Entry Path Research Articles

Measures to Reduce the Discharge of tire Wear into the Environment

The environmental impact of tire wear emissions has become increasingly apparent, and efforts to reduce their impact on the environment are on the rise. To minimise the generation of tire wear, it is essential to consider the influencing factors. However, as it cannot be entirely prevented, measures to reduce immissions are also necessary. This paper summarises possible measures derived from the literature, stakeholder workshops, and the authors’ own conclusions, taking into account the different perspectives: tire, vehicle, road, sustainable mobility and emissions treatment. The presentation of the entry paths of tire wear into the environment and the hotspots of generation can be used to prioritise reduction measures. Measures should be implemented at a political level, technical solutions applied, and awareness raised among the general public. It is evident that reducing tire wear is a complex task that requires a transdisciplinary approach.

Design of Path-Planning System for Interventional Thermal Ablation of Liver Tumors Based on CT Images.

Aiming at the shortcomings of artificial surgical path planning for the thermal ablation of liver tumors, such as the time-consuming and labor-consuming process, and relying heavily on doctors' puncture experience, an automatic path-planning system for thermal ablation of liver tumors based on CT images is designed and implemented. The system mainly includes three modules: image segmentation and three-dimensional reconstruction, automatic surgical path planning, and image information management. Through organ segmentation and three- dimensional reconstruction based on CT images, the personalized abdominal spatial anatomical structure of patients is obtained, which is convenient for surgical path planning. The weighted summation method based on clinical constraints and the concept of Pareto optimality are used to solve the multi-objective optimization problem, screen the optimal needle entry path, and realize the automatic planning of the thermal ablation path. The image information database was established to store the information related to the surgical path. In the discussion with clinicians, more than 78% of the paths generated by the planning system were considered to be effective, and the efficiency of system path planning is higher than doctors' planning efficiency. After improvement, the system can be used for the planning of the thermal ablation path of a liver tumor and has certain clinical application value.

Micro-robotic percutaneous targeting of type II endoleaks in the angio-suite

PurposeEndovascular aneurysm repair has emerged as the standard therapy for abdominal aortic aneurysms. In 9–30% of cases, retrograde filling of the aneurysm sac through patent branch arteries may result in persistence of blood flow outside the graft and within the aneurysm sac. This condition is called an endoleak type II, which may be treated by catheter-based embolization in case of continued sac enlargement. If an endovascular access is not possible, percutaneous targeting of the perfused nidus remains the only option. However, this can be very challenging due to the difficult access and deep puncture with risk of organ perforation and bleeding. Innovative targeting techniques such as robotics may provide a promising option for safe and successful targeting.MethodsIn nine consecutive patients, percutaneous embolization of type II endoleaks was performed using a table-mounted micro-robotic targeting platform. The needle path from the skin entry to the perfused nidus was planned based on the C-arm CT image data in the angio-suite. Entry point and path angle were aligned using the joystick-operated micro-robotic system under fluoroscopic control, and the coaxial needle was introduced until the target point within the perfused nidus was reached.ResultsAll punctures were successful, and there were no puncture-related complications. The pre-operative C-arm CT was executed in 11–15 s, and pathway planning required 2–3 min. The robotic setup and sterile draping were performed in 1–2 min, and the alignment to the surgical plan took no longer than 30 s.ConclusionDue to the small size, the micro-robotic platform seamlessly integrated into the routine clinical workflow in the angio-suite. It offered significant benefits to the planning and safe execution of double-angulated deeply localized targets, such as type II endoleaks.

A Comparative Study of Students Graduation Analysis Using Classification Methods in Undergraduate Electrical Engineering Tidar University

This research aimed to classify achievement factors for electrical engineering students at Tidar University using K-Means and Agglomerative Clustering classification algorithms. The goal was to understand if any parameters influence high-achieving student performance. The Indonesian government and private sector for university students provide significant education funds. Student scholarships are awarded based primarily on GPA and entry path, overburdening staff and causing confusion during distribution to eligible recipients. A system was needed to accommodate additional eligible criteria. The researcher selected factors to identify engineering student performance, including school origin, entry path, tuition fees, and GPA. These inputs could determine graduation status. The results compared calculation methods based on collected data accuracy, processing times, and characterizing clustered data to determine the best classification method. Agglomerative Hierarchical Clustering performed better. Accuracy testing on 600 training data points yielded 73.94% for improved K-means and 90.42% for AHC. The Average processing time was 674.92 seconds for improved K-means and 554.35 seconds for AHC. Silhouette testing also characterized calculation methods, with improved K-means scoring best at 0.654 and AHC at 0.787 using two clusters.

Numerical Study of Plasma Characteristics Under Magnetohydrodynamic Flow Control in Mars Entry

Magnetohydrodynamic flow control is an active thermal protection method for atmospheric entry vehicles. This study examined the plasma characteristics under magnetohydrodynamic flow control and its thermal protection ability at multiple altitudes (20–60 km) on a typical direct Mars entry path using numerical simulation considering the Hall effect. The simulation considered a spherical-conical capsule with an entry velocity of 8 km/s at an altitude of 60 km, equipped with a dipole magnet generating a magnetic field of approximately 0.3 T at the stagnation point of the capsule. The results showed that magnetohydrodynamic flow control can mitigate convective aerodynamic heating at high altitudes (45 km or more), where the high electrical conductivity of the plasma creates strong magnetohydrodynamic interaction. In contrast, at low altitudes (35 km or less), magnetohydrodynamic flow control is ineffective owing to low electrical conductivity. The high electrical conductivity at high altitudes is attributed not only to large flight velocities under low atmospheric pressures but also to the enlargement of the shock layer owing to the strong magnetohydrodynamic interaction, which expands the ionization progression area. Furthermore, the results indicated that considering the Hall effect in the numerical modeling of magnetohydrodynamic flow control in Mars direct entry is essential.

A framework for investigating new firm entry: The (limited) overlap between informal-formal and necessity-opportunity entrepreneurship

We analyse entrepreneurial entry along the dimensions of informal-formal and necessity-opportunity entrepreneurship, distinguishing between them yet considering them jointly. While the dominant view in the literature conflates necessity with informal entry, and opportunity with formal entry, we hypothesise that informal entrepreneurship may be attractive to higher-income individuals as a testing ground for entrepreneurial ideas. We also explain why higher-income individuals may undertake necessity entrepreneurship. We utilise individual Global Entrepreneurship Monitor (GEM) data from Chile (2019–2021), which identifies informal-formal and necessity-opportunity entrepreneurial entry modes, to test hypotheses on the role of individuals´ income in the four types of entrepreneurial entry. We also consider changes in entrepreneurial entry during a crisis and a non-crisis periods. Our results confirm that the patterns in the data are consistent with hypotheses derived from our proposed theoretical framework. Executive summaryEmerging markets economies have very large informal sectors, and their entrepreneurial entry is often motivated by economic necessity rather than by business opportunity. But neither informal nor necessity entrepreneurship are usually expected to generate the positive benefits for growth and development predicted for formal and opportunity entrepreneurship. We argue that the dominant stream in the literature actually conflates informal and necessity entrepreneurship, both of which have been associated with low human and financial capital and productivity. We propose that the appropriate typology is more complex than this because there are examples of successful and dynamic informal firms. This leads us to identify four categories of entrepreneurial entry: informal-necessity (Type 1), formal-opportunity (Type 2), informal-opportunity (Type 3), and formal-necessity (Type 4). While necessity entrepreneurship has typically been associated with low-income individuals, we propose that formal-necessity entrepreneurship may be an entry path for both low- and high-income individuals, though for different reasons. Informal opportunity entry may likewise be an option for people with low-income as well as high-income.We therefore seek to disentangle the analysis of opportunity-necessity and of formal-informal entry and to demonstrate that the two less explored entry modes - informal-opportunity, and formal-necessity - are of considerable theoretical and practical significance in emerging economies. We test our framework in the emerging market economy setting of Chile, one of the more prosperous and open economies in Latin America. We use Global Entrepreneurship Monitor (GEM) data which uniquely for Chile allow us to distinguish between individuals along both the formal-informal and the necessity-opportunity dimensions. On this basis, we distinguish empirically between these four categories of entrepreneurial entry and explain how higher-income individuals may use informal-opportunity entrepreneurial entry as a “seed bed” to test their new business ideas. At the same time, we show that necessity entrepreneurship may be attractive to both lower- and higher-income individuals.We also show that the interplay between individuals´ income groups and four entrepreneurial entry modes is stable over “normal times” versus “crisis periods”. We observe that in response to a crisis, individuals with lower-incomes are likely to engage more in informal-necessity entrepreneurship while opportunity-informal entry by higher-income individuals will decline. These changes represent a more complex adjustment pattern than has been identified for developed economies, where entrepreneurial activity has been found to be countercyclical. Thus, in emerging markets, informal-necessity entrepreneurship plays a stabilizing role for those individuals with a more marginal position in the labor market during the crisis. In contrast, for those individuals who have access to higher household income, all forms of entrepreneurship become a less attractive option. We interpret this as indicating that these individuals have the option to wait for higher return opportunities to re-emerge. This is one of the first papers to explore the impact of the COVID-19 pandemic on entrepreneurship in an emerging market economy.

Path and control-constrained longitudinal guidance for Mars entry

This paper proposes a novel longitudinal reference trajectory tracking guidance framework for Mars atmospheric entry. Unlike traditional methods that require strict adherence to pre-defined safe trajectories, this guidance framework incorporates path constraints into the closed-loop tracking process to ensure safety. The framework comprises a safety module and a guidance law module. The safety module employs an online path constraints management algorithm that converts real-time path constraints into equivalent control constraints and applies them to the guidance module. The guidance law module uses the anti-saturation generalized super-twisting based sliding mode (ASGSTSM) guidance law, which provides sufficient rapidity and robustness to achieve trajectory tracking while accounting for uncertainties and control saturation. Simulation results demonstrate that the proposed guidance framework effectively ensures compliance of the entry vehicle with path constraints. The ASGSTSM guidance law exhibits notable speed and robustness, making it adaptable within the guidance framework. Particularly, in Monte Carlo simulations introducing significant uncertainty, incorporating the ASGSTSM guidance law within the guidance framework resulted in convergence in all trajectory tracking processes, whereas guidance laws in the control group led to numerous failures. Additionally, the paper offers practical principles for designing guidance laws within this universal framework. This facilitates future research to easily replace the guidance law module based on specific mission requirements.

APPLICATION OF BAGGING CART IN THE CLASSIFICATION OF ON-TIME GRADUATION OF STUDENTS IN THE STATISTICS STUDY PROGRAM OF TANJUNGPURA UNIVERSITY

The timeliness of graduation is used as the success of students in pursuing education which can be seen from the time taken and measured by the predicate of graduation obtained. The characteristics of students who tend to graduate not or on time can be analyzed using classification techniques. Classification and Regression Tree (CART) is one of the classification tree methods. There is a weakness in CART, which is less stable in predicting a single classification tree. The weaknesses in CART can be improved by using Ensemble methods, one of which is Bootstrap Aggregating (Bagging) which can reduce classification errors and increase accuracy in a single classification model. This study aims to classify and determine the accuracy of Bagging CART in the case of the accuracy of student graduation classification. The number of samples used is 140 data on the graduation status of Untan Statistics Study Program students from Period I of the 2017/2018 academic year to Period II of the 2022/2023 academic year. The variables used are the timeliness of graduation which is categorized into two namely Not and On Time, Gender, Semester 1 GPA, Semester 2 GPA, Semester 3 GPA, Semester 4 GPA, Region of Origin Domicile, High School Accreditation, Entry Path, Scholarship, and first TUTEP. A good classification can be seen from the accuracy value. The CART method obtained an accuracy value of 70%. While using the CART Bagging method obtained an accuracy value of 85.71%. Based on the accuracy value obtained, the application of the CART Bagging method can increase accuracy and correct classification errors on a single CART classification tree by 15.71% by resampling 25 times.

Early enterovirus translation deficits extend viral RNA replication and elicit sustained MDA5-directed innate signaling.

Multiple pattern recognition receptors sense vRNAs and initiate downstream innate signaling: endosomal Toll-like receptors (TLRs) 3, 7, and 8 and cytoplasmic RIG-I-like receptors (RLRs) RIG-I, and MDA5. They engage distinct signaling scaffolds: mitochondrial antiviral signaling protein (RLR), MyD88, and TLR-adaptor interacting with SLC15A4 on the lysosome (TLR7 and TLR8) and toll/IL-1R domain-containing adaptor inducing IFN (TLR3). By virtue of their unusual vRNA structure and direct host cell entry path, the innate response to EVs uniquely is orchestrated by MDA5. We reported that PVSRIPO's profound attenuation and loss of cytopathogenicity triggers MDA5-directed polar TBK1-IRF3 signaling that generates priming of polyfunctional antitumor CD8+ T-cell responses and durable antitumor surveillance in vivo. Here we unraveled EV-host relations that control suppression of host type-I IFN responses and show that PVSRIPO's deficient immediate host eIF4G cleavage generates unopposed MDA5-directed downstream signaling cascades resulting in sustained type-I IFN release.

Expression of key SARS-CoV-2 entry molecules in surgically obtained human retinal biopsies.

To investigate the presence of ACE2, TMPRSS2 and Furin, i.e., a key player in the ocular infection with SARS-COV-2, in surgically obtained human retinal tissue samples from SARS-CoV-2-negative patients, using gene expression analysis. The mechanisms and entry paths of ocular infections have been ill-defined so far. To better understand the possible entry routes, we used surgically explanted retinal tissue from nine patients that were not infected with SARS-CoV-2 and analyzed the message expression of the three key molecules that confer viral entry into cells using polymerase chain reaction. The median age of the patients (n = 9) included in the study was 52years (IQR 48, 55). Eight patients underwent surgery for rhegmatogenous retinal detachment and one patient for tractional retinal detachment. Gene expression for the proteins studied was detected in all nine patients. The results of analysis by Livak's method (2001) demonstrated a median TMPRSS2 gene expression value of 20.9 (IQR 11.7, 33.7), a median ACE2 gene expression value of 2.09 (IQR 1.14, 2.79) and a median Furin gene expression value of 8.33 (IQR 5.90, 11.8). In conclusion, TMPRSS2, Furin and ACE2 are expressed in the retina and may contribute to the retinal involvement in COVID-19 patients. Expression may vary among individuals, which may explain why some patients may be more prone to retinal involvement during SARS-CoV-2 infection COVID-19 patients than others. Variability in the expression of TMPRSS2, Furin and ACE2 proteins themselves may also explain the presence or development of retinal symptoms of varying severity.

Optimizing Hospital Waste Management through Fly Trap Technology: A Cost and Potential Problem Analysis

The problem that often occurs in hospitals is that regulations related to hospital environmental health still need to be popular in the community. However, the development of technology and science has made agricultural tools and machines experience development and renewal and adapt to environmental conditions. Many types of fly control are available, such as fly traps in temporary garbage shelters in hospitals. This study analyzes operational needs and problems encountered by implementing fly trap technology in hospitals. This study consisted of three stages: budgeting, calculating the Kepner-Tregoe Situation Appraisal (KTSA), and the Kepner-Tregoe Potential Problem Analysis (KTPPA). The total operational costs required for this tool are IDR 887,496.00. Where this cost includes the component of preventing problems that must be faced in fly trap operations. Identification of tool constraints in operation consists of damage to the net on the fly trap, garbage piling up due to overloading in the garbage container, blockage of the entry path for flies to the fly trap, and the garbage collector coming into contact with the waste at the TPS. There are four potential problems in implementing fly traps that we previously identified, where there are possible causes, preventive actions, and contingent actions that can be taken to overcome these potential problems.

Zonation system in admission of new student at state secondary school in Indonesia: how predictable to learning success

Introduction. A new student acceptance model with the zoning system raises various problems, including the unequal number of public schools in an area causing students to experience barriers to obtaining a proper education. The decrease in motivation and achievement of students is because the selection is only based on zoning, and the achievements of prospective students at the previous education level are not considered. Students fail to enter superior schools because they are outside the zone. The distribution of quality public schools are not evenly distributed, causing limited choices and causing the implementation of the principle of justice in access to education services – lack of readiness of local governments in setting zones.Aim. From the problems above, this study aims to find differences in learning achievement in terms of admission, predict learning achievement from elementary school to junior high school, and determine graduation document predictions with a zoning system on student achievement.Research methodology and methods. The research used a quantitative approach from October 2021 to March 2022. The research sample was 356 students who entered the 2018 state junior high school and graduated from the 2020 school year junior high school. The sampling technique for this study used proportional random sampling. Determining the size of the research sample was done by considering the pathways for accepting new students: the zoning path, the achievement path, the affirmation path, and the parent transfer path. Data analysis used ANOVA and multiple regression analysis at a significance level of 5%.Results and scientific novelty. The results showed no difference in the average report cards of junior high school students when viewed from the path when they entered the junior high school through the zoning system. The results of one-way ANOVA obtained F = 1.298 with a significance level of 0.275. The differences in the entry paths of students to junior high school, namely from the zoning pathway, academic and non-academic achievement pathways, affirmation pathways, and parental transfer paths, are proven not to affect their learning achievement in junior high schools. There is a linear regression from students’ learning achievement in elementary school to students’ learning achievement in junior high school. The partial and simultaneous tests show that it is not proven that learning achievement in elementary school affects learning achievement in junior high school. When they graduate from elementary school, students’ learning achievement has a weak predictive power on students’ learning achievement in junior high school. The national primary school-based school examination average, elementary school report card average, and elementary school examination average, used as entry requirements to junior high school in the zoning system, only have a predictive power of 1.4–2,7%.Practical significance. Parents can use this research to make decisions on their child’s education. Parents do not need to worry about the zoning system implemented by the government in accepting new students because the zoning system does not affect children’s achievements at the level of education they take. The school must also implement education systems and policies properly so that the quality of education in each institution is maintained so that parents do not worry about choosing a place for their child’s education.

Issues of organizing vessels pilotage through the drawbridges spans in St. Petersburg

The topic of the work is an overview study of the current problem associated with the complexity of navigation of river vessels and river-sea-going vessels during their passage along the Neva River in the raised spans of St. Petersburg bridges. It is noted that when passing through the raised spans of St. Petersburg bridges in the induced state, such factor as the “surface dimension” is one of the main ones. It is emphasized that large-tonnage river and river-sea-going vessels cannot pass all the bridges of St. Petersburg when they are in the induced state, but since the bridges are drawn at night during navigation period, the height restriction is no longer so strict. Unfortunately, all bridges of St. Petersburg have only one draw span, so reverse navigation is organized through their raised spans in order, firstly, to avoid divergences of vessels in the sections between the bridges and, secondly, to enable the skipper to minimize manoeuvring when choosing the optimal path of entry into the raised span of the bridge. In addition, the attention is drawn to the fact that when entering the drawbridge span, the skipper must take into account many additional factors, including, for example, local navigation features, the actual hydro-meteorological situation and the current hydrological regime of the Neva River. It is noted in the study that the boatmaster should take into account such an important circumstance as the presence of a large number of pleasure craft used for sightseeing viewing of the process of vessel movement through the raised spans of bridges. Due to the fact that boatmasters of large-tonnage river vessels and river-sea-going vessels may experience significant difficulties in the process of organizing navigation safety when moving into the raised bridge spans on the Neva River section within the boundaries of St. Petersburg; mandatory pilotage, some features of the organization of which are considered in this work, has been established. Examples of accidents related to the procedure of bridges drawing that occurred within the boundaries of St. Petersburg and had serious consequences are analyzed. The amendments proposed to be made to the “Rules of movement and mooring of vessels in the Volga-Baltic basin of the inland waterways of the Russian Federation” in relation to the issue under consideration are considered.

The Ancestral Shape of the Access Proton Path of Mitochondrial ATP Synthases Revealed by a Split Subunit-a.

The passage of protons across membranes through F1Fo-ATP synthases spins their rotors and drives the synthesis of ATP. While the principle of torque generation by proton transfer is known, the mechanisms and routes of proton access and release and their evolution are not fully understood. Here, we show that the entry site and path of protons in the lumenal half channel of mitochondrial ATP synthases are largely defined by a short N-terminal α-helix of subunit-a. In Trypanosoma brucei and other Euglenozoa, the α-helix is part of another polypeptide chain that is a product of subunit-a gene fragmentation. This α-helix and other elements forming the proton pathway are widely conserved across eukaryotes and in Alphaproteobacteria, the closest extant relatives of mitochondria, but not in other bacteria. The α-helix blocks one of two proton routes found in Escherichia coli, resulting in a single proton entry site in mitochondrial and alphaproteobacterial ATP synthases. Thus, the shape of the access half channel predates eukaryotes and originated in the lineage from which mitochondria evolved by endosymbiosis.

Motivation to teach and preparedness for teaching among preservice teachers in China: The effect of conscientiousness and constructivist teaching beliefs.

"Preparedness for teaching" refers to the degree of confidence preservice teachers have, and reflects their ability. Developing preparedness for teaching is an important part of preservice teachers' professionalization. A substantial body of literature has documented the critical influence of the motivation to teach on preparedness; however, how this relation is impacted by mediating and moderating mechanisms remains unclear. To respond to this gap in knowledge, the present study constructed a mediated moderation model through structural equation modeling and multigroup tests using 383 questionnaires completed by preservice teachers in China. The findings indicate that the preservice teachers' genders, entry path, and levels of certainty about their future teaching career choices all influence their preparedness for teaching. Specifically, preservice teachers who believe that they will choose a teaching career in the future have more intrinsic motivation, stronger constructivist teaching beliefs, and a higher levels of teaching preparedness. Moreover, preservice teachers' motivations to teach can positively predict their constructivist teaching beliefs and preparedness for teaching, but their constructivist teaching beliefs alone do not have a mediating effect on the relationship between motivation to teach and preparedness for teaching. However, the findings reveal that the constructivist teaching beliefs of highly conscientiousness group can partially mediate the relationship between the motivation to teach and the preparedness for teaching. Additionally, conscientiousness moderates the influence of constructivist teaching beliefs on preparedness for teaching. The study provides meaningful insights into the within-personal traits of how and when motivation to teach affects preparedness for teaching, which may be useful for the motivation best practices for preservice teacher recruitment, training, and support to create high-quality teachers.

Study of multiple solution phenomenon for hypersonic air inlet

From current study the flow states of hypersonic inlet are classified into two types: start and unstart. Between start and unstart exists the double solution region, which forms the classical double solution theory of air inlet. However, because the shock in hypersonic inlet strongly interferes and interconnects with the boundary layer, it is very hard for the classical double solution theory to explain all flow phenomena. Profound study was done to improve understanding of hypersonic inlet and 4 distinct types of flow mode which disrelated with overrating were discovered from experiments, supplemented with CFD calculations. They are flow mode of start, large separation on body (LSB), small separation on body (SSB), and dual-separation on both body and lip (DSBL). The study also found that there is hysteresis phenomenon between the four types of flow mode and that their pairwise combinations produce six types of double solution region. Furthermore, according to the historical status and different entry paths, the study found out three types of triple solution region: “start + LSB + DSBL”, “LSB + SSB + DSBL”, and “start + SSB + DSBL”. The study results not only greatly enrich the theory of hypersonic inlet, but also have great significance in guiding engineering practice of air inlet.

Role of Insect and Mammal Glutathione Transferases in Chemoperception.

Glutathione transferases (GSTs) are ubiquitous key enzymes with different activities as transferases or isomerases. As key detoxifying enzymes, GSTs are expressed in the chemosensory organs. They fulfill an essential protective role because the chemosensory organs are located in the main entry paths of exogenous compounds within the body. In addition to this protective function, they modulate the perception process by metabolizing exogenous molecules, including tastants and odorants. Chemosensory detection involves the interaction of chemosensory molecules with receptors. GST contributes to signal termination by metabolizing these molecules. By reducing the concentration of chemosensory molecules before receptor binding, GST modulates receptor activation and, therefore, the perception of these molecules. The balance of chemoperception by GSTs has been shown in insects as well as in mammals, although their chemosensory systems are not evolutionarily connected. This review will provide knowledge supporting the involvement of GSTs in chemoperception, describing their localization in these systems as well as their enzymatic capacity toward odorants, sapid molecules, and pheromones in insects and mammals. Their different roles in chemosensory organs will be discussed in light of the evolutionary advantage of the coupling of the detoxification system and chemosensory system through GSTs.

Widespread occurrence of quaternary alkylammonium disinfectants in soils of Hesse, Germany.

Quaternary alkylammonium compounds (QAACs) are cationic organic compounds with amphiphilic properties that are widely used as surfactants and disinfectants in industry, households and agriculture. Several studies suggest that QAACs co-select for antibiotic resistant microorganisms and thus may contribute to the spread of antibiotic resistance in the environment. Data on QAAC occurrence in soil are scarce and limited to soils that are prone to direct exposure to QAACs. Therefore, we conducted a comprehensive study on the occurrence of QAACs in soils of Hesse, a federal state in Germany, covering an area of 21,115 km2. Sixty-five soil samples that comprised different land uses (arable, grassland, forest, vineyard) and area types (rural, agglomeration) were analysed for concentrations of alkyltrimethylammonium (ATMACs, with alkyl chain lengths C8-C16), benzylalkyldimethylammonium (BACs, C8-C18) and dialkyldimethylammonium compounds (DADMACs, C8-C18) via HPLC-MS/MS after ultrasonic-assisted extraction with acidified acetonitrile. QAACs were detected in 97 % of the soil samples irrespective of land use and area type. The most abundant QAAC homologues were DADMACs > BACs > ATMACs. The highest total QAAC concentrations were detected in alluvial soils influenced by the deposition of suspended particles during flood events, with DADMAC-C16 and -C18 as the dominant homologues. The high abundance of long-chain DADMACs suggests that legacy pollution and accumulation govern QAAC concentrations in soils. The presence of QAACs in forest soils points to a potential input via atmospheric deposition. Our work highlights the widespread occurrence of QAACs in soils of Hesse and the need for more research on their entry paths and fate in the soil ecosystem.

Performance of Bacillus Cohnii Added Microbial Concrete

In the era of rapid urbanization, concrete has been playing a very important role in construction industry but inherently, it is very much vulnerable to formation of cracks, due to which its durability gets decreased. If immediate action is not taken, cracks developed in the section may spread further and increase the cost of repair. In concrete structures, these cracks become an easy path of entry for water, oxygen and carbon dioxide resulting into the decrease in durability of concrete. Numerous researches around the world are on to heal this defect with the help of addition of various bacteria in the form of Bacterial Concrete. This study aims to find out the change in salient properties of concrete experimentally after adding the microbes. Concrete cubes were cast with different bacteria concentrations, tested for salient properties after 7 and 28 days. Test results reveal that addition of bacteria results into increase in compressive strength and decrease in water absorption and porosity of concrete. Findings also indicate that the concrete mix with higher bacteria concentration gives higher compressive strength and lower water absorption and porosity in concrete.

971. Antibiotic Prophylaxis for Grade III Open Fractures: A Retrospective Comparison of Ceftriaxone plus Vancomycin versus Cefazolin plus Gentamicin

Abstract Background Owing to the established path of bacterial entry and contamination-associated mechanisms, grade III open orthopedic fractures represent a substantial infection risk. Historically, the EAST Guidelines recommended covering Staphylococcus aureus and adding aminoglycoside gram negative coverage. Incorporating newer evidence, the Allegheny Health Network local guidelines rely on ceftriaxone to cover gram-negatives and add methicillin-resistant S. aureus coverage with vancomycin. Methods The electronic health records of adults admitted for a grade III open fracture between January 1, 2016, and October 31, 2021 were retrospectively reviewed. Patients who received cefazolin and gentamicin (CZ+GM) or ceftriaxone and vancomycin (CRO+VA) as their prophylaxis were included. We recorded rate of a composite treatment failure outcome of receipt of antibiotics for suspected infection, infection-related hospitalization, or subsequent debridement for injury site skin and soft tissue infection or osteomyelitis. Presence of acute kidney injury (AKI) within 7 days was also evaluated. Categorical variables were compared using the Chi-square or Fisher’s exact tests, and continuous variables by t-test or Wilcoxon Rank Sum. Results Patients in the CZ+GM group were younger, with a mean age of 42.6 years compared to 50.6 years in the CRO+VA group (p = 0.02). Otherwise, there were no significant differences between groups in demographics, mechanism and site of injury, timeline of care, or total number of surgical interventions. More patients in the CZ+GM arm met the composite primary treatment failure outcome, but it was not statistically significant (45% vs 32%, p = 0.2). There were similar rates of treatment failure at 30 days (21% vs 26%, p = 0.5) and for only osteomyelitis (8% vs 9%, p = 1). Patients receiving CZ+GM trended towards higher rates of AKI, but this was not statistically significant (26% vs 19%, p = 0.4). Conclusion The trend in numerically lower treatment failure rates in the CRO+VA group across all outcomes studied supports the current recommendations in the local institutional guidelines. Given our sample size, type II error may have occurred, and larger studies with greater power should analyze this question. Disclosures Derek N. Bremmer, PharmD, BCPS-AQ ID, Thermo Fisher Scientific: Honoraria.