Desired Activity Level Research Articles

Creation of Money in a Full Reserve Banking System and the Separation of Money from Interest – Presentation of the Balance Sheets of the Central Bank and Commercial Banks in Bosnia and Herzegovina

This paper evaluates the impact of a paradigm shift in the monetary system by introducing a model of full reserve banking, focusing on the outcome of separating the generation of money from interest, which can only be achieved by abolishing the system of creating money through debt creation in the banking system. The main thesis argues that the current system, in which private commercial banks create money by issuing loans, results in deposits that mix savings achieved through economic activity with newly created money, leading to economic inefficiency and potential instability because debt and interest are always greater than the economic value created. The 100% sovereign money system corrects this by ensuring that only the central bank has the authority to create money, simplifying the financial landscape and restoring money to its rightful status as a public good and stable unit of measure. The study uses a comparative analysis between the current banking system with fractional reserves and the proposed banking system with 100% sovereign money, which is entirely reserve money. Balance sheet modeling demonstrates the impact of segregating investment and deposit accounts on the books of banks and the central bank. The methodology includes a hypothetical presentation of the balance sheet under the new system, emphasizing the accounting separation of “deposit” and “investment” accounts to end the creation of money by private commercial banks. The balance sheet analysis indicates that adopting a 100% sovereign money system requires state intervention through state deposits into the banking system to achieve the desired level of credit activity.

Optimizing Health-Related Outcomes Following Musculoskeletal Injury Through the Integration of Self-Efficacy Theory and the Fear Avoidance Model

A primary goal of rehabilitation is to produce optimal health-related quality of life outcomes, which includes returning patients to their desired level of activity. Injury-related fear, kinesiophobia, and fear-avoidance beliefs are psychological factors that negatively impact health-related quality of life and are associated with decreased levels of physical activity. Conversely, increased levels of self-efficacy have been linked to favorable rehabilitation outcomes. To promote full recovery and optimal health-related quality of life, the rehabilitation process should consider addressing self-efficacy and injury-related fear (e.g., kinesiophobia, fear-avoidance beliefs). Therefore, the purpose of this paper is to introduce a theoretical framework which integrates self-efficacy theory and the Fear-Avoidance Model to mitigate injury-related fear and optimize patient outcomes following musculoskeletal injury. The intention of this theoretical framework is to provide clinicians with psychosocial interventions to improve self-efficacy and prevent the progression of injury-related fear at varying times throughout the rehabilitation process.

Dynamic joint stiffness in individuals with femoroacetabular impingement syndrome pre- and post-hip arthroscopy

BackgroundPatients with hip-related pain often fail to return to their desired level of activity following hip arthroscopy. Lasting biomechanics alterations may be one potential explanation. Dynamic joint stiffness assesses the mechanistic controls of the lower limb during high impact movements, and thus, may provide valuable clinical targets to improving movement and optimizing return to activity after surgery. MethodsTwenty-five participants (13 females) with hip-related pain underwent 3D motion capture during a drop jump task before surgery and six months post-operatively. Nineteen healthy controls (9 females) were collected for comparison. Sagittal plane dynamic joint stiffness was calculated during the initial landing phase. Baseline and 6-month dynamic joint stiffness data were compared 1) between males and females with hip-related pain and 2) between individuals with hip-related pain and controls using Wilcoxon Signed-Rank and Mann Whitney U tests. Sexes were analyzed separately. FindingsFrom baseline to 6 months post-operatively, females with hip-related pain demonstrated decreased dynamic ankle stiffness (2.26 Nm/deg. [0.61] to 1.84 Nm/deg. [0.43]) (p = .005) and males with hip-related pain demonstrated increased dynamic hip stiffness (2.73 [0.90] to 3.88 [1.73]) (p = .013). There were no differences in dynamic stiffness at any joint between individuals with hip-related pain at either timepoint when compared to controls (p ≥ .099). InterpretationFemales and males with hip-related pain may demonstrate unique changes in dynamic joint stiffness after surgery, indicating return to activity may follow different trajectories for each sex. Additional work should examine the relationship between hip joint stiffness and treatment outcomes and identify additional movement-related rehabilitation targets.

Open Hamstring Tendon Excision Following a Distal Semitendinosus Avulsion Tear: A Technique Video

Background: Hamstring injuries are commonly considered the number one reason for delayed return to play and return to sport (RTS) across several sport disciplines. Traditionally, they are treated conservatively. However, recent literature has shown surgical intervention to improve recovery and expedite RTS. One potential explanation behind this phenomenon is conservative treatment does not address the disrupted length-tendon relationship, which can cause hamstring re-injury. Indications: Operative indications for tendon excision include patients with distal semitendinosus avulsions tear with retraction, especially patients who had already failed conservative management. Elite athletes with distal hamstring tears who have experienced a delayed RTS or desired activity level should also be considered for distal hamstring excision. Technique Description: A distal 4-cm incision, which was longitudinal in line with the semitendinosus, was made over the posterior knee at the measured level of the avulsed tendon stump, 2 cm proximal to the knee flexion crease. Blunt dissection was used for the subcutaneous layers, and the overlying hypertrophic and fibrotic tendon sheath was sharply incised. The torn and retracted tendon tissue was exteriorized. An allis clamp was used to provide tension on the distal semitendinosus, and mobilization of the avulsed tendon was performed. Sheath tissue surrounding the injured tendon was removed. The stump was whipstitched to provide further traction, and the hypertrophied portion of the tendon was excised. An open tendon stripper was implemented to exercise both limbs of the semitendinosus. The subcutaneous tissue and skin were closed, and an incisional wound vac was placed. Discussion/Conclusion: Distal avulsion tears of semitendinosus tendons can lead to unsatisfactory results with conservative treatment, with delayed RTS and recurrence of symptoms. Resection of hamstring tendon tissue may eliminate the recurrence of injury, along with inflammation, fibrosis, and hemorrhage associated with retraction reinjuries. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

A Pilot Study Conducted at a Tertiary Cancer Care Center, Evaluating the Serum Asparaginase Activity in Children Suffering from Acute Lymphoblastic Leukemia after the Administration of Biosimilar Pegaspargase

Abstract Introduction L-asparaginase is considered to be the most important component in the treatment of acute lymphoblastic leukemia (ALL). Intensifying the use of L-asparaginase during treatment for ALL has resulted in a significant rise in the percentage of children and adolescents who are cured of the disease. Asparaginase trough activity more than or equal to 100 IU/L on day 7 has been found to be the desired activity level in all childhood leukemia patients. Objectives Due to the paucity of data on biosimilar pegaspargase in the upfront setting, we planned this prospective pilot study to evaluate the levels of serum asparaginase activity (SAA) after biosimilar pegaspargase infusion. Materials and Methods It is a prospective, single-center, pilot study of 10 pediatric ALL patients for the duration of 6 months. All children less than 18 years with ALL on treatment with curative intent and receiving pegaspargase and who provided informed consent were included in this study. The enzymatic spectrophotometric method was used to determine SAA, and it was measured on the 7th and 14th days after the first dosage of pegaspargase-asparaginase, as well as on the 14th day after the second dose of pegaspargase-asparaginase, while toxicity was charted according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Results From 10 patients with a median age of 5.5 years, a grand total of 29 samples were taken for analysis. Children who received pegaspargase had either B-ALL or T-ALL. After the first dose, mean ± SD (standard deviation), SAA levels at day 7 was 131.3 ± 38 IU/L and at Day 14 was 94.8 ± 8 IU/L. After the second dose, mean ± SD SAA level at day 14 was 86.1 ± 15 IU/L. No patient had clinical hypersensitivity reaction and no patient reported any asparaginase-related toxicity. One patient died due to sepsis, infection with multidrug-resistant gram-negative bacteria. Conclusions Biosimilar pegaspargase maintained good SAA levels 7 and 14 days after infusion. Drug Trial Registration: Clinical Trial Registry of India vide reference CTRI/2021/08/036033 and available at https://ctri.nic.in/Clinicaltrials/pmaindet2.php?trialid=59285&EncHid=&userName=

Tarsal coalition resections: a long-term retrospective analysis of 97 resections in 78 patients

BackgroundResection of tarsal coalitions provides good patient satisfaction scores, reduced pain, and improved long-term function in both athletic and non-athletic populations. This study aimed to determine when athletic patients undergoing resection of a tarsal coalition were able to return to their desired activity, and whether they experienced a decreased desired activity level (DDA).MethodsData on a total of 78 patients who underwent 97 tarsal coalition resections (49 talocalcaneal coalitions, 47 calcaneo-navicular, 14 cuboid-navicular, and three cuneo-navicular; some patients had more than one coalition) operated between January 2001 and June 2020 were prospectively collected. To subjectively assess outcomes, the Roles and Maudsley score (RM) was utilized.ResultsAt an average follow-up from the index procedure of 33.6 ± 41.5 months, return to activity for the entire cohort was 18.3 ± 9.6 weeks. Post-RM was 1.3 ± 0.6.ConclusionSurgical excision of tarsal coalitions produced favorable results, with most patients able to return to their desired activity level.Level of evidenceIV.

Estimating technology characteristics of the U.S. hospital industry using directional distance functions with optimal directions

The use of the directional distance function (DDF) in empirical studies has steadily increased over the past decade due to its general representation of a production technology. The DDF is particularly useful in health economics as a tool for modeling the hospital technology. Choosing the direction when modeling technology with the DDF is a crucial, albeit not fully resolved, issue that has important ramifications. We first address the choice of direction by using a recently proposed approach for endogenizing the DDF’s direction vector and then extend it by imposing regularity conditions on the technology. We apply this framework to a sample of U.S. hospitals and obtain their technology characteristics after grouping them into several distinct categories. We find that publicly owned non-teaching hospitals face substantial opportunity costs of inpatient care – hundreds of outpatient visits must be forgone for each additional admission. This information can help these hospitals forecast the adjustment in outpatient capacity needed to achieve a desired level of inpatient activity. We also find that while urban-area teaching hospitals can substitute approximately two nurses per bed at the frontier of technology, the rate of substitution is less than one nurse per bed at public non-teaching hospitals as well as at all rural-area hospitals. Information on the technological trade off between beds and nurses is helpful to hospital administrators and policy makers as nursing shortages intensify and staffing requirements continue to be debated. In addition, we demonstrate that rural public hospitals, which heavily rely on licensed practical nurses (LPNs) to staff their beds, are the only hospitals that can meaningfully substitute LPNs for the other inputs, replacing each bed and each registered nurse with medians of 17 and 23 LPNs, respectively.

Comparison of Calcaneal Subchondral Injection of Calcium Phosphate and Plantar Fasciotomy vs Plantar Fasciotomy Alone for Refractory Infracalcaneal Heel Pain.

Background:Treatment of chronic refractory heel pain has evolved to consider calcaneal structural fatigue as a component of the symptom profile. While concomitant calcium phosphate injection has become a method of addressing the accompanying calcaneal bone marrow edema (BME) frequently seen in this population, there is no literature supporting its use compared to traditional fasciotomy.Methods:Consecutive patients with symptoms of refractory infracalcaneal heel pain and calcaneal BME were treated in our practice by either surgical fasciotomy (n = 33) or fasciotomy plus calcium phosphate injection (n = 31) between 2014 and 2019. Outcomes were retrospectively assessed via Foot and Ankle Outcome Scores (FAOS), return to activity, and complication rate.Results:Sixty-four patients (64 feet) were included with a mean age of 50.3 ± 12.9 years and mean follow-up of 23.2 ± 22.3 months. No differences were observed between groups preoperatively. Significant improvements in 4 of 5 FAOS subscales were observed postoperatively in both groups (P < .05 for all, paired t test). However, patients undergoing concomitant calcium phosphate injection reported significantly better scores for both activities of daily living (ADL; mean difference +10.2; 95% confidence interval [CI] 0.07-20.2) and foot-specific QOL (mean difference +21.9, 95% CI 7.0-36.6) at final follow-up compared with those undergoing plantar fasciotomy alone. All patients returned to their desired level of activity, and the frequency of complications did not differ between groups (P > .05, Fisher exact test).Conclusion:In patients presenting with recalcitrant infracalcaneal heel pain accompanied by calcaneal BME, calcium phosphate injection into the calcaneus, when combined with plantar fasciotomy, was safe and more effective than traditional plantar fasciotomy alone.Level of Evidence:Level III, retrospective comparative study.

Trajectories of Recovery after Atrial Fibrillation Ablation.

Ablation procedures are common for patients with atrial fibrillation (AF), yet evidence is limited about patient perceptions of their recovery following ablation. We sought to expand understanding of this recovery process. Twenty participants undergoing their first AF ablation completed semi-structured interviews prior to ablation (baseline) and at one, three, and six months post AF ablation. Pre-procedure education is modeled after education used for other ablation procedures, preparing patients to expect a single recovery trajectory. We identified two recovery trajectories that varied in speed of symptom resolution: sustained improvement and pseudo improvement. Recovery was slower than expected in both trajectories. Moreover, returning to desired activity levels consistently lagged behind other symptom resolution by approximately two months. A more accurate understanding of what patients experience post-ablation, as illustrated in these findings, serves as a beginning step to alter patient education prior to AF ablation to better prepare individuals for the recovery process.

The effectiveness of PROLOTHERAPY for recalcitrant Medial TIBIAL Stress Syndrome: a prospective consecutive CASE series

BackgroundMedial tibial stress syndrome (MTSS) is one of the most common lower leg injuries in sporting populations. It accounts for between 6 and 16% of all running injuries, and up to 53% of lower leg injuries in military recruits. Various treatment modalities are available with varying degrees of success. In recalcitrant cases, surgery is often the only option.ObjectiveTo evaluate whether ultrasound-guided injection of 15% dextrose for treatment of recalcitrant MTSS decreases pain and facilitates a return to desired activity levels for those who may otherwise be considering surgery or giving up the sport.MethodThe study design was a prospective consecutive case series involving eighteen patients: fifteen male and three female; (mean age = 31.2 years) with recalcitrant MTSS. They were referred from sports injury clinics across the UK, having failed all available conservative treatment.InterventionAn ultrasound-guided sub-periosteal injection of 15% dextrose was administered by the same clinician (NP) along the length of the symptomatic area. Typically, 1 mL of solution was injected per cm of the symptomatic area.Main outcome measuresPain was assessed using a 10-cm visual analog scale (VAS) at baseline, short-term, medium-term (mean 18 weeks), and long-term (mean 52 weeks) follow-up. Symptom resolution and return to activity were measured using a Likert scale at medium and long-term follow-up. Statistical analyses were performed using SPSS for Mac version 19.0.0 (IBM, New York, NY, US). The Shapiro-Wilk test was used to evaluate the normality of the distribution of data. Friedman’s non-parametric test was used to compare the within-patient treatment response over time. Post-hoc Wilcoxon signed-rank tests with Bonferroni corrections were performed to determine VAS average pain response to treatment over five paired periods.ResultsPatients reported a significant (p < 0.01) reduction in median VAS pain score at medium and long-term follow-up compared to baseline. Median improvement per patient was 4.5/10. Patients rated their condition as ‘much improved’ at medium-term follow-up and the median return to sports score was ‘returned to desired but not pre-injury level’ at medium-term and long-term follow-up. No adverse events were reported.ConclusionsUltrasound-guided 15% dextrose prolotherapy injection has a significant medium-term effect on pain in MTSS. This benefit may be maintained long-term; however, more robust trials are required to validate these findings in the absence of controls.Clinical relevanceClinicians should consider the use of ultrasound-guided injection of 15% dextrose as a viable treatment option to reduce pain and aid return to activity for patients with recalcitrant MTSS.

Results of an Accelerated Rehabilitation Program after Arthroscopic Broström Ankle Ligament Repair Augmented with an Arthroscopically Applied Suture Tape

Category:Arthroscopy; Ankle; SportsIntroduction/Purpose:The Broström-Gould is the gold standard in repair of the lateral ankle ligaments for chronic instability and arthroscopic Broström repairs have become increasingly popular with outcomes comparable to the open procedure. Despite demonstrated success, the arthroscopic Broström, like the open procedure, does not achieve the same mechanical strength as the intact native ankle ligaments and is therefore not appropriate for early aggressive rehabilitation. Suture tape augmentation of an open Broström procedure has been shown to further strengthen the repair and produce favorable outcomes in preventing recurrent instability. Studies reporting long-term clinical outcomes of patients who undergo this procedure are lacking. This study reports clinical and functional outcomes after an arthroscopic repair with arthroscopically applied suture tape augmentation and an accelerated post-operative rehabilitation protocol.Methods:Ninety-three patients with chronic recurrent ankle instability who had failed non-operative treatment (bracing, taping, physical therapy) underwent arthroscopic lateral ligament repair augmented by a suture tape applied in a novel all-arthroscopic fashion (double stranded polyethylene tape fixed to talus and fibula with interference screws). Postoperatively patients were placed in a CAM walker and allowed to bear weight immediately. On postoperative day 8 patients were placed in a functional brace and began physical therapy to include motion, strength, and proprioceptive activities. At week 4 patients began sports specific activities and were allowed to return to unrestricted activity at week 8. Foot and Ankle Ability Measure (FAAM), Visual Analog Score (VAS), Tegner Score, and range of motion measurements were performed. Statistical analysis was done to determine averages, ranges, and standard deviations of scores. Paired t-test was utilized to find statistically significant differences in scores.Results:Eighty-five patients (42 males, 43 females; average age 30.42 years) were available at a minimum of 24 months post- operatively (range 24-68). Postoperatively, average VAS scores fell to 0.85 from 4.67, (p<2.2e-16), average FAAM ADL scores rose from 69.44 to 93.09, (p<2.2e-16), average FAAM Sports scores rose from 49.76 to 89.61. (p<2.2e-16), average Ankle ROM scores decreased from 56.12o to 54.76o, (p=.001523) and average HF ROM decreased from 20.07o to 18.19o (p=1.225e-11). The average Tegner score postoperatively was 7.45 (4-10). Patients reported 75% excellent, 24% good, and 1% fair results. Average time to desired level of activity was 5.14 months. There were 5 complications: one wound dehiscence, 2 cases of anterolateral impingement, and two cases of superficial peroneal neuritis. There was no recurrent instability.Conclusion:The results indicate that acclerated rehabilitation after arthroscopic lateral ligament repair augmented with arthroscopically applied suture tape is a safe and effective procedure that produces favorable outcomes for patients with chronic recurrent ankle instability.

Real Life Population Pharmacokinetics Modelling of Eight Factors VIII in Patients with Severe Haemophilia A: Is It Always Relevant to Switch to an Extended Half-Life?

We retrospectively analysed the data files of 171 adults and 87 children/adolescents with severe haemophilia, except for 14 patients (moderate; minor) (1), to develop a global population pharmacokinetic (PK) model for eight factors VIII (FVIII) that could estimate individual PK parameters for targeting the desired level of FVIII activity (FVIII:C); and (2) to compare half-life (HL) in patients switching from a standard half-life (SHL) to an extended half-life (EHL) and evaluate the relevance of the switch. One-stage clotting assay for the measurement of FVIII activity (FVIII:C, IU/mL) was used for population PK modelling. The software, Monolix version 2019R1, was used for non-linear mixed-effects modelling. A linear two-compartment model best described FVIII:C. The estimated PK parameters (between-subject variability) were: 2640 mL (23.2%) for volume of central compartment (V1), 339 mL (46.8%) for volume of peripheral compartment (V2), 135 mL/h for Q (fixed random effect), and 204 mL/h (34.9%) for clearance (Cl). Weight, age, and categorical covariate EHL were found to influence Cl and only weight for V1. This model can be used for all of the FVIII cited in the study. Moreover, we demonstrated, in accordance with previous studies, that Elocta had longer half-life (EHL) than SHL (mean ratio: 1.48) as compared to Advate, Factane, Kogenate, Novoeight, and Refacto.

Sit Back or Dig In: The Role of Activity Level in Landscape Market Segmentation

Activity level, or the amount of action/interaction with a product, can be an indication of interest in a product category and influences purchases. Our goal was to assess the overall market for landscape plants using consumers’ activity level from the active/passive continuum proposed by Pine and Gilmore (2011). An online survey instrument was administered to invitees from a national online panel from 7 to 13 Sept. 2016 yielding 1543 useful responses. Factor analysis of 23 items adapted from a previous study revealed five factors, including one active factor and a separate passive factor. These two factors were used in the present study as a basis for a k-means cluster analysis. Two clusters emerged and were labeled “Active Engagement” and “Obligatory Passive Engagement” in landscape activities. We compared cluster means for all five factors and found the Active cluster purchased more plants of all types as well as had greater landscape pride and desire for a low (water) input landscape. Members of the Active cluster were from higher income and education households which were slightly larger and more likely to have Caucasian residents compared with the Passive cluster. In practice, retail employees and landscape professionals might initially ask about consumers’ activity level desired in the landscape as a screening question. Subsequent assistance in design and/or plant selection/purchase could then be tailored toward the desired activity level.

How to Steer and Control ERK and the ERK Signaling Cascade Exemplified by Looking at Cardiac Insufficiency.

Mathematical optimization framework allows the identification of certain nodes within a signaling network. In this work, we analyzed the complex extracellular-signal-regulated kinase 1 and 2 (ERK1/2) cascade in cardiomyocytes using the framework to find efficient adjustment screws for this cascade that is important for cardiomyocyte survival and maladaptive heart muscle growth. We modeled optimal pharmacological intervention points that are beneficial for the heart, but avoid the occurrence of a maladaptive ERK1/2 modification, the autophosphorylation of ERK at threonine 188 (ERK phosphorylation), which causes cardiac hypertrophy. For this purpose, a network of a cardiomyocyte that was fitted to experimental data was equipped with external stimuli that model the pharmacological intervention points. Specifically, two situations were considered. In the first one, the cardiomyocyte was driven to a desired expression level with different treatment strategies. These strategies were quantified with respect to beneficial effects and maleficent side effects and then which one is the best treatment strategy was evaluated. In the second situation, it was shown how to model constitutively activated pathways and how to identify drug targets to obtain a desired activity level that is associated with a healthy state and in contrast to the maleficent expression pattern caused by the constitutively activated pathway. An implementation of the algorithms used for the calculations is also presented in this paper, which simplifies the application of the presented framework for drug targeting, optimal drug combinations and the systematic and automatic search for pharmacological intervention points. The codes were designed such that they can be combined with any mathematical model given by ordinary differential equations.

Modified Valenti Arthroplasty in Running and Jumping Athletes With Hallux Limitus/Rigidus: Analysis of One Hundred Procedures

Despite hallux limitus/rigidus being a common condition, results of surgical procedures specifically pertaining to athletes are scarce. The results of 100 modified Valenti procedures, prospectively studied from January 2000 to June 2016 with an average 49.17 months of follow-up, are presented evaluating demographics, sport, time and ability to return to activity (RTA), decreased desired activity level, and need for additional surgery. Inclusion criteria included athletes who have exhausted conservative care without relief of daily pain, dorsiflexion <20°, and grade ≥2. Seventeen had grade 2, 79 had grade 3, and 4 had grade 4 disease. RTA for the 89 procedures where exact time could be determined was 9.25 weeks; however, 100% were confirmed to RTA to some degree. The RTA of dancers and runners (the largest portion of the cohort at 76) was around 8 weeks, whereas soccer players were the slowest at >16 weeks, which was significant. There was no other significant difference in RTA between sport, sex, or grade of hallux limitus/rigidus except for between runners and soccer players. Six patients (6%) stated a decreased desire to activity, although this was not a significant finding. The modified Valenti procedure is a safe and highly effective treatment for running and jumping athletes limited by hallux limitus/rigidus because 94% of patients were able to return to their desired level of activity.

Lower Limb Deformity and Total Knee Replacement

Abstract As the population becomes more active and life expectancy increases, gonarthrosis has proportions of epidemics. Total knee arthroplasty (TKA) is an intervention that decreases pain and gives the patients the possibility of quickly returning to the desired level of activity. It is an intervention with a patient satisfaction rate of about 90-95% with a survival of the implant over 15 years of 90%. When dealing with TKA the following elements should be taken into account: clinical examination (walking analysis), leg deformities and knee alignment (foot deformation management), posterior tibial tendon dysfunction, cavovarus foot, posttraumatic deformity, neuropathic arthropathies, ankle arthrosis, foot deformities and knee arthroplasty. Ankle or foot deformity may be causes of progression of gonarthrosis or a TKA failure. Post-operative alignment of TKA is an extremely important element in the long-term survival of the prosthesis. By improving biomechanical alignment of the complete pelvic limb, TKA survival and patient satisfaction will increase.

Modeling hydrodynamic cavitation in venturi: influence of venturi configuration on inception and extent of cavitation

Hydrodynamic cavitation (HC) is useful for intensifying a wide variety of industrial applications including biofuel production, emulsion preparation, and wastewater treatment. Venturi is one of the most widely used devices for HC. Despite the wide spread use, the role and interactions among various design and operating parameters on generated cavitation is not yet adequately understood. This article presents results of computational investigation into the cavitation characteristics of different venturi designs over a range of operating conditions. Influence of the key geometric parameters such as the length of venturi throat and diffuser angle on the inception and extent of cavitation is discussed quantitatively. Formulation and solution of multiphase computational fluid dynamics (CFD) models are presented. Appropriate turbulence and cavitation models are selected and solved using a commercial CFD code. Care was taken to eliminate the influence of numerical parameters like mesh density, discretization scheme, and convergence criteria. The computational model was validated by comparing simulated results with three published data sets. The simulated results in terms of velocity and pressure gradients, vapor volume fractions and turbulence quantities, and so on, are critically analyzed and discussed. Diffuser angle was found to have a significant influence on cavitation inception and evolution. The length of the venturi throat has relatively less impact on cavitation inception and evolution compared to the diffuser angle. The models and simulated flow field were used to simulate detailed time–pressure histories for individual vapor cavities, including turbulent fluctuations. This in turn can be used to simulate cavity collapse and overall performance of HC device as a reactor. The presented results offer useful guidance to the designer of HC devices, identifying key operating and design parameters that can be manipulated to achieve the desired level of cavitational activity. The presented approach and results also offer a useful means to compare and to evaluate different designs of cavitation devices and operating parameters. © 2018 American Institute of Chemical Engineers AIChE J, 65: 421–433, 2019

Modelling of hydrodynamic cavitation with orifice: Influence of different orifice designs

Hydrodynamic cavitation (HC) may be harnessed to intensify a range of industrial processes, and orifice devices are one of the most widely used for HC. Despite the wide spread use, the influence of various design and operating parameters on generated cavitation is not yet adequately understood. This paper presents results of computational investigation into cavitation in different orifice designs over a range of operating conditions. Key geometric parameters like orifice thickness, hole inlet sharpness and wall angle on the cavitation behaviour is discussed quantitatively. Formulation and numerical solution of multiphase computational fluid dynamics (CFD) models are presented. The simulated results in terms of velocity and pressure gradients, vapour volume fractions and turbulence quantities etc. are critically analysed and discussed. Orifice thickness was found to significantly influence cavitation behaviour, with the pressure ratio required to initiate cavitation found to vary by a factor of 10 for orifice thickness to diameter (l/d) ratios in the range of 0–5. Inlet radius similarly has a pronounced effect on cavitational activity. The results offer useful guidance to the designer of HC devices, identifying key parameters that can be manipulated to achieve the desired level of cavitational activity at optimised hydrodynamic efficiencies. The models can be used to simulate detailed time-pressure histories for individual vapour cavities, including turbulent fluctuations. This in turn can be used to simulate cavity collapse and overall performance of HC device. The presented approach and results offer a useful means to compare and evaluate different cavitation device designs and operating parameters.

Formulation Optimization and Performance Evaluation of Papain and Clove Oil based Chemo-mechanical Caries Removing Gel

Objective: To formulate and optimise stable caries removing gel using naturally extracted papain and clove, for non– invasive chemo–mechanical removal of dental caries. Methodology: Gel formulation was prepared using natural polymer such as pectin along with other excipients and optimized for desired level of papain activity and viscosity for effective application on carious tooth using 32 factorial design. Optimized formulation was evaluated for its physicochemical properties, in–vitro antibacterial activity and ex-vivo chemo-mechanical performance. Results: FTIR and DSC studies confirmed compatibility of papain with other excipients. Formulation with ratio of 2.5: 2.5: 0.225 pectin : propylene glycol : triethanolamine was found to give stable gel with viscosity of 7800cp, proteolytic activity of 91.64% with satisfactory in-vitro antibacterial activity and ex-vivo chemomechanical performance. Conclusion: Papain and clove containing chemo-mechanical caries removing gel can serve as potential alternative to other invasive caries removing techniques which will also reduce chances of microbial infection at the site of application with symptomatic pain relief. Key words: Clove, Chemomechanical removal, Dental caries, ex-vivo performance, Papain.

Immediate Unrestricted Weight Bearing with Simple Stirrup Brace Following Single Anchor Lateral Ankle Ligament Stabilization

Category: Ankle Introduction/Purpose: Anatomic lateral ankle ligament reconstruction has been shown to reliably restore the functional stability of the joint. Current orthopedic literature supports accelerated rehabilitation and protected weight bearing advancement as a safe and effective means to timely patient recovery. To our knowledge, there have not been clinical outcome reports of a protocol utilizing immediate unrestricted weight bearing in a stirrup brace following single anchor lateral ligament stabilization. The purpose of this study is to report on a series of patients treated with a more progressive protocol resulting in durable ankle stability and favorable clinical outcomes. Methods: A total of 28 patients with chronic lateral ankle ligament instability who failed conservative management underwent arthroscopy and modified Brostrom-Gould lateral ligament reconstruction between 2014 and 2015 were identified. The anterior talofibular and calcaneofibular ligaments were released from the fibula and advanced using one double-loaded metallic 3.5 mm suture anchor. Immediate unrestricted full weightbearing in a stirrup brace was allowed from the first postoperative day and accelerated physical therapy was initiated at 2 weeks postoperatively. Patients were assessed preoperatively, and at a minimum 1- year follow-up, using the AOFAS Hindfoot scale and VAS pain score. Additional postoperative outcome measures included the FAOS and a custom clinical questionnaire. Range of motion, ligamentous stability and single-blinded examination with Star Excursion Balance Test (SEBT) functional testing were performed postoperatively. Complication and recurrent instability rates were also recorded. Results: Twelve patients participated in the study (8F, 4 M). Mean age at final follow-up was 49 years (21-70). Average follow-up was 21 months (16 to 26). Average satisfaction score was 94%, and all patients reported they would have the procedure again. AOFAS Hindfoot score and VAS improved significantly from preoperative to postoperative, respectively (55.6 to 89.8, 5.4 to 1.6). Average postoperative FAOS score was 80.3 (51.8-100) . No measurable difference was observed on examination of range of motion, ligamentous stability, or SEBT testing in the anterior, posterolateral or posteromedial planes of the contralateral side, respectively (61.5 to 62.2 cm, 62.4 to 64.1 cm, 56.4 to 57.6 cm). No patients reported recurrent instability. Conclusion: This study demonstrates that anterior talofibular ligament and calcaneofibular ligament advancement utilizing a single 3.5 mm anchor construct followed by immediate unrestricted weight bearing is a safe and effective protocol for the treatment of chronic lateral ankle instability. Ligamentous stability was achieved and maintained in all patients across a wide variety of patient ages and desired activity levels. Patient satisfaction was excellent. This surgical technique and postoperative protocol may help reduce surgical time and implant cost, and may facilitate a more timely return to preinjury functional level.