7 research outputs found
Design, construction and field testing of a manually feeding semiautomatic sugarcane dud chipper
No full textSugarcane is the main sugar crop, and sugar is an important agricultural product in Egypt. There are many problems with the technology used in the current planting method of sugarcane, which has a great impact on the planting quality of sugarcane, which have a series of problems, such as low cutting efficiency and poor quality. Therefore, the aim of the current study was to design, construct, and field testing of a semiautomatic sugarcane bud chipper assisted with pivot knives for cutting sugarcane buds and germinating them in plastic trays inside a greenhouse until they reached an average length of 35 cm, and then planting them in the field. In the field tests five cutting speeds (35, 40, 45, 50, and 56 rpm. (Revolution Per minute), three cutting knives (1.5, 2.0, and 2.5 mm) were used for cutting sugarcane stalks with four different diameters (1.32, 1.82, 2.43, and 2.68 cm). The obtained results showed that the values of the damage index and invisible losses were within acceptable limits (ranging between - 1.0 and 0.0) for all the variables under the test. Still, the lowest damage index and invisible losses were recorded with the buds that were cut with a knife of 1.5 mm thickness and cutting speeds less than 50 rpm. The skipping rate increases with the increase in cutting speed and stalk diameter, ranging between 0.0 to 13%. The maximum machine productivity was 110 Buds per minute at a cutting speed of 35 rpm and stalk diameter of 1.32 cm. The paper's findings have important application values for promoting the designing and development of sugarcane bud chipper and sugarcane planting technology in the future
Quantification of van der Waals forces in bimodal and trimodal AFM
No full textThis article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Santos, S. [et al.]. Quantification of van der Waals forces in bimodal and trimodal AFM. "The Journal of chemical physics", 28 Maig 2023, vol. 158, núm. 20, article 204703 and may be found at https://doi.org/10.1063/5.0154196.The multifrequency formalism is generalized and exploited to quantify attractive forces, i.e., van der Waals interactions, with small amplitudes or gentle forces in bimodal and trimodal atomic force microscopy (AFM). The multifrequency force spectroscopy formalism with higher modes, including trimodal AFM, can outperform bimodal AFM for material property quantification. Bimodal AFM with the second mode is valid when the drive amplitude of the first mode is approximately an order of magnitude larger than that of the second mode. The error increases in the second mode but decreases in the third mode with a decreasing drive amplitude ratio. Externally driving with higher modes provides a means to extract information from higher force derivatives while enhancing the range of parameter space where the multifrequency formalism holds. Thus, the present approach is compatible with robustly quantifying weak long range forces while extending the number of channels available for high resolution.Peer ReviewedPostprint (published version
Corrigendum to “Thermoresponsive nanofibers loaded with antimicrobial α-aminophosphonate-o/w emulsion supported by cellulose nanocrystals for smart wound care patches” [Int. J. Biol. Macromol. 233 (2023) 123655–123667] (International Journal of Biological Macromolecules (2023) 233, (S0141813023005482), (10.1016/j.ijbiomac.2023.123655))
No full textThe authors regret the wrong description of the affiliation for the third author (Dr. Tharwat I. Shaheen). He is affiliated with the Textile Research and Technology Institute, National Research Centre, Dokki, Giza, Egypt (letter c) not the Chemistry Department, Faculty of Science, New Mansoura University, New Mansoura City, Egypt (letter d). The letter c should be associated with his name, not d. The authors would like to apologise for any inconvenience caused
Machine learning assisted multifrequency AFM: Force model prediction
No full textMultifrequency atomic force microscopy (AFM) enhances resolving power, provides extra contrast channels, and is equipped with a formalism to quantify material properties pixel by pixel. On the other hand, multifrequency AFM lacks the ability to extract and examine the profile to validate a given force model while scanning. We propose exploiting data-driven algorithms, i.e., machine learning packages, to predict the optimum force model from the observables of multifrequency AFM pixel by pixel. This approach allows distinguishing between different phenomena and selecting a suitable force model directly from observables. We generate predictive models using simulation data. Finally, the formalism of multifrequency AFM can be employed to analytically recover material properties by inputting the right force model
The long-term effectiveness of efavirenz-based combination antiretroviral therapy, the impact of pharmacogenomics and pharmacokinetic interaction of artemisinin-based antimalarial therapy on efavirenz exposure among Ghanaian HIV-infected patients
No full textDr. Fred Stephen Sarfo, The long-term effectiveness of efavirenz-based combination antiretroviral therapy, the impact of pharmacogenomics and pharmacokinetic interaction of artemisinin-based antimalarial therapy on efavirenz exposure among Ghanaian HIV-infected patients. PhD dissertation, Durham University, January 2013.
Introduction: In sub-Saharan Africa, HIV treatment is initiated with combination of antiretroviral medications comprising of a backbone of either stavudine or zidovudine plus lamivudine with a non-nucleoside reverse transcriptase inhibitor of either efavirenz or nevirapine. Efavirenz is highly efficacious, durable and well tolerated. The risk for toxicity of efavirenz is determined by several factors including single nucleotide polymorphisms in the hepatic enzymes responsible for its metabolism and concurrently administered medications such as antimalarials, which share common metabolic pathways. The aims of this dissertation are to assess the long-term effectiveness of efavirenz-based antiretroviral therapy and the impact of pharmogenomics and pharmacokinetic interactions of artemisinin-based antimalarial therapy on efavirenz exposure among Ghanaian HIV-infected patients.
Methods: The effectiveness of efavirenz- compared with nevirapine-based antiretroviral therapy was assessed retrospectively in nearly 4000 patients starting treatment between 2004 and 2010. The main outcome measure was a composite of toxicity, disease progression and attrition, and CD4 count changes. A prospective pharmacokinetic study of artesunate and efavirenz was conducted among 22 HIV-infected and 21 controls. Plasma efavirenz and artesunate/ dihydroartemisinin concentrations were measured using validated and standardised methods. Genotyping for single nucleotide polymorphisms in CYP2B6 G516T, T983C; CYP2A6*9B, UGT2B7*735 and *802 as well as CAR rs2307424 were performed for 800 patients with real-time polymerase chain reaction with allelic discrimination.
Results: Antiretroviral therapy was associated with robust CD4 increases. Efavirenz was comparable with nevirapine in composite outcomes but better tolerated. Artesunate was well tolerated when administered to HIV-infected patients on efavirenz. Single nucleotide polymorphisms in the CYP2B6 G516T and T983C were associated with increased plasma efavirenz concentrations.
Conclusions/Recommendation: Among this Ghanaian cohort, both efavirenz and nevirapine-based antiretroviral therapy were effective. The better tolerability of efavirenz compared with nevirapine means it can be safely used as the preferred first line non-nucleoside reverse transcriptase inhibitor in sub-Saharan Africa
Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy
No full textBackground
The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy.
Methods
In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation.
Results
Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89·6 per cent) compared with that in countries with a middle (753 of 1242, 60·6 per cent; odds ratio (OR) 0·17, 95 per cent c.i. 0·14 to 0·21, P < 0·001) or low (363 of 860, 42·2 per cent; OR 0·08, 0·07 to 0·10, P < 0·001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high‐HDI countries (risk difference −9·4 (95 per cent c.i. −11·9 to −6·9) per cent; P < 0·001), but the relationship was reversed in low‐HDI countries (+12·1 (+7·0 to +17·3) per cent; P < 0·001). In multivariable models, checklist use was associated with a lower 30‐day perioperative mortality (OR 0·60, 0·50 to 0·73; P < 0·001). The greatest absolute benefit was seen for emergency surgery in low‐ and middle‐HDI countries.
Conclusion
Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low‐HDI countries was half that in high‐HDI countries
