General-relativistic precession in a black-hole binary.

The general-relativistic phenomenon of spin-induced orbital precession has not yet been observed in strong-field gravity. Gravitational-wave observations of binary black holes (BBHs) are prime candidates, as we expect the astrophysical binary population to contain precessing binaries1,2. Imprints of precession have been investigated in several signals3-5, but no definitive identification of orbital precession has been reported in any of the 84 BBH observations so far5-7 by the Advanced LIGO and Virgo detectors8,9. Here we report the measurement of strong-field precession in the LIGO-Virgo-Kagra gravitational-wave signal GW200129. The binary's orbit precesses at a rate ten orders of magnitude faster than previous weak-field measurements from binary pulsars10-13. We also find that the primary black hole is probably highly spinning. According to current binary population estimates, a GW200129-like signal is extremely unlikely, and therefore presents a direct challenge to many current binary-formation models.

Assessment of endocytic traffic and Ocrl function in the developing zebrafish neuroepithelium.

Endocytosis allows cells to internalise a wide range of molecules from their environment and to maintain their plasma membrane composition. It is vital during development and for maintenance of tissue homeostasis. The ability to visualise endocytosis in vivo requires suitable assays to monitor the process. Here, we describe imaging-based assays to visualise endocytosis in the neuroepithelium of living zebrafish embryos. Injection of fluorescent tracers into the brain ventricles followed by live imaging was used to study fluid-phase or receptor-mediated endocytosis, for which we used receptor-associated protein (RAP, encoded by Lrpap1) as a ligand for low-density lipoprotein receptor-related protein (LRP) receptors. Using dual-colour imaging combined with expression of endocytic markers, it is possible to track the progression of endocytosed tracers and to monitor trafficking dynamics. Using these assays, we reveal a role for the Lowe syndrome protein Ocrl in endocytic trafficking within the neuroepithelium. We also found that the RAP-binding receptor Lrp2 (encoded by lrp2a) appears to contribute only partially to neuroepithelial RAP endocytosis. Altogether, our results provide a basis to track endocytosis within the neuroepithelium in vivo and support a role for Ocrl in this process. This article has an associated First Person interview with the first author of the paper.

Spontaneous thrombosis of high flow pediatric arteriovenous fistulae: Case series of two patients and a comprehensive literature review.

Pediatric pial arteriovenous shunts in the brain and spine are challenging to understand because of low incidence, variable presentation, and associations with genetic syndromes. What is known about their natural history comes from reviews of small series. To better understand the natural history and role for intervention, two cases are presented followed by a review of the literature. In the first case, an infant with a prior history of intracranial hemorrhage from a ruptured pial fistula returns for elective embolization for a second pial fistula which was found to be spontaneously thrombosed 2 weeks later. In the second case, a 5-year-old with a vertebro-vertebral fistula, identified on work up for a heart murmur and documented with diagnostic angiography, is brought for elective embolization 6 weeks later where spontaneous thrombosis is identified. In reviewing the literature on pediatric single-hole fistulae of the brain and spine, the authors offer some morphologic considerations for identifying which high-flow fistulae may undergo spontaneous thrombosis to decrease the potentially unnecessary risk associated with interventions in small children.

Risk Factors for Recent HIV Infections among Adults in 14 Countries in Africa Identified by Population-Based HIV Impact Assessment Surveys, 2015-2019.

Identifying persons who have newly acquired HIV infections is critical for characterizing the HIV epidemic direction. We analyzed pooled data from nationally representative Population-Based HIV Impact Assessment surveys conducted across 14 countries in Africa for recent infection risk factors. We included adults 15-49 years of age who had sex during the previous year and used a recent infection testing algorithm to distinguish recent from long-term infections. We collected risk factor information via participant interviews and assessed correlates of recent infection using multinomial logistic regression, incorporating each survey's complex sampling design. Compared with HIV-negative persons, persons with higher odds of recent HIV infection were women, were divorced/separated/widowed, had multiple recent sex partners, had a recent HIV-positive sex partner or one with unknown status, and lived in communities with higher HIV viremia prevalence. Prevention programs focusing on persons at higher risk for HIV and their sexual partners will contribute to reducing HIV incidence.

Global warming and arctic terns: Estimating climate change impacts on the world's longest migration.

Climate change is one of the top three global threats to seabirds, particularly species that visit polar regions. Arctic terns migrate between both polar regions annually and rely on productive marine areas to forage, on sea ice for rest and foraging, and prevailing winds during flight. Here, we report 21st-century trends in environmental variables affecting arctic terns at key locations along their Atlantic/Indian Ocean migratory flyway during the non-breeding seasons, identified through tracking data. End-of-century climate change projections were derived from Earth System Models and multi-model means calculated in two Shared Socioeconomic Pathways: 'middle-of-the-road' and 'fossil-fuelled development' scenarios. Declines in North Atlantic primary production emerge as a major impact to arctic terns likely to affect their foraging during the 21st century under a 'fossil-fuelled development' scenario. Minimal changes are, however, projected at three other key regions visited by arctic terns (Benguela Upwelling, Subantarctic Indian Ocean and the Southern Ocean). Southern Ocean sea ice extent is likely to decline, but the magnitude of change and potential impacts on tern survival are uncertain. Small changes (<1 m s-1 ) in winds are projected in both scenarios, but with minimal likely impacts on migration routes and duration. However, Southern Ocean westerlies are likely to strengthen and contract closer to the continent, which may require arctic terns to shift routes or flight strategies. Overall, we find minor effects of climate change on the migration of arctic terns, with the exception of poorer foraging in the North Atlantic. However, given that arctic terns travel over huge spatial scales and live for decades, they integrate minor changes in conditions along their migration routes such that the sum effect may be greater than the parts. Meeting carbon emission targets is vital to slow these end-of-century climatic changes and minimise extinction risk for a suite of polar species.

Collapse after Carpal Bone Tunneling. An Underreported Complication?

PURPOSE: To report the complication of carpal bone tunnel collapse in scapholunate reconstruction. METHODS: The authors present six cases of carpal collapse or bone necrosis after bone tunneling for ligamentous reconstruction, three in the scaphoid bone and three in the lunate. RESULTS: All six cases were secondary to ligament reconstruction for chronic scapholunate dissociations, none of which had preoperative structural scaphoid or lunate deformities. CONCLUSIONS: Although the incidence of this occurrence is unknown, the consequences could be substantial; therefore, patients should be warned of this possibility when discussing complications of ligament reconstruction for chronic scapholunate instability requiring the creation of a bone tunnel. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Validity and Reliability of the activPAL4TM for Measurement of Body Postures and Stepping Activity in 6-12-Year-Old Children.

A link between inappropriate physical behaviour patterns (low physical activity and high sedentary behaviour) and poor health outcomes has been observed. To provide evidence to quantify this link, it is important to have valid and reliable assessment tools. This study aimed to assess the validity and reliability of the activPAL4TM monitor for distinguishing postures and measuring stepping activity of 6-12-year-old children. Thirteen children (8.5 ± 1.8 years) engaged in pre-determined standardised (12 min) and non-standardised (6 min) activities. Agreement, specificity and positive predictive value were assessed between the activPAL4TM and direct observation (DO) (nearest 0.1 s). Between-activPAL4TM (inter-device) and between-observer (inter-rater) reliability were determined. Detection of sitting and stepping time and forward purposeful step count were all within 5% of DO. Standing time was slightly overestimated (+10%) and fast walking/jogging steps underestimated (-20%). For non-standardised activities, activPAL4TM step count matched most closely to combined backward and forward purposeful steps; however, agreement varied widely. The activPAL4TM demonstrated high levels of reliability (ICC(1, 1) > 0.976), which were higher in some instances than could be achieved through direct observation (ICC(2, 1) > 0.851 for non-standardised activities). Overall, the activPAL4TM recorded standardised activities well. However, further work is required to establish the exact nature of steps counted by the activPAL4TM.

Agreement of Two Physical Behaviour Monitors for Characterising Posture and Stepping in Children Aged 6-12 Years.

All new physical behaviour measurement devices should be assessed for compatibility with previous devices. Agreement was assessed between the activPAL4TM and activPAL3TM physical behavior monitors within a laboratory and a multi-day free-living context. Healthy children aged 6-12 years performed standardised (sitting, standing, stepping) (12 min) and non-standardised (6 min) activities in a laboratory and a multi-day (median 3 days) free-living assessment whilst wearing both monitors. Agreement was assessed using Bland-Altman plots, sensitivity, and the positive predictive value (PPV). There were 15 children (7M/8F, 8.4 ± 1.8 years old) recruited. For the laboratory-based standardised activities, sitting time, stepping time, and fast walking/jogging step count were all within ±5% agreement. However, the activPAL4TM standing time was lower (-6.4%) and normal speed walking step count higher (+7.8%) than those of the activPAL3TM. For non-standardised activities, a higher step count was recorded by the activPAL4TM (+4.9%). The standardised activity sensitivity and PPV were all >90%, but the non-standardised activity values were lower. For free-living agreement, the standing time was lower (-7.6%) and step count higher (all steps + 2.2%, steps with cadence >100 step/min + 6.6%) for the activPAL4TM than the activPAL3TM. This study highlights differences in outcomes as determined by the activPAL4TM and activPAL3TM, which should be considered when comparing outcomes between studies.

Multidimensional Evaluation of Screening Brief Intervention and Referral to Treatment Training for Medical Students.

OBJECTIVE: Screening, Brief Intervention, and Referral to Treatment (SBIRT) is an evidence-based approach to identifying and addressing alcohol use in non-specialty settings. Many medical schools teach SBIRT, but most published evaluations of these efforts exclude rigorous skill assessments and teaching methods. METHODS: During the 2017-2018 academic year, 146 third-year medical students received classroom-based learning on SBIRT and motivational interviewing (MI) and at least two SBIRT practices with feedback as part of a 4-week psychiatry clerkship. The objective of this curriculum was to improve SBIRT knowledge, attitudes, and confidence and enable learners to skillfully deliver SBIRT. Outcomes evaluated included satisfaction, knowledge, attitudes and confidence, and clinical skill in delivering SBIRT to a standardized patient (rated by the actor, as well as an expert). RESULTS: Results indicated acceptable satisfaction at post-curriculum and significant improvements in attitudes and knowledge from pre- to post-curriculum. On the clinical skills exam, all students were rated as having mastered at least 80% of SBIRT elements by standardized patients and 91.8% were rated at this level by a faculty expert. Student attitudes and knowledge were unrelated to expert ratings, and standardized patient ratings had limited associations with expert ratings. CONCLUSIONS: These results suggest curriculum objectives were achieved and provide unique contributions to the SBIRT curricular outcome research for healthcare trainees. Other findings included that trainee knowledge and confidence may not relate to skill, and standardized patient feedback provides different information on SBIRT and MI skill than expert ratings.

Use of Epidemiology Surge Support to Enhance Robustness and Expand Capacity of SARS-CoV-2 Pandemic Response, South Africa.

As COVID-19 cases increased during the first weeks of the pandemic in South Africa, the National Institute of Communicable Diseases requested assistance with epidemiologic and surveillance expertise from the US Centers for Disease Control and Prevention South Africa. By leveraging its existing relationship with the National Institute of Communicable Diseases for >2 months, the US Centers for Disease Control and Prevention South Africa supported data capture and file organization, data quality reviews, data analytics, laboratory strengthening, and the development and review of COVID-19 guidance This case study provides an account of the resources and the technical, logistical, and organizational capacity leveraged to support a rapid response to the COVID-19 pandemic in South Africa.

High avidity drives the interaction between the streptococcal C1 phage endolysin, PlyC, with the cell surface carbohydrates of Group A Streptococcus.

Endolysin enzymes from bacteriophage cause bacterial lysis by degrading the peptidoglycan cell wall. The streptococcal C1 phage endolysin PlyC, is the most potent endolysin described to date and can rapidly lyse group A, C, and E streptococci. PlyC is known to bind the Group A streptococcal cell wall, but the specific molecular target or the binding site within PlyC remain uncharacterized. Here we report for the first time, that the polyrhamnose backbone of the Group A streptococcal cell wall is the binding target of PlyC. We have also characterized the putative rhamnose binding groove of PlyC and found four key residues that were critical to either the folding or the cell wall binding action of PlyC. Based on our results, we suggest that the interaction between PlyC and the cell wall may not be a high-affinity interaction as previously proposed, but rather a high avidity one, allowing for PlyC's remarkable lytic activity. Resistance to our current antibiotics is reaching crisis levels and there is an urgent need to develop the antibacterial agents with new modes of action. A detailed understanding of this potent endolysin may facilitate future developments of PlyC as a tool against the rise of antibiotic resistance.

The LHC Olympics 2020 a community challenge for anomaly detection in high energy physics.

A new paradigm for data-driven, model-agnostic new physics searches at colliders is emerging, and aims to leverage recent breakthroughs in anomaly detection and machine learning. In order to develop and benchmark new anomaly detection methods within this framework, it is essential to have standard datasets. To this end, we have created the LHC Olympics 2020, a community challenge accompanied by a set of simulated collider events. Participants in these Olympics have developed their methods using an R&D dataset and then tested them on black boxes: datasets with an unknown anomaly (or not). Methods made use of modern machine learning tools and were based on unsupervised learning (autoencoders, generative adversarial networks, normalizing flows), weakly supervised learning, and semi-supervised learning. This paper will review the LHC Olympics 2020 challenge, including an overview of the competition, a description of methods deployed in the competition, lessons learned from the experience, and implications for data analyses with future datasets as well as future colliders.

Eight Metagenome-Assembled Genomes Provide Evidence for Microbial Adaptation in 20,000- to 1,000,000-Year-Old Siberian Permafrost.

Permafrost microbes may be metabolically active in microscopic layers of liquid brines, even in ancient soil. Metagenomics can help discern whether permafrost microbes show adaptations to this environment. Thirty-three metagenome-assembled genomes (MAGs) were obtained from six depths (3.5 m to 20 m) of freshly cored permafrost from the Siberian Kolyma-Indigirka Lowland region. These soils have been continuously frozen for ∼20,000 to 1,000,000 years. Eight of these MAGs were ≥80% complete with <10% contamination and were taxonomically identified as Aminicenantes, Atribacteria, Chloroflexi, and Actinobacteria within bacteria and Thermoprofundales within archaea. MAGs from these taxa have been obtained previously from nonpermafrost environments and have been suggested to show adaptations to long-term energy starvation, but they have never been explored in ancient permafrost. The permafrost MAGs had greater proportions in the Clusters of Orthologous Groups (COGs) categories of energy production and conversion and carbohydrate transport and metabolism than did their nonpermafrost counterparts. They also contained genes for trehalose synthesis, thymine metabolism, mevalonate biosynthesis, and cellulose degradation, which were less prevalent in nonpermafrost genomes. Many of these genes are involved in membrane stabilization and osmotic stress responses, consistent with adaptation to the anoxic, high-ionic-strength, cold environments of permafrost brine films. Our results suggest that this ancient permafrost contains DNA of high enough quality to assemble MAGs from microorganisms with adaptations to survive long-term freezing in this extreme environment. IMPORTANCE Permafrost around the world is thawing rapidly. Many scientists from a variety of disciplines have shown the importance of understanding what will happen to our ecosystem, commerce, and climate when permafrost thaws. The fate of permafrost microorganisms is connected to these predicted rapid environmental changes. Studying ancient permafrost with culture-independent techniques can give a glimpse into how these microorganisms function under these extreme low-temperature and low-energy conditions. This will facilitate understanding how they will change with the environment. This study presents genomic data from this unique environment ∼20,000 to 1,000,000 years of age.

Assessing Health Care Utilization and Compliance in Kawasaki Disease.

OBJECTIVE: To characterize health care utilization and costs associated with care after diagnosis of Kawasaki disease including adherence to guidelines for echocardiograms. STUDY DESIGN: We analyzed children hospitalized for Kawasaki disease using 2015-2017 national Truven MarketScan commercial claims data. The mean 90-day prehospitalization utilization and costs were quantified and compared with the 90 days posthospitalization via Wilcoxon 2-sample test. Adherence to echocardiogram guidelines was examined using multivariable logistic regression to identify factors associated with adherence. RESULTS: The mean total payments 90 days prior to hospitalization ($2090; n = 360) were significantly lower than those after discharge ($3778), though out of pocket costs were higher ($400 vs $270) (P < .0001). There was an increase in office visits, medical procedures, and echocardiograms after discharge. A majority of health care utilization before hospitalization occurred in the 7 days immediately prior to the date of admission; 51% obtained an echocardiogram within the first 2 weeks, and 14% were completely adherent with recommendations. Children with greater utilization prior to admission were more likely to adhere to American Heart Association guidelines for follow-up echocardiograms (OR 1.03, 95% CI 1.01-1.06). CONCLUSIONS: Outpatient health care expenditure nearly doubles after Kawasaki disease hospital discharge when compared with prehospitalization, suggesting the financial ramifications of this diagnosis persist beyond costs incurred during hospitalization. A significant portion of patients do not receive guideline recommended follow-up echocardiograms. This issue should be explored in more detail given the morbidity and mortality associated with this diagnosis.

Overcoming Barriers to HIV Care: Findings from a Peer-Delivered, Community-Based, Linkage Case Management Program (CommLink), Eswatini, 2015-2018.

To help persons living with HIV (PLHIV) in Eswatini initiate antiretroviral therapy (ART), the CommLink case-management program provided a comprehensive package of linkage services delivered by HIV-positive, peer counselors. Of 1250 PLHIV participants aged ≥ 15 years diagnosed in community settings, 75% reported one or more barriers to care (e.g., fearing stigmatization). Peer counselors helped resolve 1405 (65%) of 2166 identified barriers. During Test and Treat (October 2016-September 2018), the percentage of participants who initiated ART and returned for ≥ 1 antiretroviral refills was 92% overall (759/824); 99% (155/156) among participants without any identified barriers; 96% (544/564) among participants whose counselors helped resolve all or all but one barrier; and 58% (59/102) among participants who had ≥ 2 unresolved barriers to care. The success of CommLink is attributed, at least in part, to peer counselors who helped their clients avoid or at least temporarily resolve many well-known barriers to HIV care.

RESUMEN: Para ayudar a las personas que viven con el VIH (PVVIH) en Eswatini a iniciar la terapia antirretroviral (TARV), el programa de gestión de casos CommLink proporcionó un paquete integral de servicios de la vinculación prestados por consejeros pares VIH positivos. De los 1.250 participantes de las PVVIH de 15 años o más diagnosticados en entornos comunitarios, el 75% informó una o más barreras para la atención (por ejemplo, por temor a la estigmatización). Los consejeros pares ayudaron a resolver 1.405 (65%) de 2.166 barreras identificadas. Durante el período de prueba y tratamiento (octubre de 2016 - septiembre de 2018), el porcentaje de participantes que iniciaron TARV y recibieron ≥ 1 recargas antirretroviral fue del 92% en general (759/824); 99% (155/156) entre los participantes sin barreras identificadas; 96% (544/564) entre los participantes cuyos consejeros ayudaron a resolver todas o todas las barreras excepto una; y 58% (59/102) entre los participantes que tenían ≥ 2 barreras no resueltas para la atención. El éxito de CommLink se atribuye, al menos en parte, a los consejeros pares que ayudaron a sus clientes a evitar o al menos temporalmente resolver muchas barreras conocidas para la atención del VIH.

Comparative Metagenomics of the Active Layer and Permafrost from Low-Carbon Soil in the Canadian High Arctic.

Approximately 87% of the Arctic consists of low-organic carbon mineral soil, but knowledge of microbial activity in low-carbon permafrost (PF) and active layer soils remains limited. This study investigated the taxonomic composition and genetic potential of microbial communities at contrasting depths of the active layer (5, 35, and 65 cm below surface, bls) and PF (80 cm bls). We showed microbial communities in PF to be taxonomically and functionally different from those in the active layer. 16S rRNA gene sequence analysis revealed higher biodiversity in the active layer than in PF, and biodiversity decreased significantly with depth. The reconstructed 91 metagenome-assembled genomes showed that PF was dominated by heterotrophic, fermenting Bacteroidota using nitrite as their main electron acceptor. Prevalent microbes identified in the active layer belonged to bacterial taxa, gaining energy via aerobic respiration. Gene abundance in metagenomes revealed enrichment of genes encoding the plant-derived polysaccharide degradation and metabolism of nitrate and sulfate in PF, whereas genes encoding methane/ammonia oxidation, cold-shock protein, and two-component systems were generally more abundant in the active layer, particularly at 5 cm bls. The results of this study deepen our understanding of the low-carbon Arctic soil microbiome and improve prediction of the impacts of thawing PF.

The Balance between Open and Robotic Training among Graduating Urology Residents-Does Surgical Technique Need Monitoring?

PURPOSE: A minimum number of index procedures is required for graduation. Without thresholds for surgical technique, it is unclear if robotic and open learning is balanced. We assessed the distribution of robotic and open surgeries performed by residents upon graduation. MATERIALS AND METHODS: Voluntary Accreditation Council for Graduate Medical Education resident case logs from 11 institutions were de-identified and trends in robotic and open major surgeries were compared using Wilcoxon rank sum and 2-sample t-tests. RESULTS: A total of 89,199 major cases were recorded by 209 graduates from 2011 to 2017. The median proportion of robotic cases increased from 2011 to 2017 in reconstruction (4.7% to 15.2%), oncology (27.5% to 54.2%) and pediatrics (0% to 10.9%) (all values p <0.001). Robotic and open cases remained most divergent in reconstruction, with a median of 12 robotic (IQR 9-19) to 70 open cases (IQR 55-106) being performed by residents in 2017. Similar observations occurred in pediatrics. In oncology the number of robotic procedures superseded that of open in 2016 and rose to a median of 148 robotic (IQR 108-214) to 121 open cases (IQR 90-169) in 2017, with the driver being robotic prostatectomy. Substantial differences in surgical technique were observed between institutions and among graduates from the same institution. CONCLUSIONS: Although robotic volume is increasing, the balance of surgical technique and the pace of change differ in reconstruction, oncology and pediatrics, as well as among individual institutions and graduates themselves. This raises questions about whether more specific guidelines are needed to ensure equity and standardization in training.

Lead Particle Size Fractionation and Identification in Newark, New Jersey's Drinking Water.

Following a pH reduction in their drinking water over a span of more than 20 years, the City of Newark, New Jersey, has struggled with elevated lead (Pb) release from Pb service lines and domestic plumbing in the zone fed by the Pequannock Water Treatment Plant. In response, Newark initiated orthophosphate addition and provided faucet-mounted point-of-use (POU) filters and pitcher filters certified for Pb and particulate reduction under NSF/ANSI Standards 53 and 42 to residential homes in that zone. Water chemistry analysis and size fractionation sampling were performed at four of these houses. Analysis of the particulate material retained by the fractionation filters revealed that Pb was dominantly present in the water as fine Pb(II) orthophosphate particles. A considerable amount of the particulates occurred as a nanoscale fraction that sometimes passed through the POU faucet or pitcher filtration units. Scanning electron microscopy, transmission electron microscopy, and energy-dispersive spectroscopy analyses showed that the nanoparticles (<100 nm) and their aggregates were composed of Pb, phosphorus, and chlorine, which are consistent with pyromorphite, Pb5(PO4)3Cl. Electron diffraction and X-ray analyses supported the presence of hydroxypyromorphite and chloropyromorphite nanoparticles and the size range estimates from the imaging. This research confirmed that nonadherent Pb(II)-orthophosphate nanoparticles were an important form of Pb in drinking water in the Pequannock water quality zone of Newark.

Functional penile replantation after traumatic avulsion amputation below the pubis: A case report.

Penile amputation is a rare injury with significant posttraumatic ramifications. We present a case of successful immediate replantation after traumatic penile avulsion in a 52-year-old male patient. The patient reported his penis was caught in machinery during a boating accident, and avulsed at the level of the pubis. Immediate replantation of this proximal avulsion injury with no suitable proximal arterial stumps required transfer of the superficial inferior epigastric artery for arterial inflow. One artery and two veins were repaired. The urethral injury was found to be immediately distal to the urethral sphincter in the membranous portion, and repaired primarily. Urinary diversion was performed with a suprapubic catheter until the repair had healed. The postoperative course was complicated by less than 10% skin necrosis requiring skin grafting. At three years follow up, the patient has a penis with normal urinary function and is able to obtain erections with pharmacologic aids. Avulsion should not preclude penile replantation, which may have acceptable functional and esthetic results.

Chemically Tuning Quantized Acoustic Phonons in 2D Layered MoO3 Nanoribbons.

Molybdenum trioxide (α-MoO3) is a 2D layered metal oxide that can be altered in color from transparent white to dark blue with reversible intercalation of zerovalent metals, and whose mechanical properties can be controlled through intercalation. Here, we use Brillouin laser light spectroscopy to map the entire angular dispersion curves of multiple acoustic phonon branches of 2D layered MoO3, directly probing the effects of phonon quantum confinement when the phonon wavelength is comparable to the material thickness. Since acoustic phonons dictate elasticity, we thereby determine the full elastic stiffness tensor and the thickness of each nanoribbon to a statistical precision (derived from standard error propagation) corresponding to less than a monolayer. We show how intercalation of metallic Sn, Co, and Cu can chemically tune the quantized acoustic phonons and elasticity of MoO3 nanoribbons. This work provides the methodology to extract precise elastic constants from complex Brillouin scattering of 2D materials, taking advantage of phonon confinement to capture the complete elastic response with a single scattering geometry.