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Polyethylene (PE) is the most widely produced synthetic polymer. By installing chemically cleavable bonds into the backbone of PE, it is possible to produce chemically deconstructable PE derivatives; to date, however, such designs have primarily relied on carbonyl‐ and olefin‐related functional groups. Bifunctional silyl ethers (BSEs; SiR2(OR′2)) could expand the functional scope of PE mimics as they possess strong Si−O bonds and facile chemical tunability. Here, we report BSE‐containing high‐density polyethylene (HDPE)‐like materials synthesized through a one‐pot catalytic ring‐opening metathesis polymerization (ROMP) and hydrogenation sequence. The crystallinity of these materials can be adjusted by varying the BSE concentration or the steric bulk of the Si‐substituents, providing handles to control thermomechanical properties. Two methods for chemical recycling of HDPE mimics are introduced, including a circular approach that leverages acid‐catalyzed Si−O bond exchange with 1‐propanol. Additionally, despite the fact that the starting HDPE mimics were synthesized by chain‐growth polymerization (ROMP), we show that it is possible to recover the molar mass and dispersity of recycled HDPE products using step‐growth Si−O bond formation or exchange, generating high molecular weight recycled HDPE products with mechanical properties similar to commercial HDPE. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) is the most widely produced synthetic polymer. By installing chemically cleavable bonds into the backbone of PE, it is possible to produce chemically deconstructable PE derivatives; to date, however, such designs have primarily relied on carbonyl‐ and olefin‐related functional groups. Bifunctional silyl ethers (BSEs; SiR2(OR′2)) could expand the functional scope of PE mimics as they possess strong Si−O bonds and facile chemical tunability. Here, we report BSE‐containing high‐density polyethylene (HDPE)‐like materials synthesized through a one‐pot catalytic ring‐opening metathesis polymerization (ROMP) and hydrogenation sequence. The crystallinity of these materials can be adjusted by varying the BSE concentration or the steric bulk of the Si‐substituents, providing handles to control thermomechanical properties. Two methods for chemical recycling of HDPE mimics are introduced, including a circular approach that leverages acid‐catalyzed Si−O bond exchange with 1‐propanol. Additionally, despite the fact that the starting HDPE mimics were synthesized by chain‐growth polymerization (ROMP), we show that it is possible to recover the molar mass and dispersity of recycled HDPE products using step‐growth Si−O bond formation or exchange, generating high molecular weight recycled HDPE products with mechanical properties similar to commercial HDPE. [ABSTRACT FROM AUTHOR]

Background: Atrophy of the rotator cuff is a negative prognostic indicator after rotator cuff repair. Although full-thickness rotator cuff tears accompanied by tendon retraction are commonly associated with decreased muscle cross-sectional area (CSA) on magnetic resonance imaging (MRI), it is unclear whether this is accompanied by histologic atrophy of rotator cuff myofibers. Purpose: To evaluate the effect of supraspinatus tendon retraction and myofiber size on supraspinatus atrophy on MRI. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Supraspinatus muscle biopsy specimens were obtained from consecutive patients undergoing arthroscopic shoulder surgery. Rotator cuff tears were classified according to size. Preoperative MRI was used to measure tendon retraction and CSA of the supraspinatus muscle in the Y-shaped view. The occupation ratio of the supraspinatus was calculated by dividing the supraspinatus CSA by the supraspinatus fossa CSA. Muscle biopsy specimens were examined using laminin to quantify myofiber CSA. The association between supraspinatus tear size and measures of histologic and MRI muscle atrophy were compared using standard statistical tests. Multivariable logistic regression analysis was used to identify independent predictors of muscle atrophy on MRI. Results: A total of 38 patients were included: 8 with no tear, 14 with a partial-thickness tear, and 16 with a full-thickness tear. Increasing tear size was associated with greater distance of tendon retraction (P <.001), smaller mean histologic myofiber size (P =.004), lower mean supraspinatus CSA on MRI (P <.001), and lower occupation ratio: 0.73 (control), 0.66 (partial tear), 0.53 (small to medium full-thickness tear), and 0.38 (large to massive full-thickness) (P <.001). On Pearson correlation analysis, tendon retraction demonstrated strong correlation with occupation ratio (–0.725; P <.001) and weak correlation with myofiber size (–0.437; P =.006), while occupation ratio showed moderate correlation with myofiber size (0.593; P <.001). Multivariable linear regression analysis demonstrated that increasing tendon retraction (P <.001), age (P =.034), and smaller histologic myofiber CSA (P =.047) were independently associated with greater supraspinatus atrophy on MRI. Conclusion: Supraspinatus muscle atrophy appreciated on MRI is independently associated with patient age, tendon retraction, and atrophy of the supraspinatus myofibers at the histologic level. [ABSTRACT FROM AUTHOR]

The article reports that United States president Joseph R. Biden administration has requested funding for the "PrEP for All to End the HIV Epidemic" program as part of the financial year 2023 budget, following years of unsuccessful efforts to reduce HIV infection rates and address racial disparities. It mentions that the program ensure fair pricing for PrEP medications and related laboratory tests for uninsured individuals, and invest in community education efforts.

The U.S. has the tools to end the HIV epidemic, but progress has stagnated. A major gap in U.S. efforts to address HIV is the under-utilization of medications that can virtually eliminate acquisition of the virus, known as pre-exposure prophylaxis (PrEP). This document proposes a financing and delivery system to unlock broad access to PrEP for those most vulnerable to HIV acquisition and bring an end to the HIV epidemic. [ABSTRACT FROM AUTHOR]

Transgender and gender diverse (TGD), Black, and Latinx communities have long borne a disproportionate share of the U.S. HIV epidemic, yet these same key demographics are continually underrepresented in national PrEP prescriptions. Black, Latinx, and TGD individuals are also more likely to be uninsured, meaning that a proposed federal program to cover PrEP for people without insurance could provide significant benefit to potential PrEP users from these populations. However, coverage of PrEP costs alone will not end disparities in uptake. This commentary provides additional context and recommendations to maximize effectiveness of a national PrEP program for TGD, Black, and Latinx populations in the US. [ABSTRACT FROM AUTHOR]

The current U.S. emission control requirements for on-road motor vehicles are driven by the ozone problem in the South Coast Air Basin (SoCAB) in southern California. Based on ozone modeling performed for Air Quality Management Plans (AQMPs), the SoCAB ozone attainment plan requires large (>80%) amounts of emission reductions in oxides of nitrogen (NOx) from current levels with more modest (~40%) controls on Volatile Organic Compounds (VOC). The shelter in place orders in response to the 2020 COVID-19 pandemic resulted in an immediate reduction in emissions, but instead of ozone being reduced, in 2020 the SoCAB saw some of the highest observed ozone levels in decades. We used the abrupt emissions reductions from 2019 to 2020 caused by COVID-19 to conduct a dynamic model evaluation of the Community Multiscale Air Quality (CMAQ) model to evaluate whether the models used to develop ozone control plans can correctly simulate the ozone response to the emissions reductions. Ozone modeling was conducted for three scenarios: 2019 Base, 2020 business-as-usual (i.e., without COVID reductions), and 2020 COVID. We found that modeled ozone changes between 2019 and 2020 were generally consistent with the observed ozone changes. We determined that meteorology played the major role in the increases in ozone between 2019 and 2020; however, the reduction in NOX emissions also caused ozone increases in Los Angeles County and into western San Bernardino County, with more widespread ozone decreases further to the east. [ABSTRACT FROM AUTHOR]

The article presents information related to the prehistoric Kiamichi blade discovered at Kiamichi River and Valley in Arkansas and Oklahoma in 2021 by archeologist Jeremiah R. H. Johnson. It describes the physical characteristics of the type 1 and type 2 variants of the blade with an elliptical cross section with signs of resharpening. It explains the similarities of these Kiamichi with the points of McKean Complex of the High Plains.

For Graph HT ht , there can be no more solutions. Suppose now that Graph HT ht , but Graph HT ht . Now suppose that Graph HT ht . [Extracted from the article]

The increasing role of schools in promoting financial literacy underscores the need to investigate the effectiveness of school-based financial education programs. This study examined FutureSmart—a free, co-curricular, online financial education course—using a quasi-experimental design with a diverse sample of middle school students nationwide. The study assessed the impact of the course on students' financial knowledge, attitudes, and behaviors, and explored the association of program implementation factors with changes in student outcomes. Financial knowledge gains were significant, substantial, and consistent across student subgroups and implementation factors for FutureSmart participants. Gains in financial attitudes and behaviors—specifically, financial confidence, engagement with parents about financial issues, current engagement with financial products, and intended future engagement with financial products—were not significant. The fundamental implication of this research is that FutureSmart effectively conveys financial knowledge to middle school students, contributing to a foundation for their future financial well-being. [ABSTRACT FROM AUTHOR]

Radiation management literature focused on optimizing care for patients with intellectual disability is sparse. We add our experience to the literature with the goal to improve care to this vulnerable patient population. To this end, we report three cases of prostate cancer in patients with limited cognition who were treated with low dose rate (LDR) prostate brachytherapy to highlight an effective strategy to deliver optimal care to this group of patients. This is a case series of three adult male patients with limited cognition each of whom developed prostate cancer which was managed primarily with LDR brachytherapy. Patient #1: A 53-year-old male with favorable intermediate-risk prostate cancer (PSA 8.8 ng/ml, Grade Group 2), Patient #2: a 68-year-old male with unfavorable intermediate risk prostate cancer (PSA 12.6 ng/ml, Grade Group 3), and Patient #3: a 52-year-old male with high-risk prostate cancer (PSA 24 ng/ml, Grade Group 1), all of whom had intellectual disability, were evaluated for radiation therapy. A thorough discussion occurred with each patient and their legal guardian about prostate cancer therapy options including surgery versus radiation treatment with or without androgen deprivation therapy. Radiation therapy treatment strategies presented included low dose rate brachytherapy versus external beam radiation treatment including SBRT to a total dose of 3625 cGy in 5 fractions every other day or a moderately hypofractionated regimen to a total dose of 7000 cGy in 28 daily fractions Monday to Friday. In each case, a shared decision was made for each patient to undergo interstitial prostate seed implant. Of note, two out of the three patients lived more than an hour away from the radiation treatment center and relied on family support for transportation needs. Each patient initially underwent a prostate volume study with a transrectal ultrasound to 1) determine the dimensions of the prostate and 2) develop a plan for radiation dose coverage of the prostate with interstitial Cs-131 brachytherapy seeds. Each patient then underwent seed implantation under anesthesia followed by fluoroscopy and post-implant CT, to assess for appropriate seed placement as well as the post-implant dosimetry. Patient #1 received a total prescription dose of 110 Gy to the prostate D90 using 61 sources each with a strength of 1.6 U per seed for a total strength of 97.6 U and at 14 months follow up, his PSA had decreased to 1.7 ng/ml from 8.8 ng/ml. Patient #2 received a total prescription dose of 100 Gy to the prostate D90 using 59 sources each with a strength of 1.43 U per seed for a total strength of 84.37 U, and at 38 months follow up, his PSA had decreased to 0.018 ng/ml from 12.6 ng/ml. Patient #3 received 115 Gy to the prostate D90 using 90 sources each with a strength of 1.8 U per seed for a total of 162 U, and at 34 months follow up, his PSA had decreased to 0.8 ng/mL from 24 ng/ml. In all three cases, treatment was completed without complications and there was no CTCAE grade 3 or higher toxicity noted. In patients with limited cognition with select non-metastatic prostate cancer, low dose rate brachytherapy is an excellent treatment modality. It provides adequate tumor control with acceptable radiation induced toxicities. It reduces the transportation burden associated with multiple treatment sessions by requiring only two visits to a radiation treatment center. The use of sedation reduces the challenge associated with patient immobilization encountered with external beam radiation treatments. And, it is less invasive than surgery. These advantages for LDR brachytherapy are extremely useful for patients with limited cognition. Thus, LDR brachytherapy should be strongly considered for this patient population when applicable. [ABSTRACT FROM AUTHOR]

Effective treatment for locally-advanced vulvar cancer remains a challenge and often requires multi-modality care. Unresectable disease may be managed with a combination of chemotherapy, external beam radiation (EBRT), and brachytherapy. Cesium-131 Low Dose Rate (LDR) interstitial brachytherapy is an effective modality to deliver high-quality localized radiation. This case report highlights the technique and efficacy of Cesium-131 LDR interstitial brachytherapy as a part of multimodal therapy in treating a medically inoperable patient with advanced age and multiple medical comorbidities. Patient is a 79-year-old female who presented with medically inoperable FIGO Stage IVA squamous cell carcinoma of the vulva with extensive left labial disease and circumferential extension into the upper vagina. In addition, patient had hypermetabolic left inguinal lymph node metastasis on PET/CT imaging. Patient was subsequently treated with EBRT (4930 cGy over 29 fractions was delivered to the vulva, vagina, and regional lymphatics, followed by a sequential boost of 1620 cGy over 9 fractions to the involved left inguinal lymph node) with concurrent weekly cisplatin. Following EBRT, the patient had residual disease burden. She was noted to have cobblestoning of the anterior vaginal wall extending laterally on both sides, with palpably bulky disease in roughly the 10 o'clock position along her right lateral vaginal wall. She was offered High Dose Rate (HDR) interstitial brachytherapy boost, but declined this treatment due to her age and multiple medical comorbidities. She was subsequently treated with Cesium-131 LDR interstitial brachytherapy. Cesium-131 interstitial free seeds were placed with the seed inserters starting proximally and extending distally along the anterior vaginal wall in a planer fashion. 3000 cGy was prescribed to the tumor using 28 sources, each with a strength 0.72 U per seed. Dose distribution is represented in Figure 1 (Coronal CT scan demonstrating the radiation dose distribution of Cesium-131 permanent LDR implant to gross residual vaginal disease following EBRT). This was followed by vaginal cylinder HDR intracavitary brachytherapy utilizing Iridium-192 (800 cGy was prescribed at 5 mm depth from the vaginal cylinder surface delivered over 2 fractions). PET/CT done at 3 months showed complete metabolic resolution of all disease without evidence of recurrent or metastatic disease. At the patient's 21-month follow up, she had no evidence of disease on clinical exam or PET/CT imaging at that time. Acute toxicities included CTCAE grade 2-3 vulvar and inguinal skin erythema and mild diarrhea. Late toxicities include vaginal wall fibrosis at the site of Cesium-131 implant. Cesium-131 LDR interstitial brachytherapy implementation in a multimodal therapy setting is proved to be a feasible and promising treatment option to achieve long-term local control in a medically inoperable patient with an extensive vulvovaginal neoplasm. This study demonstrates a proof of concept of the safety and viability of Cesium-131 LDR interstitial brachytherapy for definitive management in selective patient populations. Future research is warranted. [ABSTRACT FROM AUTHOR]

This special edition of JLME centers on a novel proposal for a national PrEP access program with the potential to break through a failed status quo. [ABSTRACT FROM AUTHOR]

Engaging undergraduate students in large classes is a constant challenge for many lecturers, as student participation and engagement can be limited. This is a concern since there is a positive correlation between increased engagement and student success. The lack of student feedback on content delivery prevents lecturers from identifying topics that would benefit students if reviewed. Implementing novel methods to engage the students in course content and create ways by which they can inform the lecturer of the difficult concepts is needed to increase student success. In the present study, we investigated the use of Twitter as a scalable approach to enhance engagement with course content and peer-to-peer interaction in a large course. In this pilot study, students were instructed to tweet the difficult concepts identified from content delivered by videos. A software program automatically collected and parsed the tweets to extract summary statistics on the most common difficult concepts, and the lecturer used the information to prepare face-to-face (F2F) lectorial sessions. The key findings of the study were 1) the uptake of Twitter (i.e., registration on the platform) was similar to the proportion of students who participated in F2F lectorials, 2) students reviewed content soon after delivery to tweet difficult concepts to lecturer, 3) Twitter increased engagement with lecturers, 4) the difficult concepts were similar to previous years, yet the automated gathering of Twitter data was more efficient and time saving for the lecturer, and 5) students found the lectorial review sessions very valuable. [ABSTRACT FROM AUTHOR]

Background: Non-insertional Achilles tendinopathy is a common disorder that may be treated with surgical debridement. A flexor hallucis longus (FHL) transfer is recommended if debridement of ≥50% is performed; however, there are no biomechanical data to support this. The purpose of this study was to assess the added biomechanical strength provided by an FHL transfer with incrementally sized non-insertional Achilles tendon defects.Methods: Thirty matched-pair below-the-knee cadaveric specimens (n = 60) (mean age at the time of donor death, 67 years; range, 36 to 74 years) were obtained and randomly divided into 3 groups according to whether the defect was 25%, 50%, or 75% of the tendon width. One specimen of each pair was then randomly selected to undergo FHL transfer using interference screw fixation. All specimens then underwent cyclic loading of 100 N, and elongation of the medial and lateral limbs of the tendon defect was recorded. The constructs were then loaded to failure to measure stiffness, ultimate strength, and peak elongation before failure.Results: The specimens with a 75% defect had significantly less elongation of the medial and lateral tendon-defect limbs when an FHL transfer had been done (p < 0.05). Ultimate load to failure was significantly increased in all groups (by 242 to 270 N depending on the defect size) following FHL transfer. Failures usually occurred through the tendon defect in the 75% and 50% defect groups, whereas all failures occurred at the Achilles tendon insertion when a 25% defect had been created. No significant differences were found in peak elongation with the addition of an FHL transfer. FHL augmentation resulted in significantly greater stiffness in the 25% and 75% defect groups (p < 0.05).Conclusions: This study showed that an FHL transfer significantly increased load to failure of Achilles tendons with a non-insertional defect involving 25%, 50%, and 75% of the tendon width. The mechanism of failure was usually through the defect in the specimens with a 50% or 75% defect, supporting the use of FHL augmentation with debridement of ≥50%.Clinical Relevance: The present study supports the mechanical concept that FHL transfer is indicated when debridement of the Achilles tendon is ≥50%. [ABSTRACT FROM AUTHOR]

A review is offered for the Central Plains Stone Age Fair, an artifact exhibition, held in Fairview, Oklahoma on October 1, 2022.

Summary: This article presents an algorithm to aid practitioners in determining the most appropriate method to estimate carbon dioxide emissions from an electricity load. Applications include sustainability assessments of products, processes, energy efficiency improvements, changes in generation infrastructure, and changes in electricity demand. Currently, there is no consensus on appropriate methods for calculating greenhouse gas emissions resulting from specific electricity loads. Previous research revealed significant differences in emissions when different methods were used, a situation that could result in divergent sustainability or policy recommendations. In this article, we illustrate the distribution of emissions estimates based on method characteristics such as region size, temporal resolution, average or marginal approaches, and time scales. Informed by these findings, a decision support algorithm is presented that uses a load's key features and an analyst's research question to provide recommendations on appropriate method types. We defined four different cases to demonstrate the utility of the algorithm and to illustrate the variability of methods used in previous studies. Prior research often employed simplifying assumptions, which, in some cases, can result in electricity being allocated to the incorrect generating resources and improper calculation of emissions. This algorithm could reduce inappropriate allocation, variability in assumptions, and increase appropriateness of electricity emissions estimates. [ABSTRACT FROM AUTHOR]

Protected areas not allowing extractive activities (here called fully protected area) are a spatially explicit conservation management tool commonly used to ensure populations persistence. This is achieved when an adequate fraction of a species' population spends most of its time within the boundaries of the protected area. Within a marine context, home ranges represent a tractable metric to provide guidance and evaluation of fully protected areas. We compiled peer-reviewed literature specific to the home ranges of finfishes and invertebrates of ecological and/or commercial importance in the Mediterranean Sea, and related this to the size of 184 Mediterranean fully protected areas. We also investigated the influence of fully protected areas size on fish density in contrast to fished areas with respect to home ranges. Home range estimations were available for 11 species (10 fishes and 1 lobster). The European spiny lobster Palinurus elephas had the smallest home range (0.0039 ± 0.0014 km 2 ; mean ± 1 SE), while the painted comber Serranus scriba (1.1075 ± 0.2040 km 2 ) had the largest. Approximately 25% of Mediterranean fully protected areas are larger than 2 times the size of the largest home range recorded. Fish densities were significantly higher when fully protected areas were larger than the home range, while no change in density occurred when home ranges were larger than fully protected areas. These results display a direct link between the effectiveness of fully protected areas and species' home range, suggesting that fully protected areas of at least 3.6 km 2 may increase the density of local populations of these coastal marine species. [ABSTRACT FROM AUTHOR]

To assess the accuracy and physiological relevance of circulating microRNA (miRNA) as a biomarker of pediatric concussion, we compared changes in salivary miRNA and cerebrospinal fluid (CSF) miRNA concentrations after childhood traumatic brain injury (TBI). A case-cohort design was used to compare longitudinal miRNA concentrations in CSF of seven children with severe TBI against three controls without TBI. The miRNAs 'altered' in CSF were interrogated in saliva of 60 children with mild TBI and compared with 18 age- and sex-matched controls. The miRNAs with parallel changes (Wilcoxon rank sum test) in CSF and saliva were interrogated for predictive accuracy of TBI status using a multivariate regression technique. Spearman rank correlation identified relationships between miRNAs of interest and clinical features. Functional analysis with DIANA mirPath identified related mRNA pathways. There were 214 miRNAs detected in CSF, and 135 (63%) were also present in saliva. Six miRNAs had parallel changes in both CSF and saliva (miR-182-5p, miR-221-3p, mir-26b-5p, miR-320c, miR-29c-3p, miR-30e-5p). These miRNAs demonstrated an area under the curve of 0.852 for identifying mild TBI status. Three of the miRNAs exhibited longitudinal trends in CSF and/or saliva after TBI, and all three targeted mRNAs related to neuronal development. Concentrations of miR-320c were directly correlated with child and parent reports of attention difficulty. Salivary miRNA represents an easily measured, physiologically relevant, and accurate potential biomarker for TBI. Further studies assessing the influence of orthopedic injury and exercise on peripheral miRNA patterns are needed. [ABSTRACT FROM AUTHOR]

One method to reduce wind variability is to diversify the wind power resource by interconnecting wind resources across a larger geography. This study uses a modified version of mean-variance portfolio optimization (MVP) to assess the potential for diverse wind to reduce the variability of wind. A one year unit commitment and economic dispatch model of the U.S. Midwest is used to understand the value of the reduced variability. The model assesses four different wind portfolios, ranging in diversity, of two wind power penetrations (10% of total system load and 20%). Employing MVP, the variance in the ramp rates decrease by 50% with a 4% increase in capacity in the 20% wind penetration and a 2% increase in the 10% penetration. With a 20% wind penetration, decreasing the ramp rate variance can reduce curtailment from 5% to 0.1%. In the absence of significant curtailment, decreasing the ramp rate variance reduces the proportion of conventional generation required for ramping. However, the impact on total production cost and emissions from conventional generation is complicated by complexities of the power system, including transmission constraints and the time of day of ramping. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of subfreezing temperatures on the behavior and ultimate capacity of GFRP-reinforced concrete beams. Duplicate beam specimens at four temperatures (20 °C, 0 °C, − 20°C, and − 40 °C) were tested in four-point bending until failure, while monitoring applied load and resulting deflection. The ultimate capacity of the beams was observed to increase with decreasing temperature, a result attributed to the effects of temperature on the compressive and tensile capacities of the concrete. Further, the increased tensile capacity of the concrete with decreasing temperature caused a noted difference in the post-cracking response of the beams: an increase in magnitude of drops in the force-deflection response associated with cracking. The method proposed by ACI 440 (2006) for calculating the ultimate capacity of GFRP reinforced beams accurately predicted the capacity of the beams in this investigation, with an average measured to predicted ratio 1.00 using the measured concrete properties and 1.03 using the design concrete properties. [ABSTRACT FROM AUTHOR]

The junction functionality of polymer networks is a key design variable to tune the material properties through changing the network connectivity. Here, we perform a Monte Carlo simulation to study the topology and elasticity of end-linked polymer networks constructed by junctions with different functionalities. The effect of junction functionality on the topological structure of the network displays both universal features and odd-even effects. For all junction functionalities, the primary loop fraction shows a linear dependence on the dimensionless product of concentration with single chain pervaded volume. The slopes of the lines exhibit strong odd-even alternation: primary loops are formed more frequently for junctions with an odd number of functional groups. The secondary loop fraction has a maximum when plotted against the normalized primary loop fraction, where the value of the maximum also shows odd-even alternation. The topological information obtained through Monte Carlo simulation is then incorporated into the modified affine network theory and modified phantom network theory (real elastic network theory). For affine networks, the odd-even alternation in the cyclic topology leads to nonmonotonic dependence of elastic modulus on the junction functionality. For phantom networks, the effect of decreasing junction fluctuations due to a larger number of interjunction connections dominates over the changes in loop concentration as junction functionality increases, leading to monotonically increasing elastic modulus with junction functionality. [ABSTRACT FROM AUTHOR]

The use of light to mediate controlled radical polymerization has emerged as a powerful strategy for rational polymer synthesis and advanced materials fabrication. This review provides a comprehensive survey of photocontrolled, living radical polymerizations (photo-CRPs). From the perspective of mechanism, all known photo-CRPs are divided into either ( l) intramolecular photochemical processes or (2) photoredox processes. Within these mechanistic regimes, a large number of methods are summarized and further classified into subcategories based on the specific reagents, catalysts, etc., involved. To provide a clear understanding of each subcategory, reaction mechanisms are discussed. In addition, applications of photo-CRP reported so far, which include surface fabrication, particle preparation, photoresponsive gel design, and continuous flow technology, are summarized. We hope this review will not only provide informative knowledge to researchers in this field but also stimulate new ideas and applications to further advance photocontrolled reactions. [ABSTRACT FROM AUTHOR]

Due to the complexity of power systems, tracking emissions attributable to a specific electrical load is a daunting challenge but essential for many environmental impact studies. Currently, no consensus exists on appropriate methods for quantifying emissions from particular electricity loads. This paper reviews a wide range of the existing methods, detailing their functionality, tractability, and appropriate use. We identified and reviewed 32 methods and models and classified them into two distinct categories: empirical data and relationship models and power system optimization models. To illustrate the impact of method selection, we calculate the CO2 combustion emissions factors associated with electric-vehicle charging using 10 methods at nine charging station locations around the United States. Across the methods, we found an up to 68% difference from the mean CO2 emissions factor for a given charging site among both marginal and average emissions factors and up to a 63% difference from the average across average emissions factors. Our results underscore the importance of method selection and the need for a consensus on approaches appropriate for particular loads and research questions being addressed in order to achieve results that are more consistent across studies and allow for soundly supported policy decisions. The paper addresses this issue by offering a set of recommendations for determining an appropriate model type on the basis of the load characteristics and study objectives. [ABSTRACT FROM AUTHOR]

Due to decreasing solar module prices, some solar developers are increasing their projects’ inverter loading ratio (ILR), defined as the ratio of DC module capacity to AC inverter capacity. In this study, we examine the operational impacts of this trend. Using minute-level solar data, we examine the relationship between inverter induced clipping losses and AC generation. We find minimal clipping losses at an ILR of 1.25; at an ILR of 2.0, we observe that 16% of potential annual generation is lost. Minute-level data prove to be essential in determining the generation lost to clipping, as hourly data mask key clipping and ramping events. Higher ILRs lead to a greater frequency of time spent at maximum generation, but also a greater frequency and magnitude of large solar ramping events. Module degradation can attenuate the impacts of inverter clipping over time. We observe that the effective degradation rate (net of any changes to inverter clipping losses) can be as little as half the actual degradation rate for projects with high ILRs. The diurnal and seasonal trends in clipping correspond with solar insolation patterns, with the highest clipping occurring around noon. For fixed tilt installations with tilt angles at latitude, we observe the highest clipping near the autumnal and vernal equinoxes. Increasing the tilt angle leads to more winter clipping, while lower tilt angles shifts the clipping to summer months. Shifting from fixed tilt to north–south single axis tracking increases the generation lost to clipping significantly. At an ILR of 1.25, annual clipping approximately doubles to 1% compared to fixed tilt at latitude, while clipping under an ILR of 2.0 increases to 22%, compared to 16% for the fixed configuration. As expected, more clipping occurs during the hours preceding and following noon when using single axis tracking. [ABSTRACT FROM AUTHOR]

We use the CAMx (Comprehensive Air Quality Model with Extensions) chemical transport model (CTM) with 4-km horizontal resolution over the Korean Peninsula to investigate source contributions to PM 2.5 in Korea from domestic and upwind sources. We modeled 2015 and 2016 to account for meteorological variation with Korean emissions from the Clean Air Policy Supporting System (CAPSS), meteorology from WRF (Weather, Research, and Forecasting) model, and regional boundary concentrations from the GEOS-Chem global CTM. The CAMx particulate source apportionment technology (PSAT) provided PM 2.5 source contributions from 5 source sectors and 6 geographic regions within Korea, international sources, and boundary concentrations. PM 2.5 contributions from outside Korea are important with boundary concentrations plus the "other" emissions sector (includes marine shipping, agricultural ammonia, and international emissions from North Korea and Japan within the CAMx domain) contributing 67% of annual average PM 2.5 in Seoul in 2016 and 71% in 2015. The boundary concentrations contributed between 30% and 50% of PM 2.5 at different Korean cities with contributions generally lower in 2016 than in 2015. For Korean sources, PM 2.5 contributions from Electric Generating Unit (EGU) emissions were smaller than contributions from mobile and industrial emissions sources although there is considerable day-to-day variation in contributions. On an annual basis in 2016, the "other" category contributed 25% followed by mobile sources at 23%, industrial sources at 6%, and EGU sources at 3%. For 2015, the contributions were similar. Focusing on March when PM 2.5 concentrations were higher than other months, the contributions from other, mobile, industrial, and EGUs were 21%, 18%, 4%, and 4%, respectively in 2016. For 2015, contributions from these four categories were 18%, 15%, 3%, and 3%, respectively. • A regional air quality model estimated domestic contributions from different sources and regions to PM2.5 in Korea. • Boundary conditions (includes contributions from China) contributed 30% to 50% towards PM2.5 in major cities in Korea. • Among the domestic sources, mobile sources contributed the most towards PM2.5 in Korea followed by the industrial sources. • Our results are qualitatively similar to previous source attribution studies of PM2.5 in Korea. [ABSTRACT FROM AUTHOR]

A 13 year-old girl with a congenital carotid–jugular fistula presented with a pulsatile mass and a thrill on the left side of her neck. Angiography showed a fistula between the left internal maxillary artery and the jugular vein. The patient underwent coil embolization using a transarterial balloon-assisted technique and one week later, a transvenous approach. The fistula was completely obliterated, and the patient’s symptoms resolved. [ABSTRACT FROM AUTHOR]

Changes in the coral reef complex can affect predator-prey relationships, resource availability and niche utilisation in the associated fish community, which may be reflected in decreased stability of the functional traits present in a community. This is because particular traits may be favoured by a changing environment, or by habitat degradation. Furthermore, other traits can be selected against because degradation can relax the association between fishes and benthic habitat. We characterised six important ecological traits for fish species occurring at seven sites across a disturbed coral reef archipelago in Indonesia, where reefs have been exposed to eutrophication and destructive fishing practices for decades. Functional diversity was assessed using two complementary indices (FRic and RaoQ) and correlated to important environmental factors (live coral cover and rugosity, representing local reef health, and distance from shore, representing a cross-shelf environmental gradient). Indices were examined for both a change in their mean, as well as temporal (short-term; hours) and spatial (cross-shelf) variability, to assess whether fish-habitat association became relaxed along with habitat degradation. Furthermore, variability in individual traits was examined to identify the traits that are most affected by habitat change. Increases in the general reef health indicators, live coral cover and rugosity (correlated with distance from the mainland), were associated with decreases in the variability of functional diversity and with community-level changes in the abundance of several traits (notably home range size, maximum length, microalgae, detritus and small invertebrate feeding and reproductive turnover). A decrease in coral cover increased variability of RaoQ while rugosity and distance both inversely affected variability of FRic; however, averages for these indices did not reveal patterns associated with the environment. These results suggest that increased degradation of coral reefs is associated with increased variability in fish community functional composition resulting from selective impacts on specific traits, thereby affecting the functional response of these communities to increasing perturbations. [ABSTRACT FROM AUTHOR]

Energy storage devices, such as batteries and flywheels, are promising options for providing operating reserves due to their fast response and low emissions during operation. However, because of the complex nature of power systems, adding energy storage-based reserves to the power system may not necessarily benefit the environment. In this paper, we analyze these impacts in a test system and identify important drivers that affect the environmental outcomes. Dispatch results are obtained by solving an optimal power flow (OPF) problem and are used to determine emissions. We find that the impacts of adding energy storage are highly case-dependent. In systems with high renewable penetration levels and significant renewable curtailment, adding energy storage reduces emissions; in other systems, the impacts on emissions could be positive, neutral, or negative. The analyses presented in this paper show that policies to procure energy storage as a means to reduce emissions may actually lead to increased system-wide emissions if current dispatch algorithms are used. We also explore the impacts of modifying the dispatch algorithm to ensure system emissions with energy storage are no worse than system emissions without energy storage. [ABSTRACT FROM AUTHOR]

The introduction of energy storage technologies to the grid could enable greater integration of renewables, improve system resilience and reliability, and offer cost effective alternatives to transmission and distribution upgrades. The integration of energy storage systems into the electrical grid can lead to different environmental outcomes based on the grid application, the existing generation mix, and the demand. Given this complexity, a framework is needed to systematically inform design and technology selection about the environmental impacts that emerge when considering energy storage options to improve sustainability performance of the grid. To achieve this, 12 fundamental principles specific to the design and grid application of energy storage systems are developed to inform policy makers, designers, and operators. The principles are grouped into three categories: (l) system integration for grid applications, (2) the maintenance and operation of energy storage, and (3) the design of energy storage systems. We illustrate the application of each principle through examples published in the academic literature, illustrative calculations, and a case study with an off-grid application of vanadium redox flow batteries (VRFBs). In addition, trade-offs that can emerge between principles are highlighted. [ABSTRACT FROM AUTHOR]

An examination of the environmental benefits of an expanded RPS in Michigan find that, with higher coal retirements, significantly more natural gas is displaced by the expanded RPS, thereby reducing the emissions mitigation potential. This illustrates how the environmental benefits of renewable energy are dependent on the system into which it is integrated. [ABSTRACT FROM AUTHOR]

We report a semiautomated synthesis of sequence and architecturally defined, unimolecular macromolecules through a marriage of multistep flow synthesis and iterative exponential growth (Flow-IEG). The Flow-IEG system performs three reactions and an in-line purification in a total residence time of under 10 min, effectively doubling the molecular weight of an oligomeric species in an uninterrupted reaction sequence. Further iterations using the Flow-IEG system enable an exponential increase in molecular weight. Incorporating a variety of monomer structures and branching units provides control over polymer sequence and architecture. The synthesis of a uniform macromolecule with a molecular weight of 4,023 g/mol is demonstrated. The user-friendly nature, scalability, and modularity of Flow-IEG provide a general strategy for the automated synthesis of sequence-defined, unimolecular macromolecules. Flow-IEG is thus an enabling tool for theory validation, structure–property studies, and advanced applications in biotechnology and materials science. [ABSTRACT FROM AUTHOR]

Localized impacts, such as eutrophication and overfishing, have been identified as major threats to reefs worldwide, resulting in changes in coral reef community composition, from coral-dominance to algal-dominance. Herbivory by fishes is frequently cited as a key process structuring benthic community response to stressors. Here, we experimentally tested the capacity of herbivorous fishes to remove macroalgae along an onshore-offshore spatial gradient in the Spermonde Archipelago, Indonesia; a coral reef system exposed to long-term anthropogenic disturbances. Bioassays of Sargassum and Padina spp. were collected from the reef flat and transplanted onto the reef slope at five islands varying in distance (1-55 km) from the coastline and city of Makassar, South Sulawesi. Supplementary underwater video deployment and fish surveys were used to identify species-specific differences in herbivore communities and rates of algal removal. Over a 24 h period, Padina was almost completely removed from the two outermost islands, but removal declined toward shore. With the exception of the site closest to Makassar, more than 50% of all transplanted macroalgae were removed. Species diversity of algal-consuming fishes and total bites increased toward off-shore, with only one species, Siganus virgatus (Siganidae), feeding at all sites. These changes in herbivore communities underline the capacity for functional resilience under varying levels of reef degradation. Our results exemplify the complexities of ecological functioning along environmental gradients. [ABSTRACT FROM AUTHOR]

Introduction Intractable hemorrhage of the nasal or oropharyngeal cavities can be life threatening, and endovascular embolization is one of the few effective treatments for severe recurrent bleeds. Traditionally, embolic particles have been used for transarterial embolization. Objective To investigate the safety and efficacy of a less commonly performed treatment--namely, feeding artery occlusion with liquid embolic agents. Methods We retrospectively reviewed our neurointerventional database for patients who had undergone transarterial embolization for intractable nasal and oropharyngeal hemorrhage with Onyx, N-butyl-2 cyanoacrylate (n-BCA) glue, or both, at our institution over a 5-year period from 2008 to 2013. Results Forty-six patients who underwent a total of 51 procedures met the inclusion criteria. Causes of hemorrhage included neoplasm n=35 (68.6%), trauma n=12 (23.5%), and idiopathic n=4 (7.9%). The bleeding was oropharyngeal in 66.7%, nasal in 29.4%, and 3.9% originated from both sites. Embolic agents used were n-BCA in 26 cases (51.0%), Onyx in 22 cases (43.1%), and both agents in three cases (5.9%). Mean total procedural time was 93.1 min (range 34-323 min), and mean fluoroscopy time was 39.1 min (10-121 min). Mean follow-up time was 7.4 months (0.25-36 months). Five of the 46 patients (10.9%) required re-embolization and one (2.0%) rebled during the same hospital stay. One periprocedural cardiovascular adverse event occurred that was unrelated to the embolic agent used, but no other complications were seen. Conclusions Transarterial embolization with n-BCA or Onyx is a safe and effective treatment for patients with intractable nasal and oropharyngeal hemorrhage. Further prospective studies are warranted to confirm these findings. [ABSTRACT FROM AUTHOR]

N-Heterocyclic carbenes (NHCs) have emerged as versatile ligands for surface functionalization. Their ease of synthesis and ability to form strong bonds with a range of substrates provide a unique complement to traditional surface modification methods. Gold nanoparticles (NPs) are a particularly useful class of materials whose applications intimately depend on surface functionalization. Here we report the development of PEGylated-NHC ligands for Au-NP surfaces and the first example of NHC-functionalized NPs that are compatible with biologically relevant conditions. Our PEGylated-NHC-Au-NPs are stable toward aggregation in aqueous solutions in the pH range of 3-14, in <250 mM electrolyte solutions, at high and low temperatures (95 and -78 °C), in cell culture media, and in aqueous H2O2 solutions. This work demonstrates for the first time that NHCs can serve as anchors for water-soluble Au-NPs and opens the door to potential biomedical applications of NHC surface anchors. [ABSTRACT FROM AUTHOR]

Energy storage may serve as a solution to the integration challenges of high penetrations of wind, helping to reduce curtailment, provide system balancing services, and reduce emissions. This study determines the minimum cost configuration of vanadium redox flow batteries (VRFB), wind turbines, and natural gas reciprocating engines in an off-grid model. A life cycle assessment (LCA) model is developed to determine the system configuration needed to achieve a variety of CO 2 -eq emissions targets. The relationship between total system costs and life cycle emissions are used to optimize the generation mixes to achieve emissions targets at the least cost and determine when VRFBs are preferable over wind curtailment. Different greenhouse gas (GHG) emissions targets are defined for the off-grid system and the minimum cost resource configuration is determined to meet those targets. This approach determines when the use of VRFBs is more cost effective than wind curtailment in reaching GHG emissions targets. The research demonstrates that while incorporating energy storage consistently reduces life cycle carbon emissions, it is not cost effective to reduce curtailment except under very low emission targets (190 g of CO2-eq/kW h and less for the examined system). This suggests that “overbuilding” wind is a more viable option to reduce life cycle emissions for all but the most ambitious carbon mitigation targets. The findings show that adding VRFB as energy storage could be economically preferable only when wind curtailment exceeds 66% for the examined system. The results were most sensitive to VRFB costs, natural gas upstream emissions (e.g. methane leakage), and wind capital cost. [ABSTRACT FROM AUTHOR]

In the United States, state-level Renewable Portfolio Standards (RPS) have served as key drivers for the development of new renewable energy. This research presents a method to evaluate emissions reductions and costs attributable to new or expanded RPS programs by integrating a comprehensive economic dispatch model and a renewable project selection model. The latter model minimizes incremental RPS costs, accounting for renewable power purchase agreements (PPAs), displaced generation and capacity costs, and net changes to a state's imports and exports. We test this method on potential expansions to Michigan's RPS, evaluating target renewable penetrations of 10% (business as usual or BAU), 20%, 25%, and 40%, with varying times to completion. Relative to the BAU case, these expanded RPS policies reduce the CO2 intensity of generation by 13%, 18%, and 33% by 2035, respectively. SO2 emissions intensity decreased by 13%, 20%, and 34% for each of the three scenarios, while NOx reductions totaled 12%, 17%, and 31%, relative to the BAU case. For CO2 and NOx, absolute reductions in emissions intensity were not as large due to an increasing trend in emissions intensity in the BAU case driven by load growth. Over the study period (2015 to 2035), the absolute CO2 emissions intensity increased by 1% in the 20% RPS case and decreased by 6% and 22% for the 25% and 40% cases, respectively. Between 26% and 31% of the CO2, SO2, and NOx emissions reductions attributable to the expanded RPS occur in neighboring states, underscoring the challenges quantifying local emissions reductions from state-level energy policies with an interconnected grid. Without federal subsidies, the cost of CO2 mitigation using an RPS in Michigan is between $28 and $34/t CO2 when RPS targets are met. The optimal renewable build plan is sensitive to the capacity credit for solar but insensitive to the value for wind power. [ABSTRACT FROM AUTHOR]

Herein, we report simple flow reactor designs that enable photo-controlled living radical polymerization (photo-CRP) from trithiocarbonates (TTCs) with significant enhancements in scalability and reaction rates compared to the analogous batch reactions. We also demonstrate the “on/off” photo-switchability of this reaction under flow conditions. [ABSTRACT FROM AUTHOR]

Certain weight-based orders on the free associative algebra R = k 〈 x 1 , … , x t 〉 can be specified by t × ∞ arrays whose entries come from the subring of positive elements in a totally ordered field. If such an array satisfies certain additional conditions, it produces a partial order on R which is an admissible order on the quotient R / I , where the ideal I is a homogeneous binomial ideal called the weight ideal associated to the array. The structure of the weight ideal is determined entirely by the array. This article discusses the structure of the weight ideals associated to two distinct types of arrays which define admissible orders on the associated quotient algebra. [ABSTRACT FROM AUTHOR]

We report a rare case of a renal cell carcinoma (RCC) metastasis occupying the cerebellopontine and cerebellomedullary cisterns, and describe an alternative strategy for embolizing hypervascular intracranial tumors. A middle aged patient with a distant history of RCC presented with headaches, nausea, and vomiting, and was found to have an enhancing mass in the left cerebellopontine and cerebellopontine cisterns. The initial surgical resection was aborted due to excessive bleeding. After an unsuccessful attempt at intra-arterial embolization, the patient returned to the operating room and the tumor was devascularized by direct needle puncture Onyx embolization under biplane fluoroscopy. The devascularized tumor was then successfully dissected from the brainstem and adherent lower cranial nerves. In properly selected cases, open surgical direct needle puncture embolization of intracranial vascular tumors under biplane fluoroscopy is a viable alternative devascularization method. [ABSTRACT FROM AUTHOR]

Objective: The incidence of acute ischemic stroke is highest in the elderly. Information regarding outcomes of elderly patients undergoing different modalities of intra-arterial therapy (IAT) for acute ischemic stroke (AIS) is scarce and conflicting. This study compares the safety, technical efficacy and outcomes of elderly patients (≥ years) to non-elderly patients (<80 years) who underwent multimodality IAT. Methods: From a registry of consecutive patients treated with IAT for AIS at our institution over a 3.5-year period, patients with anterior circulation occlusions aged ≥80 years were compared to the patients <80 years. Results: Between 2008 and 2012, 24 patients ≥80 years (elderly) and 95 patients <80 years (non-elderly) received IAT for anterior circulation occlusions. In the elderly, there were more females (66.7% vs. 28.4%, p = <0.001) and atrial fibrillation (58.3% vs. 25.2%, p = 0.003). Between the 2 groups, there was no difference in NIHSS score (17.2 vs.16.3, p = 0.17), THRIVE score (4.21 vs. 4.39, p = 0.633), recanalization rate (70.1% vs. 85.3%, p = 0.13), or severe reperfusion hemorrhages (8.3% vs. 4.2%, p = 0.425). There was no significant difference in 3-month mortality (33.3% vs. 16.8%, p = 0.28); however, fewer elderly patients reached good 3-month outcome (0% vs. 40.0%, p = <0.001). After controlling for baseline factors, only female gender (OR 5.3, 95% CI 1.7-16.7; p = 0.04) and higher 3-month mRS (OR 1.6; 95% CI 1.1-2.40; p = 0.008) were independently associated with elderly age. Conclusion: Despite similar safety profiles and recanalization rates, elderly patients had poor functional outcomes after IAT. Intra-arterial therapy in the elderly should be pursued very cautiously only after careful analysis of the risks and benefits for each patient. [ABSTRACT FROM AUTHOR]

Highlights: [•] We assess the potential for energy storage to economically decrease wind curtailment or decrease system costs. [•] We assume that the wind is under contract via a power purchase agreement. [•] Maximum viable energy storage costs were $780/kW with ten hours of storage capacity. [•] Sizing the energy storage to reduce a small portion of curtailment supports higher unit cost batteries. [•] Significant curtailment persists even with high capacity energy storage. [Copyright &y& Elsevier]

The article presents a case study of a five-and-a-half-year-old boy who was diagnosed with pediatric coronoid fracture. Discussed are results of the magnetic resonance imaging (MRI) depicting a cartilaginous coronoid fragment. Mentioned is the reduction of the coronoid cartilaginous fragment as well as the anatomic reconstruction of the elbow.

Campylobacter jejuni is a leading cause of gastrointestinal infections worldwide, due primarily to its ability to asymptomatically colonize the gastrointestinal tracts of agriculturally relevant animals, including chickens. Infection often occurs following consumption of meat that was contaminated by C. jejuni during harvest. Because of this, much interest lies in understanding the mechanisms that allow C jejuni to colonize the chicken gastrointestinal tract. To address this, we generated a C. jejuni transposon mutant library that is amenable to insertion sequencing and introduced this mutant pool into day-of-hatch chicks. Following deep sequencing of C. jejuni mutants in the cecal outputs, several novel factors required for efficient colonization of the chicken gastrointestinal tract were identified, including the predicted outer membrane protein MapA. A mutant strain lacking mapA was constructed and found to be significantly reduced for chicken colonization in both competitive infections and monoinfections. Further, we found that mapA is required for in vitro competition with wild-type C. jejuni hut is dispensable for growth in monoculture. [ABSTRACT FROM AUTHOR]

The Community Multiscale Air Quality (CMAQ) modeling system Version 5.0 (CMAQv5.0) was released by the U.S. Environmental Protection Agency (EPA) in February 2012, with an interim release (v5.01) in July 2012. Because CMAQ is a community model, the EPA encourages the development of proven alternative science treatments by external scientists and developers that can be incorporated as part of an official CMAQ release. This paper describes the implementation, evaluation, and testing of a plume-in-grid (PinG) module in CMAQ 5.01. The PinG module, also referred to as Advanced Plume Treatment (APT), provides the capability of resolving sub-grid-scale processes, such as the transport and chemistry of point-source plumes, in a grid model. The new PinG module in CMAQ 5.01 is applied and evaluated for two 15-day summer and winter periods in 2005 to the eastern United States, and the results are compared with those from the base CMAQ 5.01. Eighteen large point sources of NOx in the eastern United States were selected for explicit plume treatment with APT in the PinG simulation. The results show that overall model performance is negligibly affected when PinG treatment is included. However, the PinG model predicts significantly different contributions of the 18 sources to pollutant concentrations and deposition downwind of the point sources compared to the base model.Implications: This study describes the incorporation of a plume-in-grid (PinG) capability within the latest version of the EPA grid model, CMAQ. The capability addresses the inherent limitation of the grid model to resolve processes, such as the evolution of point-source plumes, which occur at scales much smaller than the grid resolution. The base grid model and the PinG version predict different source contributions to ozone and PM2.5 concentrations that need to be considered when source attribution studies are conducted to determine the impacts of large point sources on downwind concentrations and deposition of primary and secondary pollutants. [ABSTRACT FROM AUTHOR]

Evaluators have an obligation to present clearly the results of their evaluative efforts. Traditionally, such presentations showcase formal written and oral reports, with dispassionate language and graphs, tables, quotes, and vignettes. These traditional forms do not reach all audiences nor are they likely to include the most powerful presentation possibilities. In this article, we share our use of alternative presentation formats, undertaken to increase the utility, appeal, and salience of our work. We offer a conceptual rationale for the use of “alternative representational forms” and describe the context for our use of alternative formats, which involved evaluations of various science, technology, engineering, and mathematics (STEM) educational programs. We present four examples, featuring visual display, performance, multiple program theories, and poetry. The article concludes with reflections on the future of alternative presentation approaches. [ABSTRACT FROM AUTHOR]

Life cycle assessment practitioners struggle to accurately allocate environmental burdens of metals recycling, including the temporal dimension of environmental impacts. We analyze four approaches for calculating aluminum greenhouse gas emissions: the recycled content (RC) or cut-off approach, which assumes that demand for recycled content displaces primary production; end-of-life recycling (EOLR), which assumes that postuse recycling displaces primary production; market-based (MB) approaches, which estimate changes in supply and demand using price elasticities; and value-corrected substitution (VCS), which allocates impact based on price differences between primary and recycled material. Our analysis suggests that applications of the VCS approach do not adequately account for the changing scrap to virgin material price ratio over time, whereas MB approaches do not address stock accumulation and depletion. The EOLR and RC approaches were analyzed using two case studies: U.S. aluminum beverage cans and vehicle engine blocks. These approaches produced similar results for beverage cans, which have a closed material loop system and a short product life. With longer product lifetimes, as noted with the engine blocks, the magnitude and timing of the emissions differs greatly between the RC and EOLR approaches. The EOLR approach indicates increased impacts at the time of production, offset by negative impacts in future years, whereas the RC approach assumes benefits to increased recycled content at the time of production. For vehicle engine blocks, emissions using EOLR are 140% higher than with RC. Results are highly sensitive to recycled content and future recycling rates, and the choice of allocation methods can have significant implications for life cycle studies. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 61-year-old woman with isolated visual loss involving her left eye over a 3-month period. She underwent magnetic resonance image (MRI) of the brain which diagnosed a giant left supraclinoid internal carotid artery (ICA) aneurysm and her left eye examination revealed optic atrophy. It mentions that balloon test occlusion of the left ICA was performed for the treatment of aneurysm.

Growing pores: Exposure of a bis‐norbornene trithiocarbonate to long‐wavelength UV light, or sunlight, in the presence of N‐isopropylacrylamide (NiPAAm) led to well‐defined norbornene–telechelic poly(NiPAAm) macromers. The macromers were end‐linked with a tris‐tetrazine via inverse‐electron‐demand Diels–Alder cycloaddition to generate polymer gels. Addition of new monomer, followed by exposure to sunlight, led to “photo‐growth” of the network pores. [ABSTRACT FROM AUTHOR]