Adaptive responses in Cambrian predator and prey highlight the arms race during the rise of animals.

Predation is an important driver of species-level change in modern and fossil ecosystems, often through selection for defensive phenotypes in prey responding to predation pressures over time. Records of changes in shell morphology and injury patterns in biomineralized taxa are ideal for demonstrating such adaptive responses. The rapid increase in diversity and abundance of biomineralizing organisms during the early Cambrian is often attributed to predation and an evolutionary arms race.

Type-H endothelial cell protein Clec14a orchestrates osteoblast activity during trabecular bone formation and patterning.

Type-H capillary endothelial cells control bone formation during embryogenesis and postnatal growth but few signalling mechanisms underpinning this influence have been characterised. Here, we identify a highly expressed type-H endothelial cell protein, Clec14a, and explore its role in coordinating osteoblast activity. Expression of Clec14a and its ligand, Mmrn2 are high in murine type-H endothelial cells but absent from osteoblasts.

Surgical approaches of shoulder calcific tendonitis: a systematic review and meta-analysis.

Background: Calcific tendonitis is a painful shoulder disorder characterized by calcium deposits (CDs) in the rotator cuff tendon. This systematic review and meta-analysis examined the most efficient surgical procedure for calcific tendonitis. This includes the comparison between the three main surgical techniques: CD removal, CD removal with subacromial decompression (SAD) and CD removal with tendon repair with respect to functional outcomes and pain control scores.

Late Ordovician eurypterid preserves oldest euchelicerate musculature in pyrite.

Pyritization of soft tissues of invertebrates is rare in the fossil record. In New York State, it occurs in black shales of the Lorraine Group (Late Ordovician), the best-known example of which is Beecher's Trilobite Bed. Exceptional preservation at the quarry where this bed is exposed allowed detailed examination of trilobite and ostracod soft-tissue anatomy.

Evidence for cryptic molting behavior in the trilobite Toxochasmops vormsiensis from the Upper Ordovician Katian Kõrgessaare Formation, Estonia.

Documentation of cryptic trilobite behavior has presented important insights into the paleoecology of this fully extinct arthropod group. One such example is the preservation of trilobites inside the remains of larger animals. To date, evidence for trilobites within cephalopods, gastropods, hyoliths, and other trilobites has been presented.

Malformed trilobites from the Cambrian, Ordovician, and Silurian of Australia.

Biomineralised remains of trilobites provide important insight into the evolutionary history of a diverse, extinct group of arthropods. Their exoskeletons are also ideal for recording malformations, including evidence of post-injury repair. Re-examination of historic collections and the study of new specimens is important for enhancing knowledge on trilobite malformations across this diverse clade.

Five new malformed trilobites from Cambrian and Ordovician deposits from the Natural History Museum.

Injured trilobites present insight into how a completely extinct group of arthropods responded to traumatic experiences, such as failed predation and moulting complications. These specimens are therefore important for more thoroughly understanding the Paleozoic predator-prey systems that involved trilobites. To expand the record of injured trilobites, we present new examples of injured and from the Campsite Cliff Shale Member of the Burgess Shale Formation (Cambrian, Miaolingian, Wuliuan), () from the Jince Formation (Cambrian, Miaolingian, Drumian), from the Llanfawr Mudstones Formation (Middle-Late Ordovician, Darriwilian-Sandbian), and from the Meadowtown Formation, (Middle-Late Ordovician, Darriwilian-Sandbian).

Location of the posterior interosseous nerve in relation to common lateral approaches to the elbow.

Purpose: The risk of posterior interosseous nerve (PIN) injury during surgical approaches to the lateral elbow varies depending on the chosen approach, level of dissection, and rotational position of the forearm. Previous studies evaluated the trajectory of the PIN in specific surgical applications to reduce iatrogenic nerve injuries. The goal of this study is to examine the location of the PIN using common lateral approaches with varying forearm rotation.

The brain-derived neurotrophic factor Val66met polymorphism is associated with better attention and working memory performance and resilience to mild chronic stress.

The val66met polymorphism of the brain-derived neurotrophic factor (BDNF) gene has been identified as a potential moderator for the relationship between chronic stress and executive functioning. However, whether the presence of the met allele increases cognitive vulnerability or resilience to stress has yet to be determined. Given the established effects of autonomic activity and psychological arousal on executive functioning, in the present study, 56 healthy university students completed self-report measures of chronic stress, positive arousal (vigour) and negative arousal (anxiety) and measured heart-rate variability to quantify autonomic activity.

Genetic mapping of the locus in and the evolution of apomixis in the Lactuceae.

var. (syn. ; ) is a versatile model used to study gametophytic apomixis.

Lower trapezius tendon transfer for irreparable rotator cuff injuries: a scoping review.

Background: Rotator cuff tears are a common source of shoulder pain and dysfunction. An irreparable rotator cuff tear poses a particular treatment challenge. There have been few studies reporting the outcomes of lower trapezius tendon (LTT) transfer for irreparable rotator cuff injuries.

Raptorial appendages of the Cambrian apex predator are built for soft prey and speed.

The stem-group euarthropod is one of the largest Cambrian animals and is often considered the quintessential apex predator of its time. This radiodont is commonly interpreted as a demersal hunter, responsible for inflicting injuries seen in benthic trilobites. However, controversy surrounds the ability of to use its spinose frontal appendages to masticate or even manipulate biomineralized prey.

Avoiding the posterior interosseous nerve during 2-incision distal biceps tendon repair: an anatomic study.

Background: The posterior interosseous nerve (PIN) is the most commonly injured motor nerve during distal biceps tendon repair resulting in severe functional deficits. Anatomic studies of distal biceps tendon repairs have evaluated the proximity of the PIN to the anterior radial shaft in supination, but limited studies have evaluated the location of the PIN in relation to the radial tuberosity (RT), and none have examined its relation to the subcutaneous border of the ulna (SBU) with varying forearm rotation. This study evaluates the location of the PIN in relation to the RT and SBU to help guide surgeons in safe placement of the dorsal incision and the safest zones of dissection.

Stress shielding following stemless anatomic total shoulder arthroplasty.

Background: Finite element analysis has suggested that stemless implants may theoretically decrease stress shielding. The purpose of this study was to assess the radiographic proximal humeral bone adaptations seen following stemless anatomic total shoulder arthroplasty.

Methods: A retrospective review of 152 prospectively followed stemless total shoulder arthroplasty utilizing a single implant design was performed.

Biomechanical analyses of pterygotid sea scorpion chelicerae uncover predatory specialisation within eurypterids.

Eurypterids (sea scorpions) are extinct aquatic chelicerates. Within this group, members of Pterygotidae represent some of the largest known marine arthropods. Representatives of this family all have hypertrophied, anteriorly-directed chelicerae and are commonly considered Silurian and Devonian apex predators.

Examining abnormal Silurian trilobites from the Llandovery of Australia.

Abnormal trilobites present insight into how arthropods with fully biomineralised exoskeletons recovered from injuries, genetic malfunctions, and pathologies. Records of abnormal Silurian trilobites in particular show an abundance of specimens with teratologies and a limited record of injuries. Here we expand the record of abnormal Silurian trilobites by presenting seven new abnormal specimens of from the early Silurian (Llandovery, Telychian) Cotton Formation, New South Wales.

A new bilaterally injured trilobite presents insight into attack patterns of Cambrian predators.

Durophagous predation in the Cambrian is typically recorded as malformed shells and trilobites, with rarer evidence in the form of coprolites and shelly gut contents. Reporting novel evidence for shell-crushing further expands the understanding of where and when in the Cambrian durophagy was present. To expand the current documentation and present new records of malformed trilobites from the Cambrian of China, we present an injured () from the lower Cambrian Balang Formation, western Hunan, South China.

Prevalence and factors of work-related musculoskeletal disorders among hand surgeons.

Background: The nature of tasks required by hand surgeons require both forceful and repetitive maneuvers, thus subjecting these surgeons to the risk of musculoskeletal (MSK) injuries during their years in practice.

Aim: To assess the prevalence, characteristics and impact of MSK disorders among hand surgeons.

Methods: A modified version of the physical discomfort survey was sent to surgeons who were members of the American Society for Surgery of the Hand e-mail.

An earliest Triassic age for and comments on synchrotron tomography of Gondwanan horseshoe crabs.

Constraining the timing of morphological innovations within xiphosurid evolution is central for understanding when and how such a long-lived group exploited vacant ecological niches over the majority of the Phanerozoic. To expand the knowledge on the evolution of select xiphosurid forms, we reconsider the four Australian taxa: , and . In revisiting these taxa, we determine that, contrary to previous suggestion, arose after the Permian and the origin of over-developed genal spine structures within Austrolimulidae is exclusive to the Triassic.

Terrible triad injuries are no longer terrible! Functional outcomes of terrible triad injuries: a scoping review.

Background: The terrible triad injury (TTI) of the elbow is a combination of a posterolateral dislocation of the elbow joint combined with fractures of the radial head and coronoid process most often caused by a fall on an outstretched hand. The injury pattern was named for its poor outcomes and high complication rates following surgical repair, but increased understanding of elbow anatomy and biomechanics has led to the development of standardized surgical protocols in an attempt to improve outcomes. Most existing literature on terrible triad injuries is from small retrospective cohort studies and surgical techniques to improve outcomes.

Trabecular bone density distribution in the scapula of patients undergoing reverse shoulder arthroplasty.

Background: To improve implant survival after reverse shoulder arthroplasty (RSA), surgeons need to maximize screw fixation. However, bone density variation and distribution within the scapula are not well understood as they relate to RSA. The three columns of bone in the scapula surrounding the glenoid fossa are the lateral border, the base of the coracoid process, and the spine of the scapula.