Application of full factorial design to screen the factors influencing the wax deposition of Malaysian crude oil

Wax deposition in production pipelines and transportation tubing from offshore to onshore is critical in the petroleum industry due to low-temperature conditions. The most significant popular approach to solve this issue is by inserting a wax inhibitor into the channel. This research aims to reduce the amount of wax formation of Malaysian crude oil by estimating the effective parameters using Design-Expert by full factorial design (FFD) method. Five parameters have been investigated, which are rotation speed (A), cold finger temperature (B), duration of experimental (C), the concentration of poly (stearyl acrylate-co-behenyl acrylate) (SABA) (D), and concentration of nano-silica SiO2 (E). The optimum conditions for reducing the amount of wax deposit have been identified using FFD at 300 rpm, 10 ℃, 1 h, 1200 ppm and 400 ppm, respectively. The amount of wax deposit estimated is 0.12 g. The regression model’s variance results revealed that the R2 value of 0.9876, showing 98.76% of the data variation, can be described by the model. The lack of fit is not important in comparison to the pure error, which is good. The lack of fit F value of 12.85 means that there is only a 7.41% probability that this huge can occur because of noise. The influence of cold finger temperature was reported as the main contributing factor in the formation of wax deposits compared to other factors. In addition, the interaction between factor B and factor C revealed the highest interaction effect on the wax deposition. In conclusion, the best interaction variables for wax inhibition can be determined using FFD. It is a valued tool to measure and detect the unique relations of two or more variables. As a result, the findings of this study can be used to develop a reliable model for predicting optimum conditions for reducing wax deposits and the associated costs and processing time.

Proximal heat stress up-regulates angiopoietin-1 in fingers and reduces the severity of Raynaud’s phenomenon in systemic sclerosis: a single-centre pilot study

ABSTRACT Objectives Raynaud’s phenomenon (RP) is a peripheral vascular disorder that frequently occurs in systemic sclerosis (SSc). Although therapeutic heating seems reasonable given that RP is elicited by cold stimuli, the effects of heating are still unclear. We examined the effects of heating applied on various body parts in SSc patients with RP of fingers. Methods Fourteen SSc patients heated their neck, elbows, and wrists with disposable heating pads for 1 week each. The visual analogue scale (VAS) for RP during each heating period was compared with that of each 1-week pre-treatment interval. On the day after the expiration of each heating period, their finger temperature, the finger blood flow, and angiogenesis-related factors (vascular endothelial growth factor, endostatin, angiopoietin-1, and angiopoietin-2) obtained from the cubital vein and fingertip were measured. Results The mean VAS was significantly reduced during the heating of the neck and elbows. Fingertip blood samples showed significantly increased angiopoietin-1 after each of the heating periods and increased endostatin after wrist heating. After the termination of heating, changes in finger temperature or blood flow could not be detected. Conclusions Heating the neck or elbows can alleviate RP in SSc. The heat up-regulates angiopoietin-1 in the fingers.

A prototype characterization of ExoFinger, a finger exoskeleton

This article presents an experimental characterization of ExoFinger, a finger exoskeleton for finger motion assistance. The exoskeletal device is analyzed in experimental lab activities that have been conducted with different users to characterize the operation performance and to demonstrate the adaptability of the proposed device. The behavior of this device is characterized in detail using sensors to measure finger motion and power consumption. Sensor measures also demonstrate the given motion assistance performance in terms of an electrical finger response and finger temperature by resulting in an efficient solution with a large motion range of a finger in assistance of recovering finger motion.

Relationship between peripheral vasospasm and visual field progression rates in patients with normal-tension glaucoma with low-teen intraocular pressure

Purpose To investigate the association between peripheral vasospasm and the visual field (VF) progression rate in patients with normal-tension glaucoma (NTG) with low-teen intraocular pressure (IOP). Methods The finger temperature of 113 NTG patients was measured before and after exposure to ice water using a Temperature gun (cold pressor test). These patients had confirmed VF progression, despite a low-teen IOP during a follow-up period of >5 years. VF progression rates were calculated as the slope of the visual field index (VFI) and mean deviation (MD) over time. Demographic, systemic, and ocular factors and VF progression rates were compared, based on the cold pressor test results. A regression analysis was used to investigate the factors affecting VF progression rates. Results Mean age, initial IOP, mean IOP during the follow-up period, and initial VF MD were 57.1 years, 15.8 mmHg, 12.0 mmHg, and -5.2 dB, respectively. When patients were divided into two groups (less vasospasm and more vasospasm) according to changes in temperature after exposure to ice water, the VF progression rate was significantly faster in the group with more vasospasm. In a multiple regression analysis, older age, worse initial VF MD, and greater decrease in finger temperature after ice water exposure were significantly associated with faster VF progression rates. Conclusion An excessive drop in finger temperature after exposure to ice water was significantly associated with faster VF progression in patients with low-teen NTG. This suggests that the blood flow in the optic nerve head may also be disturbed by peripheral vasospasm, accelerating glaucomatous damage regardless of IOP.

Thermal Disparity among Fingers and Its Amelioration by CO2-Water Bathing in Connective Tissue Disease Patients

Objective. Correlation between a low finger temperature and thermal disparity among fingers was studied in connective tissue disease (CTD) patients. Whether the thermal disparity may be ameliorated by hand immersion in a warm carbon dioxide- (CO2-) water bath was analyzed. Methods. CTD patients with suspected peripheral circulation disorder underwent a thermography test. From before to 30 min after hand immersion in CO2-water (CO2 bathing; 1000 ppm CO2, 42°C, 10 min), the nailfold temperatures were measured. The mean temperature (m-Temp) and the coefficient of variation of the temperature ( CV = SD / m ‐ Temp of one hand; the mean of CVs of both hands was adopted as the indicator of thermal disparity) were monitored. The correlation between m-Temp and CV was also analyzed. Results. Forty-seven (45 females and 2 males) patients were included, 32 of whom had Raynaud’s phenomenon. The m-Temp was 30.8 ± 3.0 ° C at the baseline, increased to 35.3 ± 1.0 ° C immediately after CO2 bathing, and remained significantly higher than that at the baseline until 30 min after ( 32.1 ± 1.9 ° C ). The CV was 0.0291 ± 0.0247 at the baseline, decreased to 0.0135 ± 0.0039 immediately after CO2 bathing, and remained significantly lower than the baseline until 30 min after ( 0.0163 ± 0.0143 ). Between m-Temp and CV, a negative correlation was observed throughout the measurements. Conclusion. Thermal disparity was observed at baseline measurement in CTD patients. Warm CO2 bathing markedly ameliorated the disparity, and this amelioration remained until after 30 min. Throughout the observation, the lower the m-Temp, the more severe the thermal disparity among fingers.

Enhanced Physiological Stress Response in Patients with Normal Tension Glaucoma during Hypoxia

Purpose. To investigate whether patients with normal tension glaucoma (NTG) show an enhanced stress response to reduced oxygen supply compared to age-matched healthy controls, measured by serum adrenaline and endothelin-1 (ET-1) levels and changes in distal finger temperature. Methods. A thorough clinical characterization of patients with NTG and age-matched controls was performed prior to inclusion in the study. Twelve patients with NTG and eleven healthy controls met the inclusion criteria and were enrolled in the study. All subjects underwent a two-day investigation. Participants were randomly exposed to either hypoxia or normoxia during the first visit. Hypoxia or normoxia was induced for two hours through a tightly fitting face mask. In addition, the peripheral circulation was assessed with a thermographic camera. Blood samples were obtained before, during, and after hypoxia or normoxia to evaluate systemic stress molecules such as catecholamines and ET-1 levels. Results. In patients with NTG, reduced oxygen supply induced an increase in peripheral blood adrenaline ( p < 0.05) and a decrease during recovery ( p < 0.01). A difference in distal finger temperature was shown in patients with NTG under hypoxia compared to normoxia (exposure: p < 0.05; recovery: p < 0.05). Hypoxia induced an increase in peripheral blood ET-1 levels in both groups (NTG: p < 0.01; controls: p < 0.05). Conclusion. Patients with NTG had an enhanced physiological stress response as a consequence of hypoxia compared with age-matched controls. Although more studies are needed, the present study supports the involvement of vascular risk factors in the pathophysiology of NTG.

Biofeedback App for Migraine: A Development and Usability Study (Preprint)

UNSTRUCTURED Background: Biofeedback is effective in treating migraine. However, widespread use is hampered by the need of a trained therapist and specialized equipment. Emerging digital health technology, including smartphones and wearables (mHealth), enables new ways of administering biofeedback. Currently, mHealth interventions for migraine appears feasible, but development processes and usability testing remain insufficient. Methods: In a prospective development and usability study, 18 adult migraine suffers completed a 4-week testing period of a biofeedback app connected to wearable sensors measuring muscle tension, finger temperature, and heart rate. The testing period was preceded by a pre-usability expectations interview and succeeded by a post-usability experience interview. In addition, an evaluation questionnaire was completed at week two and four. Usability and feasibility were analyzed and summarized quantitatively and qualitatively. Results: A total of 391 biofeedback sessions were completed with a median of 25 (17-28) per participant. Participants achieved an increase in maximum, minimum and mean temperature and a decrease in maximum heart rate over the course of biofeedback training sessions. Qualitative pre-expectations analysis revealed that participants expected to become better familiar with physical signals, gain more understanding of their migraine attacks, and noted that the app should be simple and understandable. Post-usability analysis indicated that participants had an overall positive user experience with some suggestions for improvement. The intervention was safe and tolerable. Conclusion: The app underwent a rigorous development process which indicated an overall positive user experience, good usability and high adherence rate. This study highlights the importance of usability testing in the development of mHealth apps.

Individual variations and sex differences in hemodynamics with percutaneous arterial oxygen saturation (SpO2) in young Andean highlanders in Bolivia

Background Many studies have reported specific adaptations to high altitude, but few studies have focused on physiological variations in high-altitude adaptation in Andean highlanders. This study aimed to investigate the relationships between SpO2 and related factors, including individual variations and sex differences, in Andean highlanders. Methods The participants were community-dwelling people in La Paz, Bolivia, aged 20 years and over (age range 20–34 years). A total of 50 men and 50 women participated in this study. Height, weight, SpO2, hemoglobin concentration, finger temperature, heart rate, and blood pressure were measured. Information about lifestyle was also obtained by interview. Results There were individual variations of SpO2 both in men (mean 89.9%, range 84.0–95.0%) and women (mean 91.0%, range 84.0–96.0%). On Student’s t test, men had significantly lower heart rate (p = 0.046) and SpO2 (p = 0.030) than women. On the other hand, men had significantly higher SBP (p < 0.001), hemoglobin (p < 0.001), and finger temperature (p = 0.004). In men, multiple stepwise regression analysis showed that a higher SpO2 was correlated with a lower heart rate (β = − 0.089, p = 0.007) and a higher finger temperature (β = 0.308, p = 0.030) (r2 for model = 0.18). In women, a higher SpO2 was significantly correlated with a higher finger temperature (β = 0.391, p = 0.015) (r2 for model = 0.12). A higher SpO2 was related to a higher finger temperature (β = 0.286, p = 0.014) and a lower heart rate (β = − 0.052, p = 0.029) in all participants (r2 for model = 0.21). Residual analysis showed that individual SpO2 values were randomly plotted. Conclusion Random plots of SpO2 on residual analysis indicated that these variations were random error, such as biological variation. A higher SpO2 was related to a lower heart rate and finger temperature in men, but a higher SpO2 was related to finger temperature in women. These results suggest that there are individual variations and sex differences in the hemodynamic responses of high-altitude adaptation in Andean highlanders.