Titanium Silicide: A Promising Candidate of Recombination Layer for Perovskite/Tunnel Oxide Passivated Contact Silicon Two-Terminal Tandem Solar Cells.

This study proposes a titanium silicide (TiSi2) recombination layer for perovskite/tunnel oxide passivated contact (TOPCon) 2-T tandem solar cells as an alternative to conventional transparent conductive oxide (TCO)-based recombination layers. TiSi2 was formed while TiO2 was made by oxidizing a Ti film deposited on the p+-Si layer. The reaction formation mechanism was proposed based on the diffusion theory supported by experimental results. The optical and electrical properties of the TiSi2 layer were optimized by controlling the initial Ti thicknesses (5-100 nm). With the initial Ti of 50 nm, the lowest reflectance and highly ohmic contact between the TiO2 and p+-Si layers with a contact resistivity of 161.48 mΩ·cm2 were obtained. In contrast, the TCO interlayer shows Schottky behavior with much higher contact resistivities. As the recombination layer of TiSi2 and the electron transport layer of TiO2 are formed simultaneously, the process steps become simpler. Finally, the MAPbI3/TOPCon tandem device yielded an efficiency of 16.23%, marking the first reported efficiency for a device including a silicide-based interlayer.

Alleviating depressive-like behavior in DSS-induced colitis mice: Exploring naringin and poncirin from Poncirus trifoliata extracts.

Patients with inflammatory bowel diseases (IBDs), including ulcerative colitis (UC) and Crohn's disease (CD), often have concomitant mental disorders such as depression and anxiety. Therefore, a bidirectional approach involving the gut and brain axes is necessary for the prevention and treatment thereof. In this study, we explored the potential of Poncirus trifoliata extract (PT), traditionally known for its neuroprotective effects against gastrointestinal diseases, as a natural treatment agent for IBD in a dextran sulfate sodium (DSS)-induced colitis model. Oral administration of PT ameliorated weight loss and inflammatory responses in mice with DSS-induced colitis. Furthermore, PT treatment effectively restored the colon length and ameliorated enterocyte death by inhibiting DSS-induced reactive oxygen species (ROS)-mediated necroptosis. The main bioactive components of PT, poncirin and naringin, confirmed using ultra-performance liquid chromatography-quadrupole time-of-flight (UPLC-qTOF), can be utilized to regulate necroptosis. The antidepressant-like effects of PT were confirmed using open field test (OFT) and tail suspension test (TST). PT treatment also restored vascular endothelial cell integrity in the hippocampus. In the Cornu Ammonis 1 (CA1) and dentate gyrus (DG) regions of the hippocampus, PT controlled the neuroinflammatory responses of proliferated microglia. In conclusion, PT, which contains high levels of poncirin and naringin, has potential as a bidirectional therapeutic agent that can simultaneously improve IBD-associated intestinal and mental disorders.

Bioprinting-Assisted Tissue Assembly for Structural and Functional Modulation of Engineered Heart Tissue Mimicking Left Ventricular Myocardial Fiber Orientation.

Left ventricular twist is influenced by the unique oriented structure of myocardial fibers. Replicating this intricate structural-functional relationship in an in vitro heart model remains challenging, mainly due to the difficulties in achieving a complex structure with synchrony between layers. This study introduces a novel approach through the utilization of bioprinting-assisted tissue assembly (BATA)-a synergistic integration of bioprinting and tissue assembly strategies. By flexibly manufacturing tissue modules and assembly platforms, BATA can create structures that traditional methods find difficult to achieve. This approach integrates engineered heart tissue (EHT) modules, each with intrinsic functional and structural characteristics, into a layered, multi-oriented tissue in a controlled manner. EHTs assembled in different orientations exhibit various contractile forces and electrical signal patterns. The BATA is capable of constructing complex myocardial fiber orientations within a chamber-like structure (MoCha). MoCha replicates the native cardiac architecture by exhibiting three layers and three alignment directions, and it reproduces the left ventricular twist by exhibiting synchronized contraction between layers and mimicking the native cardiac architecture. The potential of BATA extends to engineering tissues capable of constructing and functioning as complete organs on a large scale. This advancement holds the promise of realizing future organ-on-demand technology.

Melanophilin regulates dendritogenesis in melanocytes for feather pigmentation.

Limited studies using animal models with a few natural mutations in melanophilin (Mlph) provided partial functions of Mlph in melanosome trafficking. To investigate cellular functions of Mlph, especially ZnF motif of Mlph, we analyzed all three Mlph knockout (KO) quail lines, one and two base pair (bp) deletions as models for total KO, and three bp deletion causing deletion of one Cysteine (C84del) in the ZnF motif. All quail lines had diluted feather pigmentation with impaired dendritogenesis and melanosome transport in melanocytes. In vitro studies revealed capability of binding of the ZnF motif to PIP3, and impairment of PI3P binding and mislocalization of MLPH proteins with ZnF motif mutations. The shortened melanocyte dendrites by the C84del mutation were rescued by introducing WT Mlph in vitro. These results revealed the diluted feather pigmentation by Mlph mutations resulted from congregation of melanosomes in the cell bodies with impairment of the dendritogenesis and the transport of melanosomes to the cell periphery.

ELONGATED HYPOCOTYL 5 interacts with HISTONE DEACETYLASE 9 to suppress glucosinolate biosynthesis in Arabidopsis.

Glucosinolates (GSLs) are defensive secondary metabolites produced by Brassicaceae species in response to abiotic and biotic stresses. The biosynthesis of GSL compounds and the expression of GSL-related genes are highly modulated by endogenous signals (i.e., circadian clocks) and environmental cues, such as temperature, light, and pathogens. However, the detailed mechanism by which light signaling influences GSL metabolism remains poorly understood. In this study, we found that a light-signaling factor, ELONGATED HYPOCOTYL 5 (HY5), was involved in the regulation of GSL content under light conditions in Arabidopsis (Arabidopsis thaliana). In hy5-215 mutants, the transcript levels of GSL pathway genes were substantially upregulated compared with those in wild-type plants. The content of GSL compounds was also substantially increased in hy5-215 mutants, whereas 35S::HY5-GFP/hy5-215 transgenic lines exhibited comparable levels of GSL-related transcripts and GSL content to those in WT plants. HY5 physically interacts with HISTONE DEACETYLASE9 (HDA9) and binds to the proximal promoter region of MYB29 and IMD1 to suppress aliphatic GSL biosynthetic processes. These results demonstrate that HY5 suppresses GSL accumulation during the daytime, thus properly modulating GSL content daily in Arabidopsis plants.

Bisphenol Analogs Downregulate the Self-Renewal Potential of Spermatogonial Stem Cells.

PURPOSE: In this study, we investigated the effect of bisphenol-A (BPA) and its major analogs, bisphenol-F (BPF), and bisphenol-S (BPS), on spermatogonial stem cells (SSCs) populations using in vitro SSC culture and in vivo transplantation models. MATERIALS AND METHODS: SSCs enriched from 6- to 8-day-old C57BL/6-eGFP+ male mice testes were treated with varying concentrations of bisphenols for 7 days to examine bisphenol-derived cytotoxicity and changes in SSC characteristics. We utilized flow cytometry, immunocytochemistry, real-time quantitative reverse transcription-PCR, and western blot analysis. The functional alteration of SSCs was further investigated by examining donor SSC-derived spermatogenesis evaluation through in vivo transplantation and subsequent testis analysis. RESULTS: BPF exhibited a similar inhibitory effect on SSCs as BPA, demonstrating a significant decrease in SSC survival, inhibition of proliferation, and induction of apoptosis. On the other hand, while BPS was comparatively weaker than BPA and BPF, it still showed significant SSC cytotoxicity. Importantly, SSCs exposed to BPA, BPF, and BPS exhibited a significant reduction in donor SSC-derived germ cell colonies per total number of cultured cells, indicating that, like BPA, BPF, and BPS can induce a comparable reduction in functional SSCs in the recipient animals. However, the progress of spermatogenesis, as evidenced by histochemistry and the expressions of PCNA and SSC specific markers, collectively indicates that BPA, BPF, and BPS may not adversely affect the spermatogenesis. CONCLUSIONS: Our findings indicate that the major BPA substitutes, BPF and BPS, have significant cytotoxic effects on SSCs, similar to BPA. These effects may lead to a reduction in the functional self-renewal stem cell population and potential impacts on male fertility.

Post-polymerization of three-dimensional printing resin using a dental light curing unit.

Background/Purpose: In vat photopolymerization, post-polymerization of the three-dimensional (3D) printing resin is necessary to ensure the optimum physical properties of the printed objects. This study aimed to evaluate the potential use of a handheld polywave light-emitting diode (LED) dental light-curing unit (LCU) for post-polymerizing 3D printed resins by measuring the microhardness and biaxial flexural strength of the post-polymerized resin. Material and methods: 3D printed 1- and 2-mm-thick disks were irradiated with a dental LCU at 3200 mW/cm2. Post-polymerization was repeated either on one side from the top surface: two cycles (T2), four cycles (T4), and eight cycles (T8), or on both sides from the top and bottom surfaces: one cycle (T1B1), two cycles (T2B2), and four cycles (T4B4) for each side. The microhardness and biaxial strength of the disks were compared to those post-polymerized by a conventional desktop polymerizing unit (PC) and those without post-polymerization (NC). Results: Microhardness of the disks varied between the top and bottom surfaces of the 1-mm and 2-mm-thick disks, depending on the post-polymerization methods. T8 and T4B4 produced comparable microhardness on the top surface to PC for both thicknesses. In contrast, PC, T2B2, and T4B4 exhibited the highest microhardness on the bottom surface. Except for NC, the 1-mm-thick disks had a higher biaxial flexural strength than the 2-mm-thick disks. T4B4 resulted in the highest biaxial flexural strength for both thicknesses, which was comparable to that of the desktop polymerizing unit. Conclusion: The microhardness and biaxial flexural strengths of the post-polymerized 3D-printed disks increase with polymerization time. With sufficient polymerization from both sides, the polywave LCU has the potential to be a viable alternative to desktop polymerization units.

High energy density in artificial heterostructures through relaxation time modulation.

Electrostatic capacitors are foundational components of advanced electronics and high-power electrical systems owing to their ultrafast charging-discharging capability. Ferroelectric materials offer high maximum polarization, but high remnant polarization has hindered their effective deployment in energy storage applications. Previous methodologies have encountered problems because of the deteriorated crystallinity of the ferroelectric materials. We introduce an approach to control the relaxation time using two-dimensional (2D) materials while minimizing energy loss by using 2D/3D/2D heterostructures and preserving the crystallinity of ferroelectric 3D materials. Using this approach, we were able to achieve an energy density of 191.7 joules per cubic centimeter with an efficiency greater than 90%. This precise control over relaxation time holds promise for a wide array of applications and has the potential to accelerate the development of highly efficient energy storage systems.

Remote Epitaxy: Fundamentals, Challenges, and Opportunities.

Advanced heterogeneous integration technologies are pivotal for next-generation electronics. Single-crystalline materials are one of the key building blocks for heterogeneous integration, although it is challenging to produce and integrate these materials. Remote epitaxy is recently introduced as a solution for growing single-crystalline thin films that can be exfoliated from host wafers and then transferred onto foreign platforms. This technology has quickly gained attention, as it can be applied to a wide variety of materials and can realize new functionalities and novel application platforms. Nevertheless, remote epitaxy is a delicate process, and thus, successful execution of remote epitaxy is often challenging. Here, we elucidate the mechanisms of remote epitaxy, summarize recent breakthroughs, and discuss the challenges and solutions in the remote epitaxy of various material systems. We also provide a vision for the future of remote epitaxy for studying fundamental materials science, as well as for functional applications.

Correction to "Dual-Surfactant-Capped Ag Nanoparticles as a Highly Selective and Sensitive Colorimetric Sensor for Citrate Detection".

[This corrects the article DOI: 10.1021/acsomega.9b04199.].

Identification of vernalization-related genes and cold memory element (CME) required for vernalization response in radish (Raphanus sativus L.).

Floral transition is accelerated by exposure to long-term cold like winter in plants, which is called as vernalization. Acceleration of floral transition by vernalization is observed in a diversity of biennial and perennial plants including Brassicaceae family plants. Scientific efforts to understand molecular mechanism underlying vernalization-mediated floral transition have been intensively focused in model plant Arabidopsis thaliana. To get a better understanding on floral transition by vernalization in radish (Raphanus sativus L.), we investigated transcriptomic changes taking place during vernalization in radish. Thousands of genes were differentially regulated along time course of vernalization compared to non-vernalization (NV) sample. Twelve major clusters of DEGs were identified based on distinctive expression profiles during vernalization. Radish FLC homologs were shown to exert an inhibition of floral transition when transformed into Arabidopsis plants. In addition, DNA region containing RY motifs located within a Raphanus sativus FLC homolog, RsFLC1 was found to be required for repression of RsFLC1 by vernalization. Transgenic plants harboring disrupted RY motifs were impaired in the enrichment of H3K27me3 on RsFLC1 chromatin, thus resulting in the delayed flowering in Arabidopsis. Taken together, we report transcriptomic profiles of radish during vernalization and demonstrate the requirement of RY motif for vernalization-mediated repression of RsFLC homologs in radish (Raphanus sativus L.).

HNF4A guides the MLL4 complex to establish and maintain H3K4me1 at gene regulatory elements.

Hepatocyte nuclear factor 4A (HNF4A/NR2a1), a transcriptional regulator of hepatocyte identity, controls genes that are crucial for liver functions, primarily through binding to enhancers. In mammalian cells, active and primed enhancers are marked by monomethylation of histone 3 (H3) at lysine 4 (K4) (H3K4me1) in a cell type-specific manner. How this modification is established and maintained at enhancers in connection with transcription factors (TFs) remains unknown. Using analysis of genome-wide histone modifications, TF binding, chromatin accessibility and gene expression, we show that HNF4A is essential for an active chromatin state. Using HNF4A loss and gain of function experiments in vivo and in cell lines in vitro, we show that HNF4A affects H3K4me1, H3K27ac and chromatin accessibility, highlighting its contribution to the establishment and maintenance of a transcriptionally permissive epigenetic state. Mechanistically, HNF4A interacts with the mixed-lineage leukaemia 4 (MLL4) complex facilitating recruitment to HNF4A-bound regions. Our findings indicate that HNF4A enriches H3K4me1, H3K27ac and establishes chromatin opening at transcriptional regulatory regions.

Routine Ureteral Stenting in Kidney Transplant Reduces Postoperative Hydronephrosis and Percutaneous Ureteral Interventions: A Single-Center Experience.

OBJECTIVES: The effect of routine ureteral stenting on postoperative hydronephrosis and percutaneous ureteral intervention in kidney transplant remains unknown. This study aimed to evaluate the effects of routine ureteral stenting on hydronephrosis and percutaneous ureteral intervention and the cost benefit of ureteral stenting in kidney transplant. MATERIALS AND METHODS: We retrospectively analyzed patients who underwent kidney transplant at a tertiary institution between 2005 and 2021. We adopted a ureteral stentingprotocol in2017, anda comparisonwas performed with previous patients without stents. RESULTS: In total, 539 patients underwent kidney transplant(271 with stents [51.3%], 268 without stents [49.7%]). Hydronephrosis was detected in 16 cases (5.9%) and 30 cases (11.2%) of groups with and without stents,respectively (P = .041). Among patients with hydronephrosis, the number of patients who underwent percutaneous ureteral intervention was significantly lower in the stent group than in the nostent group (1 [6.25%] vs 10 [33.33%]; P= .014).Twenty patients (3.71%) experienced major urologic complications (19 [7.1%] in the no-stent group, and 1 [0.4%] in the stent group; P = .001). No significant differences between the groups were shown in the incidence of urinary tract infections within 3 months of transplant (24 [8.9%] vs 22 [8.2%]; P = .846). No differences were shown between the groups in ureterovesical anastomosis time (24.4 vs 24.03 min; P = .699) or 1-year graft survival (97% vs 97.8%; P = .803). The healthcare cost was significantly lower in the stent group than in the no-stent group by $1702.05 ($15000.89 vs $16702.95; P < .001). CONCLUSIONS: Routine ureteral stenting in kidney transplant significantly decreased the incidence of postoperative hydronephrosis and percutaneous ureteral intervention. Stenting did notlead to increased urinary tract infections and was cost-effective.

Unilateral Pediculectomy and Reduction with Short-Segment Pedicle Screw Fixation for Thoracolumbar Burst Fracture: A Case Series.

BACKGROUND: This study aimed to evaluate the efficacy of unilateral pediculectomy and reduction with short-segment pedicle screw fixation for thoracolumbar burst fracture. METHODS: We retrospectively reviewed patients who underwent a unilateral pediculectomy and reduction with short-segment fixation and interbody fusion for thoracolumbar burst fracture. The unilateral pediculectomy created sufficient space to approach the ventral side of the spinal cord for removing bone fragments and insertion of an interbody cage to correct kyphosis. Lumbar lordosis (LL), pelvic incidence (PI) minus LL, and segmental Cobb angle were measured at 3 time points: preoperatively, postoperatively, and final follow-up. Furthermore, sagittal vertical axis (SVA) was measured to assess global sagittal balance at the final follow-up. RESULTS: A total of 10 patients, with a mean age of 39.8 ± 21.0, underwent the surgical procedure. All patients had a thoracolumbar injury classification and severity score > 5. The mean follow-up period was 15.8 ± 13.9 months. The mean postoperative LL (46.0 ± 5.8) was significantly higher (P = 0.008) than the preoperative measurement (32.8 ± 8.2). The mean postoperative PI minus LL (2.2 ± 8.4) was not significantly lower (P = 0.051) than preoperative measurement (15.4 ± 12.6). The mean postoperative segmental Cobb angle (11.4 ± 8.4) was significantly higher (P < 0.001) than the preoperative measurement (-11.6 ± 10.9). At the final follow-up, the mean sagittal vertical axiswas 10.0 ± 28.8 mm. CONCLUSIONS: Unilateral pediculectomy and reduction with short-segment fixation and interbody fusion served as an efficient surgical method for thoracolumbar burst fracture.

Research Note: Muscle hypertrophy is associated with reversed sexual dimorphism in body size of quail.

Sexual dimorphism is phenotypic differences between males and females in the same species. In general, males in most animals are larger than females at the same age, however, in quail, females have a larger body size with greater muscle mass than males. To understand what characteristics in muscle growth play roles in reversed sexual dimorphism in quail, the weights and the characteristics of the pectoralis major and gastrocnemius muscles (PM and GM, respectively) of male and female quail were compared in the current study. The data showed that 15-wk-old female quail have significantly heavier bodies, and PM and GM weights compared to male quail (1.27-folds, 1.29-folds, and 1.16-folds, respectively). To compare muscle characteristics such as hypertrophy (increased size) and hyperplasia (increased cell number), the PM and GM were stained using hematoxylin and eosin, and then histological characteristics such as total cross-sectional area (CSA), number and size of myofibers, and muscle bundle of the muscles were measured and analyzed. In both PM and GM, there were no differences in total numbers of myofibers and muscle bundles as well as the average numbers of myofibers per bundle between sexes. However, the sizes of myofiber and the bundle were significantly increased in female compared to male (1.33-folds and 1.28-folds in PM, and both 1.23-folds in GM, respectively). The findings of the current study suggest that muscle hypertrophy in female quail, not hyperplasia, can be attributed to the sexual dimorphism in quail size.

Oxidation differences on Si- versus C-terminated surfaces of SiC during planarization in the fabrication of high-power, high-frequency semiconductor device.

Silicon carbide (SiC) wafers have attracted attention as a material for advanced power semiconductor device applications due to their high bandgap and stability at high temperatures and voltages. However, the inherent chemical and mechanical stability of SiC poses significant challenges in the chemical mechanical planarization (CMP) process, an essential step in reducing defects and improving surface flatness. SiC exhibits different mechanical and chemical properties depending on SiC terminal faces, affecting SiC oxidation behavior during the CMP process. Here, we investigate the process of oxide layer formation during the CMP process and how it relates to the SiC terminal faces. The results show that under the same conditions, the C-terminated face (C-face) exhibits higher oxidation reaction kinetics than the Si-terminated face (Si-face), forming an oxide layer of finer particles. Due to the different oxidation kinetic tendencies, the oxide layer formed on the C-face has a higher friction coefficient and more defects than the oxide layer formed on the Si-face. This results in a higher removal rate during CMP for the C-face than the Si-face. Furthermore, by controlling the physicochemical properties of the oxide film, high removal rates can be achieved by friction with the pad alone, without the need for nanoparticle abrasives.

Emulation Evaluation of Interior Beam-Column Connections in PC and RC Moment-Resisting Frames.

Precast concrete (PC) structures have many advantages, but their use in the construction of middle- to high-rise buildings is limited. The construction of PC structures requires skills in various operations such as transportation, assembly, lifting, and structural soundness. In particular, regarding the seismic design of PC structures, it is necessary to clearly evaluate whether they have the same structural performance and usability as integral RC (cast-in-place) structures. In this paper, an experimental study was conducted to investigate whether PC members can achieve a seismic performance equivalent to that of RC members in beam-column joints, which are representative moment-resisting frames. The main variables are the two types of structural systems (intermediate and special moment-resisting frames) and the design flexural strength ratio of the columns and beams. The experimental and analytical results showed that the seismic performance of the PC specimens was equivalent to that of the RC specimens in terms of strength, stiffness, energy dissipation, and strain distribution, except for the specimen with splice sleeve bond failure of the column reinforcement (poor filling of the internal mortar). In addition, the I series satisfied the present emulation evaluation criteria for special moment-resisting frames of PC structures, confirming the possibility of applying intermediate moment-resisting frames.

Thiobarbiturate-Derived Compound MHY1025 Alleviates Renal Fibrosis by Modulating Oxidative Stress, Epithelial Inflammation, and Fibroblast Activation.

Chronic kidney disease (CKD) is a kidney structure and function abnormality. CKD development and progression are strongly influenced by oxidative stress and inflammatory responses, which can lead to tubulointerstitial fibrosis. Unfortunately, there are no effective or specific treatments for CKD. We investigated the potential of the thiobarbiturate-derived compound MHY1025 to alleviate CKD by reducing oxidative stress and inflammatory responses. In vitro experiments using NRK52E renal tubular epithelial cells revealed that MHY1025 significantly reduced LPS-induced oxidative stress and inhibited the activation of the NF-κB pathway, which is involved in inflammatory responses. Furthermore, treatment with MHY1025 significantly suppressed the expression of fibrosis-related genes and proteins induced by TGFß in NRK49F fibroblasts. Furthermore, we analyzed the MHY1025 effects in vivo. To induce kidney fibrosis, mice were administered 250 mg/kg folic acid (FA) and orally treated with MHY1025 (0.5 mg/kg/day) for one week. MHY1025 effectively decreased the FA-induced inflammatory response in the kidneys. The group treated with MHY1025 exhibited a significant reduction in cytokine and chemokine expression and decreased immune cell marker expression. Decreased inflammatory response was associated with decreased tubulointerstitial fibrosis. Overall, MHY1025 alleviated renal fibrosis by directly modulating renal epithelial inflammation and fibroblast activation, suggesting that MHY1025 has the potential to be a therapeutic agent for CKD.

Concurrent laparoscopic highly selective vagotomy with closure of duodenal ulcer perforations show good clinical results as primary repair alone.

OBJECTIVE: To compare clinical and operative results between laparoscopic primary repair (LPR) alone and LPR with highly selective vagotomy (LPR-HSV) in patients with duodenal ulcer perforation. METHODS: Clinical data from patients who underwent either LPR or LPR-HSV by resecting both sides of the neurovascular bundle using an ultrasonic or bipolar electrosurgical device for duodenal ulcer perforations, between 2010 and 2020, were retrospectively collected. Between-group differences in continuous and categorical variables were statistically analysed. RESULTS: Data from 184 patients (mean age, 49.6 years), who underwent either LPR (n = 132) or LPR-HSV (n = 52) were included. The mean operation time was significantly longer in the LPR-HSV group (116.5 ± 39.8 min) than in the LPR group (91.2 ± 33.3 min). Hospital stay was significantly shorter in the LPR-HSV group (8.6 ± 2.6 days) versus the LPR group (11.3 ± 7.1 days). The mean postoperative day of starting soft fluid diet was also significantly shorter in the LPR-HSV group (4.5 ± 1.4 days) than in the LPR group (5.6 ± 4 days). No between-group difference in morbidity rate was observed. The learning curve of the HSV procedure showed a stable procedure time after 10 operations. CONCLUSIONS: LPR with HSV may be a safe and feasible procedure for selective cases who are at high risk for ulcer recurrence.

Greater numbers and sizes of muscle bundles in the breast and leg muscles of broilers compared to layer chickens.

Meat-type (broiler) and egg-type (layer) chickens were bred by intensive selection over the years, resulting in more numbers and larger sizes of myofibers. Although the characteristics are important parameters in muscle growth and meat quality, muscle bundle characteristics have not been studied in poultry. Therefore, this study aimed to compare the histological characteristics of myofibers and muscle bundles in muscles between male broiler (Ross broiler breed) chickens and layer (Hy-Line) chickens. Chicken muscles, pectoralis major (PM) and gastrocnemius (GM), were sampled at the age of 49 days and stained to analyze histological characteristics. Expectedly, body weights (BWs) and weights of PM and GM muscles in 49-day-old broilers were significantly heavier than those in layers. Within PM, broilers exhibited greater number and cross-sectional area (CSA) of myofibers than layers (3.3- and 3.3-fold, respectively). The total number and CSA of PM muscle bundles were approximately 1.5 and 6.6 times greater, respectively, in broilers than layers. Moreover, broilers exhibited 2 times greater number of myofibers per bundle of PM muscle than layers. Within GM, myofiber number and CSA were 2.3- and 2.4-fold greater, respectively, in broilers than layers. In addition, the total number of muscle bundles and bundle CSA were 2.5- and 2.1-fold greater, respectively, in broilers than in the layers. The novel findings of the current study provide evidence that greater muscle mass of broilers occurs by both hyperplasia and hypertrophy of muscle bundles and myofibers.