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The effect of prerolling before artificial aging on the mechanical properties of the Al–Zn–Mg–Cu–Sc–Zr–Mn alloy with 12.4 wt% Zn (Zn/Mg ratio >1.3 at.%) is studied. The alloy sheets are prepared via casting, homogenization, hot rolling, and solution treatment. The sheets are further cold rolled to reduce their thicknesses by 0%–50% before being artificially aged. Yield strength, ultimate tensile strength, and elongation are increased from 648 to 697 MPa, from 662 to 712 MPa, and from 2.2% to 4.4% by prerolling up to 30%, and prerolling again by 50% reduces both the strength and elongation. Changes in the microstructural features, such as grain morphology, dislocation density, and defect characteristics, are attributed to the variations in the strength and elongation of the alloy. Work hardening during prerolling is responsible for the increase in strength, while pore closure and shear band formation induced by prerolling either increase or decrease the elongation. Furthermore, precipitation kinetics are accelerated by applying prerolling, which facilitates a faster aging response, lesser processing time to reach the peak hardness, and better mechanical properties.

Poultry can be a sustainable source of eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) through the bioconversion of dietary alpha-linolenic acid (ALA, 18:3n-3). However, this process is currently limited by the high n-6/n-3 ratio in poultry diets affecting the competition between n-6 and n-3 fatty acids (FA) for the same biosynthetic enzymes, and the rate-limiting Δ6 desaturase which act at both, the first and final steps of DHA synthesis pathway. Echium plantagineum oil (EO) is an unusual source of stearidonic acid (SDA, 18:4n-3) which bypasses the first Δ6 desaturase step potentially increasing n-3 long-chain polyunsaturated fatty acids (LC-PUFA) synthesis. To explore this hypothesis, 60 Canarian male chickens at 18 weeks of age were divided into three groups and fed diets differing only in their FA formulation: soy oil (SO) rich in linoleic acid (LA, 18:2n-6); linseed oil (LO) rich in ALA; and EO, a balanced LA/ALA oil also rich in SDA and γ-linolenic acid (GLA, 18:3n-6). The dietary treatments did not affect the total lipid (TL) content (p>0.05) and did not substantially vary the lipid class (LC) profiles in the brain, liver, intestine, and muscle tissues. However, the inclusion of LO and EO equally increased n-3 polyunsaturated fatty acids (PUFA) levels in the brain, liver, and intestine compared to animals fed with SO (p

The mechanical properties, texture transformation, and mechanism of Al–Cu–Mn alloy during annealing were studied using three-dimensional orientation distribution function (ODF), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM). The results showed that the increase in yield strength after annealing at 200 °C is due to the decrease in the proportion of P and M textures and the increase in the proportion of Goss texture. The increase in the change rate of mechanical properties observed during annealing at 250 and 350 °C can be attributed to the higher proportion of M and P textures and the reduced proportion of Goss textures. Among them, the proportion of M texture increased significantly, and the Goss texture decreased significantly after annealing at 350 °C. This is because the structural energy density (Ev) value of the Goss texture is higher than that of the M texture at 250 °C and 350 °C. The Goss texture is in an unstable state of high energy order. The deformed Goss texture is unstable at high temperatures, leading to conversion into M and other textures. The EBSD and TEM analysis revealed that the hardness is mainly related to the change in dislocation density. When the annealing temperature is increased from 250 to 350 °C, the hardness is significantly reduced from 62 HV to 52 HV, and the dislocation density is reduced from 4.0 × 1014 ρ/m−2 to 2.4 × 1014 ρ/m−2.

Bifilms have been proposed to be critical for forming casting defects. The reduced pressure test (RPT) and bifilm index (BI) have been widely studied and used in industry for melt quality assessment. However, the BI remains challenged in predicting the mechanical properties. This work investigated the usage of RPT for elongation prediction by analyzing the melt in two foundries. The results showed that the BI could be valid when the bifilms exist as fully inflated pores. In reality, bifilms present as pores with various morphology and distribution, generating local stress concentrations under tension. Consequently, the parameter areaeff, which considers the pores’ morphology and distribution, was proposed, and the resultant f eff showed a good correlation with the elongation of the castings. These results guide the foundry to predict the elongation of the final castings and give directions for further research on the bifilm defects.

Steel bars are part and parcel of reinforced concrete used in the construction projects, ranging from single family houses to super tall buildings and long span bridges. Maintaining the quality of the steel bars has always been challenging especially in developing countries. Low quality steel bars result in serviceability issues and reduce useful life of structures. This research work is focused on examining and investigating some basic facts about the quality of the steel bars produced in Pakistan. Pakistan being 5th most populous country in the world has huge consumption of steel. Laboratory testing data of steel bars are statistically analysed to have an insight in to the quality of bars. These steel bars were tested over a period of two years, which belong to several real-life projects. Properties like weight per unit length, yield strength, ultimate strength and percentage elongation were mainly analysed. Findings show that out of the stock of 4782 bars, 17.4 % failed to meet the minimum requirements provided by American Society of Testing and Materials (ASTM A615). Quality of grade 60 bars was found better than those of grade 40.

الملخص: أهداف البحث: يستخدم سيليكون الوجه والفكين لاستعادة التشوهات الناتجة عن أسباب خلقية أو مكتسبة. ومع ذلك، فإن جودة السيليكون بعيدة كل البعد عن المثالية. تهدف هذه الدراسة إلى تقييم تأثير ألياف السليلوز النانوية (ذات قطر نانومتري والطول 2-5 ميكرومتر) بالإضافة إلى الخصائص الفيزيائية والميكانيكية لسيليكون اللدائن المرنة للوجه والفكين. طريقة البحث: تم استخدام نسبتين من الوزن (0,5% و 1%). تم إنشاء 180عينة وتصنيفها إلى مجموعة ضابطة ومجموعتين تجريبيتين. تم تقسيم كل مجموعة إلى ست مجموعات فرعية. لكل مجموعة فرعية، تم استخدام 10 عينات لكل اختبار (قوة التمزق، قياس صلابة المواد، قوة الشد، نسبة الاستطالة، خشونة السطح، ثبات اللون). تم فحص العينات بواسطة المجهر الالكتروني الماسح والتحليل الطيفي للأشعه تحت الحمراء لتحويل ''فورييه” والانبعاثات الميدانية. النتائج: أظهرت المجموعات 0,5% زيادة معنوية عالية في مقاومة التمزق ونسبة الاستطالة وصلابة المواد وخشونة السطح وارتفاع كبير في اختبار مقاومة الشد مقارنة بمجموعة التحكم. ومع ذلك، لم يختلف ثبات اللون بشكل كبير بين المجموعتين. بينما أظهرت المجموعة التجريبية 1%زيادة معنوية في صلابة المواد،مقاومة التمزق، ثبات اللون، خشونة السطح وانخفاض غير معنوي في مقاومة الشد وقيم الاستطالة المئوية بالمقارنة مع مجموعة التحكم العادية. أظهرت صور المجهر الالكتروني الماسح توزيع جيد لألياف السليلوز النانوية مع زيادة ظهور التكتلات عند التراكيز العالية للألياف النانوية وكما أظهر التحليل الطيفي للأشعه تحت الحمراء الى تفاعل ألياف السليلوز النانوية مع السيلكون من خلال مجموعات الهدروكسيل الوظيفيه السطحية. الاستنتاجات: أدت إضافة 0,5% بالوزن من ألياف السليلوز النانوية إلى سيليكون الوجه والفكين إلى زيادة قوة الشد الميكانيكية للمادة، وقوة التمزق، ونسبة الاستطالة والصلابة طالما بقيت ضمن النطاق المقبول في الاستخدام السريري. زادت خشونة السطح بالتناسب المباشر مع كمية الألياف النانوية المضافة. علاوة على ذلك، فإن إضافة 0,5% بالوزن من ألياف السليلوز النانوية إلى بوليمر السيليكون له تأثير ضئيل على ثبات اللون. Abstract: Objectives: Maxillofacial silicone is used to restore abnormalities due to congenital or acquired causes. However, the quality of silicone is far from ideal. This study was aimed at assessing the influence of the addition of cellulose nanofibers (CNFs; several nanometers in diameter and 2–5 μm long) on the physical and mechanical characteristics of maxillofacial silicone elastomers. Methods: Two CNF weight percentages (0.5% and 1%) were tested, and 180 specimens were divided into one control and two experimental groups. Each group was subdivided into six subgroups. In each subgroup, ten specimens subjected to each of the following tests: tearing strength, Shore-A hardness, tensile strength, elongation percentage, surface roughness, and color stability. The samples were additionally analyzed with Fourier transform infrared spectroscopy (FTIR) and field emission scanning electronic microscopy (FESEM). Results: The 0.5% CNF group, compared with the control group, exhibited highly significantly greater tearing strength, elongation percentage, hardness Shore-A, and surface roughness, and substantially greater tensile strength. However, color stability did not significantly differ between groups.The 1% CNF group showed significantly greater Shore-A hardness, tear strength, color stability, and surface roughness, and insignificantly lower tensile strength and percentage elongating values, than the control group. FESEM imaging revealed good CNF dispersion. The FTIR spectra indicated that CNFs interacted with silicone through surface functional hydroxyl groups. Conclusion: Addition of 0.5 wt. % CNF to silicone elastomers increased the material's mechanical tensile strength, tear strength, elongation percentage, and hardness as long as it stayed within the acceptable range for clinical use. Surface roughness increased in direct proportion to the amount of nanofibers added. Moreover, addition of 0.5 wt. % CNF to silicone polymers had insignificant effects on color stability.

Population expansion is causing an increase in dependence on plastic materials. The worst aspects of conventional plastics were their inability to biodegrade, their poor capacity to transmit water vapor, and their production of greenhouse gases. Usages of bioplastics are necessary for the advancement of a green economy and environment in order to eradicate these drawbacks of traditional plastics. In this study, reinforced bioplastic film was produced from anchote (Coccinia Abyssinica) starch and enset (Ensete Ventricosum) fiber. Starch from anchote was extracted and its properties were characterized via adequate techniques. The maximum carbohydrate content (86.26 ± 0.25%w/w) of anchote starch indicates that it is suitable feedstock for plastic film production. In addition, extracted starch was characterized by SEM, FTIR, TGA and XRD. The reinforcing material enset fiber was extracted and characterized by FTIR and XRD. The results of both feedstock materials exhibited the good characteristics and viability for bioplastic film production. Enset fiber loadings used were 0 %, 4 %, 8 %, 12 % and 16 % w/w in starch basis. Tensile strength, elongation, thickness, moisture content, transparency, solubility and density of produced bioplastic were determined. Tensile force grew and elongation reduced as fiber loading rose up to 8 %. The tensile strength gradually declined with increasing fiber loading. Additionally, the created bioplastic film's groups of functions and chemical bonds were examined. In comparison to unreinforced plastic film, the results showed that the reinforced bioplastic film used in this study was an excellent and effective product.

The effect of Er and Si on the evolution of precipitates in Al–Cu–Mg alloys during elevated temperature exposure was investigated. The Er segregation in θ′-Al2Cu precipitates and Si/Mg co-segregation at the interfaces of θ'/Al matrix are experimentally observed in Al–Cu–Mg–Si–Er alloy, which finally contributes to the heat resistance of the Al–Cu–Mg–Si–Er alloy. Si enhances formation of the Q″ phases as nucleation sites for the θ′ phases, resulting in a refined distribution of θ′ phases. Al–Cu–Mg alloy with high strength as well as high thermal stability is obtained by co-adding Er and Si. The high-temperature yield strength (YS) of Al–Cu–Mg–Si–Er alloy at 225 °C are increased by 37 MPa compared with that of Al–Cu–Mg alloy. Simultaneously, the addition of Er significantly increases the elongation of Al–Cu–Mg–Si–Er alloy.

Stenting is used to achieve artery patency, and the Supera stent, a self-expanding interwoven nitinol stent, has produced good clinical outcomes. A 70-year-old woman with peripheral artery disease had experienced intermittent claudication (Fontaine stage IIb). Endovascular treatment was performed for a chronic total occlusion TransAtlantic InterSociety Consensus class II type B lesion. A Supera stent (Abbott Vascular, Santa Clara, CA) was used. However, it had become severely elongated to the proximal end in the superficial femoral artery and was removed using a balloon inserted from the side and trapped to the guide sheath with the distal end of the stent outside the sheath. After this bailout, an alternate stent could be placed through an antegrade approach to the contralateral common femoral artery.

In this study, we investigate the microstructures and mechanical properties of quenching and partitioning (Q&P) steels prepared with hot-rolled (HR) and cold-rolled (CR) sheets at different annealing temperatures (partial austenitisation). The ferrite and retained austenite are present in laths and blocks in HR-Q&P samples but are mainly blocky in CR-Q&P samples. Compared with CR-Q&P, the HR-Q&P samples have higher content of retained austenite, better elongation and higher product of strength and elongation (PSE). The lath-shaped retained austenite in HR-Q&P samples with a higher ratio of surface to volume is conducive to homogenization of carbon in austenite grains, thus improving the thermal stability and content of retained austenite. The lath-shaped retained austenite transforms into martensite obviously until the strain exceeds 5% and exhibits higher mechanical stability than coarse blocky retained austenite. When annealed at 810 °C, HR-Q&P and CR-Q&P samples present best PSEs. Indeed, the PSE of HR-810°C-Q&P sample is 62.8% higher than that of CR%-810°C-Q&P. The better elongation and higher PSE possessed by HR-810°C-Q&P sample are linked with the higher content of retained austenite and the presence of two kinds of retained austenite with different mechanical stability. The retained austenite with different mechanical stability in HR-810°C-Q&P sample, contributes to continuous transformation during tensile deformation, thereby improving the elongation. Meanwhile, the lath-shaped structures can delay the formation of voids and microcracks, thereby improving the elongation.

β-1,3-Glucans form the major carbohydrate component of fungal cell walls, playing a vital role in cell viability, stress response, virulence, and even healthy functions such as immuno-enhancement. The elongation and branching of β-1,3-glucans is a mystery. More evidence proved the β-1, 3-glucantransferases belonging to GH72 or GH17 family to branch and remodel the synthesized linear β-1, 3-glucan chain by cleaving its internal β-1, 3-linkage and transfer the cleaved fragment to the nonreducing end of another β-1, 3-glucan acceptor. The present review summarized the comprehensive advances of β-1, 3-glucantransferases including their structures such as catalytic and non-catalytic protein domains, catalytic mechanisms and roles in cell wall formation, cell separation and cell viability to provide the references for understanding and guiding the biosynthesis and production regulation of functional β-1, 3-glucans with high-branched or elongated structures., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The accurate and efficient biogenesis of RNA by cellular RNA polymerase (RNAP) requires accessory factors that regulate the initiation, elongation, and termination of transcription. Of the many discovered to date, the elongation regulator NusG-Spt5 is the only universally conserved transcription factor. With orthologs and paralogs found in all three domains of life, this ubiquity underscores their ancient and essential regulatory functions. NusG-Spt5 proteins evolved to maintain a similar binding interface to RNAP through contacts of the NusG N-terminal domain (NGN) that bridge the main DNA-binding cleft. We propose that varying strength of these contacts, modulated by tethering interactions, either decrease transcriptional pausing by smoothing the rugged thermodynamic landscape of transcript elongation or enhance pausing, depending on which conformation of RNAP is stabilized by NGN contacts. NusG-Spt5 contains one (in bacteria and archaea) or more (in eukaryotes) C-terminal domains that use a KOW fold to contact diverse targets, tether the NGN, and control RNA biogenesis. Recent work highlights these diverse functions in different organisms. Some bacteria contain multiple specialized NusG paralogs that regulate subsets of operons via sequence-specific targeting, controlling production of antibiotics, toxins, or capsule proteins. Despite their common origin, NusG orthologs can differ in their target selection, interacting partners, and effects on RNA synthesis. We describe the current understanding of NusG-Spt5 structure, interactions with RNAP and other regulators, and cellular functions including significant recent progress from genome-wide analyses, single-molecule visualization, and cryo-EM. The recent findings highlight the remarkable diversity of function among these structurally conserved proteins., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The effect of friction stir processing (FSP) on the microstructure evolution and mechanical properties of as-cast Mg–Zn–Ca (Mg-1.2wt%Zn-0.1wt%Ca) alloy was investigated. The result shows that the average grain size of the stir zone is greatly refined from ∼170 μm to ∼13 μm. Moreover, a basal texture is formed in the stir zone, and the c-axis of the grain is tilted to the normal direction about 42.6° away from the processing direction. Although the tensile strength has little improvement compared to the as-cast alloy, the elongation is increased from 24.6% to 45.4%. The excellent room-temperature ductility of the FSP alloy is mainly attributed to the fine grain size and the preferential orientation of the grains in the stir zone. The Schmid factor up to 0.44 means that basal slip is beneficial to be activated, resulting in a high elongation.

The solidification rate of materials affects the properties of the cast product and the pouring temperature also influences the freezing conditions of cast-metal alloys. The propose of this study is to evaluate the tensile strength of cast samples by using five variations of pouring temperatures through permanent molds by a gravity casting process. The results showed that the tensile strength maximum was 443 MPa at 1210 °C, the freezing range affected the tensile properties of cast samples.

Synucleinopathies like Parkinson's disease are neurodegenerative diseases which are associated with the deposition of fibrillar aggregates of the endogenous protein α-synuclein (α-syn). The inhibition of the elongation of α-syn fibrils is of great scientific interest and an option in the design of therapeutic strategies. Previously, we developed a disulfide-containing mutant of α-syn, called CC48, which inhibits fibril elongation by blocking of fibril ends. Surprisingly, wildtype (WT) α-syn molecules supported the blocked state, and a fusion of CC48 with WT α-syn, denoted WT-CC48, exhibited increased inhibitory potential. Here, we studied which regions of WT-CC48 are responsible for the strong inhibitory effect. To this end, we investigated a set of truncated versions of WT-CC48 by kinetic elongation assays, density gradient centrifugation, and atomic force microscopy. We show that in both the WT and the CC48 part of the fusion construct the hairpin region (residue 32–60) and NAC region (61–95), but not N- and C-terminal regions, are required for strong inhibition of fibril elongation. The required regions correspond to the segments forming the β-sheet core of α-syn fibrils. As α-syn fibrils typically consist of two protofilaments, the dimeric construct WT-CC48 provides the critical regions sufficient to cover the full β-sheetcore interface exposed at the fibril end, which can explain its high inhibitory efficiency. We suggest a mechanistic model of CC48-mediated inhibition of fibril elongation in which CC48 and WT α-syn cooperatively form an oligomer-like cap at the amyloid fibril end.

The hardness test is considered one of the easiest mechanical tests in terms of preparing its specimens, as it does not need machining, unlike the tensile test that needs special machining and preparation. Six groups of Aluminium-Silicon alloys have been produced with different Si contents at different modifier and grains refiner. The correlations between the hardness with yield strength, ultimate tensile strength, and elongation for these groups were investigated by the regression analysis and an artificial neural network model.The measured Brinell hardness, yield strength, ultimate tensile strength, and elongation for these groups ranged between 48 - 98 HB, 49 - 103 MPa, 90 - 202 MPa, and 3 - 10.4%, respectively. The best results were obtained for a mixture of modifier (Na2SiF6) and refiner (Al-3Ti-3B). The results indicated that the trainable cascade-forward back-propagation algorithm has the best forecast accuracy for determining the percentage of Si in the produced alloys based on material properties or predicting the properties of these alloys based on the Si percentage.

The era of the Internet of Things (IoT) is becoming a reality, and the display equipment is at its center. The display device is the window that connects the IoT and humans, and is evolving into various form factors convenient to human use, such as foldable mobile phone, flexible wearable device, paper-like display, and rollable TV. Even though transparent flexible electrodes and substrates have been developed, their assembly remains a challenge. Therefore, the importance of optically clear acrylic pressure-sensitive adhesives (PSAs) that ensure device integrity by easily stretched and mitigating the stress during repeated stretching and bending process is being emphasized. In this study, elongation and recovery features were identifiable as key flexible properties of PSAs. These properties were estimated by measuring shear strain and strain recovery using a universal testing machine and by dynamic mechanical analytics respectively. Compared to conventional UV metal halide curing, a newly introduced ultraviolet light-emitting diode (UV LED) curing process resulted in different PSA property variables, namely UV exposure intensity and UV exposure time. Fully cured acrylic PSA realized under UV LED exposure level 30 for 8 s demonstrated the highest shear strain with excellent strain recovery of ~23,500% and 94% respectively. Under these conditions, effective material adhesion performance was achieved while retaining optical transparency and thus fulfilling the dual property requirement for non-opaque material adhesiveness necessary for use in flexible displays.

The search to improve the characteristics of biomaterials obtained from natural biopolymers such as starch has led to the use of mixtures of various polymers with plasticizing agents such as glycerol and sorbitol. In this research, the effect of concentration (10, 20, 30, 40 and 50% starch basis) and type of plasticizer (glycerol and sorbitol) on water solubility (WS), total color difference (ΔE), mechanical properties and water vapor permeability (WVP) of films based on sweet potato starch was evaluated. The mechanical properties were determined by the Puncture Strength method, WVP and WS were performed using gravimetric methods, ΔE was determined by a colorimeter. The results showed an inverse relationship between the puncture resistance and ΔE of the films with the concentration of the plasticizers. However, an increase in plasticizer concentration led to an increase in the percentage of elongation, WS, and WVP of sweet potato starch films. The highest values for percentage elongation and WVP were found in films plasticized with glycerol. Sweet potato starch can be used for the development of film for edible candy wrappers and edible coatings fresh fruit and vegetables.

Samples of AA5052 aluminum alloy were severely deformed up to 6 passes using equal channel angular pressing (ECAP). It was found that the yield strength (YS) and ultimate tensile strength (UTS) of the alloy significantly increased while the uniform elongation (eu) and elongation to failure (ef) reduced which was resulted from reducing the work hardenability. Reduction of elongation caused a significant drop in toughness, defined as the area under the stress-strain curve. The results showed that the amount of toughness continued to decrease with increasing number of passes. However, after holding the ECAP processed samples at room temperature for one year their YS reduced remarkably while the UTS remained unchanged, their work hardenability was improved and led to improvement in eu and ef. This led to a significant increase in toughness.

Ribosomal protein 25 (RPS25) has been related to male fertility diseases in humans. However, the role of RPS25 in spermatogenesis has yet to be well understood. RpS25 is evolutionarily highly conserved from flies to humans through sequence alignment and phylogenetic tree construction. In this study, we found that RpS25 plays a critical role in Drosophila spermatogenesis and its knockdown leads to male sterility. Examination of each stage of spermatogenesis from RpS25-knockdown flies showed that RpS25 was not required for initial germline cell divisions, but was required for spermatid elongation and individualization. In RpS25-knockdown testes, the average length of cyst elongation was shortened, the spermatid nuclei bundling was disrupted, and the assembly of individualization complex from actin cones failed, resulting in the failure of mature sperm production. Our data revealed an essential role of RpS25 during Drosophila spermatogenesis through regulating spermatid elongation and individualization., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Rupture of the Achilles tendon may result in reduced functional activity and reduced plantar flexion strength. These changes may arise from elongation of the Achilles tendon. An observational study was performed to quantify the Achilles tendon resting angle (ATRA) in patients following Achilles tendon rupture, surgical repair, and rehabilitation, respectively. Methods: Between May 2012 and January 2013, 26 consecutive patients (17 men), with a mean (standard deviation, SD) age of 42 (8) years were included and evaluated following injury, repair, and at 6 weeks, 3 months, 6 months, 9 months, and 12 months, respectively (rehabilitation period). The outcome was measured using the ATRA, Achilles tendon total rupture score (ATRS), and heel-rise test. Results: Following rupture, the mean (SD) absolute ATRA was 55 (8)° for the injured side compared with 43 (7)° (p

Purpose: The Euclid Emerald lens designs for orthokeratology have been available in global markets for over 20 years and is used extensively by clinicians for slowing myopia progression in children. This paper comprehensively reviews data from published studies of the efficacy of this lens., Methods: A comprehensive systematic search was performed in March 2023 using Medline with the following search terms: orthokeratology AND myopi* AND (axial or elong*) NOT (review or meta)., Results: The original search identified 189 articles, of which 140 reported axial elongation. Of those, 49 reported data on the Euclid Emerald design. Unique axial elongation data could be extracted from 37 papers-14 of which included an untreated control group. Among these, the mean 12-month efficacy-the difference in axial elongation between orthokeratology wearers and controls-was 0.18 mm (range: 0.05-0.29 mm), and the mean 24-month efficacy was 0.28 mm (range: 0.17-0.38 mm). The orthokeratology wearers in 23 studies without an untreated comparison group showed similar axial elongation to those in the 14 studies with a control group. For example, the mean 12-month axial elongation for the studies with controls was 0.20 ± 0.06 mm compared with 0.20 ± 0.07 mm for the studies without controls., Conclusions: This extensive body of literature on a single device for myopia control is unique and demonstrates the efficacy of this design in slowing axial elongation in myopic children., Competing Interests: Declaration of Competing Interest Mark Bullimore is a consultant for Alcon Research, Bruno Vision Care, CooperVision, EssilorLuxottica, Euclid Systems, Eyenovia, Genentech, Johnson & Johnson Vision, Lentechs, Novartis, Oculus, and Vyluma. He is owner of Ridgevue Publishing LLC and Ridgevue Vision LLC. Maria Liu is a consultant for CooperVision, Euclid Systems, Essilor China, Paragon Vision Sciences., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The primary products of de novo lipogenesis (DNL) are saturated fatty acids, which confer adverse cellular effects. Human adipocytes differentiated with no exogenous fat accumulated triacylglycerol (TG) in lipid droplets and differentiated normally. TG composition showed the products of DNL (saturated fatty acids from 12:0 to 18:0) together with unsaturated fatty acids (particularly 16:1n-7 and 18:1n-9) produced by elongation/desaturation. There was parallel upregulation of expression of genes involved in DNL and in fatty acid elongation and desaturation, suggesting coordinated control of expression. Enzyme products (desaturation ratios, elongation ratios, and total pathway flux) were also correlated with mRNA levels. We used 13C-labeled substrates to study the pathway of DNL. Glucose (5 mM or 17.5 mM in the medium) provided less than half the carbon used for DNL (42% and 47%, respectively). Glutamine (2 mM) provided 9-10%, depending upon glucose concentration. In contrast, glucose provided most (72%) of the carbon of TG-glycerol. Pathway analysis using mass isotopomer distribution analysis (MIDA) revealed that the pathway for conversion of glucose to palmitate is complex. DNL in human fat cells is tightly coupled with further modification of fatty acids to produce a range of saturated and unsaturated fatty acids consistent with normal maturation.

The extent to which the heart can convert α-linolenic acid (α-LNA, 18:3n-3) to longer chain n-3 PUFAs is not known. Conversion rates can be measured in vivo using radiolabeled α-LNA and a kinetic fatty acid model. [1-14C]α-LNA was infused intravenously for 5 min in unanesthetized rats that had been fed an n-3 PUFA-adequate [4.6% α-LNA, no docosahexaenoic acid (DHA, 22:6n-3)] or n-3 PUFA-deficient diet (0.2% α-LNA, nor DHA) for 15 weeks after weaning. Arterial plasma was sampled, as was the heart after high-energy microwaving. Rates of conversion of α-LNA to longer chain n-3 PUFAs were low, and DHA was not synthesized at all in the heart. Most α-LNA within the heart had been β-oxidized. In deprived compared with adequate rats, DHA concentrations in plasma and heart were both reduced by >90%, whereas heart and plasma levels of docosapentaenoic acid (DPAn-6, 22:5n-6) were elevated. Dietary deprivation did not affect cardiac mRNA levels of elongase-5 or desaturases Δ6 and Δ5, but elongase-2 mRNA could not be detected. In summary, the rat heart does not synthesize DHA from α-LNA, owing to the absence of elongase-2, but must obtain its DHA entirely from plasma. Dietary n-3 PUFA deprivation markedly reduces heart DHA and increases heart DPAn-6, which may make the heart vulnerable to different insults.

Rates of conversion of α-linolenic acid (α-LNA, 18:3n-3) to docosahexaenoic acid (DHA, 22:6n-3) by the mammalian brain and the brain's ability to upregulate these rates during dietary deprivation of n-3 polyunsaturated fatty acids (PUFAs) are unknown. To answer these questions, we measured conversion coefficients and rates in post-weaning rats fed an n-3 PUFA deficient (0.2% α-LNA of total fatty acids, no DHA) or adequate (4.6% α-LNA, no DHA) diet for 15 weeks. Unanesthetized rats in each group were infused intravenously with [1-14C]α-LNA, and their arterial plasma and microwaved brains collected at 5 minutes were analyzed. The deficient compared with adequate diet reduced brain DHA by 37% and increased brain arachidonic (20:4n-6) and docosapentaenoic (22:5n-6) acids. Only 1% of plasma [1-14C]α-LNA entering brain was converted to DHA with the adequate diet, and conversion coefficients of α-LNA to DHA were unchanged by the deficient diet. In summary, the brain's ability to synthesize DHA from α-LNA is very low and is not altered by n-3 PUFA deprivation. Because the liver's reported ability is much higher, and can be upregulated by the deficient diet, DHA converted by the liver from circulating αLNA is the source of the brain's DHA when DHA is not in the diet.