Morphometrics for sports mechanics: Showcasing tennis racket shape diversity.

Tennis racket design has changed from its conception in 1874. While we know that modern tennis rackets are lighter and have larger heads than their wooden predecessors, it is unknown how their gross shape has changed specifically. It is also unknown how racket shape is related to factors that influence performance, like the Transverse and Polar moments of inertia. The aim of this study was to quantify how tennis racket shape has changed over time, with a view to furthering our understanding of how such developments have influenced the game. Two-dimensional morphometric analysis was applied to silhouettes extracted from photographs of 514 rackets dating from 1874 to 2017. A principal component analysis was conducted on silhouette outlines, to allow racket shape to be summarised. The rackets were grouped by age and material for further analysis. Principal Component 1 accounted for 87% of the variation in racket shape. A pairwise Pearson's correlation test indicated that head width and length were both strongly correlated to Principal Component 1 (r = 0.916 & r = 0.801, p-values<0.001). Principal Component 1 was also correlated to the Polar (r = 0.862, p<0.001) and Transverse (r = -0.506, p<0.001) moments of inertia. Racket age and material had a medium (p<0.001, η2p = 0.074) and small (p = 0.015, η2p = 0.017) effect on Principal Component 1, respectively. Mean racket shapes were also generated from the morphometric analyses for the material and age groupings, and we consider how these shape changes may have influenced performance and injury risk. These mean shape groupings could support the development of models, such as finite element analysis, for predicting how historical developments in tennis equipment have affected performance and injury risk.

Plasmon Waveguide Resonance: Principles, Applications and Historical Perspectives on Instrument Development.

Plasmon waveguide resonance (PWR) is a variant of surface plasmon resonance (SPR) that was invented about two decades ago at the University of Arizona. In addition to the characterization of the kinetics and affinity of molecular interactions, PWR possesses several advantages relative to SPR, namely, the ability to monitor both mass and structural changes. PWR allows anisotropy information to be obtained and is ideal for the investigation of molecular interactions occurring in anisotropic-oriented thin films. In this review, we will revisit main PWR applications, aiming at characterizing molecular interactions occurring (1) at lipid membranes deposited in the sensor and (2) in chemically modified sensors. Among the most widely used applications is the investigation of G-protein coupled receptor (GPCR) ligand activation and the study of the lipid environment's impact on this process. Pioneering PWR studies on GPCRs were carried out thanks to the strong and effective collaboration between two laboratories in the University of Arizona leaded by Dr. Gordon Tollin and Dr. Victor J. Hruby. This review provides an overview of the main applications of PWR and provides a historical perspective on the development of instruments since the first prototype and continuous technological improvements to ongoing and future developments, aiming at broadening the information obtained and expanding the application portfolio.

A historical review of the evolution of nasal lavage systems.

BACKGROUND: Nasal lavage is an ancient practice that still has a fundamental role in the management of sinonasal conditions. The history related to these devices is extensive and remarkable. By reviewing it, it is hoped that a broader view can be achieved on what is currently possible with nasal lavage and how advances may be made in the future. METHODS: A careful review of different sources, such as ancient manuscripts, registered patents and scientific papers, was conducted to achieve a thorough examination of the history related to nasal rinsing devices. CONCLUSION: Nasal lavage has evolved significantly since first considered for medical use and has always played a central role in the treatment of patients with sinonasal conditions. Further innovation is still necessary to surmount the shortcomings of current nasal lavage systems.

Wearable electrochemical biosensors in North America.

Tremendous research and commercialization efforts around the world are focused on developing novel wearable electrochemical biosensors that can noninvasively and continuously screen for biochemical markers in body fluids for the prognosis, diagnosis and management of diseases, as well as the monitoring of fitness. Researchers in North America are leading the development of innovative wearable platforms that can comfortably comply to the human body and efficiently sample fluids such as sweat, interstitial fluids, tear and saliva for the electrochemical detection of biomarkers through various sensing approaches such as potentiometric ion selective electrodes and amperometric enzymatic sensors. We start this review with a historical timeline overviewing the major milestones in the development of wearable electrochemical sensors by North American institutions. We then describe how such research efforts have led to pioneering developments and are driving the advancement and commercialization of wearable electrochemical sensors: from minimally invasive continuous glucose monitors for chronic disease management to non-invasive sweat electrolyte sensors for dehydration monitoring in fitness applications. While many countries across the globe have contributed significantly to this rapidly emerging field, their contributions are beyond the scope of this review. Furthermore, we share our perspective on the promising future of wearable electrochemical sensors in applications spanning from remote and personalized healthcare to wellness.

Versatile use of microliths as a technological advantage in the miniaturization of Late Pleistocene toolkits: The case study of Neve David, Israel.

The miniaturization of stone tools, as reflected through the systematic production of bladelets and bladelet tools (microliths), characterized many industries of the Late Pleistocene, with the Levantine Epipalaeolithic serving as a well-studied example. It is commonly held that microliths were used as modular inserts in composite projectiles, while their incorporation in other tools for different tasks is generally overlooked, the latter aspect being the main focus of this paper. We present here a more inclusive approach through a case study of the Geometric Kebaran (Middle Epipalaeolithic, ca. 18,500-15,000 cal BP) site of Neve David, Mount Carmel, Israel. Recent excavations at the site exposed a variety of features, and one well-preserved shallow pit provided a large lithic assemblage with ca. 90 microliths. We studied this assemblage using both the low- and high- magnification use-wear protocols, accompanied by a range of experiments. Our results show that a) the fragmentation rate is very high in this assemblage (ca. 90%), b) most of the microliths have identifiable use-wear, c) the microliths were commonly used as inserts in composite projectiles, d) many microliths were used for functions not related to weaponry and hunting, such as wood-working, weed harvesting and meat processing. These findings strongly support the suggestion that the small insets, regardless of their specific type (trapeze, rectangle, backed/retouched bladelet), were used in a wide variety of composite tools. We argue that such a versatile approach and flexibility in the use of microliths reflect a technological advantage where a minimal set of microlithic types, produced in large numbers, could provide the required elements for weapons, as well as for a variety of cutting, processing and harvesting tools needed for mundane tasks at a large Middle Epipalaeolithic camp.

The electroshock triangle: disputes about the ECT apparatus prototype and its display in the 1960s.

In the early 1960s, a climate of public condemnation of electroconvulsive therapy was emerging in the USA and Europe. In spite of this, the electroshock apparatus prototype, introduced in Rome in 1938, was becoming hotly contended. This article explores the disputes around the display of the electroshock apparatus prototype in the summer of 1964 and sheds new light on the triangle of personalities that shaped its future: Karl and William Menninger, two key figures of American psychiatry in Topeka; their competitor, Adalberto Pazzini, the founder of the Sapienza Museum of the History of Medicine in Rome; and, between them, Lucio Bini, one of the original inventors of ECT, who died unexpectedly that summer.

Oftalmoscopio de Benson / Benson's ophthalmoscope

No disponible

A brief history of contact X-ray brachytherapy 50 kVp.

Contact X ray brachytherapy 50 kVp was initiated in the 1930s with the Siemens unit and popularized with the Philips unit in the 1950s. A renaissance was seen in the early 2000s with the Intrabeam™ unit for breast IORT. Presently the Papillon™ systems thanks to its high dose rate (>10Gy/mn) can be used to treat breast (IORT), skin, eyelid and rectal cancers. Future developments are expected to consolidate the place of contact radiotherapy as a safe and efficient treatment for accessible early tumors.

Philip Drinker versus John Haven Emerson: Battle of the iron lung machines, 1928-1940.

The "iron lung," originally known as the Drinker respirator, was developed in 1928 by Dr Philip Drinker and Dr Louis Agassiz Shaw to improve the respiration of polio patients. In 1931, John Haven Emerson, an inventor from Cambridge, MA, enhanced the design of the Drinker respirator and introduced a new and highly improved model of the iron lung that was cheaper and significantly lighter. Dr Drinker eventually filed a lawsuit against Emerson for alleged patent infringement. In his defense, Emerson argued that devices that help save human lives should be widely accessible to all patients. He also questioned the novelty of Drinker's design, claiming that Drinker's device comprised of patented technology that existed since the late 1800s, and that he therefore did not have full ownership of the machine's intellectual property. Ultimately, the case backfired on Drinker, as he not only lost the court case but also lost the entire panel of patents that were in his possession.

The History of Surgical Staplers: A Combination of Hungarian, Russian, and American Innovation.

Since their development in 1908, surgical staplers have been used as a method of "mechanical suturing" in efforts to divide hollow viscera and create anastomoses in an efficient and sterile manner. The concept for the surgical stapler was first developed by Humér Hultl, a Hungarian professor and surgeon, and designed by Victor Fischer, a Hungarian businessman and designer of surgical instruments. The design was highly acclaimed; however, it was bulky, cumbersome, and expensive to manufacture. In 1920, Aladár Petz, a student of Hultl, incorporated two innovations to the Fischer-Hultl stapler to create a more lightweight model, which was named the Petz clamp. In 1934, Friedrich of Ulm designed what would be the predecessor to the modern-day linear stapler. In the 1950s, Russian and American staplers began to emerge. Throughout the 1960s, a variety of stapling instruments were developed in the United States, manufactured by the United States Surgical Corporation. In the 1970s, Johnson & Johnson Ethicon brand joined the market. The United States Surgical Corporation was later bought by Tyco Healthcare and became Covidien in 2007. Through the collaboration of Felicien Steichen, Mark Ravitch, and Leon Hirsch, surgical staplers were further modified to incorporate interchangeable cartridges with various designs. With the advent of minimally invasive surgery began production of laparoscopic surgical staplers. Since its inception, the surgical stapler has provided a means to efficiently create safe and effective visceral and vascular anastomoses. The surgical stapler design continues to evolve while still maintaining the basic principles that were implemented in the original design.

External fixation of the lower extremities: Biomechanical perspective and recent innovations.

The concept of supporting fractured long bones externally with mechanical fixation has been evidentially applied for over 2000 years, and since been expanded on in the mid-19th century by percutaneous bone fixation. Surgical techniques, external fixator systems, and materials have made continued progress since. The benefits of traditional external fixation have been enhanced in recent years with the introduction of hexapod-style fixators, innovative configurations, and pin modifications, among other things. It is generally agreed upon that biomechanical testing of advancements in external fixation must be inclusive of transverse or torsional loading to simulate construct behaviour in realistic scenarios. Biomechanical studies indicate that hexapod-style fixators show comparable axial stiffness to Ilizarov-style systems and improved performance under torsional and transverse forces. The addition of configuration elements to fixators, inclusion of certain carbon fibre chemical compositions, and techniques intended to augment ring thickness have also been investigated, in hopes of increasing construct stiffness under loading. Novel external fixators attempt to broaden their applications by rethinking bone mounting mechanisms and either expanding on or simplifying the implementation of 3D bone segment transport for corrective osteotomy. Older and seemingly unconventional fixation techniques are being rediscovered and evolved further in order to increase patient comfort by improving everyday usability. The development of new pin coatings can potentially enhance the pin-bone interface while lowering infection rates typically expected at thicker soft tissue envelopes. Although complication, malunion, and nonunion rates have decreased over the past 50 years, the clinical results of external fixation today can still be optimized. Unsatisfactory healing in the lower extremities has especially been reported at locations such as the distal tibia; however, advancements such as osteoinductive growth hormone treatment may provide improved results. With the current progression of technology and digitization, it is only a matter of time before 'smart', partly-autonomous external fixation systems enter the market. This review article will provide a versatile overview of biomechanically proven fixator configurations and some carefully selected innovative systems and techniques that have emerged or been established in the past two decades.