Test Frequency Research Articles

Magnetorheological Damper Design Based on Improved H–B Model

Abstract To address the issues of sedimentation of the working medium,high sealing requirements, and rapid increase in stiffness under medium- and high-frequency excitation leading to severe energy dissipation in traditional magnetorheological dampers, a magnetorheological composite material with good sedimentation stability and low sealing requirements was prepared and tested. An improved Herschel–Bulkley model was established to characterize the mechanical properties of the composite material. Furthermore, a shear magnetorheological damper was designed and manufactured based on the composite material, and the performance response law of the damper under medium- and high-frequency excitation was tested by designed experiments. The results show that the dynamic stiffness of the damper increases from 4.83 × 105N/m to 6.32 × 105 N/m when the test frequency is increased from 5 Hz to 20 Hz under the current excitation of 3A, and the single-cycle energy consumption of the damper under the full-band is about 0.037J, which verified the energy consumption capacity of the designed magnetorheological damper under medium- and high-frequency vibrations.

Temporary Hearing Threshold Shift in California Sea Lions (Zalophus californianus) Due to a Noise Band Centered at 40 kHz and Comparison with Shifts Due to Lower-Frequency Sounds

California sea lions (Zalophus californianus) exposed to anthropogenic noise may experience temporary hearing threshold shift (TTS). The function used in regulations to protect their hearing from such damage in the Pacific Ocean is based on only one datapoint, so more data are needed. To determine their frequency-dependent susceptibility to noise-induced TTS, two California sea lions were exposed for 60 minutes to a continuous one-sixth-octave noise band (NB) centered at 40 kHz as the fatiguing sound, at sound pressure levels of 119 to 143 dB re 1 µPa, resulting in sound exposure levels (SELs) of 155 to 179 dB re 1 µPa2s. TTSs were quantified at the center frequency of the fatiguing sound and up to one octave above that frequency (at 40, 50, 56.5, 63, and 80 kHz). Statistically significant TTS occurred at all hearing test frequencies; higher SELs caused greater TTSs. Significant onset of TTS(1-4 min) occurred after exposure to a minimum SEL of 167 dB re 1 µPa2s—a shift of 5.2 dB at hearing frequency 56.5 kHz. At other hearing frequencies, onset of TTS1-4 occurred at SEL 173 dB re 1 µPa2s. TTSs1-4 ≤ 8 dB recovered within 12 min, and TTSs1-4 of > 8 dB recovered within 60 min. TTSs and hearing recovery patterns were similar in both subjects. Comparison with TTS data for the species’ hearing frequency range (0.6 to 40 kHz) shows that after exposure to fatiguing sound frequencies of 0.6, 1, 4, 8, and 16 kHz, the largest TTS1-4 occurred half an octave above the frequency of each of the fatiguing sounds. After exposure to fatiguing sound frequencies 2, 32, and 40 kHz, the largest TTS occurred at the frequency of the fatiguing sounds. Recovery patterns after exposure to the NB at 40 kHz were similar to those after exposure to NBs at 0.6, 1, 2, 4, 8, 16, and 32 kHz. Over almost the entire hearing range, the shape of the audiogram is a poor predictor of the shape of the TTS-onset function. The low TTS-onset SELs show that the hearing of California sea lions is more vulnerable to injury by anthropogenic sound in the oceans than was previously thought.

Assessing the Very High Cycle Fatigue Behavior and Frequency Effect of Structural Steel Welds

ABSTRACTThe very high cycle fatigue behavior of S275J2+N flux‐core arc welded joints was investigated using the ultrasonic fatigue testing method at a loading frequency of 20 kHz. A bespoke specimen design featuring the weld toe was employed to more suitably represent in‐service welded joints than typical ultrasonic fatigue testing specimens. This revealed that fracture occurs above 10 million cycles, beyond the classically accepted fatigue limit. Additionally, comparative fatigue tests were performed at 10 Hz to investigate the frequency effect on the fatigue behavior. A 35% increase in fatigue strength was measured at 20 kHz when compared to 10 Hz, indicating that a correction must be considered in the use of ultrasonic fatigue testing data for design purposes. Fracture surfaces for both test frequencies showed similar morphologies and typical characteristics for fatigue failures of ductile metals.

Pulmonary function testing patterns in patients recovering from COVID-19, a prospective observational study.

Objective: To determine the frequency of abnormal pulmonary function tests and their pattern after four weeks in patients recovering from COVID-19. Study Design: Survey-based Cross Sectional Observational study. Setting: COVID 19 Isolation Ward, Khyber Teaching Hospital, Peshawar. Period: June 23, 2021, to December 21, 2021. Methods: This study was conducted on 183 patients aged 18 – 70 years of either gender having severe or critical COVID-19 pneumonia necessitating admission to COVID-Unit were enrolled using a non-probability consecutive sampling technique. Discharged patients of COVID-19 were called for follow-up after 4 weeks of discharge, and a pulmonary function test was done to determine the frequency of abnormal pulmonary function tests and their pattern after COVID infection. Results: In our study total of 183 patients were enrolled with a mean age of 36.3±14.6 years. There were 53% male and 47% female patients. The mean height was 155.06 ± 13.3cm, the mean weight was 71.4±11.2 kg, and the mean BMI was 29.7±5.8kg/m2. Abnormal pulmonary function tests were present in 32.8% of patients. Among these patients, 49 (81.6%) had restrictive patterns, while 11(18.3%) patients had an obstructive pattern on spirometry. Conclusion: Patients infected with COVID-19 showed deranged lung function, with most patients having a restrictive type pattern 4 weeks after being discharged from the hospital.

Audio-vestibular dysfunction in rheumatoid arthritis associated secondary Sjogren syndrome, and its correlation to serum level of anticardiolipin and muscarinic type 3 receptors antibodies: a cross-sectional observational study

BackgroundIn secondary Sjogren syndrome (sSS), the presence and extent of hearing and vestibular abnormalities are controversial. Hence, to ascertain if individuals with Rheumatoid arthritis (RA) associated secondary Sjogren syndrome (sSS) had subclinical audio-vestibular impairment as well as to investigate whether serum anticardiolipin and muscarinic receptors type 3 antibodies had a role in its pathogenesis, this cross-sectional study was conducted on 50 RA patients with secondary Sjogren syndrome manifestations and 50 RA patients without such manifestations were included, along with 50 apparently healthy volunteers who were aged, and sex-matched as controls. Full history taking, Otologic examination, Immunologic evaluation, and Audio-vestibular assessment were done for all subjects.ResultsTwenty-five percent of our patients experienced subjective audio-vestibular symptoms. In the audiogram, 30 (60%) of the 50 RA patients with sSS and 5 (10%) of RA patients without sSS had abnormal hearing loss compared to only 4 (8%) of the controls (p ≤ 0.001) with a predominance of high-frequency sensorineural hearing loss. Also, 20% of our patients experienced a higher frequency of head-shaking nystagmus than they did (p ≤ 0.001). 30% had a statistically significant increase in the frequency of abnormal caloric test results as compared to either controls (0%) or RA patients without sSS (0%); p ≤ 0.001 Finally, all audio-vestibular symptoms and tests exhibit a strong positive correlation with muscarinic receptors type 3 and anticardiolipin antibodies.ConclusionThe use of muscarinic receptors type 3 and anticardiolipin antibodies are beneficial for early diagnosis of audio-vestibular dysfunction in RA-associated secondary Sjogren syndrome patients. Therefore, this study is important since it justifies rheumatologists’ screening for inner ear damage in their RA patients especially if associated with secondary Sjogren.

The overlap between type 1 diabetes and celiac disease in children and the role of tTG-IgA positivity in endoscopy decision.

Celiac Disease (CD)-related antibody positivity in children with Type 1 Diabetes (T1D) may fluctuate and become negative spontaneously. There are uncertainties about the optimal tTG-IgA titre and timing of endoscopy in the diagnosis of CD, and this study aimed to contribute to the debate on the tTGA-IgA threshold titre for endoscopy decisions in children with T1D. The data of 991 children with T1D who had undergone serologic evaluation for CD were analysed retrospectively. The tTG-IgA positivity rate and the upper limit of normal (ULN) tTG-IgA positivity were assessed. Participants were grouped according to the frequency, course and test results of tTG-IgA tests. Those with and without histopathologic diagnosis of CD by endoscopic biopsy were compared in terms of tTG-IgA screening time and tTG-IgA predictive values. In 10.2% (n:101) of all cases, tTG-IgA antibody was positive and endoscopic biopsy was performed in 68.3% (n:69) of these cases. Of all cases, 4.3% (n:43) were diagnosed with CD by endoscopic biopsy. A tTG-IgA titre of 7xULN and above was found to be the best predictive value for the diagnosis of CD with 79.1% sensitivity, 80.8% specificity 87.2% positive predictive value and 70% negative predictive value. Approximately 10% of antibody positive cases showed fluctuating and low titre positivity, and no CD was detected by endoscopic biopsy in the group with fluctuating antibody course. The results of our study suggest that endoscopy in children with tTG-IgA levels 7xULN or above may prevent both false positive results and missed cases.

Defining the Critical Requisites for Accurate Simulation of SARS-CoV-2 Viral Dynamics: Patient Characteristics and Data Collection Protocol.

Mathematical models of viral dynamics are crucial in understanding infection trajectories. However, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load data often includes limited sparse observations with significant heterogeneity. This study aims to: (1) understand the impact of patient characteristics in shaping the temporal viral load trajectory and (2) establish a data collection protocol (DCP) to reliably reconstruct individual viral load trajectories. We collected longitudinal viral load data for SARS-CoV-2 Delta and Omicron variants from 243 patients in Singapore (2021-2022). A viral dynamics model was calibrated using patients' age, symptom presence, and vaccination status. We accessed associations between these patient characteristics and aspects of viral dynamics using linear regression models. We evaluated the accuracy of viral load trajectory estimation under different simulated DCPs by varying patient numbers, test frequencies, and test intervals. Older unvaccinated individuals had a longer viral shedding duration due to lower infection and cell death rates. Higher peak viral loads were found in older, symptomatic, and vaccinated individuals, with earlier peaks in younger vaccinated individuals. Symptom presence and vaccination resulted in a shorter time from infection to diagnosis. To accurately estimate viral dynamics, more frequent tests, longer test intervals, and larger patient samples are required. For 500 patients, a 21-day follow-up with measurements every 3 days and an 8-day follow-up with daily measurements was optimal for the Delta and Omicron variants, respectively. Patient characteristics significantly impacted viral dynamics. Our analytic approach and recommended DCPs can enhance preparedness and response to emerging pathogens beyond SARS-CoV-2.

Impact of Severity of Sickle Cell Anemia on Auditory Discrimination Ability and Speech Perception in Noise.

Introduction Sickle cell anemia (SCA) is a genetic disorder with clinical manifestations due to circulatory changes, leading to adverse effects on the auditory system that might impact auditory processing, such as auditory discrimination and speech perception ability. This condition is associated with the severity level of anemia. Objective The purpose of the present study was to investigate the influence of anemia severity on auditory discrimination ability and speech perception in noise among SCA patients with normal hearing sensitivity. Methods A total of 52 normal-hearing adults diagnosed with SCA in the age range of 15 to 40 were grouped into mild, moderate, and severe, based on anemia severity. Auditory discrimination tests for frequency, intensity, and duration were evaluated at 500 and 4,000 Hz along with speech perception in noise (SPIN) at 0 dB SNR using the mlp toolbox in the MATLAB software, version 2014a (MathWorks, Natick, MA, USA). The IBM Statistical Package for Social Sciences (SPSS) version 26.0 (IBM Corp., Armonk, NY, USA) was used for statistical analysis. Results The results revealed an increase in median and interquartile range among anemia groups with increasing severity. Additionally, the median scores were found to be poorer for the higher frequency in all auditory discrimination tests than for the lower one. A regression in performance with an increase in severity for the SPIN test was observed. Conclusion The severity of anemia plays an important role in functional auditory processing deterioration. Circulatory changes secondary to SCA affected auditory discrimination processing and speech perception in noise. However, all auditory discrimination abilities are not necessarily affected equally.

Number of macula optical coherence tomography scans needed to detect glaucoma progression

BackgroundTo evaluate the impact of testing frequency on the time required to detect statistically significant glaucoma progression for ganglion cell complex (GCC) with optical coherence tomography (OCT).Materials and methodsFrom multicentre...

The Trapping Mechanism at the AlGaN/GaN Interface and the Turn-On Characteristics of the p-GaN Direct-Coupled FET Logic Inverters.

The trapping mechanism at the AlGaN/GaN interface in the p-GaN high electron mobility transistors (HEMTs) and its impact on the turn-on characteristics of direct-coupled FET logic (DCFL) inverters were investigated across various supply voltages (VDD) and test frequencies (fm). The frequency-conductance method identified two trap states at the AlGaN/GaN interface (trap activation energy Ec-ET ranges from 0.345 eV to 0.363 eV and 0.438 eV to 0.47 eV). As VDD increased from 1.5 V to 5 V, the interface traps captured more electrons, increasing the channel resistance (Rchannel) and drift-region resistance (Rdrift) of the p-GaN HEMTs and raising the low-level voltage (VOL) from 0.56 V to 1.01 V. At fm = 1 kHz, sufficient trapping and de-trapping led to a delay of 220 µs and a VOL instability of 320 mV. Additionally, as fm increased from 1 kHz to 200 kHz, a positive shift in the threshold voltage of p-GaN HEMTs occurred due to the dominance of trapping. This shift caused VOL to rise from 1.02 V to 1.40 V and extended the fall time (tfall) from 153 ns to 1 µs. This investigation enhances the understanding of DCFL GaN inverters' behaviors from the perspective of device physics on power switching applications.

Unveiling the Potential of Waste Materials: Investigating the Novel Approach of Using Scrap Fabric-Inner Tubes Composites for Sound Absorption

Scrap fabric and used inner tubes, typically considered waste with no economic value and potential environmental issues, are being repurposed as an alternative composite material. This study uses the compression molding method to analyze the use of polyester fabric scrap and inner tubes as soundproofing composites. The process variables include temperature, pressure, and the composition of the used tire fabric rubber. The temperature variables used are 140, 150, and 160°C. The pressure variables used are 8, 10, and 12 ton-forces (tf). The composition variables of the fabric-rubber weight ratio used are 50:50, 60:40, and 40:60. Samples printed with compression molding according to the process variable combination scheme are then tested using an impedance tube tester to determine the effectiveness of sound absorption that the composite can absorb. The soundproofing test standard with impedance tubes is ISO 10140, with 125, 250, 500, 750, 1000, and 2000 Hz test frequencies. The test results show that samples with a fabric-rubber ratio of 60:40, a pressure of 10 tf, and a temperature of 150°C have the highest sound absorption coefficient value at 2000 Hz, which is 0.90817, and a Noise Reduction Coefficient of 0.8114. This result shows that the combination of pressure, temperature, and weight composition affects the composite's density and porosity, which will then affect the soundproofing performance of the developed composite.

Use of Freestyle Libre 2.0 in children with type 1 diabetes mellitus and elevated HbA1c: Extension phase results after a 12-week randomized controlled trial.

To investigate extension phase outcomes with intermittently scanned continuous glucose monitoring (isCGM 2.0) in children with type 1 diabetes mellitus (T1DM) and elevated HbA1c (7.5-12.2% [58-110 mmol/mol]). One hundred children with T1DM aged 4-13 years were initially in a 12-week randomised controlled trial (RCT) comparing glycaemic outcomes with isCGM 2.0 (intervention group, n = 49) with self-monitored blood glucose (Control group, n = 51). After the 12-week RCT both groups were offered an extension phase with isCGM 2.0 for another 12 weeks. HbA1c, CGM metrics, psychological outcomes and device utilization attitudes were measured. After the initial 12-week RCT, 66 participants completed this 12-week extension: 36/49 (73%) and 30/51 (58.8%) from the isCGM/isCGM and Control/isCGM groups, respectively. In the isCGM/isCGM group, time below range 70 mg/dL (3.9 mmol/L) (TBR70) reduced from 10.7 ± 11.3% at baseline to 2.8 ± 2.8% and 2.1 ± 2.4% at 12 and 24 weeks, respectively (p < 0.01 for both 12 and 24 weeks). Glucose test frequency increased from 4.7 (2.7) at baseline to 10.7 (4.6) and 9.2 (4.7) at 12 and 24 weeks, respectively (p < 0.01 for both 12 and 24 weeks). The Control/isCGM group decreased TBR70 from 10.7 ± 7.4% at 12 weeks to 2.9 ± 2.8% at 24 weeks and increased daily glucose test frequency from 3.2 (1.6) to 10.7 (5.4) from 12 to 24 weeks (both p < 0.01). However, HbA1c and time in range (TIR) were non-significant at 24 weeks in both groups. Extension phase outcomes with intermittently scanned continuous glucose monitoring (isCGM 2.0) in children with T1DM and elevated HbA1c showed a sustained reduction in hypoglycaemia and increased testing frequency at 24 weeks.

Influence of DPYD gene polymorphisms on 5-Fluorouracil toxicities in Thai colorectal cancer patients

DPYD polymorphisms have been widely found to be related to 5-FU-induced toxicities. The aim of this study was to establish significant associations between five single-nucleotide polymorphisms of DPYD and 5-FU hematological toxicities in Thai colorectal cancer patients. The toxicities were analyzed at the first and second cycles of 5-FU administration in 75 patients. Genotyping was performed using TaqMan real-time PCR. The genotype frequencies of DPYD*2A,1905 + 1 G > A and DPYD 1774 C > T were all wild type. The frequencies of genetic testing for DPYD*5, 1627 A > G, DPYD 1896T > C, and DPYD*9A, 85 A > G were 37.30% (AG; 34.60%, GG; 2.70%), 32.00% (TC; 25.30%, CC; 6.70%), and 13.40% (AG; 10.70%, GG; 2.70%), respectively. The results reveal significant findings with neutropenia occurring in 100% (2/2) of the patients with homozygous variant DPYD*9A (GG) from the first cycle of treatment for both Grade 1–4 and Grade 3–4 toxicities (P = 0.003 and P < 0.001 respectively). DPYD *9A was related to Grade 1–4 leukopenia (P = 0.001) and both Grade 1–4 and severe thrombocytopenia (P < 0.001 and P < 0.001) in the first cycle. In the second cycle, DPYD*5 was shown to be closely associated with no Grade 1–4 toxicity (P = 0.02). However, we found that 100% (2/2) of patients carrying the homozygous variant (GG) DPYD*5, presented no significant toxicity, so, DPYD*5 may be a predictive marker of neutropenia in patients treated with 5-FU. These outcomes suggest that there may be an increased risk of developing 5-FU-induced neutropenia in patients carrying the DPYD*9A, which should be considered as part of the standard procedure.

Marine vibrator using electromagnetic acceleration

Abstract Optimizing the low-frequency performance of the vibrator is an important direction for the development of marine vibrators. In order to solve the problems of high resonance frequency, small low-frequency displacement and difficulty in generating low-frequency signals of marine vibrators, this study proposed a strategy of high-frequency and low-frequency distributed vibration. In the low-frequency part, electromagnetic acceleration is innovatively combined with the vibrator, and the Ansys Maxwell finite element simulation software is used for analysis. In the high-frequency part, the traditional moving coil vibrator structure is used, and experimental verification is carried out in the anechoic tank. The simulation results show that the low-frequency part of the marine vibrator using electromagnetic acceleration can achieve low-frequency vibration, and the vibration is still relatively stable. The experimental results of the anechoic tank show that within the test frequency band, the sound source level generated meets the requirements of seismic exploration for high-frequency vibrators. This study uses the frequency segmentation strategy to improve the overall working efficiency of the vibrator and provides new ideas for the design of marine vibrators.

High cycle and very high cycle fatigue behavior of additively manufactured Inconel 718: Effects of stress-relieving, surface texture, part orientation, and test frequency

High cycle and very high cycle fatigue behavior of additively manufactured Inconel 718: Effects of stress-relieving, surface texture, part orientation, and test frequency

Seasonal patterns of myositis-specific and myositis-associated autoantibodies in Italy: Seasonal patterns of myositis autoantibodies.

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of systemic autoimmune disorders affecting skeletal muscles but also other organs. There are different forms of IIM, each with peculiar clinical manifestations and prognosis. Accordingly, several autoantibodies have been described in IIM, with different prevalence in the different forms of the disease. The etiopathogenesis of IIM is still unclear, although environmental agents play certainly a role to trigger disease development in genetically predisposed individuals. Supporting this notion, some reports suggest that the incidence of IIM may be different throughout the year. In this work, we tested if the detection of autoantibodies typically observed in IIM has a seasonal pattern. We collected serological data from line immunoassays (LIA) performed on 4277 patients with suspected IIM from January 2018 to December 2020 in ten Italian hospitals. Myositis-specific and myositis-associated autoantibodies were evaluated by line-immunoassay. Our findings demonstrate that absolute numbers of anti-MDA5, anti-PM-Scl75, anti-Mi2b and anti-TIF1ɣ autoantibodies are more frequently detected in autumn-winter than in spring-summer. However, only anti-PM-Scl75 and anti-MDA5 display a similar pattern when analyzing frequencies of positive tests (for anti-PM-Scl75 100 positive tests and 2107 negative tests from September to February; 55 positive tests and 1903 negative tests from March to August, p = 0.003; for anti-MDA5 34 positive tests and 1983 negative tests from September to February; 17 positive tests and 1760 negative tests from March to August, p = 0.051). These findings suggests that triggering agents promoting the development of these autoantibodies have a specific seasonal pattern.

Duration and Frequency of Spirometry Needed to Accurately Reflect Annualized Change of FEV1 in Chronic Obstructive Pulmonary Disease.

Rationale: The slope of decline in forced expiratory volume in 1 second (FEV1) is commonly used to reflect the rate of disease progression for descriptive studies and therapeutic trials in chronic obstructive pulmonary disease (COPD). The frequency and duration of spirometric testing needed to report the true slope are unknown. Objectives: We sought to define the minimum frequency and follow-up duration needed to accurately describe the annualized rate of FEV1 change among patients with moderate to very severe COPD. Methods: We performed a post hoc analysis of the annualized rate of FEV1 change among 4,412 subjects previously enrolled in the 4-year Understanding Potential Long-Term Impacts on Function with Tiotropium-or, UPLIFT-trial of tiotropium versus placebo. Slope estimates were modeled for different iterations of semiannual or annual testing over a variable duration up to 42 months. All models were compared with a reference of semiannual spirometry for 42 months. Results: The overall annual rate of postbronchodilator FEV1 decline measured semiannually for 42 months (44.6 ml; 95% confidence interval [CI] = 42.5-46.6) did not differ significantly from annual spirometry over the same period (43.7 ml; 95% CI = 41.3-46.1) or semiannual spirometry over the first 2 years (44.3 ml; 95% CI = 41.1-47.5). Agreement was consistent for two follow-up values as far as 24 months apart (43.3 ml; 95% CI = 39.9-46.8). Models that are based on less than two follow-up values or a duration less than 18 months were characterized by relative underestimation of the slope. Conclusions: In a large cohort of patients with moderate to very severe COPD, the annualized rate of change in FEV1 was accurately represented by a minimum of two annual follow-up measurements over 18 months compared with semiannual testing over 42 months.

Pulsatile fatigue testing of arterial stents with radially applied load

Abstract Pulsatile fatigue testing is a basic requirement for arterial stents, however, there are several opportunities to setup and conduct the testing. The recently published standard guide ASTM F2477:2023 provides specific guidance, in particular includes the pressure controlled test method applying an outer hydraulic pressure to the test samples. The current work describes this approach, and demonstrates that the technical requirements can be met successfully. In addition, some inherent advantages are discussed, e.g. accuracy of pressure loading, absence of stent migration and potential high test frequencies.

Demographics, clinical profiles and healthcare utilization of patients with beta thalassemia major: A single centered study

Thalassemia is an inherited autosomal recessive blood disorder that occurs due to abnormal form of hemoglobin in the blood. It is an autosomal recessive condition caused by decreased formation of alpha or beta chains of hemoglobin. Pakistan continues to suffer from a high thalassemia burden with statistics rising every year. With around 10 million carriers across the country, it is reported that each year, around 5000 children are diagnosed with thalassemia. The aim of this study is to bridge the gap between the problems faced by thalassemic patients in Pakistan and the facilities not available to them as compared to the developed countries. Method: A cross- sectional study was conducted with the duration of this study was 12 months. The data was collected from six tertiary care hospitals and eight Thalassemia centers, with the selection based on the accessibility of data. The inclusion criteria for the study was: a clinical diagnosis of Beta Thalassemia Major and age group between 1-18 years, irrespective of gender. The exclusion criteria included patients who were over 18 years of age and had comorbidities or complications other than Beta Thalassemia Major, as well as those who did not give consent. A questionnaire was circulated to record the data. It had two parts. The first part included demographics and the second part had close-ended questions related to the treatment of Thalassemia. Results: The total number of participants were 255 in which 122 (47.8%) were males and 133 (52.2%) were females. A positive correlation was observed between age and hospital visits, showing that an increase in age was associated with an increase in hospital visits among Beta Thalassemia patients (p value&lt; 0.05) (CL:95%). Positive correlation was observed between the age of patients and the number of Liver Function tests. (p-value&lt;0.05) (CL: 95%), viral profile done per year and age among B-thalassemia major patients. (p-value&lt; 0.05) (CL:95%) and between age and cbc conducted per month (p-value &lt; 0.05). Another positive correlation was observed between weight and frequency of blood transfusions in B-thalassemia major patients (p-value&lt; 0.05) (CL:95%) and weight and liver function tests conducted per year among thalassemia patients. (p-value&lt; 0.05) (CL:95%). Conclusion: This study aims to highlight the problems faced by thalassemia patients in Pakistan and the facilities not available to them compared to developed countries. A cross-sectional study was conducted for 12 months, collecting data from six tertiary care hospitals and eight Thalassemia centers. A questionnaire was used to record data on demographics and close-ended questions related to thalassemia treatment. Positive correlations were observed between age and hospital visits, liver function tests, viral profiles, and CBCs conducted. Weight was positively correlated with the frequency of blood transfusions and liver function tests conducted per year.

Redefining low-threshold buprenorphine access in an integrated mobile clinic program: Factors associated with treatment retention

IntroductionThe Spot mobile clinic provides low-threshold buprenorphine integrated with clinical and social services in Baltimore City, MD. In 2021, The Spot modified practices to improve engagement including providing extended prescriptions, reducing frequency of toxicology testing, giving up to six months to stabilize on medication, offering maximum doses (up to 32 mg total) daily, and utilizing telemedicine. This study characterizes care retention by examining both the total time in care and the percentage of time with buprenorphine prescription coverage during these practice changes, and examines factors associated with retention. MethodsThis retrospective cohort study includes patients (n = 341) who received a buprenorphine prescription who initiated care on The Spot mobile clinic from September 2021 to October 2022, with follow-up through October 2023. We utilized the Cox proportional hazards model and Kaplan-Meier survival analyses to assess differences in care retention by the factors of patient demographics and clinical characteristics. Additionally, we performed sensitivity analyses using Poisson regression to examine differences between patients with 80 % or greater time with active prescription coverage versus <80 % of time with active prescription coverage. ResultsAfter practice setting changes, retention in care at 90 days was 60 %. Patients whose maximum daily buprenorphine dose was 28 to 32 mg were 80 % less likely to discontinue treatment over the study period than those prescribed ≤16 mg (adjusted hazard ratio of discontinuation: 0.2 [95 % CI: 0.1–0.3]). Engaging in wound care or hepatitis C treatment was associated with higher retention in care, and individuals experiencing homelessness remained engaged at rates comparable to stably housed patients. ConclusionPractice changes aimed to improve access to patient-centered, low-threshold buprenorphine treatment may increase retention in care. Notably, higher doses of buprenorphine and integrated treatment with wound care and hepatitis C treatment were associated with increased retention. Due to gaps in patient care, retention metrics should incorporate total time in care as well as percentage of time with an active buprenorphine prescription.