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OBJECTIVE: To explore the culture, beliefs, values, customs and practices around the birth process within a free-standing birth centre (FSBC). DESIGN: Ethnography. SETTING: A birth centre situated in the midlands of England. PARTICIPANTS: Women attending the centre, midwives and maternity-care assistants (MCAs) working at the centre. FINDINGS: Women in the study seemed to invoke intuitive nesting-related behaviours in their assessment of the suitability of the birth centre. In addition, the birth centre staff's focus on creating the right ambience for birth may also emanate from nesting concerns. Birth-centre staff assisted women through the 'becoming mother' transition, which is conceptualised as 'matrescent' care. KEY CONCLUSIONS: The birth-centre environment elicited nesting-like behaviours from both women and staff. This formed part of a nurturing orientation that was conceptualised as 'matrescent' (becoming mother) care. 'Matrescence' does not seem to be grounded in clinical skills but is relationally mediated. IMPLICATIONS FOR PRACTICE: Nesting-like behaviours and 'matrescent' care in this context challenge maternity services to review traditional conceptualisations of safety and traditional expressions of clinical intrapartum care. [ABSTRACT FROM AUTHOR]

Background: This study sought to describe patient features before beginning fertility treatment, and to ascertain their perceptions relative to risk of twin pregnancy outcomes associated with such therapy. Methods: Data on readiness for twin pregnancy outcome from in vitro fertilisation (IVF) was gathered from men and women before initiating fertility treatment by anonymous questionnaire. Results: A total of 206 women and 204 men were sampled. Mean (± SD) age for women and men being 35.5 ± 5 and 37.3 ± 7 yrs, respectively. At least one IVF cycle had been attempted by 27.2% of patients and 33.9% of this subgroup had initiated >3 cycles, reflecting an increase in previous foiled cycles over five years. Good agreement was noted between husbands and wives with respect to readiness for twins from IVF (77% agreement; Cohen's K = 0.61 ; 95% CI 0.53 to 0.70). Conclusion: Most patients contemplating IVF already have ideas about particular outcomes even before treatment begins, and suggests that husbands & wives are in general agreement on their readiness for twin pregnancy from IVF. However, fertility patients now may represent a more refractory population and therefore carry a more guarded prognosis. Patient preferences identified before IVF remain important, but further studies comparing pre- and post-treatment perceptions are needed. [ABSTRACT FROM AUTHOR]

Purpose: Acute ischemic stroke is a leading cause of death and morbidity worldwide. Despite advances in medical technology, nearly 30% of strokes result in incomplete vessel recanalization. Recent studies have demonstrated that clot composition correlates with success rates of mechanical thrombectomy procedures. To understand clot behavior during thrombectomy, which exerts considerable strains on thrombi, in vitro studies must characterize the rate-dependent high-strain behavior of embolus analogs (EAs) with different formation conditions, which can be used to fit models of hyper-viscoelasticity., Methods: In this study, the effect of collagen infiltration as a carotid-induced collagen-rich thrombosis surrogate is considered as a contributor to embolus analog high-strain stiffness, when compared to 40% hematocrit EAs., Results: EA high-strain stiffnesses, characterized on a uniaxial load frame, increase by an order of magnitude for collagenous clot analogs. Chandler loop analogs show high-strain stiffnesses and clot compositions commensurate with previous reports of stroke patient clots, and collagenous clots show significant increase in stiffness when compared to stroke patient clots. Finally, hyper-viscoelastic curve fitting demonstrates the asymmetry between tension and compression. Nonlinear, rate-dependent models that consider clot-stiffening behavior match the high strain stiffness of clots fairly well. Furthermore, we demonstrate that the stability of the elastic energy needs to be considered to obtain optimal curve fits for high-strain, rate dependent data., Conclusion: This study provides a framework for the development of dynamically formed EAs that mimic the mechanical and structural properties of in vivo clots and provides parameters for numerical simulation of clot behavior with hyper-viscoelastic models., Competing Interests: Declaration of competing interest K.B.M. has a financial interest in Cranial Devices, Inc., a company which could potentially benefit from the results of the presented research. The interest has been reviewed and is being managed by The Pennsylvania State University in accordance with its individual conflict of interest policy, for the purpose of maintaining the objectivity of research at The Pennsylvania State University. All other authors indicate no conflict associated with this research., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Choline contributes to the biogenesis of methyl groups, neurotransmitters, and cell membranes. Our genome-wide association study (GWAS) of circulating choline in 2228 college students found that alleles in SLC25A48 (rs6596270) influence choline concentrations in men (p = 9.6 × 10 -8 ), but not women. Previously, the subcellular location and function of SLC25A48 were unknown. Using super-resolution immunofluorescence microscopy, we localized SLC25A48 to the inner mitochondrial membrane. Our results suggest that SLC25A48 transports choline across the inner mitochondrial membrane., Competing Interests: Declaration of competing interest The authors have no competing interests to declare., (Published by Elsevier Inc.)

Background: Geriatric Oncology is a specialty where a multidisciplinary approach can address the unmet needs of older adults with cancer. Older adults are at increased risk of adverse drug events (ADE) due to age-related changes in pharmacokinetics and pharmacodynamics, increasing treatment complexity, and medication burden., Objectives: To review the literature to determine the incidence of unplanned hospitalisation due to ADE for all medications, both systemic anticancer therapy (SACT) and non-SACT medications., Methods: A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. The search included the following databases: PubMed, CINAHL, and Embase. A manual search of Scopus was then performed. Study quality was assessed using the Cochrane Handbook for Systematic Reviews of Interventions, Mixed Methods Appraisal Tool (MMAT) and Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework., Results: Overall, three studies were included. One observational study reported 19 % of unplanned hospital admissions due to ADE in patients aged ≥70 years with cancer. The first retrospective study reported 24 % of unplanned hospital admissions are due to ADE in patients aged ≥70 years with cancer, and the second retrospective study reported 26 % of patients with metastatic melanoma treated with immune checkpoint inhibitors had an unplanned hospital admission due to an ADE., Conclusion: There is a paucity of studies assessing unplanned hospitalisation due to ADE in older adults with cancer. Future studies are needed and should account for the reporting of potential ADE relative to supportive care, ancillary medications, and indeed chronic medications used to treat long-standing comorbidities., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Most cases of human prion disease arise due to spontaneous misfolding of WT or mutant prion protein, yet recapitulating this event in animal models has proven challenging. It remains unclear whether spontaneous prion generation can occur within the mouse lifespan in the absence of protein overexpression and how disease-causing mutations affect prion strain properties. To address these issues, we generated knockin mice that express the misfolding-prone bank vole prion protein (BVPrP). While mice expressing WT BVPrP (I109 variant) remained free from neurological disease, a subset of mice expressing BVPrP with mutations (D178N or E200K) causing genetic prion disease developed progressive neurological illness. Brains from spontaneously ill knockin mice contained prion disease-specific neuropathological changes as well as atypical protease-resistant BVPrP. Moreover, brain extracts from spontaneously ill D178N- or E200K-mutant BVPrP-knockin mice exhibited prion seeding activity and transmitted disease to mice expressing WT BVPrP. Surprisingly, the properties of the D178N- and E200K-mutant prions appeared identical before and after transmission, suggesting that both mutations guide the formation of a similar atypical prion strain. These findings imply that knockin mice expressing mutant BVPrP spontaneously develop a bona fide prion disease and that mutations causing prion diseases may share a uniform initial mechanism of action.

Both randomized controlled trials (RCTs) and retrospective studies have shown that a comprehensive geriatric assessment (CGA) prior to a patient commencing systemic anti-cancer therapy (SACT) results in improved quality of life outcomes and is associated with a decreased risk of grade 3-5 toxicity; however, data are lacking in relation to adverse drug events (ADE) associated with supportive care medications. Supportive care medications are prescribed as prophylactic agents in a SACT regimen, for management of treatment related toxicity and for symptoms caused by the disease itself. While necessary, the commencement of SACT and supportive medications may cause, or exacerbate, a significant drug burden in older patients, some of whom may have existing comorbidities. For many medications, older adults are underrepresented in pharmacokinetic and pharmacodynamic modelling studies. In this article we will review ageing-related changes in pharmacokinetics and pharmacodynamics, as well as how these changes may impact supportive care medications. Additional considerations for prescribing these medications in older adults with cancer, such as polypharmacy, potentially inappropriate medications, drug-drug interactions, and anticholinergic burden, as well as ageing-related considerations and recommendations for supportive care medications commonly used in older adults with cancer are also reviewed., Competing Interests: Declaration of Competing Interest None to declare., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Staphylococcus aureus has the ability to invade cortical bone osteocyte lacuno-canalicular networks (OLCNs) and cause osteomyelitis. It was recently established that the cell wall transpeptidase, penicillin-binding protein 4 (PBP4), is crucial for this function, with pbp4 deletion strains unable to invade OLCNs and cause bone pathogenesis in a murine model of S. aureus osteomyelitis. Moreover, PBP4 has recently been found to modulate S. aureus resistance to β-lactam antibiotics. As such, small molecule inhibitors of S. aureus PBP4 may represent dual functional antimicrobial agents that limit osteomyelitis and/or reverse antibiotic resistance. A high throughput screen recently revealed that the phenyl-urea 1 targets PBP4. Herein, we describe a structure-activity relationship (SAR) study on 1. Leveraging in silico docking and modeling, a set of analogs was synthesized and assessed for PBP4 inhibitory activities. Results revealed a preliminary SAR and identified lead compounds with enhanced binding to PBP4, more potent antibiotic resistance reversal, and diminished PBP4 cell wall transpeptidase activity in comparison to 1., (© 2024 John Wiley & Sons Ltd.)

Purpose: Obesity is an epidemic which increases risk of many surgical procedures. Previous studies in spine and hip arthroplasty have shown that fat thickness measured on preoperative imaging may be as or more reliable in assessment of risk of post-operative infection and/or wound complications than body mass index (BMI). We hypothesized that, similarly, increased local fat thickness at the surgical site is a predictor of wound complication in acetabulum fracture surgery., Methods: Patients who underwent open reduction and internal fixation (ORIF) of an acetabulum fracture through a Kocher-Langenbeck (K-L) approach at a single institution from 2013 to 2020 were identified. Pre-operative CT scans were used to measure fat thickness from the skin to the greater trochanter in line with the surgical approach. Post-operative infections and wound complications were recorded and associated with fat thickness and BMI., Results: 238 patients met inclusion criteria. 12 patients had either infection or a wound complication (5.0%). There was no significant association with BMI or preoperative fat thickness on post-operative infection or wound complication (p-value 0.73 and 0.86)., Conclusions: There is no statistically significant association of post-operative infection or wound complications in patients with increased soft tissue thickness or increased BMI. ORIF of acetabulum fractures through a K-L approach can be performed safely in patients with large subcutaneous fat thickness and high BMI with low risk of infection or wound complications., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Prion diseases uniquely manifest in three distinct forms: inherited, sporadic, and infectious. Wild-type prions are responsible for the sporadic and infectious versions, while mutant prions cause inherited variants like fatal familial insomnia (FFI) and familial Creutzfeldt-Jakob disease (fCJD). Although some drugs can prolong prion incubation times up to four-fold in rodent models of infectious prion diseases, no effective treatments for FFI and fCJD have been found. In this study, we evaluated the efficacy of various anti-prion drugs on newly-developed knock-in mouse models for FFI and fCJD. These models express bank vole prion protein (PrP) with the pathogenic D178N and E200K mutations. We applied various drug regimens known to be highly effective against wild-type prions in vivo as well as a brain-penetrant compound that inhibits mutant PrPSc propagation in vitro. None of the regimens tested (Anle138b, IND24, Anle138b + IND24, cellulose ether, and PSCMA) significantly extended disease-free survival or prevented mutant PrPSc accumulation in either knock-in mouse model, despite their ability to induce strain adaptation of mutant prions. Our results show that anti-prion drugs originally developed to treat infectious prion diseases do not necessarily work for inherited prion diseases, and that the recombinant sPMCA is not a reliable platform for identifying compounds that target mutant prions. This work underscores the need to develop therapies and validate screening assays specifically for mutant prions, as well as anti-prion strategies that are not strain-dependent., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Walsh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Introduction: The increase in statin use, since their introduction, has been rapid and the broadening of indications has occurred seemingly without restriction. Once established on statin therapy, there is sparse research on discontinuation. Trials do not often address benefit in later life, or the impact of a life-limiting diagnosis. Data on primary prevention suggest that 100 patients need treatment for 2.5 years to prevent one major adverse cardiovascular event. Acknowledging this, we sought to determine the use of statins in a cohort of older adults with cancer, to highlight prevalence, and suggest a role for deprescribing., Materials and Methods: Data were retrospectively collected from a prospectively maintained database of patients attending a single centre Geriatric Oncology clinic. Data collected included sex, age, cancer type and stage, systemic anti-cancer therapy (SACT) recommendation, comorbidities, non-SACT medications, and overall survival. For those receiving statin therapy, data were separated into primary prevention and stage IV cancer., Results: In the group studied (n = 230), 135 (59%) were prescribed a statin, with 79 (58%) for primary prevention. Ninety-three (40%) had stage IV cancer. Of the 230 patients, 134 (58%) were recommended SACT. Within the primary prevention group, the median age was 79 years. Twenty-seven patients (34%) had stage III disease, while 36 (46%) had stage IV disease. Thirteen (16%) had diabetes mellitus. The median number of medications was seven (Interquartile range 5). Fifty patients (63%) were recommended SACT. In terms of survival, 31 (50%) were alive at one year, 18 (29%) alive at two years, and 14 (23%) alive beyond two and a half years. Within the stage IV disease group, 59 out of 93 (63%) were receiving statin therapy; 35 (59%) for primary prevention and seven (8%) for diabetes mellitus. Fifty-eight (63%) were recommended SACT. Twenty-four (29%) were alive at one year, 17 (21%) alive at two years, and 13 (16%) alive beyond two and a half years., Discussion: Statin therapy is prevalent and continues into older age. Available data regarding statin therapy in older adults and survival seen in this study support deprescribing in primary prevention and life-limiting illness, such as stage IV cancer., Competing Interests: Declaration of Competing Interest The authors have no declarations of competing interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

One-carbon metabolism is a complex network of metabolic reactions that are essential for cellular function including DNA synthesis. Vitamin B12 and folate are micronutrients that are utilized in this pathway and their deficiency can result in the perturbation of one-carbon metabolism and subsequent perturbations in DNA replication and repair. This effect has been well characterized in nuclear DNA but to date, mitochondrial DNA (mtDNA) has not been investigated extensively. Mitochondrial variants have been associated with several inherited and age-related disease states; therefore, the study of factors that impact heteroplasmy are important for advancing our understanding of the mitochondrial genome's impact on human health. Heteroplasmy studies require robust and efficient mitochondrial DNA enrichment to carry out in-depth mtDNA sequencing. Many of the current methods for mtDNA enrichment can introduce biases and false-positive results. Here, we use a method that overcomes these limitations and have applied it to assess mitochondrial heteroplasmy in mouse models of altered one-carbon metabolism. Vitamin B12 deficiency was found to cause increased levels of mitochondrial DNA heteroplasmy across all tissues that were investigated. Folic acid supplementation also contributed to elevated mitochondrial DNA heteroplasmy across all mouse tissues investigated. Heteroplasmy analysis of human data from the Framingham Heart Study suggested a potential sex-specific effect of folate and vitamin B12 status on mitochondrial heteroplasmy. This is a novel relationship that may have broader consequences for our understanding of one-carbon metabolism, mitochondrial-related disease and the influence of nutrients on DNA mutation rates., (Published by Oxford University Press on behalf of National Academy of Sciences 2024.)

Biosynthetic engineering of bicyclic darobactins, selectively sealing the lateral gate of the outer membrane protein BamA, leads to active analogues, which are up to 128-fold more potent against Gram-negative pathogens compared to native counterparts. Because of their excellent antibacterial activity, darobactins represent one of the most promising new antibiotic classes of the past decades. Here, we present a series of structure-driven biosynthetic modifications of our current frontrunner, darobactin 22 ( D22 ), to investigate modifications at the understudied positions 2, 4, and 5 for their impact on bioactivity. Novel darobactins were found to be highly active against critical pathogens from the WHO priority list. Antibacterial activity data were corroborated by dissociation constants with BamA. The most active derivatives D22 and D69 were subjected to ADMET profiling, showing promising features. We further evaluated D22 and D69 for bioactivity against multidrug-resistant clinical isolates and found them to have strong activity.

Introduction: Medication reconciliation as part of a Comprehensive Geriatric Assessment by a specialist pharmacist is a process that has been shown to be beneficial in terms of medication adherence in patients taking oral anticancer medication and potentially cost-effective in cancer patients. Medication review guidelines in older adults with cancer suggest using polypharmacy (≥ 5 medications) as an indication for medication review in older adults with cancer., Case Report: We present a case where a medication review as part of a Comprehensive Geriatric Assessment in the absence of polypharmacy resulted in two pharmacist interventions when standard care resulted in no intervention. A 71-year-old male prescribed capecitabine for rectal cancer had a medication reconciliation done as standard care before starting an oral anticancer medication. He then proceeded to get a medication review as part of a Comprehensive Geriatric Assessment and was deemed to have a potentially excessive anticholinergic burden and underprescribed gastro protection. This case is interesting as it occurred in a patient who would not have met the current inclusion criteria for a medication review as part of a Comprehensive Geriatric Assessment., Management and Outcome: As a result of the Comprehensive Geriatric Assessment, a letter was written to the patient's general practitioner, recommending a change to anti-depressant therapy to optimise anticholinergic burden, as well as introducing a proton-pump inhibitor upon completion of the Capecitabine protocol concurrent with radiotherapy, to confer gastro-protection against the antidepressant medication, as per the START criteria. Upon discharge from medical oncology, neither of the changes had been adopted by the patient's general practitioner. This highlights one of the challenges facing clinical pharmacists in an outpatient setting, where evidence-based recommendations are not always implemented as care transitions from tertiary to primary care., Conclusion: Comprehensive Geriatric Assessment is a process that identifies potential issues in older adults with cancer that aren't identified with standard medication review. This is also evident for medication reviews as part of a Comprehensive Geriatric Assessment, and where resources allow, and recommendations are likely to be accepted, it should be offered to all older adults with cancer. Pharmacists are still faced with challenges in implementing recommendations from medication reviews, particularly in healthcare systems where pharmacist prescribing has yet to be introduced., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Cofactor molecules are required to generate infectious mammalian prions in vitro. Mouse and hamster prions appear to have different cofactor preferences: Whereas both mouse and hamster prions can use phosphatidylethanolamine (PE) as a prion cofactor, only hamster prions can also use single-stranded RNA as an alternative cofactor. Here, we investigated the effect of detergent solubilization on rodent prion formation in vitro. We discovered that detergents that can solubilize PE (n-octylglucoside, n-octylgalactoside, and CHAPS) inhibit mouse prion formation in serial protein misfolding cyclic amplification (sPMCA) reactions using bank vole brain homogenate substrate, whereas detergents that are unable to solubilize PE (Triton X-100 and IPEGAL) have no effect. For all three PE-solubilizing detergents, inhibition of RML mouse prion formation was only observed above the critical micellar concentration (CMC). Two other mouse prion strains, Me7 and 301C, were also inhibited by the three PE-solubilizing detergents but not by Triton X-100 or IPEGAL. In contrast, none of the detergents inhibited hamster prion formation in parallel sPMCA reactions using the same bank vole brain homogenate substrate. In reconstituted sPMCA reactions using purified substrates, n-octylglucoside inhibited hamster prion formation when immunopurified bank vole PrP C substrate was supplemented with brain phospholipid but not with RNA. Interestingly, phospholipid cofactor solubilization had no effect in sPMCA reactions using bacterially expressed recombinant PrP substrate, indicating that the inhibitory effect of solubilization requires PrP C post-translational modifications. Overall, these in vitro results show that the ability of PE to facilitate the formation of native but not recombinant prions requires phospholipid bilayer integrity, suggesting that membrane structure may play an important role in prion formation in vivo., (© 2023 International Society for Neurochemistry.)

Introduction: Geriatric oncology is a rapidly evolving field of practice, where comprehensive geriatric assessments (CGA) and multidisciplinary team (MDT) input have the potential to improve patient outcomes. Polypharmacy and potential drug interactions (PDI) have been associated with an increased risk of adverse outcomes in older adults with cancer, receiving systemic anti-cancer therapy (SACT). Our aim was to assess the incidence of unplanned hospitalization in older adults with cancer attending medical oncology outpatient clinics and to determine whether an unplanned hospitalization was potentially due to an adverse drug event (ADE)., Materials and Methods: We identified patients who attended a medical oncology outpatient appointment from January 1 to March 31, 2018. Medical records were examined to identify any unplanned hospital admissions between the clinic visit date and three and six months after initial clinic visit. Incidences of unplanned hospitalization were assessed to determine if an ADE potentially occurred., Results: Data collected from 174 patients were analyzed. Over half (57%) were female, median age was 75 years and 53% had a favorable performance status. The most common malignancies were gastrointestinal (GI) at 31% (n = 54), breast 29% (n = 51), and genitourinary 22% (n = 37). Seventy-two percent had advanced disease (stage III/IV) and 61% had systemic therapy (SACT and hormonal therapy). Polypharmacy (≥5 medications) was observed in 77% of patients. The total number of admissions at six months was 99, with 55% of these potentially due to an ADE. On multivariate analysis breast cancer (p ≤0.001), lung cancer (p = 0.034), performance status (p ≤0.001), monochemotherapy (p = 0.012), polychemotherapy (p ≤0.001), and radiotherapy (p = 0.048) were independent predictors of unplanned hospitalization. Breast cancer (p = 0.008), GI cancer (p = 0.019), monochemotherapy (p = 0.039), and polychemotherapy (p ≤0.001) were independent predictors of unplanned hospitalization due to ADE on multivariate analysis., Discussion: We observed that older adults with cancer have a high risk of unplanned hospitalization due to ADE. Medication review as part of a CGA in newly diagnosed older adults with cancer by a clinical pharmacist is recommended. This may identify opportunities to avoid medications that could potentially lead to unplanned hospitalization., Competing Interests: Declaration of Competing Interest The authors have no conflicts to declare., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Ovarian cancer is the sixth leading cause of cancer-related death in women, and both occurrence and mortality are increased in women over the age of 60. There are documented age-related changes in the ovarian cancer microenvironment that have been shown to create a permissive metastatic niche, including the formation of advanced glycation end products, or AGEs, that form crosslinks between collagen molecules. Small molecules that disrupt AGEs, known as AGE breakers, have been examined in other diseases, but their efficacy in ovarian cancer has not been evaluated. The goal of this pilot study is to target age-related changes in the tumor microenvironment with the long-term aim of improving response to therapy in older patients. Here, we show that AGE breakers have the potential to change the omental collagen structure and modulate the peritoneal immune landscape, suggesting a potential use for AGE breakers in the treatment of ovarian cancer.

The consistent rise of plastic pollution has stimulated interest in the development of biodegradable plastics. However, the study of polymer biodegradation has historically been limited to a small number of polymers due to costly and slow standard methods for measuring degradation, slowing new material innovation. High-throughput polymer synthesis and a high-throughput polymer biodegradation method are developed and applied to generate a biodegradation dataset for 642 chemically distinct polyesters and polycarbonates. The biodegradation assay was based on the clear-zone technique, using automation to optically observe the degradation of suspended polymer particles under the action of a single Pseudomonas lemoignei bacterial colony. Biodegradability was found to depend strongly on aliphatic repeat unit length, with chains less than 15 carbons and short side chains improving biodegradability. Aromatic backbone groups were generally detrimental to biodegradability; however, ortho- and para-substituted benzene rings in the backbone were more likely to be degradable than metasubstituted rings. Additionally, backbone ether groups improved biodegradability. While other heteroatoms did not show a clear improvement in biodegradability, they did demonstrate increases in biodegradation rates. Machine learning (ML) models were leveraged to predict biodegradability on this large dataset with accuracies over 82% using only chemical structure descriptors.

Competing Interests: Declaration of Competing Interest Maria-Estela Moreno-Martinez reports receiving honoraria from GSK SA, Gilead, EISAI, Roche Farma SA, Celgene SLU, Sanofi, Pfizer, Kyowa, and Daiichi Sankyo España, as well as travel support from Gilead. She also serves on boards for Incyte, AstraZeneca, Daiichi Sankyo España SAU, Salud Advisory Partners SL, Janssen-Cilag SA, Celgene SLU, Bayer, EISAI, HARMON Corporate Affiars SL, and Takeda and holds leadership/fiduciary roles in GEDEFO-SEFH, ESOP, and Pharmacist Committee EBMT.

This case study examines an adolescent athlete who had an avulsion fracture of the lesser tuberosity of the humerus. This is a relatively rare injury, although a collection of case studies have identified an increase in this type of injury in the past 15 years. Uniquely, the patient experienced a delay in appropriate diagnosis for approximately 3 years from the time of his initial injury. This is one of the most significant delays in diagnosis and treatment in the current body of literature regarding lesser tuberosity fractures. The authors include a detailed series of imaging studies, including preoperative plain radiographs, preoperative computed tomography, intraoperative arthroscopic images, and postoperative plain radiographs. In addition, a thorough description of the patient's surgery is presented. The degree of scarring to the axillary nerve present in this patient required conversion to a full open reduction. The authors' aim is that this case can be used as a reference for future surgical decision making, particularly in pediatric patients whose injuries are highly chronic or who are actively involved in athletic physical training programs. [ Orthopedics . 2023;46(3):e189-e192.].

Prion diseases are caused by misfolding of either wild-type or mutant forms of the prion protein (PrP) into self-propagating, pathogenic conformers, collectively termed PrPSc. Both wild-type and mutant PrPSc molecules exhibit conformational diversity in vivo, but purified prions generated by the serial protein misfolding cyclic amplification (sPMCA) technique do not display this same diversity in vitro. This discrepancy has left a gap in our understanding of how conformational diversity arises at the molecular level in both types of prions. Here, we use continuous shaking instead of sPMCA to generate conformationally diverse purified prions in vitro. Using this approach, we show for the first time that wild type prions initially seeded by different native strains can propagate as metastable PrPSc conformers with distinguishable strain properties in purified reactions containing a single active cofactor. Propagation of these metastable PrPSc conformers requires appropriate shaking conditions, and changes in these conditions cause all the different PrPSc conformers to converge irreversibly into the same single conformer as that produced in sPMCA reactions. We also use continuous shaking to show that two mutant PrP molecules with different pathogenic point mutations (D177N and E199K) adopt distinguishable PrPSc conformations in reactions containing pure protein substrate without cofactors. Unlike wild-type prions, the conformations of mutant prions appear to be dictated by substrate sequence rather than seed conformation. Overall, our studies using purified substrates in shaking reactions show that wild-type and mutant prions use fundamentally different mechanisms to generate conformational diversity at the molecular level., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Walsh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

The analysis of somatic variation in the mitochondrial genome requires deep sequencing of mitochondrial DNA. This is ordinarily achieved by selective enrichment methods, such as PCR amplification or probe hybridization. These methods can introduce bias and are prone to contamination by nuclear-mitochondrial sequences (NUMTs), elements that can introduce artefacts into heteroplasmy analysis. We isolated intact mitochondria using differential centrifugation and alkaline lysis and subjected purified mitochondrial DNA to a sequence-independent and PCR-free method to obtain ultra-deep (>80,000X) sequencing coverage of the mitochondrial genome. This methodology avoids false-heteroplasmy calls that occur when long-range PCR amplification is used for mitochondrial DNA enrichment. Previously published methods employing mitochondrial DNA purification did not measure mitochondrial DNA enrichment or utilise high coverage short-read sequencing. Here, we describe a protocol that yields mitochondrial DNA and have quantified the increased level of mitochondrial DNA post-enrichment in 7 different mouse tissues. This method will enable researchers to identify changes in low frequency heteroplasmy without introducing PCR biases or NUMT contamination that are incorrectly identified as heteroplasmy when long-range PCR is used., (© 2022. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Methicillin-resistant Staphylococcus aureus (MRSA) is a global healthcare concern. Such resistance has historically been attributed to the acquisition of mecA (or mecC ), which encodes an alternative penicillin binding protein, PBP2a, with low β-lactam affinity. However, recent studies have indicated that penicillin binding protein 4 (PBP4) is also a critical determinant of S. aureus methicillin resistance, particularly among community-acquired MRSA strains. Thus, PBP4 has been considered an intriguing therapeutic target as corresponding inhibitors may restore MRSA β-lactam susceptibility. In addition to its role in antibiotic resistance, PBP4 has also recently been shown to be required for S. aureus cortical bone osteocyte lacuno-canalicular network (OLCN) invasion and colonization, providing the organism with a niche for re-occurring bone infection. From these perspectives, the development of PBP4 inhibitors may have tremendous impact as agents that both reverse methicillin resistance and inhibit the organism's ability to cause chronic osteomyelitis. Accordingly, using a whole-cell high-throughput screen of a 30,000-member small molecule chemical library and secondary assays we identified putative S. aureus PBP4 inhibitors. Quantitative reverse transcriptase mediated PCR and PBP4 binding assays revealed that hits could be further distinguished as compounds that reduce PBP4 expression versus compounds that are likely to affect the protein's function. We also showed that 6.25 µM (2.5 µg/mL) of the lead candidate, 9314848, reverses the organism's PBP4-dependent MRSA phenotype and inhibits its ability to traverse Microfluidic-Silicon Membrane-Canalicular Arrays (µSiM-CA) that model the OLCN orifice. Collectively, these molecules may represent promising potential as PBP4-inhibitors that can be further developed as adjuvants for the treatment of MRSA infections and/or osteomyelitis prophylactics., Competing Interests: J.L.M. is co-founder of SiMPore and holds an equity interest in the company. SiMPore is commercializing the µSiM-CA devices used in this study.

The Comprehensive Geriatric Assessment (CGA) is recommended to guide treatment choices in older patients with cancer. Patients ≥ 70 years referred to our oncology service with a new cancer diagnosis are screened using the G-8. Patients with a score of ≤14 are eligible to attend the Geriatric Oncology and Liaison (GOAL) Clinic in our institution, with referral based on physician discretion. Referred patients undergo multidimensional assessments at baseline. CGA domains assessed include mobility, nutritional, cognitive, and psychological status. Chemotherapy toxicity risk is estimated using the Cancer Aging and Research Group (CARG) calculator. We undertook a retrospective analysis of patients attending the GOAL clinic over a 30-month period to April 2021. The objective was to determine rates of treatment dose modifications, delays, discontinuation, and unscheduled hospitalizations as surrogates for cytotoxic therapy toxicity in these patients. These data were collected retrospectively. Ninety-four patients received chemotherapy; the median age was 76 (70-87) and 45 were female (48%). Seventy-five (80%) had an ECOG PS of 0-1. Seventy-two (77%) had gastrointestinal cancer, and most had stage III (47%) or IV (40%) disease. Chemotherapy with curative intent was received by 51% ( n = 48) and 51% received monotherapy. From the CGA, the median Timed Up and Go was 11 s (7.79-31.6), and 90% reported no falls in the prior 6 months. The median BMI was 26.93 (15.43-39.25), with 70% at risk or frankly malnourished by the Mini Nutritional Assessment. Twenty-seven (29%) patients had impaired cognitive function. Forty-three (46%) had a high risk of toxicity based on the baseline CARG toxicity calculator. Twenty-six (28%) required dose reduction, 55% ( n = 52) required a dose delay, and 36% ( n = 34) had a hospitalization due to toxicity. Thirty-nine patients (42%) discontinued treatment due to toxicity. Despite intensive assessment, clinical optimization and personalized treatment decisions, older adults with cancer remain at high risk of chemotherapy toxicity.

Bottlebrush polymers are a class of semiflexible, hierarchical macromolecules with unique potential for shape-, architecture-, and composition-based structure-property design. It is now well-established that in dilute to semidilute solution, bottlebrush homopolymers adopt a wormlike conformation, which decreases in extension (persistence length) as the concentration and molecular overlap increase. By comparison, the solution phase self-assembly of bottlebrush diblock copolymers (BBCP) in a good solvent remains poorly understood, despite critical relevance for solution processing of ordered phases and photonic crystals. In this work, we combine small-angle X-ray scattering, coarse-grained simulation, and polymer synthesis to map the equilibrium phase behavior and conformation of a set of large, nearly symmetric PS- b -PLA bottlebrush diblock copolymers in toluene. Three BBCP are synthesized, with side chains of number-averaged molecular weights of 4500 (PS) and 4200 g/mol (PLA) and total backbone degrees of polymerization of 100, 255, and 400 repeat units. The grafting density is one side chain per backbone repeat unit. With increasing concentration in solution, all three polymers progress through a similar structural transition: from dispersed, wormlike chains with concentration-dependent (decreasing) extension, through the onset of disordered PS/PLA compositional fluctuations, to the formation of a long-range ordered lamellar phase. With increasing concentration in the microphase-separated regimes, the domain spacing increases as individual chains partially re-extend due to block immiscibility. Increases in the backbone degree of polymerization lead to changes in the scattering profiles which are consistent with the increased segregation strength. Coarse-grained simulations using an implicit side-chain model are performed, and concentration-dependent self-assembly behavior is qualitatively matched to experiments. Finally, using the polymer with the largest backbone length, we demonstrate that lamellar phases develop a well-defined photonic band gap in solution, which can be tuned across the visible spectrum by varying polymer concentration., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Favorable polymer-substrate interactions induce surface orientation fields in block copolymer (BCP) melts. In linear BCP processed near equilibrium, alignment of domains generally persists for a small number of periods (∼4-6 D 0 ) before randomization of domain orientation. Bottlebrush BCP are an emerging class of materials with distinct chain dynamics stemming from substantial molecular rigidity, enabling rapid assembly at ultrahigh (>100 nm) domain periodicities with strong photonic properties (structural color). This work assesses interface-induced ordering in PS- b -PLA bottle b rush diblock copolymer films during thermal annealing between planar surfaces. To clearly observe the decay in orientational order from surface to bulk, we choose to study micron-scale films spanning greater than 200 lamellar periods. In situ optical microscopy and transmission UV-Vis spectroscopy are used to monitor photonic properties during annealing and paired with ex situ UV-Vis reflection measurement, cross-sectional scanning electron microscopy (SEM), and small-angle X-ray scattering (SAXS) to probe the evolution of domain microstructure. Photonic properties were observed to saturate within minutes of annealing at 150 °C, with distinct variation in transmission response as a function of film thickness. The depth of the highly aligned surface region was found to vary stochastically in the range of 30-100 lamellar periods, with the sharpness of the orientation gradient decreasing substantially with increasing film thickness. This observation suggests a competition between growth of aligned, heterogeneously nucleated, grains at the surface and orientationally isotropic, homogeneously nucleated, grains throughout the bulk. This work demonstrates the high potential of bottlebrush block copolymers in rapid fabrication workflows and provides a point of comparison for future application of directed self-assembly to BBCP ordering.

Over the past 5 years, systematic investigation of the mesenteric organ has expanded and shown that the mesentery is the organ in and on which all abdominal digestive organs develop and remain connected to. In turn, this observation has clarified the anatomical foundation of the abdomen and the fundamental order at that level. Findings related to the shape and development of the mesentery have illuminated its function, advancing our understanding of the pathobiology, diagnosis, and treatment of several abdominal and systemic diseases. Inclusion of the mesentery in surgical resections alters the course of benign and malignant diseases. Mesenteric-based scoring systems can enhance the radiological interpretation of abdominal disease. Emerging findings reconcile observations across scientific and clinical fields and have been assimilated into reference curricula and practice guidelines. This Review summarises the developmental, anatomical, and clinical advances made since the mesentery was redesignated as an organ in 2016., Competing Interests: Declaration of interests All authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: In humans, vitamin B-12 (cobalamin) transport involves 3 paralogous proteins: transcobalamin, haptocorrin, and intrinsic factor. Zebrafish (Danio rerio) express 3 genes that encode proteins homologous to known B-12 carrier proteins: tcn2 (a transcobalamin ortholog) and 2 atypical β-domain-only homologs, tcnba and tcnbb., Objectives: Given the orthologous relation between zebrafish Tcn2 and human transcobalamin, we hypothesized that zebrafish carrying null mutations of tcn2 would exhibit phenotypes consistent with vitamin B-12 deficiency., Methods: First-generation and second-generation tcn2-/- zebrafish were characterized using phenotypic assessments, metabolic analyses, viability studies, and transcriptomics., Results: Homozygous tcn2-/- fish produced from a heterozygous cross are viable and fertile but exhibit reduced growth, which persists into adulthood. When first-generation female tcn2-/- fish are bred, their offspring exhibit gross developmental and metabolic defects. These phenotypes are observed in all offspring from a tcn2-/- female regardless of the genotype of the male mating partner, suggesting a maternal effect, and can be rescued with vitamin B-12 supplementation. Transcriptome analyses indicate that offspring from a tcn2-/- female exhibit expression profiles distinct from those of offspring from a tcn2+/+ female, which demonstrate dysregulation of visual perception, fatty acid metabolism, and neurotransmitter signaling pathways., Conclusions: Our findings suggest that the deposition of vitamin B-12 in the yolk by tcn2-/- females may be insufficient to support the early development of their offspring. These data present a compelling model to study the effects of vitamin B-12 deficiency on early development, with a particular emphasis on transgenerational effects and gene-environment interactions., (Published by Oxford University Press on behalf of the American Society for Nutrition 2021.)

The synthesis and biological activity of several novel nitrothiazole, nitrobenzothiazole, and nitrofuran containing antimicrobial agents for the eradication of biofilm-forming Gram-negative and Gram-positive pathogens is described. Nitazoxanide (NTZ), nitrofurantoin, and furazolidone are commercial antimicrobials which were used as models to show how structural modification improved activity toward planktonic bacteria via minimum inhibitory concentration (MIC) assays and biofilms via minimum biofilm eradication concentration (MBEC) assays. Structure-activity relationship (SAR) studies illustrate the ways in which improvements have been made to the aforementioned antimicrobial agents. It is of particular interest in this regard that the introduction of a chloro substituent at the 5-position of NTZ (analog 1b ) resulted in marked activity enhancement, as did the replacement of the 2-acetoxy substituent in the latter compound with a basic amine group (analog 7b ). It is also of importance that analog 4a , which is a simple methacrylamide, displayed noteworthy activity against S. epidermidis biofilms. These lead compounds identified to have high activity towards biofilms provide promise as starting points in future pro-drug studies.

Prodrugs are pharmacologically attenuated derivatives of drugs that undergo bioconversion into the active compound once reaching the targeted site, thereby maximizing their efficiency. This strategy has been implemented in pharmaceuticals to overcome obstacles related to absorption, distribution, and metabolism, as well as with intracellular dyes to ensure concentration within cells. In this study, we provide the first examples of a prodrug strategy that can be applied to simple phenolic antimicrobials to increase their potency against mature biofilms. The addition of (acetoxy)methyl iminodiacetate groups increases the otherwise modest potency of simple phenols. Biofilm-forming bacteria exhibit a heightened tolerance toward antimicrobial agents, thereby accentuating the need for new antibiotics as well as those, which incorporate novel delivery strategies to enhance activity toward biofilms., (© 2020 The Authors. Chemical Biology & Drug Design published by John Wiley & Sons A/S.)

Prions are unorthodox pathogens that cause fatal neurodegenerative diseases in humans and other mammals. Prion propagation occurs through the self-templating of the pathogenic conformer PrPSc, onto the cell-expressed conformer, PrPC. Here we study the conversion of PrPC to PrPSc using a recombinant mouse PrPSc conformer (mouse protein-only recPrPSc) as a unique tool that can convert bank vole but not mouse PrPC substrates in vitro. Thus, its templating ability is not dependent on sequence homology with the substrate. In the present study, we used chimeric bank vole/mouse PrPC substrates to systematically determine the domain that allows for conversion by Mo protein-only recPrPSc. Our results show that that either the presence of the bank vole amino acid residues E227 and S230 or the absence of the second N-linked glycan are sufficient to allow PrPC substrates to be converted by Mo protein-only recPrPSc and several native infectious prion strains. We propose that residues 227 and 230 and the second glycan are part of a C-terminal domain that acts as a linchpin for bank vole and mouse prion conversion., Competing Interests: The authors have declared that no competing interests exist.

The properties of a polymer are known to be intrinsically related to its molecular weight distribution (MWD); however, previous methodologies of MWD control do not use a design and result in arbitrary shaped MWDs. Here we report a precise design to synthesis protocol for producing a targeted MWD design with a simple to use, and chemistry agnostic computer-controlled tubular flow reactor. To support the development of this protocol, we constructed general reactor design rules by combining fluid mechanical principles, polymerization kinetics, and experiments. The ring opening polymerization of lactide, the anionic polymerization of styrene, and the ring opening metathesis polymerization are used as model polymerizations to develop the reactor design rules and synthesize MWD profiles. The derivation of a mathematical model enables the quantitative prediction of the experimental results, and this model provides a tool to explore the limits of any MWD design protocol.

Additive manufacturing of functional materials is limited by control of microstructure and assembly at the nanoscale. In this work, we integrate nonequilibrium self-assembly with direct-write three-dimensional (3D) printing to prepare bottlebrush block copolymer (BBCP) photonic crystals (PCs) with tunable structure color. After varying deposition conditions during printing of a single ink solution, peak reflected wavelength for BBCP PCs span a range of 403 to 626 nm (blue to red), corresponding to an estimated change in d-spacing of >70 nm (Bragg- Snell equation). Physical characterization confirms that these vivid optical effects are underpinned by tuning of lamellar domain spacing, which we attribute to modulation of polymer conformation. Using in situ optical microscopy and solvent-vapor annealing, we identify kinetic trapping of metastable microstructures during printing as the mechanism for domain size control. More generally, we present a robust processing scheme with potential for on-the-fly property tuning of a variety of functional materials., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

Prion diseases are caused by the misfolding of a host-encoded glycoprotein, PrPC, into a pathogenic conformer, PrPSc. Infectious prions can exist as different strains, composed of unique conformations of PrPSc that generate strain-specific biological traits, including distinctive patterns of PrPSc accumulation throughout the brain. Prion strains from different animal species display different cofactor and PrPC glycoform preferences to propagate efficiently in vitro, but it is unknown whether these molecular preferences are specified by the amino acid sequence of PrPC substrate or by the conformation of PrPSc seed. To distinguish between these two possibilities, we used bank vole PrPC to propagate both hamster or mouse prions (which have distinct cofactor and glycosylation preferences) with a single, common substrate. We performed reconstituted sPMCA reactions using either (1) phospholipid or RNA cofactor molecules, or (2) di- or un-glycosylated bank vole PrPC substrate. We found that prion strains from either species are capable of propagating efficiently using bank vole PrPC substrates when reactions contained the same PrPC glycoform or cofactor molecule preferred by the PrPSc seed in its host species. Thus, we conclude that it is the conformation of the input PrPSc seed, not the amino acid sequence of the PrPC substrate, that primarily determines species-specific cofactor and glycosylation preferences. These results support the hypothesis that strain-specific patterns of prion neurotropism are generated by selection of differentially distributed cofactors molecules and/or PrPC glycoforms during prion replication., Competing Interests: The authors have declared that no competing interests exist.

The recalcitrance exhibited by microbial biofilms to conventional disinfectants has motivated the development of new chemical strategies to control and eradicate biofilms. The activities of several small phenolic compounds and their trichloromethylsulfenyl ester derivatives were evaluated against planktonic cells and mature biofilms of Staphylococcus epidermidis and Pseudomonas aeruginosa . Some of the phenolic parent compounds are well-studied constituents of plant essential oils, for example, eugenol, menthol, carvacrol, and thymol. The potency of sulfenate ester derivatives was markedly and consistently increased toward both planktonic cells and biofilms. The mean fold difference between the parent and derivative minimum inhibitory concentration against planktonic cells was 44 for S. epidermidis and 16 for P. aeruginosa . The mean fold difference between the parent and derivative biofilm eradication concentration for 22 tested compounds against both S. epidermidis and P. aeruginosa was 3. This work demonstrates the possibilities of a new class of biofilm-targeting disinfectants deploying a sulfenate ester functional group to increase the antimicrobial potency toward microorganisms in biofilms., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

The mechanism of ring-opening metathesis polymerization (ROMP) for a set of functionalized norbornenyl monomers initiated by a Grubbs third generation precatalyst [(H 2 IMes)(pyr) 2 (Cl) 2 Ru═CHPh] was investigated. Through a series of 12 C/ 13 C and 1 H/ 2 H kinetic isotope effect studies, the rate-determining step for the polymerization was determined to be the formation of the metallacyclobutane ring. This experimental result was further validated through DFT calculations showing that the highest energy transition state is metallacyclobutane formation. The effect of monomer stereochemistry (exo vs endo) of two types of ester substituted monomers was also investigated. Kinetic and spectroscopic evidence supporting the formation of a six-membered chelate through coordination of the proximal polymer ester to the Ru center is presented. This chelation and its impact on the rate of polymerization are shown to vary based on the monomer employed and its stereochemistry. The combination of this knowledge led to the derivation of a generic rate law describing the rate of polymerization of norbornene monomers initiated by a Grubbs third generation catalyst.

Biofilm-forming bacteria present formidable challenges across diverse settings, and there is a need for new antimicrobial agents that are both environmentally acceptable and relatively potent against microorganisms in the biofilm state. The antimicrobial activity of three naturally occurring, low molecular weight, phenols, and their derivatives were evaluated against planktonic and biofilm Staphylococcus epidermidis and Pseudomonas aeruginosa . The structure activity relationships of eugenol, thymol, carvacrol, and their corresponding 2- and 4-allyl, 2-methallyl, and 2- and 4- n -propyl derivatives were evaluated. Allyl derivatives showed a consistent increased potency with both killing and inhibiting planktonic cells but they exhibited a decrease in potency against biofilms. This result underscores the importance of using biofilm assays to develop structure-activity relationships when the end target is biofilm., (Copyright © 2019 Walsh, Livinghouse, Goeres, Mettler and Stewart.)

Background: A complete reproductive immunophenotype is poorly described, with most focus on peripheral blood natural killer cells rather than uterine populations. There is debate regarding normal endometrial levels, with no consensus, and much controversy on correlation with implantation/miscarriage., Aims: Development and validation of a rapid endometrial assessment flow cytometry (FCM) technique, allowing determination of local lymphocyte subset ranges, comparison to peripheral blood, and patient subgroup analysis., Methods: Prospective pilot, assessing patients with prior implantation, failure offered endometrial biopsy before subsequent ART cycle, functioning as therapeutic scratch. HRT regime administered to standardise environment, and progesterone-primed mid-luteal biopsy (five completed days progestogen, P+5) analysed using comprehensive flow panel to identify lymphocyte subsets., Results: Two hundred patients were recruited in a tertiary university-affiliated ART centre. FCM identified differing lymphocyte ranges between peripheral blood and biopsy. Uterine/decidual natural killer cells are the dominant endometrial subtype. Patients with repeated implantation failure had higher uNK levels (52.4 vs 43.7%, p = 0.01). Conversely, B lymphocytes (0.87 vs 0.72%, p = 0.032), pNK (1.21 vs 0.8%, p = 0.041), and NK-T (2.68 vs 2.26, p = 0.031) cells were higher in recurrent pregnancy loss., Conclusion: FCM is widely used to assess cellular populations, but not typically employed for endometrial evaluation. FCM provides a rapid, detailed, and quantitative analysis and reduces inter-observer subjectivity bias. Detailed understanding of the normal endometrial immunophenotype, and associated deviations, may provide insight into the aetiology of infertile patients labelled "unexplained". Failure despite transfer of high grade, or proven euploid blastocysts, is a difficult problem, and endometrial profiling may help identify research areas to determine potential future therapeutic interventions for this difficult to treat population.

Bottlebrush polymers are a class of macromolecules that have recently found use in a wide variety of materials, ranging from lubricating brushes and nanostructured coatings to elastomeric gels that exhibit structural colors. These polymers are characterized by dense branches extending from a central backbone and thus have properties distinct from linear polymers. It remains a challenge to specifically understand conformational properties of these molecules, due to the wide range of architectural parameters that can be present in a system, and thus there is a need to accurately characterize and model these molecules. In this paper, we use a combination of viscometry, light scattering, and computer simulations to gain insight into the conformational properties of dilute solution bottlebrush polymers. We focus on a series of model bottlebrushes consisting of a poly(norbornene) (PNB) backbone with poly(lactic acid) (PLA) side chains. We demonstrate that intrinsic viscosity and hydrodynamic radius are experimental observations sensitive to molecular architecture, exhibiting distinct differences with different choices of branches and backbone lengths. Informed by the atomistic structure of this PNB-PLA system, we rationalize a coarse-grained simulation model that we evaluate using a combination of Brownian dynamics and Monte Carlo simulations. We show that this exhibits quantitative matching to experimental results, enabling us to characterize the overall shape of the bottlebrush via a number of metrics that can be extended to more general bottlebrush architectures.

The protein-only hypothesis predicts that infectious mammalian prions are composed solely of PrPSc, a misfolded conformer of the normal prion protein, PrPC. However, protein-only PrPSc preparations lack significant levels of prion infectivity, leading to the alternative hypothesis that cofactor molecules are required to form infectious prions. Here, we show that prions with parental strain properties and full specific infectivity can be restored from protein-only PrPSc in vitro. The restoration reaction is rapid, potent, and requires bank vole PrPC substrate, post-translational modifications, and cofactor molecules. To our knowledge, this represents the first report in which the essential properties of an infectious mammalian prion have been restored from pure PrP without adaptation. These findings provide evidence for a unified hypothesis of prion infectivity in which the global structure of protein-only PrPSc accurately stores latent infectious and strain information, but cofactor molecules control a reversible switch that unmasks biological infectivity., Competing Interests: The authors have declared that no competing interests exist.

Shape, size, and composition are the most fundamental design features, enabling highly complex functionalities. Despite recent advances, the independent control of shape, size, and chemistry of macromolecules remains a synthetic challenge. We report a scalable methodology to produce large, well-defined macromolecules with programmable shape, size, and chemistry that combines reactor engineering principles and controlled polymerizations. Specifically, bottlebrush polymers with conical, ellipsoidal, and concave architectures are synthesized using two orthogonal polymerizations. The chemical versatility is highlighted by the synthesis of a compositional asymmetric cone. The strong agreement between predictions and experiments validates the precision that this methodology offers., Competing Interests: Conflict of interest statement: An invention disclosure related to this work has been filed: D.G. and D.J.W. filed a US Patent Application, January 2018.

Herein, we report a methodology for the synthesis of polyolefin containing block-copolymers using a catalytic postpolymerization modification strategy. The most common polyolefin grades are converted into macroinitiators using a cross-metathesis reaction. These functionalized polyolefins are then used to initiate living: coordinative ring opening polymerization of lactide, anionic ring opening polymerization of epoxide, and radical polymerization of styrene to yield the corresponding block copolymers. The high activity of the catalysts employed in the different steps offers improved practicality for scalable synthesis.