Understanding the Relationship between Vaccine Supply Dead Space and Wasted COVID-19 Vaccine Doses.

INTRODUCTION: By July 2023, Brazil had administered approximately 540 million COVID-19 vaccine doses. This study aimed to quantify wasted doses resulting from dead space in vaccine supplies. METHODS: The vaccine supply was initially weighed, filled with distilled water, and expelled to simulate administration. Weighing it again after the application determined the dead space volume. Descriptive analyses calculated the waste rate/wasted dose count. RESULTS: The estimated total number of wasted vaccine doses using supplies with the lowest dead space was 62,097,338. CONCLUSIONS: Syringe dead space is a crucial factor in dose wastage, directly influencing the number of wasted doses.

Adaptation and clinical application of assistive device chair for bedside sitting in acute stroke phase: two case reports.

PURPOSE: This report presents the adaptation of an assistive device chair for bedside sitting and its application in two patients with trunk control impairment in the acute stroke phase. MATERIALS AND METHODS: The device was built with polyvinylchloride (PVC) pipes and designed by a team of mechanical engineers and physiotherapists to maintain a prolonged sitting position with less demand from therapists. To test the device, two patients were followed up during the acute phase of stroke. Both patients underwent an early mobilization program (30 min, twice a day, for three days) with an assistive device chair for bedside sitting. Patients were evaluated using the National Institutes of Health Stroke Scale (NIHSS), Trunk Impairment Scale (TIS), and International Classification of Functioning, Disability, and Health (ICF) checklist (b: body function; d: activity and participation). RESULTS: The adaptations generated the following equipment: 1) foldable, 2) three levels of backrest inclination, and 3) a safety anterior support or an activity table. Both patients showed clinical improvement after the intervention period, with NIHSS score reduction, TIS improvement, and greater functionality and independence on the ICF framework. CONCLUSION: The equipment with adaptations seems to be functional, easy to handle, and can potentially contribute to clinical and functional improvements in patients with trunk control deficits after stroke.

The assistive device chair has a low manufacturing cost, and allow an easy handling and storageThe assistive device chair has been adapted to facilitate sitting posture;The assistive device chair can be used as an auxiliary tool in early mobilizations protocols and contemporary rehabilitation approaches;The early mobilization protocol associated with the assistive device chair can generate clinical improvements in acute stroke.The mobilization protocol associated with the assistive device chair can promote improvement in International Classification of Functioning, Disability, and Health domains in acute stroke.

Understanding the Relationship between Vaccine Supply Dead Space and Wasted COVID-19 Vaccine Doses

ABSTRACT Introduction: By July 2023, Brazil had administered approximately 540 million COVID-19 vaccine doses. This study aimed to quantify wasted doses resulting from dead space in vaccine supplies. Methods: The vaccine supply was initially weighed, filled with distilled water, and expelled to simulate administration. Weighing it again after the application determined the dead space volume. Descriptive analyses calculated the waste rate/wasted dose count. Results: The estimated total number of wasted vaccine doses using supplies with the lowest dead space was 62,097,338. Conclusions: Syringe dead space is a crucial factor in dose wastage, directly influencing the number of wasted doses.

Chitosan-based mucoadhesive gel for oral mucosal toluidine blue O delivery: The influence of a non-ionic surfactant.

Photodynamic therapy (PDT) has been successfully employed in the treatment of oral cancer. Toluidine blue O (TBO) is a photosensitizer (PS) that has exhibited remarkable photocytotoxicity in a variety of tumour cells; however, its physicochemical properties, as well as the physicochemical properties of oral mucosa, prevent the drug from reaching the target site at a therapeutic concentration. The aim of this study was to evaluate the influence of Tween 80® (TW), which has shown potential as a penetration enhancer, on the mucosal retention of TBO for the PDT of oral cancer. 4% Chitosan-based mucoadhesive gels (CH gels) containing or not 5%TW were prepared (both containing 1%TBO), and their physicochemical properties (pH, rheology and mucoadhesion), TBO in vitro release profiles and TBO in vitro mucosal retention were evaluated. In vivo mucosal penetration studies of TBO followed by laser exposition were also carried out. The results showed that 4%CH gels containing 5%TW and 1%TBO have adequate mucoadhesive and rheological properties for oral mucosa use, although they present a slightly acid pH. TBO release studies showed that TW reduces TBO release, but it prolongs TBO release and increases TBO retention in the mucosa. In vivo studies showed that 4%CH gels containing 5%TW and 1%TBO cause an increase in the number of apoptotic cell, after laser exposition. In summary, 4%CH gels containing 5%TW may be a promising vehicle to optimize the penetration of TBO in oral mucosa and to improve the PDT response for the treatment of oral cancer.

Improving adhesion between luting cement and zirconia-based ceramic with an alternative surface treatment.

This study evaluated the influence of an alternative surface treatment on the microshear bond strength (µsbs) of zirconia-based ceramic. Thirty-five zirconia disks were assigned to five groups according to the following treatments: Control (CO), glass and silane were not applied to the zirconia surface; G1, air blasted with 100µm glass beads + glaze + silane; G2, a gel containing 15% (by weight) glass beads applied to the ceramic surface + glaze + silane; G3, a gel containing 25% (by weight) glass beads applied to the ceramic surface + glaze + silane; and G4, a gel containing 50% (by weight) glass beads applied to the ceramic surface + glaze + silane. The specimens were built up using RelyX ARC®, according to the manufacturer's recommendations, and inserted in an elastomeric mold with an inner diameter of 0.8 mm. The µsbs test was performed using a testing machine at a crosshead speed of 0.5 mm/min. ANOVA and Tukey's test (p < 0.05) were applied to the bond strength values (in MPa). CO (15.6 ± 4.1) showed the lowest µsbs value. There were no statistical differences between the G1 (24.9 ± 7.4), G2 (24.9 ± 2.3), G3 (35.0 ± 10.3) and G4 (35.3 ± 6.0) experimental groups. Those groups submitted to surface treatments with higher concentrations of glass showed a lower frequency of adhesive failures. In conclusion, the glass application improved the interaction between the ceramic and the luting cement.

Evaluation of shoulder overload during acrobatic flight: Analysis of pilot's self-report and surface electromyography (SEMG).

BACKGROUND AND OBJECTIVES: The physical injuries caused by +Gz include skeletal-muscle overloads. This study has aimed at demonstrating ergonomic conditions of the pilots from the Brazilian Air Force's Aerial Demonstration Squadron (BAFADS) during flight. METHODS: All the 13 pilots from the BAFADS were evaluated through an interview. Surface electromyography (SEMG) was employed during the flight manoeuvre simulation (under normal and overload conditions). RESULTS: The report analyses showed perception of discomfort in the right shoulder related to +Gz. The SEMG showed moderate levels of shoulder muscles activation for normal contractions (± 25%). During vigorous contraction, levels of recruitment were high: upper trapezius fibres (± 105%), middle trapezius fibres (± 90%) and posterior deltoid fibres (± 95%). The great demand from the deltoid muscles (posterior fibres) infers a very high level of recruitment from the rotator cuff muscle, which may explain the discomfort in the pilots' shoulder during the flight manoeuvre. CONCLUSION: The mutual analysis of both methods not only does it demonstrate a correlation between symptoms and muscle recruitment, but also provides data to implement intervention measures for pilots' physical training in order to minimise the discomfort symptoms during flights.

Using chitosan gels as a toluidine blue O delivery system for photodynamic therapy of buccal cancer: In vitro and in vivo studies.

BACKGROUND: Photodynamic therapy (PDT) is an emerging treatment that has demonstrated potential for the clinical treatment of buccal cancer. It is based on the photoactivation of a photosensitizer (PS) when irradiated by light at a specific wavelength. The light-excited PS generates reactive oxygen species that cause the destruction of tumor cells by apoptosis or necrosis. Toluidine Blue O (TBO) is a PS that has shown potential for PDT in cancer treatment. However, saliva and mechanical activities quickly remove the PS from the surface of the buccal mucosa. Therefore, the bioavailability of PS at the surface of target tissues is reduced. The aim of this study was to evaluate the potential of chitosan (CH) gels in TBO delivery to buccal tissue. METHODS: CH gels were obtained at different concentrations and their physico-chemical properties (pH and rheology), mucoadhesion, in vitro release profile, in vivo retention and in vivo efficacy by the ability to induce cell apoptosis were evaluated. RESULTS: CH-based mucoadhesive gels optimized the release and adherence of preparations at the target site. Specifically, 4% (w/w) CH gel showed adequate properties for buccal use, such as pH value, mucoadhesion, pseudoplastic behavior, extended release, minimal permeation and higher TBO retention by the mucosa. In vivo studies showed the potential of the gel to enhance TBO retention and induce cell apoptosis after laser irradiation. CONCLUSION: 4% (w/w) CH based mucoadhesive gel can be explored as a TBO delivery system in the PDT of oral cancer.

Improving adhesion between luting cement and zirconia-based ceramic with an alternative surface treatment

This study evaluated the influence of an alternative surface treatment on the microshear bond strength (μsbs) of zirconia-based ceramic. Thirty-five zirconia disks were assigned to five groups according to the following treatments: Control (CO), glass and silane were not applied to the zirconia surface; G1, air blasted with 100μm glass beads + glaze + silane; G2, a gel containing 15% (by weight) glass beads applied to the ceramic surface + glaze + silane; G3, a gel containing 25% (by weight) glass beads applied to the ceramic surface + glaze + silane; and G4, a gel containing 50% (by weight) glass beads applied to the ceramic surface + glaze + silane. The specimens were built up using RelyX ARC®, according to the manufacturer’s recommendations, and inserted in an elastomeric mold with an inner diameter of 0.8 mm. The μsbs test was performed using a testing machine at a crosshead speed of 0.5 mm/min. ANOVA and Tukey’s test (p < 0.05) were applied to the bond strength values (in MPa). CO (15.6 ± 4.1) showed the lowest μsbs value. There were no statistical differences between the G1 (24.9 ± 7.4), G2 (24.9 ± 2.3), G3 (35.0 ± 10.3) and G4 (35.3 ± 6.0) experimental groups. Those groups submitted to surface treatments with higher concentrations of glass showed a lower frequency of adhesive failures. In conclusion, the glass application improved the interaction between the ceramic and the luting cement.

Analysis of stress induced by screws in the vertebral fixation system.

OBJECTIVE: To compare, using photoelasticity, internal stress produced by USS II type screw with 5.2 and 6.2 mm external diameters, when submitted to three different pullout strengths. METHODS: Two photoelastic models were especially made. The simulation was performed using loads of 1.8, 2.4 e 3.3 kgf.The fringe orders were evaluated around the screws. In all the models analyzed the shear stress were calculated. RESULTS: Independently of the applied load, the smaller screw showed higher values of shear stress. CONCLUSION: According to the analysis performed, we observed that the place of highest stress was in the first thread of the lead, close to the head of the screws. Experimental study.

Analysis of stress induced by screws in the vertebral fixation system

Objective: To compare, using photoelasticity, internal stress produced by USS II type screw with 5.2 and 6.2 mm external diameters, when submitted to three different pullout strengths. Methods: Two photoelastic models were especially made. The simulation was performed using loads of 1.8, 2.4 e 3.3 kgf.The fringe orders were evaluated around the screws. In all the models analyzed the shear stress were calculated. Results: Independently of the applied load, the smaller screw showed higher values of shear stress. Conclusion: According to the analysis performed, we observed that the place of highest stress was in the first thread of the lead, close to the head of the screws. Experimental study. .

Photoelastic analisys in the lower region of vertebral body L4.

OBJECTIVE: To analyze the shear forces on the vertebral body L4 when submitted to a compression force by means of transmission photoelasticity. METHODS: Twelve photoelastic models were divided into three groups, with four models per group, according to the positioning of the sagittal section vertebrae L4-L5 (sections A, B and C). The simulation was performed using a 15N compression force, and the fringe orders were evaluated in the vertebral body L4 by the Tardy compensation method. RESULTS: Photoelastic analysis showed, in general, a homogeneous distribution in the vertebral bodies. The shear forces were higher in section C than B, and higher in B than A. CONCLUSION: The posterior area of L4, mainly in section C, showed higher shear concentrations, corresponding to a more susceptible area for bone fracture and spondylolisthesis. Economic and Decision Analyses - Development of an Economic or Decision Model. Level I.

Análise fotoelástica da região inferior do corpo vertebral L4 / Photoelastic analisys in the lower region of vertebral body L4

OBJETIVO: Analisar as tensões geradas no corpo vertebral L4 quando submetida à força de compressão, utilizando a técnica da fotoelasticidade de transmissão. MÉTODOS: Doze modelos fotoelásticos foram utilizados e divididos em três grupos, sendo cada grupo formado por quatro modelos, de acordo com a localização do corte sagital nas vértebras L4-L5 (cortes A, B e C). A simulação foi realizada utilizando uma força compressão de 15 N e as ordens de franjas foram avaliadas no corpo vertebral L4 utilizando o método de compensação de Tardy. RESULTADOS: A análise fotoelástica mostrou que em geral, as tensões se distribuíram de forma homogênea nos corpos vertebrais. As tensões no corte C foram maiores que no B, que por sua vez foram maiores que no corte A. CONCLUSÃO: A região posterior do corpo vertebral L4, principalmente no corte C, apresentou maiores concentrações de tensões, sendo assim, é a área mais susceptível à fratura vertebral e à espondilolistese. Análises econômicas e de decisão. Desenvolvimento de modelo econômico ou de decisão, Nível de evidência I.

OBJECTIVE: to analyze the shear forces on the vertebral body L4 when submitted to a compression force by means of transmission photoelasticity. METHODS: Twelve photoelastic models were divided into three groups, with four models per group, according to the positioning of the sagittal section vertebrae L4-L5 (sections A, B and C). The simulation was performed using a 15N compression force, and the fringe orders were evaluated in the vertebral body L4 by the Tardy compensation method. RESULTS: Photoelastic analysis showed, in general, a homogeneous distribution in the vertebral bodies. The shear forces were higher in section C than B, and higher in B than A. CONCLUSION: The posterior area of L4, mainly in section C, showed higher shear concentrations, corresponding to a more susceptible area for bone fracture and spondylolisthesis. Economic and Decision Analyses - Development of an Economic or Decision Model. Level I.

Influence of ceramic primers on microshear bond strength between resin cements and zirconia-based ceramic

This study evaluated the effect of a coupling agent ceramic primer (CP) on the microshear bond strength (ìsbs) between luting cements and zirconia-based ceramic. Methods: Zirconia discs (Cercon) were made and finished with silicon carbide paper and submitted to air abrasion using 50 μm aluminum oxide particles (Al2O3) under 4 bar pressure. Zirconia disks were randomly assigned to four groups (n=10): (G1) ResiCem luting cement + Porcelain Primer, (G2) ResiCemluting cement only, (G3) Clearfil Esthetic Cement + Clearfil Ceramic Primer and (G4) Clearfil Esthetic Cement only. The luting cements were prepared according to manufacturers’ recommendations and inserted in an elastomeric mold positioned onto a zirconia disc. Each specimen was photoactivated by 20 s. The specimens were stored at 100% relative humidity and 37ºC for 24 h. The ìsbs test was performed using universal testing machine at a crosshead speed of 0.5 mm/min. An optical microscope was used to analyze the failure modes and illustrative images were captured with a scanning electron microscope. The ìsbs data were analyzed by two-way ANOVA (p<0.05). Results: No significant difference was found among the four groups G1 (17.4±6.8), G2 (17.1±5.5), G3 (15.6±5.5) and G4 (14.2±3.5), all of which showed 100% of adhesive failures. Conclusions: CP showed no increase in the ìsbs between zirconia-based ceramic and resin luting cements.

Tension band wire fixation for valgus osteotomies of the proximal femur: a biomechanical study of three configurations of fixation.

BACKGROUND: A variety of techniques can be used to achieve stabilization of femoral valgus osteotomies in children, but what is lacking is a versatile fixation system that associates stability and versatility at different ages and for different degrees of deformity. METHODS: Mechanical tests of three configurations used to fix femoral valgus osteotomies, based on the tension band wire principle, were carried out. A 30 degrees wedge valgus osteotomy was performed at the subtrochanteric level in 60 swine femurs and fixed with three different systems. In Group 1, two Kirschner wires (K wire) were introduced from the tip of the greater trochanter to the medial cortex, crossing the osteotomy. A flexible steel wire was anchored to the K wires into holes in the lateral cortex and tightened to form a tension band. The same setup was used in Group 2, but two additional smooth K wires were inserted into the lateral surface of the greater trochanter and driven to the femoral head with the distal extremities bent and tied around the bone shaft. In Group 3, the fixation was similar to that in Group 2, but the ascending K wires were introduced below the osteotomy level, crossing the osteotomy. Mechanical tests in bending-compression and torsion were used to access the stability. FINDINGS: The torsional relative stiffness was 116% greater for Group 3 (0.27 Nm/degree) and no significant difference was found between Group 1 (0.10Nm/degree) and Group 2 (0.12 Nm/degree). The average torque was 103% higher for Group 3 (1.86 Nm). Stiffness in bending-compression was significantly higher in Group 3 (508 x 10(3) N/m) than in Group 1 (211 x 10(3) N/m) and Group 2 (219 x 10(3) N/m). INTERPRETATION: Fixation as used in Group 3 was significantly more stable, both in torsion and bending-compression tests, than the other two techniques.

Comportamento mecânico do terço proximal de fêmures de ratos após período de suspensão pela cauda e exercitação / Mechanical behavior of rats' femoral proximal thirds after a period of tail suspension and exercises

A remodelação óssea pode ser estimulada por forças mecânicas presentes nas atividades físicas normais. Neste trabalho foi analisado o comportamento mecânico do terço proximal de fêmur de ratas submetidas à suspensão pela cauda e posterior treinamento em esteira. Sessenta e seis ratas da raça Wistar foram usadas. Primeiramente os animais foram criados por noventa dias e divididos em cinco grupos (dois controles e três experimentais). Os animais do grupo Controle I foram sacrificados com 118 dias de idade. No grupo S (suspenso) os animais foram suspensos pela cauda por 28 dias e sacrificados. No grupo Controle II os animais foram sacrificados com 139 dias de idade. No grupo S-L (suspenso-liberado) as ratas foram liberadas 21 dias após a suspensão. No grupo S-T (suspenso-treinado) após o período de suspensão os animais passaram por treinamento em esteira durante 21 dias. Para análise do comportamento mecânico do osso foi aplicada uma força vertical na cabeça femoral até a ruptura. A fratura foi analisada por raios-X. A suspensão causou um decréscimo da força máxima e, o treinamento e a liberação após a suspensão causaram a recuperação das propriedades mecânicas. Mas, o padrão de fratura não apresentou diferença entre os grupos experimentais.

Bone remodeling can be stimulated by mechanical forces present in normal physical activities. In the present research, we investigated the mechanical behavior of the proximal femur of rats previously maintained in tail suspension and later, submitted to physical exercise on a treadmill. Sixty-six Wistar rats were used. Firstly, the animals were raised until the age of ninety days and then divided into five groups (two control groups and three experimental groups). The animals allocated to Control I group were killed at 118 days of age. In the S group, the animals were suspended by tail for 28 days. In Control II group, the animals were killed at 139 days of age. In group S-L (suspended and released) the rats were kept free for 21 days after tail suspension. In group S-T (suspended and trained), after tail suspension period, the rats were trained in a treadmill for 21 days. For analysis of the mechanical behavior of the bone, force was applied on the femoral head until failure. The fracture was evaluated by x-ray. Suspension caused a decrease of the maximum load and, treadmill training and post-suspension release caused the recovery of mechanical properties. But, the fracture line pattern did not show any difference among the experimental groups.