The innovation of the proposed study lies in employing both classical and iterative robust statistical methods. In comparison with classical statistical methods, robust methods ensure a smaller impact of outliers and other anomalies on the measurement results. Following the analyses, clear differences were found between the types of detected discrepancy of test results, which occurred due to the nature of individual parameters. For two laboratories, two scores revealed unsatisfactory results for concrete mix consistency. The main reasons can be pouring into the cone-shaped form a concrete mixture that is too dry, or incorrect use of a measuring tool also creating a possibility that the obtained value can be wrongly recorded. Other possible reasons are discussed in the paper. Participation in inter-laboratory comparison programmes is undoubtedly a way to verify and raise the quality of tests performed for concrete mix and hardened concrete, whereas individual analysis of the results allows the laboratory quality system to be improved.Proper quality assessment of ready-mixed concrete, which is currently the principal material for construction, land engineering and architecture, has an impact on the optimisation and verification of correct functioning of individual stages of the production process. According to the European Standard EN 206 “Concrete–Specification, performance, production and conformity”, obligatory conformity control of concrete is carried out by the producer during its production. In order to verify the quality of concrete, investors generally commission independent laboratory units to perform quality assessment of both concrete mix and hardened concrete, which guarantees a high quality of construction works. One of the essential tools for ensuring the quality of test results is the participation of laboratories in the so-called proficiency testing (PT) or inter-laboratory comparisons (ILC). Participation in PT/ILC programmes is, on the one hand, a tool for demonstrating the laboratory’s performance, on the other hand an aid for maintaining the quality of available concrete tests and validating test methods. Positive evaluation is a confirmation of the laboratory’s capability for performing the tests. The paper presents the results of laboratory proficiency tests carried out by means of inter-laboratory comparisons, as shown in the example of quality assessment of ready-mixed concrete for nine participating laboratories. The tests were performed for concrete of the following parameters: strength class C30/37, consistency S3, frost resistance degree F150, and water resistance degree W8. This involved determining consistencies, air content and density of the concrete mix, and compressive strength of hardened concrete. For the evaluation of laboratory performance results,  With the development of technology and advanced construction materials, increasingly more requirements are being imposed. Modern construction consists of structures of possibly minimal impact on the environment ,2,3, whiemission ,5,6, lowemission ,8,9, andemission ,11 or poemission ,13. Not emission ,15. Hencemission . Concretemission . Accordiemission , the woremission . It shouemission . Qualityemission ,24,25,26emission ,28,29, temission ,31. Qualemission ,33,34,35emission ,36.Concrete testing procedures and quality assurance criteria for ready-mixed concrete delivered to the construction site are fairly well-established under law, especially under industry standards. It is also important to underscore the significance and role of technical specification for execution and completion of construction works. Although appropriate industry standards contain conformity and uniformity criteria related to concrete production control, technical specifications contain, in particular, sets of requirements that are necessary for determining the standard and quality of works with regard to the manner of execution of construction works and the evaluation of correctness of execution of individual stages; these elaborations are custom-developed for each construction project .Industry standards require that the concrete supplier implement a production and quality control plan—a set of quality requirements with regard to the products and their production. The plan contains a detailed description of the manufacturing process which includes stages, organisation, methods and standards of production as well as procedures and instructions, and the testing and quality control programme ,41,42,43The aim of the present paper is the evaluation of laboratory performance by means of inter-laboratory proficiency tests as carried out for ready-mixed concrete quality assessment, for nine participating laboratory units. The most innovative element of the study was the simultaneous use of classical and robust statistical methods. In practice, the most common procedures employ classical statistical analysis, which is optimal under the assumption of normality of data distribution and large sample size. Classical statistical procedures involve, as a first step, the verification of questionable results, e.g., by applying the Grubbs test, which allows us to identify and remove abnormal values, i.e., outliers. This is only effective for large data sets, whereas for small-sized samples, removing one or several significant outliers may greatly alter the classical statistical parameters. In many fields of experimental research, particularly in destructive testing, the tests are limited to small-sized samples due to high cost intensity of the testing process. In such circumstances, it is necessary to make use of all the obtained measurement results, as removing outliers/questionable results from the sample diminishes the reliability of statistical assessment. Employing robust statistical methods is recommended, as, in comparison with classical statistical methods, they ensure a smaller impact of outliers and other anomalies on the measurement results. Quality assessment of concrete is generally carried out on the basis of small-sized samples, by means of destructive testing, without the possibility to repeat or complement the measurements. This is why iterative robust statistical methods, rarely used in concrete quality control, were proposed for the analysis of inter-laboratory comparative tests. Southern Poland-based laboratories participated in the programme voluntarily. Concrete tests and analyses were performed from June to July 2020.According to ISO/IEC 17043:2010 , laboratParticipation in proficiency testing programmes constitutes, therefore, an evaluation of a laboratory’s testing capabilities. It provides an independent, external assessment, which complements the laboratory’s internal quality control procedures. Participation in a proficiency testing programme may be a basis for self-evaluation, and contribute to improving the laboratory’s proficiency; it is, thus, an important, often obligatory element of the laboratory’s quality control system.Prior to proceeding with the testing, an appropriately designed and organised programme must be prepared in order to determine the type of analytical methods, the type of test object, and the number of participating laboratories.While preparing the test object, one should take into consideration all factors that may influence the reliability of inter-laboratory testing, such as the object’s homogeneity, the method of sample collection, the object’s stability over time, and the impact of environmental conditions (during transport and storage) on the test object’s properties. It is crucial that the material used in proficiency testing is homogenous, and that all participants are provided with test objects which do not significantly differ in terms of tested parameters. The material’s uniformity should be documented, and the conditions of its transportation and storage, and the timeframe of the testing, should be clearly defined. Test methods should be unambiguously determined and based on normalised and validated methods.ISO/IEC 17043 (2010) “Conformity assessment—general requirements for proficiency testing” ;ISO 13528 (2015) “Statistical methods for use in proficiency testing by inter-laboratory comparison” .The results obtained by the participants are subject to statistical analysis and evaluation. The methods for statistical evaluation of inter-laboratory comparison results are described in the following standards:ptx) is the value agreed on the basis of the participants’ results in the way described in ISO/IEC 17043 (2010) [Most of the methods are based on a known assigned value  , Annex B3 (2010) , Annex CAssigned value is calculated as arithmetic mean from the participants’ results, having considered the influences of outliers, with the use of robust statistical methods.u(ptx) is determined with the application of statistical method as described in ISO 13528: 2015 p.7.7.3 [p—number of participants,Standard uncertainty of assigned value  p.7.7.3  and calcS*—strong (solid) standard deviation calculated by Equation (2):i*x—results obtained by the participants after applying robust statistics,ptx—assigned value, calculated as strong (solid) mean from the participants’ results.rU) of the assigned value, with expansion coefficient k = 2 and confidence level circa 95%, is calculated by Equation (3):Expanded uncertainty :where: SD—standard deviation for proficiency test assessment, determined considering the results of all participants,Laboratory activity results are usually presented with the use of 43: 2011 , Annex Bix—result reported by the participant,x*—assigned value, determined as strong (robust) mean from the participants’ results.ζ-score (5):where: n-scoreE (6):where: z-score. By assessing a participant’s performance by means of z-score, both the trueness and precision of the obtained result are addressed [ζ-score and n-scoreE can be applied in combination with z-score as an aid for improving the laboratories’ activity [n-scoreζ-score and E depend on the participants submitting accurate measurement uncertainty estimates along with their result, a procedure not easily adhered to [The results of the laboratories’ activity are evaluated with the use of ddressed . ζ-scoreactivity ,57. ζ-schered to .z-score, ζ-score and n-scoreE is applied to all results, including those which, as outliers, were not considered in statistical calculations of the assigned value and its standard deviation. The results of actions of the programme’s participants were evaluated according to the following criteria , removing some data items (from one to three test results) significantly decreases the accuracy of uncertainty estimation, which is why the conducted analyses employed robust statistical methods, designed for robustness against slight deviation from the model (particularly the occurrence of outliers) ,57. The z-score, ζ-score and n-scoreE. On the basis of the inter-laboratory proficiency tests performed, all participating southern Poland-based laboratories which carry out tests of concrete mix and hardened concrete conduct them on a satisfactory level, as confirmed by the obtained z-score values |z| < 2.0 , both for individual employees and the entire laboratory.Z-score was applied to evaluate laboratory proficiency, whereas ζ-score and n-scoreE were used for improving the laboratories’ performance. For the laboratories defined as Lab G and Lab H, the results obtained provided information about irregularities, which made it possible to take adequate corrective measures with the aim to determine the causes of inappropriate assessment of concrete mix consistency.Comparative tests discussed in the present paper, conducted for nine participating laboratories, provided interesting data for scientific consideration. For the purpose of the tests, selected parameters/properties of concrete mix and hardened concrete were analysed. Experiences gained from the conducted tests reveal a need to continue this type of project, with the cooperation of both past participants and new laboratory facilities, for the purpose of improving the quality of activities conducted by research units. A tangible aspect of regular participation in comparative tests, with positive results, is an increase in customer trust and the evidence of the laboratory personnel’s competencies.


This guest editorial by Harris (2020)


Immunoglobulin G4-related disease (IgG4-RD) is an autoimmune inflammatory disease characterized by infiltration of IgG4+ plasma cells that can simulate a tumor manifesting as a tumor-like mass. This disease involves the pancreas, biliary tract, kidneys, salivary glands, lymph nodes, aorta, and retroperitoneum amongst other organs. However, testicular involvement is a rare entity in this disease. The treatment of testicular involvement in IgG4-RD is currently controversial. We present the case of a 65-year-old man with swelling and pain in his right scrotum three months ago. On examination, a mobile mass of approximately 2 cm in diameter was found in the right scrotum. Serological tests showed elevated levels of IgG4 and negative for tumor markers. Enhanced computed tomography of the scrotum showed a nodular hyperdense shadow with a diameter of approximately 23 mm on the right epididymis. Pathological biopsy of the right epididymis showed infiltration of plasma cells, lymphocytes, and a few neutrophils. IgG4+ plasma cells stained positive, with an IgG4/IgG ratio of more than 40% and more than 30 IgG4+ plasma cells per high-power field. A diagnosis of IgG4-RD involving the testicles was made. Prednisone 30 mg/d was given for three weeks. No scrotum swelling or pain was observed at the follow-up after six months. IgG4-related disease should be considered whenever a mass-like lesion with typical histomorphologic features involving multiple organs/anatomical sites is encountered. The testicles are an important male reproductive organ, especially for young male patients with fertility requirements. For patients with IgG4-RD testicular involvement, surgical or medical treatment requires further study. IgG4-RD is an autoimmune inflammatory disease characterized by infiltration of IgG4+ plasma cells that can simulate a tumor manifesting as a tumor-like mass . Also, IThe patient, a 65-year-old man, presented with swelling and pain in his right scrotum three months ago. He was first admitted to our hospital 5 years ago with a cough and fever. The CT scan of the abdomen showed multiple soft tissue densities behind the peritoneum and the serum IgG4 3200 mg/dL. The patient was definitively diagnosed with IgG4-RD as well as secondary retroperitoneal fibrosis by the gold standard of histopathology. He was in long-term remission after regular treatment with mycophenolate mofetil (1g Bid) and prednisone (0.6 mg/kg), followed by six months, four years, and a recent abdominal CT scan showed no progression of retroperitoneal fibrosis. He had no previous history of pulmonary or urinary tuberculosis and no significant family history. On examination, a mobile mass of approximately 2 cm in diameter was found in the right scrotum. The mass was hard and tender. No other positive signs were found. Laboratory tests showed erythrocyte sedimentation rate 69 mm/h (reference range 0-15 mm/h), C-reactive protein 29.9 mg/L (reference range 0-10 mg/L), complement C3 0.58 g/L (reference range 0.9-1.8 g/L), complement C4 0.03 g/L (reference range 0.1-0.4 g/L). Serological examination showed elevated IgG4 levels to 2070 mg/dL (reference range 6-130 mg/dL). Negative for prostate-specific antigen (PSA), tumor markers, and tuberculosis antibodies. Scrotal ultrasound demonstrating enlargement of the right testicle. Enhanced computed tomography of the scrotum showed a nodular hyperdense shadow with a diameter of approximately 23 mm on the right epididymis, with significant heterogeneous enhancement on the enhanced scan  using the following keywords: “epididymis”, “paratestis”, “testis”, “testicular”, “scrotum”, “scrotal”, “intrascrotal”, “spermatic cord, “paratesticular fibrous pseudotumor”, “paratesticular pseudotumor”, “Epididymo-orchitis”, “Immunoglobulin G4”, “IgG4”. It is worth noting that the literature was searched by two researchers, and a third researcher made the final judgment when there was disagreement. We also reviewed the articles cited in the literature to ensure the accuracy of the retrieved content. Finally, 14 articles were included in the study (IgG4-RD is a chronic progressive autoimmune disease characterized by elevated serum IgG4 levels as well as IgG4+ plasma cell infiltration of organs . The patvs 5). Testicular painlessness may be the cause of delayed diagnosis and the prolonged course of the disease. Six patients (33.33%) had no previous underlying disease and subsequently developed IgG4-RD, while four patients (22.22%) developed retroperitoneal fibrosis before the IgG4-RD involvement of the testicles. The relationship between retroperitoneal fibrosis and testicular involvement is not clarified. We hypothesize that when retroperitoneal fibrosis developed, the patient’s immune system had been attacked and no longer provided complete protection to the testicles. In terms of treatment, 16 patients (88.88%) underwent surgical treatment including partial and radical resection; only 7 patients were treated with hormone therapy (38.88%) and 1 patient was treated with methotrexate. Twelve patients were followed up and all improved.A total of 18 patients with a median age of 46 years and a mean age of 47.5 years were included in the study. There is a bimodal age distribution with a concentration of people aged 20-50 years and 70 years or older. A cohort study by Inoue et al.  enrolledSwelling and pain associated with IgG4-RD in the testis should be differentiated from testicular tuberculosis, testicular tumors, and hydrocele due to retroperitoneal fibrosis secondary to IgG4-RD. The patient had no previous history of tuberculosis of the lung or urinary tract, which effectively ruled out testicular tuberculosis. Secondary retroperitoneal fibrosis of IgG4-RD involving the ureter, inferior vena cava, abdominal aorta, and its branches, leading to hydrocele testis, can be the cause of testicular enlargement. However, after the patient was regularly treated with prednisone and mycophenolate mofetil for the first time in our hospital, retroperitoneal fibrosis was long in remission, which was confirmed by multiple abdominal CTs. Histopathologic diagnosis is still the gold standard for the diagnosis of this disease. Therefore, the patient ruled out any of these causes. The fact that this disease can mimic testicular malignancy and the inexperience of surgeons with this disease lead the vast majority of patients to receive surgical treatment. For the treatment of definitively diagnosed IgG4-RD, steroid hormone therapy that includes both inductions of remission and maintenance therapy may be more beneficial in rapidly resolving the patient’s symptomatic, biochemical, and imaging abnormalities . The tesGlucocorticoids are the first-line agents to induce remission in patients with IgG4-RD . PatientIn clinical practice, in addition to careful physical examination, when a patient has a previous diagnosis of IgG4-RD or has a localized organ enlargement suggestive of IgG4-RD morphology, complaining of testicular pain, swelling, and mass, testing the serum IgG4 level is essential as it plays a vital role in the diagnosis and monitoring of IgG4-RD recurrence . When seThis study has some limitations. Testicular involvement is uncommon, thus besides presenting the case, it is difficult to provide definitive conclusions. At the same time, the data for this study is based on published literature, which suggests that there may be more cases of testicular involvement of IgG4-RD in real life than in published literature. However, based on the existing evidence, this may provide an important reference for future research and cause for concern.vs 4), only Bösmüller et al.  for the publication of any potentially identifiable images or data included in this article.GW and NZ designed and wrote the paper. XL, FT, ZW, and JL reviewed and edited the manuscript. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


This review summarizes the current evidence around neoadjuvant radiotherapy and systemic therapy for retroperitoneal sarcoma (RPS). While surgery is the cornerstone of treatment for these tumors, data from prospective studies, retrospective studies, early phase trials, and—most recently—our first phase III randomized trial for RPS suggest there are clinical scenarios in which neoadjuvant therapy may provide benefit. This review evaluates the STRASS results in the setting of other recent studies, identifies active trials of interest, and suggests future directions of study in this field. The intersection of STRASS and STRASS2 is considered and a summary of current acceptable approaches to neoadjuvant therapy for RPS is provided. The cornerstone of therapy for primary retroperitoneal sarcomas (RPS) is complete surgical resection, best achieved by resecting the tumor en bloc with adherent structures even if not overtly infiltrated. Until recently, trials designed to elucidate the role of neoadjuvant radiation or chemotherapy for RPS have been unable to achieve sufficient enrollment. The completion of the STRASS trial, which explored neoadjuvant radiotherapy for primary resectable RPS, is a major milestone in RPS research, but has prompted further questions about histology-driven treatment paradigms for RPS. Though it was ultimately a negative trial with respect to its primary endpoint of abdominal recurrence-free survival, STRASS produced a signal that suggested improved abdominal recurrence-free survival with neoadjuvant radiotherapy (RT) for patients with liposarcoma (LPS). No effect was seen for leiomyosarcoma (LMS) or high-grade dedifferentiated (DD) LPS, consistent with recent literature suggesting LMS and high-grade DD-LPS have a predominant pattern of distant rather than local failure. These results, along with those from other recent studies conducted at the bench and the bedside, emphasize the importance of a histology-specific approach to RPS research. Recent evidence for patterns of distant failure in LMS and high-grade DD-LPS has prompted the initiation of STRASS2, a study of neoadjuvant chemotherapy for these histologies. As this study unfolds, evidence may emerge for novel systemic therapy options in specific sarcoma histotypes given the explosion in targeted and immunotherapeutic applications over the last decade. This article reviews current and recent evidence around neoadjuvant radiation and chemotherapy as well as avenues for future study to optimize these treatment approaches. Despite the rarity of soft tissue sarcomas (STS), we have made substantial strides in the study and management of these tumors in recent years. Gastrointestinal and translocation-driven sarcomas have benefitted enormously from the discovery of molecular targets and advances in targeted therapy; we are identifying histology-specific differences in sarcoma tumor microenvironments that may allow immunotherapy to change the landscape of sarcoma as it has with other malignancies; and—for the first time—we have made the successful execution of phase III trials for retroperitoneal sarcomas (RPS) a reality. Ultimately, the biggest effector of change in global sarcoma care over the last several decades has been a concerted effort toward international collaboration.While trials that are currently recruiting and on the horizon will explore various facets of neoadjuvant therapy, the majority of our evidence for RPS is still retrospective. Though collaboration has made the products of our retrospective data collection far more valuable, the heterogeneity of these tumors still makes it challenging to design prospective studies that are both meaningful and pragmatic. With no high-level evidence definitively favoring a specific approach to neoadjuvant therapy for RPS, the use of radiotherapy and chemotherapy in this setting remains variable across countries and institutions. This review discusses the current literature surrounding neoadjuvant radiotherapy and systemic therapy for RPS, as well as active trials and future directions.In the retroperitoneum, STS in general have a propensity for local recurrence (LR) rather than metastatic spread ,2. A comIn the setting of high rates of local failure, multimodality locoregional therapy may have considerable value for some patients with resectable disease . HoweverWhile STRASS was ongoing, the Transatlantic Retroperitoneal Sarcoma Working Group (TARPSWG) published a study of over 1000 RPS that demonstrated a significantly higher rate of distant failure for patients with LMS, who also had a relatively low rate of local recurrence compared with other histologic subtypes . A signiWith respect to radiosensitivity, there is no in vitro or clinical evidence available that suggests LMS is a radiosensitive histology. One in vitro study exploring multiple LMS cell lines reported considerable heterogeneity in response to radiotherapy across cell lines, with only a uterine LMS cell line demonstrating poor survival after exposure to radiation . In contIrrespective of histotype, genetic signatures may contribute to RPS radiosensitivity. This was explored in a cross-validation study of radiosensitivity with a 26-gene panel in sarcoma patients who had variable responses to radiotherapy . While dThe STRASS trial investigating neoadjuvant external beam radiotherapy (EBRT) for primary localized resectable RPS enrolled 266 patients across 31 international centers  18]. It. It18]. During STRASS’ development, histology-specific data that may have informed its design were not available, and so it was not powered to detect histologic differences in outcomes. This has ultimately led to some variance in data interpretation. There was a signal for improved ARFS in LPS patients after a sensitivity analysis whereby local progression or becoming unfit for surgery during RT were not counted towards the primary outcome as long as patients were eventually operated on. The justification of this sensitivity analysis is important to consider: the idea that pre-operative local progression is acceptable as long as it does not translate into either unresectability or an R2 resection is reasonable. Furthermore, the three patients who developed distant metastases while on RT were probably spared a morbid and oncologically ineffective operation. However, while 15 of the 19 patients who progressed while on radiotherapy still had a macroscopically complete resection, it is important to consider the possible added morbidity of a larger operation, even if a macroscopically complete resection is still achievable. Additionally, the time period between enrollment and surgery for the radiotherapy group (up to 21 weeks within the planned protocol) is substantial, and—in a post-STRASS world—may be a deterrent for both patients and providers considering neoadjuvant RT. Finally, irrespective of progression, if severe radiation-associated toxicities are precluding patients from surgery, we must think more carefully about the true benefit of neoadjuvant RT . Thirty-nine percent of the RT group in STRASS had at least a grade III complication over the course of the study. While the grade III+ complication rate in this group was only 14% pre-operatively, it is difficult to quantify the impact of radiation on post-operative morbidity.One source of controversy surrounding the STRASS trial was the variability in the initial eligibility assessment and enrollment across centers. This was revealed in the setting of the STREXIT study, an analysis of all patients who were screened using STRASS eligibility criteria at the ten top recruiting centers . STREXITWith mixed interpretations of this trial, the approach to neoadjuvant RT for RPS remains variable across institutions: centers that did not routinely use RT in the neoadjuvant setting feel their approach has been validated, while centers that favor RT continue to offer it. Some institutions that previously administered neoadjuvant RT selectively have stopped offering it to LMS patients, while considering it more consistently for WD and grade I–II DD-LPS patients. However, the same controversies regarding the true merit of neoadjuvant RT, taking into account delays to definitive surgery and significant rates of toxicity, remain.We can expect an update from STRASS in three years, which may provide more insight into late adverse events and persistent trends in survival outcomes. In the meantime, early-phase trials and other studies designed to explore the trends reported in STRASS should focus on the issues that have limited the uptake and translation of our results to date: the necessity of histology- and site-specific studies, reducing the duration of neoadjuvant therapy and subsequent delays to surgery, and mitigating or circumventing the toxicity associated with standard-course photon-based radiotherapy.The rate of tumor progression in the STRASS study, which allowed up to 21 weeks to complete standard-fractionation RT and proceed to surgery, was 16%. While most of these patients still underwent a complete resection, potential increases in post-operative morbidity and the extent of surgery related to this progression remain a concern. The incidence of progression may be mitigated by a hypofractionated approach to radiation, which delivers a greater total dose to the clinical tumor volume in fewer treatments and may get patients to surgery several weeks earlier. The benefit of this approach was recently explored in a study of neoadjuvant short-course RT in extremity and trunk sarcomas . PatientWhile there are different anatomic considerations in the retroperitoneum, the shift from standard-fractionation EBRT to short-course or hypofractionated EBRT has met with successful outcomes in rectal cancer. Multiple phase III randomized trials have demonstrated equal efficacy and reduced toxicity with short-course RT ,29. ThisDuring preoperative radiation, 14% of patients in the STRASS trial experienced a serious adverse event (grade III+), with 39% having a serious adverse event during study follow-up, and one death related to RT complications . HoweverFLASH PBT radiotherapy techniques have also been explored in preclinical studies with interesting results. FLASH RT is a form of radiation that uses electrons or protons delivered at high dose rates (>40 Gy per second) for short radiation durations ,37. CapiThe applications of PBT will only grow over the next several years. As histology-specific sarcoma trials exploring neoadjuvant RT develop, we should acknowledge PBT as an equally effective and far safer radiation modality for the treatment of RPS. Even if the value of neoadjuvant RT for radiosensitive RPS histologies can be demonstrated, safer and more effective methods of administering this radiation will be integral to the acceptance of RT as part of a neoadjuvant paradigm.While cytotoxic chemotherapy is considered standard of care for patients presenting with metastatic sarcoma, there is no high-level evidence that systemic therapy in the neoadjuvant setting confers any benefit with respect to local recurrence, distant recurrence, or overall survival for patients with resectable RPS. Trials aiming to explore neoadjuvant or adjuvant chemotherapy for STS have commonly excluded RPS or included a minority of RPS patients ,43,44,45In the absence of compelling evidence that chemotherapy improves oncologic outcomes for RPS, what are the goals of neoadjuvant chemotherapy for these tumors? First, neoadjuvant chemotherapy treats clinically undetectable micrometastatic disease, which may translate into reduced distant recurrence rates or longer disease-free intervals. It allows us to test the patient’s clinical response to standard systemic therapy regimens, which may inform treatment decisions in the event of recurrence or metastasis, as well as their histopathologic response, which has been found to correlate with survival and recurrence ,47. It eAt this time, RPS guidelines from the European Society for Medical Oncology (ESMO), European Reference Network for rare adult solid cancers (EURACAN), and Trans-Atlantic RPS Working Group (TARPSWG) reiterate the lack of evidence for neoadjuvant cytotoxic chemotherapy in resectable RPS, with caveats for a select few histologies that are discussed below ,49. WhenOutside the traditional cytotoxic chemotherapy paradigm, applications of targeted therapy and immunotherapy in other cancers are expanding. With a growing understanding of the heterogeneous immune signatures across sarcomas and encouraging findings from in vitro studies exploring common RPS gene expression profiles, the role for these therapies in RPS is likely to expand significantly in the coming years. This section reviews existing literature and active trials for cytotoxic therapy, targeted therapy, and immunotherapy in RPS.When chemotherapy is indicated for RPS, most commonly in the unresectable or metastatic setting, standard first-line therapy is an anthracycline-based regimen (doxorubicin or epirubicin), often with ifosfamide +/− mesna. Doxorubicin + dacarbazine is commonly used in LMS. Single-agent doxorubicin or gemcitabine + docetaxel are other acceptable regimens, although gemcitabine and docetaxel are not traditionally recommended as first-line therapy since this combination has worse toxicity than doxorubicin alone with no added benefit . Other sThree previous systematic reviews have evaluated the role of chemotherapy in treating STS, with the most recent including cohort studies as well as randomized trials ,52,53,54Since no trials to date have evaluated systemic therapy in the neoadjuvant setting for RPS alone, any prospective evidence we have is extrapolated from extremity and trunk populations, which have different patterns and mechanisms of local recurrence and distant spread. One European Organization for Research and Treatment of Cancer (EORTC) phase II trial explored neoadjuvant chemotherapy for high-risk adult STS excluding RPS. They defined ‘high-risk’ as ≥8 cm, locally recurrent, or grade II/III . Their pp < 0.01) . It. It71]. The histologic inclusion criteria for this study were based on patterns of distant failure observed in DD-LPS and LMS patients at participating centers ,72. The As with other rare diseases, clinically actionable molecular targets in sarcoma have the potential to change the landscape of the disease. This is perhaps most evident in gastrointestinal stromal tumors (GIST), for which targeted therapy in the form of imatinib has made sweeping changes to our treatment paradigm, including in the neoadjuvant setting. With respect to retroperitoneal tumors, studies identifying unique gene expression profiles of common RPS histotypes such as LPS have been encouraging but have not yet been translated into therapeutic targets. The ultra-rare mesenchymal tumors for which molecular targets are being clinically investigated (such as PEComas) are unfortunately uncommon in the retroperitoneum.Pazopanib, a multiple TKI that targets VEGFR and PDGFR, is approved as a second-line agent for advanced STS but is not considered to be an appropriate neoadjuvant agent for any of the common RPS histologies. Among all-comers with STS, it has shown the greatest efficacy in LMS and solitary fibrous tumors (SFT), among others. In the initial phase II study of pazopanib for STS, all but 26% of patients with adipocytic tumors/LPS had experienced tumor progression at 12 weeks, and therefore the LPS stratum was closed . HoweverThere is currently no established role for immunotherapy in the neoadjuvant setting for RPS. One phase II trial explored the benefit of the anti-PD-1 therapy pembrolizumab in patients with metastatic STS treated with multiple previous lines of therapy (SARC028) . They deAs would be expected, immunobiology across STS subtypes varies dramatically. Though sarcomas were previously considered immunologically inert (‘cold’), we are now discovering that certain subtypes are consistently immunologically responsive (‘hot’) and may be effectively targeted with immunotherapy. Mechanisms accounting for this were explored in a study evaluating the tumor microenvironment (TME) in classically ‘cold’ rhabdomyosarcoma (RMS) and ‘hot’ UPS, as well as LMS . This stPD-L1 expression levels have been correlated with anti-PD-1 treatment response in other cancers and will be an important pillar of translational research as we pursue effective applications of immunotherapy in specific sarcoma subtypes ,84,85,86A French phase II trial (TORNADO) with planned enrollment starting in 2022 will investigate the effect of neoadjuvant chemotherapy and retifanlimab on histologic response for previously untreated resectable RPS of any histology (NCT04968106) . RetifanIn one active phase II trial exploring neoadjuvant nivolumab +/− ipilimumab for resectable retroperitoneal DD-LPS, patients will receive five weeks of upfront immunotherapy (three doses) prior to surgical resection . The priFinally, though immunotherapy has changed the face of a number of cancers, the rarity of STS has slowed our entry into this field of investigation. Our increasing understanding of the heterogeneous immune signatures of various STS and growing collaborative tissue repositories will likely inform the design of forthcoming studies, enabling patients with a subset of sarcomas to benefit substantially from immunotherapy.Although myxoid LPS is not a retroperitoneal histology, it has demonstrated an impressive response to multimodal therapy in recent early-phase clinical trials. In the setting of an established response to both trabectidin and radiotherapy, myxoid liposarcoma—previously treated with anthracycline-based chemotherapy in keeping with the standard of care for other LPS—was investigated in the TRASTS trial, a study of three cycles of neoadjuvant trabectidin and 45 Gy RT. Phase I of TRASTS demonstrated a good safety profile and anti-tumor activity . In the mdm2 gene is the most commonly recognized abnormality in LPS. MDM2 suppresses downstream p53 function, and so MDM2 inhibition is only an effective strategy for p53 wild-type tumors. A recent study also identified an activating PIK3CA mutation across several LPS samples [With a trend toward improved ARFS in LPS patients receiving neoadjuvant RT in STRASS, and STRASS2 exploring chemotherapy for high-risk LMS and DD-LPS, therapies that serve to enhance the effects of traditional RT or chemotherapy agents will be important to explore. Overexpression of the mouse double minute 2 homolog (MDM2) protein from amplification of the  samples . Treatme samples .With respect to targeting MDM2 amplification, experimental agents have shown promise in proof-of-concept studies and early trials. ,93. WhilThe SARC028 findings prompted a phase II study of neoadjuvant pembrolizumab in concert with RT for UPS and LPS of the extremities (SU2C-SARC032), which has now completed accrual . Though As we see long-term outcomes from STRASS, anticipate histology-specific neoadjuvant radiotherapy trials in the future, and interpret data from ongoing early-phase trials of other approaches to RPS, the additive role of immunotherapy for susceptible subtypes in the neoadjuvant setting will be essential to explore.The histologic subgroup analyses for STRASS2 will be the most important aspect of this new trial: compelling evidence for a chemotherapy effect in LMS, DD-LPS, or both would have to be demonstrated to prompt a shift in our neoadjuvant paradigm, which—until STRASS2 enrollment—uncommonly included systemic therapy for upfront resectable tumors. If this trial demonstrates a positive result for DD-LPS, then this evidence, in conjunction with the clinically compelling findings in the STRASS and STREXIT data, may open up a new line of investigation for multimodality neoadjuvant treatment in DD-LPS. As has been the case with other solid tumors that have moved toward a total neoadjuvant treatment paradigm, an important line of study will be minimizing delays to surgery after integrating RT and chemotherapy. The results of STRASS2 may also inform the design of new neoadjuvant protocols generated from our growing understanding of novel therapies. Current approaches to neoadjuvant treatment, considering the background evidence supporting these trials, are depicted in The rate of progression in STRASS1 was high (16%). However, all but one of these patients either had a complete macroscopic resection despite local tumor progression or else went on to develop distant metastases and would have likely failed in the early post-operative period regardless. In addition to sparing patients an unnecessary operation, similar findings in STRASS2 would have the advantage of testing tumor biology with early first-line chemotherapy and positioning them to receive appropriate subsequent treatment at a time when they have a low metastatic burden.Determining the role of neoadjuvant chemo- or radiotherapy in RPS is challenging, especially given the difficulty of achieving sufficient enrollment in clinical trials to generate meaningful conclusions. Recent international collaborations have allowed us to develop valuable prospective registries, analyze large and granular retrospective cohorts, and complete the first successful phase III trial in RPS. While STRASS raised a number of questions, it does provide compelling evidence for histology-specific variations in local control for RPS, with a signal for improved ARFS in low-grade LPS. High-grade RPS with a tendency toward distant failure will be enrolled in STRASS2 to explore the impact of neoadjuvant anthracycline-based chemotherapy in this population. As long-term results from these studies unfold, we can also expect ongoing progress in the fields of radiation, targeted therapy, and immunotherapy to add to our existing body of evidence for various RPS histologies. As these arise, continued collaborative efforts will enable us to progress towards optimizing our treatment approaches for these rare cancers.


The risk factors associated with metabolic syndrome (Met-S) including hypertension, hyperglycemia, central obesity, and dyslipidemia are preventable, particularly at their early stage. There are limited data available on the association between Met-S and preventable risk factors in young adults. We randomly selected 2,010 Saudis aged 18–30 years, who applied to be recruited in military colleges. All the procedures followed the guidelines of International Diabetes Federation. The results showed that out of 2,010 subjects, 4088 were affected with Met-S. The commonest risk factors were high blood sugar (63.6%), high systolic and diastolic blood pressures (63.3 and 37.3%), and high body mass index (57.5%). The prevalence of prediabetes and diabetes were 55.2 and 8.4%, respectively. Obesity, diabetes, hypertension, and hypertriglyceridemia were significantly associated with Met-S. The frequency of smoking was significantly linked with the development of Met-S. The prevalence of Met-S was found to be significantly higher in individuals with sedentary lifestyle. In conclusion, the results of this study clearly indicate that military recruits, who represent healthy young adults, are also prone to Met-S. The findings of this study will help in designing preventive measures as well as public awareness programs for controlling the high prevalence of Met-S in young adults. ThereIn fact, by identifying persons at risk of developing CVD and supplying early health counseling and lifestyle interventions, it could be possible to prevent later detrimental cardio-metabolic diseases. The unhealthy change in dietary habits, a sedentary lifestyle, and consanguineous marriages make the young Saudi population vulnerable to Met-S. The influence of diet, PA, and BMI on the body composition of adolescents and young adults has been studied previously ,9,11. Ho2This study was conducted on a total of 2,010 young Saudi men, aged 18–30 years, who applied for recruitment to Saudi armed forces. The study was carried out at the health facility of the selection centers and all the selected participants individually completed a consent form. Standardized medical observations included physical examination as well as measurements related to Met-S including BP, height, body weight, and blood biochemistry (blood glucose and lipid profile). The complete information of each participant was filled in a specially designed questionnaire based on the guidelines of the World Health Organization (WHO) [According to the International Diabetes Federation (IDF) definition, subjects were considered to have Met-S if they had central obesity (defined as waist circumference >94 cm), plus two of the following four factors. Raised fasting plasma glucose >100 mg/dL (5.6 mmol/L), or previously diagnosed type-2 diabetes; systolic BP >130 mm Hg or diastolic BP >85 mm Hg, or treatment of previously diagnosed hypertension; high density lipoproteins (HDL) <40 mg/dL (1.0 mmol/L) or specific treatment for this lipid abnormality; and triglycerides (TGs) level >150 mg/dL (1.7 mmol/L) or specific treatment for this lipid abnormality.2), overweight (≥25–29.99 kg/m2), and obese (≥30 kg/m2) , total cholesterol, HDL, and TGs were analyzed using a Hitachi 902 autoanalyzer .Blood samples from each recruitment center were transported to Prince Sultan Military Medical City for biochemical analysis. Blood samples were centrifuged at 1,500×t-test were used for comparison between the Met-S and without Met-S groups. Analysis of covariance with age-adjusted means was used to evaluate the association between Met-S component factors and different parameters. A two-tailed P value <0.05 was considered as statistically significant.The data were analyzed by using the statistical package for the social sciences (SPSS) statistical package version 14 . Mean and standard deviation were calculated for parametric data, whereas categorical data were represented by number and percentage. The chi-square test and student 33.1P < 0.001). The prevalence of Met-S was higher in subjects with primary education than those with secondary education (P < 0.001). Married subjects showed high frequency of Met-S as compared to unmarried participants (P < 0.01). Subjects coming from large families (>15 members) had significantly higher prevalence of Met-S (P < 0.05). Monthly income did not show any association with Met-S  and obese (42.87%) subjects showed significantly high incidences of Met-S (P < 0.001) frequency of Met-S as compared to subjects with normal BP. There was a direct association between FBS and Met-S. The prevalence of Met-S was highest in diabetic subjects (42.6%) followed by prediabetics (32.34%) as compared to subjects with normal FBS  and of the same magnitude , whereas an early cessation of smoking significantly reduced the incidence of Met-S (P = 0.002). Although the use of smoke-less tobacco (SLT) was not associated with Met-S, the rate of consuming SLT showed a significant direct association with Met-S (P = 0.001). Passive smoking was reported by 14% subjects; however, there was no significant association between passive smoking and Met-S  were smokers. We observed a significant association between type of tobacco and Met-S . Age at nd Met-S .3.4P = 0.411 for fruits and P = 0.435 for vegetables) with the prevalence of Met-S in subjects  did not reveal any association between PA and Met-S . Moreover, the time spent is rigorous sporting activity also showed a significant association with Met-S  association with Met-S  and obesity (46.21%) in our study population . The higAlthough we did not observe a significant association between intake of fruit and vegetables (F&V) and Met-S , it has In this study, the mode of tobacco use was significantly associated with Met-S . The gloWe observed a significant role of PA in the development of Met-S. A high prevalence (70%) of physical inactivity has been reported in individuals from gulf countries . PotentiIt is important to note that many risk factors become more damaging when they occur in combination with one another. Most of these risk factors are avoidable and can easily be managed by lifestyle changes. Modifiable risk factors, including hypertension, smoking, diabetes, obesity, dyslipedemia, stress, unhealthy diet, and physical inactivity, are the major contributors to cardiovascular morbidity and mortality. These risk factors rarely occur alone, and instead tend to cluster in individuals . The preIn conclusion, Met-S is prevalent in young military recruits, which is a matter of great concern. Several demographic factors such as age, education, marital status, and family size were significantly associated with Met-S. The component factors of Met-S including BMI, BP, blood sugar, TGs, and HDL showed highly significant association with Met-S. Most of these factors are preventable and can be controlled by modifications in dietary habits and PA. Although MPA was not very effective in reducing Met-S, rigorous physical work and sport activities significantly reduced the incidence of Met-S. These findings will help in designing preventive measures as well as public awareness programs for controlling the high prevalence of Met-S in young adults.


A hypothesis was put forward that a nano-modifying additive of micro silica, which had a beneficial effect on achieving a perfect structure of heavy concrete, can also be effectively used in lightweight fiber-reinforced concrete. The nano-modifying additives of micro silica application in manufacturing lightweight fiber reinforced concrete products and structures can significantly enchain their strength characteristics without increasing their mass and consequently improve their design characteristics. The purpose of the work was to increase the structural quality coefficients for all types of strengths of lightweight fiber-reinforced concrete due to its modification with micro silica. The effect of nano-modifying additives of micro silica on the strength characteristics of lightweight fiber reinforced concrete was studied. The optimal amount of micro silica addition was experimentally confirmed and established of 10% of the cement mass. The coefficients of constructive quality for all experimentally determined strength characteristics of lightweight fiber-reinforced concrete modified with micro silica additives were calculated. The coefficient of constructive quality for tensile strength in bending of lightweight fiber reinforced concrete with additives was two and a half times higher than that of heavy concrete without additives and up to 37% higher than that of lightweight fiber-reinforced concrete without additives. Water was activated by electric, magnetic fields, gravity, or other methods [Among the innovative areas that improve the efficiency of cement materials are their fine grinding, activation of water and mortars, reinforcement with fillers, etc. ,2. Fine  methods ,2. Considerable attention of researchers is paid to the use of production waste during new construction materials obtaining. At the same time, the following tasks are considered: environmental protection, involvement of waste in the production of building materials to reduce the consumption of cement and improve the economic performance, improving the quality of building materials, including their operational resistance and durability, creation of waste-free technologies to produce building materials. Furthermore, the structural health monitoring techniques can investigate their condition to ensure the safety of the infrastructure during its service life ,4,5.The finely dispersed technogenic and natural raw materials application in building manufacture is due to both factors: the need large-tonnage production wastes utilization , and the requirement to improve the quality of building materials ,7,8. TheThe following methods can be used to increase the efficiency of cement use and reduce energy consumption in the manufacture of concrete: the inclusion of additives of micro-fillers, including micro silica and reinforcing fillers such as wollastonite; the introduction of superplasticizers; mechanical activation of cement; the impact of electromagnetic waves ,10,11.When non-functional organosilicon compounds and superplasticizers are used as additives, their mechanical activation is expedient. In this case, polyorganosiloxanes can enter into a chemical reaction with cement minerals, resulting in heterosiloxane structures that are resistant to the action of alkalis .For example, in , the curReducing the amount of clinker in cement binders is very important today, and nanotechnology allows to expand these opportunities. So, in work  the optiThe need to produce environmentally friendly cement has driven research towards nanotechnology. The main product of cement hydration—calcium silicate hydrate—is nanoscale in nature. Therefore, the addition of nanoparticles to mixed compositions of Portland cement can significantly change the mechanical strength, porosity and durability. The work  consider2(nS) particles on cement binders was studied. NS particles dispersed in (a) polycarboxylate or (b) water were added to a reference low carbon binder containing 43% Portland cement (PC), 20% limestone powder (LS) and 37% fly ash (FA) by weight binder. Eight quaternary binders containing nS, PC, LS and FA and eight quaternary binders containing nS, PC, LS, FA and micro silica (μS) were then tested. nS was added in an amount of 0.1%, 0.2%, 0.5% or 1.0% by weight of the binder as a substitute for LS for four-component binders and in an amount of 0.5% or 1.0% for five-component binders. It was concluded that, in such complex compositions, hydration products seem to create a shell around FA particles, delaying their activation at an early age. At a later age, the addition of 0.5% nS improved strength, microstructure and hydration. Polycarboxylate/nS particles provided a more pronounced improvement in strength with the addition of 0.5%, possibly due to their superplasticizing effect [In , the effg effect .A study  evaluateIn , an asse2, which are located in the interfacial zone (ITZ) between the hardened cement paste and aggregates and form a C-SH gel and the filling action of nanoparticles, which form a more compacted microstructure. A total 3% of nanoparticles, consisting of 25% NS and 75% NC, gave the highest mechanical properties: compressive and flexural strength [In the article , a studystrength .Polypropylene fibers with carbon nanotubes obtained by melt spinning were analyzed in  from theThe effect of microstal fiber, granular light fly ash aggregate and microsilica content on the fresh and hardened properties of a high-performance binder composite (HPCC) has been experimentally investigated . The mecAnalysis of literature data ,27,28,29A hypothesis was put forward that a nano-modifying additive, which has a beneficial effect on achieving a perfect structure of heavy concrete, can be simultaneously used in lightweight fiber concrete. It is assumed that the use of nano-modifying additives of micro silica in the technology of manufacturing lightweight fiber-reinforced concrete products and structures will significantly increase their strength characteristics without increasing their mass and, as a consequence, improve their design characteristics.Scientific novelty: for the first time, studies were carried out to increase the coefficients of the constructive quality of lightweight fiber-reinforced concrete due to its modification with micro silica.Purpose of the work: increasing the coefficients of constructive quality for all types of strengths of lightweight fiber-reinforced concrete due to its modification with micro silica. Experimental studies were carried out following the structural and methodological scheme shown in After formulating the hypothesis, scientific novelty, substantiating the relevance, identifying the goal, and setting goals, we will determine the necessary set of materials, equipment, and methodological apparatus for conducting the experimental and analytical part of the study.During the research, additives-free Portland cement of the PC 500 D0 brand was used, the physical and mechanical characteristics and chemical composition of which are presented in Granite crushed stone was used as a sizeable dense aggregate, and slag pumice was used as a porous one. The physical and mechanical characteristics of a large dense and porous aggregate are presented in Quartz sand was used as a fine aggregate, the physical characteristics of which are presented in For sieves with a mesh size of 2.5, 1.25, 0.63, 0.315 and 0.16, the grain size composition of the sand is given, where the upper line is the partial sieve rest, and the lower line is the full sieve rest.Glass fiber pretreated with surfactant was used as dispersed reinforcement. Micro silica grade MS-85 was used as a reaction-chemical pozzolanic additive. Polycarboxylate superplasticizer MELFLUX 5581 F manufactured by BASF Construction Additives  was used as a plasticizing additive in an amount of 0.3% by weight of cement.As a control composition, heavy concrete of class B30 was designed with the workability of the mixture corresponding to the draft of the cone 1–4 cm . The parDuring the manufacture of lightweight fiber-reinforced concrete, part of the volume of dense aggregate was replaced with the same volume of porous in an amount of 40%. Glass fiber was introduced in the amount of 3% by weight of the cement. The water consumption was adjusted until the required concrete mix mobility was obtained .When dispersed mineral additives are introduced, their uniform distribution over the volume is very important, especially in the case of the manufacture of heavy and lightweight concretes ,34.The mixture of powders was processed in a homogenizer to increase the homogeneity of the binder (cement and additives).Homogenization of Portland cement and micro silica was carried out in a planetary ball mill “Activator-4M”. General view of the planetary ball mill “Activator-4M” is shown in F/dBd < l is considered favorable when the filler particles serve as a substrate onto which the products of neoplasms diffuse. In this case, diffusion is possible both through the dispersion medium and through the surface of the solvation shells. Furthermore, the outflow of the substance into the contact zone prevents the early overlap of the surface of the binder grains by nuclei, which should cause a deepening of the hydration processes.For the directed organization of the microstructure of the cement stone, the ratio of the diameters of the mineral additive (filler) and the binder Determination of the granulometric characteristics of powdery raw materials  was carried out using the method of laser granulometry. This method allows to determine particles size and their percentage in the material, as well as to study their shape and morphology.Microsizer 201C laser particle analyzer was used to carry out the particle size analysis of the mineral components. It is a fully automated device designed for fast and accurate measurement of particle size distribution in the range of 0.2–600 µm. The general view of the device is shown in The study of the microstructure was carried out on a VEGA II LMU scanning electron microscope  at an accelerating voltage of 20 kV.Images were obtained using SE detectors. The SE (Secondary Electron) detector provides information on the surface morphology of the sample. The BSE detector (reflected or backscattered electrons) provides information about the phase and chemical inhomogeneity of the material (phases and areas with a higher average atomic weight are colored in lighter shades). The surface of the samples was sputtered with metal in an Emitech sputtering device.The experimental research program is presented in −technological equipment: laboratory concrete mixer BL-10 ; laboratory vibrating platform SMZh-539-220A ;−testing equipment: hydraulic press IP-1000 ; tensile testing machine R-50 ;−measuring instruments: measuring metal ruler 500 mm; laboratory scales; device for measuring deviations from the plane NPL-1; device for measuring deviations from perpendicularity NPR-1.Also used in this research:In the course of the study, standard test methods for raw materials and products based on them were used.Compressive and tensile flexural strength tests were carried out by GOST 10180 “Concretes. Methods for strength determination using reference specimens” .When testing for compression, sample cubes are installed with one of the selected faces on the lower base plate of the testing machine (press) centrally relative to its longitudinal axis, using the marks drawn on the plate of the testing machine.After placing the sample on the support plates of the testing machine, align the top plate of the testing machine with the upper support face of the model so that their planes adjoin entirely one another. The sample is loaded to failure at a constant rate of load rise (0.6 ± 0.2) MPa/s.The prism specimen is installed in the testing machine according to When testing for axial tension, the sample is fixed in a tensile machine and loaded to failure at a constant rate of load growth (0.05 ± 0.01) MPa/s.The prismatic strength was determined following the requirements of GOST 24452 “Concretes. Methods of prismatic, compressive strength, modulus of elasticity and Poisson’s ratio determination” .When determining the prismatic strength of concrete, loading the specimen to a load level equal to (40 ± 5)% should be performed in steps equal to 10% of the expected breaking load, keeping the loading rate (0.6 ± 0.2) MPa/s.At each stage, load should be held for 4 to 5 min (during heating-up to 15 min) and the readings on the instruments at the beginning and at the end of the load stage should be recorded in the test log.At a load level equal to (40 ± 5)%, remove the instruments from the sample, unless there are other requirements stipulated by the test program. After removing the devices, further loading of the sample should be carried out continuously at a constant speed in accordance with the requirements of GOST 10180-2012.CSQ) for different types of strengths were calculated using the following formulas:ρ is the density of concrete, g/cm3.The values of the coefficients of constructive quality  is a substance that has a loose structure and can dissolve in water, therefore it does not play an important role in increasing the strength and durability of concrete.Clinker hydration products with a low degree of crystallinity increase the strength of the cement stone. Therefore, to increase the density of cement stone, it is necessary to create such a structure that contains many fine-crystalline “internal products”  CSH see .The addition of silica fume binds free Using the method of electron microscopy, a comparative analysis of the effect of micro silica and a complex of micro silica (MS) + superplasticizer (SP) on the formation of the structure and properties of cement stone was carried out. Pictures of the main compositions are shown in -the structure of non-additive cement stone is heterogeneous, has a block character and is represented by weakly crystallized interlayers of highly basic calcium hydrosilicates, including portlandite accumulations;-the addition of MS contributes to the formation of a denser homogeneous structure, preferably from low-basic calcium hydrosilicates;-the joint introduction of MS and SP is accompanied by the formation of a dense structure, represented by both a weakly crystallized and a gel-like phase, in which portlandite is practically not detected.Thus, the study of cement stone chips in an electron microscope made it possible to draw the following conclusions:The results obtained from the tests of prototypes of lightweight fiber-reinforced concrete with different percentages of micro silica are presented in -the maximum germination of cubic strength is observed in the prototypes of lightweight fiber-reinforced concrete with a micro silica content of 10% (MS = 10%); so in comparison with samples of lightweight fiber-reinforced concrete without additives, it was 35%; a similar comparison was made for other compositions: so the increase for samples with MS = 6% was 17%, for samples with MS = 8–23%, for samples with MS = 12–25%;-the increase in prismatic compressive strength for specimens with MS = 6% was 16%, for specimens with MS = 8–25%, for specimens with MS = 10–35%, and for specimens with MS = 12–26%;-the increase in tensile strength in bending for specimens with MS = 6% was 12%, for specimens with MS = 8–17%, for specimens with MS = 10–37%, and for specimens with MS = 12–24 %;-the increase in axial tensile strength for specimens with MS = 6% was 8%, for specimens with MS = 8–16%, for specimens with MS = 10–24%, and for specimens with MS = 12–10%.After analyzing the obtained experimental data on the effect of the percentage of micro silica additive on the strength characteristics of lightweight fiber-reinforced concrete, the following was established:▪▪▪▪So, in comparison with heavy concrete, the increase was:▪-▪-▪-▪-In comparison with lightweight concrete without MK-85 additive, the increase was:CSQ) for tensile strength in bending for lightweight fiber-reinforced concrete with MS = 10% is two and a half times higher than that for heavy concrete without additives due to the complex influence of the following factors:(1)the addition of fiber, which significantly increases the tensile strength in bending.(2)replacement of a part of the dense aggregate with a porous one, which leads to a significant reduction in the mass of concrete products with a slight loss of strength;(3)replacing part of the cement with lighter micro silica.The coefficient of constructive quality (After carrying out experimental studies, processing the results obtained and performing the necessary calculations, as well as after completing the theoretical interpretation with the help of high-precision microscopic equipment of the physical picture of the processes of structure formation, a thorough analysis and comparison of the results obtained with the results of other authors should be carried out.The analysis of the results obtained showed the high efficiency of the proposed recipe, technological and design solutions. From the formulation point of view, the possibility of nanomodification of lightweight fiber-reinforced concrete with micro silica was established, as a result of which, firstly, the expediency of such nanomodification, and secondly, the dosage of the content of nano-modifying additives of micro silica in such concrete was determined to obtain the highest characteristics.From a technological point of view, the compatibility of low-density dispersion-reinforced concrete with a nano-modifying additive of micro silica was tested. The revealed possibility of simple technological mixing of such components and the test results proved that the joint work of fiber-reinforcing fiber and hardening micro silica is beneficial to the resulting concrete and gives a synergistic effect.From a constructive point of view, the possibility of dispersed reinforcement of such lightweight fiber-reinforced concrete, which, in turn, at the level of a cement stone, is nano-modified with the addition of micro silica, was determined.This is how you can describe the qualitative picture of the study.From a quantitative point of view, it was revealed that the optimal value of the percentage of nano-modifying additives of micro silica will be a value equal to 10%.At the same time, the mechanism of interaction between the nano-modifying additive and the structure of the forming concrete has been studied. A high packing density of particles in such concrete was proved, and the addition of micro silica contributed to better hydration of the cement stone, its more perfect structure, and a decrease in pore space. Such an additive influenced the pore structure at the micro level, while an important factor was the simultaneous dispersed reinforcement of concrete, which ultimately turned out to be light in weight and at the same time possessing significant strength compared to analogs. In order to identify operational prospects, it was also necessary to evaluate the effectiveness of the proposed recipe, technological and design solutions not in terms of absolute indicators, but in terms of relative ones, in terms of the coefficient of constructive quality. Their effectiveness was proved due to the fact that the coefficient of constructive quality increased due to a significant increase in strength, while the mass of structures practically did not change from the introduction of a nano-modifying additive.To assess the effectiveness of the developed proposals, it is important to conduct a comparative analysis with the results previously obtained by other authors. As already noted in the Introduction section, various authors ,27,28,29The novelty of the research is the application of such a combined modification of concrete at the micro and macro levels, and thus the research is original, different from the previously performed works.For the first time, we obtained new fundamental knowledge about the formation of the microstructure of fiber-reinforced concrete with a lightweight of nanomodified micro silica additive and developed ideas about the joint work of nanomodified cement stone with dispersed fiber in lightweight fiber-reinforced concrete with an increased coefficient of structural quality.According to the results of the literature review and analysis of sources devoted to research carried out on the topics of nano-modified concretes, it was revealed that studies aimed at increasing the coefficients of the constructive quality of lightweight fiber-reinforced concrete due to its modification with micro silica were not carried out earlier.The effect of nano-modifying additives of micro silica on the strength characteristics of lightweight fiber-reinforced concrete was theoretically and experimentally established. Thus, the introduction of micro silica additive into Portland cement, having an average grain size of 3.6 μm, in an amount of 10% of the cement mass in combination with a superplasticizer, is the most effective. This effect of the additive is due to the fact that it acts, as it were, as a substrate for the crystallization of hydrated neoplasms.Large-scale experimental studies were carried out, compositions were selected, new samples of materials obtained for the first time were molded.It is proposed to evaluate the effectiveness of each accepted recipe-technological solution in terms of relative indicators—the calculated values of the structural quality coefficients for all experimentally determined strength characteristics of lightweight fiber-reinforced concrete modified with the addition of micro silica. The coefficient of constructive quality for tensile strength in bending of lightweight fiber-reinforced concrete with MK = 10% is two and a half times higher than that of heavy concrete without additives and up to 37% higher than that of lightweight fiber-reinforced concrete without additives.The results obtained are recommended for practical application in construction and design, and are also the basis for further scientific fundamental and applied research.


In this paper, a new polyhedral oligomeric silsesquioxane containing a phenol group (POSS-Phenol) is prepared through the Michael addition reaction, which is added to the synthesis of phenolic resin as a functional monomer. Infrared spectroscopy (IR) is used to demonstrate the chemistry structure of the synthesized POSS modified phenolic resin. After introducing POSS into the resole, a comprehensive study is conducted to reveal the effects of POSS on the thermal degradation of phenolic resin. First, thermal degradation behaviors of neat phenolic resin and modified phenolic resin are carried out by thermogravimetric analysis (TGA). Then, the gas volatiles from thermal degradation are investigated by thermogravimetric mass spectrometry (TG-MS). Finally, the residues after thermal degradation are characterized by X-ray diffraction (XRD). The research indicates that POSS modified phenolic resin shows a better thermal stability than neat phenolic resin, especially at high temperatures under air atmosphere. On the one hand, the introduction of the POSS group can effectively improve the release temperature of oxygen containing volatiles. On the other hand, the POSS group forms silica at high temperatures under air, which can effectively inhibit the thermal oxidation of phenolic resin and make phenolic resin show a better high-temperature oxidation resistance. Phenolic resin is an indispensable foundational material in the field of aerospace thermal protection materials due to its excellent thermal stability, solvent resistance and structural integrity, and it is also a precursor of C/C composite materials ,2. HowevIn recent years, nanotechnology has been widely used in polymer modification. The volume effect, surface effect and quantum size of nanomaterials have made significant breakthroughs in modified phenolic resins, such as increasing the heat resistance, ablation resistance and thermal insulation ,9. Polyh2 layers formed after the degradation of POSS have a good heat oxygen effect, which will greatly improve the thermal oxidation resistance of phenolic resin [Introducing POSS into the cross-link network structure of phenolic resin by means of a chemical bond can avoid the universal reuniting of nanoparticles, which can improve the glass transition temperature and residual char yield of phenolic resin. In particular, in extremely high temperature conditions, the SiOic resin ,20.2–) groups; In the second stage (300–800 °C), the methylene and ether bonds are broken to produce main products such as methane, hydrogen and carbon monoxide; In the third stage (800 °C–), hydrogen atoms are separated from the carbon skeleton to generate hydrogen and a continuous network of glassy carbon structure.At present, the research work on phenolic resin mainly focuses on chemical modification and the synthesis process, while the thermal degradation study of modified phenolic resin has been less reported. As an important thermal protective ablation material substrate, the degradation properties of modified phenolic are closely related to its application under a high-temperature ablation environment . On the In this article, we used the hydrolysis and condensation of trimethoxysilane to prepare POSS-8SH. Then, the POSS-8Phenol, which contains octagonal phenol, was synthesized through a mild and efficient Michael addition reaction between sulfhydryl and double-bonded C=C. After this, POSS-8Phenol, as a special phenol, was introduced into the molecular structure of thermoset phenolic resin. The chemical structure of POSS modified phenolic resin was studied by IR. The thermal degradation behaviors of POSS modified phenolic resin were respectively studied by TGA under argon and air. Moreover, the volatiles and residues of POSS modified phenolic resin were characterized by TG-MS and XRD in order to further understand the degradation mechanism. Neat phenolic resin was fabricated into a subsample and investigated with the same analysis process.(3-mercaptopropyl) trimethoxysilane (MPT), dibutylamine was purchased from Aladdin Reagent Co., Ltd. . Phenol, 37% aqueous solution of formaldehyde, sodium hydroxide, methanol, acetone, dichloromethane, hydrochloric acid, anhydrous magnesium sulfate and sodium chloride were purchased from Sinopharm Chemical Reagent Co., Ltd. . N-(4-hydroxyphenyl) maleimide (HPM) was purchased from Weng Jiang Reagent Co., Ltd. . All the chemicals were used directly without further purification.2Cl2 was evaporated under vacuum.Synthesis of POSS-8SH: POSS-8SH is prepared via a dehydration condensation reaction of trimethoxysilane, according to the literature methods ,23. BrieSynthesis of POSS-8Phenol: The synthesis of POSS-8Phenol occurred through the Michael addition reaction between the sulfhydryl group and the electron-deficient double bond of the maleimide group under the catalysis of an organic base ,25,26. 3Preparation and curing of POSS modified phenolic resin: 50% NaOH aqueous solution was used to catalyze the synthesis of thermosetting phenolic resin, in which the molar amount of NaOH was 1% of phenol. 94.10 g (1 mol) phenol, 12.66 g (0.005 mol) POSS-8phenol, and 126.95 g of 37% formaldehyde aqueous solution  were blended with a 250.00 mL flask equipped with stirring and reflux. The mixed solution was heated to 70 °C for 2 h, then heated to 95 °C for 20 min and dehydrated for 30 min after holding for 1 h. The obtained modified phenolic resin was about 130.00 g. The synthesis steps of the neat phenolic resin were consistent with the above process, except for POSS-8phenol. The obtained neat phenolic resin was about 150.00 g. Both phenolic resins were placed in the closed molds with an external pressure of 10.00 MPa, and the cured procedure was at 80 °C (4 h)/120 °C (2 h)/180 °C(4 h).−1 to 4000 cm−1 by a Nicolet Nexus IR Spectra, . The thermal stabilities of POSS modified phenolic were characterized by thermogravimetric analysis  under argon and air. The TGA sample was about 5.00 mg and was heated at temperatures of 50~850 °C at a constant heating rate of 10 °C/min. The flow rate of argon was about 50.00 mL/min. The degradation volatiles of POSS modified phenolic resin were studied by thermogravimetric mass spectrometry  under argon and air, and the heating process was the same as that of TGA. For the TG-MS measurements, about 4.00 mg of the sample was taken onto a platinum pan, and the scanned mass range was m/z = 1.6–100. After determining the target species, the final measurements were performed by setting the mass spectrometer at the selected ion monitoring (SIM) mode. The phase compositions of the POSS modified phenolic resin and its degradation residues were characterized by X-ray diffraction . Every sample was scanned from a 2θ angle of 10–70 ° at a scan rate of 5 °/min. Under the same conditions, neat phenolic resin was also investigated by the above characterizations.The chemical modification of phenolic resin by POSS was investigated by Fourier transform infrared spectroscopy, on KBr pellets from 400 cm−1 and 1096 cm−1. The absorption peak at 1703 cm−1is assigned to C=O in the maleimide group of POSS-8Phenol, and the characteristic of Si–O–Si stretching is at 1096 cm−1, these being consistent with the literature [2OH are at around 3500 cm−1 (broad peak); the C–H stretching vibration absorption peaks in –CH2– range from 2800 cm−1 to 2950 cm−1; the stretching vibration peaks of the C=C double bond in the benzene ring appear at 1610 cm−1 and 1510 cm−1; the characteristic absorption peak of C–O in the phenolic group is at 1270 cm−1; the absorption peaks of the aliphatic C–O stretching vibration are at 1130 cm−1 and 1005 cm−1; and the ortho- and para-substituted peaks of the benzene ring are at 760 cm−1 and 870 cm−1. All these absorption peaks are also reported in the synthesis results of phenolic resin elsewhere [The IR spectra of neat phenolic resin and modified phenolic resin are shown in terature . Other iThermogravimetric analysis is widely used to determine the thermal stability of polymer materials. The advantage is that the relationship between the mass loss percentage and the temperature can be observed from the obtained curve, and the thermal stability of the material can be more intuitively evaluated . Figure The thermogravimetric curves of neat phenolic resin under argon and air atmosphere are shown in The thermogravimetric curves of POSS modified phenolic resin under argon and air atmosphere are shown in Many studies on the thermal degradation of phenolic resin under inert gas atmosphere could be found elsewhere ,30,31,32Different from the thermal degradation result under argon, the residual char yield of the modified phenolic resin is significantly increased with the elevation of the depth of thermal degradation under air. As shown in m/z of 2, 16, 18, 28, 30, 44 and 94 are assigned to hydrogen, methane, water, carbon monoxide, ethane, carbon dioxide and phenol, respectively.In order to understand the thermal degradation mechanism of phenolic resin, the gas produced by pyrolysis is further investigated under argon and air atmosphere at elevated temperatures. Mass spectrometry is used to detect small molecular volatiles during the thermal degradation process of neat phenolic resin and POSS modified phenolic resin. The results of the TG-MS study under argon and air are presented in As shown in 2–) groups. Trick et al. pointed out that the methylene groups are easily attacked and broken during the thermal degradation process of phenolic resin [The main chain of phenolic resin is connected by methylene  are observed in the degradation residues. The presence of SiO2 is mainly attributed to the reaction between POSS and oxygen at high temperatures. Hence, POSS has an oxidation–reduction effect on the thermal degradation process of phenolic resin, resulting in the improvement of its thermal stability under air atmosphere.After thermal degradation under air, the degradation residues of neat phenolic resin still show the characteristic peaks of char in their XRD pattern. However, as shown in the XRD pattern of POSS modified phenolic resin, besides the characteristic peaks of char, the characteristic peaks of SiOA POSS modified phenolic resin is synthesized as a matrix of thermal protection material to enhance its thermal stability. The thermal stability and the thermal degradation products of POSS modified phenolic resin are investigated by TGA, TG-MS and XRD. Neat phenolic resin is also fabricated to compare the structure and performance with POSS modified phenolic resin over the whole process of study. The major conclusions are presented below.The introduction of POSS makes phenolic resin show better thermal stability under air. The residual char yield of POSS modified phenolic resin at 800 °C is 14.73% higher than that of phenolic resin. However, under argon atmosphere, the residual char yield of POSS modified phenolic resin at 800 °C is only 6.95% higher than that of phenolic resin.Under argon, phenolic resin releases the degradation volatiles at around 580–610 °C, while POSS modified phenolic resin does not reach the maximum speed until 630 °C. The corresponding volatiles evolutions under air are more complex than those under argon. Under air, the volatiles release rate of phenolic resin is the fastest at around 480–520 °C, while volatiles produced by the thermal degradation of POSS modified phenolic resin reach the maximum peaks at 540–610 °C.2 is detected in the residue of POSS modified phenolic resin after degradation under air. The existence of SiO2 is mainly attributed to the reaction of POSS with oxygen at high temperatures, and the existence of SiO2 can effectively improve the high temperature oxidation resistance of phenolic resin.The degradation processes of both phenolic resins are carbonization processes, and the solid phase in the residual products is mainly composed of char. In addition to the char, crystalline SiO


The wastewater from ready-mixed concrete plants is currently being recycled as concrete mixing water. It has attracted significant attention from the construction industry and researchers since it promotes sustainable development through environmental protection, energy-saving, and emissions reduction. This article review first introduces the nature of wastewater in ready-mixed concrete plants in different regions. Then the effects of solid content in water on various properties of concrete, including working performance, durability and microscopic properties, are reviewed, respectively, when concrete is mixed with wastewater instead of tap water. Furthermore, the microscopic mechanism of action in concrete mixing with wastewater is discussed, and future work is recommended. This review provides fundamentals on the study of the properties of concrete after wastewater is mixed into concrete. Persistently increasing demand for concrete and the advocacy of environmental protection, energy-saving, and greenhouse emissions reduction through waste concrete recycling has gained significant attention worldwide. Bu et al.  used recCurrently, regarding the use of wastewater from the ready-mix concrete plant as concrete mixing water, the concentration and dosage of wastewater are considered the main influencing factors. The change in the concentration and dosage of wastewater may be attributed to the change in total solid content in mixing water , and totIn order to save energy consumption, protect the environment and improve the level of comprehensive utilization of resources, the wastewater and slurry recycling system is established in the concrete ready-mix plant, and its main process flow chart is shown in In different ready-mix concrete plants, the solid content of wastewater and the types of additives are different. The wastewater contains a large number of residual cement particles , which lChatveera et al.  magnifie2, SiO2, CaCO3, AFt, unhydrated C2S, C3S, and CaSO4•2H2O. The structure of fresh wastewater particles is relatively loose with a small particle size 18] is moAs is shown in The alkaline environment provided by wastewater is conducive to the hydration reaction of cement. At the same time, the filling and bonding of wastewater particles enhance the compactness of concrete and promote the improvement of compressive strength of concrete. When the tap water is replaced by wastewater too much, the alkalinity of the concrete matrix increases. As a result, the cohesion of the transition zone between cement paste and aggregate is weakened, and the compressive strength of concrete is reduced ,27. In aThe mechanical properties of concrete are closely related to the curing age of concrete. Generally, with the extension of the curing age, the mechanical indexes of various mechanical properties will increase accordingly. In order to fully understand the characteristics of the later strength growth of concrete mixed with waste water replacing tap water in a certain proportion, scholars have also studied its compressive strength under long-term conditions. Li  found thAccording to the research results of different scholars, the ratios of the 28-day compressive strength of concrete mixed with water with different solid contents and concrete mixed with tap water were calculated, as shown in In summary, domestic scholars (in China) have shown that the compressive strength of wastewater concrete is 95–115% of ordinary concrete, while the results of foreign researchers are generally lower than domestic ones, most of which are 85–100%. This may be caused by different wastewater treatment technologies, additives and mineral admixtures (such as fly ash and silica fume) at home and abroad.The durability of concrete has long been a concern for people, and various substances contained in wastewater will also have an influence on concrete durability.Most researchers used the electric flux method to study the anti-chloride ion permeability of concrete. Under the condition of the same strength grade of concrete, the chloride ion penetration resistance of concrete becomes stronger with the increase of the solid content  as the f2 in the air from interacting with the hydration products of the cement stone in the concrete, thereby improving the carbonization resistance of the concrete, protecting the steel bars from corrosion, and improving the concrete structure.Researchers studied the effect of mixed water with different solid content on the anti-carbonization performance of different strength grades of concrete. As the solid content in the mixing water increases, the carbonation depth of concrete with different strength grades decreases ,30, whicFreeze-thaw cycle is the main environmental factor affecting the durability of concrete, and the mixing of wastewater has a certain influence on the frost resistance of concrete. Qu  used theTherefore, it can be concluded that the ready-mixed concrete plant wastewater can enhance the frost resistance of concrete. With the increase in the higher solid content in mixing water, it is more helpful to improve the frost resistance of concrete.Sulfate corrosion resistance of concrete is also a very important part of concrete durability research. Chatveera et al.  studied In summary, there are few studies on the impact of the use of ready-mixed concrete plant wastewater as mixing water on concrete durability at present, especially the frost resistance and sulfate resistance of concrete. However, from the research status, the solid content of mixed water increases, which promotes the improvement of concrete compactness and is beneficial to the improvement of chloride ion penetration resistance, carbonation resistance, frost resistance and sulfate erosion resistance of concrete. There are great differences in the research results of durability between domestic and foreign researchers, which may be caused by the differences in wastewater treatment technology, additive types and mineral admixtures when preparing concrete. Compared with foreign research, domestic researchers generally add fly ash and mineral powder to concrete. It carries out secondary hydration in the concrete, which weakens the adverse effect of the addition of wastewater on the concrete, thereby improving the durability of the concrete .2 in tap water and waste water mixed cement paste tested by XRD is similar at 7 days, and the content of Ca(OH)2 in tap water mixed cement paste at 28th day is slightly lower than the peak value of Ca(OH)2 in waste water mixed cement paste. Li [The concentration of wastewater, dosage, standing time, and types of additives will all have an impact on the microstructure of concrete. He et al.  mixed C8aste. Li  analyzedaste. Li  mixed ceIn summary, only a few researchers have studied the changes of microstructure and properties of concrete mixed with wastewater in previous studies. The mixed wastewater will change the material composition and its content of concrete and, at the same time, also affect the microstructure of concrete. Macro-mechanical properties are the manifestation of microstructure, and the changing trend of macro-mechanical properties can be accurately grasped only by clarifying the micro-mechanism of wastewater concrete performance change. Therefore, it is essential to study the micro-structure of wastewater concrete, and analyze its mechanism through its micro-means to provide the basis for the research of macro-performance change of concrete.A comprehensive literature review is presented herein on the performance of wastewater concrete. First, the properties of wastewater from a ready-mixed concrete plant are introduced. Then a great number of test results from different studies are collected, and focusing on comparing the influence of the solid content of wastewater on the work performances, mechanical properties, durability and microstructures of concrete. Finally, some suggestions are put forward for future work.(1)The main components of wastewater in different regions are roughly the same, i.e., main cement hydration products and fine sands and gravel particles, however the solid content of wastewater is quite different. Therefore, if wastewater is recycled, the solid content of wastewater from the ready-mixed concrete plant should be detected simultaneously, and the solid content of wastewater should be adjusted as needed before use.(2)Concrete is prepared by replacing tap water with wastewater in a certain proportion. When the solid content of the mixed water is less than or equal to 6%, the change of concrete slump is within 30 mm. When the solid content in the mixed water is at the optimal solid content, the fluidity and compressive strength of the concrete change little compared to the concrete prepared from tap water, and the optimal solid content in the mixed water of wastewater is generally less than or equal to 5%.(3)The filling effect of wastewater particles can enhance the concrete durability to a certain extent. Currently, there are a few studies on the frost resistance and sulfate corrosion resistance of wastewater concrete. The influence of the solid content of wastewater on the frost resistance and sulfate resistance of concrete with different water-binder ratios is unclear, and as such, research on these aspects should be strengthened.(4)The storage time of wastewater greatly influences on the properties of wastewater particles, which leads to different effects of wastewater on various concrete properties. At present, there are limited studies on the influence of wastewater storage time on various properties of concrete. Further research should be carried out on the influence of wastewater storage time on concrete.(5)At present, there are few researches on the influence of wastewater on the microstructure of concrete. However, the changes of macroscopic mechanical properties of concrete are the external manifestation of the changes of microstructure. Therefore, we should strengthen the research in this area to provide reference for evaluating the changes of macroscopic mechanical properties of concrete.