Simplified Evaluation Research Articles

Evaluation of cephalosporin allergy: Survey of drug allergy experts

BackgroundSince publication of the 2022 Drug Allergy Practice Parameters (DAPP) of the AAAAI and ACAAI it is unclear the extent to which the simplified and risk-stratified evaluation of cephalosporin allergy has been incorporated into allergy practice. ObjectiveWe aimed to assess current cephalosporin allergy testing practices using real case examples. MethodsAn 18-question REDCap survey was sent to the 136 members of the Adverse Reactions to Drugs, Biologics and Latex (ARDBL) Committee of the AAAAI between February-April 2023. ResultsForty-six (33.8%) ARDBL members completed the survey, following three email attempts. Most practicing in the United States (32, 69.6%), six (13.0%) in Canada, and the remaining from Europe and Asia. Almost half (47.7%) reported that the 2022 DAPP had increased their use of direct oral challenges. 91% would use cephalosporins in the setting of low-risk penicillin allergy history without testing. For low-risk cephalosporin reactions, 68% would perform a direct oral challenge (DOC) with the culprit drug. In severe immediate penicillin reactions, 23% would evaluate with penicillin-skin-testing before assessing cephalosporin allergy. For cephalosporin-related anaphylaxis, 48% would perform cephalosporin-based testing. For perioperative anaphylaxis with cefazolin, 57% would perform cephalosporin-based testing. For positive skin testing to cefazolin 79% chose to avoid the culprit drug with follow-up oral challenge to a structurally dissimilar cephalosporin. ConclusionIncreased uptake of DOC represents the initial impact of the 2022 DAPP. However, there is significant variation in testing practices of cephalosporin allergy even amongst drug allergy experts, reflecting a need for higher evidence base to guide consensus around testing higher risk reactions.

Development of a source-term migration model for a large bubble formed in a core disruptive accident

Because sodium-cooled fast reactors are designed with high inherent safety in mind, the probability of a core disruptive accident (CDA) is extremely low. However, from a defense-in-depth perspective, the study of CDA sequences is still worthwhile to assure the safety and reliability of reactors. During a CDA, a large bubble rapidly expands inside the sodium pool, rises from the core, and covers the gas region, providing a potential migration path for source terms (radioactive materials present within the containment barriers). Source terms released initially within the cover-gas region after a few hundred milliseconds are called instantaneous source terms. We propose here an instantaneous source-term migration model that provides a simplified evaluation of the amount of source terms absorbed by coolant sodium during the ascent of the CDA bubble. In the model, the particle motion within the CDA bubble obtained from the basic momentum equation is used to calculate the amount of source terms escaping from the bubble interface. In addition, a model analogous to aerosol scavenging by precipitation is used to assess the amount of source terms absorbed by droplets present in the bubble, especially the entrained sodium droplets that form during rapid expansion of the CDA bubble. The model is further validated by a previous source term migration experiment in which a large high-pressure bubble expands and rises in a sodium pool. Good agreement with the measured retention factor of a source term demonstrates the reliability of the developed model. Given these results, some key parameters are selected for a sensitivity analysis.

Improved Simplified Engineering Fault Displacement Hazard Evaluation Method for On-Fault Sites

The safety of high-potential risk facilities concerned with fault displacement hazards is a complex technical issue, especially if the fault is revealed beneath the facility during the operation. Applying simple conservative engineering hazard evaluation methods is rational if an urgent decision should be made to continue operation or implement protective measures. Engineering methods are being published for strike-slip on-fault sites and structures. Their crucial point is to estimate the probability of the rupture at the site intersection and consider the displacement distribution over the rupture length relative to the site’s on-fault location. It is shown in the paper that strict geometrical relations between the site location, length and initial point of the rupture determine whether the principal fault displacement intersects the site. The paper considers these geometrical parameters as independent random variables and applies a screening of ruptures contributing to the hazard. Magnitude- and on-fault coordinate-dependent empirical relations have been analysed and selected to evaluate the site displacements. The procedure resulted in realistic but conservative hazard curves for different on-fault site locations using data from the Paks site in Hungary. The results were compared to those obtained by the conservative engineering method for the same site and some published analyses.

Simplified evaluation method of shear strength characteristics of embankment materials applied to aseismic diagnosis of existing embankments

Simplified evaluation method of shear strength characteristics of embankment materials applied to aseismic diagnosis of existing embankments

Electrocardiographic abnormalities are associated with seropositive Trypanosoma cruzi infection status using a simplified cardiac diagnostic evaluation in dogs.

To describe associations between cardiac abnormalities and Trypanosoma cruzi serostatus by use of a simplified diagnostic evaluation in dogs at risk for T cruzi infection. A prospective, cross-sectional study was performed using a simplified diagnostic evaluation including high-sensitivity cardiac troponin I, 30-second ECG, and echocardiogram with 7 variables in 46 client-owned dogs from high-risk environments. Dogs were categorized as serologically positive (SP), negative (SN), or discordant (SD) by use of 2 antibody tests. Functional evaluation of cardiac health scores and blood PCR were obtained. Dogs were SP (n = 19), SN (17), and SD (10), with 9 PCR positive (7 SP, 1 SN, 1 SD). Troponin was above reference range in 6 of 46 (4 SP, 1 SN, 1 SD), and functional evaluation of cardiac health scores were 0 in all dogs. Conduction system abnormalities (prolonged interval durations, second-degree atrioventricular block, splintered QRS complex) and ventricular arrhythmias were documented in 8 (7 SP, 0 SN, 1 SD). Twenty-six (12 SP, 8 SN, 6 SD) had echocardiographic abnormalities, most often myxomatous mitral valve disease (MMVD) and left ventricular enlargement. Seropositive dogs were significantly older and had a higher likelihood of MMVD. Conduction system abnormalities were associated with positive serostatus. Echocardiographic abnormalities were complicated by MMVD and did not distinguish between serostatus. An ECG with assessment and detailed measurement of complexes and cardiac troponin I are simple tests to perform with abnormalities detected in seroreactive dogs. Electrocardiographic abnormalities in high-risk or seroreactive dogs should prompt further evaluation and monitoring of T cruzi infection.

On quadrature of highly oscillatory Bessel function via asymptotic analysis of simplex integrals

In this article, two methods for evaluating highly oscillatory Bessel integrals are explored. Firstly, a polynomial is analyzed as an effective approximation of the simplex integral of a highly oscillatory Bessel function based on Laplace transform, and its error rapidly decreases as the frequency increases. Furthermore, the inner product of f and highly oscillatory Bessel function can be approximated by two other forms of inner product by which one depends on a polynomial and the higher derivatives of f, another depends on Bessel function and the interpolation polynomial of f. In addition, three issues related to highly oscillatory Bessel integrals have also been discussed: inequalities for the convergence rate of Filon-type methods, evaluation of Cauchy principal values, and simplified evaluation on infinite intervals. Through some preliminary numerical experiments, our theoretical analysis has been preliminarily confirmed, and the proposed numerical method is accurate and effective.

Building Safety Evaluation and Improvement for Northern Vietnam Mountainous Environments Empirical Study Combining Japanese Experience with Local Conditions

This study addressed the insufficient structural strength and inadequate disaster resistance in building designs in the mountainous regions of Northern Vietnam. By integrating Japanese construction experience with local conditions, we proposed optimized building structures and simplified safety evaluation methods. Through an analysis of climate, terrain, geological hazards, soil conditions, and construction material costs, building design and foundation construction were optimized, and these optimizations were validated through wind tunnel experiments and finite element analysis. The results indicated that the optimized structures exhibited superior wind load stability, with external wind pressure coefficients ranging from −1.5 to −0.7, compared with the traditional structure’s range of −1 to −3.5. The redesigned foundation improved landslide resistance, reducing excavation and foundation construction costs relative to Japanese methods. The foundation’s safety factor reached 4.42–5.13, surpassing the standard of 2.5, and the retaining wall’s sliding resistance safety factor reached 1.87, exceeding the requirement of 1.5. These enhancements dramatically boosted building safety under extreme weather conditions. This study provides practical solutions for building design in Vietnam’s mountainous regions and serves as a valuable reference for similar research in other developing countries, underscoring significant practical and social implications.

Impact of the FIGO2023 staging system on endometrial cancer in Japan: differences between next-generation sequencing and simplified surrogate marker analysis.

The International Federation of Gynecology and Obstetrics (FIGO) revised the staging system of endometrial cancer in 2023. In this study, we aimed to determine stage transitions and prognosis of endometrial cancer using FIGO2008, FIGO2023 without molecular classification (FIGO2023), and FIGO2023 with molecular classification (FIGO2023m). Eighty-three patients diagnosed with endometrial cancer who underwent surgery and next-generation sequencing (NGS) molecular profiling as part of the Project HOPE cohort study were enrolled. Each case was staged according to the FIGO2008 and FIGO2023 criteria, and we evaluated changes in stage and disease-specific survival (DSS). Molecular classification based on NGS was performed to evaluate FIGO2023m, and the concordance rate with immunohistochemical marker analysis was assessed. Transitioning from FIGO2008 to FIGO2023 resulted in the restaging of 18 cases. Conversely, transitioning from FIGO2008 to FIGO2023m led to the restaging of 15 cases. The concordance rate between FIGO2023 and FIGO2023m staging was 96.4%. With FIGO2023m, the 5-year DSS was 97.6% for stage I (95% confidence interval [CI] 83.9-99.7), 83.3% for stage II (95% CI 56.8-94.3), 100% for stage III (95% CI NA), and 25.0% for stage IV (95% CI 0.9-66.5). Discrepancies in disease staging due to discordance between simplified surrogate marker analysis and NGS evaluation occurred in two cases. The revision of the staging system from FIGO2008 to FIGO2023 and FIGO2023m resulted in the restaging of several cases, with significant changes between stages I and II.

A Simplified Evaluation Framework for Adaptation Measures to Urban Heat Islands

Adaptation measures to urban heat islands are classified into the following three categories: measures to reduce solar radiation incident on the human body, measures to control and cool ground and wall surface temperature, and measures to control and cool the air and human body temperature. Case studies are conducted to evaluate the effects of the implementation of a cool water circulation sunshade and to examine the adverse effects of cool pavements on the human thermal environment, in addition to the effects of mist sprays on the human body. The effect of the sunshade, watering road, and mist spray, which are typical adaptation measures to urban heat islands, on the human thermal environment was estimated using Wet Bulb Globe Temperature (WBGT) as an indicator for heat stroke prevention and Standard New Effective Temperature (SET*) as an indicator for thermal comfort assessment. The effect of solar radiation shielding on improving the human thermal environment was the most significant, with a large decrease in the amount of solar radiation absorbed by the human body, resulting in a large decrease in SET* and WBGT of 2.7 °C and 1.0 °C, respectively, on fine summer days.

Prediction of peak overpressure from hydrogen-air cloud explosions in vented cylindrical vessels

Hydrogen as one of the most promising clean energies, has received a lot of attention. Intensive research has been devoted to developing techniques for the effective usage of hydrogen energy. However, hydrogen is prone to gas explosion incidents, which may impose significant threats to people and structures in the vicinity. Blast overpressure is one of the main hazards from hydrogen explosion incidents. A simplified evaluation method for the prediction of peak overpressure from hydrogen-air cloud explosions in vented cylindrical vessels is proposed. Detailed three-dimension numerical models of vented cylindrical vessels with premixed hydrogen-air clouds were generated and validated with testing data. The numerical simulation results were used to establish the empirical correlation between peak overpressure and cylindrical vessels parameters including length and diameter, vent size and vent activation pressure. The influence of ambient temperature in the vented cylindrical vessels on the peak overpressure is also discussed. The simplified prediction method could be used for quick and reliable prediction of the peak blast overpressures in vented cylindrical vessels from accidental hydrogen explosions.

A Simplified GBR Treatment and Evaluation of Posterior Seibert Class I Ridge Defects via Bio-collagen and Platelet-Rich Fibrin: A Retrospective Study.

Classical guided bone regeneration (GBR) treatments can achieve favorable clinical results for ridge defects. However, extensive bone augmentation in the non-esthetic area in the posterior region for minor ridge defects is unnecessary. Therefore, this study used a collagen and Platelet-rich fibrin (PRF) mixture for bone augmentation on minor posterior ridge defects and evaluated the effects. 22 Seibert Class I ridge defects were treated with BC and covered with a PRF membrane (simplified guided bone regeneration, simplified GBR) and other 22 were treated with Bio-Oss and covered with Bio-Gide (classical GBR). Cone-beam computed tomography imaging was conducted 6months post-surgery to compare the ridge's horizontal width (HW) and buccal ridge's horizontal width to assess the osteogenic effect. In addition, the buccal ridge contour morphology was studied and classified. The buccal ridge contour of simplified GBR was Type A in 14 cases, Type B in 7 cases, and Type C in 1 case and it of classical GBR was Type A in 11 cases, Type B in 8 cases, and Type C in 3 cases. The mean HW significantly increased by 1.50mm of simplified GBR treatment, while it increased by 1.83mm in classical GBR treatment. The combined use of BC and PRF had a significant effect on bone augmentation and this treatment exhibited promising clinical results for correcting posterior Seibert Class I ridge defects. The morphological classification of the reconstructive effect in this study can be utilized in future clinical work.

Swallowing Assessment in Post-Comatose Patients: A Feasibility Study on the SWADOC Tool.

Background: After a severe brain injury and a coma, patients may develop disorders of consciousness (DoC), frequently accompanied by severe dysphagia. The evaluation and therapy of swallowing are therefore essential aspects of their management. Objectives: This study aims to evaluate the SWallowing Assessment in Disorders of Consciousness (SWADOC) tool in the assessment of swallowing in post-comatose patients. Here, we validate its quantitative items, describe preliminary results and identify limitations. Methods: Fourteen post-comatose patients were repeatedly evaluated with the Simplified Evaluation of CONsciousness Disorders (SECONDs) and with the SWADOC. Results: The internal consistency of the oral and pharyngeal subscales of the SWADOC was good. The test-retest reliability showed that all items, all subscores and the total score were stable except for two items (endo-buccal secretions and bronchial congestion). A comparison to the Facial Oral Tract Therapy Swallowing Assessment of Saliva (F.O.T.T-SAS) confirmed that scoring with the SWADOC offers a greater potential for quantitative observations in assessing swallowing abilities among patients with DoC. The SECONDs scores and SWADOC total scores showed a significant positive correlation (τ = 0.78, p < 0.001). Conclusions: This study provides preliminary but encouraging results on the psychometric properties of the SWADOC tool. It shows that this tool is relevant and feasible as a bedside assessment of dysphagia in patients with DoC.

Experimental feasibility analysis of quantum/classical coexistence over fibre and free space links

AbstractThe authors present a novel approach to Quantum Key Distribution (QKD) research, emphasising cost‐effectiveness and practicality using a single photon polarisation‐encoded system employing mainly commercial off‐the‐shelf components. This study diverges from previous high‐cost, high‐end setups by exploring the viability of QKD in more accessible and realistic settings. Our approach focuses on practical measurements of the signal‐to‐noise ratio by analysing polarisation‐encoded photonic qubits over various transmission scenarios. The authors introduce a simplified evaluation method that incorporates experimental measurements, such as noise sources and losses, into a semi‐empirical theoretical framework. This framework simulates the standard DS‐BB84 protocol to estimate Secure Key Rates (SKRs), offering an alternative approach on the evaluation of the practical implementation of QKD. Specifically, the authors examine the feasibility of QKD over a 2.2 km intra‐campus fibre link in coexistence scenarios, identifying optimal Wavelength‐Division Multiplexing allocations to minimise Raman noise, achieving an expected SKR of up to 300 bps. Additionally, the authors’ study extends to 40 m indoor and 100 m outdoor Free‐Space Optical (FSO) links using low‐cost components, where the authors recorded Quantum Bit Error Rate (QBER) values below 3.2%, allowing for possible SKRs up to 600 bps even in daylight operation. The converged fibre/FSO scenario demonstrated robust performance, with QBER values below 3.7% and an expected SKR of over 200 bps. Our research bridges the gap between high‐end and economical QKD solutions, providing valuable insights into the feasibility of QKD in everyday scenarios, especially within metropolitan fibre based and FSO links. By leveraging cost‐effective components and a simplified single photon exchange setup, the authors work paves the way for the effortless characterisation of deployed infrastructure, highlighting its potential in diverse settings and its accessibility for widespread implementation.

Mitraclip Versus Medical Therapy or Surgery in Patients With Mitral Regurgitation: Long-Term Outcomes Determined by the Reconstruction of Individual Patient Data.

Although MitraClip has been studied in numerous trials, its evidence in the long term is basedon a few original studies. We used an original technique of evidence synthesis to review long-termcomparative trialsevaluating MitraClip. We searched the PubMed database to select long-term comparative trials of MitraClip. The endpoint was all-cause mortality (minimum follow-up, one year). Included trials were analyzed using theIPDfromKM (reconstruct Individual Patient Data from published Kaplan-Meier survival curves)method to reconstruct individual patient data from Kaplan-Meier curves. Standard survivalstatistics were used to interpret these long-term efficacy data. The survival benefit per patient was estimatedfrom the restricted mean survival time (RMST). Six comparative studies of MitraClip were included; 973 patients were treated with MitraClip (six arms), 717 with medical therapy (five arms), and 80 with surgical repair or replacement (one arm). In our mainanalysis, the outcomes observed in patients treated with MitraClip were significantly better than thoseof medical therapy (hazard ratio for all-cause mortality, 0.5276; 95% confidence interval, 0.4412 to 0.6309;p < 0.001); the number of patients treated with surgery was too small to make reliable comparisons. Mediansurvival was 30.4 months for medical therapy versus not reached for the other two groups. RMST was 43.931 and33.756 monthsfor MitraClip and controls, respectively, yielding a gain per patient of 10.17 months (95%confidence interval, 7.47 to 12.88). In our simplified cost-effectiveness evaluation, a gain of approximately10 months per patient compared favorably with the device cost.Our analysis provided an original interpretation of the long-termevidence available on MitraClip.

Effect of drying and milling industrial potato peel for recovering phenolic and antioxidant compounds: Optimization process and economic evaluation

Currently, industrial potato peel (PP) represents a cost to the industry and a potential burden on the environment. This study aims to discuss the need to dry and mill PP before extracting phenolic and antioxidant compounds, aiming to achieve the most profitable strategy to valorize the residue without introducing irrelevant and expensive processes. A design of experiments and a simplified economic evaluation were used to compare the two scenarios: PP without pre-treatment and after drying and milling (PPt). A central composite design with two factors (ethanol concentration and solid/liquid ratio) was performed aiming to maximize two response variables (concentration of phenolic compounds in the extract and antioxidant activity). A maximum of 46.9 ± 2.6 mg GAE/g dry extract and an IC50 of 900 mg/L was achieved by extracting PPt with 50 % ethanol. For PP extraction, only ethanol concentration was revealed to be important, achieving an extract with 22.8 ± 0.8 mg GAE/g dry extract and an IC50 of 900 mg/L with 60 % ethanol. The economic analysis showed that the reduced extraction yield and the increment in ethanol used for extracting potato peel without pre-treatment significantly affected the operating costs. A more economic scenario is achieved by drying and milling PP.

A simplified machine learning product carbon footprint evaluation tool

On the way to climate neutrality manufacturing companies need to assess the Carbon dioxide (CO2) emissions of their products as a basis for emission reduction measures. The evaluate this so-called Product Carbon Footprint (PCF) life cycle analysis as a comprehensive method is applicable, but means great effort and requires interdisciplinary knowledge. Nevertheless, assumptions must still be made to assess the entire supply chain. To lower these burdens and provide a digital tool to estimate the PCF with less input parameter and data, we make use of machine learning techniques and develop an editorial framework called MINDFUL. This contribution shows its realization by providing the software architecture, underlying CO2 factors, calculations and Machine Learning approach as well as the principles of its user experience. Our tool is validated within an industrial case study.

PRECISE-DAPT, ARC-HBR, or Simplified Clinical Evaluation for the Prediction of Major Bleeding After Percutaneous Coronary Intervention in older Patients

Elderly patients have been remarkably under-represented in bleeding risk cohorts. Thus, the PRECISE-DAPT and ARC-HBR scores are not validated in older adults. Therefore, we sought to evaluate the PRECISE-DAPT and ARC-HBR scores in an exclusively elderly population and furthermore assess the prognostic value of a truly simplified clinical evaluation (SCE), consisting of only 3 binary clinical variables (hemoglobin <11g/dL, prior bleeding and anticipated use of anticoagulants). This is a retrospective analysis of the prospective single-center Elderly-HCD registry. Consecutive patients of ≥75 years of age that underwent percutaneous coronary intervention in the period of 2012-2019 were included. The primary endpoint was post discharge bleeding (PDB) at 12 months follow-up, defined according to the BARC 3/5 criteria. A total of 693 patients with a mean age of 81 (± 4.4) years were included in the study and 60 (6.8%) patients met the primary endpoint. The PRECISE-DAPT and ARC-HBR scores did not significantly predict PDB in Cox-regression models (HR: 1.65 (0.78-3.42) and 1.46 (0.72-4.24), respectively), whereas the SCE outperformed both scores (HR: 2.47 (1.34-4.49)). All 3 scores exhibited a moderate discriminatory potential as determined by ROC-curve analysis (AUCs 0.601, 0.621 and 0.616, respectively) with no significant differences when comparing either of them. The SCE showed an IDI of 0.25, p=0.02 (SCE vs ARC-HBR) and 0.24, p=0.01 (SCE vs PRECISE-DAPT); with NRI of 6.54%, p=0.37 and 7.12%, p=0.43, respectively. In conclusion, both the PRECISE-DAPT score and ARC-HBR criteria showed insufficient predictive value in older adults. A truly SCE, consisting of 3 easily accessible variables, not only provides equal discriminatory potential but also demonstrates superior predictive value as determined by cox-regression models. This makes it a highly appealing tool for risk stratification, pending its evaluation in larger prospective studies.

Numerical analysis of thermal and mechanical characteristics with property maps in complex semiconductor package designs

As semiconductor performance improves through advanced package designs, it becomes important to consider both thermal and mechanical properties. Better understanding their relationship enhances system design and optimization. This study has introduced a numerical method that takes into account both thermal and mechanical fluxes to construct thermal and mechanical property maps for practical application in semiconductor engineering. Furthermore, this paper investigated the relationship between the two properties using the constructed property maps in commercially available semiconductor packages. Owing to the complexity of packaging design patterns, a coupled isoparametric mapping and machine learning (ML) method was introduced to investigate their effects. The model then determines and investigates the anisotropic equivalent thermal and mechanical properties of the commercialized semiconductor packages with complex pattern designs, according to the package materials, volume fractions of each material, and design patterns. This approach pursues more sophistication and practicality compared to simplified composite structure property evaluation models. Additionally, all processes in the algorithm are automated based on ML methods, making them practically applicable in the semiconductor industry. The study shows that there is a strong correlation between the thermal and mechanical characteristics in the complex package patterns. This relationship was able to form a fairly clear category based on the shape of the dielectric band because the dielectric band had significantly different effects on the thermal and mechanical fluxes. The study discussed the physical implications of the similarities and differences between the two behaviors and validated the results of the equivalent properties through finite element (FE) analysis. Finally, the study cross-validates the relationship by showing that information from one flux behavior can be used to predict the other based on the ML method. Based on the results, this paper can provide a better understanding of thermal and mechanical fluxes in semiconductor package patterns for package design and optimization.

Association of METS-IR index with prevalence of erectile dysfunction in US adults: a cross-sectional study.

Insulin resistance (IR) is involved in the development of erectile dysfunction (ED). The purpose of this study was to assess the correlation between the metabolic score for IR (METS-IR) index and risk of erectile dysfunction in US adults. This study selected individuals from the National Health and Nutrition Examination Survey (NHANES). Logistic regression analysis, subgroup analysis, and dose-response curve analysis were carried out to assess the relationship between the METS-IR index and ED prevalence. This study ultimately included 1759 participants aged ≥ 20years, of whom 512 self-reported a history of ED. After adjusting for all confounders, each unit increase in METS-IR index was associated with a 3% increase in erectile dysfunction prevalence (OR = 1.03, 95% CI: 1.01-1.04). In almost all subgroups, an increased METS-IR index was associated with a higher prevalence of ED. The dose-response curve displayed a positive non-linear connection between METS-IR value and the prevalence of ED. The study found a positive association between the METS-IR index and ED. METS-IR is useful as a simplified IR evaluation index for early identification of people with high risk of ED.

Manipulation and Wakefield Effects on Multi-Pulse Driver Beams in PWFA Injector Stages

Particle-driven plasma wakefield acceleration (PWFA) exploits the intense wakefields excited in a plasma by a high-brightness driver beam in order to accelerate a trailing, properly delayed witness electron beam. Such a configuration offers notable advantages in achieving very large accelerating gradients that are suitable for applications in particle colliders and photon production. Moreover, the amplitude of the accelerating fields can be enhanced by resonantly exciting the plasma using a multi-pulse driver beam with a proper time structure. Before the injection into the plasma stage, the pulsed electron beam, conventionally termed the comb beam, is usually produced and pre-accelerated in a radio-frequency (RF) linear accelerator (linac). In this pape, we discuss challenging aspects of the dynamics that comb beams encounter in the RF injector stage preceding the plasma. In particular, the examples we analyze focus on the use of velocity bunching to manipulate the time structure of the beam and the impact of dipole short-range wakefields on the transverse emittances. Indeed, both processes crucially affect the phase space distribution and its quality, which are determinant features for an efficient acceleration in the plasma. In addition, the analyses we present are performed with the custom tracking code MILES, which utilizes semi-analytical models for a simplified evaluation of wakefield effects in the presence of space charge forces.