This paper problematizes notions of good/bad mothering by putting to work Deleuze and Guattari’s haecceity. Focusing on babywearing, it presents an autoethnography of my experiences of becoming-mother during the Covid-19 pandemic. Using diffractive analysis, I analyze the entanglement of my experiences of babywearing, research diaries, images/selfies, the regulations introduced during the pandemic, and the “global cultural script” of being a good mother. It works toward a position of (k)not knowing, being open to the unknown. Under the lens of haecceity, becoming-mother is “thisness”—a middle, knotting, and unknotting, ever emergent. This ambivalence is demonstrative of the binaries of good/bad mother and conservative versions of femininity and motherhood that permeate society . Everyday family life is increasingly scrutinized in public domains leading to moralizing, where families are at once positioned as the problem and solution  is merely a “diagram of an assemblage” (p. 292)—a becoming rather than a form taking. To take this perspective resists fixing identity and the formation of a subject—a haecceity is indeed more than the subject. Becoming-mother has been examined previously  but by p to work  to revea to work , p. 427.might be an escape from the social norms of good mothering, but it is also an individuation—becoming-mother is a haecceity. It is this. Of itself.To do this, we need to turn attention to the DeleuzoGuattarian ideas of the molar and the molecular. The molar  is not replaced by the molecular  but a potential re/de-territorialization. A Thousand Plateaus to extend my thinking on becoming, I was “jarred” by the figuration of haecceity and what potential it offered.In the 12 months since the start of the UK National lockdown in March 2020, Manchester, England, had been in some version of enhanced lockdown for over 300 days due to global COVID-19 pandemic. Amid this however, life quite literally went on, and I gave birth to a boy in the May 2020. What emerged, became something unexpected. I was on maternity leave and not consciously “researching” or “gathering” data apart from jotting a few notes down into the tiny screen of my phone at night concerning my thoughts about walking in my local area with my son. This was somewhat of an accidental autoethnography, yet it possesses a “radical specificity” . I did nDeleuze and Guattari’s (2004)Therefore, what surfaces is a diffractive analysis that seeks to account for the entanglements of engaging in and with the world. Like Haecceity, a diffractive analysis helps us to “think otherwise” I had made notes, mainly during the night into my phone while sitting in bed next to a sleeping baby. These autoethnographic diaries were not structured, but were memories and feelings jotted down in a moment of peace. Indeed, at the time they were not destined for an academic paper but as vibrancy of COVID-19 embodiment  is an entanglement between the caregiver and the baby where autonomous bodies are literally intertwined and “lived alongside and in response to” each other .He is a leaner and a leg straightener. I stumble along the uneven path holding him under his bottom to stop him falling the ground. When I tied off this carry I messed up—maybe today was not the day to experiment with a new carry. He pushes his legs downwards and throws his head back. “Come on kiddo, just stay still until I can get you sorted.” We arrive at the chemist, sweating . Masked up and trying to readjust the wrap whilst staying distanced from others waiting in line.This . . .this . . .this . . . was-not-the-day.I just want to get my flu jab and get home. She asks me to stay in the area for 10 mins in case of side effects. I am hot, my glasses have steamed up and he is not impressed. He wants his arms freeing. He starts to twist against my body. We must leave now.The bodies of the child and the mother are pressed together but neither body is static, each move and writhes—resisting each other and the fabric:bodies do?” We are not seeking to understand what the bodies mean in this haecceity—the mother body, the infant boy body—but what the entire assemblage might produce in that moment.Utilizing babywearing in attachment parenting is not straightforward as the above demonstrates, but the relations between bodies is revealing. The child has its own relations with the material and the body of the mother. They are not passive passengers, along for the ride. As Lupton (2013) explores, the infant has the capacity to disorder—his body twists and resists the wrap and my pleas to stay still. He has no desire to be held close in this moment. The idealized vision of the perfect model of attachment parent is not evident in this narrative above—the mother here is sweaty, she has lost control of the child, she is impatient. Yet it is in this “perpetual disordering” , p. 427 It should be read without a pause. , p. 290The-mother-carries-the-baby-in-the-rainA-baby-counts-as-a-person-in-the-rule-of-sixChildren-under-school-age-do-not-count-in-two-person-limitThis assemblage takes in the media discourses during the pandemic and the rules and regulations by which we were all asked to live by. These narratives were inscribed on bodies and became part of the assemblage and thus my becoming-mother during this time:What a life! What a lockdown! (a very singular individuation) . . . to paraphrase The assemblage of mothering encountering the assemblages of a pandemic, playing out in media discourses, was my early mothering experience. Spending large parts of my evening sat in bed next to a sleeping child, scouring the regulations just announced. Trying to grasp what was and was not allowed:Societal pressures to be a good mother pervades the mundane but also seeps into the unprecedented times. Wearing my child around the house out of necessity to get jobs done (to enact McRobbie’s notion of corporate family life) is also an embodiment of the stay-at-home messaging that contained my mothering. You are wrapped up secured in a beautiful woven wrap that was maybe a bit of a splurge but too gorgeous to resist. We already have carriers but this 4.6m of green cotton woven fabric will allow us to walk, body to body, for much longer. The chance to wander freely, wave at people from a distance, get my weary bones moving—brush off that cooped up feeling that creeps in . I unravel you. Carefully supporting you and lowering you into the cot—trying not to wake you. The walk has rocked you to sleep.Weknowwewilldoitallagaintomorrow.Andforthedaystocome.This . . . This . . . This . . .Not only does a haecceity reconfigure our notions of time, there is an intersection of latitudes and longitudes, a “middle”—not a middle in the sense of a balancing point or compromise, but a middle in terms of in process. To attune to the latitude of the haecceity, we see the power to affect or be affected. These “jarred” me as key affective moments:and the other away”  was imitation—it was copying. But, as haecceity it was also its own thing—it was my body and his body and the endless knotting and unknotting of the fabric. Positioning and repositioning of both our bodies. The haecceities of trying to back carry are non-representational, they are not about imitating the perfect mother but a refrain of an emergent becoming-mother.do family . Being seen, witnessed, validated my mothering—my good mothering. However, as explored above, display in both online and offline spaces is complex for the mother for whom societal pressures demand certain performances. My images of babywearing demonstrate the tensions outlined by My failure to back carry is internalized in the moment as a failure to mother. However, this image, this display on social media, does not account for the refrain of babywearing. The repetition with difference, the constant, endless mothering in motion. My mothering is always a line of flight. It is the movement of the molecular away from the molar. It is captured in the haecceity.I have spoken of imitating what babywearing should look like, thus what I thought mothering should look like . MacLureWhat constitutes a good mother is problematized in this diffractive analysis. As The individuation of the mother as a subject is prevalent in narratives of being a competitive participant in the workforce and a neoliberal emphasis on the individual but when examined as “thisness” the mother-child-wrap assemblage in this paper reveals an entanglement where these competing forces are neither good nor bad. The push and pull of becoming our own versions of something is more than the subject. Therefore, the call of


Stump appendicitis is a rare complication of appendectomy because of recurrent inflammation of the residual appendix. The diagnosis is often delayed because of low index of suspicious, which may result in serious complications. Twenty-three-year-old male patient presented with right lower quadrant abdominal pain after 7 month of appendectomy done at a hospital. On physical examination, he has right lower quadrant tenderness and rebound tenderness. Abdominal ultrasound was done with finding of blind-ended tubular noncompressible 2 cm long part of appendix with wall-to-wall diameter of 10 mm. There is also focal defect with surrounding fluid collection. With this finding, perforated stump appendicitis was diagnosed. He was operated with similar intra operative finding. The patient discharged improved after 5 days of hospital. This is first reported case in Ethiopia as far as our search is concerned. Despite past medical history of appendectomy, the diagnosis was made by means of ultrasound scan. Stump appendicitis is a rare but important complication of appendectomy, often misdiagnosed. Prompt recognition is important to avoid serious complications. This pathologic entity should always be kept in mind in case of right lower quadrant pain in patient with previous history of appendectomy. Acute appendicitis is the commonest surgical operation, and appendectomy forms a major bulk of the emergency surgery performed in the emergency room. Although stump appendicitis is a complication of appendectomy, it is rare, whereas wound infection, pelvic abscess and adhesive bowel obstruction are more commonly seen among others.Most clinicians do not consider stump appendicitis as a differential diagnosis when evaluating a patient with right lower abdomen pain who has undergone appendectomy in the past. It is a challenging condition that is usually diagnosed and confirmed by means of imaging, especially by US and CT. A few number of stump appendicitis are reported in the medical literature. Here, a 23-year male with stump appendicitis is described, with a previous history of appendectomy.A 23-year-old male patient presented with abdominal pain of 4-day duration. The pain increased in intensity 24 hour prior to his arrival to our hospital. The pain gets worse with movement and he has associated some episodes of vomiting. He complains low-grade fever. He has history of open appendectomy 7 month back at the same hospital.On physical examination, he has rebound tenderness in right lower quadrant in the proximity of a well-healed McBurney’s’s incision scar. Psoas sign was also positive.His axillary temperature was 38.4°C. Base line investigations showed white blood cells 13.070/mmc with slight neutrophilia at 11.490/mmc. Urine analysis and stool examination were normal.Abdominal ultrasound was done and there was dilated tubular and blind-ended appendix, which has connection cecum. It is not compressible with outer-to-outer wall diameter of 10 mm as shown in On the same day, exploratory laparotomy with a lower midline incision was performed under general anesthesia. The operative findings were inflamed stump of appendix (~2 cm) with perforation at its tip with surrounding abscess collection. Rest of the bowel was normal. Completion appendectomy was performed and the postoperative period was uneventful, and on postoperative Day 5, the patient was discharged  and B.Acute appendicitis is the commonest abdominal surgical emergency encountered in clinical practice . It is aThe first appendectomy was performed in 1735 by Claudius Amyand, and in 1886, Reginald Fitz described the clinicopathological features, whereas Rose described stump appendicitis for the first time in 1945 . There iStump appendicitis is defined as a rare complication following appendectomy caused by inflammation of the residual portion of the appendix left behind. The clinical presentation of stump appendicitis is similar to that of acute appendicitis . Stump aGenerally, during surgery, adequate visualization of the appendix base and the ileocecal region and a stump of <5 mm reduces the risk of stump appendicitis . AlthougStump appendicitis is associated with late diagnosis and therefore has a higher rate of perforation with increased morbidity . The facA correct preoperative diagnosis of stump appendicitis can be made by ultrasonography and by computed tomography. Ultrasonography can reveal a thickened appendix stump, fluid in the right iliac fossa and edema of caecum. Abdominal sonography has become the method of choice for the diagnosis of acute appendicitis since Puylaert’s technique was adopted . In our While CT scan is said to be superior to USG , but in In developing countries like ours where sophisticated examination like CT, MRI, barium enema or colonoscopy are not routinely available, we think in agreement with other authors, that in most cases the diagnosis of stump appendicitis may be made by ultrasonography alone. Since ultrasound is operated dependent, high index of suspicion and a certain familiarity with sonographic finding are necessary and sufficient prerequisites for an early diagnosis. This can reduce clinical dilemma to diagnose stump appendicitis and more importantly reduce complication related with delay to diagnose. In our case, the patient has stump appendicitis perforation, which is the commonest complication. But ultrasound diagnosis was made preoperatively. So this complication may be explained by late patient presentation, 4 days after onset of pain .The treatment of choice is completion appendectomy, either open or laparoscopically . SometimIn conclusion, stump appendicitis is a rare but serious complication of appendectomy, often confused with other conditions. The prevalence and the incidence of stump appendicitis have been increasing in recent years, probably because of the increased use of laparoscopic approach to appendectomy. Prompt recognition is important to lead to early treatment, thus avoiding serious complications. It must be clear that the history of prior appendectomy does not rule out the possibility of a stump appendicitis. High degree of suspicion can help to make a correct diagnosis and a safe treatment. Therefore, radiologist should be familiarized and aware of this rare but important finding for timely diagnosis. Clinicians should also always keep in mind the possibility of this complication as the cause of right lower quadrant pain.None declared.None.


The multicomponent approach allows to incorporate several functionalities into a single covalent organic framework (COF) and consequently allows the construction of bifunctional materials for cooperative catalysis. The well‐defined structure of such multicomponent COFs is furthermore ideally suited for structure‐activity relationship studies. We report a series of multicomponent COFs that contain acridine‐ and 2,2’‐bipyridine linkers connected through 1,3,5‐benzenetrialdehyde derivatives. The acridine motif is responsible for broad light absorption, while the bipyridine unit enables complexation of nickel catalysts. These features enable the usage of the framework materials as catalysts for light‐mediated carbon−heteroatom cross‐couplings. Variation of the node units shows that the catalytic activity correlates to the keto‐enamine tautomer isomerism. This allows switching between high charge‐carrier mobility and persistent, localized charge‐separated species depending on the nodes, a tool to tailor the materials for specific reactions. Moreover, nickel‐loaded COFs are recyclable and catalyze cross‐couplings even using red light irradiation. Various multicomponent COFs bearing both a moiety for photosensitization and complexation of nickel catalysts were synthesized using reticulation with different 1,3,5‐triformylbenzene nodes. This enabled the switching between persistent, charge‐separated species or efficient charge‐carrier mobility for different metallaphotocatalytic cross‐coupling reactions based on the node unit. The frameworks showed recyclability and the possibility to drive the reactions using red light irradiation. Combining two or more catalysts that work in concert to enable the formation of a chemical bond  has recently become a powerful addition to the synthetic chemist's toolbox.The interaction between the catalysts in solution requires persistent excited state lifetimes of the photocatalyst as it must be longer than the time it takes to diffuse to the nickel complex to induce catalysis. Thus, these transformations are limited to photocatalysts that populate triplet excited states with high quantum yields, such as Ir or Ru polypyridyl complexes,Close spatial proximity between the two catalysts is arguably beneficial for electron (or energy) transfer events between the two catalytic species, but this parameter is difficult to tune using homogeneous catalysts. Immobilizing the photo‐ and the nickel catalyst on a support enables controlling the distance between the individual catalysts at the nanoscale. For example, iridium polypyridyl‐ and nickel bipyridine complexes were integrated in metal‐organic frameworks (MOFs),9, 10 Another appealing strategy is to integrate a nickel catalyst directly into a photocatalytically active polymeric material. Seminal approaches include the incorporation of nickel atoms into carbon nitride materials,20, 21β‐ketoenamine to imine ratio on the node that connects the linkers is a key parameter influencing charge‐carrier separation. Others have reported the integration of nickel complexes into a photocatalytically active COF structure to realize visible‐light mediated cross‐couplings[Covalent organic frameworks (COFs) are well‐defined, crystalline, highly porous polymers with tunable structures that are prepared by covalently attaching multiconnected nodes with linear linkers, which can introduce functional groups into the backbone.27, 28β‐ketoenamine to imine ratio significantly varies the efficacy of such COFs as catalysts for C‐S and C‐N cross‐couplings. Our results show that the imine‐form leads to high charge‐carrier mobility that is ideal for activating nickel sites that are ligated at the COF backbone. In contrast, β‐ketoenamine tautomerized COFs have localized, persistent charge‐separated species that are key for diffusion limited interaction with homogeneous nickel complexes.Inspired by these studies, we hypothesized that a multicomponent COF prepared from an acridine linker, a linking unit that provides coordination sites for nickel, and benzene‐1,3,5‐tricarbaldehyde derivatives as 3‐connected (3‐c) nodes would enable detailed structure‐activity relationship studies that shine light on parameters that influence the activity of such bifunctional multicomponent COF metallaphotocatalysts. Here, we show that the β‐ketoenamine to imine ratio on charge‐carrier mobility. 1,3,5‐triformylphloroglucinol (Tp) was used to synthesize the irreversible keto tautomeric COFs, whereas 1,3,5‐triformylbenzene (Tf) carries no tautomerizable group and thus yields a fully imine linked COF  were synthesized by an acid catalyzed Schiff base reaction .Our investigations started with the synthesis of a set of eight multicomponent COFs using 2,6‐acridinediamine (Acr) as chromophoric linker and 2,2’‐bipyridine‐5,5’‐diamine (Bpy) as metal binding site Figure . Since bF Figure . 2,4‐dihα radiation  facet of a primitive hexagonal lattice. Weaker reflections in the 2θ=5–10° range and a broad peak at 2θ=26.5° degrees confirmed the formation of crystalline, π‐π stacked two‐dimensional structures for all COFs. According to the symmetry of the linkers, the structural models for the multicomponent COFs were constructed by generating the expected 2D layers with hcb topology. The models were geometrically optimized, and their corresponding theoretical PXRD patterns were compared to the experimentally measured patterns. Theoretical diffraction patterns of models with eclipsed stacking sequences (AA) are in good agreement with the measured diffractograms .The crystallinity of the synthesized COFs was determined by powder X‐ray diffraction (PXRD) analyses using Cu K Figures  and S5. 2‐L‐Bpy1 COFs, Acr2‐HTA‐Bpy1 showed the highest specific surface area (1093 m2/g). The fully imine‐based COF Acr2‐Tf‐Bpy1 showed the lowest surface area of 210 m2/g. A different trend was found for Acr1‐L‐Bpy2 COFs, where the highest surface area was obtained using DHTA (926 m2/g) and the lowest using HTA (175 m2/g). The pore size of all Acr2‐L‐Bpy1 COFs are close to theoretical values .Nitrogen sorption measurements at 77 K confirmed the porosity of all COFs Figures  and S6. Fourier transform infrared (FTIR) spectroscopy confirmed the formation of the framework materials. Characteristic signals of the precursors disappeared, while peaks that can be assigned to C=O and C=C or C=N vibrations, respectively, are present after the COF synthesis . Thermal stability of the multicomponent COFs was investigated using thermogravimetric analysis (TGA). After an initial weight loss due to adsorbed moisture and solvent molecules, all materials were thermally stable up to 350 °C .13C cross‐polarization magic angle spinning nuclear magnetic resonance (CP‐MAS NMR) analyses . For Acrx‐Tp‐Bpyy COFs, a distinct carbonyl carbon (C=O) peak around 180–185 ppm as well the C=C signal at 105 ppm confirm the dominant presence of the keto form.x‐Tf‐Bpyy, indicative of increasing amounts of imine tautomers among the series. Signals between 115–150 ppm confirm the presence heteroaromatic linkers in all COF backbones. Diagnostic signals at 150 and 133 ppm were assigned to the bipyridine motif and confirm an increasing bipyridine:acridine ratio when higher amounts of 2,2’‐bipyridine‐5,5’‐diamine were used for the COF synthesis .[The structural integrity of frameworks was studied by re S25b).46, 47x‐Tf‐Bpyy . Aromatic nitrogen atoms of the acridine and bipyridine atoms show a signal with the binding energy of 399 eV in the N 1s spectrum. The different amounts of bipyridine units within the COF backbones can be determined qualitatively, with a more pronounced signal for Acr1‐Tp‐Bpy2 compared to Acr2‐Tp‐Bpy1. For the other COFs this peak is overlying with the signals of the imine and enol bonded nitrogen atoms. To quantitatively determine the amount of Acr and Bpy units in the backbone of the multicomponent materials, Acrx‐Tp‐Bpyy COFs were digested in a solution of 0.1 mL of 10 M NaOH in D2O and 0.5 mL DMSO‐d6 at 120 °C and subsequently analyzed with 1H NMR. Integration of the peaks at 7.89 and 7.69 ppm that can be assigned to Bpy and Acr, respectively, show that the amount of substrates used in the synthesis is in agreement with the incorporated ratio of the two linkers, demonstrating no preferential reaction of the linkers .X‐ray photoelectron spectroscopy (XPS) also depicted the gradual reduction of keto‐enamine tautomerization in the series of COFs. Deconvolution revealed signals in the N 1s spectrum at 400 eV and 398.8 eV that can be assigned to the secondary amine group of the keto‐enamine linkage and imine and pyrdinic groups, respectively. The ratio between these signals gradually decreases with decreased number of tautomerizable groups and vanishes for fully imine‐based COFs Acr2‐L‐Bpy1 COFs (Section S4.10), confirming our experimental findings.Using diffuse reflectance ultraviolet‐visible (UV‐vis) spectroscopy we confirmed that multicomponent COFs broadly absorb across the visible‐light spectrum Figures  and S15a2‐Tf‐Bpy1 was tested ex situ by refluxing a suspension of the COF and NiCl2⋅glyme in acetonitrile  and shows rather undefined morphology of the particles  was used to quantify the immobilization of the transition metal (Table S9) and showed a nickel loading of 3.59 mg g−1 corresponding to an occupation of 5.1 % of bipyridine functionalities.Before testing the materials in cross‐coupling reaction as suitable catalysts, nickel complexation at Acre Figure . After cs Figure . ElementF Figure . The Ni x‐L‐Bpyy COFs in hand, we sought to study if these bifunctional materials are suitable as heterogeneous metallaphotocatalysts for carbon‐heteroatom cross‐couplings in presence of a nickel(II) salt (in situ complexation). Indeed, Acr2‐Tf‐Bpy1 showed high catalytic activity in the C−S coupling of 4‐iodobenzotrifluoride with methyl 3‐mercaptopropanoate. Almost quantitative formation of the desired product (1) was achieved within three hours using 440 nm LEDs . No reaction occurred in the absence of a base or light . Nickel complexation can also be carried out prior to catalysis (Entry 6).With the fully characterized Acrs Figure , Entry 12‐Tf‐Bpy1 shows high catalytic activity using green light (Entry 7) and even results in quantitative product formation after 48 h using red LEDs (Entry 8).High energy of blue light potentially causes deactivation of nickel catalysts and can lead to undesired side reactions.2‐L‐Bpy1 COFs as catalysts, for the same cross‐coupling reaction a clear trend regarding the nodes was identified . However, the related C‐N coupling between pyrrolidine and 4‐bromobenzotrifluoride showed a reversed trend  and 4‐iodobenzotrifluoride in acetonitrile is irradiated compared to the Acr2‐Tp‐Bpy1‐Ni .This discrepancy can be rationalized by the different involved mechanisms. C−S couplings require coordination of Ni to a bipyridine ligand. In C−N cross‐couplings, the secondary amine is added in large excess, because it simultaneously serves as substrate, base and, more importantly, ligand for the first‐row transition metal.2‐Tf‐Bpy1 with two other catalytic systems in the cross‐coupling of 4‐iodobenzotrifluoride with methyl 3‐mercaptopropanoate  and the nickel center in combination with the high charge‐carrier mobility is superior to related, diffusion limited transformations. We compared the catalytic activity of in situ nickel loaded Acrπ‐π stacking interactions by treating the material with light.[2‐Tf‐Bpy1‐Ni or nickel(II) salt. The bifunctional, nickel charged COF could be recycled five times without significant loss in catalytic activity, suggesting that the nickel atoms strongly coordinate to the bipyridine linkers in the COF. After the last cycle, a nickel loading of 10.3 mg/g showed that most of the nickel atoms present after the first cycle are still immobilized. FTIR spectroscopy confirmed the intact chemical structure of the COF after the reaction , which proves that the short‐range order of the material is preserved, although the long‐range periodicity is lost under photocatalytic conditions. Additionally, the morphology of the material was analyzed by TEM and did not alter during the recycling study  light in the thioetherification Figure . The firth light.37, 51 Figures  and S33. Figures . This coβ‐ketoenamine to imine ratio in the frameworks on catalytic activity. Our results show that the imine‐form is key for high charge‐carrier mobility that transfers conduction band electrons located at the acridine photocatalyst to an active nickel center that is attached at the bipyridine moieties. In contrast, persistent charge‐separated species located at the acridine moiety are formed upon excitation of COFs that have β‐ketoenamine connections. This was shown to be beneficial in the diffusion limited activation of homogeneous nickel complexes. A multicomponent COF that hosts nickel atoms was further shown to be a recyclable heterogeneous C−S cross‐coupling catalyst that can be activated with long wavelengths.In summary a series of multicomponent COFs containing a bipyridine and acridine linker were prepared using different three‐connected nodes and their application as catalysts for light‐mediated nickel catalyzed carbon−heteroatom cross‐couplings was evaluated. Four different 1,3,5‐triformylbenzene derivatives were selected as nodes to study the influence of x‐L‐Bpyy COFs Synthesis of Acr: A typical COF synthesis is exemplified for Acr2‐Tf‐Bpy1. A Pyrex tube (o.d. × i.d.=15×10 mm2 and length 15 cm) is charged with 1,3,5‐triformylbenzene (Tf) , 2,6‐diaminoacridine (Acr) , 2,2′‐bipyridine‐5,5′‐diamine (Bpy) , 1.5 mL of n‐BuOH, 1.5 mL of anhydrous o‐DCB and 0.5 mL of 6 M aqueous acetic acid. This mixture was sonicated for 15 minutes in order to get a homogenous dispersion. The tube was then flash frozen at 77 K (liquid N2 bath) and degassed by three freeze‐pump‐thaw cycles. The tube was sealed off and then heated at 120 °C for 3 days. A dark red colored precipitate was collected by filtration and washed with acetone, methanol and cyclohexane. The powder collected was dried at 120 °C to give a dark red colored powder.General experimental procedure for photocatalytic experiments: An oven dried vial (19×100 mm) equipped with a stir bar was charged with NiCl2⋅glyme (4–12 μmol), Acrx‐L‐Bpyy COF, 4‐halobenzotrifluoride and nucleophile. The solvent (anhydrous) was added and the vessel was sealed with a septum and Parafilm. The mixture was stirred for 1 minute at high speed, followed by sonication for 5 minutes and degassing by bubbling argon for 10 minutes. The reaction mixture was stirred at 800 rpm and irradiated with 440 nm, 535 nm or 666 nm LED lamps. After the respective reaction time, 1,3,5‐trimethoxybenzene (1 eq.) was added as internal standard to the reaction vessel, the mixture was shaken and an aliquot (200 μL) was removed, filtered, diluted with DMSO‐d6 and analyzed by 1H NMR.The authors declare no conflict of interest.1As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.Supporting InformationClick here for additional data file.


In this paper, we report an in situ study regarding the microstructural evolution of a nickel-based alloy with high proportional twin boundaries by using electron backscatter diffraction techniques combined with the uniaxial tensile test. The study mainly focuses on the evolution of substructure, geometrically necessary dislocation, multiple types of grain boundaries , and grain orientation. The results show that the Cr20Ni80 alloy can be obtained with up to 73% twin boundaries by annealing at 1100 °C for 30 min. During this deformation, dislocations preferentially accumulate near the twin boundary, and the strain also localizes at the twin boundary. With the increasing strain, dislocation interaction with grain boundaries leads to a decreasing trend of twin boundaries. However, when the strain is 0.024, the twin boundary is found to increase slightly. Meanwhile, the grain orientation gradually rotates to a stable direction and forms a Copper, S texture, and α-fiber <110>. Above all, during this deformation process, the alloy is deformed mainly by two deformation mechanisms: mechanical twinning and dislocation slip. Nickel-based alloy are widely used in demanding environments, such as aerospace, energy, and chemical industries, due to their excellent corrosion resistance and mechanical properties ,2,3,4. TThe Cr20Ni80 alloy is a stable austenitic alloy with a Cr replacement of Ni due to no phase change at different temperatures. It is a nickel-based alloy with excellent corrosion resistance and outstanding mechanical properties, and it is widely used in machinery, metallurgy, and industrial furnaces. As far as we know, there have been many studies reported on the cold working of the Cr20Ni80 alloy; for example, Zhou et al. ,11 reporGBs are interfaces separating grains of different crystallographic orientations that have an important effect on the plastic deformation of polycrystalline materials . In addiElectron backscatter diffraction (EBSD) is important in analyzing the mechanical properties and characterizing the microstructure of crystalline materials ,18,19. FIn this study, the evolution of GBs, substructure, and orientation of the Cr20Ni80 alloy during deformation is objectively and comprehensively analyzed and studied by combining high-temperature annealing (GBE) and in situ EBSD techniques so that the microstructural evolution and deformation behavior of the alloy with a high proportion of TBs can be better understood. Additionally, this study provides an experimental basis for simulation studies and contributes to the development of cold processing.The material investigated in this paper is a commercial Cr20Ni80 alloy sheet with a thickness of 1 mm, which is usually prepared by the cold rolling technique. The alloy’s chemical composition (in wt.%) is 20.15 Cr, 0.27 Mn, 0.59 Fe, 0.29 Al, 1.17 Si, 0.032 C, 0.0032 S, 0.01 P, and Ni balance. The alloy is kept at 1100 °C for 30 min and then air-cooled , subsequently machined by an electric discharge machine into a 10 mm (L) × 2 mm (W) in situ tensile sample, as shown in In situ tensile testing is performed at room temperature by an automated tensile system, which consisted of a tensile table mounted to an Ultra-55 Zeiss field emission scanning electron microscope (SEM). The EBSD tensioning table with a maximum load of 2000 N is shown in The true stress–strain curve of the specimen in the in situ EBSD test is shown in The band contrast (BC) value is qualitatively correlated with the defect density in the signal excitation region, so the BC map can be used to qualitatively illustrate the magnitude of the defect density. The BC map is a two-dimensional grayscale map based on the reconstruction of the Kikuchi diffraction pattern by EBSD, which is similar to the SEM and secondary electron image. The BC map of the original microstructure of the specimen is shown in The EBSD Inverse Pole Figure (IPF) maps are plotted in the ND direction of the specimen. GBs are the interfaces separating grains with different grain orientations, which have important effects on the plastic deformation mechanism and mechanical properties of metallic materials . Based oUnder large stresses, TBs are destroyed, the grains are refined, and the proportion of TBs is dramatically reduced, while LAGBs are significantly increased. TBs can absorb movable dislocations , and somKernel average misorientation (KAM) is commonly used to characterize the specimen’s local strain distribution and dislocation density . The KAMρGND is the GND density, b is Burger’s vector, μ is the unit length of the point, and θ is the average local misorientation angle.As is well known, the dislocation density is closely linked to the strain, and the dislocation density is positively correlated with the average local misorientation. To quantitatively study the evolution of dislocation density during deformation, the average local misorientation measures are used to investigate the geometrically necessary dislocation (GND) variation during deformation, and the EBSD test data is used for the calculation. The GND density can be expressed as follows : (2)ρGNDThe relationship between strain and GND density is shown in A Recrystallized Fraction (DefRex) Map is usually used to characterize each grain’s microstructure changes during the deformation process. In this paper, according to the misorientation angles of each adjacent tiny region within the grains, the grains are divided into recrystallized (<1°), substructured (1°–7.5°), and deformed (>7.5°) grains, which are marked in blue, yellow, and red, respectively, in the DefRex Map.To further analyze the evolution of the microstructure during deformation, the distribution of different grains under different strains is statistically analyzed, as shown in σ0.2 is yield strength, τc is critical shear stress , φ and λ are the angles formed by the stretching direction and the normal direction of the slip plane {111} and the slip direction <110>, respectively, and (cos(φ)cos(λ)) is the Schmid Factor.It is well known that the level of shear stress exerted on the slip surface and direction determines the plastic deformation of the crystalline material . Nickel-The Schmid Factor (SF) represents the probability that the crystalline material will initiate a slip system in a certain direction (how difficult it is to deform). The higher the SF value, the higher the probability of the slip system activation. As shown in The grain with a higher SF value means the grain is soft orientation, comparing the value of SF in different states. It can be seen that the SF value does not change significantly at low and medium strains, while at large strains, the yellow regions suddenly increase and some green regions appear, indicating that the SF value gradually decreases with increasing strain. We performed statistical calculations on SF values to further accurately analyze the relationship between SF values and different strains. In general, there are 3 to 5 slip systems operating simultaneously in each region within the grain during the deformation process . With inφ2 = 0°, 45° and 65°). For clarity, the ideal basic texture components of the nickel-based alloy are shown in In crystallography, the orientation of most grains is usually concentrated in a direction—this phenomenon is called texture. The texture is closely related to the stress state of the sample . In polyThe Copper and S orientations have low SF values, whereas the Brass and Goss orientations have high SF values. Consequently, it is difficult to deform the grains in the Copper and S directions during cold deformation, which tends to cause uneven stresses that promote shear band formation and increase the local strain in the specimen . GeneralDuring the deformation of the Cr20Ni80 alloy, the proportion of low-angle grain boundaries gradually increases, the twin boundaries tend to reduce, and the substructure gradually increases. Meanwhile, mechanical twinning is found to occur at low strain. The alloy is deformed mainly by two deformation mechanisms: dislocation slip and mechanical twinning.Dislocations preferentially accumulate near the twin boundary, and the strain localizes at the twin boundary with increasing strain. Meanwhile, at low strains, the geometrically necessary dislocation increases slightly with increasing strain. However, the geometrically necessary dislocation proliferates explosively under large strains, the different slip systems operate in combination, and adjacent grains interact with each other with uneven stresses, which destroys many grains. This above phenomenon can be linked to two strengthening mechanisms (dislocation strengthening and grain boundary strengthening), causing a strong work-hardening effect.The Copper and S orientations have low Schmid Factor values, whereas the Brass and Goss orientations have high SF values. In addition, dislocation proliferates, and interaction with dislocations and grain boundaries leads to lattice rotation, resulting in a gradual decrease in the intensity of the Brass texture and an increase in the intensity of the Copper and S texture during deformation. Meanwhile, with strain increasing, the slip system {111} <110> is activated so that dislocations start to slip along the {111} slip plane, and the grain orientation gradually rotates to a stable direction, forming the α-fiber <110>. Therefore, the grains gradually rotate toward lower Schmid Factor values during plastic deformation, eventually forming the cold deformation texture such as α-fiber (RD//<110>), R {124} <211>, S {123} <634>, and Copper {112} <111>.In this paper, the microstructural evolution of a nickel-based alloy with a high proportion of twin boundaries was tracked by in situ EBSD and a uniaxial tensile test. Additionally, the sample was treated by high-temperature annealing (grain boundary engineering) to obtain up to 73% twin boundaries. Grain rotation, grain boundary evolution, and substructure transformation were studied and analyzed in detail. The microstructural evolution of the alloy was carefully studied during deformation, and the main conclusions are as follows:


A better knowledge of HEV virology is therefore needed. By providing descriptions of the three-dimensional structures of viral proteins at atomic level, structural biology can be a powerful tool to understand viral replication and help develop specific antivirals. In this comment, we describe how both experimental and advanced computational structural biology help to decipher HEV virology and make a case for heeding its lessons.Hepatitis E virus (HEV) infects approximately 20 million individuals each year all around the world, both in developing and industrialized countries. It leads to 40,000–70,000 deaths annually, especially in immunocompromised patients and pregnant women. Despite its recognized major public health issue status and zoonotic potential, no specific treatment is available. Indeed, HEV life cycle characterization is hampered by the lack of efficient infectious cell culture systems or et al. used sequence-based computational tools to perform sequence alignments with some closely related (+)RNA viruses belonging to the Alphavirus-like superfamily and define domain boundaries of pORF1 RNA viruses. Since then, the HEV community has taken to referring to HEV pORF1 residues 434–592 as “the PCP domain” or “the HEV protease.”HEV pORF1 is the replication polyprotein encoded by open reading frame 1. It contains domains that ensure the synthesis of new viral RNA genomes in infected cells. As for other single-stranded positive-sense RNA viruses [(+)RNA viruses], it encodes the viral replication complex  and presumably includes domain(s) that allow targeting to and remodeling of a specific host endomembrane to shelter the replication complex. pORF1 organization was delineated promptly after virus identification in the early 1980's Khuroo,  and genoHowever, structural biology has recently shown that this initial assignment was erroneous, both with an experimental X-ray crystal structure and with groundbreaking computational tools, including those based on artificial intelligence (AI). As summarized below, it is now clear that HEV pORF1 does not contain any protease domain, either in residues 434–592 or anywhere else.i.e. a region of a protein that is self-stabilizing and folds, functions and evolves independently from the rest. Thus, it is actually established since 2019 that residues 434–592 cannot be a protease domain.First, in 2019 Proudfoot et al. solved the crystal structure of the 510–690 fragment of a gt1 HEV pORF1  tool  that is likely to bind divalent cations, most probably zinc (Dearborn et al., We are at a watershed in HEV biology in which too many researchers still refer to the HEV PCP, despite the hard data we just outlined. This situation is very well exemplified by the work of LeDesma et al. recently published in eLife (LeDesma et al., In the light on these new data, we think it is time to stop using the terms “HEV protease” or “PCP domain,” as the corresponding region is now established to be neither a PCP nor even a domain, and to heed the contribution of structural biology in probing the actual functions of this part of HEV pORF1.SF: Conceptualization, Funding acquisition, Writing—original draft, Writing—review and editing. TT: Visualization, Writing—review and editing. SB: Conceptualization, Funding acquisition, Writing—review and editing.


The equibiaxial planar tension test can enhance uniform deformation and reduce stress errors to as low as 2.1% (at λ = 4) with single-corner-point tension. For circular diaphragm specimens in radial tension tests, increasing the number of cuts and using larger punched holes results in more uniform deformation and less stress error, with a minimum value of 3.83% achieved for a specimen with 24 cuts and a 5 mm punched hole. In terms of tensile efficiency, increasing the number of tensile points in the equibiaxial planar tension test can improve it; under radial tension, increasing the number of cuts and decreasing the diameter of the punched hole on the specimen has a hedging effect. The findings of this study are valuable for accurately evaluating various equibiaxial tension methods and analyzing their precision, as well as providing sound guidance for the effective design of testing apparatus and test plans.For rubber-like materials, there are three popular methods of equibiaxial tension available: inflation tension, equibiaxial planar tension, and radial tension. However, no studies have addressed the accuracy and comparability of these tests. In this work, we model the tension tests for a hyperelastic electroactive polymer (EAP) membrane material using finite element method (FEM) and investigate their experimental accuracy. This study also analyzes the impact of apparatus structure parameters and specimen dimensions on experimental performances. Additionally, a tensile efficiency is proposed to assess non-uniform deformation in equibiaxial planar tension and radial tension tests. The sample points for calculating deformation in inflation tensions should be taken near the top of the inflated balloon to obtain a more accurate characteristic curve; the deformation simulation range will be constrained by the material model and its parameters within a specific limit ( Because friction between contact surfaces during uniaxial compression tests for rubber-like materials causes complicated stress states such as compression and shear, resulting in inaccurate results, equibiaxial tension tests are commonly used to replace compression tests for rubber-like materials and have recently gained popularity for assessing the mechanical properties of hyperelastic membranes. The inflation tension test for inflating circular specimens ,2, the eThe inflation tension is first employed for the equibiaxial tension test after being motivated by the phenomenon of an inflated balloon expanding into a balloon with equibiaxial deformation. Treloar  developeFollowing the pioneering work of Lanir and Fung on the rabbit skin test in 1974 , the equUnlike inflating a thin elastomer membrane using air pressure, the disc specimen can achieve an equibiaxial state of stress and strain in a plane by applying a constant load around its perimeter. Usually, a specific radial tension apparatus has been employed for circular sheet specimens with cuts and punched holes ,19, whicDespite the widespread use of various equibiaxial tension test methods, no comprehensive comparative analysis of these methods and their accuracy has been published due to their complexity. Since it requires fewer physical prototypes and experiments during the design cycle, FEM is now widely utilized to develop and optimize complex processes or products. There is no question that using the FEM to assess the equibiaxial tension test method is an achievable choice.VHB acrylic series hyperelastic EAP elastomers provided by 3 M™ exhibit remarkable characteristics of large elasticity and strain energy density, making them highly promising for applications in high-tech fields such as soft robotics ,21, flexThe impact of apparatus structure and specimen geometry parameters on experimental accuracy and other performance factors is also addressed. Additionally, the concept of tensile efficiency is introduced to analyze non-uniform deformation in equibiaxial planar tension and radial tension tests. The stress equation is utilized to explain the reason for the limited deformation simulation range of inflation tensions. This paper’s conclusion can guide the selection and application of equibiaxial tensile testing.Various hyperelastic models are available for rubber-like materials . A hybriklC is the Mooney–Rivlin material parameter and N is the model order. In practical application, the first two terms of its power series are usually taken, i.e.,I1 and I2 are the strain invariants of the Cauchy–Green deformation tensor, which are determined by the stretch ratios iλ  in three principal directions. The stretch ratio is the ratio of the geometric dimension of the stretched specimen to the original one in those directions.For incompressible materials, the SEDFs can also be considered as a function of two strain invariants ,33:(1)W=I1 is partially expanded, the typical third-order Yeoh SEDFs can be obtained [In the SEDFs formula of Mooney–Rivlin, if only invariant obtained :(5)W=C10kμ, kα are the material parameters. The above-mentioned Ogden SEDFs usually take another form [Ogden removed the restriction that the SEDFs are an even power of the stretch ratio and proposed a SEDFs in the series form :(6)W =∑kher form ,10:(7)W λ1λ2λ3 = 1, the SEDFs can be simplified.This formula is also used in the FEM software, Abaqus 6.14. It is the same as the original formula, with only a formal difference. For incompressible materials, with the relation iσ  can be derived as follows:Ph is the hydrostatic pressure determined by the dynamic boundary condition. Since the third dimension (thickness) is much smaller than the other two planar dimensions, it can be well approximated to a planar tensile state with σ3 = 0, and the expressions of the stress in two principal directions under the condition of equibiaxial tension can be deduced:According to the SEDFs, the principal Cauchy stress σ can be derived with the assumption of isotropy and incompressibility, where I1 and I2 asThe equibiaxial tensile stress S and stretch ratio λ, where S equals Cauchy stress  divided by λ:The stress formula for various models of equibiaxial tension can be found by substituting the above-mentioned SEDFs into Equations (9) or (10). The mechanical behavior of hyperelastic materials is typically expressed as the relationship between engineering stress The EAP investigated in this study is VHB4910, a commercial double-sided adhesive tape belonging to the acrylic polymer family and commonly used in the production of flexible actuators due to its high deformation capacity under an electric field. The material model parameters are obtained from the literature [In practice, the methods used to derive mechanical behavior from equibiaxial tension tests vary. Therefore, it is necessary to evaluate equibiaxial tensions through simulations. The model updating method, standardized tests, and the multi-response surface method (MRS) can be combined with desirability functions to automatically determine the most appropriate constants for modeling material behavior using FEM . ConsequIn an inflation tension, the elastic disc diaphragm’s perimeter is held in place during the test while hydraulic oil (or compressed air) is applied to its bottom surface, causing it to expand into a balloon form In the inflation tension, membrane deformation is typically estimated from sampled points in the deformation zone closer to the vertex of the inflated balloon. During inflation, changes in position of the balloon vertex and surrounding points are recorded and selected for relevance calculation, allowing stretch ratio to be calculated accordingly .P0 refers to the vertex, which coincides with the center of the disc diaphragm in its initial state without deformation; iθ and iθ = θi+1 − iθ; Ri represents the curvature radius at the point iP and iL is the chord length in the equation, while Assuming a balloon-like shape, two observation points situated along the longitude of the inflated surface, Ri and stretch ratios of the inflated balloon’s surface points. The balloon vertex usually serves as the starting point and then the curvature radius Ri becomes an average one.When the distance between two observation points is sufficiently short, the equations can be used to approximate and determine the curvature radius R, longitudinal stretch ratio λ, compressed air (or hydraulic oil) pressure p, and membrane thickness t, assuming that the inflated form in the inflation tension is “balloon-like” [t0 is the membrane’s initial thickness, and the manufacturer-specified value for the VHB4910 membrane is 1 mm.The equibiaxial tensile stress can be determined using the curvature radius on-like” :(18)σ=pRDb) and thickness (Hb), which also determine the transition arc radius (Hb/2). Therefore, this simulation focuses primarily on deformation uniformity and how the structural dimensions of the apparatus affect experimental accuracy, with Hb = 6 mm and Db = 54 mm utilized in the simulation.The homogeneity of deformation has a significant impact on the accuracy of inflation tension tests. As a circular diaphragm specimen, the primary factors influencing test results are the structural dimensions of the apparatus, specifically the upper flange’s inflation hole diameter  model for the EAP membrane specimen. To satisfy the axial symmetry boundary conditions, a cylindrical coordinate system is adopted, as depicted in Equibiaxial planar tension is a technique that induces equibiaxial plane deformation by delivering uniform tensile stress (or displacement) to the periphery of a square membrane specimen b. MechanTo improve the uniformity of deformation in the membrane specimen’s corner area, a single-corner-point tension approach can be applied. In the approach, the connecting plate between the two points adjacent to the corner in S can be derived by measuring and calculating the total axial tensile force F, then dividing it by the initial cross-sectional area A0 of the square membrane.Ls is the square membrane specimen’s edge length. The axial tensile force F in the simulation is calculated by summing the tensile forces at each tensile point along the edge and the values of the force component near or at the corner. The displacement of the testing marks can be used to calculate the stretch ratio in equibiaxial planar tension.The nominal stress ηλ is defined as the ratio of λC to λo when λC is defined as the central stretch ratio, which is generally estimated at the observation point near the specimen center, and λo is defined as the exterior stretch ratio measured at the tensile point. All λo = 4.6 are used for comparison purposes.In addition to the clamping technique at (or near) the corner of the specimen, the number of clamping points along its edge also affects the deformation uniformity in the equibiaxial planar tension. The simulation of equibiaxial planar tension is carried out in three cases, each focusing on a square membrane with the same geometric dimensions of 100 mm × 100 mm × 1 mm: (1) two-corner-point-fixed tension with five clips along each edge; (2) single-corner-point tension with five clips along each edge and four clips at the corners; and (3) multi-corner-point tension with four additional clips added to each edge of the specimen based on the two-corner-point-fixed tension. The tensile efficiency The hyperelastic membrane FE model is meshed using three-dimensional eight-node hybrid solid elements (C3D8H), and the mesh seeding is controlled with an approximate global size and verified, resulting in a total of 2500 elements. A quarter of the specimen with symmetrical conditions in the left and lower planes is proposed to simulate the equibiaxial planar tension test for a typical square EAP membrane to reduce the computational cost of the provided FE model. The tension mode is also simplified to help in the convergence of the model for simulating practical equibiaxial tension tests. The ramp displacements are eventually applied to the distributed lines rather than the grippers .In the two-corner-point-fixed tension, the distance between two clamping points held on two perpendicular edges and close to the corner must remain constant during stretching a. The diΦDi) which is externally tangent to the punched holes, and the testing marks in S of equibiaxial radial tension isF is the sum of the radial tensile forces at each grip. In practice, a laser non-contacting extensometer can be used to measure the strain on the surface of the specimen away from the grips through two laser tags placed on the surface [To produce equibiaxial strain and determine the mechanical characteristics of a circular diaphragm specimen, the radial tensile test requires applying a uniform radial tensile force (or displacement) around the specimen c. In pra surface .Φ 75 mm × 1 mm, Di = 65 mm) and punched hole diameter (Φ 5 mm) but with 12, 16, and 24 cuts are chosen for modeling. Three-dimensional eight-node hybrid solid elements (C3D8H) are utilized to mesh the FE models. Similarly, to reduce the number of elements and simplify the computation, a 1/4-symmetric membrane specimen is taken for analysis, with the boundary conditions set to axis symmetry  are taken along the radial direction to record their positions during the inflation, and then the profile curves of the balloon can be obtained. By utilizing Equation (17) and the simulation position information for the observation points on the surface of the inflated balloon, the curvature radii can be calculated. To conveniently understand the profile deformation of the balloon at various pressures, the curvature radii are normalized by the radius of the point closest to the vertex (1 mm away from the symmetry axis), as shown in As can be seen from the figure, the curvature radius of the profile reduces progressively along the longitude, except for a tiny fluctuation at the beginning point caused by the simplified simulation model, and the discrepancy of the radii also dwindled as the inflation pressure increased. In S-λ curves are then compared to the results of theoretical calculations  are selected for analysis. Calculated ulations . From thHb of the upper flange and the diameter Db of the inflation hole  implies that the inflation pressure is inversely proportional to the inflated balloon’s radius of curvature. The curvature radius at the vertex of the small hole model is about 13.6 mm when The research investigation ends when the equibiaxial stretch ratio reaches approximately 1.9 due to convergence issues and error reporting in ABAQUS, resulting in a limited range of inflation that deviates from practical results. These issues are primarily caused by the material model and its parameters. Substituting the equibiaxial tensile stress from Equation (10) into Equation (18) givesR, λ, the equation has numerous theoretical solutions. Adkins et al. [Γ < 0.21, the local extreme points will appear in the pressure-deformation equation, and the extreme p is obtained when λ = 1.84. In the inflation tension simulation, a maximum equibiaxial stretch ratio λ of approximately 1.90 can be achieved, which is close to the theoretical value.The SEDF is expressed differently on the right side of Equation (21). Because the components s et al.  observedΓ = 0.0038, which conforms to the latter condition (Γ < 0.21), results in multiple deformation solutions at local extreme pressure and diverges in the simulation analysis. Therefore, when applying FE software to analyze the inflation deformation of hyperelastic EAP membranes, we should pay attention to the material model and its parameters, which will affect the analysis range of deformation.In this study, the Moony–Rivlin model is used to re-fit the nominal stress and stretch data that are obtained from Ogden material parameters  see Tab. Accordiλc of the section closest to the center can be employed to represent the specimen’s stretch ratio when establishing the S-λ relationship. The stretch ratios obtained from the observation points are then normalized using λc, i.e., λ/λc. As a result, The non-uniformity of deformation in the equibiaxial planar tension affects the precision of the derived stretch ratio, resulting in lowered experimental accuracy. Along the symmetry axis, a series of observation points are allocated, and their positions are stated as the ratio of their geometry position from the center to the length of the investigated specimen  to calculate the nominal stress. The  methods .S-λ curves derived from the three equibiaxial planar tension tests are consistent with the theoretical calculation in the figure, and the discrepancy grows slightly when the stretch ratio increases due to distortion. Because the overall deformation is relatively uniform, the simulation result in single-corner-point tension is the closest to the theoretical calculation, and the stress error is about 2.1% when λ = 4. Multi-point tension with two corner points fixed yields the best tensile efficiency, ηλ ≈ 98.1%, when λo = 4.6 due to the increased number of tensile points and sufficient deformation of the specimen. λ = 4) and tensile efficiency ηλ (when λo = 4.6) for three types of planar tension.The The Mises stress contour maps obtained from the radial tension simulations for three different types of specimens are presented in iD that is tangent to the punched hole are chosen. Likewise, each point’s position is expressed as a percentage of the total observation length (iD/2).To further investigate the homogeneity of the stretch ratios in radial tension, a number of observation points that are uniformly spaced along the symmetry axis from the center of the circular membrane to the circle λ/λC). The stretch ratio is uniform throughout the radial distance of about 80% from the center to the inner tangent circle Di, as indicated in λo = 4.5, the shrinkage in the specimen with 12 cuts approaches 8% . The stretch ratios are obtained from an observation point near the center, and the S-λ curves of the EAP membrane materials agree well with the theoretical calculation result. The more cuts there are, the more uniform the deformation of the specimen and the more accurate the S-λ curves. When λ = 4, the 24-cut specimen has the lowest stress error, less than 4% of the theoretical result.It can be seen from the figure that the ηλ (λo = 4.5), along with the corresponding stress errors (λ = 4).The “pull” effect on the center area of the specimen with fewer cuts becomes noteworthy due to high stress in the transition arc between the grips, resulting in increased tensile efficiency, where the stretch ratios of 12-cut and 16-cut specimens even exceed that from the gripping points. ηλ, although increasing the number of cuts can thin the stretch bands and reduce the tensile efficiency, decreasing the diameter of the punched hole can increase the stresses around the root of the cut, strengthen deformation, and increase the efficiency. The above two factors have a hedging effect on tensile efficiency.The punched hole at the end of the cut is utilized to reduce stress concentration and prevent rupture. As demonstrated in In this paper, FEM is utilized to model and validate three typical equibiaxial tension methods, and the influences of the apparatus structure and specimen geometry parameters on the test results are also analyzed. The following conclusions can be drawn:λ ≈ 1.9 under certain conditions.The sample point for calculating deformation in the inflation tension test should be positioned as close to the vertex of the balloon as possible, ensuring accurate results for the characteristic curve and expanding the effective experimental range. The structure dimensions of the test apparatus have minimal impact on the final test accuracy within the simulated deformation range, although the large inflation hole can reduce the required test pressure, whereas the tiny hole possesses a low deformation height. It is worth noting that the range of EAP simulation analysis can be influenced by the material model and its parameters, with a maximum limit of λ = 4. Increasing the tensile points can make the overall deformation of the specimen more sufficient, thus obtaining a higher tensile efficiency λη, which also helps to reduce the force error.Among the two equibiaxial planar tension methods proposed in this paper, the deformation in the single-corner-point tension exhibits a higher level of uniformity, and the characteristic curve obtained closely approximates the theoretically calculated result with a minimal stress error of 2.1% when In the radial tension test, a decrease in stress error is observed with an increase in the number of cuts and larger punched hole diameters. By utilizing a 24-cut specimen with a punched hole diameter of 5 mm, it is possible to achieve a minimal stress error of approximately 3.83%. Increasing the diameter of the punched hole will reduce the stress in the transition arc between cut edges. However, employing a larger hole with more cuts results in a smaller stretch band, leading to severe tensile deformation and strength failure of the membrane. Additionally, excessive cuts may pose fabrication challenges. It should be noted that excessive deformation of the stretch band can lead to reduced tensile efficiency; however, this effect can be mitigated by increasing the number of cuts and reducing the diameter of punched holes on specimens.The conclusions derived in this paper can provide a useful guide for choosing an equibiaxial tension test method, designing an apparatus or specimen geometry, and evaluating the accuracy of the experiment. Although this paper focuses on the three typical equibiaxial tension methods, it can easily be extrapolated to other equibiaxial tension tests.


Multifocal glasses are a new type of lens that can fit both nearsighted and farsighted vision on the same lens. This property allows the glass to have various curvatures in distinct regions within the glass during the grinding process. However, when the curvature varies irregularly, the glass is prone to optical deformation during imaging. Most of the previous studies on imaging deformation focus on the deformation correction of optical lenses. Consequently, this research uses an automatic deformation defect detection system for multifocal glasses to replace professional assessors. To quantify the grade of deformation of curved multifocal glasses, we first digitally imaged a pattern of concentric circles through a test glass to generate an imaged image of the glass. Second, we preprocess the image to enhance the clarity of the concentric circles’ appearance. A centroid-radius model is used to represent the form variation properties of every circle in the processed image. Third, the deviation of the centroid radius for detecting deformation defects is found by a slight deviation control scheme, and we gain a difference image indicating the detected deformed regions after comparing it with the norm pattern. Fourth, based on the deformation measure and occurrence location of multifocal glasses, we build fuzzy membership functions and inference regulations to quantify the deformation’s severity. Finally, a mixed model incorporating a network-based fuzzy inference and a genetic algorithm is applied to determine a quality grade for the deformation severity of detected defects. Testing outcomes show that the proposed methods attain a 94% accuracy rate of the quality levels for deformation severity, an 81% recall rate of deformation defects, and an 11% false positive rate for multifocal glass detection. This research contributes solutions to the problems of imaging deformation inspection and provides computer-aided systems for determining quality levels that meet the demands of inspection and quality control. Curved components can often meet a wide range of structural requirements because they allow greater geometric freedom in design. They can establish the general look and feel of the design . ComponeMultifocal glasses are a new type of lens that can fit both nearsighted and farsighted vision on the same lens. This property allows the glass to have various curvatures in distinct regions within the glass during the grinding process. However, the disadvantage of multifocal glasses is that when the curvature changes abnormally, the glasses are prone to optical deformation during imaging. Because the glasses are utilized to directly envelop the eyes of the user, the deformation of the glass will cause imaging errors, which will bring trouble or even danger to the daily activities of the user. For example, dizziness may occur when going downstairs, or the inability to correctly decide the location between steps may be hazardous for the person. Progressive multifocal glasses allow people with myopia and presbyopia to easily and effectively improve their vision ,5. The pAlthough the blind spot location is usually not larger than in the other areas, the use of this area is very important and requires special inspection. At present, the degree of deformation of the blind area is inspected by inspectors operating manual instruments. Since imaging deformation has no regular form and clear borders, it is frequently difficult to identify and quantify, particularly on curved multifocal glasses. Furthermore, outwardly curved glasses tend to hinder the identification of deformation defects in multifocal glasses due to their high transmittance and reflectivity. This study develops an optical inspection system to quickly inspect and classify deformation defects in multifocal glasses to replace professional assessors.The rest of the article is composed as follows. First, we review the articles on the current techniques used by visual inspection systems for transparent products. Second, we describe the proposed image procedures to detect imaging deformation defects and determine the quality level of multifocal glasses. Third, we conduct tests and assess the performance of the suggested approach and traditional techniques. Finally, we conclude the contributions and indicate further directions.Automated visual inspection (AVI) is a crucial step in quality assessment for production processes as it assures high quality and enhances productivity by rigorously examining and evaluating all products in an industrial process ,7. The AImage deformation caused by perspective requires image correction before further image processing . In prevTransmission deformation refers to the image quality degradation of an observed object due to refractive media. Previous studies on deformation detection via the transmission of industrial components include Dixon  who desiGlasses are wearable products that are closely related to human daily activities and require strict testing and verification. If the eyeglass lenses have excessive defects, the user’s safety will be compromised. Wang et al.  performeCurrently, most optical inspection systems for transparent glass products mainly detect surface defects and do not identify imaging deformation defects. The imaging deformation defects in curved glass surfaces are highly transmissive and reflective and are difficult to accurately detect . Most ofThis study presents an optical inspection system with familiar norm patterns of image capture and employs a slight deviation control scheme to check for deformation defects, and a mixed intelligent model incorporating a genetic algorithm and a network-based fuzzy inference system to decide the grade of deformation severity of the multifocal glasses. To measure the grade of deformation of a multifocal glass, we first digitally imaged a pattern of concentric circles through a test glass to generate an imaged image of the glass deformation. This deformation image is examined to investigate the deformation’s presence and the defects’ location. Secondly, the imaged image is preprocessed to enhance the clarity of the concentric circles’ appearance. A centroid-radius model is adopted to represent the form variation properties of every concentric circle in the processed image. Thirdly, by looking for small changes in characteristic distance deviations to detect deformation defects through a slight deviation control scheme, a difference image showing the detected deformation defects can be obtained. Fourthly, according to the deformation measurements and locations that occurred during the training phase, the deformation’s fuzzy membership functions and inference rule sets are established. Finally, a mixed model incorporating a genetic algorithm and a fuzzy inference model is adopted to judge the grade in the deformation severity of the detected deformation defects. The adopted test samples are 6.0 mm thick and 48.4 mm in diameter and are arbitrarily drawn from the production line of a multifocal glass producer. In order to capture digital imaging images of norm patterns by testing samples to create imaging deformation maps of samples, this work suggests an imaging acquisition device using a concentric circular pattern for imaging image extraction. When using coordinates for image feature processing, some problems arise. When the image is translated, zoomed, or rotated, the judgment result will be erroneous due to the coordinate changes. Hence, it should be depicted by geometric properties. We use the centroid-radius model  to repre0, y0) and the s-th boundary point . The distances to the u-th circle in the concentric circular pattern are:We use the commonly used concentric circular pattern, which consists of eight concentric circles. The centroid radius u-th concentric circle can yield a distance vector For this pattern of concentric circles, many centroid radii of the Due to scale and rotation invariance, we normalize the distance vector u-th circle to the circle’s centroid and normalizing it to a vector When calculating the distances of centroid radii from the The distance feature vectors of all complete concentric circles in a test image are contrasted with those of the defect-free image, and the distance deviations of the respective edge points are measured to locate potential deformations in the test image. To detect slight deviations in distance variations, we propose a slight deviation control scheme, the exponentially weighted moving average (EWMA) scheme, which is usually applied in statistical process control ,32. We as-th sample point is defined as:UCL) and the control limit of lower bound (LCL) for the EWMA scheme are expressed as [The EWMA scheme is also a good option to detect slight drifts ,34. The essed as :(5)UCLs=L) and the value of constant weight The parameter designs of the chart are the multiple of the standard deviation e schema ,36. FiguThis research applies a fuzzy-related model to automatically detect changes in deformation severity . The genx, y) coordinates of the s-th edge point in a test image, x, y) coordinates of the s-th edge point in the concentric circular pattern image.By contrasting the detected deformation defect image with the concentric circular pattern image, σ is the standard deviation and c is the center point of the Gaussian membership function.The main purpose of the FIS model is not only to transform the measured values into fuzzy membership functions but also to set up fuzzy inference regulations and modes ,39. Its 1, U2, and U3, are the deformation levels of the zones A, B, and C, respectively, and the outputs are deformation levels. For example, while the deformation measure U1 of zone A is small (A1) and the deformation measure U2 of zone B is small (B1) and the deformation measure U3 of zone C is small (C1), the severity of the output Y is a slight distortion (Y1). A fuzzy regulation base containing eighteen regulations is created in this experiment.When the fuzzy membership functions have been set up, the fuzzy regulation base could be created based on the allowance of the deformation level of the multifocal glass. The closer the deformation defect occurs to the middle of the glass, the smaller the allowed allowance is, and the degree of deformation is severe. The closer the deformation flaw region is to the glass boundary, the higher the tolerance is allowed and is then categorized as slight on the deformation level. The fuzzy regulations are created according to the empirical regulations of experts. Three inputs, UWe use the TSK (Takagi–Sugeno–Kang) fuzzy model  as an inANFIS model is mostly a network-based fuzzy inference model set up by merging the concepts of fuzzy theory and neural networks ,41. It iGenetic algorithm mostly uses the procedure of reproduction and inheritance of organisms by means of mutation and crossover of chromosomes. Firstly, the original population of the GA is established by using the membership function parameters of the deformation measures, and the fitness values of each parameter combination are evaluated. The parameters of every parameter combination are then uniformly crossed and mutated, resulting in more diverse parameter values. The merit of this arithmetic is that it could be upgraded from a local optimal answer to a globally optimal solution by a mutation function.When a fuzzy inference system is created, it consists of membership functions of the three zones of deformations, the regulation set, and the inference module. The GA-based ANFIS method primarily optimizes the arithmetic in two stages ,43. The To confirm the capabilities of the proposed approach using concentric circular patterns, the performances of these recommended techniques are assessed on 550 sample images (350 training images and 200 test images) with different degrees of deformation. Each captured image has a size of 256 × 256 pixels, and each pixel contains 8 bits of gray scale. The algorithm of the realized deformation defect detection system is edited on the MATLAB application software platform, and implemented on the MATLAB R2013 version on the desktop . In this study, experimentally detected images are compared for correctness with manually labeled images. In terms of checking deformation defects, recall, precision, and accuracy are adopted as performance evaluation metrics for the proposed models. When the above performance indices are higher, the inspection performance is better. The recall rate is the regions of correctly identified true defects  divided by the regions of correctly identified true defects (TP) plus the regions of true defects incorrectly labeled as non-defects . It can be thought of as the fraction of true defects that are correctly identified in the set of all real defects. The precision rate is the regions of exactly identified true defects (TP) divided by the regions of correctly identified true defects (TP) plus the regions of non-defects incorrectly labeled as defects . It can be thought of as the fraction of these detected defects that are real defects. The accuracy rate is the regions of exactly identified true defects (TP) and the regions of correctly labeled true non-defects (TN) divided by the total regions of a testing instance (TP + TN + FP + FN). It represents the rate of correctly identified defects and non-defects over the total region of a testing image. If the dataset is imbalanced (both defect and non-defect classes have significantly different regions of testing images), the accuracy rate is not a good metric ,45.In terms of determining the deformation quality level, the accuracy rate is modified from individual deformation defects to a performance evaluation index with individual images as the basic unit. The detected deformations in an image are judged combinedly into three categories  by the GA-based ANFIS model and they are checked that each class is correctly classified. The accuracy rate is the number of test images categorized into the exact level class divided by the total number of test images.The size in pixel units of the line thickness of each circle on the concentric standard patterns influences the detection efficiency of the suggested approach for deformation defects. Smaller deformation defects will be more completely identified if an appropriate line thickness pixel size is chosen in the concentric standard pattern. We use a computer program to generate standard concentric patterns with different line thicknesses and then use these standard patterns with different line widths together with test samples to capture test images. We examine concentric circular patterns with line widths from 1 to 6 pixels in concentric circles by the suggested approach. In order to evaluate the inspection performance of multifocal glass deformation defects, To assess the performance of the classification of deformation defect severity in multifocal glasses, three classification models BPN , ANFIS, Using the method based on the Hough transform , two conThis study uses different parameter settings of the capture-related devices to take various test image sets and then select the test image set with the best defect detection effect. The parameter settings of this selected test image set are used as the standard for subsequent image acquisition. During the image acquisition process, the brightness of the acquired image is easily affected by the intensity of ambient light, which in turn affects the detection results. We investigate whether the detection results of the proposed method are susceptible to certain changes in image brightness to test the robustness of the method. In this study, the EWMA control scheme is applied to detect deformation defects, and the GA-based ANFIS method is adopted to categorize the severity of deformation defects. The performance evaluation results using different brightness variations are shown in The proposed concentric circular pattern outperforms the other two norm patterns in detecting slight to average deformations and small to medium area deformations. Therefore, the use of concentric circular patterns is more suitable for detecting deformation defects with less deformation in multifocal glasses. The main merit of this research method is to use the centroid radius descriptor to understand the deformation state of each edge point and use the EWMA control scheme to detect small deformations. In addition, using the GA-based ANFIS classifier model, the parameters that only converge in the local domain are extended to the global domain, which improves the classification effect.Since the proposed method is mainly established on extracting features from geometric properties for deformation detection, it is moderately sensitive to changes in illumination intensity. If the brightness variation range is within (μ ± 1σ) as a whole, it will have little effect on the detection results of this study. However, large changes in illumination can significantly increase grayscale variation, which in turn can significantly affect defect detection. To conquer the restrictions of the proposed method, it is suggested to update the statistics (mean and standard deviation) of the intensity in the training samples when the illumination changes significantly.This research presents a mixed approach constructed using computer vision and fuzzy theory techniques to detect deformation defects and decide the deformation level of multifocal glasses. It investigates the detection of imaging deformation defects in multifocal glass images and the classification of deformation severity. In this study, a vision system using concentric circular patterns for imaging is first developed to obtain test images showing imaging deformed areas and binarize and refine the circle edges in the image. If the boundary point-to-centroid distance value of the concentric circle goes beyond the upper or lower limit of the suggested EWMA scheme, it indicates that there is a deformation defect in this boundary point area. Then, through comparing the discovered defect image, the norm pattern is used to measure the amount of deformation. By partitioning the probable locations of defects into three zones of slight, average, and severe deformation, we summarize the individual deformation measures of the three zones. Finally, a GA-based ANFIS model is suggested to categorize the severity of multifocal glass deformation. The suggested approach is effective and efficient in detecting deformation defects and classifying the severity of deformed regions on multifocal glass images. Testing outcomes show that the proposed methods attain a 94% accuracy rate of deformation severity quality grades, an 81% recall rate of deformation defects, and an 11% false positive rate in multifocal glass deformation detection. Further studies can extend the proposed method to the problem of imaging deformation defect inspection of curved glass-related products, for example, the distortion detection of automobile windshields and the deformation detection of automobile rearview mirrors.


ACS Central Science, Thoreau et al. report a bioorthogonal chemical ligation techniqueto construct synthetic antibodies, dubbed SynAbs.1 The overall structure of SynAbs mimics the naturally occurringIgG, but they differ in one key aspect: unlike IgGs that specificallyrecognize only one epitope per antibody, SynAbs can be made to containtwo distinct antigen-binding sites, enabling them to bind two biologicaltargets at a time. In other words, they are bispecific.Antibodies, also known as immunoglobulins,are proteins secreted by immune cells to specifically bind foreignantigens, often from invading species. Immunoglobulin G (IgG), oneof the major classes of antibodies, is composed of two heavy chainsand two light chains that are interlinked via disulfide bonds, resultingin two identical fragment antigen-binding (Fab) domains for recognizingbiological targets, and one fragment crystallizable (Fc) domain thatmediates immune reaction and improves stability. In recent years,chemically producing and/or modifying antibodies for improved therapeuticfunctions have attracted attention across the fields of chemistryand medicine. In this issue of 2 However, many of these synthetic strategies areincapable of incorporating the Fc domain that could confer bsAbs withhigher stability, better solubility, longer half-life,3 and enhancement of tumor killing capacity due to Fc-mediatedantibody-dependent cell-mediated cytotoxicity (ADCC) and complementdependent cytotoxicity (CDC) effects.4 Existingmethods for producing Fc-containing IgG-like bsAbs are almost exclusivelyprotein bioengineering, including quadroma cell line technology,5 “knobs-into-holes”,6 CrossMab,7 etc. Despite greatprogress made by these strategies, bioengineering methods are oftenhampered by low yield, complicated purification processes, and lowmodularity.Bispecificantibodies (bsAbs) are attractive as they are capable of recruitingimmune cells to attack tumors or increasing binding specificity. Owingto recent advances in antibody conjugation methodologies, more than200 types of bsAbs have been made for clinical and preclinical trials.9 To construct IgG-like bsAbs, the authors started by producing HER2/HER2bivalent monospecific antibodies. After the site-selective disulfiderebridging reaction of CD20 Fc and HER2 Fab fragments, the duallyclickable-Fc and mono clickable-Fab could be generated to assembleFcCD20-(FabHER2)2 antibodies througha tetrazine-bicyclononyne (BCN) click reaction. The strategies describedby the authors achieved first-in-class purely chemical constructionof full IgG-like bivalent antibodies -FabCD3 construct. Incubatingthe resulting bispecific SynAb with T cells and epithelial carcinomaHCC1954 cells led to T cell activation and HCC1954 cell death, whichdemonstrates its capacity to recruit T cells to attack the targetcells.As a proof-of-concept demonstration, the HER2/CD3bispecific SynAb was used as a bispecific T cell engager (BiTE). TheFc domain of CD20 was functionalized using disulfide rebridging reagentswith two equivalent tetrazine handles, so the FabThe reported strategy is highly modular and easy to industrialize:both Fc and Fab fragments were obtained from commercial mAbs, andthe production of one SynAb was accomplished within 5 days with highyield. It is anticipated that this novel approach could be furtherapplied to generate an array of IgG-like antibodies for biomedicaland clinical investigations. Future improvement of the method couldbenefit from a greater choice of bioorthogonal chemical ligations.For example, if the disulfide rebridging reagents contained two distinctclick handles, antibody assembly processes could be well controlledin a more orthogonal manner. Additionally, the Fc domains could becarefully chosen and further modified to fully unlock the potentialof SynAbs, for example: (1) SynAbs containing an Fc domain are expectedto have a longer half-life, so introducing a suitable Fc domain tocurrently developed non-IgG bsAbs promises to increase their serumhalf-life. (2) Tumor killing capacity could be enhanced through Fc-mediatedADCC and CDC effects; this property could be utilized to improve therapeuticpotency. (3) The Fc domain could be further modified to generate antibody-drugconjugates for cancer treatment. (4) The click handle bearing theFc domain could be used as a platform to attach multiple molecules,such as cytokines or metabolites, for extended functionality. We expectthe functions of Fc-containing SynAbs will be fully exploited, andbioorthogonal chemical conjugation methods will drive technologicalprogress in immune therapy.