Type Of Liner Research Articles

Bacterial comparison study of prosthetic liners.

Amputee patients in low-resource settings face a heightened risk of skin infections at the skin-liner interface of their residual limb, which can develop into a variety of serious complications. Most research comparing prosthetic liners has focused on mechanical and aesthetic properties. However, the relative propensity of different liner types to host bacterial growth has yet to be explored. To address this question, we performed a bacterial comparison study across a traditional sock-EVA combination liner, an advanced Ossur Iceross silicone liner, and a novel silicone liner designed for low-resource hospitals in developing nations. We cultured Staphylococcus aureus within a novel physical model of the skin-liner interface, incorporating a replicate skin layer suspended over a self-regulating heat source. After culturing bacteria for 24 h, we collected and quantified cells in solution. Statistical analysis of the bacterial growth concentration from 9 trials revealed relative consistency of growth across the 3 liner types, suggesting that none of the liners pose heightened risks of infection, relative to the others. These results suggest that certain innovative prosthetic materials may safely be considered for fabrication of prosthetic liners in low-resource environments. The in vitro skin-liner model and test method for bacterial growth characterization introduced herein may be useful for future dermatological simulations.

Does Equestrian Helmet Type Affect Head Injury? A Study on Equestrian Helmet Use Among Collegiate Athletes.

To characterize helmet use, head injury risk, and to examine rider-related factors that influence these variables. Cross-sectional study. The University of Alabama at Birmingham Equestrian Sports Medicine Collaborative. In total, 357 equestrians competing at the collegiate level participated in this study. χ2 tests were used to evaluate potential associations between a rider's experience level, riding style, and use of helmet designed with MIPS with number of falls, past head injuries, and helmet use frequency. Data regarding helmet use and equestrian-related injuries were collected. χ2 analysis was used to determine potential associations. More than 50% of athletes reported falling off a horse during the course of 1 year. Head injuries occurred with high frequency. Concussion was the most frequently reported type. More than 50% of athletes with self-reported concussion denied receiving medical treatment. The risk of head injury was similar across helmet brands, and between helmets with Multi-Directional Impact Protection System (MIPS) and those without. Riders with the most experience were less likely to report sustaining a head injury than those with less experience. Contrary to current safety guidelines, 78% of equestrians said that they would not replace their helmet after every fall. Collegiate equestrians have a high risk of fall-related traumatic head injury. Despite this risk, they report helmet use practices that are not in line with current recommendations regarding helmet replacement. This suggests thatmany of the athletes are using protective equipment that does not adequately protect against head injury. Neither helmet brand nor liner type was associated with lower rate of head injury.

Was Palaeolake Messel a death-trap? Insight from modern bat drownings and decay experiments

AbstractThe Messel Pit is an ancient maar lake that preserves an ecosystem from the last greenhouse phase of Earth’s climate with exceptional fidelity. There are two main competing hypotheses to explain the occurrence of animal fossils at Messel: asphyxiation in layers of heavy, toxic gases like carbon dioxide, and death following ingestion of surface water contaminated by cyanobacterial toxins. Both hypotheses imply mortality much higher than the null hypothesis of accidental death, for instance by drowning. We tested these hypotheses amongst bats by recourse to a unique survey on bats that drowned in modern swimming pools. We further conducted experiments on the fate of fresh bat carcasses that simulate drowning. Finally, we estimated the annual rate of bat fossil production at Messel. Overall, there are few good surveyed predictors of whether bats drown in swimming pools: most physical parameters like pool size or the height and distance of obstructions were not associated with mortality, although pool liner type would be a good candidate parameter for future study. In our experiments, carcasses with water-filled lungs tend to sink more quickly than those with air-filled lungs; all carcasses that initially sink “bloat and float” at shallow depths, but all floaters eventually disarticulate and sink within days to weeks. Our estimates of annual bat mortality at Palaeolake Messel are of the same order of magnitude as mortality in swimming pools. Mass mortality horizons for vertebrates are very rare at Messel. In sum, our quantitative analyses provide no evidence that bat mortality at Messel rises above background levels.

Complementary use of analytical equations and numerical models for composite liner designs

The finite element (FE) method is used to identify limitations and extend the applicability of an analytical solution for leakage through holed wrinkles in composite liners. The limiting assumption in the analytical model is relaxed based on FE results, providing a means of obtaining good agreement through the two methods over a wide spectrum of cases. Despite the flexibility of the FE, the analytical model has the advantage of readily accommodating a wide range of dimensions and material properties that, even with a very large mesh, may be difficult to analyze using FE. In addition, the analytical equation is well-suited for Monte Carlo simulation. This is illustrated by the use of the modified analytical equation and the Monte Carlo simulations to compare the performance of two types of composite liners currently approved for use in Chinese landfills with a generic design in Canada and other parts of the world. It is shown that even with a relatively small number of holed wrinkles leakage through the geomembrane composite liner can differ by up to two orders of magnitude between composite liners considered to be equivalent. The paper also notes the need to revise regulations to reflect the evolution of knowledge.

Analysis of Farmers’ Perceptions on Sealing Techniques for Runoff Harvesting Ponds: A Case Study from Burkina Faso

Water conservation in arid and semi-arid regions faces significant challenges due to low and irregular rainfall, worsened by climate change, which negatively affects rain-fed crop productivity. Various techniques, including supplemental irrigation using runoff harvesting ponds, aim to address these issues but often suffer from water loss due to infiltration, influenced by the pond liner type. This study uses a factorial analysis to assess the farmers’ perceptions of four pond sealing techniques. Using the Waso-2 method, a survey conducted in 2022 among 41 rainwater harvesting pond owners across three regions of Burkina Faso revealed that farmers prioritized impermeability and ease of maintenance over cost and availability. Concrete, scoring 16/20, was the most preferred, chosen by over 75% of farmers for its durability and resistance to weathering, despite its high cost. Geomembrane, with a score of 12/20, was valued for its waterproofing properties but had durability concerns. Clay, although cheap and available, scored 8/20 due to poor waterproofing on unstable ground. Bitumen, the least favored with a score of 6/20, was hindered by scarcity and lack of familiarity. To enhance supplemental irrigation in Burkina Faso and similar regions, waterproof concrete or durable geomembrane liners are recommended. Further research into improving bitumen and clay liners is also suggested. These findings provide key insights into farmers’ preferences, offering guidance for developing effective water conservation strategies to boost agricultural productivity and address food security challenges in the context of climate change.

Feasibility of an acoustic liner applied to a Fenestron: simulation

A helicopter's anti-torque system is a significant contributor to radiated noise. The Fenestron, used on Airbus Helicopters, allows to mitigate the anti-torque noise by masking effect and modulation of the blade distribution. However, unlike aircraft engine nacelles, it does not contain acoustic liners inside the duct to absorb the noise radiated by the rotor blades. This paper describes: first, the FEM modelization of the noise radiation for a 1/3-scale fenestron mock-up at the 1st BPFs, in static conditions; second, the assessment of the effect of an absorbing treatment introduced inside the collector or the diffuser and defined by its acoustic specific impedance; third, the design optimization applied to different acoustic liner types, adapted to the diffuser of the mock-up. Because of the limited duct length, forward and afterward radiations interact, generating interference pressure patterns. Several types of liners (conventional and unconventional), designed to deliver a high absorption, appear adapted to dimensional constraints: SDOF or DDOF type, with a perforated plate above cavities or based on the concept LEONAR ("Long Elastic Open Neck Acoustic Resonator"). Another paper completes the study with (aero-)acoustic tests, applied to elementary samples to validate the impedance target, and performed in an anechoic room with the mock-up.

Feasibility of an acoustic liner applied to a Fenestron: experimentation

A helicopter's anti-torque system is a significant contributor to radiated noise. The Fenestron, used on Airbus Helicopters, allows to mitigate the anti-torque noise by masking effect and modulation of the blade distribution. However, unlike aircraft engine nacelles, it does not contain acoustic liners inside the duct to absorb the noise radiated by the rotor blades. This paper describes: first, the (aero-)acoustic tests applied to different acoustic liners optimised to be integrated into a 1/3-scale fenestron mock-up, in order to provide a specific impedance (measurement in impedance tube and aeroacoustic bench); second, the configuration of a mock-up installed in an anechoic room, with an acoustic antenna; third, the acoustic pressure mitigation obtained for several diffusers equiped with liners (variation of RPM and pitch for the purpose of the experiment). It appears that the tested liners are likely to provide a high absorption coefficient in a large frequency range and a significant attenuation when installed in the Fenestron mock-up, in accordance with preliminary simulations. Another paper completes the study with a preliminary numerical assessment of the effect of an absorbing treatment introduced inside the collector or the diffuser, and a design optimization applied to different acoustic liner types, adapted to the mock-up.

Rate of revision and wear penetration in different polyethylene liner compositions in total hip arthroplasty: a Bayesian network meta-analysis

The present Bayesian network meta-analysis compared different types of polyethylene liners in total hip arthroplasty (THA) in terms of wear penetration (mm/year) and rate of revision. The type of liners compared were the crosslinked ultra-high molecular weight polyethylene (CPE/UHMWPE), Vitamin E infused highly cross-linked polyethylene (HXLPE-VEPE), modified cross-linked polyethylene (MXLPE), highly cross-linked polyethylene (HXLPE), Cross-linked polyethylene (XLPE). This study was conducted according to the PRISMA extension statement for reporting systematic reviews incorporating network meta-analyses of healthcare interventions. In June 2024, PubMed, Scopus, Embase, Google Scholar, and Cochrane databases were accessed. A time constraint was set from January 2000. All investigations which compared two or more types of polyethylene liners for THA were accessed. Only studies that clearly stated the nature of the liner were included. Data from 60 studies (37,352 THAs) were collected. 56% of patients were women. The mean age of patients was 60.0 ± 6.6 years, the mean BMI was 27.5 ± 2.0 kg/m2. The mean length of follow-up was 81.6 ± 44.4 months. Comparability was found at baseline between groups. XLPE and HXLPE liners in THA are associated with the lowest wear penetration (mm/year) and the lowest revision rate at approximately 7 years of follow-up.

Phosphorus removal in surface flow treatment wetlands for domestic wastewater treatment: Global experiences, opportunities, and challenges

Treatment Wetlands (TWs) are widely used for the treatment of domestic wastewater, with an increasing emphasis on provision of multiple co-benefits. However, concerns remain regarding achieving stringent phosphorus (P) discharge limits, system robustness and resilience, and associated guidance on system design and operation. Typically, where P removal is intended with a passive TW, surface flow (SF) systems are the chosen design type. This study analysed long-term monitoring datasets (2–30 years) from 85 full-scale SF TWs (25 m2 to 487 ha) treating domestic sewage with the influent load ranging from 2.17 to 54,779 m3/d, including secondary treatment, tertiary treatment, and combined sewer overflows treatment. The results showed median percentage removals of total P (TP) and orthophosphate (Ortho P) of 28% and 31%, respectively. Additionally, median areal mass removal rates were 5.13 and 2.87 gP/m2/yr, respectively. For tertiary SF TWs without targeted upstream P removal, 80% of the 44 systems achieved ≤3 mg/L annual average effluent total P. Tertiary SF TWs with targeted upstream P removal demonstrated high robustness, delivering stable effluent TP < 0.35 mg/L. Seasonality in removal achieved was absent from 85% of sites, with 95% of all systems demonstrating stable annual average effluent TP concentrations for up to a 30-year period. Only two out of 32 systems showed a significant increase in effluent TP concentration after the initial year and remained stable thereafter. The impact of different liner types on water infiltration, cost, and carbon footprint were analysed to quantify the impact of these commonly cited barriers to implementation of SF TW for P removal. The use of PVC enclosed between geotextile gave the lowest additional cost and carbon footprint associated with lining SF TWs. Whilst the P-k-C∗ model is considered the best practice for sizing SF TWs to achieve design pollutant reductions, it should be used with caution with further studies needed to more comprehensively understand the key design parameters and relationships that determine P removal performance in order to reliably predict effluent quality.

The Impact of Leg Length and Offset Change on Dislocation Risk Following Primary Total Hip Arthroplasty

BackgroundSoft tissue management in total hip arthroplasty includes appropriate restoration and/or alteration of leg length (LL) and offset to re-establish natural hip biomechanics. The purpose of this study was to evaluate the effect of LL and offset-derived variables in a multivariable survival model for dislocation. MethodsClinical, surgical, and radiographic data was retrospectively acquired for 12,582 patients undergoing primary total hip arthroplasty at a single institution from 1998 to 2018. There were twelve variables derived from preoperative and postoperative radiographs related to LL and offset that were measured using a validated automated algorithm. These measurements, as well as other modifiable and nonmodifiable surgical, clinical, and demographic factors, were used to determine hazard ratios for dislocation risk. ResultsNone of the LL or offset variables conferred significant risk or protective benefit for dislocation risk. By contrast, all other variables included in the multivariable model demonstrated a statistically significant effect on dislocation risk with a minimum effect size of 28% (range 0.72 to 1.54) (sex, surgical approach, acetabular liner type, femoral head size, neurologic disease, spine disease, and prior spine surgery). ConclusionsContrary to traditional teaching and our hypothesis, operative changes in LL and offset did not demonstrate any clinically or statistically significant effect in this large and well-characterized cohort. This does not imply that these variables are not important in individual cases, but rather suggests the overall impact of LL and offset changes is relatively minor for dislocation risk compared to other variables that were found to be highly clinically and statistically significant in this population. These results may also suggest that surgeons do a good job of restoring native LL and offset for patients, which may mitigate their analyzed impact.

Lactic and Acetic Acids in Sour Beers Promote Corrosion During Aluminum Beverage Can Storage

Newer sour beers are often packaged in aluminum cans, but the compatibility of sour beer and its major acids (lactic, acetic) with cans is unclear. In an initial study, commercial sour beers were packaged in cans containing one of four different liners (bisphenol A (BPA) epoxy, two BPA–non-intent (BPA-NI) epoxy, and acrylic). Corrosion, as measured by dissolved aluminum and visual degradation of the liner, was positively correlated with concentrations of lactic acid, acetic acid, and decreased pH value. After 48 wk, aluminum concentrations up to 58 mg/L were observed in one sour beer, or nearly 100-fold greater than typical dissolved aluminum concentrations in non-sour beers. Liner type did not affect corrosion. In a subsequent model sour beer study with two acrylic liners and one BPA-NI liner, molecular SO2 positively correlated with corrosion, but only at concentrations 5-fold higher than the maximum expected in sour beers. Other added components (chloride, copper, ethanol) did not affect corrosion. Addition of acetic, lactic, and phosphoric acid in varying equinormal combinations to a non-sour beer demonstrated that acetic and lactic acids (average dissolved aluminum = 2.54 mg/L following storage) promote corrosion more than phosphoric acid (average dissolved aluminum = 0.47 mg/L). Titratable acidity (TA) correlated well with corrosion, with increased dissolved aluminum observed at TA > 6 g/L as lactic acid equivalents. Organic acid corrosivity was hypothesized to relate to the proportion of acid in its neutral form, and thus these findings are relevant to producers of other beverages with high levels of organic acids.

Comparison of 5-year cup and stem migration between ceramic-on-ceramic and ceramic-on-polyethylene bearing in press-fit total hip arthroplasty: a randomised controlled trial using radiostereometric analysis.

The inelasticity of ceramic bearings might affect primary stability and migration of implants in press-fit total hip arthroplasty (THA). This randomised controlled trial compares migration patterns of the uncemented Delta-TT cup and H-MAX S stem between ceramic and polyethylene liners, up to 5 years follow-up. Patients receiving primary press-fit THA were randomly allocated to a ceramic (n = 28) or polyethylene (n = 25) liner. Migration was measured using model-based radiostereometric analysis (RSA) at baseline and 1.5, 3, 6, 12, 24 and 60 months postoperatively and compared between groups using mixed models statistical analysis. The focus of this study is on the 2- to 5-year migration of the Delta-TT cup and migration during complete follow-up of the H-MAX S stem up to 5-years. At 5-year follow-up, mean (95% CI) proximal cup translation was 0.56 (0.37-0.74) mm in ceramic and 0.58 (0.25-0.90) mm in polyethylene (p = 0.729). The mean change in adduction was 1.05° (0.27-1.82°) in ceramic and 0.78° (-0.16-1.71°) in polyethylene. Mixed modelling showed that all between-group effects were ⩽0.20 mm for translation and ⩽0.22° for rotation at 5 years postoperatively (p ⩾ 0.23). Mean cup migration between 2 and 5 years was limited (all parameters <0.17 mm and <0.30°). At 5-year follow-up, mean stem subsidence was 2.09 mm (0.89-3.29 mm) in ceramic and 2.55 (0.97-4.12) mm in polyethylene. The mean change in internal rotation was 3.69° (1.98-5.40°) in ceramic and 4.01° (2.20-5.81°) in polyethylene. Most stem migration occurred up to 1.5 months, stabilising afterwards. All between-group effects were ⩽0.75 mm for translations and ⩽1.41° for rotations (p ⩾ 0.26). 5-year migration patterns of press-fit cups and stems were similar between ceramic and polyethylene liners. The Delta-TT cup and H-MAX S stem showed secondary stabilisation and remained stable up to 5 years in both groups, which is promising for long-term survival with both liner types. ClinicalTrials.gov (NCT03093038).

INFLUENCE OF MANUFACTURING CHARACTERISTICS OF HIGHLY CROSS-LINKED POLYETHYLENE ON FEMORAL HEAD PENETRATION IN TOTAL HIP ARTHROPLASTY: A TEN- TO 20-YEAR FOLLOW-UP STUDY

Highly cross-linked polyethylene (HXLPE) has decreased wear and revision rates in total hip replacement (THR) at a long-term. However, the effect of HXLPE manufacturing characteristics on femoral head penetration has not been clearly defined yet. We report this single-institution study to investigate the clinical and radiological results of different HXLPE liners in THR.In this retrospective cohort analysis of our prospective database, we identified 904 THRs performed between 2000 and 2013. Seven different HXLPE liner types were assessed: remelted (3), annealed (2), sequentially annealed (1) and vitamin E-infused (1). The linear femoral head penetration rate was measured at six weeks, one year, and annually thereafter, using the Roman Software v1.70 package.Thirty hips were revised for the following reasons: aseptic loosening (11), dislocation (12), periprosthetic femoral fracture (6), and infection (1). No hip was revised for wear or osteolysis. 741 THRs were evaluated for a mean follow-up of 15 years (range, 10 to 20). The mean total penetration 15 years after THR was 0.17 mm in the sequentially annealed, and 0.16 mm in the vitamin E-infused groups, whereas it was 0.26 mm in the melted 95 kGy, 0.27 mm in the melted 5 Mrad and 0.25 mm in the melted 100 kGy groups (p=0.001). From one to 15 years after surgery, the mean wear was 0.206 mm in cups with an acetabular inclination greater than 50º and 0.105 mm in those placed between 35º and 50º (p&lt;0.001).Although HXLPE characteristics can result in a different wear performance in patients undergoing THR at a mean follow-up of 15 years, the clinical results are excellent. The position of the acetabular component can influence on the femoral head penetration of modern HXLPEs. Nevertheless, these patients should continue to be monitored to detect future problems.

Reverse Shoulder Arthroplasty for Proximal Humeral Fractures: Is the Bigliani-Flatow Stem Suitable for Tuberosity Fixation and Healing?

Background/Objectives: The aim of the study was to investigate the clinical, functional, and radiographic results of patients affected by three- or four-part proximal humeral fractures treated with reverse total shoulder arthroplasty, to investigate whether a prosthetic stem nonspecifically designed for fractures (i.e., the Bigliani-Flatow stem) promotes tuberosities' healing, and to evaluate the impact of tuberosity fixation and healing on the outcomes. Methods: Patients' data such as gender, age, side and dominancy, comorbidities, complications during or after surgery, and time lapse between trauma and surgery were prospectively collected. The type of fixation of the stem, the thickness and type of liner, and whether the tuberosities were fixed or not were also recorded. The Constant score weighted on the contralateral limb, QuickDASH, Oxford Shoulder Score, and Subjective Shoulder Value were collected. Tuberosities' healing was assessed with X-rays (anteroposterior, Grashey, and axillary views). Results: Overall, 34 patients were included, with an average follow-up of 42 months. Tuberosities were reinserted in 24 cases and their healing rate was 83%. The mean values were the following: a Constant score of 64, Oxford Shoulder Score of 39, Subjective Shoulder Value of 71, and QuickDASH score of 27. There were no significant differences in the scores or range of motion between patients with tuberosities healed, reabsorbed, or not reattached. There was a better external rotation in the group with healed tuberosities and a longer duration of surgery to reattach tuberosities. Conclusions: The treatment of proximal humerus fractures with the Bigliani-Flatow stem is associated with good clinical and functional results. The healing rate of the tuberosities was high and comparable, if not even better, than the mean rates reported for the stems dedicated to fractures of the proximal humerus and was, therefore, also appropriate for this indication.

Impact of Cerium Oxide Nanoparticles Incorporation on Water Sorption and Solubility of Acrylic-Based Denture Soft Lining Material

Denture soft liners are specifically engineered to enhance patient performance by altering the surfaces of prosthetics that come into touch with the soft tissues within the oral cavity. Acrylic resin Polymethyl methacrylate (PMMA) based and silicone elastomer-based are the two main types of denture soft liners. Nanotechnology was employed as a means to enhance the mechanical qualities of dentures. The primary objective of this investigation was to examine the impact of cerium oxide (CeO2) nanoparticles (NPs) on the water sorption and solubility characteristics of acrylic-based soft liners. The data was subjected to analysis of variance (ANOVA). The surface characteristics were determined using scanning electron microscopy (SEM). This in vitro study demonstrates that including CeO2 NPs at 2% and 3% concentrations does not impact acrylic-based soft lining materials' water sorption and solubility. The solubility of CeO2 is well-recognized to be very low. The results indicated that there were no statistically significant differences between the groups.

Phantom Limb Pain Improvement Post Right Lower Extremity Amputation With a Liner-type Prosthesis and Pharmacotherapy Combination: A Case Report

BACKGROUND: Phantom limb pain is pain in a missing limb postamputation. There is no sufficient evidence for an effective drug therapy, even though various treatment methods have been tried. Apart from drug therapy, mirror therapy, proprioceptive training, and virtual reality, as well as rehabilitation with appropriate orthotics have been tried. Liner-type prostheses use a silicone liner to reduce shear forces between the skin and the orthosis and to maintain suspension function, thereby relieving pain and improving comfort and functionality for the user. CASE REPORT: A 65-year-old man underwent amputation of his right thigh. On the 10th postoperative day, he complained of phantom limb pain centered on the amputation site. Pregabalin was started but did not alleviate his symptoms. After consultation with a physical therapist, the patient began using a liner prosthesis on the 33rd postoperative day. Symptoms gradually lessened, and positive comments were heard from the patient. Pregabalin and duloxetine were administered for a time but were soon reduced. Due to good pain control, the patient was discharged on the 46th postoperative day. After discharge from the hospital, the patient was able to continue treatment as an outpatient without his symptoms worsening, using a liner prosthesis as needed. CONCLUSION: Right thigh amputation is a very physically and emotionally taxing operation for the patient. Phantom limb pain is a difficult symptom to manage, but it must be adequately controlled for the patient. We have achieved phantom limb pain improvement with a combination of pharmacotherapy and a liner prosthesis. We feel a great need for close collaboration with other professions and for a nonpharmacologic approach in addition to pharmacotherapy. KEY WORDS: Phantom limb pain, amputation, pregabalin, duloxetine, liner type prosthesis

3D preoperative predictions of in vivo hip stability and edge loading for neutral and lipped liners.

Hip dislocation is one of the leading causes of failure and revision surgery for total hip arthroplasty. To reduce dislocation rates, lipped liners have been designed with an elevated portion of the rim, to increase jump distance and maintain greater contact area. While it has been documented that lipped liners help reduce dislocation, the objective of this study is to investigate whether lipped liners also help reduce smaller instances of hip micromotion, separation, and edge loading. This study uses an advanced three-dimensionalpreoperative planning tool to analyze 10 patients, each implanted with both a neutral and lipped liner. Patients within the simulation performed stance phase of gait, and each cup was implanted with the rotation center aligned with the preoperative acetabulum center as well as shifted medially by 2, 4, 6, 8, and 10 mm, yielding 120 total simulations. Specific postoperative outcomes-of-interest included specified component offset, resultant in vivo hip forces, hip separation, and contact area to evaluate edge loading. The planner predicted a reduction in hip separation and an increase in articulating contact area for when using a lipped liner compared to a neutral liner. Additionally, regardless of liner type, increases in hip separation corresponded to decreases in contact area, therefore resulting in edge loading of the liner. Together, this indicates that improper component alignment and offsets may lead to an increase in hip separation and edge loading, but the use of a lipped liner may provide improved stability and resistance to this micromotion.

Effect of different cavity liners on nanocomposite resin shear bond strength to dentine.

The effect of different cavity liners on the shear bond strength of nanocomposite to dentin is of interest. A total of sixty extracted caries-free maxillary, mandibular molars were randomly assigned to four groups in the following manner Group 1: control (no cavity liner), group 2: Biodentin, group 3: Apacal ART and Group 4: Giomer. Following the application of different cavity liners based on the groups, restoration was carried out using nanocomposite resin using the total-etch Tetric N bond adhesive. The samples were thereafter subjected to a shear bond strength test at a cross-head speed of 1 mm/min until bond failure occurred, utilizing the universal testing machine. The one-way ANOVA test and the post hoc test were used to evaluate the data for pairwise group comparisons. Compared to the control group, all groups showed lower shear bond strength to dentin, irrespective of the type of liner. Apacal ART showed higher shear bond strength followed by giomer and biodentin. However, there's no apparent statistical difference between the groups.

Forensic profiling of smokeless powders (SLPs) by gas chromatography–mass spectrometry (GC-MS): a systematic investigation into injector conditions and their effect on the characterisation of samples

Smokeless powders (SLPs) are composed of a combination of thermolabile and non-thermolabile compounds. When analysed by GC-MS, injection conditions may therefore play a fundamental role on the characterisation of forensic samples. However, no systematic investigations have ever been carried out. This casts doubt on the optimal conditions that should be adopted in advanced profiling applications (e.g. class attribution and source association), especially when a traditional split/splitless (S/SL) injector is used. Herein, a study is reported that specifically focused on the evaluation of the liner type (Ltype) and inlet temperature (Tinj). Results showed that both could affect the exhaustiveness and repeatability of the observed chemical profiles, with Ltype being particularly sensitive despite typically not being clarified in published works. Perhaps as expected, degradation effects were observed for the most thermolabile compounds (e.g. nitroglycerin) at conditions maximising the heat transfer rates (Ltype = packed and Tinj ≥ 200 °C). However, these did not seem to be as influential as, perhaps, suggested in previous studies. Indeed, the harshest injection conditions in terms of heat transfer rate (Ltype = packed and Tinj = 260 °C) were found to lead to better performances (including better overall %RSDs and LODs) compared to the mildest ones. This suggested that implementing conditions minimising heat-induced breakdowns during injection was not necessarily a good strategy for comparison purposes. The reported findings represent a concrete step forward in the field, providing a robust body of data for the development of the next generation of SLP profiling methods.Graphical abstract

Survey of Liner Characteristics Used in Japan

Highlights The vacuum during milking causes teat ends to suck into liners by 7 to 10 cm. Liner rubber is classified as hard or soft. Volume changes are greater in round liners than those of other shapes in the pulsation cycle. Non-round liners did not press completely during the closing phase. The liner shape had a greater effect on liner volume change than the material. ABSTRACT. A variety of liner shapes are used in the dairy industry in Japan, and it is not known which is optimal for maintaining teat-end condition, preventing mastitis, ensuring milk quality, and improving dairy cow and milking system performance. Liners can be generally classified into types based on their internal shape: round, round with ribs on the outside of the liner, triangular, clover-shaped, or square. In addition, liners can be characterized based on the position of the air vent. The optimal combination of air vent location and internal shape for the maintenance of good teat end condition has not been clarified. The aim of this study is to survey liners in Japan to determine the characteristics of liners currently in use. The depth to which the teat end is pulled into the liner during milking was investigated. An experimental vacuum device was fabricated to measure the touch-point and closure-point (the vacuum levels at which the opposite sides of the internal liner surface begin to touch, and the level at which the liner bore completely closes, respectively). In addition, the volume change of the pulsation chamber during the pulsator opening and closing phases was also investigated. The internal shape of the liner was molded when the liner was opened and closed, and the cross-sectional area was compared for each liner type. The findings showed that liner hardness could be characterized as being either soft or hard. The change in the borevolume of round liners during a pulsation cycle, i.e., between the pulsation opening phase and the closing phase, was larger than that observed with the other liners. The cross-sectional area of the molded shape tended to be wider for liners of other shapes than for round liners. This study investigated and compared the characteristics of various types of liners and found that the characteristics varied widely. It is not clear what kind of liner shape is best, and further research is needed. Keywords: Liner internal shape, Overpressure, Pulsation, Teat end condition, Teat end position.