation ◽  
Induced Stress ◽  
Transplant Shock ◽  
Marketable Fruit

Transplant shock is caused by various types of abiotic stress, limiting stand establishment and productivity of many vegetable crops. Although postplanting stress can be minimized under well-managed field conditions, mechanical stress is unavoidable during the transport and transplanting of seedlings. Mechanical stress stimulates ethylene production, which in turn, induces overall growth retardation as a stress adaptation strategy. We hypothesized that, under optimum field conditions, transplant shock is caused primarily by ethylene-induced stress responses, and that inhibiting ethylene action can reduce transplant shock by maintaining uninterrupted growth. In this study, a new spray formulation of 1-methylcyclopropene (1-MCP) was used to inhibit ethylene perception in tomato (Solanum lycopersicum L.) seedlings. A bioassay experiment demonstrated reduced ethylene sensitivity in 1-MCP–treated (1 mg·L−1) seedlings using leaf epinasty and chlorosis as measured responses. Field experiments evaluated growth, physiological, and yield responses to preplant spray treatment of 1-MCP (12.5–50 mg·L−1) under optimum field conditions. Postplanting growth modulation by 1-MCP at the flowering stage was characterized by enhanced height growth and suppressed stem diameter growth, indicating the inhibition of ethylene-induced stress responses. At the fruit harvest stage, preplant 1-MCP treatment increased shoot biomass by 23% and flower production by 22%, while improving photosynthetic capacity on a whole-plant basis. As a result, 1-MCP–treated plants produced 13% to 24% higher total marketable fruit yields than untreated plants in two consecutive growing seasons. Correlation analyses revealed that flower number increased proportionally to shoot biomass, and marketable fruit number increased proportionally to flower number. These results support our hypothesis and propose that preplant 1-MCP treatment is a new stress-management approach to reducing transplant shock. Importantly, this new technique is easily implementable by commercial transplant nurseries with no negative side effect on transplant quality and fruit development.

Mechanical-Stress-Controlled Silicide Interconnections for Highly Reliable Semiconductor Devices

2002 ◽  
Vol 716 ◽  
Author(s):  
Hiromi Shimazu ◽  
Hideo Miura
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Mechanical Stress ◽  
Critical Stress ◽  
Critical Thickness ◽  
Titanium Film ◽  
Cross Sectional ◽  
Silicide Film ◽  
Induced Stress ◽  
Observation Results

AbstractMechanical stress develops in silicide interconnection structures due to the volumetric shrinkage of newly grown silicide film during silicidation. Silicidation-induced stress of about 1 GPa was measured by inducing a reaction between a silicon wafer and a titanium film deposited on the wafer. The stress developed near the interface between the grown silicide film. The remaining silicon was analyzed using a finite-element method. The critical stress for delamination at the interface was determined by comparing the results of the estimated stress at the interface with the cross-sectional observation results of different interconnection-structures test samples. We also determined the critical thickness of TiSi2 and the diameter of silicide contacts for eliminating delamination at the interface.

Response to Comment on T. Stauch, A. Dreuw, “Stiff-stilbene photoswitch ruptures bonds not by pulling but by local heating”, Phys. Chem. Chem. Phys., 2016, 18, 15848

2016 ◽  
Vol 18 (38) ◽  
pp. 26994-26997 ◽  
Author(s):  
Tim Stauch ◽  
Andreas Dreuw
Keyword(s):  
Mechanical Stress ◽  
Ring Opening ◽  
Computational Analysis ◽  
Local Heating ◽  
Chem Phys ◽  
Stress Energy ◽  
Phys Chem Chem Phys

Computational analysis of mechanical stress energy revealed that photoisomerization of stiff-stilbene cannot initiate the ring opening of cyclobutene via a purely mechanical pathway.

Geometrie Unification of Classical Gravitational and Electromagnetic Interaction in Five Dimensions: a Modified Approach

1980 ◽  
Vol 35 (3) ◽  
pp. 302-307 ◽  
Author(s):  
Wolfgang W. Osterhage
Keyword(s):  
Field Equation ◽  
Mechanical Stress ◽  
Source Term ◽  
Electromagnetic Interaction ◽  
Proper Time ◽  
Sole Source ◽  
Five Dimensions ◽  
Stress Energy

Abstract A unification of the gravitational with the electromagnetic interaction within a classical framework is proposed. It is based on a V5-geometry, with x5 = q/m. The sole source term is mechanical stress energy, positioned along x5. The trajectories of testbodies are placed in V4 (x5 = const)-slices. The final field equation couples a geometric G-tensor to mechanical stress energy, its momentum with respect to x5 and the change of this momentum with proper time τ.

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