High Stress Resistance Research Articles

Biomechanical analyses of mesh fixation in TAPP and TEP hernia repair

Reliable laparoscopic fixation of meshes prior to their fibrous incorporation is intended to minimize recurrences following transabdominal preperitoneal hernia repair (TAPP) and totally extraperitoneal repair (TEP) repair of inguinal hernias. However, suture-, tack- and staple-based fixation systems are associated with postoperative chronic inguinal pain. Initial fixation with fibrin sealant offers an atraumatic alternative, but there is little data demonstrating directly whether fibrin-based mesh adhesion provides adequate biomechanical stability for repair of inguinal hernia by TAPP and TEP. Using a newly developed, standardized simulation model for abdominal wall hernias, sublay repairs were performed with six different types of commercially available hernia mesh. The biomechanical stability achieved, and the protection afforded by the mesh-hernia overlap, were compared for three different techniques: nonfixation, point-by-point suture fixation, and fibrin sealant fixation. Mesh dislocation from the repaired hernia defect was consistently seen with nonfixation. This was reliably prevented with all six mesh types when fixed using either sutures or fibrin sealant. The highest stress resistance across the whole abdominal wall was found following superficial fixation with fibrin sealant across the mesh types. There was a highly statistically significant improvement in fixation stability with fibrin sealant versus fixation using eight single sutures (p = 0.008), as assessed by the range of achievable peak pressure stress up to 200 mmHg. To ensure long-term freedom from recurrence, intraoperative mesh-hernia overlap must be retained. This can be achieved with fibrin sealant up to the incorporation of the mesh - without trauma and with biomechanical stability.

Physiological and transplanting performance of Quercus ilex L. (holm oak) seedlings grown in nurseries with different winter conditions

Resistance to drought and frost is a requisite for seedling survival and growth in Mediterranean continental areas. Environmental conditions in the nursery influence the functional characteristics of seedlings. We addressed if cultivation in nurseries that experience different winter conditions affected cold hardiness and other functional attributes relevant for transplanting performance of Quercus ilex (holm oak) seedlings. It was hypothesised that plants grown at cold-winter sites have higher stress resistance, vigour, and transplanting performance than the seedlings cultivated in mild-winter sites. We also studied if current root growth activity, determined as the number of white roots on the plug surface, can be used to predict frost hardiness. Seedlings from the same seed lot were cultivated at an inland and a coastal nursery, the former having colder winters than the latter. Cultural practices in both nurseries were similar. On seven dates from mid-summer 2000 to mid-spring 2001, frost damage was assessed by shoot mortality and electrolyte leakage after freezes to either −12 °C or −19 °C. Potential drought tolerance, root growth capacity, plant morphology, shoot nutrient and soluble sugar concentration were determined in late fall and in mid-winter. Seedlings were transplanted at an inland site in late fall and in mid-winter and their survival and growth was measured for 2 years. Coastal plants cold hardened latter in the fall and dehardened earlier in the spring than inland seedlings. In the fall and in early spring, coastal plants had greater frost damage and shoot mortality than inland seedlings at both −12 and −19 °C. In mid-winter, frost damage and shoot mortality after −12 °C did not differ between nurseries but was greater in coastal plants after −19 °C. Inland plants had lower osmotic potential either at full turgor or at the turgor loss point suggesting they were potentially more drought-tolerant. Inland seedlings were bigger, concentrated more shoot N and soluble sugars, and had higher specific leaf mass and root growth capacity than coastal seedlings. Current root growth activity had the same seasonal variation pattern at both locations and did not correlate with frost hardiness. Nursery location did not affect transplanting mortality. However, inland seedlings had greater growth than coastal seedlings when planted in mid-winter planting but not in late fall. This study demonstrates that differences in winter conditions in the nursery have a strong effect on the functional and transplanting performance of Q. ilex seedlings and that current root growth activity cannot be used as a predictor of the frost hardiness in this oak.

115 SLM法を用いて作製した鉄鋼被覆材の耐酸化性(超塑性と材料および造形法)

A powder eutectic coating using Al and Ti powder on Fe substrate is successfully performed by laser scanning method. It is possible to achieve high heat stress resistance and high oxidation resistance without using the pessimistic elements such as Cr, Ni and so on.

Maintaining a healthy SPANC balance through regulatory and mutational adaptation

Stress protection is an important but costly contributor to bacterial survival. Two distinct forms of environmental protection share a common cost and a significant species-wide variability. Porin-mediated outer membrane permeability and the RpoS-controlled general stress response both involve a trade-off between self-preservation and nutritional competence, called the SPANC balance. Interestingly, different Escherichia coli strains exhibit distinct settings of the SPANC balance. It is tilted towards high stress resistance and a restricted diet in some isolates whereas others have broader nutritional capability and better nutrient affinity but lower levels of resistance. Growth- or stress-related selective pressures working in opposite directions (antagonistic pleiotropy) result in polymorphisms affecting porins and RpoS. Consequently, these important cellular components are present at distinct concentrations in different isolates. A generalized hypothesis to explain bacterial adaptation, based on the SPANC investigations, is offered. A holistic approach to bacterial adaptation, involving a gamut of regulation and mutation, is likely to be the norm in broadening the capabilities of a species. Indeed, there is unlikely to be a standard regulatory setting typical for all members of a species. Gene regulation provides a limited fine control for maintaining the right level of adaptation in a particular niche but mutational changes provide the coarse control for adaptation between the species-wide environments of free-living bacteria.

A polyhydroxybutyrate-producing Pseudomonas sp. isolated from Antarctic environments with high stress resistance.

Pseudomonas sp. 14-3, a strain that accumulates large quantities of polyhydroxybutyrate (PHB) when grown on octanoate, was isolated from Antarctic environments. This isolate was characterized on the basis of phenotypic features and partial sequencing of its 16S ribosomal RNA gene. Pseudomonas sp. 14-3 showed increased tolerance to both thermal and oxidative stress compared with three other Pseudomonas species. Stress tolerance of Pseudomonas sp. 14-3 was analyzed in polyhydroxyalkanoate accumulating and non-accumulating conditions, and increased levels of stress resistance were observed when PHB was produced. Pseudomonas sp. 14-3 was isolated from Antarctic regions, a habitat normally exposed to extreme conditions. An association between high PHB accumulation and high stress resistance in bacteria adapted to extreme environments is suggested.

Immunocompetence of fattening pigs fed organic versus conventional diets in organic versus conventional housing

The effect of organic or conventional feeding on the immune response of pigs was determined using organic or conventional housing in a pig fattening unit. The experimental design involved four pens of four animals per housing and diet combination (organic housing and organic nutrition; organic housing and conventional nutrition; conventional housing and organic nutrition and conventional housing and conventional nutrition). The IgM, IgA and IgG responses against intramuscularly injected bovine thyroglobulin were determined as indicators of the antigen-specific immune responsiveness. Some general health and welfare related parameters were evaluated by measuring haptoglobin concentrations at selected times; blood lactate concentration was measured at slaughter. Conventional housing led to a higher IgG response three weeks after the first immunisation. Organic housing led to lower haptoglobin and lactate concentrations at slaughter, indicating a higher stress resistance in these pigs. No major differences between the two feeding types were found. We conclude that the immune responses following either a conventional or an organic diet are comparable, whereas organic housing can increase stress resistance at slaughter compared to conventional housing.

The high general stress resistance of the Saccharomyces cerevisiae fil1 adenylate cyclase mutant (Cyr1Lys1682) is only partially dependent on trehalose, Hsp104 and overexpression of Msn2/4-regulated genes.

The initiation of fermentation in the yeast Saccharomyces cerevisiae is associated with a rapid drop in general stress resistance. Previously we identified a mutant which is deficient in fermentation-induced loss of stress resistance (fil1), as a partially inactivating mutant in adenylate cyclase. We have now investigated possible causes of its high stress resistance. Deletion of the TPS1 gene, encoding the first enzyme in the biosynthesis of trehalose, or the heat shock protein gene HSP104 only resulted in a minor effect on heat stress resistance compared with deletion of these genes in a wild-type background. A strain with a deletion of both genes still showed a higher stress resistance in the fil1 background compared to the corresponding wild-type background. Deletion of the transcription factor genes MSN2 and MSN4, which are required for the expression of STRE-regulated genes, resulted in a dramatic drop in heat resistance in the wild-type background but had much less effect in the fil1 mutant. The fil1 msn2Deltamsn4Delta strain remained more heat-resistant than a wild-type strain. A strain in which all four genes, TPS1, HSP104, MSN2 and MSN4, are deleted was very sensitive to heat stress and also to oxidative and salt stress. Presence of the fil1 mutation in such a strain, however, still clearly enhanced heat, oxidative and salt stress resistance. These results indicate that, in addition to trehalose, Hsp104 and the Msn2/4-controlled genes, other factors exist in S. cerevisiae that can, significantly and independently of the known factors, enhance general stress resistance. The mutants described in this work provide a tool to identify these novel components.

Photosynthesis and photoprotection in Nicotiana tabacumL. in vitro-grown plantlets

Nicotiana tabacum L. plantlets were cultured in vitro photoautotrophically (0% sucrose) and photomixotrophically (3% or 5% sucrose) at two irradiances (80 or 380 mumol m-2 s-1) with the aim of investigating the effect of these culture conditions on photosynthetic parameters and on protective systems against excess excitation energy. In plantlets grown photoautotrophically under higher irradiance photoinhibition was demonstrated. These plantlets had a decreased chlorophyll (Chl) a + b content and Chl a/b ratio, an increased content of xanthrophyll cycle pigments and a higher deepoxidation state, a decreased maximum photochemical efficiency of photosystem II (PS II) and actual photochemical efficiency of PS II, and an increased non-photochemical quenching. In the photoautotrophically grown plantlets and those photomixotrophically grown with 3% sucrose, the increase of growth irradiance from 80 to 380 mumol m-2 s-1 stimulated the activities of ascorbate-glutathione cycle enzymes with the exception of ascorbate peroxidase. Ascorbate peroxidase activity was not affected by the increase in growth irradiance but a significant decrease with increasing sucrose concentration was evident. The higher concentration of sucrose in the medium (5%) in combination with the higher irradiance inhibited photosynthesis (decrease in Chl a + b content and net photosynthetic rate) but no significant changes in activities of ascorbate-glutathione cycle enzymes were found. These results suggest that exogenous sucrose added to the medium improved high irradiance and oxidative stress resistance of the plantlets but the effect of sucrose is concentration dependent.

Properties of titanium dioxide films prepared by reactive electron-beam evaporation from various starting materials.

There is a wide choice of starting materials for the production of titanium dioxide films by reactive electron-beam evaporation. We have investigated the specific merits of these materials in terms of refractive index, stress, and abrasion resistance of the resultant titanium dioxide films. The suboxides TiO, Ti2O3, and Ti3O5 as well as titanium dioxide and titanium metal were reactively evaporated, and titanium dioxide films free of absorption were obtained on substrates at 25 and 250 degrees C. On unheated substrates the refractive index, which varies from 2.06 to 2.22, the stress, and the abrasion resistance all depend on the starting material used. On substrates heated to 250 degrees C the refractive indices of all films lie closely about 2.4, and all films show high tensile stress and good abrasion resistance.

Pre-Treatment of Bean Seedlings with Choline Compounds Increases the Resistance of Photosynthetic Apparatus to UV-B Radiation and Elevated Temperatures

Bean (Phaseolus vulgaris L. cv. Berbukskaya) seedlings were pre-treated with choline compounds, 19 mM 2-ethyltrimethylammonium chloride (Ch) or 1.6 mM 2-chloroethyltrimethylammonium chloride (CCh), during 24 h, then after 6 d the excised primary leaves were exposed to UV-B and high temperature stress. Chlorophyll (Chl) fluorescence, delayed light emission, accumulation of photosynthetic pigments, contents of thiobarbituric acid reactive substances, and activities of the active oxygen detoxifying enzymes (superoxide dismutase, ascorbate peroxidase, and glutathione reductase) were examined. Pre-treatment of plants with Ch or CCh enhanced the resistance of photosystem 2 (PS2) photochemistry to UV-B and heat injuries. The higher stress resistance can be explained by the increased activity of the detoxifying enzymes. The increased content of UV-B-absorbing pigments may also contribute to the enhanced resistance of choline-treated plants to UV-B radiation.

Proposed dates for lifting Sitka spruce planting stock for fresh planting or cold storage, based on physiological indicators

The relationship between physiological status and theability to withstand the stresses of lifting, coldstoring and planting was evaluated from 1992–1995 inSitka spruce (Picea sitchensis (Bong.) Carr.)2 + 1 transplants of Washington/northern Oregon originsgrowing in Ireland. Needle primordium initiationcontinued until later and cold hardiness developedmore slowly in the mild lifting season of 1994/95. The seasonal decline in shoot mitotic activity wasgenerally similar each year, with apices becominginactive in December. Cell divisions in roots ceasedin November or December. Shoots began to deharden inearly February each year, but the rates of dehardeningwere slow until March. Cell divisions in root apicesresumed in February each year, compared with March forshoot apices. The vitality of the seedlings followingcold storage was high for most lift dates except theOctober and April dates. The period of highest stressresistance (as indicated by cold hardiness levels) forlifting for immediate planting was from about lateNovember/early December to early March; shoots werecold hardy to about −20 °C (LT50) at thistime. Seedlings could be lifted and cold stored (1–2 °C)until May/June when shoots were cold hardyto about −30 °C or lower, which coincided withthe period from mid- to late December until March.

Deletion of SFI1, a novel suppressor of partial Ras-cAMP pathway deficiency in the yeast Saccharomyces cerevisiae, causes G(2) arrest.

When glucose is added to Saccharomyces cerevisiae cells grown into stationary phase or on non-fermentable carbon sources a rapid loss of heat stress resistance occurs. Mutants that retain high stress resistance after addition of glucose are called 'fil', for deficient in fermentation induced loss of stress resistance. Transformation of the fil1 mutant, which harbours a point mutation in adenylate cyclase, with a yeast gene library on a single copy plasmid resulted in transformants that were again stress-sensitive. One of the genes isolated in this way was a gene of previously unknown function. We have called it SFI1, for suppressor of fil1. SFI1 is an essential gene. Combination of Sfi1 and cAMP pathway mutations indicates that Sfi1 itself is not involved in the cAMP pathway. Conditional sfi1 mutants did not show enhanced heat resistance under the restrictive condition, whereas overexpression of SFI1 rendered cells heat-sensitive. Sfi1 may be a downstream target of the protein kinase A pathway, but its precise relationship with heat resistance remains unclear. Further analysis showed that Sfi1 is required for cell cycle progression, more specifically for progression through G(2)-M transition. Cells expressing SFI1 under the control of a galactose-inducible promoter arrest after addition of glucose as doublets of undivided mother and daughter cells. These doublets contain a single nucleus and lack mitotic spindles. Sfi1 shares homology with Xenopus laevis XCAP-C, a protein required for chromosome assembly. The conserved residues between these two proteins show a strong bias for charged amino acids. Hence, Sfi1 might be required for correct mitotic spindle assembly and its precise role might be in chromosome condensation. In conclusion, we have identified an essential function in the G(2)-M transition of the cell cycle for a yeast gene of previously unknown function.

Co-extruded seamless tubing has higher stress resistance

Co-extruded seamless tubing has higher stress resistance

Wheat Cultivar Differences in Photosynthetic Response to Low Soil Water Potentials. I. Maintenance of photosynthesis and leaf water potential.

Although many studies have shown cultivar differences in photosynthetic response to water deficit, the understanding of detailed mechanisms is not sufficient. We examined the mechanisms of water stress-resistance in terms of photosynthetic performance under low soil water potential (Ψsoil) with sixteen cultivars of wheat (Triticum aestivum L.) from different habitats, which had shown different drought resistance on a grain yield basis. Cultivar differences in photosynthetic maintenance in response to decrease of Ψsoil (water stress resistance), were found at ail seedling, booting, and grain filling stages. Cultivars with high drought resistance based on grain yield also showed high water stress resistance in photosynthetic performance. Water stress resistance (Rws) was caused more by tolerance (Tws, maintenance ability of photosynthesis in response to decrease of leaf water potential, ΨL)in some cultivars, which maintained relatively high photosynthesis (PN) in spite of decreases in ΨL, while it was caused more by water stress avoidance (Aws, maintenance ability of ΨL in response to decreases in Ψsoil) in other cultivars, which showed a relatively high PN by maintaining a relatively high ΨL under the same low Ψsoil. However, there was a positive correlation between Rws and Tws or between Rws and Aws. It is suggested that avoidance and tolerance usually occur simultaneously in adaptation to low Ψsoil, although water stress resistant cultivars varied in the water stress resistance mechanism.

Differential importance of trehalose in stress resistance in fermenting and nonfermenting Saccharomyces cerevisiae cells.

The trehalose content in laboratory and industrial baker's yeast is widely believed to be a major determinant of stress resistance. Fresh and dried baker's yeast is cultured to obtain a trehalose content of more than 10% of the dry weight. Initiation of fermentation, e.g., during dough preparation, is associated with a rapid loss of stress resistance and a rapid mobilization of trehalose. Using specific Saccharomyces cerevisiae mutants affected in trehalose metabolism, we confirm the correlation between trehalose content and stress resistance but only in the absence of fermentation. We demonstrate that both phenomena can be dissociated clearly once the cells initiate fermentation. This was accomplished both for cells with moderate trehalose levels grown under laboratory conditions and for cells with trehalose contents higher than 10% obtained under pilot-scale conditions. Retention of a high trehalose level during fermentation also does not prevent the loss of fermentation capacity during preparation of frozen doughs. Although higher trehalose levels are always correlated with higher stress resistance before the addition of fermentable sugar, our results show that the initiation of fermentation causes the disappearance of any other factor(s) required for the maintenance of stress resistance, even in the presence of a high trehalose content.

The relationship of Bi/Polar personality patterns with self‐esteem, stress, and satisfaction in dental school

The Bi/Polar Inventory of Core Strength was administered to two senior dental classes. This inventory identifies preferences on three fundamental underlying dimensions of personality and yields eight personality patterns, which were subsequently correlated with the students' self-assessment of various aspects of the dental school experience. Individuals with preferences for risking, practical thinking, and independence consistently demonstrated higher self-esteem, higher ability to cope with the stresses of dental school, lower psychological distress in dental school, and higher satisfaction with dentistry than individuals with polar opposite preferences--thinking, theoretical thinking, and dependence--although only some of these comparisons reached statistical significance. Pattern III (thinking-theoretical-dependent) reported the lowest self-esteem, lowest ability to cope with stress, highest psychological distress, and lowest satisfaction with dentistry. Pattern III may represent a psychological profile exhibiting early warning signs of a potential tension with the task demands of clinical dentistry. Conversely, Pattern VII (risking-practical-independent) may represent a profile prone to high self-esteem, high-stress resistance, low psychological distress, and reasonably high satisfaction with dentistry.

Transplanting Stress in Bareroot Conifer Seedlings: Its Development and Progression to Establishment

Abstract Transplanting stress is: (1) a temporary condition of distress from injuries, depletion, and impaired functions; (2) a process of recovery; and (3) a period of adjustment to a new environment. Some transplanting stress is unavoidable, even with good stock in a favorable environment. The degree and duration of stress depend on the interactions of seedling performance potential and the site environment. Renewal of root-to-soil contact is important for resumption of adequate water and nutrient uptake. Root growth is sensitive to soil temperature and plant moisture stress. If reserve carbohydrates are exhausted before they are replenished from photosynthesis, the seedlings may die. Preplant handling and postplant drought aggravate transplanting stress. Stress can be minimized by planting stock with high stress resistance, preserving seedling performance potential, preparing a favorable planting site environment, and planting the seedlings properly. North. J. Appl. For. 6:99-107, September 1989

ADAPTABILITY INDICATORS OF WINTER TRITICALE VARIETIES IN REINFORCEMENT CONDITIONS OF ARID CLIMATE ON NORTH WEST OF ROSTOV REGION

The average annual temperature over the past 40 years has increased by 2.5°С, over the past decade by 3.4°С. There was a redistribution of precipitation over time, their amount increased in the autumn-winter period and decreased in the spring-summer. The change in the aridity index from 2.65 (long-term average) to 1.72 in the last decade testifies to the increase in the aridity of the climate. For the period 1981-2021. in 7 cases, the autumn vegetation proceeded under favorable conditions, spring-summer in 4. In other years, it proceeded under conditions of varying degrees of aridity. Previous studies have shown that winter triticale exceeds winter wheat in terms of grain yield, on average over decades, by more than 1 t/ha. Therefore, in terms of overcoming the negatives of aridization, triticale has more advantages than winter wheat. In order to develop this paradigm, a study was made of the adaptive properties of 12 winter varieties of triticale, created at different times, in comparison with the standard variety Kapriz. The maximum yield was formed by the variety Argus (2016 - 12.58 t/ha). On average, over the years of study, the Ataman Platov variety was the leader for two predecessors (8.04 t/ha). High stress resistance was found in the Hector variety (SC -5.57), along with this, the variety is characterized by a high level of general and specific adaptive ability, adapted to a wide range of environmental conditions. Varieties Donslav, Ataman Platov, Ramses, Priam and Argus are demanding on environmental conditions. Varieties Hector and Blues react poorly to worsening growing conditions and have advantages in adverse conditions and low agricultural backgrounds. The variation in productivity depending on the year and the predecessor was significant for all varieties. An integral indicator reflecting the productivity and adaptability of a variety is the breeding value of the genotype. According to this indicator, the varieties Ata-man Platov, Hektor, Forte (4.22; 4.31; 4.04) stand out, the highest was in the variety Aznavour (4.44). These genotypes combine high productivity with a stable yield. When cultivating them (and they are approved for sowing in different regions of Russia), it is recommended to pay attention to their biological characteristics. Key words: triticale, cultivar, productivity, adaptability, increased aridity.