Rhythmic chew cycles with distinct fast and slow phases are ancestral to gnathostomes.

Intra-oral food processing, including chewing, is important for safe swallowing and efficient nutrient assimilation across tetrapods. Gape cycles in tetrapod chewing consist of four phases (fast open and -close, and slow open and -close), with processing mainly occurring during slow close. Basal aquatic-feeding vertebrates also process food intraorally, but whether their chew cycles are partitioned into distinct phases, and how rhythmic their chewing is, remains unknown. Here, we show that chew cycles from sharks to salamanders are as rhythmic as those of mammals, and consist of at least three, and often four phases, with phase distinction occasionally lacking during jaw opening. In fishes and aquatic-feeding salamanders, fast open has the most variable duration, more closely resembling mammals than basal amniotes (lepidosaurs). Across ontogenetically or behaviourally mediated terrestrialization, salamanders show a distinct pattern of the second closing phase (near-contact) being faster than the first, with no clear pattern in partitioning of variability across phases. Our results suggest that distinct fast and slow chew cycle phases are ancestral for jawed vertebrates, followed by a complicated evolutionary history of cycle phase durations and jaw velocities across fishes, basal tetrapods and mammals. These results raise new questions about the mechanical and sensorimotor underpinnings of vertebrate food processing. This article is part of the theme issue 'Food processing and nutritional assimilation in animals'.

Long Head of Triceps Tendon Transfer for Agenesis of Biceps and Brachialis: Two Cases.

Congenital lack of elbow flexion results in significant disability and may be seen in conjunction with syndromes, plexopathies, neuromuscular disorders, or as an isolated muscular agenesis of elbow flexors. There are many tendon transfer options to address this issue, but there is a lack of data on the functional results in the pediatric population. In this series, we present 1 patient with isolated muscular agenesis of the biceps and brachialis musculotendinous units and another with this same muscular agenesis in the setting of arthrogryposis. They were treated with anterior ulnar nerve transposition and transfer of the long head of triceps tendon around 2 years of age resulting in functional elbow flexion in both patients.

Predictors of Reinfection in Prosthetic Joint Infections Following Two-Stage Reimplantation.

BACKGROUND: Two-stage reimplantation is an effective treatment for periprosthetic joint infection (PJI). Many factors are involved in the variable success of this procedure. The purpose of this study is to examine the relationship between patient risk factors, comorbidities, and the pathogen on reinfection rates following two-stage reimplantation. METHODS: We evaluated 158 patients treated for PJI from 2008-2019. Only patients who had completed a two-stage exchange were included. Patient demographics, comorbidities, laboratory values, time-to-reimplantation, pathogen, antibiotic sensitivities, host status, and reinfection rates were assessed. Multivariate analysis was performed to identify correlation between risk factors and reinfection. A P-value < .05 was considered statistically significant. RESULTS: 31 patients experienced a reinfection (19.6%). There was a statistically significant association between infection with Methicillin Sensitive Staphylococcus Aureus (MSSA) and reinfection (P = .046). Patients with a reinfection also had a significantly greater median serum C-reactive protein (CRP) level (12.65 g/dL) at the time of diagnosis compared to patients without a reinfection (5.0 g/dL) (P = .010). Median Erythrocyte Sedimentation Rate (ESR) (56 in no re-infection and 69 in re-infection) and time-to-reimplantation (101 days in no reinfection and 141 days in reinfection) demonstrated a trend toward an association with re-infection but were not statistically significant (P = .055 and P = .054 respectively). CONCLUSION: As the number of arthroplasties continue to rise, PJIs are increasing proportionately and represent a significant revision burden. Elevated C-reactive protein (CRP) levels and Methicillin Sensitive Staphylococcus aureus (MSSA) infection were strongly associated with failure of a two-stage reimplantation. While not statistically significant with our numbers, there were strong trends toward an association between elevated Erythrocyte Sedimentation Rate (ESR), longer time-to-reimplantation, and reinfection.

An optical neural network using less than 1 photon per multiplication.

Deep learning has become a widespread tool in both science and industry. However, continued progress is hampered by the rapid growth in energy costs of ever-larger deep neural networks. Optical neural networks provide a potential means to solve the energy-cost problem faced by deep learning. Here, we experimentally demonstrate an optical neural network based on optical dot products that achieves 99% accuracy on handwritten-digit classification using ~3.1 detected photons per weight multiplication and ~90% accuracy using ~0.66 photons (~2.5 × 10-19 J of optical energy) per weight multiplication. The fundamental principle enabling our sub-photon-per-multiplication demonstration-noise reduction from the accumulation of scalar multiplications in dot-product sums-is applicable to many different optical-neural-network architectures. Our work shows that optical neural networks can achieve accurate results using extremely low optical energies.

Precision medicine research with American Indian and Alaska Native communities: Results of a deliberative engagement with tribal leaders.

PURPOSE: Amid calls for greater diversity in precision medicine research, the perspectives of Indigenous people have been underexplored. Our goals were to understand tribal leaders' views regarding the potential benefits and risks of such research, explore its priority for their communities, and identify the policies and safeguards they consider essential. This article reports on the participants' perspectives regarding governance and policy, stewardship and sharing of information and biospecimens, and informed consent. METHODS: After informal local dialogs with 21 tribal leaders, we convened a 2.5-day deliberation with tribal leaders (N = 10) in Anchorage, Alaska, in June 2019 using a combination of small group and plenary discussion, ranking, and voting exercises to explore the perspectives on precision medicine research. RESULTS: Tribal sovereignty was central to participants' ideas about precision medicine research. Although views were generally positive, provided that the appropriate controls were in place, some kinds of research were deemed unacceptable, and the collection of certain biospecimens was rejected by some participants. Differences were observed regarding the acceptability of broad consent. CONCLUSION: Tribal leaders in this study were generally supportive of precision medicine research, with the caveat that tribal oversight is essential for the establishment of research repositories and the conduct of research involving Indigenous participants.

Diffusion of an economic development policy innovation: explaining the international spread of casino gambling.

This study uses an event history analysis to examine the factors that lead to the adoption of casino gambling among 13 nations around the world. Specifically, measures of fiscal stress, economic development, tourism, religiosity, and income levels are tested for their relationship to national decisions to legalize casino gambling. This study found that economic development needs, as measured by general unemployment rates, were associated with the casino legalization decisions of national governments. Higher unemployment rates were more likely in the years that nations legalized casino gambling. Religiosity, measured by frequency of church attendance, was also found to be a significant barrier in legalization decisions. Measures of fiscal stress, tourism, and income levels were not found to have significant relationships with the legalization decisions. This is interesting because these factors are often cited in case studies, media reports, and the statements of politicians during legalization processes. This study points to the need for further research in several areas. Further exploration of potential explanatory variables and more appropriate measures of currently theorized factors is warranted. Another area for further research is the seeming contradictory findings of multiple statistical analyses and multiple anecdotal findings of the impacts of fiscal stress on the casino legalization decision.

Early outcomes after hip arthroscopy for femoroacetabular impingement in the athletic adolescent patient: a preliminary report.

BACKGROUND: Hip arthroscopy is becoming a more popular method of treatment of pediatric hip disorders. We report on the treatment of femoroacetabular impingement (FAI) in the adolescent population. METHODS: Between March 2005 and May 2006, 16 patients (aged 16 years or younger) underwent hip arthroscopy for FAI. There were 14 female adolescents and 2 male adolescents, with 1 patient undergoing a bilateral procedure. Five patients had isolated pincer impingement, 2 had isolated cam impingement, and 9 had mixed pathology. All patients had labral pathology. Seven patients were treated with suture anchor repair of the labrum and 9 with partial labral debridement. Subjective data were collected from each patient during their initial visit and at follow-up after surgery. Subjective data included the modified Harris hip score (MHHS), patient satisfaction, and hip outcome score (HOS) activities of daily living (ADL), and sports subscales. RESULTS: The mean age at the time of arthroscopy was 15 years old (range, 11-16 years). The mean preoperative MHHS was 55 (range, 33-70), HOS ADL was 58 (range, 38-75), and HOS sport was 33 (range, 0-78). The mean time from injury to surgery was 10.6 months (range, 6 weeks-30 months). The mean time to follow-up was 1.36 years (range, 1-2 years). The mean postoperative MHHS improved 35 points to 90 (range, 70-100; P = 0.005), postoperative HOS ADL improved 36 points to 94 (range, 74-100; P = 0.001), and postoperative HOS sport score improved 56 points to 89 (range, 58-100; P = 0.001). The mean patient satisfaction score was 9 (range, 9-10). CONCLUSIONS: Hip arthroscopy for FAI in the adolescent population produces excellent improvement in function and a high level of patient satisfaction in the short-term.

Can microfracture produce repair tissue in acetabular chondral defects?

PURPOSE: The purpose of this study was to investigate percent fill and repair grade of microfractured lesions of the acetabulum. METHODS: Nine patients underwent revision hip arthroscopy for a variety of procedures after undergoing microfracture for treatment of a full-thickness chondral defect of the acetabulum at primary arthroscopy. The size of the chondral defect was measured during primary arthroscopy, and the percent fill of the defect and repair grade were noted at revision hip arthroscopy. RESULTS: Mean time from primary arthroscopy to revision was 20 months (range, 10 to 36 months). The average percent fill of the acetabular chondral lesions at second-look was 91% (range, 25% to 100%). Eight of the patients had grade 1 or 2 repair product at second-look. The 1 patient with 25% fill and grade 4 repair product had diffuse osteoarthritis on the femur and acetabulum at primary microfracture. One patient required total hip arthroplasty 66 months after the index microfracture. CONCLUSIONS: In this study, 8 of 9 patients had 95% to 100% coverage of an isolated acetabular chondral lesion or acetabular lesion associated with a femoral head lesion, with grade 1 or 2 appearance of the repair product at an average of 20 months follow-up. One patient who had diffuse osteoarthritis failed, with only 25% coverage with a grade IV appearance of the repair product 10 months after index arthroscopy. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

The late pollen actins are essential for normal male and female development in Arabidopsis.

In angiosperms the late pollen actins (LPAs) are strongly expressed in mature pollen and pollen tubes and at much lower levels in ovules. Four Arabidopsis lines with homozygous knockout mutations in the four individual LPA genes displayed normal flowers, pollen, and seed set. However, when all four LPAs were silenced simultaneously with a single RNA interference (RNAi) construct targeting the 3'UTR of each mRNA, obvious reproductive defects were observed. Western analysis of various Late Pollen actin RNA interference (LPRi) epialleles showed total LPA protein and RNA expression levels were knocked down from 0% to 95% compared to wild-type levels. Reciprocal crosses with the RNAi lines demonstrated that lowered LPA expression was associated with defects in both male and female fertility. Strong epialleles showed significant reductions in normal silique and seed production and were nearly sterile. Dissection of the siliques from moderate LPRi epialleles revealed many unfertilized ovules, increased numbers of aborted seeds, and decreased numbers of healthy seeds. Microscopic analysis of LPRi pollen indicated that the pollen shape and size were normal, but pollen germinated poorly. While multiple LPA genes may have some functional redundancy, the combined expression of multiple LPA genes appears essential to normal male and female reproductive development.