Parallel Pattern Research Articles

Massively Parallel High-Throughput Single-Cell Patterning and Large Biomolecular Delivery in Mammalian Cells Using Light Pulses.

The recent advancements of single-cell analysis have significantly enhanced the ability to understand cellular physiology when compared to bulk cellular analysis. Here a massively parallel single-cell patterning and very large biomolecular delivery is reported. Micro-pillar polydimethyl siloxane stamp with different diameters (40-100µm with 1cm × 1cm patterning area) is fabricated and then imprint distinct proteins and finally pattern single-cell to small clusters of cells depending on the micro-pillar diameters. The maximum patterning efficiency is achieved 99.7% for SiHa, 96.75% for L929, and 98.6% for MG63 cells, for the 100µm micro-pillar stamp. For intracellular delivery of biomolecules into the patterned cells, a titanium micro-dish device is aligned on top of the cells and exposed by infrared light pulses. The platform successfully delivers small to very large biomolecules such as PI dyes (668Da), dextran 3000Da, siRNA (20-24bp), and large size enzymes (464KDa) in SiHa, L929 and MG63 cells. The delivery efficiency for PI dye, Dextran 3000, siRNA, and enzyme for patterned cells are ≈95 ± 3%, 97 ± 1%, 96 ± 1% and 94 ± 3%, with cell viability of 98 ± 1%. Thus, the platform is compact, robust, easy for printing, and potentially applicable for single-cell therapy and diagnostics.

Speckle suppression in arbitrary parallel holographic illumination by the spatial frequency regaining method.

This Letter proposes a spatial frequency regaining method for parallel holographic illumination (SFR-PHI) to suppress speckle noise in phase-only computer-generated holography (CGH). Based on the accurate calculation of the beam bandwidth, this method uses the bandwidth-limited quadratic initial phase and weighted constraint iteration to generate the optimized phase hologram, which can provide the accurate spatial frequency of multiple illumination patterns. The results show that SFR-PHI performs superiorly in speckle suppression for generating dozens of illumination patterns in parallel and with arbitrary shapes and numbers. Compared with other speckle-suppression methods, it exhibits significant advantages in terms of accuracy and modulation efficiency.

Numerical Evaluation of the Flow within a Rhomboid Tessellated Pipe Network with a 3 × 3 Allometric Branch Pattern for the Inlet and Outlet

This study presents a comprehensive assessment of the hydrodynamic performance of a novel pipe network with tessellated geometry and allometric scales. Numerical simulations were used to evaluate flow behaviour and pressure drop. The comparison geometry featured a Parallel Pipe Pattern (PPP), while the proposed design employed a Rhombic Tessellation Pattern (RTP). Steady-state simulations were conducted under identical boundary conditions, examining water mass flows ranging from 0.01 to 0.06 kg/s. The results revealed RTP significant advantages over the PPP. The RTP, integrated with a fractal tree pattern, demonstrated remarkable capabilities in achieving uniform flow distribution and maintaining laminar flow regimes across the mass flow rates. Additionally, exhibited an average reduction in pressure drop of 92% resulting in improved efficiency. The Reynolds number at PPP inlet was 5.4 times higher than in the RTP, explaining the considerably higher pressure drop. At a mass flow rate of 0.06 kg/s, the PPP experienced a pressure drop of up to 3.43 kPa, while the RTP’s pressure drop was only 0.350 kPa, highlighting a remarkable decrease of 91.5%. These findings underscore the RTP superior performance in minimizing pressure drop, making it suitable for accommodating higher mass flow rates, thus highlighting its exceptional engineering potential.

The Morphology-Controllable Synthesis of Ni–Co–O Nanosheets on a 3D Porous Ni Template as a Binder-Free Electrode for a Solid-State Symmetric Supercapacitor

In this work, a porous Ni template (Ni–Co–O@3D Ni) with Ni–Co oxide nanosheets (Ni–Co–O)@3D was synthesized by incorporating Ni–Co oxide nanosheets within a 3D porous Ni template as a binder-free electrode for a supercapacitor. The 3D Ni template was synthesized with hydrogen bubble templates that possessed different applied voltages that marked differences in terms of physicochemical properties, as well as factors that affect the subsequent growth of Ni–Co–O nanosheets. Then, Ni and Co metal ion sources were introduced to produce the morphology adjustment of Ni–Co–O@3D Ni with a multiple hierarchical architecture with a hydrothermal process. Field emission scanning electron microscopy (FESEM), X-ray absorption spectroscopy (XAS), and an electrochemical analysis were employed to investigate the morphological, structural, and electrochemical characteristics. FESEM and XAS results evidenced that Ni–Co–O@3D Ni consists of a 3D, well-designed hierarchical interconnected network, and the local electronic structure change has a great influence on the capacitive performance. The electrochemical results of Ni–Co–O@3D Ni displayed an excellent electrochemical performance due to the synergistic effect of Ni and Co on Ni–Co–O@3D Ni, which possessed multiple oxidation states to enable various reversible Faradaic redox reactions. Remarkably, the solid-state symmetric supercapacitor fabricated with Ni–Co–O@3D Ni exhibited excellent capacitive behaviour at a wide operating voltage window and cycling performance. Also, the as-assembled solid-state symmetric supercapacitor (two devices in series) can successfully illuminate a desired parallel pattern consisting of 36 red LED lights, demonstrating its practical application as a supercapacitor.

Parallel Bootstrap-Based On-Policy Deep Reinforcement Learning for Continuous Fluid Flow Control Applications

The coupling of deep reinforcement learning to numerical flow control problems has recently received considerable attention, leading to groundbreaking results and opening new perspectives for the domain. Due to the usually high computational cost of fluid dynamics solvers, the use of parallel environments during the learning process represents an essential ingredient to attain efficient control in a reasonable time. Yet, most of the deep reinforcement learning literature for flow control relies on on-policy algorithms, for which the massively parallel transition collection may break theoretical assumptions and lead to suboptimal control models. To overcome this issue, we propose a parallelism pattern relying on partial-trajectory buffers terminated by a return bootstrapping step, allowing a flexible use of parallel environments while preserving the on-policiness of the updates. This approach is illustrated on a CPU-intensive continuous flow control problem from the literature.

Investigation of osteogenesis and angiogenesis in perfusion bioreactors using improved multi-layer PCL-nHA-nZnO electrospun scaffolds.

Bone tissue engineering aims to create a three-dimensional, matured, angiogenic scaffold with a suitable thickness that resembles a natural bone matrix. On the other hand, electrospun fibers, which researchers have considered due to their good biomimetic properties, are considered 2D structures. Due to the highly interwovennetwork and small pore size, achieving the desired thickness for bone lesions has always been challenging. In bone tissue engineering, bioreactors are crucial for achieving initial tissue maturity and introducing certain signals as flow parameters for differentiation. In the present study, Human bone marrow mesenchymal stem cells (hBMSCs) and human umbilical vein endothelial cells (HUVECs) were co-cultured in a perfusion bioreactor on treated (improved pore size by gelatin sacrification and subsequent ultrasonication) 5-layer polycaprolactone-nano hydroxyapatite-nano zinc oxide (T-PHZ) scaffolds to investigate osteogenesis and angiogenesis simultaneously. The flow parameters and stresses on the cells were studied using two patterns of parallel and vertical scaffolds relative to the flow of the culture medium. In dynamic vertical flow (DVF), the culture medium flows perpendicular to the scaffolds, and in dynamic parallel flow (DPF), the culture medium flows parallel to the scaffolds. In allevaluations, static samples (S) served as the control group. Live/dead, and MTT assays demonstrated the biocompatibility of the 5-layer scaffolds and the suitability of the bioreactor's functional conditions. ALP activity, EDAX analysis, and calcium content measurements exhibited greater osteogenesis for T-PHZ scaffolds in DVF conditions. Calcium content increased by a factor of 2.2, 1.8, and 1.6 during days 7 to 14 of culture under DVF, DPF and S conditions, respectively. After 21days of co-culturing, an immunohistochemistry (IHC) test was performed to investigate angiogenesis and osteogenesis. Five antibodies were investigated in DVF, CD31, VEGFA, and VEGFR2 for angiogenesis, osteocalcin, and RUNX2 for osteogenesis. Compressive stress applied in DVF mode has increased osteogenic activity compared to DPF. The results indicated the development of ideal systems for osteogenesis and angiogenesis on the treated multilayer electrospun scaffolds in the perfusion bioreactor.

In-depth analysis on parallel processing patterns for high-performance Dataframes

The Data Science domain has expanded monumentally in both research and industry communities during the past decade, predominantly owing to the Big Data revolution. Artificial Intelligence (AI) and Machine Learning (ML) are bringing more complexities to data engineering applications, which are now integrated into data processing pipelines to process terabytes of data. Typically, a significant amount of time is spent on data preprocessing in these pipelines, and hence improving its efficiency directly impacts the overall pipeline performance. The community has recently embraced the concept of Dataframes as the de-facto data structure for data representation and manipulation. However, the most widely used serial Dataframes today (R, pandas) experience performance limitations while working on even moderately large data sets. We believe that there is plenty of room for improvement by taking a look at this problem from a high-performance computing point of view. In a prior publication, we presented a set of parallel processing patterns for distributed dataframe operators and the reference runtime implementation, Cylon [1]. In this paper, we are expanding on the initial concept by introducing a cost model for evaluating the said patterns. Furthermore, we evaluate the performance of Cylon on the ORNL Summit supercomputer.

Fracture patterns formed by tearing adhesive thin films from curved surfaces

It has been reported that tearing adhesive thin films from smooth developable surfaces can produce various fracture patterns, which can be either convergent or divergent. We experimentally show that the parallel one can be realized from a properly undulating surface. Then, we demonstrate that the formation of all the discovered patterns is governed by a unified rule, where the local geometry near the crack tip matters. Our theory can provide a master curve, universally capturing distinct crack behaviors in experiments. And diverse observed fracture patterns become predictable. Based on the unified perspective, we reveal that the stability of a parallel pattern is decided by the local concavity of the surface near the crack tips. In addition, this rule also applies to the tearing from nondevelopable surfaces, such as tearing the fruit skin from the pulp with a wide initial flap width. Finally, we suggest that such predictable tearing can be harnessed for controlled fragmentation of thin films and used for characterizing the mechanical properties of a film-substrate system where the substrate can own nonzero curvature.

Parallel anagenetic patterns in endemic Artemisia species from three Macaronesian archipelagos.

Anagenetic speciation is an important mode of evolution in oceanic islands, yet relatively understudied compared to adaptive radiation. In the Macaronesian region, three closely related species of Artemisia (i.e. A. argentea, A. thuscula and A. gorgonum) are each endemic from a single archipelago (i.e. Madeira, Canary Islands and Cape Verde, respectively), representing a perfect opportunity to study three similar but independent anagenetic speciation processes. By analysing plastid and nuclear DNA sequences, as well as nuclear DNA amount data, generated from a comprehensive sampling in all the islands and archipelagos where these species are currently distributed, we intend to find common evolutionary patterns that help us explain the limited taxonomic diversification experienced by endemic Macaronesian Artemisia. Our time-calibrated phylogenetic reconstruction suggested that divergence among the three lineages occurred in a coincidental short period of time during the Pleistocene. Haplotype and genetic differentiation analyses showed similar diversity values among A. argentea, A. thuscula and A. gorgonum. Clear phylogeographic patterns-showing comparable genetic structuring among groups of islands-were also found within the three archipelagos. Even from the cytogenetic point of view, the three species presented similarly lower genome size values compared to the mainland closely related species A. arborescens. We hypothesize that the limited speciation experienced by the endemic Artemisia in Madeira, Canary Islands and Cape Verde archipelagos could be related to their recent parallel evolutionary histories as independent lineages, combined with certain shared characteristics of seed dispersal, pollen transport and type of habitat.

Metastatic pattern of ovarian cancer delineated by tracing the evolution of mitochondrial DNA mutations

Ovarian cancer (OC) is the most lethal gynecologic tumor and is characterized by a high rate of metastasis. Challenges in accurately delineating the metastatic pattern have greatly restricted the improvement of treatment in OC patients. An increasing number of studies have leveraged mitochondrial DNA (mtDNA) mutations as efficient lineage-tracing markers of tumor clonality. We applied multiregional sampling and high-depth mtDNA sequencing to determine the metastatic patterns in advanced-stage OC patients. Somatic mtDNA mutations were profiled from a total of 195 primary and 200 metastatic tumor tissue samples from 35 OC patients. Our results revealed remarkable sample-level and patient-level heterogeneity. In addition, distinct mtDNA mutational patterns were observed between primary and metastatic OC tissues. Further analysis identified the different mutational spectra between shared and private mutations among primary and metastatic OC tissues. Analysis of the clonality index calculated based on mtDNA mutations supported a monoclonal tumor origin in 14 of 16 patients with bilateral ovarian cancers. Notably, mtDNA-based spatial phylogenetic analysis revealed distinct patterns of OC metastasis, in which a linear metastatic pattern exhibited a low degree of mtDNA mutation heterogeneity and a short evolutionary distance, whereas a parallel metastatic pattern showed the opposite trend. Moreover, a mtDNA-based tumor evolutionary score (MTEs) related to different metastatic patterns was defined. Our data showed that patients with different MTESs responded differently to combined debulking surgery and chemotherapy. Finally, we observed that tumor-derived mtDNA mutations were more likely to be detected in ascitic fluid than in plasma samples. Our study presents an explicit view of the OC metastatic pattern, which sheds light on efficient treatment for OC patients.

Performance evaluation of surface texturing on carbide tool under minimum quantity lubrication turning of aluminium alloy Al6061 using canola oil

Turning operation is considered an important material removal process and its performance depends largely on the machining parameters. This study presents the analysis of the effect of surface texturing on tool during MQL turning of Aluminium alloy Al6061 using canola oil. Minimum quantity lubrication possesses the benefits of flood lubrication as well as dry machining. Canola oil used in this study possesses good lubrication properties and its kinematic viscosity is 41 mm2/s at 40 °C. Tool texturing is in growing trend in the manufacturing industry and it has gained the attention of many researchers in the past few years. In this study parallel textured pattern is used in which the grooves are perpendicular to chip flow direction. Average surface roughness (Ra) and tangential cutting forces (Ft) are the responses measured. Chip patterns are also examined under different conditions. It is concluded that high spindle speed of 160 m/min along with low feeding rate of 0.2 mm/rev with MQL system using textured tool generates better results for tangential cutting force as well as average surface roughness in contrast with other machining conditions.

Modeling the influence of coolant flow directions on thermal performance of PEM fuel cell cooling plates with serpentine and straight flow channels

The flow direction of the coolant in cooling channels relative to the reactant gasses is critical for thermal performance. Here, four different flow patterns for the serpentine channel and three different flow patterns for the straight channel are numerically studied based on index of uniform temperature (IUT), maximum temperature, and pressure drop. For the serpentine flow channel, the left-cross pattern has the lowest index of uniform temperature and maximum temperature, while the right-cross pattern has the highest. The parallel and left-cross patterns exhibits best and worst performances, respectively, in terms of cooling performance for the straight channel. Nearly the same pressure drops are obtained for all flow patterns of both channel configurations. When the parallel pattern is used instead of the counter pattern in the straight channel and the left-cross pattern is used instead of the right-cross pattern in the serpentine channel, the IUT improves by 55.45% and 27.39%, respectively.

Is there link between hypoxemia severity and impaired functional connectivity? electrophysiological evidence from patients with obstructive sleep apnea syndrome

AbstractBackgroundApneas occur more than 30 times per hour in severe obstructive sleep apnea syndrome (OSAS) patients. Each apnea results in decrease of oxygen saturation that leads to recurring intermittent hypoxemia (IH). IH was suggested as a possible factor to contribute cognitive impairment in OSAS. In the present study, we aimed to investigate the functional connectivity in low and high hypoxemia OSAS sub‐groups.MethodThe study included 56 severe OSAS patients and age‐, gender‐ and education matched 33 healthy controls (HC). The OSAS group was divided into two subgroups according to their minimum SO2 level: low‐hypoxemia OSAS (SO2 dropped never below 80%, LHO, n = 29) and high‐hypoxemia OSAS (SO2 dropped below 80%, HHO, n = 27). All participants underwent detailed neuropsychological testing and an EEG recording, using auditory classical oddball paradigm. Imaginary coherency (ICOH) was calculated for intra‐hemispheric, inter‐hemispheric and midline electrode pairs in delta, theta, alpha, beta, and gamma frequency bands.ResultLHO patients did not differ from HC in any frequency band. HHO patients showed reduced intra hemispheric ICOH values at delta, theta and beta frequency bands compared to LHO patients. HHO patients also showed decreased intra hemispheric ICOH values at theta, alpha and beta frequency bands compered to HC. Inter hemispheric group differences were found at beta band indicating decreased ICOH values in HHO patients compared to LHO patients. Midline gamma ICOH values decreased in HHO patients compared to both HC and LHO patients. HHO patients showed decreased memory scores compared to both HC and LHO groups and decreased attention scores compared only to HC.ConclusionAs far as we know, this is the first study to investigate event‐related ICOH changes in OSAS. Above results indicates that decreased connectivity in OSAS may be due to increased IH. Patients with low levels of hypoxemia did not differ from healthy controls, yet patients with high hypoxemia showed diffuse functional connectivity changes. Coherency measures revealed a parallel pattern with the neuropsychological tests underpinning the adverse effect of IH on cognitive functions. Considering OSAS as a modifiable risk factor for developing Alzheimer’s disease, treatment methods to prevent intermittent hypoxemia (i.e., positive airway pressure treatment) gains additional importance.

T-FSM: A Task-Based System for Massively Parallel Frequent Subgraph Pattern Mining from a Big Graph

Finding frequent subgraph patterns in a big graph is an important problem with many applications such as classifying chemical compounds and building indexes to speed up graph queries. Since this problem is NP-hard, some recent parallel systems have been developed to accelerate the mining. However, they often have a huge memory cost, very long running time, suboptimal load balancing, and possibly inaccurate results. In this paper, we propose an efficient system called T-FSM for parallel mining of frequent subgraph patterns in a big graph. T-FSM adopts a novel task-based execution engine design to ensure high concurrency, bounded memory consumption, and effective load balancing. It also supports a new anti-monotonic frequentness measure called Fraction-Score, which is more accurate than the widely used MNI measure. Our experiments show that T-FSM is orders of magnitude faster than SOTA systems for frequent subgraph pattern mining. Our system code has been released at https://github.com/lyuheng/T-FSM.

Acral Melanocytic Nevi in a High-Risk Population: Prevalence, Clinical Characteristics and Dermatoscopic Patterns

Background: The prevalence of acral nevi and their dermatoscopic patterns have been mainly studied in Asian populations. Few data exist on the prevalence and clinico-dermatoscopic morphology of acral nevi in white populations. Objectives: The aim of this study was to assess the prevalence of acral nevi and evaluate their features in a cohort of Caucasian individuals at high risk for skin cancer. Methods: We prospectively examined the palms and soles of 680 high-risk patients who underwent total body clinical and dermatoscopic documentation, as a part of their routine follow-up, between January 2016 and March 2020 at a skin cancer referral center in Greece. Results: Overall, 334 acral lesions were detected in 217 (37.0%) of 585 patients in the study. The presence of acral nevi was associated with 2.6 higher odds of a total nevus count higher than 50 (OR: 2.6, p < 0.05, confidence intervals [CI]: 1.11–6.09). Of 334 acral nevi, 65.0% were clinically flat and 35.0% were clinically palpable. Palpable lesion had 19-fold higher probability of being located on the sole (OR: 19.44, p < 0.05, CI: 3.91–96.7). The parallel furrow pattern was present in 147 lesions (44.0%). In 76 lesions (22.8%), we observed a previously undefined pattern consisting of wavy lines, which was correlated with clinically palpable lesions (p < 0.001). The third most common pattern was homogeneous (10.5%), followed by the fibrillar (8.7%), the lattice-like (7.2%), the reticular (3.6%), and globular (3.3%). Conclusion: We observed a higher prevalence of benign acral melanocytic lesions than expected, probably related to our cohort selection of patients at high risk for developing skin cancer. Our study confirms the previously described dermatoscopic patterns and provides novel insights into the dermatoscopic morphology of acral palpable nevi, for which we described a new benign pattern consisting of wavy lines.

Experimental Study of Mass Transfer in a Plug Regime of Immiscible Liquid–Liquid Flow in a T-Shaped Microchannel

In the presented work, the influence of parameters such as the total flow rate of phases, the ratio of flow rates, and residence time on mass transfer during the two-phase flow of immiscible liquids in a T-shaped microchannel was investigated using the micro-LIF technique. The study focused on the plug flow regime, where a 70% water–glycerol solution was used as the dispersed phase, and tri-n-butyl phosphate (TBP) was used as the carrier phase. We determined the transition boundary between the dispersed and parallel flow patterns and calculated the plug length and velocities to develop a mass transfer model. Furthermore, we measured the partition coefficient for the set of liquids used in the experiments and analyzed the concentration fields inside the slugs of the continuous phase at various distances downstream of the T-junction. Using the obtained data, we determined the extraction efficiency and overall volumetric mass transfer coefficient and established dependencies demonstrating the effect of the flow-rate ratio, total flow rate, and the residence time on mass transfer rate and extraction efficiency. Finally, we developed a model for the overall volumetric mass transfer coefficient corresponding to the set of liquids used with an R-squared value of 0.966.

Distinct trajectories of caregiver-toddler physiological attunement during routine vaccinations.

Toddlers rely on their caregivers for regulatory support when faced with pain-related distress. The caregiver's ability to support their toddler relies on their capacity to regulate their own distress and respond effectively to the child's need for support. The aim of the current study was to describe patterns of caregiver-toddler physiological co-regulatory patterns, also known as attunement, during routine vaccinations across the second year of life. Caregiver-toddler dyads (N = 189) were part of a longitudinal cohort observed at either 12-, 18-, or 24-month well-baby vaccinations. Parallel-process growth-mixture modeling was used to examine patterns of dyadic physiological co-regulatory responses, indexed by high-frequency heart rate variability (HF-HRV). Three groups of dyads were discerned. The largest group (approximately 80%) demonstrated physiological attunement, with a stable and parallel regulatory pattern of HF-HRV from baseline to postneedle. The second group (7.9%) had parallel regulatory trajectories but with notably lower (ie, less regulated) HF-HRV values, which indicates independent regulatory responses (ie, a lack of attunement among dyad members). The third group (11.1%) showed diverging regulatory trajectories: Caregivers showed a stable regulatory trajectory, but toddlers demonstrated a steep decrease followed by an increase in HF-HRV values that surpassed their baseline levels by the third minute postneedle. Post hoc analyses with the HF-HRV groupings explored heart rate patterns and potential predictors. These findings elucidate potential adaptive and maladaptive co-regulatory parasympathetic patterns in an acute pain context.

Investigation of Teacher Candidates' Awareness towards Inclusive Education

This study aimed to examine the awareness of teacher candidates towards inclusive education. This mixed method study was performed with the convergent parallel mixed pattern. The sample of quantitative part of the study consisted of 708 teacher candidates in an education faculty determined by criterion sampling. The study group of the qualitative part of the research is 14 teacher candidates (preservice teachers) selected from among these participants. The research data were collected with Awareness Scale for Inclusive Education and Interview Form for Evaluation of Inclusive Education Course. The scale data were analyzed by descriptive and inferential statistics, and the semi-structured interview data were analyzed by content analysis. The results revealed that the awareness of teacher candidates’ inclusive education was at a moderate level. In addition, the awareness level of the participants who had inclusive education training was higher than the participants who did not, and the female participants had higher awareness compared to the male participants. The interview results revealed that training on inclusive education increased teacher candidates’ awareness of its history, aims, the students it encompasses, and its applications. According to the results of the research, it has been suggested to expand the inclusive education provided to teachers before and during the service.

Design of central symmetric lattice structure for ocean engineering based on fluid-solid-interaction

Some structures that constitute underwater vehicles and other ocean engineering structures, such as the shell of underwater vehicles, shafting of power systems, compressor impellers and propeller hubs, all have central symmetric or rotationally symmetric cross sections. In this paper, a kind of central symmetric lattice is designed. The lightweight design of the above structure with this lattice can significantly reduce the weight of the structure on the premise of reducing the static response of the structure. Combined with the ANSYS Parameter Design Language (APDL), the homogenization method is used to analyze the static response of the rotationally symmetric lattice structure and the parallel pattern lattice structure under pressure. The fluid load (pressure) of impeller is calculated by CFX. The results show that the structural stress of the central symmetric lattice structures with the same volume fraction is smaller than that of parallel pattern lattice under the same load when the rotationally symmetric structures have the same form. The application of the homogenization method proves that the above conclusions also improve the efficiency of the static response calculation of the central symmetric lattice structure. The design and research methods in this paper provide technical support for the realization of lightweight design of small and medium-sized underwater rotationally symmetric structures.

The Trajectories of Hepato-Biliary Indices Following Exposure to SARS-CoV-2

<i>Background</i>: The impact of SARS-CoV-2 on the hepato-biliary system is conflicting within the existing literature. Previous studies on the subject have mostly been documented among Caucasians using retrospectively-acquired data from patients with several confounding variables. Hence, the current study evaluated the trajectories of hepato-biliary biochemical indices among SARS-CoV-2-infected Nigerians who had no background confounding factors. <i>Methods</i>: This was a prospectively-designed longitudinal study conducted within Southern Nigeria among patients with RT-PCR-confirmed mild SARS-CoV-2 infection. All eligible participants were serially monitored/followed up before, during, and after mild SARS-CoV-2 infection using clinical/laboratory parameters to determine the impact of the virus on the hepato-biliary system. Specimen acquisition, laboratory workflow, and data management were all carried out using standardized protocols. <i>Results</i>: Among 152 studied, 46.1% had mild SARS-CoV-2 infection 5–10 days (Mean=7.5; SD:=2.19) after exposure with male predominance. Cough, malaise, and loss of taste/smell were the most predominant clinical manifestations among the confirmed mild cases. During the follow-up period, an increasing trend of hepato-biliary indices of the cholestatic pattern (with only total bilirubin and GGT reaching statistically significant threshold) in parallel with inflammatory markers (CRP, di-dimer and the neutrophil to lymphocyte ratio) was observed between 2-12 days following mild SARS-CoV-2 infection. However, no relationship was established between these cholestatic and inflammatory markers among the mild SARS-CoV-2-infected patients (p>0.05). <i>Conclusion</i>: Mild SARS-CoV-2 infection is associated with altered hepato-biliary biochemical indices of cholestatic pattern independent of SARS-CoV-2-induced inflammatory events. Incorporating hepato-biliary assessment during the initial evaluation and the use of non-hepatotoxic therapeutics during treatment is highly recommended.