Anticancer Activity and Underlying Mechanism of Phytochemicals against Multiple Myeloma.

Multiple myeloma (MM)-a common hematologic malignancy of plasma cells-accounts for substantial mortality and morbidity rates. Due to the advent of novel therapies such as immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and monoclonal antibodies (mAbs), response rates were increased and free survival and overall survival have been elevated. However, adverse events including toxicity, neuropathy or continuous relapse are still problems. Thus, development of novel drugs which have less side effects and more effective is needed. This review aims to recapitulate the pharmacologic anti-MM mechanisms of various phytochemicals, elucidating their molecular targets. Keywords related to MM and natural products were searched in PUBMED/MEDLINE. Phytochemicals have been reported to display a variety of anti-MM activities, including apoptosis, cell cycle arrest, antiangiogenesis, and miRNA modulation. Some phytochemicals sensitize the conventional therapies such as dexamethasone. Also, there are clinical trials with phytochemicals such as agaricus, curcumin, and Neovastat regarding MM treatment. Taken together, this review elucidated and categorized the evidences that natural products and their bioactive compounds could be potent drugs in treating MM.

Enhanced Antioxidant Activity of Bioactives in Colored Grains by Nano-Carriers in Human Lens Epithelial Cells.

The use of phytochemicals for preventing chronic diseases associated with oxidative stress such as cataracts is hindered by their low bioavailability. The effects of nano-carriers on the antioxidant activities of extracts of black rice with giant embryo (BRGEx) and soybeans (SBx) have been determined in human lens epithelial B3 cells. Scanning (SEM) and transmission electron microscopy (TEM) demonstrated that rGO (reduced graphene oxide) has a flat surface unlike GO (graphene oxide), which has a distinctive wrinkled structure with defects. UPLC analysis revealed 41.9 µg/100 g of γ-oryzanols in water extract of BRGE, and 111.8 µg /100 g of lutein, 757.7 µg/100 g of γ-tocotrienol, 4071.4 µg/100 g of γ-tocopherol in 40% ethanol extract of soybeans, respectively. Even though a low concentration of BRGEx alone did not show any antioxidant activity in B3 cells, co-treatment of BRGEx with rGO together substantially reduced hydrogen peroxide and methylglyoxal-induced DNA damage, as determined by phosphorylated γH2AX. In addition, SBx with rGO also attenuated DNA damage. Furthermore, intracellular reactive oxygen species were significantly decreased by combining extracts of these colored grains with rGO. These results suggest a potential application of nanocarriers for enhancing the bioavailability of phytochemicals.

Connecting charge transfer kinetics to device parameters of a narrow-bandgap polymer-based solar cell.

To achieve intrinsically light-weight flexible photovoltaic devices, a bulk-heterojunction-type active layer with a narrow-bandgap polymer is still considered as one of the most important candidates. Therefore, detailed information about the charge transfer efficiency from a photo-excited species on an electron-donating polymer to an electron acceptor is an important factor, given that it is among the most fundamental quantitative measures to understand the solar power conversion efficiency, in particular at the initial stage followed by primary exciton formation. To obtain accurate information in this regard, wide-range acceptor concentration-dependent transient absorption spectroscopy with femtosecond laser pulse excitation was performed using a representative narrow-bandgap polymer, commonly known as PTB7. The investigated acceptor concentration range covered was from 0.01 wt% up to 10 wt%, in addition to a 0 wt% pristine polymer sample and a sample with a conventional acceptor concentration of 60 wt%, which is important for high efficiency. From the kinetic data, an almost two orders of magnitude faster acceptor-induced charge transfer rate constant in addition to the native primary exciton lifetime of about 100 picoseconds could be extracted. These data were used to verify the suggested kinetic model and compare with device properties that show no meaningful loss during the extraction of photo-generated charge carriers.

Transverse mode instability induced by stimulated Brillouin scattering in a pulsed single-frequency large-core fiber amplifier.

We report the observation of transverse mode instability (TMI) in a pulsed single-frequency ytterbium-doped large-core fiber amplifier in which stimulated Brillouin scattering (SBS) is generated easily owing to the high peak power and narrow linewidth of the laser pulses. It was shown experimentally that the threshold of TMI is almost the same as that of SBS and that the suppression of SBS also increases the threshold of TMI, which indicates that the TMI originates from SBS in the fiber.

Heat shock protein 27 phosphorylation is involved in epithelial cell apoptosis as well as epithelial migration during corneal epithelial wound healing.

We reported the expression of phosphorylated HSP27 during epithelial wound healing in murine corneas (Jain et al., 2012) in July of 2012. This in vivo investigation demonstrated that the expression levels of phosphorylated HSP27 were greater in wounded corneal epithelial cells than in unwounded controls and that the localization of phosphorylated HSP27 was in the basal and superficial epithelia three days following corneal epithelial wounding. We suggested that phosphorylated HSP27 had a role in the early phase of corneal epithelial wound healing. The purpose of this study was to investigate the exact role of heat shock protein 27 (HSP27) phosphorylation for the wound healing of cultured human corneal epithelial cells (HCECs). HSP27-specific siRNAs and control-siRNAs, with no known homologous targets in HCECs, were created. The cultured HCECs were divided into two groups: Scrambled control-siRNA-transfected group vs. HSP27-specific siRNA-transfected group. The scratch-induced directional wounding assay, Western blotting, using antibodies against non-phosphorylated and phosphorylated HSP27, non-phosphorylated and phosphorylated Akt, and Bcl-2-associated X protein (Bax), immunofluorescence staining to determine the filament actin, flow cytometry to measure apoptosis, and proliferation assay were performed to determine the role of HSP27. Western blot assay showed that the expression of phosphorylated HSP27 significantly increased at 5, 10, and 30 min after scratch wounding, compared with those in unwounded HCECs (all p < 0.05). Western blot assay also showed HSP27-specific siRNAs effectively blocked the expression of non-phosphorylated HSP27. The HSP27-specific siRNA-transfected group had more Bax expression, less phosphorylated Akt expression, and less non-phosphorylated and phosphorylated HSP27 expression (all p < 0.05). The scratch-induced directional wounding assay showed the HSP27-specific siRNA-transfected group with a less migrating cell number than the control-siRNA-transfected group (p < 0.05). Immunofluorescence staining showed that reorganization of actin cytoskeleton prominently decreased in the HSP27-specific siRNA-transfected group, compared with the control siRNA-tranfected group. Flow cytometry revealed that the HSP27-specific siRNA-transfected group had more HCEC apoptosis. Proliferation assay showed no difference between the two groups. In conclusion, the role of HSP27 in corneal epithelial wound healing can be epithelial cell apoptosis, as well as epithelial migration. HSP27 is involved in HCEC migration by the reorganization of actin cytoskeleton.

Bifidobacterium lactis IDCC 4301 (B. lactis Fit™) supplementation effects on body fat, serum triglyceride, and adipokine ratio in obese women: a randomized clinical trial.

Obesity is a common metabolic disease characterized by abnormal fat accumulation. It contributes to health issues, such as type 2 diabetes, cardiovascular disease, and dyslipidemia, necessitating continuous management through diet and physical activity. Probiotics, particularly Bifidobacterium lactis IDCC 4301 (B. lactis Fit™), have shown promise in positively regulating the gut microbiota. Therefore, this study aimed to evaluate the anti-obesity effect of B. lactis IDCC 4301 (B. lactis Fit™) in obese women. A randomized, double-blind, placebo-controlled, parallel-arm study was performed in 99 volunteers with a body mass index (BMI) of 25-30 kg m-2. The participants were randomly assigned to probiotics (n = 49, >5.0 × 109 CFU day-1) or placebo (n = 50) groups. Body fat, lipid profiles, and adipokine levels were assessed at baseline and at 12 weeks. After 12 weeks, changes in total fat (placebo -0.16 ± 0.83 kg; probiotics -0.45 ± 0.83 kg; p = 0.0407), trunk fat (placebo -0.03 ± 0.50 kg; probiotics -0.22 ± 0.51 kg; p = 0.0200), and serum triglyceride concentration (placebo 13 ± 60 mg dL-1; probiotics -15 ± 62 mg dL-1; p = 0.0088) were significantly different between the groups. The difference in total fat mass change between groups among postmenopausal women was greater than that of all women. A significant positive correlation was found between the change in total fat mass and log leptin/adiponectin ratio (R = 0.371, p = 0.0112) in the probiotics group. In addition, BMI (26.6 ± 1.9 kg m-2 to 26.4 ± 2.0 kg m-2, p = 0.0009) and leg fat (42 ± 5% to 41 ± 5%, p = 0.0006) significantly decreased in the probiotics group after 12 weeks, but there was no difference in the placebo group. In conclusion, B. lactis IDCC 4301 (B. lactis Fit™) may be associated with body fat loss through changes in metabolic health parameters, such as serum triglyceride and adipokine levels. The clinical trial registry number is KCT0007425 (https://cris.nih.go.kr).

Self-Mixed Biphasic Liquid Metal Composite with Ultra-High Stretchability and Strain-Insensitivity for Neuromorphic Circuits.

Neuromorphic circuits that can function under extreme deformations are important for various data-driven wearable and robotic applications. Herein, biphasic liquid metal particle (BMP) with unprecedented stretchability and strain-insensitivity (ΔR/R0 = 1.4@ 1200% strain) is developed to realize a stretchable neuromorphic circuit that mimics a spike-based biologic sensory system. The BMP consists of liquid metal particles (LMPs) and rigid liquid metal particles (RLMPs), which are homogeneously mixed via spontaneous solutal-Marangoni mixing flow during coating. This permits facile single step patterning directly on various substrates at room temperature. BMP is highly conductive (2.3 × 106 S/m) without any post activation steps. BMP interconnects are utilized for a sensory system, which is capable of distinguishing variations of biaxial strains with a spiking neural network, thus demonstrating their potential for various sensing and signal processing applications.

Bidirectional thermo-regulating hydrogel composite for autonomic thermal homeostasis.

Thermal homeostasis is an essential physiological function for preserving the optimal state of complex organs within the human body. Inspired by this function, here, we introduce an autonomous thermal homeostatic hydrogel that includes infrared wave reflecting and absorbing materials for improved heat trapping at low temperatures, and a porous structure for enhanced evaporative cooling at high temperatures. Moreover, an optimized auxetic pattern was designed as a heat valve to further amplify heat release at high temperatures. This homeostatic hydrogel provides effective bidirectional thermoregulation with deviations of 5.04 °C ± 0.55 °C and 5.85 °C ± 0.46 °C from the normal body temperature of 36.5 °C, when the external temperatures are 5 °C and 50 °C, respectively. The autonomous thermoregulatory characteristics of our hydrogel may provide a simple solution to people suffering from autonomic nervous system disorders and soft robotics that are susceptible to sudden temperature fluctuations.

Ultrathin Mixed Ionic-Electronic Conducting Interlayer via the Solution Shearing Technique for High-Performance Lithium-Sulfur Batteries.

The commercialization of lithium-sulfur (Li-S) batteries has been hampered by diverse challenges, including the shuttle phenomenon and low electrical/ionic conductivity of lithium sulfide and sulfur. To address these issues, extensive research has been devoted to developing multifunctional interlayers. However, interlayers capable of simultaneously suppressing the polysulfide (PS) shuttle and ensuring stable electrical and ionic conductivity are relatively uncommon. Moreover, the use of thick and heavy interlayers results in an unavoidable decline in the energy density of Li-S batteries. We developed an ultrathin (750 nm), lightweight (0.182 mg cm-2) interlayer that facilitates mixed ionic-electronic conduction using the solution shearing technique. The interlayer, composed of carbon nanotube (CNT)/Nafion/poly-3,4-ethylenedioxythiophene:tetracyanoborate (PEDOT:TCB), effectively suppresses the shuttle phenomenon through the synergistic segregation and adsorption effects on PSs by Nafion and CNT/PEDOT, respectively. Furthermore, the electrical/ionic conductivity of the interlayer can be improved via counterion exchange and homogeneous Li+ ion flux/good wettability from SO3- functional group of Nafion, respectively. Enhanced sulfur utilization and reaction kinetics through polysulfide shuttle inhibition and facilitated electron/ion transfer by interlayer enable a high discharge capacity of 1029 mA h g-1 in the Li-S pouch cell under a high sulfur loading of 5.3 mg cm-2 and low electrolyte/sulfur ratio of 5 µL mg-1.

Stamping transfer of a quantum dot interlayer for organic photovoltaic cells.

An organophilic cadmium selenide (CdSe) quantum dot (QD) interlayer was prepared on the active layer in organic solar cells by a stamping transfer method. The mother substrate composed of a UV-cured film on a polycarbonate film with strong solvent resistance makes it possible to spin-coat QDs on it and dry transfer onto an active layer without damaging the active layer. The QD interlayers have been optimized by controlling the concentration of the QD solution. The coverage of QD particles on the active layer was verified by TEM analysis and fluorescence images. After insertion of the QD interlayer between the active layer and metal cathode, the photovoltaic performances of the organic solar cell were clearly enhanced. By ultraviolet photoelectron spectroscopy of CdSe QDs, it can be anticipated that the CdSe QD interlayer reduces charge recombination by blocking the holes moving to the cathode from the active layer and facilitating efficient collection of the electrons from the active layer to the cathode.

Investigation of the Effect of 3D Meniscus Geometry on Fluid Dynamics and Crystallization via In Situ Optical Microscopy-Assisted Mathematical Modeling.

Solution-based thin-film solidification is a complex process involving various transport phenomena that are intricately dependent on multiple experimental parameters. The difficulty of analyzing this process experimentally or conducting exact numerical simulation make it challenging to understand, predict, and control the solidification process. In this work, a simple and effective technique to analyze the thin-film solidification process during solution shearing, based on 3D geometrical model of the meniscus, is proposed. The 3D meniscus geometry, which changes depending on the experimental parameters, is attained using high-speed side-view and top-view in situ microscopy. Thereafter, mass and momentum transport mathematical models are applied to obtain numerical solutions of transport phenomena within the meniscus. Utilizing these results, the underlying mechanism of dendritic growth of small molecule organic semiconductor is elucidated, which has previously been unknown. The 3D meniscus modeling is particularly important for this analysis, as dendrite formation is strongly dependent on the meniscus geometry near the contact line and mass transport variation perpendicular to the coating direction. This technique enables the study of complex relationship between experimental parameters and solidification process, which is widely applicable to various materials and coating systems; whereby, better understanding of thin-film growth and device performance optimization is possible.

Large-Area Synthesis of Ultrathin, Flexible, and Transparent Conductive Metal-Organic Framework Thin Films via a Microfluidic-Based Solution Shearing Process.

Iminosemiquinone-linker-based conductive metal-organic frameworks (c-MOFs) have attracted much attention as next-generation electronic materials due to their high electrical conductivity combined with high porosity. However, the utility of such c-MOFs in high-performance devices has been limited to date by the lack of high-quality MOF thin-film processing. Herein, a technique known as the microfluidic-assisted solution shearing combined with post-synthetic rapid crystallization (MASS-PRC) process is introduced to generate a high-quality, flexible, and transparent thin-film of Ni3 (hexaiminotriphenylene)2 (Ni3 (HITP)2 ) uniformly over a large-area in a high-throughput manner with thickness controllability down to tens of nanometers. The MASS-PRC process utilizes: 1) a micromixer-embedded blade to simultaneously mix and continuously supply the metal-ligand solution toward the drying front during solution shearing to generate an amorphous thin-film, followed by: 2) immersion in amine solution for rapid directional crystal growth. The as-synthesized c-MOF film has transparency of up to 88.8% and conductivity as high as 37.1 S cm-1 . The high uniformity in conductivity is confirmed over a 3500 mm2 area with an arithmetic mean roughness (Ra ) of 4.78 nm. The flexible thin-film demonstrates the highest level of transparency for Ni3 (HITP)2 and the highest hydrogen sulfide (H2 S) sensing performance (2,085% at 5 ppm) among c-MOFs-based H2 S sensors, enabling wearable gas-sensing applications.

BK002 Induces miR-192-5p-Mediated Apoptosis in Castration-Resistant Prostate Cancer Cells via Modulation of PI3K/CHOP.

BK002 consists of Achyranthes japonica Nakai (AJN) and Melandrium firmum Rohrbach (MFR) that have been used as herbal medicines in China and Korea. AJN and MFR have been reported to have anti-inflammatory, anti-oxidative, and anti-cancer activities, although the synergistic targeting multiple anti-cancer mechanism in castration-resistant prostate cancer (CRPC) has not been well reported. However, the drug resistance and transition to the androgen-independent state of prostate cancer contributing to CRPC is not well studied. Here, we reported that BK002 exerted cytotoxicity and apoptosis in CRPC PC3 cell lines and prostate cancer DU145 cell lines examined by cytotoxicity, western blot, a LIVE/DEAD cell imaging assay, reactive oxygen species (ROS) detection, quantitative real-time polymerase chain reaction (RT-PCR), and transfection assays. The results from our investigation found that BK002 showed more cellular cytotoxicity than AJN and MFR alone, suggesting that BK002 exhibited potential cytotoxic properties. Consistently, BK002 increased DNA damage, and activated p-γH2A.X and depletion of survivin-activated ubiquitination of pro-PARP, caspase9, and caspase3. Notably, live cell imaging using confocal microscopy found that BK002 effectively increased DNA-binding red fluorescent intensity in PC3 and DU145 cells. Also, BK002 increased the anti-proliferative effect with activation of the C/EBP homologous protein (CHOP) and significantly attenuated PI3K/AKT expression. Notably, BK002-treated cells increased ROS generation and co-treatment of N-Acetyl-L-cysteine (NAC), an ROS inhibitor, significantly preventing ROS production and cellular cytotoxicity, suggesting that ROS production is essential for initiating apoptosis in PC3 and DU145 cells. In addition, we found that BK002 significantly enhanced miR-192-5p expression, and co-treatment with BK002 and miR-192-5p inhibitor significantly reduced miR-192-5p expression and cellular viability in PC3 and DU145 cells, indicating modulation of miR-192-5p mediated apoptosis. Finally, we found that BK002-mediated CHOP upregulation and PI3K downregulation were significantly reduced and restrained by miR-192-5p inhibitor respectively, suggesting that the anti-cancer effect of BK002 is associated with the miR-192-5p/PI3K/CHOP pathway. Therefore, our study reveals that a combination of AJN and MFR might be more effective than single treatment against apoptotic activities of both CRPC cells and prostate cancer cells.

Generation of continuous-wave single-frequency 1.5 W 378 nm radiation by frequency doubling of a Ti:sapphire laser.

We have generated continuous-wave single-frequency 1.5 W 378 nm radiation by frequency doubling a high-power Ti:sapphire laser in an external enhancement cavity. An LBO crystal that is Brewster-cut and antireflection coated on both ends is used for a long-term stable frequency doubling. By optimizing the input coupler's reflectivity, we could generate 1.5 W 378 nm radiation from a 5 W 756 nm Ti:sapphire laser. According to our knowledge, this is the highest CW frequency-doubled power of a Ti:sapphire laser.

Retarding Ion Exchange between Conducting Polymers and Ionic Liquids for Printable Top Electrodes in Semitransparent Organic Solar Cells.

Semitransparent organic solar cells (ST-OSCs) are considered to be an influential tool for aesthetic and economic building-integrated photovoltaics, which can be fabricated by the printing technology. A poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) and ionic liquid (IL) composite has been considered as an electrode for ST-OSCs because of its high electrical conductivity, high transparency, and printability. However, we found that the introduction of IL into the PEDOT:PSS solution for enhancing its electrical conductivity results in (1) nonreliable printing of PEDOT:PSS/IL composite films because of gradual gelation of the mixture solution and (2) the production of chemically reactive ion pairs during ion exchange between PSS and IL, which induces the oxidation of the underlying organic semiconductors during printing. To solve these problems, we developed a sequential printing method using pristine PEDOT:PSS and IL solutions to retard ion exchange, thus preventing chemical doping of organic semiconductors by newly generated ion pairs. Finally, by using only solution processes, we demonstrate efficient ST-OSCs with a printed PEDOT:PSS/IL composite as the top electrode, exhibiting a power conversion efficiency of 6.32% at an average visible transmittance of 35.4%.

Protection against amyloid beta cytotoxicity by sulforaphane: role of the proteasome.

The 26S proteasome plays a major role in degradation of abnormal proteins within the cell. The indirect antioxidant including sulforaphane (SFN) protects cells from oxidative damage by increasing the expression of Nrf2-target genes. It has been observed that the expression of multiple subunits of the proteasome was up-regulated by indirect antioxidants through the Nrf2 pathway. In the current study, the role of SFN in amyloid beta(1-42) (Abeta(1-42))-induced cytotoxicity has been investigated in murine neuroblastoma cells. Treatment with SFN protected cells from Abeta(1-42)-mediated cell death in Neuro2A and N1E 115 cells. Inhibition of proteasome activities by MG132 could abolish the protective effect of SFN against Abeta(1-42). Neuro2A cells, which were stably overexpressing the catalytic subunit of the proteasome PSMB5, showed an elevated resistance toward Abeta(1-42) toxicity compared to control cells. Furthermore, the in vitro assay demonstrated that the Abeta(1-42) peptide is degraded by the proteasome fraction. These results suggest that proteasome-inducing indirect antioxidants may facilitate the removal of the Abeta(1-42) peptide and lead to the amelioration of abnormal protein-associated etiologies.

Periodicity of cerebral flow velocity during sleep and its association with white-matter hyperintensity volume.

Impaired sleep-related activation of the cerebral waste-clearance system might be related with the brain aging process. We hypothesized that cerebral blood-flow pattern changes during sleep might reflect the activation of the cerebral waste-clearance system and investigated its association with the cerebral white-matter hyperintensity (WMH) volume. Fifty healthy volunteers were prospectively recruited. In addition to the baseline transcranial Doppler parameters, the mean flow velocity (MFV) of the middle cerebral artery was monitored during waking and short-term non-REM sleep. Spectral density analysis was performed to analyze the periodic MFV variation patterns. For the aged subgroup (>50 years, n = 25), the WMH volumes in the total, subcortical, and periventricular regions were measured. The MFV periodic pattern during sleep was substantially augmented over that in the waking status. Spectral density analysis of MFV showed a noticeable peak in the very-low-frequency (VLF) band during sleep status (sleep/waking ratio 2.87 ± 2.71, P < 0.001). In linear regression analysis in the aged subgroup, the sleep/waking ratio of the VLF peak was inversely associated with total (P = 0.013) and subcortical (P = 0.020) WMH volumes. Sleep-related amplification of the cerebral flow-velocity periodicity might reflect the activation of cerebral waste clearance system during sleep, and be related to the pathogenesis of cerebral WMH.

Role of the Nrf2-antioxidant system in cytotoxicity mediated by anticancer cisplatin: implication to cancer cell resistance.

The treatment of alkylating cytotoxic drug cisplatin is often limited by high incidence rate of resistance. In the present study, the potential involvement of the transcription factor Nrf2 in determination of cisplatin cytotoxicity has been investigated. Nrf2-deficient murine embryonic fibroblasts showed increased cell death, cytotoxicity, and apoptosis in response to cisplatin treatment compared to wild-type cells. Cisplatin-resistant human ovarian cancer SK-OV cells, which are retaining 25-fold higher levels of GSH than murine fibroblasts, could be sensitized by inhibition of Nrf2. Transfection with Nrf2 siRNA into SK-OV cells resulted in severe degree of GSH depletion and exacerbated cytotoxicity following cisplatin treatment compared to scrambled RNA control. In conclusion, we propose that the Nrf2 pathway, which plays a protective role in normal cells, can be a potential target to control cancer cell resistance to oxidants, cytotoxic chemicals, and radiation.

External-cavity frequency doubling of a 5-W 756-nm injection-locked Ti:sapphire laser.

We have developed a 5-W 756-nm injection-locked Ti:sapphire laser and frequency-doubled it in an external enhancement cavity for the generation of watt-level 378-nm single-frequency radiation, which is essential for isotope-selective optical pumping of thallium atoms. With a lithium triborate (LBO) crystal in the enhancement cavity, 1.1 W at 378 nm was coupled out from the cavity. Such results are to our knowledge the highest powers of continuous-wave single-frequency radiation generated from a Ti:sapphire laser and its frequency doubling.

Thermoelectric Properties of Hot-Pressed Bi-Doped n-Type Polycrystalline SnSe.

ᅟ: We report on the successful preparation of Bi-doped n-type polycrystalline SnSe by hot-press method. We observed anisotropic transport properties due to the (h00) preferred orientation of grains along the pressing direction. The electrical conductivity perpendicular to the pressing direction is higher than that parallel to the pressing direction, 12.85 and 6.46 S cm-1 at 773 K for SnSe:Bi 8% sample, respectively, while thermal conductivity perpendicular to the pressing direction is higher than that parallel to the pressing direction, 0.81 and 0.60 W m-1 K-1 at 773 K for SnSe:Bi 8% sample, respectively. We observed a bipolar conducting mechanism in our samples leading to n- to p-type transition, whose transition temperature increases with Bi concentration. Our work addressed a possibility to dope polycrystalline SnSe by a hot-pressing process, which may be applied to module applications. HIGHLIGHTS: 1. We have successfully achieved Bi-doped n-type polycrystalline SnSe by the hot-press method. 2. We observed anisotropic transport properties due to the [h00] preferred orientation of grains along pressing direction. 3. We observed a bipolar conducting mechanism in our samples leading to n- to p-type transition.