Amorphous Silicon Oxynitride-Based Powders Produced by Spray Pyrolysis from Liquid Organosilicon Compounds

Silicon oxynitrides (SiO_xN_y) have many advantageous properties for modern ceramic applications that justify a development of their new and efficient preparation methods. In the paper, we show the possibility of preparing amorphous SiO_xN_y-based materials from selected liquid organosilicon compounds, methyltrimethoxysilane CH₃Si(OCH₃)₃ and methyltriethoxysilane CH₃Si(OC₂H₅)₃, by a convenient spray pyrolysis method. The precursor mist is transported with an inert gas or a mixture of reactive gases through a preheated tube reactor to undergo complex decomposition changes, and the resulting powders are collected in the exhaust filter. The powders are produced in the tube at temperatures of 1200, 1400, and 1600 °C under various gas atmosphere conditions. In the first option, argon Ar gas is used for mist transportation and ammonia NH₃ gas serves as a reactive medium, while in the second option nitrogen N₂ is exclusively applied. Powder X-Ray Diffraction (XRD) results confirm the highly amorphous nature of all products except those made at 1600 °C in nitrogen. SEM examination shows the spheroidal particle morphology of powders, which is typical for this method. Fourier Transform Infrared (FT-IR) spectroscopy reveals the presence of Si–N and Si–O bonds in the powders prepared under Ar/NH₃, whereas those produced under N₂ additionally contain Si–C bonds. Raman spectroscopy measurements also support some turbostratic free carbon C in the products prepared under nitrogen. The directly determined O- and N-contents provide additional data linking the process conditions with specific powder composition, especially from the point of view of oxygen replacement in the Si–O moieties formed upon initial precursor decomposition reactions by nitrogen (from NH₃ or N₂) or carbon (from the carbonization of the organic groups).     

The Impact of the Lubricant Dose on the Reduction of Wear Dies Used in the Forging Process of the Valve Forging

The paper presents the results of research on the influence of the settings of lubrication and cooling system parameters (solenoid valve opening time and lubricant feed pressure in terms of its quantity) in order to select the optimal lubricating conditions and thus reduce the wear of the dies used in the first forging operation of the valve forging made of high-nickel steel. Based on the observation of lubrication in the industrial process, it was found that a significant part of the lubricant fails to reach the die cavity, reaching the outside of it, which causes die wear due to seizure resulting from adhesion of the forging material to the tool surface as well as high lubricant consumption and dirt in the press chamber. The authors proposed their own mobile lubricating and cooling system, which allows for a wide range of adjustments and provided with automatic cleaning procedures of the entire system, unlike the fixed lubrication system used so far in the industrial process. First, tests were carried out in laboratory conditions to determine the highest wettability and the lubricant remaining inside the tool cavity. These tests determined the lubrication system parameter settings that ensured that the greatest amount of lubricant remains in the cold die cavity without the forging process. Then, to verify the obtained results, tests were carried out in the industrial process of hot die forging of valve forgings for short production runs of up to 500 forgings. The results were compared with the measurement of changes in the geometry of tools and forgings based on 3D scanning and surface topography analysis with the use of SEM (Scanning Electron Microscope). For the best results (the variant of the setting of the dose and the time of exposure to lubricant), the forging process was carried out with the use of a new tool up to the maximum service life.     

Community-based falls prevention: lessons from an Interprofessional Mobility Clinic

Falls are a common and serious risk with an aging population. Chiropractors commonly see firsthand the effects of falls and resulting injuries in their senior patients and they can reduce falls risk through active screening. Ongoing research has provided proven approaches for making falls less likely. Screening for falls should be done yearly for all patients 65 years and older or in those with a predisposing medical condition. Additional specific falls prevention professional education would enable the chiropractor to best assist these patients. Collaboration and communication with the patient’s family physician offers an opportunity for improved interprofessional dialogue to enhance patient care related to falls risk. Frequently falls prevention strategies are implemented by an interprofessional team. Chiropractors increasingly contribute within multidisciplinary teams. Collaboration by the chiropractor requires both simple screening and knowledge of health care system navigation. Such awareness can permit optimal participation in the care of their patient and the best outcome.     

Bioreplicated visual features of nanofabricated buprestid beetle decoys evoke stereotypical male mating flights

Recent advances in nanoscale bioreplication processes present the potential for novel basic and applied research into organismal behavioral processes. Insect behavior potentially could be affected by physical features existing at the nanoscale level. We used nano-bioreplicated visual decoys of female emerald ash borer beetles (Agrilus planipennis) to evoke stereotypical mate-finding behavior, whereby males fly to and alight on the decoys as they would on real females. Using an industrially scalable nanomolding process, we replicated and evaluated the importance of two features of the outer cuticular surface of the beetle’s wings: structural interference coloration of the elytra by multilayering of the epicuticle and fine-scale surface features consisting of spicules and spines that scatter light into intense strands. Two types of decoys that lacked one or both of these elements were fabricated, one type nano-bioreplicated and the other 3D-printed with no bioreplicated surface nanostructural elements. Both types were colored with green paint. The light-scattering properties of the nano-bioreplicated surfaces were verified by shining a white laser on the decoys in a dark room and projecting the scattering pattern onto a white surface. Regardless of the coloration mechanism, the nano-bioreplicated decoys evoked the complete attraction and landing sequence of Agrilus males. In contrast, males made brief flying approaches toward the decoys without nanostructured features, but diverted away before alighting on them. The nano-bioreplicated decoys were also electroconductive, a feature used on traps such that beetles alighting onto them were stunned, killed, and collected.Biomimicry of insect visual communication signals has received much recent attention, with growing interest in nanofabrication processes that result in artificially produced structural colors (1) such as those emanating from the ridges on butterfly wing scales (2). The fidelity of the nanoreplication of visual signals with communication value to such organisms has been underexplored, however. Visually induced behavior in arthropods often integrates color and edge-motion detection, with interactions often involving a variety of biotic and abiotic entities, making it difficult to reproduce experimentally (3).Bioreplication of visual signaling structures might be manipulated so as to provide insight into the mechanisms of such signaling processes; however, all currently known examples of bioreplicated nanostructures that have been created to affect behavior involve unicellular movements across particular textured environments (4–7), rather than directed to evoke responses of specialized sensory organs of more complex multicellular organisms. Bioreplicated structures emitting behaviorally effective visual cues also may be useful for such practical purposes as the monitoring and detection of pest species, but the communication efficacy of the bioreplica needs to be validated under field conditions using naturally occurring (i.e., wild) populations.In contrast, biomimicry of chemical signals, such as insect pheromones, has been a burgeoning field for more than half a century. Synthetically reproduced pheromones have been successfully applied under field conditions to manipulate insect behavior for invasive species pest detection, population monitoring of endemic species, and disruption of mating. Thousands of studies have described the essential components of nanoscale levels (nanograms) of semiochemical signals that trigger behavioral responses, such as upwind flight for mating (8), alarm responses (9), and trail following (10). Furthermore, neurophysiological techniques have elucidated how these signals are transduced by peripheral sensory organs (11) and integrated into odor sensations in the higher processing centers of the insect brain (12). In the realm of applied science, these insights have led to trapping protocols for pest population detection, attract-and-kill protocols, and mating disruption (13). Visually attractive features of trapping technologies generally have not been approached with such rigor, however, and are usually optimized by simple manipulations of trap colors without efforts to understand the underlying mechanisms of visual attraction.In an effort to initiate such an approach to manipulation of visual signaling systems, we used an industrially scalable nano-bioreplication technique (14) to produce high-fidelity replicas of the structural features of the cuticle of the hard wing covers (elytra) of an invasive buprestid beetle pest, the emerald ash borer (Agrilus planipennis). This species is a tree-killing pest of Asian origin whose visual signal is emitted by the elytra of a female at rest on an ash leaf in direct sunlight, which triggers attraction of flying males that are patrolling the canopy. Male responses unfold as rapid flights toward the females from heights of up to 2 m, usually terminating with the males alighting directly on the females and attempting to copulate (15). This “paratrooper” descent behavior by flying A. planipennis males in the field can be repeatedly evoked by affixing dead A. planipennis females to ash leaves (15, 16). Furthermore, various other potentially invasive European and North American tree-feeding Agrilus species have been observed performing similar stereotypical inflight descents onto dead beetle decoys affixed to the leaves of preferred host trees (17, 18). Such approaches are often seen to congeneric, heterospecific targets. One such species, the two-spotted oak borer, Agrilus biguttatus, that is similar in size and habits to A. planipennis is known to kill oak trees within its native range in Europe (19), particularly after drought (20) or defoliation events (21).The base colors of many metallic-colored beetles, including buprestid beetles (Fig. 1A), are known to be structurally produced by the repeated alternation of cuticle layers (Fig. 1D) with different refractive indices (22, 23). This periodically multilayered assemblage functions as a quarter-wave Bragg stack reflector in a particular spectral regime (2) and is thus highly effective for creating a color of narrow specificity in sunlight, unlike many naturally occurring pigments. The reflected light is also affected by regular fine-scale topographic features of the surface, including thousands of sharp spicules each emitting green to yellow colors, which are further scattered by numerous spines (Fig. 1 B and C). Many of the physical attributes of the A. planipennis cuticle that produce its attractive visual signal have been replicated by a process that involves the stamping of a polymer quarter-wave Bragg stack reflector with a set of dies cast from the actual elytra of a female A. planipennis (Fig. 2) (14).Open in a separate windowFig. 1.Structural color and surface topography of A. planipennis wings. (A) Optical microscopy showing a dorsal view of the beetle elytron. (B) Higher-magnification optical microscopy showing spines and cilia. (C) Scanning electron micrograph showing a higher-resolution image of the surface topography. (D) Transmission electron micrograph of a cross-section of an elytron, showing four alternating layers of differing refractive indices. (C and D are reprinted with permission from ref. 14.)Open in a separate windowFig. 2.Nano-bioreplicated decoy characteristics. (A) Optical microscopy of the nickel die. (B) Scanning electron micrograph of a nickel die used for bioreplication, showing a similar structure as the A. planipennis surface (Fig. 1), but without the cilia. (C) Optical microscopy of the dorsal view of a nano-bioreplicated A. planipennis decoy that reproduces the surface structure of the beetle and is colored by metallic paint. (A and B are reprinted with permission from ref. 14.)Here we report on direct field observations of A. planipennis and A. biguttatus male behavior toward natural beetle decoys versus three types of synthetic decoys with varying degrees of verisimilitude with respect to the fidelity of bioreplication. These synthetic decoys included: (i) a bioreplicated decoy created by a nanomolding process and colored with a polymer functioning as a Bragg reflector; (ii) another bioreplicated decoy created by a nanomolding process and colored with a metallic green paint; and (iii) a 3D-printed decoy consisting of a smooth polymer surface without a nanomolded bioreplicated surface structure, also colored with green metallic paint. We investigated whether the nanomolding process could create light-scattering patterns similar to those of real decoys by observing light emissions resulting from the application of a white laser to the surfaces of real and synthetic decoys in a dark room. We hypothesized that a sufficient degree of verisimilitude with respect to color and fine-scale topological features of the elytra could be achieved through the bioreplication process to elicit inflight mating approaches and landings similar to those evoked by real beetles. We also incorporated the bioreplicated decoys into a trapping system in which the electroconductive properties of the decoy are used to electrocute male beetles when they approach and alight on the decoys.     

Intravenous unfractionated heparin dosing in obese patients using anti-Xa levels

There is limited guidance on intravenous dosing of unfractionated heparin in obese patients. The purpose of this study was to determine the efficacy and safety of a standard unfractionated heparin (UFH) protocol in obese patients based on total body weight (TBW) or adjusted body weight (ABW) to reach two consecutive therapeutic anti-Xa levels. This was a retrospective observational cohort study conducted in a large academic medical center. Adults received a standard UFH protocol between January 1, 2013 to December 31, 2015. Inclusion criteria included age ≥ 18 years of age, weight ≥ 100 kg with a BMI ≥ 30 kg/m², and received intravenous UFH. Patients were excluded if they received an alternative UFH protocol, received?<?24 h of the standard UFH protocol, or had inadequate compliance to protocol. Out of the 131 patients included, 109 patients reached two consecutive therapeutic UFH levels within 96 h. The average time to two consecutive therapeutic UFH levels was 29.4 h and 27.6 h in patients dosed by TBW and ABW, respectively (95% CI ??4.63 to 8.11; P?=?0.93). Safety outcomes included major bleeding, overt bleeding, or death events between patients dosed by TBW compared to ABW, (p?=?0.61, p?=?1.0, p?=?1.0, respectively). Dosing intravenous UFH based on TBW or ABW resulted in similar times to therapeutic anti-Xa levels and safety outcomes. The data provided suggests using either TBW or ABW in obese patients is as effective and safe to use.

     

The efficacy and safety of Grafix® for the treatment of chronic diabetic foot ulcers: results of a multi‐centre,controlled, randomised,blinded, clinical trial

In a randomised, controlled study, we compared the efficacy of Grafix^®, a human viable wound matrix (hVWM) (N = 50), to standard wound care (n = 47) to heal diabetic foot ulcers (DFUs). The primary endpoint was the proportion of patients with complete wound closure by 12 weeks. Secondary endpoints included the time to wound closure, adverse events and wound closure in the crossover phase. The proportion of patients who achieved complete wound closure was significantly higher in patients who received Grafix (62%) compared with controls (21%, P = 0·0001). The median time to healing was 42 days in Grafix patients compared with 69·5 days in controls (P = 0·019). There were fewer Grafix patients with adverse events (44% versus 66%, P = 0·031) and fewer Grafix patients with wound‐related infections (18% versus 36·2%, P = 0·044). Among the study subjects that healed, ulcers remained closed in 82·1% of patients (23 of 28 patients) in the Grafix group versus 70% (7 of 10 patients) in the control group (P = 0·419). Treatment with Grafix significantly improved DFU healing compared with standard wound therapy. Importantly, Grafix also reduced DFU‐related complications. The results of this well‐controlled study showed that Grafix is a safe and more effective therapy for treating DFUs than standard wound therapy.