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Classic theory on the evolution of anisogamy focuses on the trade-off between gamete productivity and provisioning and mechanisms associated with post-zygotic survival. In this article, the role of mortality acting on both zygotes and gametes is explored as a factor influencing the evolution of different sized gametes. In particular, variable mortality through differential survival or metabolic damage is shown to affect the persistence of isogamy, the evolution of more than two sexes and the evolution of anisogamy. Evolutionary stable isogamous states are shown to be locally unstable and disruptive selection can induce the evolution of anisogamy. Analysis of both the isogamous and anisogamous ESS points reveals that the persistence of either of these conditions is not always assured. The implications of variable survival on the evolution of anisogamy are discussed.

The study examined the temporal response of Hyalella azteca to pentachlorobenzene (PCBZ) in water-only exposures. Toxicity was evaluated by calculating the body residue of PCBZ associated with survival. The concentration of PCBZ in the tissues of H. azteca associated with 50% mortality decreased from 3 to 0.5 micromol/g over the temporal range of 1 to 28 d, respectively. No significant difference was observed in the body residue calculated for 50% mortality when the value was determined using live or dead organisms. Metabolism of PCBZ was not responsible for the temporal response because no detectable PCBZ biotransformation occurred over an exposure period of 10 d. A damage assessment model was used to evaluate the impact and repair of damage by PCBZ on H. azteca. The toxicokinetics were determined so that the temporal toxicity data could be fit to a damage assessment model. The half-life calculated for the elimination of PCBZ averaged approximately 49 h, while the value determined for the half-life of damage repair from the damage assessment model was 33 h.

Ionizing radiation produces both singly and multiply damaged DNA sites. Multiply damaged sites (MDS) have been implicated in radiation-induced cell killing and mutagenesis. The spatial distribution of elementary damages (strand breaks and base damages) that constitute MDS is of special interest, since the complexity of MDS has an impact on damage repair. A fast and easy-to-implement algorithm to simulate the local clustering of elementary damages produced by ionizing radiation is proposed. This algorithm captures the major trends in the DNA damage spectrum predicted using detailed track- structure simulations. An attractive feature of the proposed algorithm is that only four adjustable parameters need to be identified to simulate the formation of DNA damage. A convenient recipe to determine the parameters used in the fast Monte Carlo damage simulation algorithm is provided for selected low- and high-LET radiations. The good agreement among the damage yields predicted by the fast and detailed damage formation algorithms suggests that the small-scale spatial distribution of damage sites is determined primarily by independent and purely stochastic events and processes.

A new microemulsion additive has been developed that is effective in remediating damaged wells and is highly effective in fluid recovery and relative permeability enhancement when applied in drilling and stimulation treatments at dilute concentrations. The microemulsion is a unique blend of biodegradable solvent, surfactant, co-solvent and water. The nanometer-sized structures are modeled after Veronoi structures which when dispersed in the base treating fluid of water or oil permit a greater ease of entry into a damaged area of the reservoir or fracture system. The structures maximize surface energy interaction by expanding to twelve times their individual surface areas to allow maximum contact efficiency at low concentrations (0.1–0.5%). Higher loadings on the order of 2% can be applied in the removal of water blocks and polymer damage. Lab data are shown for the microemulsion in speeding the cleanup of injected fluids in tight gas cores. Further tests show that the microemulsion additive results in lower pressures to displace frac fluids from propped fractures resulting in lower damage and higher production rates. This reduced pressure is also evident in pumping operations where friction is lowered by 10–15% when the microemulsion is added to fracturing fluids. Field examples are shown for remediation and fracture treating of coals, shales and sandstone reservoirs, where productivity is increased by 20–50% depending on the treatment parameters. Drilling examples are shown in horizontal drilling where wells cleanup without the aid of workover rigs where offsets typically require weeks of workover.

This paper briefly discusses some of the external forces that act upon a typical distribution system. These forces can cause damage, either immediately or over long periods of time, which in turn affect the systems reliability and integrity. This paper examines methods in repairing conductor damage and protection measures that can be implemented to establish a higher level of system reliability. Because higher stresses occur at the support locations where the cable is constrained, this paper concentrates on damage repair in these areas.

This paper is concerned with the theoretical prediction of stress fractures in the bones of athletes, soldiers and others during periods of intensive exercise. Previously [J. Orthop. Res. 19 (2001) 919] we showed that test data on the fatigue strength of bone in vitro could be described using Weibull's probabilistic model, allowing predictions to be made of the probability of failure as a function of time under cyclic loading. This paper extends the earlier argument by including two living processes which act to reduce the incidence of failure: (i) repair of damage, and; (ii) adaptation by bone deposition. Having incorporated these aspects into the mathematical model, we applied the theory to a specific case: the human second metatarsal. We predicted a 17% incidence of stress fractures, all occurring within 6 weeks of commencement of the training programme. These predictions agreed well with clinical findings. Interestingly, we concluded that the major effect in preventing stress fractures comes from repair rather than from adaptation, which has a relatively minor role because it acts more slowly.

The armored family of vehicles (AFV) is a US Army program to design and field the next generation of armored tracked vehicles as a single system. Encompassing twenty-six different vehicle configurations, the AFV places special emphasis on commonality in the design. It is currently in the concept definition phase. Work which examines the impact that component commonality has on battle damage repair is reported. >

The improvised repair of battle damage to military equipment on the battlefield is a vital part of a repair strategy and one that can win battles. Such battle damage repair (BDR), although improvised, should be carefully planned for, and technicians must be schooled and trained in the special techniques required. While much can be done on the battlefield, BDR can be considerably enhanced during the design phase, where an awareness of the problem can do much to influence equipment design. One such approach to BDR is described, along with a training philosophy. Background experience drawn from operations in World War II and the Falklands campaign, and typical examples of repairs and their influence on design are given. >

In 1995, a large structural restoration of two coral reef grounding sites was implemented in the Florida Keys National Marine Sanctuary. The partnership of NOAA, the U.S. Army Corps of Engineers, and private industry engineers, surveyors, and marine constructors made the restoration effort possible. Many unique designs and practice were utilized in the project.

It is well admitted that the mechanical loading plays an important role in the growth and maintenance of our skeleton, and that microdamage (i.e.: microcracks) occurs naturally when the bone is overloaded during day-to-day activities. It is also argued, from experimental and theoretical viewpoint, that the cells which built and rebuilt the skeleton are sensitive for both strain and microdamage. The recent damage-bone remodeling theory is employed here to study the mechanical response of the three unit-bone bars that simulate bone trabeculae in the form of truss. It is shown that under constant load, such a structure exhibit inhomogeneous strain and it's response to external applied load depends strongly upon the manner in which the microdamage is distributed.

To investigate the extent of non-homologous end-joining (NHEJ) in the mechanism of cisplatin radiosensitization.Ku80-deficient cells are deficient in the non-homologous DNA double-strand break repair process, while the wild-type MEF cells maintain full mammalian cell repair capabilities. Both cell lines were exposed to clinically applicable doses of cisplatin (1, 3 and 6 microg x ml(-1)) for 1 h immediately before exposure to 250 kV X-rays. Radiation responses were plotted for each cell line and for all doses of cisplatin to observe relative levels of radiosensitization. Split-dose experiments were also performed on each cell line to measure levels of sublethal damage repair.Radiosensitization was observed in the wild-type cells but not in the Ku80 cells when treated with a combination of 1 microg x ml(-1) cisplatin followed by X-rays, implying that the NHEJ pathway may play a large role in cisplatin radiosensitization. Concurrent administration of this cisplatin dose with radiation produced similar levels of radiosensitization. Conversely, 3 and 6 microg x ml(-1) cisplatin applied immediately before radiation revealed an increasing resistance to radiation in both cell lines--possibly due to resistant subpopulations of cells remaining after subsequent lethal doses of cisplatin. Further experiments revealed that the high concentrations of cisplatin did not alter cell cycle distribution. Finally, split-dose experiments revealed that the NHEJ pathway also plays a significant role in sublethal damage repair.The study reveals that clinically applicable doses of cisplatin treatment results in the radiosensitization of mammalian cells due to the inhibition of the operation of NHEJ.

This bibliography is published by the Joint Technical Coordinating Group on Aircraft Survivability (JTCG/AS) Central Office. The Joint Aeronautical Commanders Group (JACG) chartered the JTCG/AS. The JTCG/AS organization is depicted on page 3. The purpose of this document is to provide a listing of technical reports, which have been published under the auspices of the JTCG/AS. This bibliography contains abstracts which are organized by date of publication for publications produced by the three principal subgroups; Susceptibility Reduction, Vulnerability Reduction, and Survivability Methodology. Administrative support publications, aircraft battle damage repair publications and publications pertaining to aircraft survivability but not funded by the JTCG/AS are also included. An index for each of these areas is provided following the collection of abstracts.

A radiobiological model for closely spaced non-instantaneous radiation fractions is presented, based on the premise that the time process of sublethal damage (SLD) repair is 'reciprocal-time' (second order), rather than exponential (first order), in form. The initial clinical implications of such an incomplete-repair model are assessed. A previously derived linear-quadratic-based model was revised to take account of the possibility that SLD may repair with time such that the fraction of an element of initial damage remaining at time t is given as 1/(1 + zt), where z is an appropriate rate constant; z is the reciprocal of the first half-time (tau) of repair. The general equation so derived for incomplete repair is applicable to all types of radiotherapy delivered at high, low and medium dose-rate in fractions delivered at regular time intervals. The model allows both the fraction duration and interfraction intervals to vary between zero and infinity. For any given value of z, reciprocal repair is associated with an apparent 'slowing-down' in the SLD repair rate as treatment proceeds. The instantaneous repair rates are not directly governed by total dose or dose per fraction, but are influenced by the treatment duration and individual fraction duration. Instantaneous repair rates of SLD appear to be slower towards the end of a continuous treatment, and are also slower following 'long' fractions than they are following 'short' fractions. The new model, with its single repair-rate parameter, is shown to be capable of providing a degree of quantitative explanation for some enigmas that have been encountered in clinical studies. A single-component reciprocal repair process provides an alternative explanation for the apparent existence of a range of repair rates in human tissues, and which have hitherto been explained by postulating the existence of a multi-exponential repair process. The build-up of SLD over extended treatments is greater than would be inferred using a single-exponential repair model and this has important implications in several areas of radiotherapy.

United States Air Force (USAF) Aircraft Battle Damage Repair (ABDR) strategies, techniques and technologies are directly applicable to NASA efforts to develop on-orbit repair capabilities for the International Space Station (ISS). At the operational level, USAF repair strategies developed since the Vietnam War stressed the need for methodical damage assessment, categorization, and repair. This approach should be adopted for future repair operations onboard the ISS. At the technical level, repairs based upon material ultimate properties, preparation for damage to multiple systems and specialized damage effects have shaped ABDR techniques to provide flexible repair strategies for Air Force aircraft. These techniques should also be considered when developing ISS repair strategies. Overall, a baseline for comparison between ISS repair and ABDR clearly demonstrates the need for further technical interchange. Lessons learned from ABDR experiences with provide early insight into techniques and strategies proposed for on-orbit ISS repair operations.

Zweischaliges Sichtmauerwerk ist in Norddeutschland eine traditionelle Wandkonstruktion und hat sich dort vor allem bei starker Schlagregenbeanspruchung bewaehrt: Die Vormauerschale uebernimmt den Regenschutz und die Hintermauerschale die konstruktiv-tragende und daemmende Funktion, letzteres meist in Verbindung mit einer zusaetzlichen Waermedaemmung in der Zwischenschicht. Wird die Vormauerschale aber verputzt, dann koennen Putzrisse auftreten, die den Regnschutz und das Aussehen beeintraechtigen. Dies wird anhand von zwei Schadensfaellen erlaeutert.

Abstract Studies have indicated resources of 4.6 trillion barrels of heavy oil, and some have expressed a need of novel methods to recover some of this oil. Thermal methods were the vogue twenty years ago, with only one method, steam injection, surviving to a significant extent. This paper describes economic uses of hydrogen peroxide, which is similar to steam injection but with some advantages. Hydrogen peroxide can generate 100% quality steam insitu in concentrations above 25–30%. Lesser concentrations can generate or propagate steam banks and hot water banks. Two uses of hydrogen peroxide are economic-short term stimulation in selected reservoirs, and formation damage repair. Other uses involving heat bank flooding await cost reductions that may occur due to more use and technical advances in the manufacture of hydrogen peroxide. Introduction Hydrogen peroxide is a relatively stable combination of hydrogen and oxygen, made by a chemical process discovered 50 years ago. Physical properties are listed in Table 1. A small amount of hydrogen is required to manufacture 50% concentration, i.e, about 3% by weight. The main uses of hydrogen peroxide are in chemical processes and paper manufacture. Hydrogen peroxide can be decomposed very rapidly over a platinum screen giving off heat, oxygen, and water. Thus if hydrogen peroxide is injected into a reservoir sand, it will decompose slowly giving off heat and oxygen, then the oxygen will react with residual oil to generate more heat and carbon dioxide. Decomposition is exponential with temperature and pH increase. This process has been reported on in a paper by Moss, et. al. Thirty per cent concentration will generate 1200 BTU/lb (100%+ quality steam) with about 1/3 of the heat coming from decomposition and 2/3 coming from reaction with oil. Thus hydrogen peroxide can be used in a variety of ways to recover oil. In addition it is well known that steam stimulation can result in formation clean-up in the vicinity of the well. Thus 50% hydrogen peroxide can generate up to 2000 F. which can repair formation damage. Economic uses Stimulation. Injection of hydrogen peroxide can be economic if the heat is kept near the well-bore. The heat content of a barrel of 50% peroxide can heat up to 48 barrels of oil to 100 F. above the reservoir temperature. Thus small treatments can be effective if allowing a long soak time to moderate the temperature. A study by Niko and Troost has shown that near well bore heating is effective in depletion reservoirs. Oil recovery was independent of soak time and small slugs were superior for early production. The paper by Briggs, et.al. shows that production from steam stimulation in gravity drainage reservoirs does not decline with each successive cycle as much as massive treatments do in other reservoirs. Thus small treatments will be more effective in heat utilization than massive treatments where much of the oil is forced away from the well, and much of the heat injected is lost. Formation Damage Repair. As mentioned previously, steam stimulation can clean up a well. This may be due to wax and asphalt deposits being melted. In addition to these effects, 50% peroxide can generate up to 2000 F. a foot or so away from the well. Thus after treatment, heat conduction will treat the entire well bore vicinity to at least 1000 F. This temperature can cause clay to shrink, destroy carbonates, and vaporize emulsions. Peroxide treatment can be more effective than other treatments such as with acids and solvents, since these liquids can finger through. Peroxide decomposition causes a finger resistant foam of oxygen bubbles in hot water, and heat conduction to untreated areas gives 100% zonal coverage. Gas wells can be treated with pre-injection of a fuel oil. Flooding with Hydrogen Peroxide As with steam, a variety of heat floods can be achieved with hydrogen peroxide. P. 117^

The accumulation of bone microdamage has been proposed as one factor that contributes to increased skeletal fragility with age and that may increase the risk for fracture in older women. This paper reviews the current status and understanding of microdamage physiology and its importance to skeletal fragility. Several questions are addressed: Does microdamage exist in vivo in bone? If it does, does it impair bone quality? Does microdamage accumulate with age, and is the accumulation of damage with age sufficient to cause a fracture? The nature of the damage repair mechanism is reviewed, and it is proposed that osteoporotic fracture may be a consequence of a positive feedback between damage accumulation and the increased remodeling space associated with repair.

Purpose At present, the linear-quadratic model for cellular response to radiation can incorporate sublethal damage repair and repopulation. We suggest an extension, termed LQR, to include also the other two "Rs" of radiobiology, cell cycle redistribution, and reoxygenation. Methods and materials In this approach, redistribution and reoxygenation are both regarded as aspects of a single phenomenon, which we term resensitization. After the first portion of a radiation exposure has decreased the average radiosensitivity of a diverse cell population by preferentially sparing less sensitive cells, resensitization gradually restores the average sensitivity of the population towards its previous value. The proposed LQR formula is of the same form as the original LQ formula, but with two extra parameters, an overall resensitization magnitude and a characteristic resensitization time. The LQR model assumes that resensitization is monotonic rather than oscillatory in time, i.e., always tends to increase average cellular sensitivity as overall time increases. We argue that this monotonicity assumption is likely to hold in clinical situations, though a possible extension is discussed to account for oscillatory decay of resensitization effects. Results The LQR model gives reasonable fits to relevant experimental data in the literature, reproducing an initial rise in cell survival, due to repair, as the treatment time is increased, followed by a resensitization-related decrease in survival due to redistribution and/or reoxygenation for treatment times of the order of the cell cycle time, and a final survival increase due to repopulation as the treatment time is increased still further. Conclusion The LQR model is a simple and potentially useful extension of the LQ model for computing more realistic isoeffect relations for early responding tissues, including tumors, when comparing different radiotherapeutic protocols.

Nature Reviews Molecular Cell Biology 13, 659–671 (2012) In the above article, the sentence “This study was the first to identify a protein (YB1) involved in mitochondrial MMR” incorrectly appeared below reference 107 instead of below reference 103 (de Souza-Pinto, N. C. et al. Novel DNA mismatch-repair activity involving YB-1 in human mitochondria.

This study identifies a new way to maintain telomere integrity involving nucleostemin. Loss of nucleostemin increased the formation of telomere damage foci, and in telomerase-inactive cells (which instead use alternative lengthening of telomeres (ALT)), it decreased the number of ALT-associated PML bodies (APBs; which may have a role in damage repair by homologous recombination (HR)) and the percentage of telomeres associated with APBs. So how does nucleostemin protect telomeres? In ALT cells, nucleostemin increased the sumoylation of the telomere protein TRF1 (which is required for APB formation) and promoted its association with the PML body protein PML-IV. Furthermore, the sumoylated TRF1–PML-IV interaction was induced following DNA damage in a nucleostemin-dependent manner, and this was required for the recruitment of the HR protein RAD51 to damage sites. Importantly, this mechanism was conserved in telomerase-active cells.

Purpose: It is likely that early-responding tissues, such as tumors, repair sublethal damage more rapidly than do late-responding tissues. This difference can be exploited to design protocols with a significantly improved therapeutic advantage for accelerated radiotherapeutic regimens, including brachytherapy. Methods and Materials: The time course of potential protocols is computer optimized, maximizing the therapeutic difference between tumor-control probability ( TCP ), and normal-tissue complication probability ( NTCP ). These quantities are evaluated with the linear-quadratic model, using clinically derived parameters. The optimization is performed by individually adjusting doses in different parts of the treatment, maximizing the therapeutic advantage. In the main calculations, half times for damage repair were T12(late) = 4 h, T12(early) = 0.5 h. Two component (fast/slow) repair processes were also investigated. Results: Protocols determined by optimization have significantly greater therapeutic advantage than continuous low-dose rate ( CLDR ) protocols of the same overall dose and time. The optimized protocols are either (a) acute-dose/gap/ CLDR /gap/acute-dose; or (b) a series of acute doses separated by 3–4 h. As a typical example, results are given for 60 Gy/120 h CLDR brachytherapy, which is assumed to give NTCP = 0.2 and TCP = 0.8. Under our assumptions, optimized regimes, with the same overall time and dose, produce an NTCP of ∼ 0.11 and TCP of ∼ 0.83, a significant therapeutic gain over CLDR . Conclusion: Difference in repair rates between early- and late-responding tissues can be exploited to produce clinically practical protocols that are significantly superior to current regimens. Such optimized protocols produce slightly better tumor control than CLDR with the same overall dose and time, significantly less late damage, and similar early normal-tissue sequellae. Temporal optimization, thus, promises to be a powerful tool in designing better treatment protocols.

General equations for fractionated protracted irradiation have been applied to the analysis of mouse lung data derived from isoeffect protocols. The data were accrued from a spectrum of different protocols including different radiation qualities, interfraction times and dose-rates. This analysis, based upon two component repair rate processes, suggests that there are possibly two repair-rate processes involved in the repair of sublethal damage in the lung. The two repair half-lives were 0.32 and 1.92 h with a low dose-rate partitioning of 1:0.38 between the amount of lethal damage resulting from rapid and slow sublethal damage repair processes at low dose-rates. The analysis also indicates that there may be a dose-rate amplification of the amount of resultant lethal damage, deriving from sublethal damage, associated with the longer repair process. It is also shown that the alpha/beta ratio is probably independent of the radiation quality and that the ratios of multiple to single event damage for 240kVp X-rays and 60Co are almost identical. However, the absolute values of alpha and beta for 240 kVp X-rays may be greater than for 60Co.

Cells that have been pre-exposed to thermal stress can acquire a transient resistance against the killing effect of a subsequent thermal stress. The cause for this phenomenon, called thermotolerance, seems to be an enhanced resistance of proteins against thermal denaturation and aggregation. This resistance can be expressed as an attenuation of damage formation (less initial damage) or as a better repair of the protein damage (facilitated recovery). Heat Shock (or better, Stress) Proteins (HSPs) may play a role in and even be required for thermal resistance. However, rather than stress-induced enhanced synthesis and elevated total levels of HSPs per se, the concentration of, both constitutive and inducible, HSPs at and/or (re)distributed to specific subcellular sites may be the most important factor for the acquisition of thermotolerance. Specific HSPs may be involved either in damage protection or in damage repair.

Squamous cell carcinoma (SCC) cell lines recently established from head and neck tumors were studied for their capability of repairing sublethal radiation induced damage (SLDR). Total doses of 1.25, 2.50, 5.00, and 7.50 Gy were used either as a single dose or split in two equal fractions with a 24 h interval. Cell survival was determined using a 96-well plate clonogenic assay based on limiting dilution. Survival data was fitted by linear quadratic model, and the area under the survival curve (AUC) was obtained with numerical integration. The amount of SLDR was expressed as AUC-ratio comparing survivals from split dose vs single dose experiments. SLDR capacity was observed to vary markedly between individual cell lines (AUC-ratios 1.0-1.5). The relatively radiation-sensitive cell lines had a tendency toward higher SLDR proficiency (correlation coefficient 0.85). The differences in repair capacity could not be explained by the differences in doubling times of the cell lines. The inverse relationship between SLDR capacity and inherent radiosensitivity could explain the poor radiocurability of the sensitive donor tumors. Two of the most resistant cell lines were found SLDR deficient. This is a novel finding, since SLDR has been previously reported in all studied cells.

An evaluation of nine rapid runway repair (RRR) techniques was performed using the systems analysis approach. This analysis was based on a logical step-by-step procedure of examining the smallest details of each RRR system. The primary objective was to evaluate the RRR systems against criteria (evaluation factors) that were identified to be important in RRR. These criteria included repair time, cost, complexity, etc. The final results showed that the best RRR systems are asphalt blocks, fiberglass-reinforced plastic (FRP) mats, and FRP foldable mats. These repair techniques possess the desirable advantages in a RRR system. They are fast, simple, and cost effective, and extensive training is not required. This study was conducted methodically and each phase was carefully thought out. It reflects the opinions of the author and leading RRR experts. This analysis is not intended to make the decision of which RRR system to implement; it is merely a tool to clearly state the procedures, factors, and rationale that are used to make a decision. Keywords: Airfield Damage Repair (ADR), FRP, Infrared heater, Base survivability.

Purpose/Objective: The cytotoxic RNase, Onconase (ONC), may show promising therapeutic implication as an alternative for cisplatin and carboplatin. ONC showed inhibition of sublethal damage and potentially lethal damage repair in addition to protein synthesis by t-RNA cleavage. This led us to consider the therapeutic effectiveness of ONC cisplatin (or carboplatin) on A549 human lung tumors, including tumors previously untreatable by either cisplatin or carboplatin.

Purpose: To investigate the effects of radiation damage, tumor repopulation and cellular sublethal damage repair. Method and Materials: An expression of the Zaider‐Minerbo model obtained by Stavreva et al. is used to fit published dose‐response in vitro data from two cellular megacolony cultures. Results: The data analysis shows the importance of the linear‐quadratic mechanism of cell damage for the description of in vitrocell dynamics. In a previous work, where in vivo data were analyzed, the employment of the single hit model and cell repopulation produced the best fit, while ignoring the quadratic term in the current analysis leads to poor fits. Also, the best‐fit value of the probability of sublethal damage repair, τ, for both cell cultures tends to infinity, indicating that full recovery of the cells occurs between any two consecutive fractions. Conclusion: We conclude that the Zaider‐Minerbo model assuming full recovery of the cells between fractions accompanied by cell repopulation best fits the data from both cellular cultures investigated in the current work. However, a model assuming no repopulation returned a fit statistically indistinguishable from the fit produced by the Zaider‐Minerbo model, though at the expense of unusual best fit values of the cell radiosensitivity characteristics and a large value of τ. Therefore, we recommend the design of experiments using different fractionation regimes producing diverse data to help better analyze the TCP models and rank the models in accordance with statistical criteria.