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Article ; Online: Dose Distribution Scaling and Validation of Ultraviolet Photoreactors Using Dimensional Analysis.

Sangwan, Nikhil / Ahmed, Yousra M / Blatchley, Ernest R

Environmental science & technology

2023 Volume 57, Issue 43, Page(s) 16707–16717

Abstract: Ultraviolet (UV) disinfection is commonly applied in the treatment of drinking water and wastewater. The performance of UV disinfection systems is governed by the UV dose distribution delivered to the fluid, which is an intrinsic characteristic of the ... ...

Abstract	Ultraviolet (UV) disinfection is commonly applied in the treatment of drinking water and wastewater. The performance of UV disinfection systems is governed by the UV dose distribution delivered to the fluid, which is an intrinsic characteristic of the reactor under a given operating condition. Current design and validation approaches are based on empirical methods that are expensive to apply and provide limited information about the UV photoreactor behavior. To address this issue, a dose distribution scaling method was developed based on dimensional analysis (i.e., application of the Buckingham-π theorem). Three dimensionless groups representing UV dose, reactor geometry, and UV absorption behavior were defined. Using these groups, the approach was applied for the analysis of 15 operating conditions, defined by process variables of volumetric flow rate, UV transmittance, and lamp power. The approach was demonstrated to allow scaling of the dose distribution with these critical, dimensionless variables and yielded close agreement between predictions of disinfection efficacy against MS2 and
MeSH term(s)	Escherichia coli ; Ultraviolet Rays ; Disinfection/methods ; Wastewater ; Water Purification/methods
Chemical Substances	Wastewater
Language	English
Publishing date	2023-10-17
Publishing country	United States
Document type	Journal Article
ISSN	1520-5851
ISSN (online)	1520-5851
DOI	10.1021/acs.est.3c06816
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Article ; Online: Ag-CuO/epoxy hybrid nanocomposites as anti-corrosive coating and self-cleaning on copper substrate.

Abdel-Karim, Amal M / Ahmed, Yousra M / El-Masry, Mai M

Scientific reports

2023 Volume 13, Issue 1, Page(s) 19248

Abstract: This study aims to prepare Ag-CuO nanoparticles and assess their efficiency in protecting the copper substrate. The prepared Ag-CuO nanoparticle was characterized using, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning ... ...

Abstract	This study aims to prepare Ag-CuO nanoparticles and assess their efficiency in protecting the copper substrate. The prepared Ag-CuO nanoparticle was characterized using, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope/energy-dispersive X-ray (SEM/EDX), and transmission electron microscope (TEM). The anticorrosion performance of the epoxy coatings containing various weight percentages of Ag-CuO nanoparticles was evaluated in 3.5 wt% NaCl solution using potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques. The results showed that corrosion potential shifted from - 0.211 V for uncoated copper to - 0.120 V for 5.0 wt% Ag-CuO/epoxy hybrid nanocomposite. Electrochemical measurements indicated that the coating 5.0 wt% coating exhibited excellent inhibiting properties with an efficiency of 99.9%. Wettability and mechanical properties were measured for both uncoated and coated copper substrates. The contact angle for 5.0 wt% coating is equal to 104° enhancing the hydrophobic character of the surface. The study clearly establishes that the hybrid composite has a significant potential for protecting the copper substrate.
Language	English
Publishing date	2023-11-07
Publishing country	England
Document type	Journal Article
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-023-46533-x
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Article ; Online: Head and neck mycetoma: Clinical findings, investigations, and predictors for recurrence of the disease in Sudan: A retrospective study.

Omer, Alaa T / Hasabo, Elfatih A / Bashir, Sara N / El Hag, Noha E / Ahmed, Yousra S / Abdelgadir, Istabraq I / Osman, Asma A

PLoS neglected tropical diseases

2022 Volume 16, Issue 10, Page(s) e0010838

Abstract: Introduction: Mycetoma is a unique neglected tropical disease which is found endemic in areas known as the "mycetoma belt". Head and neck mycetoma is a rarity and it has many devastating impacts on patients and communities. In this study, we assessed ... ...

Abstract	Introduction: Mycetoma is a unique neglected tropical disease which is found endemic in areas known as the "mycetoma belt". Head and neck mycetoma is a rarity and it has many devastating impacts on patients and communities. In this study, we assessed clinical findings, investigations, and predictors for recurrence of head and neck mycetoma in Sudan. Methodology: A retrospective study was conducted at Mycetoma Research Center in Khartoum between January 1999 and December 2020 for all patients with head and neck mycetoma. Data were analyzed using R software version 4.0.2. Results: We included 107 patients with head and neck mycetoma. 65.4% were young adult males from mycetoma endemic areas in Sudan, and most of them were students (33.6%). Most of patients (64.4%) had actinomycetoma. Before presenting with head and neck mycetoma, majority (75.7%) had a long duration with mycetoma, and 30.8% had a history of trauma. The commonest invaded site was the parietal region (30.8%). The lesion started gradually in most of the patients (96.3%). 53.3% of the patients had large size lesions with no sweating, regional lymph nodes involvement, or distal vein involvement. CT scan was the most accurate diagnostic tool while 8.4% of patients were diagnosed by clinical examinations only. Laboratory investigations confirmed that 24/45 (44.4%) of actinomycetoma was caused by Streptomyces somaliensis while 13/28 (46.4%) of eumycetoma was caused by Madurella mycetomatis. All patients with recurrence of head and neck mycetoma underwent surgical excision of the lesion (n = 41/41 {100%}, p < 0.001). Conclusion: In head and neck mycetoma, the most common type was actinomycetes in Sudan. Majority had a long course of mycetoma and the commonest causative organism was Streptomyces somaliensis. The treatment outcome was poor and characterized by a low cure rate.
MeSH term(s)	Humans ; Male ; Young Adult ; Madurella ; Mycetoma/diagnosis ; Mycetoma/drug therapy ; Mycetoma/epidemiology ; Mycetoma/microbiology ; Retrospective Studies ; Streptomyces ; Sudan/epidemiology
Language	English
Publishing date	2022-10-17
Publishing country	United States
Document type	Journal Article
ZDB-ID	2429704-5
ISSN	1935-2735 ; 1935-2735
ISSN (online)	1935-2735
ISSN	1935-2735
DOI	10.1371/journal.pntd.0010838
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Article ; Online: Knowledge, attitude and practices regarding COVID-19 and their associated factors in patients with type 2 diabetes attending Abdullah-Khalil diabetes center, Omdurman: A cross-sectional study.

Ahmed, Yousra S / Mohamed, Meirfat I / Hasabo, Elfatih A / Omer, Alaa T / Abdelgadir, Istabraq I / Bashir, Sara N / El Hag, Noha E

Medicine

2022 Volume 101, Issue 52, Page(s) e32561

Abstract: Novel corona virus disease 2019 is the major threat for human life nowadays worldwide. This study aims to assess the knowledge, attitude and practices regarding COVID-19 among patients with type 2 diabetes attending Abdullah Khalil diabetes center ( ... ...

Abstract	Novel corona virus disease 2019 is the major threat for human life nowadays worldwide. This study aims to assess the knowledge, attitude and practices regarding COVID-19 among patients with type 2 diabetes attending Abdullah Khalil diabetes center (Omdurman Teaching Hospital). A facility-based observational descriptive cross-sectional study was carried out between January and February 2021, using non-probability quota sampling technique in Abdullah-Khalil diabetes center via the use of a structured close-ended interview questionnaire. It consisted of 19, 10, and 10 questions pertaining to knowledge, attitude and practices towards COVID-19 respectively. A total of 249 patients with type 2 diabetes were included. Of them, 132 (53.0%) were females and the majority (53.0%) aged between 41 and 60 years old. Concerning their education and marital status, 70 (28.1%) were primary school level and 208 (83.5%) were married. 89.6% of participants reported mass media as main source of information regarding COVID-19. Patients with type 2 diabetes attending Abdullah-Khalil diabetes center have good knowledge, positive attitude and good prevention practices towards COVID-19. Most respondents had good knowledge, positive attitude and good practices as 78.7%, 97.6%, and 69.9%, respectively. Educational level and source of information showed statistically significant association with the knowledge, attitude. However, the practice showed only statistical association with the mass media as a source of information (P = .006).
MeSH term(s)	Female ; Humans ; Adult ; Middle Aged ; Male ; COVID-19 ; Diabetes Mellitus, Type 2/therapy ; Cross-Sectional Studies ; Health Knowledge, Attitudes, Practice ; Hospitals, Teaching
Language	English
Publishing date	2022-12-12
Publishing country	United States
Document type	Journal Article
ZDB-ID	80184-7
ISSN	1536-5964 ; 0025-7974
ISSN (online)	1536-5964
ISSN	0025-7974
DOI	10.1097/MD.0000000000032561
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Article ; Online: Engineering of Streptomyces lividans for heterologous expression of secondary metabolite gene clusters.

Ahmed, Yousra / Rebets, Yuriy / Estévez, Marta Rodríguez / Zapp, Josef / Myronovskyi, Maksym / Luzhetskyy, Andriy

Microbial cell factories

2020 Volume 19, Issue 1, Page(s) 5

Abstract: Background: Heterologous expression of secondary metabolite gene clusters is used to achieve increased production of desired compounds, activate cryptic gene clusters, manipulate clusters from genetically unamenable strains, obtain natural products from ...

Abstract	Background: Heterologous expression of secondary metabolite gene clusters is used to achieve increased production of desired compounds, activate cryptic gene clusters, manipulate clusters from genetically unamenable strains, obtain natural products from uncultivable species, create new unnatural pathways, etc. Several Streptomyces species are genetically engineered for use as hosts for heterologous expression of gene clusters. S. lividans TK24 is one of the most studied and genetically tractable actinobacteria, which remain untapped. It was therefore important to generate S. lividans chassis strains with clean metabolic backgrounds. Results: In this study, we generated a set of S. lividans chassis strains by deleting endogenous gene clusters and introducing additional φC31 attB loci for site-specific integration of foreign DNA. In addition to the simplified metabolic background, the engineered S. lividans strains had better growth characteristics than the parental strain in liquid production medium. The utility of the developed strains was validated by expressing four secondary metabolite gene clusters responsible for the production of different classes of natural products. Engineered strains were found to be superior to the parental strain in production of heterologous natural products. Furthermore, S. lividans-based strains were better producers of amino acid-based natural products than other tested common hosts. Expression of a Streptomyces albus subsp. chlorinus NRRL B-24108 genomic library in the modified S. lividans ΔYA9 and S. albus Del14 strains resulted in the production of 7 potentially new compounds, only one of which was produced in both strains. Conclusion: The constructed S. lividans-based strains are a great complement to the panel of heterologous hosts for actinobacterial secondary metabolite gene expression. The expansion of the number of such engineered strains will contribute to an increased success rate in isolation of new natural products originating from the expression of genomic and metagenomic libraries, thus raising the chance to obtain novel biologically active compounds.
MeSH term(s)	Actinobacteria/genetics ; Actinobacteria/metabolism ; Anti-Bacterial Agents/biosynthesis ; Anti-Bacterial Agents/chemistry ; Bacteriocins/biosynthesis ; Bacteriocins/chemistry ; Biological Products/chemistry ; Biological Products/metabolism ; Cloning, Molecular ; Genetic Engineering/methods ; Multigene Family ; Peptides, Cyclic/biosynthesis ; Peptides, Cyclic/chemistry ; Secondary Metabolism/genetics ; Streptomyces lividans/genetics ; Streptomyces lividans/metabolism ; Tunicamycin/biosynthesis ; Tunicamycin/chemistry
Chemical Substances	Anti-Bacterial Agents ; Bacteriocins ; Biological Products ; Peptides, Cyclic ; Tunicamycin (11089-65-9) ; cinnamycin (1405-39-6)
Language	English
Publishing date	2020-01-09
Publishing country	England
Document type	Journal Article
ISSN	1475-2859
ISSN (online)	1475-2859
DOI	10.1186/s12934-020-1277-8
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Article ; Online: Ray Tracing for Fluence Rate Simulations in Ultraviolet Photoreactors.

Ahmed, Yousra M / Jongewaard, Mark / Li, Mengkai / Blatchley, Ernest R

Environmental science & technology

2018 Volume 52, Issue 8, Page(s) 4738–4745

Abstract: The performance of photochemical reactors is governed by the spatial distribution of radiant energy within the irradiated region of the reactor. Ray tracing has been widely used for simulation of lighting systems. The central hypothesis of this work was ... ...

Abstract	The performance of photochemical reactors is governed by the spatial distribution of radiant energy within the irradiated region of the reactor. Ray tracing has been widely used for simulation of lighting systems. The central hypothesis of this work was that ray tracing can provide accurate simulations of fluence rate fields within ultraviolet (UV) photoreactors by accounting for the physical and optical phenomena that will govern fluence rate fields in UV photoreactors. Ray tracing works by simulating the behavior of a large population of rays emanating from a radiation source to describe the spatial distribution of radiant energy (i.e., fluence rate) within a system. In this study, fluence rate calculations were performed using commercial ray tracing software for three basic UV reactors, each with a single low-pressure Hg lamp. Fluence rate calculations in the ray tracing program were based on the formal definition of fluence rate, calculated as the incident radiant power from all directions on a small spherical receptor, divided by the cross-sectional area of that sphere. The results of this study demonstrate that ray tracing can provide predictions of fluence rate in UV radiative systems that are close to experimental measurements and the predictions of other numerical methods.
MeSH term(s)	Lighting ; Ultraviolet Rays
Language	English
Publishing date	2018-04-04
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	1520-5851
ISSN (online)	1520-5851
DOI	10.1021/acs.est.7b06250
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Book ; Online ; Thesis: Engineering of Streptomyces albus J1074 and Streptomyces lividans TK24 for natural products production

Ahmed, Yousra [Verfasser] / Luzhetskyy, Andriy [Akademischer Betreuer]

2019

Author's details	Yousra Ahmed ; Betreuer: Andriy Luzhetskyy
Keywords	Biowissenschaften, Biologie ; Life Science, Biology
Subject code	sg570
Language	English
Publisher	Saarländische Universitäts- und Landesbibliothek
Publishing place	Saarbrücken
Document type	Book ; Online ; Thesis
Database	Digital theses on the web

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Article ; Online: Robotic surgery for colorectal cancer in the Octogenarians.

Westrich, Gal / Mykoniatis, Ioannis / Stefan, Samuel / Siddiqi, Najaf / Ahmed, Yousra / Cross, Matthew / Nissan, Aviram / Khan, Jim S

The international journal of medical robotics + computer assisted surgery : MRCAS

2021 Volume 17, Issue 4, Page(s) e2268

Abstract: Background: We evaluated the short-term outcomes of robotic colorectal cancer surgery in octogenarian patients, focussing on postoperative morbidity and survival.: Methods: All patients ≥80 years in a prospective colorectal cancer database undergoing ...

Abstract	Background: We evaluated the short-term outcomes of robotic colorectal cancer surgery in octogenarian patients, focussing on postoperative morbidity and survival. Methods: All patients ≥80 years in a prospective colorectal cancer database undergoing robotic curative colorectal cancer resection were included. Patient demographics, intraoperative findings, postoperative and oncological outcomes were recorded. Patients were further subdivided into two groups named: old (OG 80-85 years) and very old (VOG ≥ 86 years). Results: Fifty-eight consecutive patients were included (median age, 83 years; male, 53.4%; median BMI, 26.5). Median total operative time was 230 min, median blood loss 20 ml, median length of stay 7 days. Major complications were seen in 12% of patients; and the 90-day mortality rate was 1.7%. Complete R0 resection achieved in 93% of cases, average lymph node harvest was 22. Overall and disease-free survival was 81% and 87.3%, respectively (median follow-up 24.5 months). We noticed a trend towards more advanced lesion staging in the VOG, but only N2 stage was significant (p = 0.03). There was a statistically significant difference in overall survival in favour of the OG (p = 0.024). Conclusions: Robotic surgery is feasible in octogenarian patients undergoing curative colorectal cancer resection and is associated with good post-operative outcomes and overall survival.
MeSH term(s)	Aged, 80 and over ; Colorectal Neoplasms/surgery ; Female ; Humans ; Laparoscopy ; Male ; Operative Time ; Postoperative Complications ; Prospective Studies ; Robotic Surgical Procedures ; Treatment Outcome
Language	English
Publishing date	2021-05-21
Publishing country	England
Document type	Journal Article
ZDB-ID	2151860-9
ISSN	1478-596X ; 1478-5951
ISSN (online)	1478-596X
ISSN	1478-5951
DOI	10.1002/rcs.2268
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Article ; Online: Identification of butenolide regulatory system controlling secondary metabolism in Streptomyces albus J1074.

Ahmed, Yousra / Rebets, Yuriy / Tokovenko, Bogdan / Brötz, Elke / Luzhetskyy, Andriy

Scientific reports

2017 Volume 7, Issue 1, Page(s) 9784

Abstract: A large majority of genome-encrypted chemical diversity in actinobacteria remains to be discovered, which is related to the low level of secondary metabolism genes expression. Here, we report the application of a reporter-guided screening strategy to ... ...

Abstract	A large majority of genome-encrypted chemical diversity in actinobacteria remains to be discovered, which is related to the low level of secondary metabolism genes expression. Here, we report the application of a reporter-guided screening strategy to activate cryptic polycyclic tetramate macrolactam gene clusters in Streptomyces albus J1074. The analysis of the S. albus transcriptome revealed an overall low level of secondary metabolism genes transcription. Combined with transposon mutagenesis, reporter-guided screening resulted in the selection of two S. albus strains with altered secondary metabolites production. Transposon insertion in the most prominent strain, S. albus ATGSal2P2::TN14, was mapped to the XNR_3174 gene encoding an unclassified transcriptional regulator. The mutant strain was found to produce the avenolide-like compound butenolide 4. The deletion of the gene encoding a putative acyl-CoA oxidase, an orthologue of the Streptomyces avermitilis avenolide biosynthesis enzyme, in the S. albus XNR_3174 mutant caused silencing of secondary metabolism. The homologues of XNR_3174 and the butenolide biosynthesis genes were found in the genomes of multiple Streptomyces species. This result leads us to believe that the discovered regulatory elements comprise a new condition-dependent system that controls secondary metabolism in actinobacteria and can be manipulated to activate cryptic biosynthetic pathways.
MeSH term(s)	4-Butyrolactone/analogs & derivatives ; 4-Butyrolactone/chemistry ; 4-Butyrolactone/metabolism ; Chromatography, Liquid ; Gene Expression Regulation, Fungal ; Genes, Fungal ; Hormones/metabolism ; Mass Spectrometry ; Multigene Family ; Mutation ; Secondary Metabolism/genetics ; Streptomyces/genetics ; Streptomyces/metabolism ; Transcription, Genetic
Chemical Substances	Hormones ; butenolide (8KXK25H388) ; 4-Butyrolactone (OL659KIY4X)
Language	English
Publishing date	2017-08-29
Publishing country	England
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-017-10316-y
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Article: Ray Tracing for Fluence Rate Simulations in Ultraviolet Photoreactors

Ahmed, Yousra M / Ernest R. Blatchley / Mark Jongewaard / Mengkai Li

Environmental science & technology. 2018 Mar. 29, v. 52, no. 8

2018

Abstract	The performance of photochemical reactors is governed by the spatial distribution of radiant energy within the irradiated region of the reactor. Ray tracing has been widely used for simulation of lighting systems. The central hypothesis of this work was that ray tracing can provide accurate simulations of fluence rate fields within ultraviolet (UV) photoreactors by accounting for the physical and optical phenomena that will govern fluence rate fields in UV photoreactors. Ray tracing works by simulating the behavior of a large population of rays emanating from a radiation source to describe the spatial distribution of radiant energy (i.e., fluence rate) within a system. In this study, fluence rate calculations were performed using commercial ray tracing software for three basic UV reactors, each with a single low-pressure Hg lamp. Fluence rate calculations in the ray tracing program were based on the formal definition of fluence rate, calculated as the incident radiant power from all directions on a small spherical receptor, divided by the cross-sectional area of that sphere. The results of this study demonstrate that ray tracing can provide predictions of fluence rate in UV radiative systems that are close to experimental measurements and the predictions of other numerical methods.
Keywords	computer software ; environmental science ; irradiation ; mercury ; photochemistry ; prediction ; radiant energy
Language	English
Dates of publication	2018-0329
Size	p. 4738-4745.
Publishing place	American Chemical Society
Document type	Article
ISSN	1520-5851
DOI	10.1021/acs.est.7b06250
Database	NAL-Catalogue (AGRICOLA)

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