MET exon 14 splice-site mutations occur in ~3–4% of lung adenocarcinoma cases, defining a cohort of patients which might benefit from anti-MET targeted therapy. Such therapies have yielded mixed results, however, pointing to the need for better treatment design. Our study sought to aid this by characterizing key changes in mutant MET signaling behaviour. We first compared the transcriptional profiles of lung tumours with either METΔex14 or wild-type MET-amplification. METΔex14-mutant tumours exhibited increased activation of the Ras-MAPK pathway, consistent with our observations in an isogenic model system. Furthermore, sustained activity of this pathway is necessary for proliferation and maintenance of METΔex14 tumours, while forced reactivation of this pathway is sufficient to restore growth in the absence of MET activity. Our findings suggest that the MAPK pathway represents a main effector of METΔex14-driven cancer, lending credence to the possibility of combined MET-MAPK inhibition to improve therapeutic outcomes.MET exon 14-skipping (METΔex14)-driven lung cancers have generated some promising results but response rates remain below that seen for other kinase-driven cancers. One strategy for improving treatment outcomes is to employ rational combination therapies to enhance the suppression of tumour growth and delay or prevent the emergence of resistance. To this end, we profiled the transcriptomes of MET-addicted lung tumours and cell lines and identified the RAS-mitogen-activated protein kinase (MAPK) pathway as a critical effector required for METΔex14-dependent growth. Ectopic expression of MET in an isogenic cell line model showed that overexpression of the mutant MET receptor led to higher levels of MAPK phosphorylation and nuclear import, resulting in increased expression and phosphorylation of nuclear MAPK targets. In comparison, other known MET effectors were unaffected. Inhibition of this pathway by KRAS knockdown in MET-addicted cells in vitro led to decreased viability in only the METΔex14-mutant cells. Conversely, decoupling RAS-MAPK axis, but not other effector pathways, from MET activity via the introduction of constitutively active mutants conferred resistance to MET inhibitors in vitro. Our results suggest that aberrant hyperactivity of the MET receptor caused by the exon 14-skipping mutation does not uniformly upregulate all known downstream effectors, rather gaining a predilection for aberrantly activating and subsequently relying on the RAS-MAPK pathway. These findings provide a rationale for the co-targeting of the RAS-MAPK pathway alongside MET to prolong therapeutic response and circumvent resistance to improve patient survival.Targeted therapies for  EGFR . Blocked membranes were incubated with primary antibodies (listed below) overnight at 4 °C with shaking. Membranes were then washed 3× with TBS-T and incubated with the appropriate horseradish peroxidase-conjugated secondary antibody at 1:10,000 dilution for 1 h at room temperature. SuperSignal West Pico Plus Chemiluminescent Substrate  and SuperSignal West Femto Chemiluminescent Substrate  were used on the ChemiDocMP Gel Imaging System (Bio-Rad Laboratories) to visualise immunoblot bands. Band intensity was quantified by densitometry using ImageJ software and summarized in Cells were grown in 6-well, 6-cm, or 10-cm plates to 70–80% confluency. Prior to harvest, cells were washed with ice-cold PBS  and lysed with an appropriate volume of RIPA lysis buffer  containing Halt Protease and Phosphatase Inhibitor Mixture . Cells were harvested by scraping and were frozen overnight at −80 °C. All samples were sonicated, then cleared of cell debris via centrifugation at 15,000× v/v BSA in TBS-T prior to use. Primary antibodies were used at 1:1000 dilution, while secondary antibodies were used at 1:10,000 dilution. All antibodies except anti-ERM/ETV5  and anti-DUSP6  were purchased from Cell Signaling Technology : MET (8198S), p-MET Tyr1234 (3077S), p-MET Tyr1349 (3121S), AKT (4691S)), p-AKT Ser473 (4060L), p44/42 MAPK (137F5), p-p44/42 MAPK Thr202/Tyr204 (9101S), MEK1/2 (9122S), p-MEK1/2 Ser217/221 (9121S), STAT3 (12640S), p-STAT3 Y705 (9145S), SRC (2108S), p-SRC Y416 (59548S), Ras (8955S), cMYC (5605S), cFOS (2250S), p-cFOS S32 (5348S), FRA1 (5281S), p-FRA1 S265 (5841S), Vinculin (13901S), β-Actin HRP-linked (12620S), Histone H3 (4499S), Anti-Rabbit IgG HRP linked (7074S), and Anti-Mouse IgG HRP linked (7076S). MET kinase inhibitors crizotinib (PF-02341066), cabozantinib (BMS-907351), and capmatinib (INCB28060) were purchased from SelleckChem  and dissolved in DMSO  prior to use. Hepatocyte Growth Factor recombinant human protein (PHG0324) was purchased from Thermo Scientific and reconstituted according to manufacturer’s instruction prior to use.All antibodies used for Western blot analysis were diluted in 5% 6 pTRIPZ:shKRAS and pTRIPZ:shScrambled cells were injected subcutaneously into the left and right flanks of 8-week old male NRG mice (n = 16) in alternating fashion, with half the mice (n = 8) receiving H1993 cells and the other half receiving Hs746T cells. All mice were placed on doxycycline-infused feed  starting 4 days prior to injection and continuing for the duration of the study. Measurement of tumour size was performed using callipers on a biweekly basis. Tumour volume was estimated using the equation V = 0.5 L·W2 and final weights were determined at endpoint.All animal experiments were conducted in accordance with protocols approved by the University of British Columbia Animal Care Committee (UBC ACC). Cell lines used for the generation of tumour xenografts were as follows: H1993 pTRIPZ:shKRAS, H1993 pTRIPZ:shScrambled, Hs746T pTRIPZ:shKRAS, and Hs746T pTRIPZ:shScrambled. Immediately prior to injection, all cells were trypsinised, counted, and resuspended in an appropriate volume of ice-cold PBS. Moreover, 2 × 10MET occurs in a significant fraction of LUADs, yet it represents a poor candidate for targeted monotherapy in these cases owing to its co-occurrence with alterations in other oncogenes [MET exon 14-skipping mutations, as well as high-level amplification of the wild type MET gene, constitute true driver alterations, which confer sensitivity to anti-MET therapy in some instances. However, while both receptor amplification and mutations leading to exon 14 skipping can result in aberrant hyperactivity of MET, they differ in the mechanism by which they stimulate receptor activity. There is evidence which suggests this may lead to differences in terms of receptor localisation, recycling, and protein interactions [Overexpression or low-level amplification of ncogenes . In contractions . Thus, wMETΔex14-expressing cancer lines (Hs746T and H596) to another MET-addicted line with high-level amplification of the wild type MET gene (H1993). Notably, while all three lines exhibited a comparable degree of ERK1/2 (pERK1/2) and AKT (pAKT) phosphorylation at baseline, treatment with HGF to specifically stimulate MET activity resulted in a greater increase in phosphorylation of both RAS effectors in the METΔex14 lines compared to H1993 cells, suggesting that stimulation of METΔex14 may activate these pathways to a greater degree than the wild-type receptor  and METΔex14 (Hs746T) cells similarly reported higher ERK1/2 phosphorylation levels in Hs746T cells compared to EBC-1 [METΔex14-expressing cells exhibit higher levels of HGF-induced RAS pathway activity despite similar or lower levels of MET phosphorylation.To determine whether such differences exist, we compared the status of known MET effector pathways in receptor B. In conreceptor B. Furtheto EBC-1 . These rMETΔex14 and MET-amplified lines under conditions of MET stimulation, with a focus on the “Oncogenic Signatures” library of gene sets representing transcriptional signatures of cellular pathways known to be dysregulated in cancer . We repeated this analysis using the alternate “Hallmarks” library gene sets, and observed a similar result. These results suggest that, compared to cancers addicted to the wild type MET receptor, METΔex14-driven cells exhibit an expression signature more similar to KRAS-driven cancers. Given the lack of METΔex14 cell lines available, we expanded our analysis to include publicly available RNA-seq data [MET amplification (n = 6) or METΔex14 mutations (n = 8). In agreement with our cell line findings, GSEA results show a positive enrichment of KRAS-mediated gene sets in the transcriptomes of METΔex14-mutant tumours compared to those with high-grade wildtype MET amplification , DMSO (baseline), or HGF+cabozantinib (MET inhibitor). We compared expression profiles between each cell line and assessed the resulting differentially expressed genes using gene set enrichment analysis (GSEA) to identify transcriptional programs differentially regulated between n cancer C. This rseq data  from tumfication E. Gene Smparison F. Furthed YEATS4 ,46  and downregulated in response to cabozantinib treatment (Hs746T)  and H596 (36/200 hits) cells in response to HGF stimulation, compared to the H1993 MET-amplified cell line (20/200)   A. This oell line B. A para(20/200) C. Some oeration) D. Intereectively B; both gMET overexpression model system to directly compare the effects of wild type and mutant MET signaling on its downstream effectors. Using a doxycycline-inducible vector, we generated HEK293T cell lines expressing wild type MET, its oncogenic mutant isoform METΔex14, or GFP. Additionally, we further included a MET-Y1003F mutant isoform to investigate whether loss of the c-Cbl binding site encoded by exon 14 phenocopied loss of the exon in its entirety. We found that, despite similar levels of total MET protein across all three established cell lines after the addition of doxycycline, the METΔex14-expressing cells exhibited a notable increase in phosphorylation of its kinase domain (Y1234). By comparison, phosphorylation of this residue in both the wild type and Y1003F mutant MET receptors was significantly lower (MET or the MET Y1003F mutant (METΔex14 (Hs746T/H596) vs. wildtype MET-amplified (H1993) cells  cells A. Intere3) cells . This suMETΔex14-expressing cells  or non-targeting control (shSCRAMBLE) into Hs746T and H1993 cells, enabling us to conditionally knock down KRAS in these cells upon the addition of doxycycline. Induction of shKRAS with doxycycline led to suppression of total RAS protein in H1993 cells A. Howeve6T cells B. In con6T cells C. We att6T cells D–F, suggKRAS decoupled the RAS-MAPK pathway activity from the MET receptor, constituting the most common form of resistance against MET-targeted therapies in METΔex14-presenting tumours [G12DKRAS, p20-E545APIK3CA, and p20-A662C_N664CSTAT3). In H596 lung adenosquamous cells, which exhibit HGF-dependent growth reversible via MET inhibition, we found that doxycycline-induced expression of constitutively active mutant KRAS led to HGF-independent cell growth  to be a common form of acquired resistance [METΔexon14-mutant, but not MET-amplified, cells. By contrast, in vitro studies have identified alterations in MYC, mTOR, and PIK3CA, but notably rarely KRAS alterations, as potential drivers of resistance in MET-addicted cancer cells with MET-amp [The present study is aimed at facilitating the design of rational combinatorial therapies against METΔexon14-driven cancers, where response rates from single-treatment targeted therapies against MET alone remain largely mixed ,48,49,50 MET TKi . Alreadysistance ,25,54,55 MET-amp ,57,58.MET WT and METΔexon14 in human lung HPL1D cells led to similar levels of ERK1/2 phosphorylation , we nevertheless observed a markedly higher degree of pERK1/2 in the nuclear fractions of both cell lines. Consistent with these results, we also found higher levels of phosphorylated cFOS and FRA1, which together with FRA2 and c-JUN form the heterodimeric complex of AP1. Additionally, protein levels of ETV5, a key player in the maintenance of Ras-induced lung adenocarcinoma in alveolar type II cells [METΔexon14 compared to just ectopic MET WT overexpression. The oncogenic nature of MET exon14-skipping mutations would provide the most direct reason why METΔexon14 expression promotes greater increase in RAS-MAPK signaling compared to amplification of its wild type counterpart. However, high-grade amplification of wild type MET is also considered a driver alteration, such as in H1993 cells, and can be treated successfully in the clinic using anti-MET targeted therapies [The ERK1/2 serine-threonine protein kinases sit at the end of a multi-tiered phosphorylation cascade, beginning with KRAS-mediated activation of RAF-1 (MAP3K) and ending with their phosphorylation and nuclear translocation . This laII cells , were hiherapies ,62,63. FMETΔexon14-expressing cell lines in response to HGF.One possible reason may be due to a critical importance of the juxtamembrane (JM) domain in regulating the balance between receptor recycling and degradation pathways. Rapid receptor internalisation following activation is a key mechanism by which cells rapidly switch off signaling to prevent sustained receptor activity, hence the oncogenic effects of losing this domain . HoweverIn addition to spatiotemporal regulation of MET signaling, its pleiotropic behaviour is tightly controlled through a plethora of binding partners, including adaptor proteins GRB2, CRK, and SHC, as well as the scaffolding protein GAB1 . Site-spTo our knowledge, there have been no studies examining the direct molecular consequences of losing the JM domain in its entirety, though the MET Y1003 phosphotyrosine site within this domain has been identified to be functionally indispensable for mediating receptor degradation via its recruitment of the E3 ubiquitin ligase c-CBL . On thisMET appears to be reliant on activation of a more diverse complement of effector signaling pathways to drive tumourigenesis, potentially requiring a more personalised treatment approach. Additional studies comparing molecular mechanisms of MET hyperactivity will be required to fully understand the oncogenic nature of MET exon 14-skipping mutations and aid in the design of rational combinatorial therapies to combat drug resistance and improve treatment outcomes.In summary, our report highlights distinct signaling and transcriptional properties elicited by different oncogenic driver alterations affecting MET. In the case of exon 14-skipping mutations, growth and survival advantages are conferred mainly through the RAS-MAPK pathway. This hallmark represents a potential point of weakness exploitable by vertical MET + MEK or MET + ERK inhibition, a strategy that was successfully deployed in EML4-ALK-positive LUADs. By comparison, high-grade amplification of wild-type


Some reinforced concrete structures must be repaired at an early stage in their life due to the oxidation processes suffered by their reinforcements; such processes involve serious pathologies that affect the stability and safety of buildings. Spanish legislation distinguishes several classes of environments, with non-aggressive and normal exposure providing a longer useful life of the structure. The present study shows that some structural elements in reinforced concrete, mainly the pillars in the area of contact with the ground, are exposed to significant corrosion by carbonation. This position of the structural elements dramatically and abruptly shortens the useful life of the models provided for the current regulations. A total of 17 pillars in 10 buildings of different ages and locations in the Spanish Mediterranean area, not subject to the presence of chlorides, have been analyzed. These buildings are situated in environments considered by the standard as normal and non-aggressive. The actual carbonation that these elements present have been compared with that which can be derived from the model established by Spanish regulations. Of these pillars, 14 present a carbonation higher than that derived from the model, and the last three pillars largely conform to the figures of the model. This significant deviation shows the need for a revision of the Spanish EHE 08 regulation, which should include aspects such as the action of dampness by capillarity and the differences in electrochemical potential between the different materials. One of the most frequent pathologies in reinforced concrete is the corrosion of the reinforcements. A large part of the residential buildings in Spain and in many other developed countries includes reinforced concrete structures that are regulated by specific regulations, which, in most cases, require a building life greater than or equal to 50 years. The extensive use of concrete throughout the 20th century has increased the levels of definition  and quality control in its manufacturing and implementation. For two millennia, the concrete prepared by the Romans using lime, pozzolana and aggregates has survived the natural elements and external actions, proving its durability. With the use of concrete, one has the idea of a very durable material, given its stone-like characteristics and mechanical qualities. Concrete guarantees a very suitable medium for the protection of reinforcements thanks to its high alkalinity (pH = 12–13), acting as a chemical barrier, and the physical barrier that it provides.However, under aggressive conditions  ,5,6,7,8,The standards and instructions for the preparation of reinforced concrete consider several general classes of exposure related to the corrosion of reinforcements: non-aggressive, normal, marine and with chlorides other than the marine environment. In non-aggressive environments (interiors of buildings) and normal environments , the prediction models for the useful life of the structure give very high figures, in the order of more than 100 years.However, there are numerous cases of premature reinforcement corrosion in reinforced concrete elements in these types of environments with a low level of aggressiveness. Therefore, there is a need to analyze the conditions existing in each one of them in order to determine the common factors that may contribute to the corrosion and which are not currently considered by the regulations since the predictions made using the corresponding models are so inaccurate. In these environments with no or low levels of chlorides, the initiation and propagation of steel corrosion in reinforced concrete can only occur due to carbonation in the rebar coating.2 or μA/cm2. In the case of steel, 1 mA/m2 or 0.1 μA/cm2 corresponds to a mass loss of approximately 90 g/m2/year and a penetration rate of approximately 11.7 μm/year. The corrosion rate can be considered negligible if it is below 0.1 μA/cm2, low if it is between 0.1 and 0.2 μA/cm2, moderate between 0.2 and 1 μA/cm2 and high if it is between 1 and 100 μA/cm2 according to the RILEM   and is measured in μm/year. Often, especially in laboratory tests, it is expressed in electrochemical units as mA/muctures) .2 (HA-25) for concrete in reinforced concrete elements. The general classes of exposure are: non-aggressive (I), normal , Marine , and with chlorides not originating from the marine environment (IV). In addition, there are other specific classes of exposure: Aggressive chemical , with frost  and Erosion (E). However, the general exposure classes are I (Non-aggressive) and II , which, in the absence of aggressive agents, should provide a longer useful life according to the current EHE models . In. Ini = xOnce the carbonation front has reached the reinforcement, the steel depassivates and corrosion can take place if oxygen and water are present. There is always a sufficient amount of oxygen that reaches the surface of the steel to allow the corrosion process. In this case, the corrosion rate is governed by the resistivity of the concrete .Moisture content is the main factor determining the resistivity of carbonated concrete. Second, the microstructure of the concrete and the factors that determine it  are also important for the carbonation rate and initiation time. The corrosion rate can be considered negligible, except for high humidity, or when the duration and frequency of the periods of water condensation on the concrete surface can cause variations in the moisture content at the level of the reinforcement.The situation is much more serious than that described above if there are chlorides present in the concrete , even inIn the cases studied, the existence of chlorides is negligible, and the corrosion rates contained in the standard model were considered .Ttx = depth of concrete considered (reinforcement cover) in mm∅ = reinforcement diameter in mmVThe formula that includes the propagation time model according to point 1.2.3. of Annex 9 of EHE  models tCorrosion rates were not measured, but in the absence of experimental data, 2 μm/year  had been calculated according to the EHE model in each of the cases, the sum of the total time of the two periods in the case of corrosion by carbonation would be: T = tThis working method incorporates all the data of each of the elements analyzed in the buildings in the sample and the models of the initiation times tstandard .i) of the reinforcement coating and the expected useful life of each column analyzed from the position of its reinforcements (initiation time + corrosion propagation time), as well as the useful life model results (T = ti + tp). From the models (functions), we know the theoretical carbonation time  and the total useful life (initiation plus propagation) using the GeoGebra Classic 5 program.The results are the intersection points of the function with the position of the reinforcing bars (covering).This study processes each of the elements, for the initiation states (function of the blue curve) and the total time for the attack by carbonation for corrosion (function of the red curve), and offers us the results of the period (years) necessary to reach the carbonation of the entire coating (x in blue on the reinforcement) or the expected useful life of each analyzed element (x in red on the reinforcement) according to the theoretical models for the stirrups ; longituThe study also recorded the depth of carbonation in the concrete corresponding to the age at which the test was carried out. Once the mathematical expression of the corrosion initiation model is known, and taking advantage of the graphical analysis of each pillar studied, the carbonation depth corresponding to its age can be calculated, and thus it is possible to compare the result of the theoretical model  with the real depth obtained in the phenolphthalein test  of the 17 pillars in the 10 different buildings .The results obtained from the depths of carbonation are provided in order to carry out a comparative study of the models and reality. The characteristic resistances of the 17 studied pillars are shown and the results are presented in order, from the lowest f52.39 mm .These results show a correspondence between the carbonation depth and the concrete strengths obtained, confirming that the carbonation depth decreases with increasing fThe depths of carbonation obtained in reality are, in most cases, greater than the depths of carbonation resulting from the application of the standard model.Another result to consider and discuss occurred in the pillars with the highest resistance, of more than 30 KN/mmFor the discussion of the data obtained in the corrosion initiation and propagation models, the useful life of the element is considered, analyzing the data in longitudinal reinforcements, where carbonation (initiation) arrives later due to a thicker coating than in the stirrups , but the propagation of corrosion progresses more quickly since it depends on the reinforcement’s diameter and it has a larger section ∅. Furthermore, in most cases, the most obvious pathologies originate from the oxidation of the main reinforcements, producing cracks up to the concrete surface parallel to its trajectory. That is why the results in The data are presented in order from lowest to highest characteristic strength . The resAs the strength of the concrete increases , the difIn The processes of corrosion of the reinforcements in reinforced concrete are very complex, and their analysis can be undertaken from the application of the mathematical models offered by the regulations. They have been studied in 10 residential buildings in non-aggressive and normal environments, and in the verified absence of chlorides, with the structural elements only being exposed to corrosion by carbonation. All the cases studied are centered on reinforced concrete pillars on the lower floors of the building and in which corrosion of the reinforcements had occurred with evident pathology . The structures cannot be considered old since none of the buildings was more than 50 years old, which is less than the minimum useful life that a residential building should have.The studies of the depth of carbonation reflect a behavior that is clearly related in a linear way: as the strength of the concrete increases, the depth of carbonation decreases. However, this carbonation is much higher than that estimated by the standard models for the environments studied, in some cases by around 300%. Only in three of the seventeen cases was the extent of carbonation similar to that expected, and, in six of the most resistant concretes, the depth of carbonation was less than the thickness of the coatings of the reinforcements. Despite this, all the elements studied had been attacked by corrosion of the reinforcements. This indicates the difficulty in understanding the process and alerts us to the existence of other oxidation mechanisms that can cause a galvanic cell in the Fe or reinforcement that releases ferrous and ferric ions, or even to other types of oxidation generated by other electrolytic processes, which opens up a new field of research. Two possible causes are considered:(a) In the cases of higher levels of carbonation, different levels of humidity were detected between the lower part  and the upper part of the element. The standard models do not consider this fact, and this suggests an area that could be explored.(b) In the cases of lower levels of carbonation (corresponding to higher characteristic strength), there were no appreciable differences in humidity, so the causes can be attributed to a different electrochemical potential between products at the top and bottom of the pillar.Regardless of the differences in the real age, there is a clear and evident shortening of the useful life of the element, compared with the model that results from the application of the standard (the initiation and propagation periods of corrosion decrease). This situation is the consequence of an unexpected increase in the depth of carbonation in most cases, and in other cases, it is caused by processes that are independent of the alkalinity of the medium and which are presumably produced by other electrochemical processes. We can conclude that the Spanish standard EHE 08 needs a thorough revision, which should include other variables related to corrosion processes in the models for obtaining corrosion initiation and propagation periods. Among other factors, it is necessary to consider the humidity caused by capillarity and the differences in electrochemical potential between materials and different construction systems.


The resulting modified GO, that was DDM−GO@SiO2. The study found that DDM−GO@SiO2 showed good dispersion and compatibility with thermoplastic polyurethane (TPU) substrates. Compared with pure TPU, the tensile strength of the TPU composites increased by 41% to 94.6 MPa at only 0.5 wt% DDM−GO@SiO2. In addition, even when a small amount of DDM−GO@SiO2 was added, the UV absorption of TPU composites increased significantly, TPU composites can achieve a UV shielding efficiency of 95.21% in the UV-A region. These results show that this type of material holds great promise for the preparation of functional coatings and film materials with high strength and weather resistance.This study prepared 4,4-diaminodiphenylmethane (DDM)-functionalized graphene oxide (GO)@silica dioxide (SiO Yu et al. [2 composites by in situ preparation and introduced the hybrid nanoparticles into epoxy resins. They found that the unique 3D structure of graphene/SiO2 increases the interfacial adhesion between the filler and the matrix and significantly improves the mechanical properties of the epoxy resins. SiO2/GO nanocomposites not only improve the mechanical properties of the polymer but also protect against UV light. The conjugated groups and aromatic structures on the surface of GO provide good absorption of UV light [2 can reflect UV light [Thermoplastic polyurethane (TPU) is a multi-segment copolymer consisting of hard and soft segments . It is a and TPU . Kim et  and TPU  attachedu et al.  obtainedUV light , whereasUV light  and can 2 nanocomposites were obtained by the hydrophobic modification of GO using 4,4-diaminodiphenylmethane (DDM) and in situ chemical growth of SiO2 nanocomposites on DDM−GO by using potassium silicate water glass. DDM−GO@SiO2 was dispersed into TPU by solution blending. DDM−GO@SiO2 was successfully characterized using scanning electron microscopy (SEM), infrared (IR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and other methods. The effects of different additions of DDM−GO@SiO2 on the mechanical properties and UV shielding properties of TPU were also focused on.This study proposed a simple and environment-friendly method. DDM−GO@SiON-dimethylformamide (DMF), ethyl alcohol, and sodium dodecyl benzene sulfonate (SDBS) were obtained from Sinopharm Chemical Reagent Co., Ltd., Shanghai, China. Hydrochloric acid with an HCl content of 37.5% was purchased from Jia Ni Chemical Co., Ltd., Jiangsu, China. These reagents are of analytical grade. TPU (WHT-1195) was acquired from Wan Hua Chemical Group Co., Ltd., Hubei, China. Potassium silicate was supplied by Usolf Chemical Tech., Inc, Shandong, China. Deionized water was homemade and then used for all experimental procedures.GO was supplied by Tan Feng Tech., Inc, Jiangsu, China. DDM, ammonium hydroxide, N, 1.5 g of DDM was added at 95 °C to 300 mL of deionised water sonicated with 0.5 g of GO. The mixture was magnetically stirred at 95 °C for 10 h and then DDM−GO was obtained by vacuum filtration of the mixture several times using deionized water and freeze-dried.2 composites were obtained by vacuum filtration of the mixture several times using deionized water and freeze-dried.3.0 g potassium silicate was added to 50 mL of deionised water sonicated with 0.5 g DDM−GO and 0.2 g SDBS. The pH of the mixture was adjusted to 7 by hydrochloric acid in an ice water bath and maintained for 12 h. Lastly, DDM−GO@SiO2 composites were added to 100 mL of DMF, ultrasonically dispersed for 20 min, and then heated to 80 °C. TPU (10.0 g) was dissolved into the dispersion, stirred at high speed for 4 h, placed in a mold, and de-bubbled in a vacuum drying oven at 80 °C. Then, the DMF was dried out to prepare DDM−GO@SiO2/TPU composites. DDM−GO@SiO2 nanocomposites were filled with 0, 0.1, 0.3, 0.5, 1, and 2 wt% of the total TPU and denoted as S0, S1, S2, S3, S4, and S5, respectively. 2/TPU composites.DDM−GO@SiOCharacteristic peaks of the material were analyzed via Fourier-transform infrared (FT-IR) spectroscopy . The crystal structure of the material was characterized using XRD  with a scanning diffraction angle of 5°–80° and a step size of 5°/min. The chemical composition of the material was determined with XPS . Bond and structural defects of the material were analyzed using Raman spectroscopy  at a wavelength of 532 nm. The microstructure of the material was examined via SEM  operating at 10 kV, and local elemental analysis was performed via energy dispersive spectroscopy  at 20 kV. Cross-sectional scanning of the TPU composites was brittle broke in liquid nitrogen. The specimens were subjected to tensile tests using GB/T 528-2009. The testing apparatus was a universal testing machine . Absorbance and transmittance of the materials were tested on a UV-VIS-NIR spectrophotometer .2 particles. The FT-IR spectrum of GO demonstrates O–H vibration, C=O vibration, C=C stretching vibration, C–H vibration, and C–O stretching vibration peaks at 3406, 1723, 1626, 2923, and 1069 cm−1, respectively [−1 is the stretching vibration of C–N [−1 because of p–π conjugation [2 at 800 and 477 cm−1, respectively, are consistent with the characteristic peaks of SiO2 [−1, and O–H presents a lower peak intensity compared with DDM−GO possibly because of the reaction of the hydroxyl group on the surface of DDM−GO with Si–OH on the surface of SiO2 to generate Si–O–C via dehydration [2 on the surface of DDM−GO.ectively . The FT-jugation . These r of SiO2 . The Si–2 to assess whether or not the modification was successful. The total XPS spectrum of DDM−GO@SiO2 in 2 graft on the DDM−GO surface. XPS tests were performed on DDM−GO@SiO2 were illustrated in 2 shows a broad peak at 2θ = 22.7°, which corresponding to the (111) crystal plane of SiO2 nanoparticles. This result suggests that the SiO2 particles cover the layered GO sheets successfully.XRD spectra of GO, DDM−GO and DDM−GO@SiO2 show two distinctive peaks attributed to the G and D bands. The G band, which represents the E2g vibrational mode of first-order scattering and is used to characterize the sp2 bond structure of carbon, appeared at 1591 cm−1. The D band, which is a reflection of the disorder of the crystalline structure, appeared at 1347 cm−1 [D/IG) intensity is an indicator of the extent of surface defects in carbon materials. The increment in D peak intensity implies the broken sp2 bonds and the presence of more sp3 bonds on the sheets. As shown in D/IG ratio was calculated to be 0.84 for GO, 0.94 for DDM−GO, and 1.15 for DDM−GO@SiO2. The higher ID/IG value of DDM−GO than GO is due to the reaction of DDM with oxygen-containing groups on the GO surface, resulting in more surface defects after GO deoxidation. Meanwhile, the higher ID/IG value of DDM−GO@SiO2 than DDM−GO indicates the increased disorder caused by the grafting of SiO2 onto DDM−GO. The results are similar to the study of Kou [Raman spectra of GO, DDM−GO, and DDM−GO@SiO347 cm−1 . The raty of Kou .2 were analyzed through SEM. 2 is rougher than that of DDM−GO with many attached SiO2 particles. By contrast, the morphology of DDM−GO@SiO2 is similar to that of GO modified with a tetraethylsilicate mixture [2 on DDM−GO. Successful modification of GO by DDM was further demonstrated due to the presence of N elemental. It can be seen that Si element is evenly distributed in the system, which shows that SiO2 is well dispersed in DDM−GO.Microscopic morphologies of GO, DDM−GO, and DDM−GO@SiO mixture . The EDS2 content on the mechanical properties of the nanocomposites. Stress–strain curves and the corresponding tensile strength and elongation at break of the TPU composites with different DDM−GO@SiO2 fillings were shown in 2 filling content increased by 41% to 94.6 MPa. The significant increase in tensile strength can be attributed to the increased forces between DDM−GO@SiO2 and TPU. However, the tensile strength of the nanocomposites gradually decreased as the content of DDM−GO@SiO2 exceeded 0.5 wt% The elongation at break also decreased with increasing DDM−GO@SiO2 content. This phenomenon can be explained by the fact that the degree of deformation of the TPU molecular chains is limited at high DDM−GO@SiO2 loadings, leading to a reduction in the strain at break. Furthermore, a high amount of DDM−GO@SiO2 may lead to aggregation in the TPU matrix and induce the formation of defects, leading to a decline in mechanical properties [2 and TPU were characterised by FT-IR tests. As shown in 2, the N-H stretching vibration peak of the TPU composite blue shifts from 3331 cm−1 to 3333 cm−1, which is attributed to the addition of the filler breaking the hydrogen bond within the TPU and forming a stronger hydrogen bond between the filler and TPU matrix. The hydrogen bond between DDM−GO@SiO2 and TPU is shown schematically in −1 and 1703 cm−1 correspond to “free” C=O and bonded C=O in TPU, respectively. For every N-H bond created between DDM−GO@SiO2 and TPU, a new “free” C=O is formed [2 and TPU, the trend also corresponds to the change in mechanical properties.The stress–strain analysis was used to investigate the mechanical properties of TPU and the effect of DDM−GO@SiOoperties . The strs formed . A Gausss formed , indicat2 contents from 0.1 wt% to 2 wt%, were obtained to analyze the UV-shielding performance of the DDM−GO@SiO2/TPU nanocomposites over the entire UV range. 2 and TPU [2 is observed at a peak of 380 nm. The introduction of DDM−GO@SiO2 increases the absorbance of TPU within the entire UV region (200–400 nm), and the absorbance increases gradually with increasing content. As shown in 2 content. This result is due to the reflection of UV light by SiO2 and the strong absorption of incident UV light by the GO sheet layer, thus protecting the internal structure of TPU. The relevant schematic is shown in 2/TPU nanocomposites. The blocking efficiency at given UV ranges can be calculated using the following equations [The transmittance and absorbance spectra of samples, including pure TPU and TPU nanocomposites with different DDM−GO@SiO and TPU . The absquations :(1)UV-A 2 improves the UV shielding efficiency in the UV-A and UV-B regions, especially in the UV-A region, which is the most serious for TPU UV aging. When the content of DDM−GO@SiO2 is 2 wt%, the shielding efficiency can reach 95.21% from 79.25% of pure TPU. The specific data are shown in As shown in 2 in TPU. Wavy and relatively smooth cross-sectional morphology is observed in pure TPU, as shown in 2. As the loading of DDM−GO@SiO2 increased above 1 wt%, significant agglomeration and cracks occur in the cross section of the TPU composites (2 filling because of the agglomeration of the filler in TPU and the decrease in the interfacial bonding force. It is completely pulled out during the tensile process. The higher magnification SEM image and EDS spectra of the circular area of the 0.5 wt% DDM−GO@SiO2/TPU composite are shown in The cross-sectional morphology of the polymer was characterized using SEM to investigate the dispersion and interfacial interaction of DDM−GO@SiOmposites e,f. Many2 nanocomposites were obtained by depositing nano-SiO2 on the surface of DDM−GO by in situ growth. The introduction of nano-SiO2 provides non-covalent attachment points and further improves DDM−GO physical entanglement with TPU. Meanwhile, DDM−GO and SiO2 have a synergistic effect in reinforcing and shielding UV light. TPU composites with different DDM−GO@SiO2 contents were prepared by solution blending. Compared with that of pure TPU, the tensile strength of the TPU composites with a filling amount of 0.5 wt% increased by 41%, reaching 94.6 MPa. Benefiting from the absorption of UV light by GO and reflection by SiO2, in the UV-A region, when the DDM−GO@SiO2 content is only 2 wt%, the transmission rate is significantly reduced, and its shielding efficiency can reach 95.21% from 79.25% of pure TPU. In addition, the DDM−GO@SiO2/TPU composites have the advantages of a simple preparation process and low cost. This type of material holds great promise for functional coatings and high-performance thin film materials.In this work, DDM was used to hydrophobically modify GO to improve dispersion in TPU. DDM−GO@SiO


The curing processes of the composites were assessed via Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The effects on dielectric properties and heat resistance of those composites with different proportion of BCB-POSS and DVS-BCB were investigated using an impedance analyzer and thermogravimetric analyzer (TGA), respectively. The thermal curing of composites could be carried out by ring-opening polymerization (ROP) of the BCB four-member rings of BCB-POSS or DVS-BCB and those of P(4-MB-co-1-MP). With increasing the proportion of BCB-POSS to 30%, the 5% weight loss temperature (T5%) of P(4-MB-co-1-MP)/BCB-POSS composites was raised visibly, whereas the dielectric constant (k) was decreased owing to the introduction of nanopores into POSS. For P(4-MB-co-1-MP)/DVS-BCB composites, the T5% and k were slightly raised with increasing the proportion of DVS-BCB. The above results indicated that the BCB-POSS showed advantages over conventional fillers to simultaneously improve thermostability and decrease k.Benzocyclobutene-modified silsesquioxane (BCB-POSS) and divinyl tetramethyl disiloxane-bisbenzocyclobutene (DVS-BCB) prepolymer were introduced into the containing benzocyclobutene (BCB) unit matrix resin P(4-MB-co-1-MP) polymerized from 1-methyl-1-(4-benzocyclobutenyl) silacyclobutane (4-MSCBBCB) and 1-methyl-1-phenylsilacyclobutane (1-MPSCB), respectively. The low dielectric constant (low- Pexplored ,7,8,9,10operties ,16,17,18operties ,20,21.k, small dielectric loss, low water absorption and low curing temperature. Meanwhile, DVS-BCB resin has been widely used in microelectronic fields including IC stress buffering/passivation layer, multi-layer wiring, high-frequency devices, and so on [With the continuous development of science and technology, the comprehensive performance of dielectric materials  are required to be more and more excellent. The methods of improving the comprehensive performance of dielectric materials are widely investigated and have been expanded from the traditional molecular structure design to compounds, doping and hybridization . POSS isnd so on ,30,31.k of the composite materials. With the addition of DVS-BCB prepolymer, the k of the composites was slightly increased, and the thermal stability was improved distinctly. Those siloxane/carbosilane hybrid benzocyclobutene resin composites could be potentially used in microelectronics and other fields.In this present report, the ROP of 4-MSCBBCB and 1-MPSCB was carried out. Two hybridized resins, P(4-MB-co-1-MP)/BCB-POSS and P(4-MB-co-1-MP)/DVS-BCB, were prepared by the physical blending of copolymer P(4-MB-co-1-MP) with BCB-POSS and DVS-BCB prepolymers, respectively. It is presented that the introduction of BCB-POSS can improve the thermal stability of the cured resins comparing with the matrix materials, which can effectively reduce the 2PtCl6·6H2O, 95%), tetrahydrofuran , and allyl chloride (97%) were purchased from J&K Scientific Ltd. . Karstedt’s catalyst was purchased from Sam Chemical Technology Co., Ltd. . Magnesium (CP), sodium sulfate anhydrous (CP), 1,2-dibromoethane (CP), petroleum ether (AR), methanol (AR), bromobenzene (AR), toluene (AR), iodine (AR), and other solvents were purchased from Chengdu Kelong Chemical Reagent Co., Ltd. . Tetrahydrofuran was dried through JC Meyer solvent drying system ; toluene was distilled over sodium-benzophenone before use; other solvents were used without further purification. All manipulation involving air-sensitive materials was carried out in oven-dried glassware under nitrogen.4-Bromobenzocyclobutene (97%) and DVS-BCB were purchased from Beichuan Ruihui Technology Co., Ltd. . BCB-POSS was prepared by our research group; the method can be found in the 1H and 13C NMR spectra were obtained with a Bruker Avance-600 spectrometer  using deuterated chloroform (CDCl3) as the solvent and tetramethylsilane (TMS) as the internal reference. Fourier-transform infrared (FTIR) spectroscopy measurements at 400–4000 cm−1 were conducted on a Nicolet iS50 FTIR spectrometer  at room temperature, and the sample films were prepared by casting solutions on potassium bromide (KBr) plates. Both sides of composite resin samples were coated with silver paint to form electrodes, and the capacitance was measured by using a 4294A precision impedance analyzer  at various frequencies ranging from 40 Hz to 40 MHz at ambient temperature. The dielectric constant (εr) was calculated by the following formula C, d, and S represent capacitance, thickness, and electrode area, respectively. ε0 represents the permittivity of free space, which is 8.854 × 10−12 F/m. Thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) were performed on a synchronous thermal analyzer  in nitrogen atmosphere at a heating rate of 10 °C/min.At room temperature, liquid-state All reactions were carried out in a purified nitrogen atmosphere using the standard Schlenk technique. An amount of 15 mL of toluene was injected into a round bottom flask, and a mixture of methyl dichlorosilane , allyl chloride , and chloroplatinic acid  was slowly added. The mixture was stirred at 60 °C for 3 h. The excess solvents and raw materials were removed by atmospheric distillation and vacuum distillation successively to obtain 3-chloropropyl-methyl dichlorosilane.−1): 3055, 2963, 2929, 2858, 1590, 1466, 1395, 1256, 1192, 1119, 860, 720. 1H NMR  δ(ppm): 7.50–7.51 , 7.36 , 7.12–7.14 , 3.22–3.25 , 2.17–2.22 , 1.15–1.33 , 0.56 . 13C NMR  δ(ppm): 147.62, 145.75, 136.79, 131.78, 127.20, 122.06, 29.93, 29.85, 18.13, 14.55, −1.56.In a nitrogen atmosphere, magnesium ribbons  were put in a three-necked round bottom flask, then THF (5 mL) was added to moisten the magnesium ribbons, and 1,2-dibromoethane  was added to activate Mg. The mixture of 3-chloropropyl-methyl dichlorosilane  and THF (10 mL) was added into the reaction system drop by drop, and the reaction mixture was heated to 55 °C and continually stirred for 3 h. After the reaction system cooled down to room temperature, under the protection of nitrogen and with stirring, the mixture of 4-bromobenzocyclobutene  and THF (18 mL) was added into the reaction system drop by drop. Then the reaction mixture was continually stirred and kept in a reflux state for 2 h. After the reaction was quenched using NaCl solution, the organic layer was extracted by hexane and washed using water, then dried with sodium sulfate anhydrous overnight. The 4-MSCBBCB  was obtained by column chromatography with petroleum ether as eluent, and the yield was 74%. FTIR : 3068, 2963, 2926, 1588, 1396, 1250, 1116, 867, 772, 732, 698. 1H NMR  δ(ppm): 7.41–7.66 , 2.18–2.24 , 1.16–1.33 , 0.57 . 13C NMR  δ(ppm): 138.68, 133.48, 129.40, 127.91, 18.23, 14.34, −1.79.Replacing 4-bromobenzocyclobutene with bromobenzene, the preparation of 1-MPSCB is similar to the preparation method of 4-MSCBBCB. The yield of it was 76%. FTIR : 3066, 2957, 2920, 2873, 1588, 1457, 1253, 732. 1H NMR  δ(ppm): 7.00–7.38 (ArH), 3.17 (‒CH2CH2‒), 1.31 (Si‒C‒CH2‒), 0.74 (Si‒CH2‒C), 0.14 (‒CH3). 13C NMR  δ(ppm): 146.61, 145.33, 138.81, 136.80, 133.76, 132.04, 128.60, 127.60, 127.51, 121.76, 29.91, 29.75, 19.16, 18.87, 18.36, −4.73, −5.00.The polymerization reaction was carried out in a purified nitrogen atmosphere using the standard Schlenk technique. At room temperature, 4-MSCBBCB , 1-MPSCb , and toluene (2 mL) were injected into the anaerobic tube. The anaerobic tube was put into liquid nitrogen to freeze and vacuum for several minutes, then the anaerobic tube was moved out to unfreeze at room temperature under nitrogen conditions. This operation was repeated three times to ensure that the oxygen in the reaction system was removed completely. Then, Karstedt catalyst  was injected into the reaction system, and the reaction mixture was heated to 70 °C and reacted continuously for 15 h. The colorless viscous liquid was obtained after column chromatography with toluene as eluent, filtration and concentration. P(4-MB-co-1-MP) was recrystallized in methanol 3 times and then dried in a 50 °C vacuum drying oven for 24 h, with a yield of 80%. FTIR  at 0 wt.%, 15 wt.% and 30 wt.%, respectively. Then, the mixture was dissolved with toluene and transferred to Durham’s fermentation tube. After solvent volatilization was completed, the Durham’s fermentation tube containing the reaction mixture was placed in a vacuum drying oven and the temperature was elevated and kept at 150 °C for 3 h. After complete degassing, the temperature was kept at 180 °C for 2 h, 200 °C for 2 h, 220 °C for 2 h and 250 °C for 1 h, successively. After curing and cooling to room temperature, the P(4-MB-co-1-MP)/BCB-POSS composite resin sample was obtained.In a nitrogen atmosphere, DVS-BCB was heated slowly from room temperature to 175 °C and kept at 175 °C for 3.5 h to obtain DVS-BCB prepolymer. The preparation method of the P(4-MB-co-1-MP)/DVS-BCB composite resin-cured sample from P(4-MB-co-1-MP) and prepolymerized DVS-BCB is similar to that of P(4-MB-co-1-MP)/BCB-POSS.In this present work, 4-MSCBBCB, 1-MPSCB, and P(4-MB-co-1-MP) copolymer were prepared and characterized. The schematic diagram of synthesis of P(4-MB-co-MP) is shown in 1H NMR, and 13C NMR spectra of 4-MSCBBCB, 1-MPSCB, and P(4-MB-co-MP) are shown in The FTIR, −1 belongs to the stretching vibration of C‒H bonds of benzene ring, and the stretching vibration peaks of C‒H bonds of methyl and methylene appeared at 2963, 2929, and 2858 cm−1, respectively. Moreover, the stretching vibration peaks of C=C bonds of benzene ring appeared at 1590 cm−1, the oscillating vibration absorption peaks of the four-member ring of BCB appeared at 1466 cm−1, the symmetry deformation vibration peaks at 1395 cm−1 and 1256 cm−1 belonged to Si‒CH3 bonds, the stretching vibration peaks at 1192 cm−1 belonged to C‒H bonds of the four-member ring of BCB, the characteristic absorption peaks of silicon heterocyclic butane appeared at 860 cm−1 and 1119 cm−1, and the planar oscillating vibration absorption peaks of ‒CH2‒‒CH2‒‒CH2‒ appeared at 720 cm−1.As the FTIR spectra of 4-MSCBBCB  show, th1H NMR spectra of 4-MSCBBCB, the hydrogen signals at 1.55–2.22 ppm would be assigned to the silicon heterocyclic butane, the hydrogen signals at 3.22–3.25 ppm would be assigned to the four-member ring of BCB, the hydrogen signals at 7.12–7.51 ppm would be assigned to the benzene ring of BCB, and the hydrogen signals at 0.56 ppm would be assigned to the methyl directly attached to the silicon atom.As indicated in 13C NMR spectra of 4-MSCBBCB) shows, the characteristic signals of the carbon atoms of benzene ring were found to appear at 147.62–122.06 ppm, the characteristic signals of the carbon atoms of the four-member ring of BCB were found to appear at 29.93 ppm and 29.85 ppm, the carbon signals at 18.13 ppm and 14.55 ppm would be assigned to the methylene of silicon heterocyclic butane. Because of the symmetrical structure, only two sets of signals peaks appeared. Moreover, the carbon signals at –1.56 ppm would be assigned to the carbon atoms on methyl that were directly attached to silicon atom.As −1 belongs to the stretching vibration of C‒H bonds of the phenyl, and the stretching vibration peaks of C‒H bonds of methyl and methylene appeared at 2963 cm−1 and 2926 cm−1, respectively. Moreover, the stretching vibration peaks of C=C bonds of the phenyl appeared at 1588 cm−1, the symmetry deformation vibration peaks at 1396 cm−1 and 1250 cm−1 belonged to Si‒CH3 bonds, the characteristic absorption peaks of silicon heterocyclic butane appeared at 867 cm−1 and 1116 cm−1, the plane bending vibration peaks at 772 cm−1 and 698 cm−1 belonged to C‒H bonds of phenyl, and the planar oscillating vibration absorption peaks of ‒CH2‒CH2‒CH2‒ appeared at 732 cm−1.As the FTIR spectra of 1-MPSCB  show, th1H NMR spectra of 1-MPSCB), the hydrogen signals at 1.16–2.24 ppm would be assigned to the silacyclobutane, the hydrogen signals at 7.41–7.66 ppm would be assigned to the phenyl, and the hydrogen signals at 0.57 ppm would be assigned to the methyl that were directly attached to the silicon atom.As indicated in 13C NMR spectra of 1-MPSCB) shows, the carbon signals of the phenyl were found to appear at 138.68–127.91 ppm. The characteristic signals of the carbon atoms of silacyclobutane were found to appear at 18.23 ppm and 14.34 ppm, and because of the symmetrical structure, there were only two sets of signal peaks. Moreover, the carbon signals at –1.79 ppm would be assigned to the methyl that were directly attached to the silicon atom.As −1 belonged to the stretching vibration of C‒H bonds of benzene rings, and the stretching vibration peaks of C‒H bonds of methyl and methylene appeared at 2957, 2920, and 2873 cm−1, respectively. The stretching vibration peak of C=C bonds of benzene rings appeared at 1588 cm−1. Moreover, the absorption peak of the four-member ring of BCB appeared at 1457 cm−1, the symmetry deformation vibration peak at 1253 cm−1 belonged to the Si‒CH3 bonds, and the planar oscillating vibration absorption peaks of ‒CH2‒CH2‒CH2‒ appeared at 732 cm−1. According to the FTIR spectra of P(4-MB-co-1-MP), it was present that the BCB units were successfully introduced into the linear polycarbosilane.As 1H NMR spectra of P(4-MB-co-1-MP). Comparing 1H NMR spectra of 4-MSCBBCB monomer) and 1H NMR spectra of 1-MPSCB monomer), the hydrogen signals at 1.15–2.22 ppm and 1.16–2.24 ppm disappeared, which would be assigned to the methylenes of silacyclobutane of 4–MSCBBCB and 1-MPSCB, respectively, whereas the new hydrogen signal peaks of 1.31 ppm (Si‒C‒CH2) and 0.74 ppm (Si‒CH2‒C) in the 1H NMR spectra of P(4-MB-co-1-MP) corresponded to the hydrogen of methylene after ring opening. Both sets of signal peaks of the methylene of silacyclobutane of 4-MSCBBCB and 1-MPSCB moved towards the lower chemical shift, indicating that the ROP reactions happened, and the linear polymer was prepared successfully.13C NMR spectra of P(4-MB-co-1-MP) are shown in 3 were at 77.22, 77.01 and 76.79 ppm. The carbon signal peaks of methylene in BCB appeared at 29.91 ppm and 29.75 ppm, and because of the symmetrical structure, there were only two sets of signal peaks. Moreover, the carbon signal peaks which appeared at 19.16–18.36 ppm corresponded to methylene of the backbone chains of P(4-MB-co-1-MP), and the signal peaks at −4.73 ppm and −5.00 ppm are attributed to the methyl carbon atoms that were directly attached to silicon atoms.The o-quinodimethanes derived from BCB. However, there were no exothermic peaks in the cured resin DSC curves, indicating that the linear polycarbosilane had been completely cured under the curing conditions shown in the experimental part. Therefore, we suggested that the curing of polycarbosilane was attributed to the ring-opening of the four-member rings of BCB on the side chain to form a highly reactive o-dimethylquinone intermediate, which eventually formed cyclooctadiene. It could also be concluded that the thermal cross-linking groups of BCB had been successfully introduced into the P(4-MB-co-1-MP) linear polymers.DSC and FTIR spectroscopy were used to investigate the curing behaviors of P(4-MB-co-1-MP) and its siloxane/carbosilane hybrid benzocyclobutene resin composites. The DSC curves of P(4-MB-co-1-MP), P(4-MB-co-1-MP)/BCB-POSS, and P(4-MB-co-1-MP)/DVS-BCB (before and after curing) are shown in −1, which could be carried out by the four-member ring of BCB. After curing, a new symmetric stretching vibration peak occurred at 1488 cm−1, which belonged to the C‒H bonds of methylene obtained from the ring-opening of the four-member ring of BCB.Moreover, as shown in −1 in the P(4-MB-co-1-MP)/BCB-POSS before curing, which belonged to the four-member ring of BCB. After curing, the new C‒H bond symmetric stretching vibration absorption peak of ‒CH2‒ due to the ring-opening reaction of BCB appeared at 1489 cm−1. The curing mechanism could also be inferred from the FTIR spectra of P(4-MB-co-1-MP)/BCB-POSS before and after curing. o-dimethylquinone firstly at high temperature, and then the cyclooctadiene was obtained through the Diels–Alder reaction.According to −1 on the FTIR spectra of P(4-MB-co-1-MP)/DVS-BCB before curing, which was due to the four-member rings of BCB. After curing, a new C‒H bond symmetric stretching vibration absorption peak of ‒CH2‒, which belonged to the ring-opening reaction of the four-member ring of BCB, appeared at 1490 cm−1. As shown in As shown in T5%) of P(4-MB-co-1-MP)/BCB-POSS composites was raised to 464.5 °C, when the proportion of BCB-POSS increased to 30%. It was suggested that the cross-linking sites increased with the introduction of BCB of BCB-POSS. In addition, owing to the nanoscale effect, more polymer chains of P(4-MB-co-1-MP) could be located around POSS. As a result, the chain mobility will be decreased. This effect will also contribute to the improvement of thermostability to a certain degree. Therefore, by increasing the proportion of BCB-POSS added, the ratio of carbon residue of P(4-MB-co-1-MP)/BCB-POSS composites increased, and the heat resistance was also improved.TGA was used to evaluate the thermal stability of P(4-MB-co-1-MP), P(4-MB-co-1-MP)/BCB-POSS, and P(4-MB-co-1-MP)/DVS-BCB composites with different proportions of BCB-POSS or DVS-BCB. As shown in T5% of P(4-MB-co-1-MP)/DVS-BCB composites also increased with increasing the proportion of DVS-BCB added, and when the proportion of DVS-BCB increased to 30%, T5% reached 464.6 °C. It was speculated that the thermal reaction cross-linking sites increased with increasing the proportion of DVS-BCB added, and more stable six-membered ring structures were formed through the addition reaction. Moreover, DVS-BCB contains a certain number of Si‒O bonds with higher bond energy, so the thermal stability of P(4-MB-co-1-MP)/DVS-BCB was better than that of P(4-MB-co-1-MP).k materials mainly include inter-layered/lined media and circuit boards. For the former application, the low-k materials were required to withstand the thermal anneal from 450 °C under an inert atmosphere. Thus, the T5% should be higher than 450 °C. For the latter application, the low-k materials were required to be stable at temperatures below 200 °C. Thus, one can conclude that the thermostability of P(4-MB-co-1-MP)/BCB-POSS and P(4-MB-co-1-MP)/DVS-BCB composites satisfies the requirement of microelectronic applications.The microelectronics applications of low-k values of P(4-MB-co-1-MP), P(4-MB-co-1-MP)/BCB-POSS and P(4-MB-co-1-MP)/DVS-BCB cured resins were determined with the frequency range of 40 Hz to 40 MHz. As k of those cured resins showed a regular trend. According to k of P(4-MB-co-1-MP)/BCB-POSS with different proportions of BCB-POSS were clearly lower than that of P(4-MB-co-1-MP), and the k of cured resins decreased with increasing proportions of BCB-POSS added: the k of P(4-MB-co-1-MP), P(4-MB-co-1-MP)/BCB-POSS (15 wt.%) and P(4-MB-co-1-MP)/BCB-POSS (30 wt.%) at 10 MHz were 2.52, 2.45 and 2.36, respectively. The k of cured P(4-MB-co-1-MP) was 2.52, and there was an obvious decreasing trend after adding BCB-POSS. For example, the dielectric constant (k) of P(4-MB-co-1-MP)/BCB-POSS (30 wt.%) decreased from 2.52 to 2.36 (10 MHz) when the proportion of BCB-POSS was 30%. It was indicated that the reasons for the decreases in k were mainly due to the special structure similar to holes of POSS, and at the same time, more cross-linking sites brought by BCB-POSS increased the cross-linking density of the composites. Moreover, POSS has a hexahedral hollow structure composed of Si‒O‒Si bonds, and the k of air is 1; therefore, the k of composites eventually decreased.The dielectric properties were investigated by means of the impedance method at room temperature. The k of the composites increased slightly from 2.52 to 2.65 (10 MHz) with increasing the proportions of DVS-BCB added. It was suggested that although DVS-BCB has two kinds of cross-linking sites, the proportion of Si‒O‒Si bonds in the structure was larger, and the polarizability was higher than those of C‒C bonds and Si‒C bonds, which was an important reason for the increase in k.As k than those of DVS-BCB. The above results indicated that the BCB-POSS showed advantages over conventional fillers to simultaneously improve thermostability and decrease k.The results show that there are more advantages of BCB-POSS on enhancing the thermostability and reducing k decreased from 2.52 to 2.36 at 10 MHz. At the same time, when the proportion of BCB-POSS reached a certain amount, T5% of the composite resins was higher than that of the original matrix resin and the carbon residual ratio was higher, indicating that the thermal stability of the composite resin was improved by hybridizing with inorganic medium. As compared with BCB-POSS, the introduction of DVS-BCB resulted in an increase in the k and slight improvement of thermostability. Overall, our work showed that the introduction of POSS-based fillers in P(4-MB-co-1-MP) enabled the decrease in dielectric constant and the enhancement of thermostability owing to its porous and nanoscale effect, and introducing BCB-POSS has more advantages than introducing DVS-BCB.In this work, 4-MSCBBCB and 1-MPSCB were prepared through Grignard reactions, and linear copolymers P(4-MB-co-1-MP) were prepared by Pt-catalyzed ring-opening polymerization. BCB-POSS was prepared by silicon hydrogen addition reaction, and DVS-BCB prepolymer was obtained by prepolymerization. The thermal properties and dielectric properties of cured P(4-MB-co-1-MP)/BCB-POSS and P(4-MB-co-1-MP)/DVS-BCB siloxane/carbosilane hybrid benzocyclobutene resin composites were investigated. The dielectric properties of P(4-MB-co-1-MP)/BCB-POSS composites were improved compared with those of the original matrix resin by adjusting the proportion of BCB-POSS added. The


The COVID-19 pandemic led to rapid changes in demand and delivery of primary care services that could have led to increases in antibiotic prescribing.We investigated the impact of the COVID-19 pandemic on oral antibiotic dispensing rates in primary care in Wales using longitudinal analysis of monthly oral antibiotic dispensing data from 1 April 2018 to 30 April 2021.We used All-Wales primary care dispensing data. We examined trends in oral antibiotic dispensing per 1,000 people for Wales and for individual Health Boards. We used interrupted time series analysis to estimate changes in trends pre- and post-April 2020 to assess the impact of the first and subsequent lockdowns.Between April 2020 and April 2021, antibiotic dispensing in Wales was lower compared with the same period in 2018 and 2019, with an average monthly decrease of 14.00 dispensed items per 1,000 registered patients . The overall prepandemic monthly antibiotic dispensing rate ranged from 48.5 to 67.4 antibiotic items per 1,000 registered patients. From the onset of the pandemic, it ranged from 40.3 to 49.07 antibiotic items per 1,000 registered patients. This reduction was primarily driven by narrow-spectrum antibiotics. Statistically significant reductions were also observed for antibiotics commonly dispensed for the treatment of respiratory tract infections. Dispensing of antibiotics primarily used for urinary and skin infections remained stable.Despite complexities of consulting during the COVID-19 pandemic in primary care we found no evidence of an increase in antibiotic dispensing during this time. Antibiotic dispensing from onset of the COVID-19 pandemic has decreased.This decrease was driven mainly by narrow-spectrum antibiotics.Dispensing rates of broad-spectrum antibiotics remained stable.Dispensing of antibiotics primarily used for urinary and skin infections remained stable.1 An estimated 9%–23% of antibiotics prescribed in English Primary Care between 2013 and 2015 were potentially clinically unnecessary.2 Widespread prescribing of antibiotics is thought to increase antimicrobial resistance (AMR), which poses a serious challenge to patient safety and provision of health services in the years to come.3 Substantial progress has been made in recent years to reduce rates of antibiotic prescribing in response to concerns over rising rates of AMR. The observed reduction in the total number of antibiotic items dispensed in England from 2015 to 2019 was 14%,1 and in Wales from 2013 to 2018 was 11.9%.4Most antibiotic prescribing occurs in the community. In 2019, 71% of antibiotics dispensed in the NHS in England were prescribed by Primary Care.5 In England, the number of telephone appointments in general practice increased by 270% between April and August 2020 in comparison to the corresponding period in 2019.6 Considerable numbers of people with respiratory tract symptoms were triaged remotely, there was uncertainty around COVID-19 illness, and some antibiotics (e.g. Azithromycin) were promoted as potentially beneficial.7 These issues overlap with key factors known to influence prescribing such as clinical uncertainty and workload time pressures.8 Furthermore, previous studies found that antibiotics are frequently overprescribed for respiratory tract infections (RTIs),9 and influenza like illness accounts for substantial inappropriate antibiotic use.10 Therefore, many clinicians were concerned that antibiotic dispensing would rise during the pandemic due to remote consulting, increased clinical uncertainty, and higher prevalence of respiratory symptoms in the community.The COVID-19 pandemic led to accelerated adoption of remote consulting in UK primary care.11Despite initial concerns, recent studies of antibiotic prescribing trends primarily observed reductions in use. In the Netherlands prescribing of antibiotics decreased during the COVID-19 pandemic from 600 per 100,000 patients to 360 per 100,000 patients, especially for RTIs.12 In Scotland, an initial 44% increase in the number of prescriptions for commonly used antibiotics for RTIs was observed in the week ending 22 March 2020, compared with the corresponding week in 2019.13 However, by the end of May 2020, 34% fewer prescriptions were issued compared with the corresponding week in 2019.13 In North-West London, from March to November 2020, a decrease of 3,504 antibiotic items per month was observed (compared with decrease of only 584 items per month prior to the onset of pandemic).14In the United Kingdom as a whole, antibiotic prescribing fell below predicted rates as compared with the previous year between April and August (antibiotic prescribing adjusted rate ratio [ARR] ranging from 0.73 to 0.91), but higher rates were observed in March 2020 (ARR = 1.13) compared with other months between February and September 2020.15 A large meta-analysis of 154 empirical studies concluded that 3 quarters of patients with COVID-19 received antibiotics, while bacterial coinfection was estimated to be present in only 8.6% of cases.16In contrast, the United States observed that 72% of COVID-19 patients received antibiotics, even when there was no evidence of secondary bacterial infection.17 As per the Welsh Government Antibacterial Stewardship Plan 2019, prepandemic there has been a decrease in the total antibiotic use among almost all Health Boards in Wales with a significant reduction in prescriptions of agents used for the treatment of respiratory infections such as amoxicillin and macrolides.4 Therefore, due to higher rates of antibiotic prescribing compared with the rest of the United Kingdom, previously published data from the United Kingdom as a whole,12 Scotland,13 or London14 might not be representative of rates of antibiotic dispensing in Wales during the pandemic.Wales traditionally has high rates of antibiotic prescriptions.18 and thus dispensing rates are likely more reflective of actual usage than prescribing rates. While generally reflecting prescribing practices, dispensing rates provide better insight into antibiotic usage in the population. Therefore, in this research we evaluated whether antibiotic usage had changed in Wales during the COVID-19 pandemic using All-Wales dispensing data. We hypothesized that increased rates of remote consulting and respiratory symptoms may have led to an increase in antibiotic dispensing following the onset of the COVID-19 pandemic.Most previous research reporting antibiotic usage during the COVID-19 pandemic used prescribing rates. However, between 11% and 19% of prescriptions are not dispensed,This was a longitudinal analysis of oral antibiotic dispensing data in Wales from 1 April 2018 to 30 April 2021.In Wales, General Practitioners (GPs) provide free of charge universal healthcare. GPs work within specific geographical areas called Health Boards, and each Health Board provides antibiotic guidance based on local patterns of AMR which assists clinicians when making decisions about antibiotic prescribing.General Practice Prescribing Data (CASPA) is maintained by the NHS Wales Shared Services Partnership. It includes information on all antibiotics prescribed in Wales by GPs and nonmedical prescribers in each practice. This information is available as practice-level aggregated data and no clinical or demographic data are available about individual patients, or details of consultation or diagnosis. For the prescription to be included in the dataset, it must be dispensed in the community within Wales or England . Prescription data included antibiotic details such as antibiotic name, route of administration, British National Formulary code, and month it was dispensed, as well as details of individual unique GP practice code, and their associated Health Board.Dispensing was used rather than prescribing in this study. Dispensing is not the same as prescribing as some patients may not take their prescriptions to a pharmacy for dispensing. However, dispensing can be argued to be a better marker of clinical necessity as in some circumstances delayed prescriptions might be used, or patients may choose not to collect their antibiotics, with dispensing data reflecting actual use better than prescribing data.We extracted numbers of antibiotic items dispensed in general practices in Wales per month between April 2018 and April 2021. The first day of lockdown in Wales was the 23rd of March 2020. Dispensing data were available on a monthly, not daily basis and therefore, for the purpose of the interrupted time series (ITS) analysis, April 2020 was treated as the start of lockdown.19 Broad-spectrum antibiotics included co-amoxiclav, cephalosporines, and quinolones. All other antibiotics have been classified as narrow spectrum for the purpose of this analysis.Antibiotic items were combined to allow for antibiotic dispensing trends to be examined at the All Wales and Health Board levels. We initially examined the number of items dispensed per month for all antibiotics in Wales, and then for commonly prescribed antibiotics for RTIs and ear, nose, throat (ENT) conditions  and commonly prescribed antibiotics for urinary tract infections ; as well as flucloxacillin, often used for treatment of skin infections  . These a20 Dispensing rates were expressed as number of antibiotic items dispensed per 1,000 registered patients.The numerator used to calculate antibiotic dispensing rates was the number of antibiotic items dispensed. The denominator was an estimate of the population of Wales overall and in each Health Board area. Denominator estimates were calculated based on numbers of patients registered at each General Practice each month. There were small fluctuations in monthly counts due to patients changing practices or due to temporary patient registrations (such as students). The All-Wales monthly denominator counts in our analysis ranged from 3,176,644 to 3,242,279 per month, similar to the mid-2019 Welsh population count of 3,152,879.P values. Analyses were performed using the itsa command in Stata V.16.21Monthly dispensing rates and 95% confidence intervals (CIs) were calculated at all Wales and Health Board level. Dispensing rates over time were displayed graphically to compare the prepandemic period (April 2018–March 2020) to the pandemic period (April 2020–April 2021). Dispensing trends were analysed for all Wales, by individual Health Boards and by commonly used antibiotics. An ITS approach compared dispensing trend prepandemic to the pandemic. This analysis was performed using ordinary-least squares regression with Newey–West standard errors and a lag for the autocorrelation structure. The Cumby–Huizinga test for autocorrelation was examined to determine the appropriate autocorrelation structure to be accounted for in the model. The model included prepandemic and during pandemic trends, as well as a coefficient to examine a step change in level immediately postpandemic (March–April 2020). The parameter estimates are presented alongside 95% CIs and We identified 6,270,703 antibiotic items dispensed between April 2018 and April 2021. Monthly estimates for the whole Welsh population ranged from 39.3 antibiotic items per 1,000 registered patients (in February 2021) to 67.4 antibiotic items per 1,000 registered patients (in December 2019). The overall antibiotic dispensing rate was 54.9 antibiotic items per 1,000 patients at the start of study period (April 2018) and 42.4 antibiotic items per 1,000 patients at the end (April 2021) . The oveThe ITS analysis found a statistically significant decrease in dispensing rates  from April 2020 to April 2021 in comparison to predictions based on dispensed number of antibiotics between April 2018 and March 2020 .This reduction in overall antibiotic dispensing was primarily driven by fewer narrow-spectrum antibiotics . AverageIn March 2020 there was a peak in antibiotic dispensing in Wales of 59.5 items per 1,000 patients compared with 56.6 in March 2019 . This inAmongst the reduced number of dispensed antibiotics, the number of items of antibiotics commonly used for treatment of respiratory and ENT conditions changed markedly . The datThis study assessed the impact of the COVID-19 pandemic on the number of oral antibiotic items dispensed in Wales. Following an initial increase in March 2020, we observed a marked reduction in the number of items dispensed, especially in those used for the treatment of RTIs. For amoxicillin and doxycycline, the number of antibiotic prescriptions dispensed in general practice between April and July 2020 was 140,799 (33.5%) lower than the figure for the corresponding period in 2019 . Rates of broad-spectrum antibiotic dispensing remained steady during the pandemic.There was a reduction in antibiotic dispensing from April 2020 to May 2020 (in May 2020 easing of restrictions started in England). Between May and August 2020 much lower antibiotic dispensing rates were observed in comparison to 2019. From August to September 2020, there was a subsequent recovery in rates of antibiotic dispensing. This might reflect easing of COVID-19 restrictions in Wales from mid-July to September 2020. In October and November 2020, further restrictions were reintroduced, which corresponded again to lower rates of antibiotic dispensing. From December 2020 to March 2021, much lower antibiotic dispensing rates were observed in comparison to 2019. This may have been due to the introduction of another national lockdown in the United Kingdom between December 2020 and March 2021.22 Our overall dispensing rates are lower than reported by Public Health Wales for previous years.4 This may be because we only included oral preparations whereas Public Health Wales analyses included topical, parental, inhaled, rectal, and genital, as well as oral preparations.4The overall number of antibiotic items dispensed in 2019 of 673 items per 1,000 patients was similar to recent estimates from England .17 with an 11.9% reduction over the 5-year period from 2013 to 2018.4 This reduction is similar to the reported 12.2% decrease in total antibiotic consumption in England between 2015 and 2019.1 Data from The Netherlands also showed a decline in the number of antibiotics prescribed since the onset of pandemic, particularly for RTIs.11 However, data from the United States reported increased usage of antibiotics during the pandemic.15 Data from North-West London suggested a decrease in the number of antibiotics prescribed from March to November 2020, in comparison to the same period in 2019.14 In England, the number of antibiotic prescriptions made in general practice between April and August 2020 was 15.48% lower than in the corresponding period in 2019, but the number of antibiotic prescriptions was 6.71% higher than expected when accounting for the decrease in the absolute number of GP appointments during this period.6 In Scotland, an initial increase was observed from the third week of March in the number of prescriptions issued for the treatment of RTIs, followed by a decrease below prepandemic levels towards the end of May 2020.13 A population-based primary care cohort study across all nations of the United Kingdom has described similar findings with antibiotic prescribing declining below predicted rates between April and August 2020.12Prescribing and dispensing have decreased in recent years with the aim of reducing unnecessary antibiotic prescribing in the United Kingdom. The most recent data from Wales show a 7% reduction in dispensed total antimicrobial volume in the 2018/2019 financial year compared with 2017/2018,12 Scotland,13 and North-West London,14 as it uses dispensing rates of antibiotics rather than prescribing rates. There are pros and cons to using both prescribing rates and dispensing rates of antibiotics. It could be argued that prescription rates might more accurately reflect how clinical practice has adapted to the pandemic, as they represent the clinical decision making process, which excludes patient behaviour such as medication adherence. However, clinical decision cannot always be easily measured as clinicians sometimes use delayed prescriptions which are prescribed but not necessarily intended to be used. Between 11% and 19% of prescriptions for any type of medications are not dispensed to patients. Antibiotics are the most commonly prescribed category of nondispensed drug.23 In antibiotic stewardship terms, antibiotic dispensing is more important than antibiotic prescribing. Data from Canada comparing antibiotic prescribing and dispensing suggested that primary care electronic medical records should not be used to monitor population level antibiotic use over time. These records are more appropriate to study differences in antibiotic prescribing at physician level than population-based trends.24 We therefore believe that dispensing rates provide better insight into antibiotic usage in the population than prescribing rates.This study is unique, unlike previously published research from the United Kingdom as a whole,Unfortunately, the data were only available as number of antibiotics issued by each GP practice in Wales, and we were not able to access details of individual consultations. Therefore, we were unable to obtain information about indication for antibiotic prescription, or patients sociodemographic characteristics. Only General Practice level data were available for this analysis. Dispensing data from other locations such as out-of-hours services, community resource teams, incontinence services, and community pharmacists not directly employed by General Practices are not included. No clinical information was available regarding the indication for antibiotics as we had no access to individual clinical records. We did not have access to the overall number of consultations in Wales during the period of the pandemic. Therefore, further studies looking at prescribing within consultation rates would provide useful insight into how antibiotic prescribing might have changed in General Practice due to different workloads.The COVID-19 pandemic appears to have had a substantial impact on dispensing of antibiotics at the population level in Wales, with significant reduction in antibiotics used for RTIs. This decline could be due to reduced primary care attendance or as social distancing measures were in place, due to lower rates of self-limiting viral RTIs in the community. Significant differences in dispensing rates were demonstrated between different Health Boards and recognizing this variability should help policymakers and practitioners to mitigate any inconsistency in antibiotic prescribing long term.Our findings suggest that antibiotic stewardship priorities have not been overlooked during the pandemic. The rates of dispensing of broad-spectrum antibiotics remained largely stable. Moreover, steady rates of dispensing for nonrespiratory conditions such as skin and urinary tract infections suggest that the public were still seeking medical advice for some common infections. Patients might have been more reluctant to consult GPs for common RTIs and/or there may have been lower rates of self-limiting viral illness and flu in the community, compared with previous years due to social distancing measurements. Further research is needed to evaluate the possible reasons for the reductions in antibiotic prescribing and dispensing during the Pandemic, such as looking more closely at the content of GP consultations and any changes to patients’ health-seeking behaviour.No founding was required for this study.No ethical approval was necessary as data are widely available in public domain.None declared.https://nwssp.nhs.wales/ourservices/primary-care-services/general-information/data-and-publications/general-practice-prescribing-data-extract/.The data used in this research are freely available at NHS Wales Shared Services Partnership: cmab141_suppl_Supplementary_MaterialClick here for additional data file.cmab141_suppl_Supplementary_ChecklistClick here for additional data file.


P = 0.033) related to deterioration in patients who underwent treatment. Serum IgG4 levels may be a useful predictor of unfavorable outcomes in untreated patients with IgG4-RD, who tend to have fewer affected organs and lower IgG4-RD responder index.The outcomes of patients with immunoglobulin G4 (IgG4)-related disease (IgG4-RD) who are not treated are unclear. This study aimed to clarify these outcomes and identify the factors related to them. We retrospectively evaluated various clinical features including laboratory data and involved organs at diagnosis in 107 patients with IgG4-RD, who were followed up for more than 6 months, at a single center in Japan. We compared the clinical features of the 27 untreated patients with those of the 80 patients treated with glucocorticoid. The patient outcomes were investigated, and logistic regression analysis was performed to identify factors related to them. The patients comprised 73 men and 34 women (median age 67 years). The untreated patients had significantly lower IgG4-RD responder index (9 vs. 12) and fewer affected organs (1 vs. 3) than did those treated with glucocorticoid. Of these 27 patients, 8 experienced deterioration of IgG4-RD after the diagnosis. In the age- and sex-adjusted logistic regression analysis, serum IgG4 elevation  was the only significant factor related to disease deterioration in untreated patients with IgG4-RD, whereas not serum IgG4 levels  but history of allergy (OR 3.134, 95% confidence interval 1.094–8.977,  In IgG4-RD, spontaneous, or at least temporary, remissions without treatment have been reported, and watchful waiting may be appropriate in certain patients with asymptomatic and inactive disease3.Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a systemic fibro-inflammatory disease that can affect almost all organs of the body5. The suggested predictors for SR included absence of serum IgG4 elevation, female gender, and stent placement for jaundice. On the other hand, unfavorable events including symptomatic, radiological, or functional exacerbation of the organ involved or relapse occurred in 50–70% of AIP patients without treatment6. New onset of diabetes mellitus and extensive multi-organ involvement were reported as predictors for unfavorable events in untreated patients5.Indeed, in type 1 autoimmune pancreatitis (AIP), it was reported that spontaneous remissions (SR) without treatment were observed in 55.7–65.0% of patientsHowever, the outcomes of patients with IgG4-RD, especially those except for AIP, who do not undergo treatment are still unclear. This state of affairs prompted us to undertake the present study to clarify the outcomes of untreated patients with IgG4-RD and the factors related to them.P = 0.048], fewer affected organs , and lower frequency of ophthalmic and renal parenchymal lesions .The profiles of the 107 IgG4-RD patients are listed in Table P = 0.020] and serum C3 levels  were significant factors negatively and positively related to SI, respectively, in untreated patients with IgG4-RD  months after the diagnosis (Table P = 0.030) was the only significant factor related to disease deterioration in untreated patients with IgG4-RD, whereas serum IgG4 levels did not relate to deterioration in patients who underwent treatment . On the other hand, history of allergy  was the only significant factor related to deterioration of disease in treated patients with IgG4-RD . We found that a serum IgG4 level of more than 983 mg/dL was the most appropriate cut-off that yielded a sensitivity of 75.0% and a specificity of 89.5% in predicting disease deterioration in untreated patients  curve. The area under the ROC curve was 0.780 ± 0.115  of the 27 patients and was significantly related not to serum IgG4 levels but to female gender and serum C3 levels. The fact that this significant relationship between SI and female gender in our study was consistent with finding in a previous one4 suggests that sexual differentiation is related to SI irrespective of which organ is involved. The significant relationship noted between SI and serum C3 levels, which were not evaluated in the previous studies5, indicates that SI is unlikely to occur in patients with hypocomplementemia as a possible indicator of disease activity. Accordingly, a watchful observation without treatment may be appropriate to a certain extent in IgG4-RD patients with these characteristics in addition to asymptomatic and inactive disease.Although spontaneous, or at least temporary, improvement without treatment has been reported in IgG4-RD, its prevalence and predictors remain to be clarified except for AIP. In AIP, it was reported that 55.7–65.0% of patients experienced SR and absence of serum IgG4 elevation, female gender, and stent placement for jaundice were significantly related to SR11. In addition, such persistent organ dysfunction was reported to be related to existing organ dysfunction at the time of treatment initiation10 or a long interval between diagnosis and treatment initiation11, suggesting that delay of treatment initiation should be avoided. This makes it important to recognize the factors associated with deterioration during observation without treatment in addition to the factors related to SI mentioned above.On the other hand, observation without treatment may impose some degree of risk of irreversible organ dysfunction in IgG4-RD. Recent studies investigating its long-term clinical course have disclosed that dysfunction of affected organs can persist despite glucocorticoid treatment in pancreatic, renal, and salivary gland lesions7 but inconsistent with those of the previous study investigating patients treated with rituximab12. Originally, an association between IgG4-RD and allergic diseases was suggested14. However, some more recent studies have indicated that allergic symptoms are not more frequent in IgG4-RD as compared to several control populations despite the common findings of serum IgE elevation and peripheral blood eosinophilia in the former17. Accordingly, any association of allergic predisposition with IgG4-RD pathogenesis or disease deterioration is yet unproven and remains to be clarified through further investigations.The present study showed that history of allergic disease, but not serum IgG4 elevation, was a factor significantly related to deterioration in treated IgG4-RD patients. This is consistent with the results of a recently published study by Liu et al.19 suggests that such untreated patients with higher serum IgG4 levels may have clinically silent affected organs and risk of future disease manifestations although whether an early treatment initiation for serum IgG4 elevation without obvious multiple organ manifestations is effective or not needs to be elucidated. More attention should be paid to deterioration of IgG4-RD in cases with high serum IgG4 levels disproportionate to the paucity of involved organs.On the other hand, interestingly, serum IgG4 elevation was the sole factor associated with deterioration in untreated patients in this study. A positive correlation between serum IgG4 levels and number of affected organsThis study had several limitations. First, the treatment regimen and follow-up protocols were inconsistent among patients because of its retrospective nature, complicating evaluation of the influence of detailed treatment protocol differences on patient outcome. Second, although this study included more patients with salivary and ophthalmic lesions than past ones, the number of patients was not sufficient to conclude the identified factors to be definitively significant predictors. Therefore, larger-scale prospective studies will be needed to confirm our results.In conclusion, the present study suggests that high serum IgG4 levels may be a useful predictor of the unfavorable outcomes of untreated patients with IgG4-RD, who tend to have fewer affected organs and lower IgG4-RD responder index. Although our results need to be confirmed through a larger-scale multicenter prospective study, the present observations may help to establish the optimal management strategy for IgG4-RD and in particular prevent treatment delay in untreated patients.20 or each set of organ-specific diagnostic criteria23 and exclusion of other diseases. Twenty-seven of these patients were followed up without treatment after the initial diagnosis. The following clinical factors at the time of diagnosis were retrospectively determined: age; gender; history of allergy; serum levels of IgG, IgG4, IgE, C3, C4, CH50, C-reactive protein (CRP), and creatinine; serum IgG4/IgE ratio24; peripheral blood eosinophil counts; presence of rheumatoid factor (RF) and anti-nuclear antibodies (ANA); number of affected organs; involvement of pancreas, salivary glands, ophthalmus, kidney, aorta/artery, retroperitoneum, and lung; IgG4-RD responder index. We compared the clinical features of these 27 patients with those of the 80 patients who underwent treatment. In addition, the patient outcomes were investigated, and logistic regression analysis was performed to assess factors related to the outcomes.We included 107 consecutive patients diagnosed with IgG4-RD between January 1, 2004, and December 31, 2017, who were followed-up for more than 6 months, at a single center in Japan. The diagnosis of IgG4-RD was made based on their fulfillment of the published comprehensive diagnostic criteria (CDC)History of allergy was defined as past diagnosis of allergic diseases or conditions such as allergic rhinitis, bronchial asthma, urticaria, atopic dermatitis, and drug allergy, but not merely positive results of skin prick test or specific IgE measurement without clinical manifestations.26. It is conceptualized based on the Birmingham Vasculitis Activity Score for Wegener’s Granulomatosis. Using this index, investigators assess disease activity organ by organ and calculate the total score by summing all of the scores based on the individual organ assessments. Disease activity determined by the investigator reflects a patient’s symptoms attributable to active IgG4-RD and significant findings from the physical examination, laboratory examinations, and imaging studies.The IgG4-RD responder index is a disease activity assessment tool used to measure response to therapy in a structured mannerDeterioration of IgG4-RD was defined as symptomatic, radiological, or functional exacerbation of the organ involved or de novo organ involvement. Spontaneous improvement (SI) of IgG4-RD was defined as symptomatic, radiological, or functional improvement of more than one of the organs involved and absence of deterioration as defined above in untreated patients.This study received institutional ethics board approval from the Medical Ethics Committee of Kanazawa University, and informed consent for the use of all data and samples was obtained from each patient. We conducted the research in compliance with the Declaration of Helsinki.P < 0.05.Statistical analysis was performed using SPSS V.25. Data are presented as median [interquartile range ] for continuous variables. The significance of differences between groups was determined using Mann–Whitney U test, while that of differences in frequencies was analyzed with Fisher’s exact probability test. For assessment of factors related to SI or deterioration of IgG4-RD during observation periods, unadjusted and age- and sex-adjusted logistic regression analyses were performed. Because SI or deterioration could frequently be detected only on imaging examinations, which were not always performed at frequent or regular intervals in this retrospective study, a time-to-event analysis such as Cox regression analysis was not used. In these logistic regression analyses, for continuous variables, unit for increments to calculate odds ratios were set at 1 year for age; 100 mg/dL for serum IgG4 and IgG levels; 100 IU/mL for serum IgE levels; 1 U/mL for serum CH50 levels; 1 mg/dL for serum C3, C4, CRP, and creatinine levels; 100 /µL for eosinophil counts. In addition, ROC curve analysis was performed to test the usefulness of certain parameters for the prediction of disease deterioration and to determine the appropriate cut-off value. Significant differences were defined as This study received institutional ethics board approval from the Medical Ethics Committee of Kanazawa University, and informed consent for the use of all data and samples was obtained from each patient. We conducted the research in compliance with the Declaration of Helsinki.Not applicable.