Design, Manufacturing, and Analysis of Periodic Three-Dimensional Cellular Materials for Energy Absorption Applications: A Critical Review.

Cellular materials offer industries the ability to close gaps in the material selection design space with properties not otherwise achievable by bulk, monolithic counterparts. Their superior specific strength, stiffness, and energy absorption, as well as their multi-functionality, makes them desirable for a wide range of applications. The objective of this paper is to compile and present a review of the open literature focusing on the energy absorption of periodic three-dimensional cellular materials. The review begins with the methodical cataloging of qualitative and quantitative elements from 100 papers in the available literature and then provides readers with a thorough overview of the state of this research field, discussing areas such as parent material(s), manufacturing methods, cell topologies, cross-section shapes for truss topologies, analysis methods, loading types, and test strain rates. Based on these collected data, areas of great and limited research are identified and future avenues of interest are suggested for the continued maturation and growth of this field, such as the development of a consistent naming and classification system for topologies; the creation of test standards considering additive manufacturing processes; further investigation of non-uniform and non-cylindrical struts on the performance of truss lattices; and further investigation into the performance of lattice materials under the impact of non-flat surfaces and projectiles. Finally, the numerical energy absorption (by mass and by volume) data of 76 papers are presented across multiple property selection charts, highlighting various materials, manufacturing methods, and topology groups. While there are noticeable differences at certain densities, the graphs show that the categorical differences within those groups have large overlap in terms of energy absorption performance and can be referenced to identify areas for further investigation and to help in the preliminary design process by researchers and industry professionals alike.

Crashworthiness of 3D Lattice Topologies under Dynamic Loading: A Comprehensive Study.

Periodic truss-based lattice materials, a particular subset of cellular solids that generally have superior specific properties as compared to monolithic materials, offer regularity and predictability that irregular foams do not. Significant advancements in alternative technologies-such as additive manufacturing-have allowed for the fabrication of these uniquely complex materials, thus boosting their research and development within industries and scientific communities. However, there have been limitations in the comparison of results for these materials between different studies reported in the literature due to differences in analysis approaches, parent materials, and boundary and initial conditions considered. Further hindering the comparison ability was that the literature generally only focused on one or a select few topologies. With a particular focus on the crashworthiness of lattice topologies, this paper presents a comprehensive study of the impact performance of 24 topologies under dynamic impact loading. Using steel alloy parent material (manufactured using Selective Laser Melting), a numerical study of the impact performance was conducted with 16 different impact energy-speed pairs. It was possible to observe the overarching trends in crashworthiness parameters, including plateau stress, densification strain, impact efficiency, and absorbed energy for a wide range of 3D lattice topologies at three relative densities. While there was no observed distinct division between the results of bending and stretching topologies, the presence of struts aligned in the impact direction did have a significant effect on the energy absorption efficiency of the lattice; topologies with struts aligned in that direction had lower efficiencies as compared to topologies without.

Colonoscopy screening for colorectal cancer in Egypt: a nationwide cross-sectional study.

BACKGROUND: Current guidelines advocate for colorectal cancer (CRC) screening in adults who are at risk by using direct visualization methods such as colonoscopy. However, in Egypt, there is a paucity of data regarding the current practice of colonoscopy screening. Moreover, more information is needed about the knowledge and attitudes of potential participants regarding the procedure and possible barriers that can limit their participation. METHODS: We conducted a nationwide cross-sectional study using an interview-based survey of patients aged 45 years or above who presented to outpatient clinics of nine university hospitals throughout Egypt. Participants were surveyed to assess their compliance with CRC colonoscopy screening guidelines, their knowledge of and attitude towards colonoscopy screening, and their perspective on potential barriers to colonoscopy screening. RESULTS: A total of 1,453 participants responded to our survey in the nine study centers. Only a minority of participants (2.3%) were referred for CRC screening. Referral rates were higher among those who knew someone with a history of CRC (5.3% vs 1.5%, p < 0.001) or had a discussion with their physician about CRC (25.8% vs 0.7%, p < 0.001). Few responders (3.2%) had good knowledge regarding CRC screening. After introducing the concept of CRC screening to all participants, most patients (66.7%) showed a positive attitude towards having the procedure. Financial burden and fear of results were the two most frequently cited barriers to undergoing CRC screening (81.1%; and 60.1%, respecteively). CONCLUSIONS: Despite the positive attitude, there is insufficient knowledge about CRC screening among eligible participants in Egypt. This has probably contributed to low compliance with current CRC screening guidelines and needs to be addressed at the national level.

Effective Mechanical Properties of Periodic Cellular Solids with Generic Bravais Lattice Symmetry via Asymptotic Homogenization.

In this paper, the scope of discrete asymptotic homogenization employing voxel (cartesian) mesh discretization is expanded to estimate high fidelity effective properties of any periodic heterogeneous media with arbitrary Bravais's lattice symmetry, including those with non-orthogonal periodic bases. A framework was developed in Python with a proposed fast-nearest neighbour algorithm to accurately estimate the periodic boundary conditions of the discretized representative volume element of the lattice unit cell. Convergence studies are performed, and numerical errors caused by both voxel meshing and periodic boundary condition approximation processes are discussed in detail. It is found that the numerical error in periodicity approximation is cyclically dependent on the number of divisions performed during the meshing process and, thus, is minimized with a refined voxel mesh. Validation studies are performed by comparing the elastic properties of 2D hexagon lattices with orthogonal and non-orthogonal bases. The developed methodology was also applied to derive the effective properties of several lattice topologies, and variation of their anisotropic macroscopic properties with relative densities is presented as material selection charts.

Evaluation of small hydropower turbines installed downstream of Nile River branches (Egypt).

The current study proposes a new strategy for using small hydroelectric turbines in downstream river branches with the least amount of construction and the lowest cost by comparing two different methods of installing the turbines, the first by installing the turbines at the river's bottom and the second by installing the turbines on floating boats. The methodology of this article is based on predicting the distribution of velocities through the watercourse using experimental data collected at various points in the river's depth, and then predicting the resulting electrical power for different sizes of turbines, as well as estimating the number of turbines for each row and the number of rows along the river. Therefore, Investigate the proposed systems. The proposed small hydropower system's economic viability and environmental impact are investigated in this article. According to the nature of the waterway, the best diameter of a turbine that can be used is 1.5 m based on water velocities and river depths. The proposed power plant generated 25.8 kW per single turbine row, with an estimated cost of produced power (0.035 USD/kWh) of approximately 20 turbines installed per row. Compared to other renewable energy sources, the proposed hydropower system is cost-effective and environmentally friendly, as generating electricity with the proposed small hydropower plant could reduce annual carbon dioxide emissions by 368 tones of CO2 per single turbine row.

Percutaneous Closure of Post-infarct Left Ventricular Pseudoaneurysm: A Review of Literature.

Left ventricular pseudoaneurysm is a well-known complication of myocardial infarction and open-heart surgery and has recently been described as succeeding transapical transcatheter aortic valve replacement. While surgical intervention is the conventional therapeutic approach, transcatheter closure can be considered in patients at high risk for surgical procedures. In this article, we present a postmyocardial infarction pseudoaneurysm for which closure was done via retrograde left ventricular access using an Amplatzer Septal Occluder, and provide a review of recent literature focusing on indications and outcomes of the different percutaneous techniques and devices.

Parametric optimisation for the design of gravity energy storage system using Taguchi method.

Gravitational energy storage systems are among the proper methods that can be used with renewable energy. However, these systems are highly affected by their design parameters. This paper presents a novel investigation of different design features of gravity energy storage systems. A theoretical model was developed using MATLAB SIMULINK to simulate the performance of the gravitational energy storage system while changing its design parameters. A parametric optimization study was also conducted using Taguchi and analysis of variance (ANOVA) techniques for optimizing the energy storage rate. Six parameters were studied; three are related to the piston design (diameter, height, and material density). The other parameters are the return pipe diameter, length, and charging/discharging time. Results revealed that the piston diameter and height are the two most significant parameters for the system performance compared to the other parameters, as they contributed by 35.11% and 30.28%, respectively. The optimization results indicated that the optimal piston diameter, height, and return pipe diameter were 0.25, 0.5, and 0.01 of the container height. The outcomes of this paper can significantly improve energy storage and power generation from renewable energy systems as it provides a reliable, economical, sustainable, and durable energy storage system.

Subsidence of Spinal Fusion Cages: A Systematic Review.

BACKGROUND: Although many research studies investigating subsidence of intervertebral fusion cages have been published, to our knowledge, no study has comprehensively compared cage subsidence among all lumbar intervertebral fusion (LIF) techniques. This study aimed to review the literature reporting evidence of cage subsidence linked to LIF. The amount of subsidence was compared and associated with the procedures and corresponding implants used, and the effect of cage subsidence on clinical outcomes was investigated. METHODS: For this systematic review, the MEDLINE and PubMed databases were used to identify relevant studies. Search terms included lumbar, lumbar vertebrae, lumbar spine, cage, spinal fusion, prosthesis, prosthesis implantation, implantation, implants, interbody, spacer, and subsidence. Studies included in this review were those having more than 10 patients and reporting the amount of subsidence observed using computed tomography or x-ray imaging after surgery and at follow-up visits after a minimum of 6 weeks postsurgery. Data and scale definitions related to subsidence were extracted from articles for comparison of subsidence prevalence between the 5 LIF surgical procedures. RESULTS: Forty articles were identified for inclusion. The review included data from 390 anterior lumbar intervertebral fusions (ALIFs), 2130 lateral lumbar intervertebral fusions (LLIFs), 560 posterior lumbar intervertebral fusions (PLIFs), 245 oblique lumbar intervertebral fusions (OLIFs), and 1634 transverse lumbar intervertebral fusions (TLIFs) for a total of 4959 patients who underwent LIF surgery. The minimum and maximum percentages of the number of patients having subsidence for each procedure in the included studies were as follows: ALIF stand-alone, 6% and 23.1%; LLIF stand-alone, 8.7% and 39.6%; LLIF with posterior fixation, 3.3% and 20.7%; OLIF with posterior fixation, 4.4% and 36.9%; PLIF with posterior fixation, 7.4% and 31.8%; and TLIF, 0.0% and 51.2%. CONCLUSIONS: The number of patients experiencing subsidence varied between studies within each fusion procedure. Our findings indicate that all 5 surgical methods are at risk of subsidence. Overall, ALIF without posterior fixation resulted in the lowest reported subsidence occurrence among the 5 surgical approaches. There is conflicting evidence on the association between subsidence and negative clinical outcomes. CLINICAL RELEVANCE: This review defines and compares subsidence incidence between all LIF procedures and investigates the risk of symptomatic clinical outcomes.

Large tricuspid valve thrombus complicating COVID-19 pneumonia.

BACKGROUND: Hemostatic disturbances with coronavirus disease 2019 (COVID-19) can predispose to tricuspid and right heart thrombi in very rare instances. AIM: We describe a 29-year-old female patient without a previous cause of thrombosis who developed large tricuspid valve thrombus (TVT) and moderate-to-severe tricuspid regurgitation (TR) during the course of COVID-19 infection. MATERIALS AND METHODS: Persistant fever and tachycardia with thrombocytopenia and high d-dimer increased the index of suspicion. The diagnosis was made by bedside transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR). Surgery was performed for thrombectomy and tricuspid valve replacement with a tissue valve. DISCUSSION AND CONCLUSION: Detection of TVT in COVID-19 patients on the basis of high index of suspicion, bedside TTE and noninvasive CMR helps early surgical treatment and subsequent reduction of mortality and hospital stay.

Total hip replacements following acetabular fractures. 7 to 15 years clinical and radiological results.

This study is reporting the long term clinical and radiographic results of a group of 45 patients who underwent total hip arthroplasty following acetabular fractures. The study included 39 males and 6 females. The age of the patients ranged from 32 to 61 with a mean of 46.4 years. The indication for surgery was secondary osteoarthritis in 35 patients and avascular necrosis of the femoral head in the remaining ten. The follow up period ranged from 7 to 15 years with a median of 10.3 years. Uncemented total hip prostheses were used in 37 cases while 8 cases had hybrid prostheses with cemented cups and uncemented stems. Thirty patients (66.7%) needed autogenous acetabular bone grafting. There has been a statistically significant improvement from a preoperative mean Oxford hip score of 16 to a postoperative mean score of 39.8 (p < 0.001). At the end of follow up, two cases had revision for cup loosening. The complications included one case of transient sciatic nerve palsy, and two cases of heterotopic ossification. Currently, total hip replacement remains the best option for end stage post traumatic arthritis. There are technical challenges associated with this replacement surgery which the surgeon should be aware of.

Anxiety is associated with extraneous cognitive load during teaching using high-fidelity clinical simulation.

High-fidelity clinical simulation is currently a well-established teaching tool. However, high-fidelity representations of patients in critical conditions have the potential to elicit emotions among learners and impact their cognitive load (CL). Teaching with clinical simulation may induce both emotional and cognitive overloads. The relationship between anxiety and CL during clinical simulation was studied. Forty-one undergraduate medical students participated in this study; 19 males and 22 females. The state-anxiety component of State-Trait Anxiety Inventory was administered during clinical simulation teaching sessions at time points: pre-scenario, post-scenario and post-debriefing. The Cognitive Load Scale (Leppink et al.) questionnaire was also completed post-scenario. This assessed the three components of CL: intrinsic cognitive load (ICL), extraneous cognitive load (ECL) and self-perceived learning (SPL). Median CL scores for ICL, ECL and SPL were compared between groups of low-anxiety and high-anxiety participants using a Mann-Whitney U test. State-anxiety scores were high for both the pre-scenario and post-scenario time points with a significant reduction following post-debriefing. The median (interquartile range) state-anxiety scores were 41.0 (33.0-50.0), 46.0 (33.0-52.0) and 31.0 (23.0-39.0) for the pre-scenario, post-scenario and post-debriefing time points respectively. Students with high state-anxiety had higher ECL scores (median = 2.0) than students with low state-anxiety (median = 0.9) at the post scenario time point (U = 220, p = 0.043). No statistical relation was seen with state-anxiety for either ICL or SPL. State-anxiety immediately after the simulation scenario is associated with ECL but not ICL or SPL.

Laparoscopic Repair of Pediatric Inguinal Hernia: Disconnection of the Hernial Sac Versus Disconnection and Peritoneal Closure.

Background/Purpose: Many techniques have been described for the treatment of pediatric inguinal hernia (PIH). Some authors emphasized the importance of disconnecting the sac, to create a scar, and to close the peritoneum mimicking the open approach. Others stated that peritoneal disconnection alone is enough for treatment of PIH regardless of the size of the internal ring. In this study, we compare the short-term results of laparoscopic disconnection of PIH sac versus disconnection and peritoneal closure. Patients and Methods: The study was carried from March 2016 to March 2017, on 34 patients with 40 PIH. Patients were randomly divided into two groups: group A, subjected to laparoscopic hernia sac disconnection and group B, subjected to laparoscopic hernia sac disconnection with peritoneal closure. Both groups were compared regarding the operative details, including complications and conversion, postoperative complications and recurrence. Results: Group A included 20 hernias in 15 patients, whereas group B included 20 hernias in 19 patients. The age ranged from 1 to 23 months. In group A, the mean operative time (OT) was 34.6 and 39.4 minutes, for unilateral and bilateral cases, respectively, whereas in group B, it was 45.1 minutes for unilateral cases and 65 minutes for 1 bilateral case. The OT was significantly shorter in group A for unilateral cases. There was no conversion and no intraoperative complications. Three recurrences occurred in group A (15% of hernias/20% of cases) with no recurrences in group B; difference was statistically insignificant. All 3 recurrences occurred in hernias with an internal ring diameter (IRD) >10 mm. Hospital stay was statistically shorter in group B. Conclusion: Both laparoscopic sac disconnection with internal ring closure and sac disconnection only are safe and effective treatments of PIH. However, the latter technique is not recommended for cases with IRD >10 mm because of the unacceptable high recurrence with rings >10 mm.

Heart-type fatty acid-binding protein as a predictor of cardiac ischemia in intractable seizures in children.

BACKGROUND: Children with intractable epilepsy have chronic dysfunction of the autonomic nervous system causing myocardial ischemia. Heart-type fatty acid-binding protein (H-FABP) is a sensitive biomarker for myocardial ischemia. AIMS: We aimed to evaluate serum levels of H-FABP during seizures compared to their interictal levels and healthy controls and changes in heart rate (HR) and HR variability (HRV) in epileptic children with intractable seizures. MATERIALS AND METHODS: We included 30 epileptic seizures in 25 children with intractable epilepsy and 30 matched controls. They were subjected to video-electroencephalography monitoring simultaneously with Holter electrocardiogram and measurement of H-FABP. RESULTS: Mean serum levels of H-FABP were increased significantly in patients either in the ictal or interictal periods compared to that in the controls (P < 0.001 and P< 0.01, respectively). There is no significant difference in serum levels of the H-FABP in the ictal and interictal periods. The basal time domain measures of HRV were significantly lower in the patient group compared to the control group. CONCLUSION: H-FABP might suggest a degree of myocardial ischemia in intractable epilepsy. HRV is impaired in patients with refractory seizures.

Analysis of loco-regional and distant recurrences in breast cancer after conservative surgery.

BACKGROUND: A number of patients treated conservatively for breast cancer will develop loco-regional and distant recurrences. Our aim was to determine how their occurrence may be linked to the evolution of the disease. METHODS: We analyzed 238 women treated by conservative breast surgery and breast irradiation in a single institution. We evaluated the prognostic factors associated with loco-regional and distant recurrences and the prognostic value of local and regional recurrences on systemic progression. RESULTS: After a median follow-up of 5 year (range 1-10), 16 (6.72%) patients in the breast conservative surgery (BCS) groups had loco-regional recurrence. For distant recurrence, 10 (4.2%) patients had experienced distant recurrence. Lympho-vascular invasion (HR 2.55; 95% CI, 076 to 8.49) and an extensive intraductal component (HR, 2.22; 95% CI, 0.69 to 7.15) and nodal status are risk factors for loco-regional recurrence (LRR) after breast conservative therapy (BCT). Tumor size, nodal status, high histologic grade, and breast cancer diagnosed at a young age (≤35 years) are correlated with higher distant recurrence rates after BCT. CONCLUSIONS: Risk factors for LRR after BCS include lympho-vascular invasion, extensive inraductal component, and high nodal status, where as risk factors for distant recurrence include tumor size, nodal status, high histologic grade, and breast cancer diagnosed at a young age (≤35 years).

Value of electroencephalographic monitoring in newborns with hypoxic-ischemic encephalopathy treated with hypothermia.

BACKGROUND: The values of electroencephalography (EEG) in neonatal hypoxic-ischemic encephalopathy (HIE) during therapeutic hypothermia (TH) are still uncertain. AIMS: The aim of this study is to detect EEG background, the prevalence of seizures during cooling, and to determine different EEG patterns that can predict brain injury in magnetic resonance imaging (MRI). PATIENTS AND METHODS: Thirty-nine newborns with HIE were subjected to TH. Continuous monitoring by video-EEG was carried out throughout cooling and during rewarming. MRI was done for all newborns after rewarming. The predictive value of EEG background for MRI brain injury was evaluated at 6-h intervals during cooling and rewarming. RESULTS: At all-time intervals, normal EEG was associated with no or mild MRI brain injury. At the beginning of cooling, normal background was more predictive of a favorable MRI outcome than at later time points. After 24 h of monitoring, diffuse burst suppression and depressed patterns had the greatest prognostic value. In most patients, a discontinuous pattern was not associated with poor prognosis. Thirty-one percent developed electrical seizures, and 8% developed status epilepticus. Seizures were subclinical in 42%. There is a significant association between duration of seizure patterns detected on the EEG and severity of brain injury on MRI. CONCLUSIONS: Continuous EEG monitoring in newborns with HIE under cooling has a prognostic value about early MRI brain injury and identifies electrographic seizures, approximately 50% of which are subclinical. Treatment of clinical and subclinical seizure results in a reduction of the total duration of seizure pattern supports the hypothesis that subclinical seizures should be treated.

Incidence and characteristics of HBV reactivation in hematological malignant patients in south Egypt.

AIM: To investigate characteristics of hepatitis B virus (HBV) implicated in HBV reactivation in patients with hematological malignancies receiving immunosuppressive therapy. METHODS: Serum samples were collected from 53 patients with hematological malignancies negative for hepatitis B surface antigen (HBsAg) before the start of and throughout the chemotherapy course. HBV reactivation was diagnosed when the HBsAg status changed from negative to positive after the initiation of chemotherapy and/or when HBV DNA was detected by real-time detection polymerase chain reaction (RTD-PCR). For detecting the serological markers of HBV infection, HBsAg as well as antibodies to the core antigen (anti-HBc) and to the surface antigen were measured in the sera by CEIA. Nucleic acids were extracted from sera, and HBV DNA sequences spanning the S gene were amplified by RTD-PCR. The extracted DNA was further subjected to PCR to amplify the complete genome as well as the specific genomic sequences bearing the enhancer II/core promoter/pre-core/core regions (nt 1628-2364). Amplicons were sequenced directly. RESULTS: Thirty-five (66%) of the 53 HBsAg-negative patients were found to be negative serologically for anti-HBc, and the remaining 18 (34%) patients were positive for anti-HBc. Five of the 53 (9.4%) patients with hematologic malignancies experienced HBV reactivation. Genotype D1 was detected in all five patients. Four types of mutant strains were detected in the S gene product of HBV strains and were isolated from 3 patients with HBV reactivation: T/S120, L143, and I126. HBV DNA was detected in the pretreatment HBsAg-negative samples in one of the five patients with HBV reactivation. In this patient, sequences encompassing the HBV full genome obtained from sera before the start of chemotherapy and at the time of de novo HBV hepatitis were detected and it showed 100% homology. Furthermore, in the phylogenetic tree, the sequences were clustered together, thereby indicating that this patient developed reactivation from an occult HBV infection. CONCLUSION: Past infection with HBV is a risk factor for HBV reactivation in Egypt. Mandatory anti-HBc screening prior to chemotherapy in patients with hematological malignancies is recommended.

Adult Wilms' tumor: review of literature.

BACKGROUND: The most common renal tumors in adults is renal cell carcinoma. Wilms' tumor in subjects older than 16 years is rare; only 3% of Wilms' tumors are reported in adults, which explain the difficulties in diagnosis and treatment of this tumor entity in this age group. METHODS: Patient with stage IV adult nephroblastoma with favorable histology was described, current treatment modalities were discussed, and the literature was reviewed. RESULTS: Nineteen year old female patient is presented with renal mass, abdominal lymphadenopathy, and bilateral pulmonary deposits. Sonar guided biopsy from the renal mass was taken and pathology revealed nephroblastoma. Right nephrectomy was performed and the pathological examination revealed classic histology of nephroblastoma. The case diagnosed as stage IV adult Wilms' tumor with favorable histology. According to National Wilms' Tumor Study Group (NWTS-3), multimodal therapy was initiated immediately after surgery. The patient failed to respond to the first line therapy and died due to disease progression. CONCLUSION: Adult Wilms' tumor has no specific guidelines and this may lead to improper or incorrect treatment.

Preoperative embolization in surgical management of massive thoracic tumors.

BACKGROUND: The surgical excision of a highly vascular giant tumor may be challenging. The aim of this study was to describe our experience with preoperative percutaneous embolization of massive vascular chest tumors before surgical excision. METHODS: From 2009 to 2011, 8 cases of giant vascular thoracic tumor were treated at Assiut University Hospital, Assiut, Egypt, by preoperative embolization of the feeding arteries followed by successful excision after 48 h. RESULTS: The median age of the 8 patients was 39 years. Embolization of their tumors resulted in a reduction of tumor size, and minimal blood loss was observed perioperatively. Perilesional edema and easy differentiation of ischemic tissue facilitated complete surgical removal of the tumors. CONCLUSIONS: Preoperative embolization of giant vascular thoracic tumors is useful to decrease perioperative blood loss and facilitate total excision.

Performance of two Real-Time RT-PCR assays for quantitation of hepatitis C virus RNA: evaluation on HCV genotypes 1-4.

Accuracy for monitoring of the concentration of hepatitis C virus (HCV) RNA represents a major challenge throughout the management of patients with chronic hepatitis C. To investigate the genotype-independent efficiency and the accuracy of two real-time detection reverse transcription-polymerase chain reaction (RT-PCR) assays; the Cobas Ampliprep/Cobas TaqMan (CAP/CTM); and the Abbott RealTime HCV (ART), a total of 184 samples with different HCV subtypes were examined; 1b (n=58), 2a (n=39), 2b (n=26), 3a (n=20), and 4 (n=41). A robust linear correlation was observed between the two assays applied to genotypes 1b, 2a, 2b, and 3a [the correlation coefficient (R) ranged from 0.99 to 0.98], but not to genotype 4 specimens (R=0.78). A significant difference in measurements of HCV RNA using CAP/CTM and ART in serum samples with genotypes 1b and 4 was observed (0.72, -0.53 log IU/ml, P<0.0001, 0.01, respectively). A robust correlation was observed between the HCV core antigen and HCV RNA values by either of the HCV RNA quantitation assays applied to all genotypes with exception of genotype 4, for which R was higher with ART (R=0.95) than with CAP/CTM (R=0.80). The lower limit of detection of CAP/CTM and ART were 41.4 and 28.5 IU/ml using the WHO standards, respectively. In conclusion, two RT-PCR assays had a high efficiency and accuracy for quantitation of HCV RNA of genotypes 2a, 2b, and 3a, but the mean values of HCV RNA differed for genotype 1b and 4.