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Patients with triple-negative breast cancer (TNBC) often develop metastases in visceral organs including the liver, but the detailed molecular mechanisms of TNBC liver metastasis is not clearly understood. In this study, we tried to dissect the process of pre-metastatic niche formation in the liver by using patient-derived xenograft (PDX) models of TNBC with different metastatic propensity. RNA sequencing of TNBC PDX models that successfully metastasized to liver showed upregulation of the Cx3cr1 gene in the liver microenvironment. In syngeneic breast cancer models, the Cx3cr1 upregulation in liver preceded the development of cancer cell metastasis and was the result of recruitment of CX3CR1-expressing macrophages. The recruitment was induced by the CX3CL1 production from the liver endothelial cells and this CX3CL1–CX3CR1 signaling in the pre-metastatic niche resulted in upregulation of MMP9 that promoted macrophage migration and cancer cell invasion. In addition, our data suggest that the extracellular vesicles derived from the breast cancer cells induced the TNFα expression in liver, which leads to the CX3CL1 upregulation. Lastly, the plasma CX3CL1 levels in 155 patients with breast cancer were significantly associated with development of liver metastasis. Implications: Our data provides previously unknown cascades regarding the molecular education of pre-metastatic niche in liver for TNBC.

Background Triple negative breast cancer (TNBC) is a breast cancer subtype with increased risk of distant metastasis, especially to lung and liver. In addition to the intrinsic characteristics of tumor cells, the molecular features of the tumor microenvironment cells can also regulate the metastasis process of TNBC. In this study, we tried to characterize the transcriptomic features of microenvironment fibroblasts associated with the distant metastasis of TNBC. Method We established PDX models by obtaining tumor tissues from 26 triple-negative breast cancer patients and transplanting them into the mammary fat pads of immunodeficient mice. When the PDX tumors grew sufficiently in the fat pads, we excised them and saved the mice to assess whether each PDX tumor was capable of developing spontaneous distant metastasis. We used bulk RNA sequencing and single cell RNA sequencing to determine the transcriptomic features associated with the distant metastasis. Results We classified the 26 TNBC PDX models based on their in vivo metastasis capacity and the clinical outcomes of the corresponding patients. Non-metastatic PDX models were defined as the lack of developing distant metastasis in either mouse experiment or clinical follow-up data (n=5). PDX models were defined as metastatic models when they developed distant metastasis in both mouse and human (n=4). We performed single cell RNA sequencing using the nine PDX tumors and observed a substantial gene expression differences of fibroblasts in the tumor microenvironment between the metastatic and non-metastatic PDX models. The fibroblasts of the metastatic PDX models showed up-regulation of genes involved in the response to hypoxia, inflammatory response, neutrophil chemotaxis, cellular response to IL-1, positive regulation of cell proliferation, and negative regulation of apoptotic process. Moreover, this difference of gene expression between metastatic and non-metastatic TNBC PDX models were not identified by the bulk RNA sequencing data. Conclusion By using the single cell RNA sequencing using the TNBC PDX models, we identified key features of fibroblasts in the tumor microenvironment that contributes to the metastasis capacity of TNBC. Further studies are on-going to elucidate the underlying mechanisms. Citation Format: Woo Hang Heo, Woochan Lee, SONGBIN LI, Jong-Il Kim, Hyeong-Gon Moon. The relationship between the gene expression difference of fibroblasts in the tumor microenvironment and metastasis of triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-21-06.

Background Malignant phyllodes tumour (MPT) is a rare breast malignancy with epithelial and mesenchymal features. Currently, there are no appropriate research models or effective targeted therapeutic approaches for MPT. Methods We collected fresh frozen tissues from nine patients with MPT and performed whole-exome and RNA sequencing. Additionally, we established patient-derived xenograft (PDX) models from patients with MPT and tested the efficacy of targeting dysregulated pathways in MPT using the PDX model from one MPT. Results MPT has unique molecular characteristics when compared to breast cancers of epithelial origin and can be classified into two groups. The PDX model derived from one patient with MPT showed that the mouse epithelial component increased during tumour growth. Moreover, targeted inhibition of platelet-derived growth factor receptor (PDGFR) and phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) by imatinib mesylate and PKI-587 showed in vivo tumour suppression effects. Conclusions This study revealed the molecular profiles of MPT that can lead to molecular classification and potential targeted therapy, and suggested that the MPT PDX model can be a useful tool for studying the pathogenesis of fibroepithelial neoplasms and for preclinical drug screening to find new therapeutic strategies for MPT.

Supplementary Table 1. Information about patients derived xenograft models and derived patient. Supplementary Table 2. Ontology of differentially expressed genes in metastasis-harboring liver of PDX models. Supplementary Table 3. Differentially expressed genes in liver and lung of metastasis-harboring PDX models. Supplementary Table 4. Human ratio in lung and liver of additional PDX models identified by RNA sequencing. Supplementary Table 5. Gene ontology of co-expressed genes with Cx3cr1 in liver of PDX models identified by RNA sequencing. Supplementary Table 6. Top ranked genes having significant correlation with Cx3cr1 in liver of PDX models identified by RNA sequencing. Supplementary Table 7. Demographic and clinical characteristics of all patients. Supplementary Table 8. Information about used primer sequences for quantitative real-time PCR Supplementary Figure 1. Liver and lung H&E staining pictures of eight nonmetastatic PDX models a. Microscopic images of non-metastasis harboring PDX mouse model's liver (left) and lung (right) taken at 400x magnification. Supplementary Figure 2. Immunohistochemistry about CX3CR1 in liver and lung of breast cancer metastasis patients. Supplementary Figure 3. Hepatic metastasis after four weeks after orthotopic injection of 4T1 breast cancer cells identified by H&E staining. Supplementary Figure 4. Identification of pre-metastatic niche in liver tissues of 4T1 bearing mice a. mRNA expression of inflammation associated genes identified by real-time PCR in liver tissues of 4T1 bearing mice. Supplementary Figure 5. Identification of CX3CR1 positive cell population. Supplementary Figure 6. FACS analysis with anti-CX3CR1 of Raw264.7 macrophage cell lines. Supplementary Figure 7. Trans-well migration assay of BMDM with or without CX3CL1. Supplementary Figure 8. Mmp9 mRNA expression having significant correlation with Cx3cr1 mRNA expression in liver of PDX models. Supplementary Figure 9. MMP9 expression of macrophages with CX3CL1 treatment. Supplementary Figure 10. Signaling pathway of CX3CL1 treated macrophages. Supplementary Figure 11. Splenic injection of 4T1 cells inducing hepatic metastasis within two weeks in most cases. Supplementary Figure 12. mRNA expression about Cx3cr1 and Mmp9 in liver of vehicle or AZD8797 treated BALB/C mice identified by real-time PCR. Supplementary Figure 13. Correlation plot of Tnfa and Cx3cr1 mRNA expression in liver and lung of PDX models. Supplementary Figure 14. EVs isolation of CD63-mRuby-4T1.

Boron-based compounds exhibiting a multiresonance thermally activated delayed fluorescence are regarded promising as a narrowband blue emitter desired for efficient displays with wide color gamut. However, their planar nature makes them prone to concentration-induced excimer formation that broadens the emission spectrum, making it hard to increase the emitter concentration without raising CIE y coordinate. To overcome this bottleneck, we here propose o -Tol-ν-DABNA-Me, wherein sterically hindered peripheral phenyl groups are introduced to reduce intermolecular interactions, leading to excimer formation and thus making the pure narrowband emission character far less sensitive to concentration. With this approach, we demonstrate deep-blue OLEDs with y of 0.12 and full width at half maximum of 18 nm, with maximum external quantum efficiency (EQE) of ca. 33%. Adopting a hyperfluorescent architecture, the OLED performance is further enhanced to EQE of 35.4%, with mitigated efficiency roll-off, illustrating the immense potential of the proposed method for energy-efficient deep-blue OLEDs.

We present an in-depth single cell atlas of in vitro multi-culture systems on human primary airway epithelium derived from normal and diseased lungs of 27 individual donors. Our large-scale single cell profiling identifies new cell states and differentiation trajectories of rare airway epithelial cell types in human distal lungs. By integrating single cell datasets of human lung tissues, we discover immune primed subsets enriched in lungs and organoids derived from patients with chronic respiratory disease. To demonstrate the full potential of our platform, we further illustrate transcriptomic responses to various respiratory virus infections in in vitro airway models. Our work constitutes a single-cell roadmap for the cellular and molecular characteristics of human primary lung cells in vitro and their relevance to human tissues in vivo.

Vertical sleeve gastrectomy (VSG) is the most commonly performed bariatric/metabolic surgery, exhibiting a high rate of diabetes remission in humans. To elucidate the molecular mechanisms of VSG, we performed transcriptomic analysis of the liver, fat, and muscle in VSG mice. C57BL/6 mice fed a high-fat diet were randomly assigned to sham or VSG surgery. The sham-operated mice were fed ad libitum (sham group) or pair-fed (sham-PF group) matching their food intake to the VSG-operated mice. Comparative transcriptomic analysis of the liver, fat, and muscle using RNA sequencing was performed. VSG reduced body weight and improved glucose tolerance compared to the sham group, but not more than the sham-PF group. Improvement in fatty liver and adipose tissue inflammation was comparable between VSG and sham-PF. However, global gene expression profiles showed distinctive changes in the liver, fat, and muscle of the VSG group compared to both the sham or sham-PF groups. The liver showed the most prominent gene expression changes. Immune response-related pathways were commonly upregulated in the three organs of the VSG group compared to the sham or sham-PF. VSG induces organ-specific gene expression changes in the liver, fat, and muscle, which may play critical roles in metabolic improvements after VSG.

The tumor microenvironment (TME), which the cancer is known to remodel, can interact with cancer in various ways, such as promoting or hindering metastasis. The challenge with comprehending TME is that each patient's individual variance makes it difficult to carry out a consistent analysis. We used the PDX model to analyze the alterations entirely brought about by cancer cells of each patient in the same environment exclusively. In 121 breast cancer patients, we created a PDX model and performed WES and RNA-seq. We repeatedly performed metastatic induction tests on the models of 26 TNBC patients among the PDX models we generated. The replicated experiments confirmed that cancer cells with frequent metastasis usually spread well, while cancer cells with seldom metastases rarely metastasize. For each of the five samples that had the greatest and worst rates of metastasis, the pre-metastatic xenograft tumor was analyzed using scRNA-seq. Metastasis could not be predicted by only cancer cells because there was no difference between the two groups. Still, fibroblasts and macrophages had distinct gene markers before metastasis which can predict metastasis. To explore TME that develops pre-metastatic niches (PMN) in organs that would be metastasis targets, we developed a metastatic model using 4T1 cell lines. Daily lung macrophage RNA-seq, lung WES, and lung scRNA-seq procedures were carried out for four weeks to examine the precise timing of metastasis and the daily changes in the transcriptome. Surprisingly, a few days before the presence of any cancer cells, the gene expression of lung macrophages had already undergone significant modification. Additionally, only injections of tumor-conditioned media that mimicked metastasis could activate PMN in lung macrophages. Citation Format: Woochan Lee, Hyewon Chung, Woohang Heo, Hyeong-Gon Moon, Seung Hyeok Seok, Jong-Il Kim. Identify features of fibroblast and macrophage which regulate metastasis of triple-negative breast cancer [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B019.

The demand for realistic haptic feedback actuators has increased as mobile devices have increased in popularity. However, most current haptic actuators provide limited 1-DOF tactile sensations, such as vibrations. This paper presents a 2-DOF haptic impact actuator that can provide planar directional (e.g., x and y directional) and magnitude tactile cues to a user. We built an impact actuator that was designed to be of such a size that a user can grasp it with one hand. Multiple electromagnets of the actuator drive a permanent magnet to hit the actuator housing, creating an impact. For the control of the impact direction, we assumed the direction of a magnetic field vector at the centre of the actuator would follow that of a reference vector formed by voltage heading into the electromagnet array. The results of magnetic field measurements support our assumption by showing that the trend of the magnetic field vector coincided with that of the reference voltage vector. Furthermore, the measurement of the impact acceleration showed the trend that the impact direction follows the reference voltage vector.

Gastric cancer (GC) is commonly treated by chemotherapy using 5-fluorouracil (5-FU) derivatives and platinum combination, but predictive biomarker remains lacking. We develop patient-derived xenografts (PDXs) from 31 GC patients and treat with a combination of 5-FU and oxaliplatin, to determine biomarkers associated with responsiveness. When the PDXs are defined as either responders or non-responders according to tumor volume change after treatment, the responsiveness of PDXs is significantly consistent with the respective clinical outcomes of the patients. An integrative genomic and transcriptomic analysis of PDXs reveals that pathways associated with cell-to-cell and cell-to-extracellular matrix interactions enriched among the non-responders in both cancer cells and the tumor microenvironment (TME). We develop a 30-gene prediction model to determine the responsiveness to 5-FU and oxaliplatin-based chemotherapy and confirm the significant poor survival outcomes among cases classified as non-responder-like in three independent GC cohorts. Our study may inform clinical decision-making when designing treatment strategies., Gastric cancer is commonly treated by chemotherapy using 5-fluorouracil derivatives and platinum combination, but predictive biomarker remains lacking. Here, the authors develop a 30-gene prediction model to determine the responsiveness to 5-fluorouracil and oxaliplatin-based chemotherapy through the integrative profiling of patient-derived xenografts

Background Although single-cell RNA sequencing of xenograft samples has been widely used, no comprehensive bioinformatics pipeline is available for human and mouse mixed single-cell analyses. Considering the numerous homologous genes across the human and mouse genomes, misalignment errors should be evaluated, and a new algorithm is required. We assessed the extents and effects of misalignment errors and exonic multi-mapping events when using human and mouse combined reference data and developed a new bioinformatics pipeline with expression-based species deconvolution to minimize errors. We also evaluated false-positive signals presumed to originate from ambient RNA of the other species and address the importance to computationally remove them. Result Error when using combined reference account for an average of 0.78% of total reads, but such reads were concentrated to few genes that were greatly affected. Human and mouse mixed single-cell data, analyzed using our pipeline, clustered well with unmixed data and showed higher k-nearest-neighbor batch effect test and Local Inverse Simpson’s Index scores than those derived from Cell Ranger (10 × Genomics). We also applied our pipeline to multispecies multisample single-cell library containing breast cancer xenograft tissue and successfully identified all samples using genomic array and expression. Moreover, diverse cell types in the tumor microenvironment were well captured. Conclusion We present our bioinformatics pipeline for mixed human and mouse single-cell data, which can also be applied to pooled libraries to obtain cost-effective single-cell data. We also address misalignment, multi-mapping error, and ambient RNA as a major consideration points when analyzing multispecies single-cell data.

This paper proposes a wireless power transfer (WPT) system by placing repeater coils to transfer power to multiple loads for the internet of things (IoT) devices and sensors in smart grid applications. The proposed system intermediate resonators (repeaters) not only function as power relays to enhance the transfer distance but also supplies power to its load attached to them. Equal power distribution and load-independent characteristics were obtained without efficiency degradation when any one of the loads was changed during system operation. Identical high-quality factor coils were designed using Litz-wire to reduce the skin effect. The coil size was 15.5 cm × 15.5 cm and the four relays achieved total efficiency of 51.7%, delivering 2 W power and output voltage of 5 V to each load with a total power transfer distance of 62 cm.

We propose a novel wearable robotic glove or exo-glove design scalable to the variation of the hand kinematics. While most of the traditional robot hand is driven by rotating the joint directly with a rigid body, our exo-glove deforms a robotic finger's skin and, thus, the hand skeleton joints. Multiple tendons woven on the exo-glove's surface can make multi-DOF finger joint motions. We allocated tendons to mimic a hand's intrinsic and extrinsic muscles. Thus, a robotic hand actuated with the exo-glove can perform natural finger motions, including abduction/adduction and flexion/extension of finger joints. Moreover, additional tendons for the thumb enable power grips and the robotic hand's human-like motion. The proposed design approach places all the actuators on the surface without directly actuating any of the hand skeleton's joint. Therefore, a random hand skeleton can work as a robotic hand by putting the wearable robotic glove on it. Thus, the proposed model provides a high degree of freedom on choosing hand skeletons. We expect the aforementioned biomimetic features of our proposed method will benefit not only traditional robotic hands design but also the design of prosthetic hands and robot power-assisted hand glove.

Haptic interface technologies for virtual reality applica have been developed to increase the reality and manipulability of a virtual object by creating a diverse tactile sensation. Most evaluation of the haptic technologies, however, have been limited to the haptic perception of the tactile stimuli via static virtual objects. Noting this, we investigated the effect of lateral cutaneous feedback, along with kinesthetic feedback on the perception of virtual object weight during manipulation. We modeled the physical interaction between a participant's finger avatars and virtual objects. The haptic stimuli were rendered with custom-built haptic feedback systems that can provide kinesthetic and lateral cutaneous feedback to the participant. We conducted two virtual object manipulation experiments, 1. a virtual object manipulation with one finger, and 2. the pull-out and lift-up of a virtual object grasped with a precision grip. The results of Experiment 1 indicate that the participants felt the virtual object rendered with lateral cutaneous feedback significantly heavier than with only kinesthetic feedback (p 0.05 for m

A dual-impedance operation, where coil impedance is controlled by operating frequency selection, is proposed to maintain optimum reflected impedance across coupling variation. More specifically, this work focuses on how high coupling between coils presents excessively high reflected resistance to transmitter (Tx) inverters, degrading the efficiency and output power of the inverter. To overcome this problem, the proposed system is equipped with dual-impedance coil and selects high- or low-impedance coil based on the ability to operate both at 200 kHz and 6.78 MHz frequencies. The reactive impedances of 6.78 MHz coils are designed to be higher than that of 200 kHz coils. Since the reflected resistance is proportional to the coil impedances and coupling squared, at close distance with high coupling coefficient, 200 kHz coils with low coil impedances are activated to prevent an excessive rise in reflected resistance. On the other hand, at large distance spacing with low coupling coefficient, 6.78 MHz coils with high coil impedances are activated so that sufficient reflected resistance is obtained even under the small coupling. The proposed system’s advantages are the high efficiency and the elimination of bulky mechanical relay switches. Measured efficiencies are 88.6–50% across 10 coupling variations.

Haptic interface technologies for virtual reality applications have been developed to increase the reality and manipulability of a virtual object by creating a diverse tactile sensation. Most evaluation of the haptic technologies, however, have been limited to the haptic perception of the tactile stimuli via static virtual objects. Noting this, we investigated the effect of lateral cutaneous feedback, along with kinesthetic feedback on the perception of virtual object weight during manipulation. We modeled the physical interaction between a participant’s finger avatars and virtual objects. The haptic stimuli were rendered with custom-built haptic feedback systems that can provide kinesthetic and lateral cutaneous feedback to the participant. We conducted two virtual object manipulation experiments, 1. a virtual object manipulation with one finger, and 2. the pull-out and lift-up of a virtual object grasped with a precision grip. The results of Experiment 1 indicate that the participants felt the virtual object rendered with lateral cutaneous feedback significantly heavier than with only kinesthetic feedback (p mref = 100 and 200 g). Similarly, the participants of Experiment 2 felt the virtual objects significantly heavier when lateral cutaneous feedback was available (p mref = 100, 200, and 300 g). Therefore, the additional lateral cutaneous feedback to the force feedback led the participants to feel the virtual object heavier than without the cutaneous feedback. The results also indicate that the contact force applied to a virtual object during manipulation can be a function of the perceived object weight (p = 0.005 for Experiment 1 and p = 0.02 for Experiment 2).

It is inevitable for data collection that IoT sensors are distributed to interested areas. However, not only the proper placement of sensors, but also the replacement of sensors that have run out of energy is very difficult. As a remedy, wireless charging systems for IoT sensors have been researched recently, but it is apparent that the availability of charging system is limited especially for IoT sensors scattered in rugged terrain. Thus, it is important that the sensor relocation models to recover sensing holes employ energy-efficient scheme. While there are various methods in the mobile model of wireless sensors, well-known wheel-based movements in rough areas are hard to achieve. Thus, research is ongoing in various areas of the hopping mobile model in which wireless sensors jump. Many past studies about hopping sensor relocation assume that all sensor nodes are aware of entire network information throughout the network. These assumptions do not fit well to the actual environment, and they are nothing but classical theoretical research. In addition, the physical environment (sand, mud, etc.) of the area in which the sensor is deployed can change from time to time. In this paper, we overcome the theoretical-based problems of the past researches and propose a new realistic hopping sensor relocation protocol considering terrain conditions. Since the status of obstacles around the sensing hole is unknown, the success rate of the hopping sensor relocation is used to predict the condition of the surrounding environment. Also, we are confident that our team is uniquely implementing OMNeT++ (Objective Modular Network Testbed in C++) simulation in the hopping sensor relocation protocol to reflect the actual communication environment. Simulations have been performed on various obstacles for performance evaluation and analysis, and we are confident that better energy efficiency with later appearance of sensing holes can be achieved compared to well-known relocation protocols.

A new method for making an explicit time-domain finite-element method unconditionally stable is developed for general electromagnetic analysis, where the dielectrics and conductors can be inhomogeneous, lossless, or lossy. In this method, for a given time step, we find the unstable modes that are the root cause of instability, and deduct them directly from the system matrix resulting from a time-domain finite-element based analysis. The resultant explicit time-domain simulation is absolutely stable for the given time step no matter how large it is, and irrespective of the space step. The accuracy of the method is also guaranteed when the time step is chosen based on accuracy. In addition to a formulation for lossless problems, formulations for general lossy problems are also presented in detail. Numerical experiments have demonstrated the accuracy, efficiency, and unconditional stability of the proposed new explicit method.

Diffuse intrinsic pontine glioma (DIPG) is one of the most lethal childhood brain tumors. This tumor is unique because it is detected exclusively in the ventral pons of patients aged between 6 and 7 years, which suggests a developmental nature of its formation. Signal transducer and activator of transcription 3 (STAT3) is a critical molecule for the differentiation of neural stem cells into astrocytes during neurodevelopment. Additionally, STAT3 is associated with oncogenesis and the epithelial-mesenchymal transition (EMT) in various types of tumor. In recent years, several studies have demonstrated the oncogenic role of STAT3 in high-grade gliomas. However, the role of STAT3 in DIPG at the cellular level remains unknown. To assess the possible association between gliogenesis and DIPG, the expression levels of various molecules participating in the differentiation of neural stem cells were compared between normal brain control tissues and DIPG tissues using open public data. All of the screened genes exhibited significantly increased expression in DIPG tissues compared with normal tissues. As STAT3 expression was the most increased, the effect of STAT3 inhibition in a DIPG cell line was assessed via STAT3 short hairpin (sh)RNA transfection and treatment with AG490, a STAT3 inhibitor. Changes in viability, apoptosis, EMT and radiation therapy efficiency were also evaluated. Downregulation of STAT3 resulted in decreased cyclin D1 expression and cell viability, migration and invasion. Additionally, treatment with STAT3 shRNA or AG490 suppressed the EMT phenotype. Finally, when radiation was administered in combination with STAT3 inhibition, the therapeutic efficiency, assessed by cell viability and DNA damage repair, was increased. The present results suggest that STAT3 is a potential therapeutic target in DIPG, especially when combined with radiation therapy.

The maintenance of genetic integrity is critical for stem cells to ensure homeostasis and regeneration. Little is known about how adult stem cells respond to irreversible DNA damage, resulting in loss of regeneration in humans. Here, we establish a permanent regeneration loss model using cycling human hair follicles treated with alkylating agents: busulfan followed by cyclophosphamide. We uncover the underlying mechanisms by which hair follicle stem cells (HFSCs) lose their pool. In contrast to immediate destructive changes in rapidly proliferating hair matrix cells, quiescent HFSCs show unexpected massive proliferation after busulfan and then undergo large-scale apoptosis following cyclophosphamide. HFSC proliferation is activated through PI3K/Akt pathway, and depletion is driven by p53/p38-induced cell death. RNA-seq analysis shows that HFSCs experience mitotic catastrophe with G2/M checkpoint activation. Our findings indicate that priming mobilization causes stem cells to lose their resistance to DNA damage, resulting in permanent loss of regeneration after alkylating chemotherapy., Hair follicles (HFs) are sensitive to chemotherapy but recover from quiescent HF stem cells, although sometimes chemotherapy results in permanent loss. Here, Kim et al. establish a model of permanent chemotherapy-induced alopecia to uncover the underlying mechanisms depleting human HF stem cells.

In Wireless Sensor Networks (WSNs) for Internet of Things (IoT) environment, fault tolerance is a most fundamental issue due to strict energy constraint of sensor node. In this paper, a robust energy saving data dissemination protocol for IoT-WSNs is proposed. Minimized energy consumption and dissemination delay time based on signal strength play an important role in our scheme. The representative dissemination protocol SPIN (Sensor Protocols for Information via Negotiation) overcomes overlapped data problem of the classical Flooding scheme. However, SPIN never considers distance between nodes, thus the issue of dissemination energy consumption is becoming more important problem. In order to minimize the energy consumption, the shortest path between sensors should be considered to disseminate the data through the entire IoT-WSNs. SPMS (Shortest Path Mined SPIN) scheme creates routing tables using Bellman Ford method and forwards data through a multi-hop manner to optimize power consumption and delay time. Due to these properties, it is very hard to avoid heavy traffic when routing information is updated. Additionally, a node failure of SPMS would be caused by frequently using some sensors on the shortest path, thus network lifetime might be shortened quickly. In contrast, our scheme is resilient to these failures because it employs energy aware concept. The dissemination delay time of the proposed protocol without a routing table is similar to that of shortest path-based SPMS. In addition, our protocol does not require routing table, which needs a lot of control packets, thus it prevents excessive control message generation. Finally, the proposed scheme outperforms previous schemes in terms of data transmission success ratio, therefore our protocol could be appropriate for IoT-WSNs environment.

With the growing interest in big data technology, mobile IoT devices play an essential role in data collection. Generally, IoT sensor nodes are randomly distributed to areas where data cannot be easily collected. Subsequently, when data collection is impossible (i.e., sensing holes occurrence situation) due to improper placement of sensors or energy exhaustion of sensors, the sensors should be relocated. The cluster header in the sensing hole sends requests to neighboring cluster headers for the sensors to be relocated. However, it can be possible that sensors in the specific cluster zones near the sensing hole are continuously requested to move. With this knowledge, there can be a ping-pong problem, where the cluster headers in the neighboring sensing holes repeatedly request the movement of the sensors in the counterpart sensing hole. In this paper, we first proposed the near-uniform selection and movement scheme of the sensors to be relocated. By this scheme, the energy consumption of the sensors can be equalized, and the sensing capability can be extended. Thus the network lifetime can be extended. Next, the proposed relocation protocol resolves a ping-pong problem using queues with request scheduling. Another crucial contribution of this paper is that performance was analyzed using the fully-customed OMNeT++ simulator to reflect actual environmental conditions, not under over-simplified artificial network conditions. The proposed relocation protocol demonstrates a uniform and energy-efficient movement with ping-pong free capability.