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Aggregates are an important non-renewable resource and the primary raw material for land transport and building infrastructure. New Zealand as a country has an abundant endowment of rock minerals suitable for aggregate for the construction, maintenance, and recycling of public and private infrastructure. However, due to a deficit in infrastructure planning and development for a number of decades, strong population growth in many areas and much of New Zealand’s public infrastructure is coming to the end of its useful and/or economic life — there is an increasing demand for aggregates in many regions of New Zealand. Some regions of New Zealand have difficulties sourcing appropriate materials locally for infrastructure purposes, and there are increasing sensitivities to the extraction of aggregates from communities and iwi/hapu (tribes) who have experienced and seen the effects of poor industry extraction and environmental practices and the lack of monitoring and regulation of consent conditions. Little appropriate data is currently available either nationally or within regions to sustainably plan, manage, use and reuse/recycle aggregates for various public or private infrastructure and therefore to enable the forecasting of future aggregate demand. This paper develops a better understanding of the supply and demand issues both nationally and within regions with the aim of informing a future aggregate strategy to better manage aggregate resources. The paper reviews New Zealand and international literature, reviews aggregate and land use consent data, and evaluates novel methods of EROAD truck transponder data to evaluate aggregate haul distances. Finally, we provide recommendations on how to better manage aggregate supply and demand in New Zealand.

Hi, everyone. I am Monica Hakimi from the University of Michigan Law School, and I would like to welcome you to our panel on cyber power and its limits. The topic almost does not need an introduction. We all know just from reading the news that our collective dependence on cyberspace is also a huge vulnerability, and state and non-state actors exploit this vulnerability to do one another harm. They use cyber technologies not just to spy on one another, but also, for example, to interfere in national elections, to steal trade secrets or other valuable information, to disrupt the activities of political, military, or economic institutions, and at times to cause physical destruction or death.

The $R$-matrix analysis of $A=5$ nuclear systems has been partially validated by applying the technique to the $^{5}\mathrm{Li}$ system and comparing the predicted $\ensuremath{\gamma}$-ray spectrum with historical data. $R$-matrix analysis of the similar $^{5}\mathrm{He}$ system was then used to predict the $\ensuremath{\gamma}$-ray spectral shape for the deuterium-tritium (DT) reaction. The resulting spectra have been used in the analysis of DT implosions on the Omega laser where the $\ensuremath{\gamma}$-ray interaction rate was measured by a gas Cherenkov detector. Comparison of predictions to experiment confirmed the presence of both 16.75 and $\ensuremath{\approx}13$ MeV $\ensuremath{\gamma}$-ray contributions; analysis, using $R$-matrix spectra, yielded a ratio of $\ensuremath{\gamma}$-ray emission from a transition to the intermediate excited state to that from a transition to the ground state of $(2.1\ifmmode\pm\else\textpm\fi{}0.4):1$, substantiating the first spectral measurement of the DT fusion $\ensuremath{\gamma}$ ray in an inertial fusion environment.

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Prostaglandin E2 (PGE2), an arachidonic acid pathway metabolite produced by cyclooxygenase (COX)-1/2, has been shown to impair anti-tumor immunity through engagement with one or more E-type prostanoid receptors (EP1-4). Specific targeting of EP receptors, as opposed to COX-1/2 inhibition, has been proposed to achieve preferential antagonism of PGE2–mediated immune suppression. Here we describe the anti-tumor activity of MF-766, a potent and highly selective small-molecule inhibitor of the EP4 receptor. EP4 inhibition by MF-766 synergistically improved the efficacy of anti-programmed cell death protein 1 (PD-1) therapy in CT26 and EMT6 syngeneic tumor mouse models. Multiparameter flow cytometry analysis revealed that treatment with MF-766 promoted the infiltration of CD8+ T cells, natural killer (NK) cells and conventional dendritic cells (cDCs), induced M1-like macrophage reprogramming, and reduced granulocytic myeloid-derived suppressor cells (MDSC) in the tumor microenvironment (TME). In vitro experiments demonstrated that MF-766 restored PGE2-mediated inhibition of lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α production in THP-1 cells and human blood, and PGE2-mediated inhibition of interleukin (IL)-2-induced interferon (IFN)-γ production in human NK cells. MF-766 reversed the inhibition of IFN-γ in CD8+ T-cells by PGE2 and impaired suppression of CD8+ T-cells induced by myeloid-derived suppressor cells (MDSC)/PGE2. In translational studies using primary human tumors, MF-766 enhanced anti-CD3-stimulated IFN-γ, IL-2, and TNF-α production in primary histoculture and synergized with pembrolizumab in a PGE2 high TME. Our studies demonstrate that the combination of EP4 blockade with anti-PD-1 therapy enhances antitumor activity by differentially modulating myeloid cell, NK cell, cDC and T-cell infiltration profiles.

Widowed parents play a critical role in promoting family adaptation and facilitating their children's adjustment to the loss of a parent; yet the psychological wellbeing of these parents has received scant attention. In this study we examined depressive symptoms and grief intensity in 252 spousally bereaved men with dependent-age children. Participants learned of the study and completed initial surveys at variable time points during their first 2 years of bereavement. Depressive and grief symptoms remained persistently high, with 45% of the sample exceeding screening thresholds for clinically significant depressive symptoms two years after the death of their spouses. In linear regression models, higher intensity or frequency of depression and grief symptoms were associated with poorer psychological adaptation, lower parenting self-efficacy, and lower parenting satisfaction scores. Relationships between fathers' distress and potentially modifiable end-of-life variables regarding their spouses were examined. Notably, those who reported that their wives were at peace with dying had lower depressive and grief scores at various intervals. Overall, the magnitude and duration of the depressive and grief symptoms suggests that widowed fathers' psychological distress does not quickly abate over the first 2 years of bereavement, which may be attributable to the unique set of bereavement challenges facing widowed parents such as facilitating their children's grief, assuming sole parenting responsibilities, and managing a household on their own. The findings underscore the need to further examine emotional distress in widowed parents and how their wellbeing impacts family functioning. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Prostaglandin E2 (PGE2), an arachidonic acid pathway metabolite produced by cyclooxygenase (COX)-1/2, has been shown to impair anti-tumor immunity through engagement with one or more E-type prostanoid receptors (EP1-4). Specific targeting of EP receptors, as opposed to COX-1/2 inhibition, has been proposed to achieve preferential antagonism of PGE2–mediated immune suppression. Here we describe the anti-tumor activity of MF-766, a potent and highly selective small-molecule inhibitor of the EP4 receptor. EP4 inhibition by MF-766 synergistically improved the efficacy of anti-programmed cell death protein 1 (PD-1) therapy in CT26 and EMT6 syngeneic tumor mouse models. Multiparameter flow cytometry analysis revealed that treatment with MF-766 promoted the infiltration of CD8+ T cells, natural killer (NK) cells and conventional dendritic cells (cDCs), induced M1-like macrophage reprogramming, and reduced granulocytic myeloid-derived suppressor cells (MDSC) in the tumor microenvironment (TME). In vitro experiments demonstrated that MF-766 restored PGE2-mediated inhibition of lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α production in THP-1 cells and human blood, and PGE2-mediated inhibition of interleukin (IL)-2-induced interferon (IFN)-γ production in human NK cells. MF-766 reversed the inhibition of IFN-γ in CD8+ T-cells by PGE2 and impaired suppression of CD8+ T-cells induced by myeloid-derived suppressor cells (MDSC)/PGE2. In translational studies using primary human tumors, MF-766 enhanced anti-CD3-stimulated IFN-γ, IL-2, and TNF-α production in primary histoculture and synergized with pembrolizumab in a PGE2 high TME. Our studies demonstrate that the combination of EP4 blockade with anti-PD-1 therapy enhances antitumor activity by differentially modulating myeloid cell, NK cell, cDC and T-cell infiltration profiles.

To develop and validate an itemized costing algorithm for in-patient neonatal intensive care unit (NICU) costs for infants born prematurely that can be used for quality improvement and health economic analyses.We sourced patient resource use data from the Canadian Neonatal Network database, with records from infants admitted to 30 tertiary NICUs in Canada. We sourced unit cost inputs from Ontario hospitals, schedules of benefits, and administrative sources. Costing estimates were generated by matching patient resource use data to the appropriate unit costs. All cost estimates were in 2017 Canadian dollars and assigned from the perspective of a provincial public payer. Results were validated using previous estimates of inpatient NICU costs and hospital case-cost estimates.We assigned costs to 27 742 infants born prematurely admitted from 2015 to 2017. Mean (SD) gestational age and birth weight of the cohort were 31.8 (3.5) weeks and 1843 (739) g, respectively. The median (IQR) cost of hospitalization before NICU discharge was estimated as $20 184 ($9739-51 314) for all infants; $11 810 ($6410-19 800) for infants born at gestational age of 33-36 weeks; $30 572 ($16 597-$51 857) at gestational age of 29-32 weeks; and $100 440 ($56 858-$159 3867) at gestational age of29 weeks. Cost estimates correlated with length of stay (r = 0.97) and gestational age (r = -0.65). The estimates were consistent with provincial resource estimates and previous estimates from Canada.NICU costs for infants with preterm birth increase as gestation decreases and length of stay increases. Our cost estimates are easily accessible, transparent, and congruent with previous cost estimates.

Understanding of the thermonuclear burn in an inertial confinement fusion implosion requires knowledge of the local deuterium–tritium (DT) fuel density. Neutron imaging of the core now provides this previously unavailable information. Two types of neutron images are required. The first is an image of the primary 14-MeV neutrons produced by the D + T fusion reaction. The second is an image of the 14-MeV neutrons that leave the implosion hot spot and are downscattered to lower energy by elastic and inelastic collisions in the fuel. These neutrons are measured by gating the detector to record the 6–12 MeV neutrons. Using the reconstructed primary image as a nonuniform source, a set of linear equations is derived that describes the contribution of each voxel of the DT fuel region to a pixel in the downscattered image. Using the measured intensity of the 14-MeV neutrons and downscattered images, the set of equations is solved for the density distribution in the fuel region. The method is validated against test problems and simulations of high-yield implosions. The calculated DT density distribution from one experiment is presented.Understanding of the thermonuclear burn in an inertial confinement fusion implosion requires knowledge of the local deuterium–tritium (DT) fuel density. Neutron imaging of the core now provides this previously unavailable information. Two types of neutron images are required. The first is an image of the primary 14-MeV neutrons produced by the D + T fusion reaction. The second is an image of the 14-MeV neutrons that leave the implosion hot spot and are downscattered to lower energy by elastic and inelastic collisions in the fuel. These neutrons are measured by gating the detector to record the 6–12 MeV neutrons. Using the reconstructed primary image as a nonuniform source, a set of linear equations is derived that describes the contribution of each voxel of the DT fuel region to a pixel in the downscattered image. Using the measured intensity of the 14-MeV neutrons and downscattered images, the set of equat...

The double-shell platform fielded at the National Ignition Facility requires developments in new machining techniques and robotic assembly stations to meet the experimental specifications. Current double-shell target designs use a dense high-Z inner shell, a foam cushion, and a low-Z outer shell. The design requires that the inner shell be gas filled using a fill tube. This tube impacts the entire machining and assembly design. Other intermediate physics designs have to be fielded to answer physics questions and advance the technology to be able to fabricate the full point design in the near future. One of these intermediate designs is a mid-Z imaging design. The methods of designing, fabricating, and characterizing each of the major components of an imaging double shell are discussed with an emphasis on the fabrication of the machined outer metal shell.

Experiments and analysis in the 2 years since the 2015 Target Fabrication Meeting have resulted in further evolution of the requirements for high-performance layered implosions. This paper is a status update on the experimental program and supporting modeling, with emphasis on the implications for fabrication requirements. Previous work on the capsule support has continued, with various other support options being explored in experiments and modeling. Work also continues on ablator composition nonuniformities, with important new results from CH experiments on Omega, and the first three-dimensional X-ray transmission measurements of Be capsules on the National Ignition Facility. Work on hohlraums continues to include near-vacuum hohlraums and U hohlraums without a gold lining. Overall, the understanding that has been achieved, along with the progress in fabrication technology, represents good continuing progress toward the goal of fusion in the laboratory.

To examine rates and determinants of mother's own milk (MOM) feeding at hospital discharge in a cohort of infants born very preterm within the Canadian Neonatal Network (CNN).This was a population-based cohort study of infants born at33 weeks of gestation and admitted to neonatal intensive care units (NICUs) participating in the CNN between January 1, 2015, and December 31, 2018. We examined the rates and determinants of MOM use at discharge home among the participating NICUs. We used multivariable logistic regression analysis to identify independent determinants of MOM feeding.Among the 6404 infants born very preterm and discharged home during the study period, 4457 (70%) received MOM or MOM supplemented with formula. Rates of MOM feeding at discharge varied from 49% to 87% across NICUs. Determinants associated with MOM feeding at discharge were gestational age 29-32 weeks compared with26 weeks (aOR 1.56, 95% CI 1.25-1.93), primipara mothers (aOR 2.12, 95% CI 1.86-2.42), maternal diabetes (aOR 0.79, 95% CI 0.66-0.93), and maternal smoking (aOR 0.27, 95% CI 0.19-0.38). Receipt of MOM by day 3 of age was the major predictor of breast milk feeding at discharge (aOR 3.61, 95% CI 3.17-4.12).Approximately two-thirds of infants born very preterm received MOM at hospital discharge, and rates varied across NICUs. Supporting mothers to provide breast milk in the first 3 days after birth may be associated with improved MOM feeding rates at discharge.

Background: EGFR-activating mutations (L858R and ex19del) are major drivers (15-47%) of lung adenocarcinoma. EGFR TKI development has changed the treatment paradigm for EGFR-mutant (EGFR+) NSCLC. However, tumors often develop acquired resistance mutations to current TKIs leading to clinical progression. EGFR+/T790M is the most prevalent acquired resistance mutation after first- and second-generation TKI treatment. Osimertinib, a third-generation TKI which targets EGFR+/T790M, can overcome this resistance, but faces further resistance within 10-18 months. EGFR+/C797S is the most significant on-target resistance mechanism to osimertinib, leading to EGFR+/T790M/C797S double resistant mutants. There are currently no approved targeted therapies for patients with EGFR+/T790M/C797S NSCLC. BLU-945 is a potent and highly selective inhibitor of the EGFR+/T790M/C797S and EGFR+/T790M mutations, with in vivo activity in subcutaneous and intracranial EGFR-mutant tumor models. Method: In vivo antitumor activity of BLU-945 was evaluated in engineered triple mutant cell line-derived xenograft (CDX) models and osimertinib-resistant patient-derived xenograft (PDX) models of NSCLC. Plasma and tumor samples were collected for future pharmacokinetic and pharmacodynamic analyses. In vivo activity was also evaluated in an intracranial implantation model using luciferase-expressing YU-1097 patient-derived-cells harboring EGFRex19del/T790M/C797S resistance mutations, with the tumor burden of intracranial lesions measured by bioluminescence imaging. Results: Oral administration of BLU-945 to tumor-bearing mice showed potent EGFR pathway inhibition and significant single-agent antitumor activity at well-tolerated doses in the engineered osimertinib-resistant EGFRL858R/T790M/C797S CDX model, and an EGFRex19del/T790M/C797S PDX model. In addition, combination of BLU-945 with osimertinib showed enhanced antitumor activity compared with single-agent treatment in the EGFRex19del/T790M/C797S PDX model. Pharmacodynamic assays revealed treatment with BLU-945 resulted in marked inhibition of EGFR, AKT and ERK phosphorylation in the EGFRL858R/T790M/C797S CDX and EGFRex19del/T790M/C797S PDX models. BLU-945 also demonstrated potent activity in a patient-derived model of EGFRex19del/T790M/C797S implanted intracranially. Conclusion: BLU-945 is a potent, selective, and orally available fourth-generation EGFR inhibitor with robust antitumor activity in osimertinib-resistant NSCLC models grown subcutaneously and intracranially. BLU-945 shows activity as a single agent and in combination with other EGFR inhibitors. Clinical development of BLU-945 is expected in 2021. Citation Format: Sun Min Lim, Chae Won Park, Zhuo Zhang, Rich Woessner, Tom Dineen, Faith Stevison, John Hsieh, Meredith Eno, Doug Wilson, John Campbell, Caitlin Utt, Faris Albayya, Nicolas Lamontagne, Marion Dorsch, Klaus Hoeflich, Byoung Chul Cho, Stefanie Schalm. BLU-945, a fourth-generation, potent and highly selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) with intracranial activity, demonstrates robust in vivo antitumor activity in models of osimertinib-resistant non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1467.

Background: Cyclin dependent kinases (CDK) comprise a family of proteins which are activated upon cyclin binding to promote cell cycle progression. Historically, CDK family inhibitors have had limited utility in the clinic due to 1) toxicities associated with broad spectrum CDK inhibition; and 2) varied and unpredictable efficacy due to lack of a patient selection strategy. The recent approval of three selective CDK4/6 drugs (palbociclib, ribociclib and abemaciclib) has revived the pursuit of therapies against a related interphase kinase, CDK2. Cyclin E gene (CCNE) alterations are prevalent in cancers with high unmet medical need and are emerging as a potential mechanism of clinical resistance to targeted therapies (e.g. CDK4/6 therapies). Methods: Here we report preclinical validation leading to the development of a selective CDK2 inhibitor for the treatment of cancers harboring CCNE alterations. We highlight advanced, orally bioavailable compounds exhibiting single-digit low nanomolar biochemical and cellular potency (pRB), exquisite CDK family selectivity (CDK1, 4, 6, 7 and 9), and whole kinome selectivity. We have characterized the phenotypic and mechanistic consequences of targeting CDK2, employing both genetic and pharmacologic methods across cell lines and xenograft models (e.g. OVCAR-3, MKN-1, HCC1569). Results: In a panel of cell lines, CCNE1-amplified lines exhibited profound sensitivity to selective CDK2 inhibition by halting cells at the G1/S phase of the cell cycle. Upon further inspection, CDK2 inhibition induced multiple markers of senescence, e.g. SA-b-gal and IL-6, in CCNE1-amplified but not in CCNE non-amplified cell lines. Consistent with this, these compounds exhibit robust anti-tumor activity in multiple CCNE1-amplified xenograft models, which was sustained after removal of treatment with these compounds. Conclusions: These data provide a strong rationale for advancing this class of compounds toward clinical development in CCNE-altered cancers. Citation Format: Yoon J. Choi, Steve Wenglowsky, Victoria Brown, Neil Bifulco, Yeon S. Choi, Jian Guo, Megan Hatlen, Joseph Kim, Tim LaBranche, Riadh Lobbardi, Emanuele Perola, Emily Rozsahegyi, Michelle Maynard, Phil Ramsden, Grace Silva, Faith Stevison, Richard Vargas, Ruduan Wang, Doug Wilson, Rich Woessner, Dean Zhang, Rob Meissner, Klaus Hoeflich, Marion Dorsch. Development of a selective CDK2-E inhibitor in CCNE driven cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1279.

Background One of the controversies in the management of twin gestations relates to mode of delivery, especially when the second twin is in a nonvertex presentation (Vertex/nonVertex pairs) and birth is imminent at extremely low gestation. Objective We hypothesized that, for Vertex/nonVertex twins born before 28 weeks’ gestation, cesarean delivery would be associated with a lower risk of adverse neonatal outcomes than trial of vaginal delivery. Our aim was to test this hypothesis by comparing the neonatal outcomes of Vertex/nonVertex twins born before 28 weeks’ gestation by mode of delivery using a large national cohort. Study Design This work is a retrospective cohort study of all twin infants born at 240/7 to 276/7 weeks’ gestation and admitted to level III neonatal intensive care units participating in the Canadian Neonatal Network (2010–2017). Exposure is defined a trial of vaginal delivery for Vertex/nonVertex twins. Nonexposed (control) groups are defined as cases where both twins were delivered by cesarean delivery, either in vertex or nonvertex presentation (control group 1) or owing to the nonvertex presentation of the first twin (control group 2). Outcome measures are defined as a composite of neonatal death, severe neurologic injury, or birth trauma. Results A total of 1082 twin infants (541 twin pairs) met the inclusion criteria: 220 Vertex/nonVertex pairs, of which 112 had a trial of vaginal delivery (study group) and 108 had cesarean delivery for both twins (control group 1); 170 pairs with the first twin in nonvertex presentation, all of which were born by cesarean delivery (control group 2); and 151 pairs with both twins in vertex presentation (vertex or nonvertex). In the study group, the rate of urgent cesarean delivery for the second twin was 30%. The rate of the primary outcome in the study group was 42%, which was not significantly different compared with control group 1 (37%; adjusted relative risk, 0.93; 95% confidence interval, 0.71–1.22) or control group 2 (34%; adjusted relative risk, 1.20; 95% confidence interval, 0.92–1.58). The findings remained similar when outcomes were analyzed separately for the first and second twins. Conclusion For preterm Vertex/nonVertex twins born at

Converting and using the National Ignition Facility (NIF) to deliver 527 nm light instead of its current 351 nm would allow the laser to deliver more energy and power to ignition targets. We update previous 527 nm target design work to reflect more contemporary target designs using high-density carbon capsules and low density helium gas filled Hohlraums. We extend single shell capsule designs based on current experimental results to higher energy and power and also explore double shell capsules, both driven by green light. These studies were completed using detailed pulse shapes found for targets that converged with acceptable 2D implosion symmetries and then used the Lava Lamp II code to confirm their feasibility at NIF. A 1.2× dimensional scaleup of one tuned NIF target at the limit of its current 351 nm capabilities and shot 170827 uses 3.3 MJ, at the limit of the current NIF's 527 nm capability. With the less-structured pulse of a double shell target, 3.7 MJ could be delivered by the laser. Our LPI calculations do not preclude operation at 527 nm, particularly for low fill Hohlraums, and suggest that the stimulated Raman backscatter may be no worse than the small quantities seen in 170827; stimulated forward Raman scattering may be present. If Stimulated Brillouin Scattering is too great, the much greater laser bandwidth available at 527 nm could be used to decrease backscatter. These larger targets with higher energy and power may offer a better chance of achieving ignition with only modest changes to the NIF laser.

Double shell capsule implosions are an alternative approach to achieving alpha heating on the National Ignition Facility. Current machining techniques construct the outer shell as two hemispheres that are glued together, and the deuterium and tritium (DT) liquid inside the inner shell will be injected by a fill tube. These features introduce asymmetries and jetting that may disrupt the confinement of the DT fuel if not carefully controlled. Simulations indicate that in order to achieve high yields in the laboratory, these features as well as susceptibility to the Rayleigh–Taylor instability (RTI) must be mitigated. Due to uncertainties in computational models and the expense of using the best physics models at adequate resolution in three dimensions, our computational modeling must be constrained by experiments. We report on the results of recent hydrogrowth radiography and dual-axis keyhole experiments with double shell targets that have been used to evaluate our modeling of the outer shell joint as well as the impacts of high-energy x-ray preheat that strongly impacts RTI growth. Our simulations show good agreement with the experimental data and inform several important modeling choices.

Experiments and analysis in the 3 years since the 2012 Target Fabrication Meeting have resulted in significant improvement in understanding of the requirements for high-performance layered implosio...

Impaired cardiorespiratory fitness is associated with inferior survival in patients preparing to undergo hematopoietic cell transplantation (HCT). Exercise training based on short, higher-intensity intervals has the potential to efficiently improve cardiorespiratory fitness. We studied home-based interval exercise training (IET) in 40 patients prior to autologous (N=20) or allogeneic (N=20) HCT. Each session consisted of 5, three-minute intervals of walking, jogging, or cycling at 65-95% maximal heart rate (MHR) with 3 minutes of low intensity exercise (

IntroductionPreterm birth (birth

Double shell targets1 on the National Ignition Facility (NIF) provide for an alternative path to a high yield experiment compared to the single shells. The concept of the design is that through kinetic energy transfer between an outer ablator and inner pusher, conditions needed for robust burn can be achieved with a lower convergence ratio and internal temperature compared to a single shell. Due to the multilayer construction of the target, features that can perturb any of the multiple layers of the capsule and degrade target performance are a concern. Understanding the mechanics of these degradations and ways to prevent them is extremely important for a successful design.