Engineering vascularized organotypic tissues via module assembly

Adequate vascularization is a critical determinant for the successful construction and clinical implementation of complex organotypic tissue models. Currently, low cell and vessel density and insufficient vascular maturation make vascularized organotypic tissue construction difficult,greatly limiting its use in tissue engineering and regenerative medicine. To address these limitations, recent studies have adopted pre-vascularized microtissue assembly for the rapid generation of functional tissue analogs with dense vascular networks and high cell density. In this article, we summarize the development of module assembly-based vascularized organotypic tissue construction and its application in tissue repair and regeneration, organ-scale tissue biomanufacturing, as well as advanced tissue modeling.

Trends in Extra-Ovarian Cancer Tissues and Organs Resection in Patients with Ovarian Cancer

Ovarian cancer mostly presents with extensive peritoneal cavity and extraperitoneal dissemination. Satisfactory and complete resection of the lesions is one of the key factors to improve the prognosis. The trend of surgical resection of extra-ovarian tissues and organs invaded by the tumor has become obvious in order to remove all primary loci and all metastases as much as possible to minimize residual tumor lesions. This article provides a literature review on organ resection in ovarian cancer cytoreduction, summarizing the perioperative complications and survival outcomes at the time of different organ surgery, with the aim of providing guidance for clinical work.

Role of nanotopography in the development of tissue engineered 3D organs and tissues using mesenchymal stem cells

Recent regenerative medicine and tissue engineering strategies(using cells, scaffolds, medical devices and gene therapy) have led to fascinating progress of translation of basic research towards clinical applications. In the past decade, great deal of research has focused on developing various three dimensional(3D) organs, such as bone, skin, liver, kidney and ear,using such strategies in order to replace or regenerate damaged organs for the purpose of maintaining or restoring organs' functions that may have been lost due to aging, accident or disease. The surface properties of a material or a device are key aspects in determining the success of the implant in biomedicine, as the majority of biological reactions in human body occur on surfaces or interfaces. Furthermore, it has been established in the literature that cell adhesion and proliferation are, to a great extent, influenced by the micro- and nanosurface characteristics of biomaterials and devices. In addition, it has been shown that the functions of stem cells, mesenchymal stem cells in particular, could be regulated through physical interaction with specific nanotopographical cues. Therefore, guided stem cell proliferation, differentiation and function are of great importance in the regeneration of 3D tissues and organs using tissue engineering strategies. This review will provide an update on the impact of nanotopography on mesenchymal stem cells for the purpose of developing laboratory-based 3D organs and tissues, as well as the most recent research and case studies on this topic.

The future of artificial hibernation medicine:protection of nerves and organs after spinal cord injury

Spinal cord injury is a serious disease of the central nervous system involving irreversible nerve injury and various organ system injuries.At present,no effective clinical treatment exists.As one of the artificial hibernation techniques,mild hypothermia has preliminarily confirmed its clinical effect on spinal cord injury.However,its technical defects and barriers,along with serious clinical side effects,restrict its clinical application for spinal cord injury.Artificial hibernation is a futureoriented disruptive technology for human life support.It involves endogenous hibernation inducers and hibernation-related central neuromodulation that activate particular neurons,reduce the central constant temperature setting point,disrupt the normal constant body temperature,make the body adapt"to the external cold environment,and reduce the physiological resistance to cold stimulation.Thus,studying the artificial hibernation mechanism may help develop new treatment strategies more suitable for clinical use than the cooling method of mild hypothermia technology.This review introduces artificial hibernation technologies,including mild hypothermia technology,hibernation inducers,and hibernation-related central neuromodulation technology.It summarizes the relevant research on hypothermia and hibernation for organ and nerve protection.These studies show that artificial hibernation technologies have therapeutic significance on nerve injury after spinal co rd injury through inflammatory inhibition,immunosuppression,oxidative defense,and possible central protection.It also promotes the repair and protection of res pirato ry and digestive,cardiovascular,locomoto r,urinary,and endocrine systems.This review provides new insights for the clinical treatment of nerve and multiple organ protection after spinal cord injury thanks to artificial hibernation.At present,artificial hibernation technology is not mature,and research fa ces various challenges.Neve rtheless,the effort is wo rthwhile for the future development of medicine.

A novel semi-dominant allele of the transmembrane NAC transcription factor ZmNTL2 reduces the size of multiple maize organs

Maize plant architecture influences planting density and,in turn,grain yield.Most of the plant architecture-related traits can be described as organ size.We describe a miniature maize mutant,Tiny plant 4(Tip4),which exhibits reduced size of multiple organs and exhibits a semi-dominant monofactorial inheritance characteristic.Positional cloning confirmed that a 4-bp deletion in the NAC TF with transmembrane motif 1-Like(NTL)gene ZmNTL2,denoted as ZmNTL2^(Δ),confers the Tip4 mutation.qRT-PCR showed that ZmNTL2 was expressed in all tested tissues.ZmNTL2 functions as a transcriptional activator and is located in both the nucleus and biomembranes.The mutation does not affect the mRNA abundance of ZmNTL2 locus,but it does result in the loss of transmembrane domain and confines the ZmNTL2^(Δ)protein to the nucleus.Knocking out ZmNTL2 has no effect on maize organ size development,indicating that the 4-bp deletion might be a gain-of-function mutation in organ size regulation.Combining transcriptome sequencing with cytokinin and auxin content determination suggests that the decreased organ size may be possibly mediated by changes in hormone homeostasis.

The storage and utilization of carbohydrates in response to elevation mediated by tree organs in subtropical evergreen broad-leaved forests

Global climate change can affect tree growth and carbon sink function by influencing plant carbohydrate synthesis and utilization,while elevation can be used as an ideal setting under natural conditions to simulate climate change effects.The effect of elevation on tree growth may depend on organ type.However,the allocation patterns of nonstructural and structural carbohydrates(NSCs and SCs,respectively)in different tree organs and their response to elevation remain unclear.We selected four dominant tree species,Schima superba,Castanopsis eyrei,Castanopsis fargesii and Michelia maudiae,along an elevation gradient from 609 to 1,207 m in subtropical evergreen broad-leaved forests and analyzed leaf,trunk,and fine root NSCs,carbon(C),nitrogen(N)and phosphorus(P)concentrations and the relative abundance of SCs.Leaf NSCs increased initially and then decreased,and trunk NSCs increased with increasing elevation.However,root NSCs decreased with increasing elevation.The relative abundance of SCs in leaves and trunks decreased,while the relative abundance of root SCs increased with increasing elevation.No significant correlations between SCs and NSCs in leaves were detected,while there were negative correlations between SCs and NSCs in trunks,roots,and all organs.Hierarchical partitioning analysis indicated that plant C/N and C/P were the main predictors of changes in SCs and NSCs.Our results suggest that tree organs have divergent responses to elevation and that increasing elevation will inhibit the aboveground part growth and enhance the root growth of trees.A tradeoff between the C distribution used for growth and storage was confirmed along the elevation gradient,which is mainly manifested in the"sink"organs of NSCs.Our results provide insight into tree growth in the context of global climate change scenarios in subtropical forest ecosystems.

3D Bioprinting:A Novel Avenue for Manufacturing Tissues and Organs

Three-dimensional(3D)bioprinting is a rapidly growing technology that has been widely used in tissue engineering,disease studies,and drug screening.It provides the unprecedented capacity of depositing various types of biomaterials,cells,and biomolecules in a layer-by-layer fashion,with precisely controlled spatial distribution.This technology is expected to address the organ-shortage issue in the future.In this review,we first introduce three categories of 3D bioprinting strategies:inkjet-based printing(IBP),extrusion-based printing(EBP),and light-based printing(LBP).Biomaterials and cells,which are normally referred to as“bioinks,”are then discussed.We also systematically describe the recent advancements of 3D bioprinting in fabricating cell-laden artificial tissues and organs with solid or hollow structures,including cartilage,bone,skin,muscle,vascular network,and so on.The development of organs-onchips utilizing 3D bioprinting technology for drug discovery and toxicity testing is reviewed as well.Finally,the main challenges in current studies and an outlook of the future research of 3D bioprinting are discussed.

Repair cell first,then regenerate the tissues and organs

Wound healing,tissue repair and regenerative medicine are in great demand,and great achievements in these fields have been made.The traditional strategy of tissue repair and regeneration has focused on the level of tissues and organs directly;however,the basic process of repair at the cell level is often neglected.Because the cell is the basic unit of organism structure and function;cell damage is caused first by ischemia or ischemia-reperfusion after severe trauma and injury.Then,damage to tissues and organs occurs with massive cell damage,apoptosis and even cell death.Thus,how to achieve the aim of perfect repair and regeneration?The basic process of tissue or organ repair and regeneration should involve repair of cells first,then tissues and organs.In this manuscript,it is my consideration about how to repair the cell first,then regenerate the tissues and organs.

ELEMENTAL CONTENTS IN ORGANS AND TISSUES OF CHINESE ADULT MEN

Objective To provide basis of reference values for relevant parameters of Chinese Reference Man. Methods Eighteen kinds of major organ or tissue samples, including muscle, rib, liver, and so on, were obtained from 4 areas (Hebei, Shanxi, Jiangsu, and Sichuan provinces) with different dietary patterns in China in autopsy of 16 healthy adult men, who had just encountered sudden deaths. At the same time, whole blood samples were collected from 10 volunteers living in each of these areas. The concentrations of 56 elements in these samples were detected by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), and Graphite Furnace Atomic Absorption Spectrometry (GF-AAS) techniques. Based on obtained concentrations and reference values of these organ or tissue weights for Chinese Reference Man, the relative elemental burdens in these organs or tissues as well whole body were also estimated. Results The concentrations of 56 elements in 18 main organs or tissues were determined all together and their elemental organ or tissue and whole body burdens were estimated. Furthermore, the distributions of important elements for radiation protection in these organs or tissues were emphatically discussed. Conclusion By summing with past related results, the total results obtained from the series of research may provide more reliable and better representative basis of these reference values for Chinese Reference Man than before.

New native tissue repair for pelvic organ prolapse:Medium-term outcomes of laparoscopic vaginal stump-round ligament fixation

BACKGROUND Laparoscopic sacrocolpopexy for pelvic organ prolapse(POP)is a new and widely used approach;however,ever since the United States Food and Drug Administration warned against the use of surgical mesh,repairs performed using patients’tissues[i.e.native tissue repair(NTR)]instead of mesh have attracted much attention.At our hospital,laparoscopic sacrocolpopexy(the Shull method)was introduced in 2017.However,patients with more severe POP who have a long vaginal canal and overextended uterosacral ligaments may not be candidates for this procedure.AIM To validate a new NTR treatment for POP,we examined patients undergoing laparoscopic vaginal stump–round ligament fixation(the Kakinuma method).METHODS The study patients were 30 individuals with POP who underwent surgery using the Kakinuma method between January 2020 and December 2021 and who were followed up for>12 mo after surgery.We retrospectively examined surgical outcomes for surgery duration,blood loss,intraoperative complications,and incidence of recurrence.The Kakinuma method involves round ligament suturing and fixation on both sides,effectively lifting the vaginal stump after laparoscopic hysterectomy.RESULTS The patients’mean age was 66.5±9.1(45-82)years,gravidity was 3.1±1.4(2-7),parity was 2.5±0.6(2-4)times,and body mass index was 24.5±3.3(20.9-32.8)kg/m2.According to the POP quantification stage classification,there were 8 patients with stage Ⅱ,11 with stage Ⅲ,and 11 with stage Ⅳ.The mean surgery duration was 113.4±22.6(88-148)min,and the mean blood loss was 26.5±39.7(10-150)mL.There were no perioperative complications.None of the patients exhibited reduced activities of daily living or cognitive impairment after hospital discharge.No cases of POP recurrence were observed 12 mo after the operation.CONCLUSION The Kakinuma method,similar to conventional NTR,may be an effective treatment for POP.

Depolarizing metrics in the biomedical field:Vision enhancement and classification of biological tissues

Polarimetry encompasses a collection of optical techniques broadly used in a variety of fields.Nowadays,such techniques have provided their suitability in the biomedical field through the study of the polarimetric response of biological samples(retardance,dichroism and depolarization)by measuring certain polarimetric observables.One of these features,depolarization,is mainly produced by scattering on samples,which is a predominant efiect in turbid media as biological tissues.In turn,retardance and dichroic efiects are produced by tissue anisotropies and can lead to depolarization too.Since depolarization is a predominant efiect in tissue samples,we focus on studying difierent depolarization metrics for biomedical applications.We report the suitability of a set of depolarizing observables,the indices of polarimetric purity(IPPs),for biological tissue inspection.We review some results where we demonstrate that IPPs lead to better performance than the depolarization index,which is a well-established and commonly used depolarization observable in the literature.We also provide how IPPs are able to significantly enhance contrast between difierent tissue structures and even to reveal structures hidden by using standard intensity images.Finally,we also explore the classificatory potential of IPPs and other depolarizing observables for the discrimination of difierent tissues obtained from ex vivo chicken samples(muscle,tendon,myotendinous junction and bone),reaching accurate models for tissue classification.

Bio-effects of 5th generation electromagnetic waves on organs of human beings

Objectives:The uses of devices of electromagnetic waves(EMWs)are increasing day by day.Similarly,the generation of the waves is increasing.The frequency spectrum of the generation of waves is also increased.In this manuscript,an analysis of the high frequency EMWs has been made by the electric fields generated due to the exposure of 5th generation(5 G)of mobile phones.Methods:Due to the emission of waves from the towers,the electric field is generated around the transmission tower of mobile phones.The electric fields are computed by the power of the transmission tower.The electric fields across the biological tissues/cells are also computed when the EMWs penetrate inside the body.The electric fields are made across the organs of different depths inside the body.Results:The induced electric fields inside the organs of the human beings are responsible for the absorption of energy from high frequency EMWs.The absorbed amount of energy from high frequency waves may become the cause of harmful effects on the life of organs of human beings.Conclusion:In this manuscript,after analysis of the computed electric fields inside the organs of human beings,it is concluded that the EMWs of 5 G spectrum of mobile phone towers may more harmful for the life of organs as 4th generation(4 G)spectrum of mobile phone waves.The energy absorption by the 4 G spectrum is lower than 5 G spectrum due to the range of frequency of waves.The effects on the pancreas,retina,skin,intestine,spleen,stomach and uterus are more than low water content organs like nails,bone,teeth etc.

Reorganization of 3D genome architecture across wild boar and Bama pig adipose tissues

Background:A growing body of evidence has revealed that the mammalian genome is organized into hierarchical layers that are closely correlated with and may even be causally linked with variations in gene expression.Recent studies have characterized chromatin organization in various porcine tissues and cell types and compared them among species and during the early development of pigs.However,how chromatin organization differs among pig breeds is poorly understood.Results:In this study,we investigated the 3D genome organization and performed transcriptome characterization of two adipose depots(upper layer of backfat[ULB]and greater omentum[GOM])in wild boars and Bama pigs;the latter is a typical indigenous pig in China.We found that over 95%of the A/B compartments and topologically associating domains(TADs)are stable between wild boars and Bama pigs.In contrast,more than 70%of promoterenhancer interactions(PEIs)are dynamic and widespread,involving over a thousand genes.Alterations in chromatin structure are associated with changes in the expression of genes that are involved in widespread biological functions such as basic cellular functions,endocrine function,energy metabolism and the immune response.Approximately 95%and 97%of the genes associated with reorganized A/B compartments and PEIs in the two pig breeds differed between GOM and ULB,respectively.Conclusions:We reported 3D genome organization in adipose depots from different pig breeds.In a comparison of Bama pigs and wild boar,large-scale compartments and TADs were mostly conserved,while fine-scale PEIs were extensively reorganized.The chromatin architecture in these two pig breeds was reorganized in an adipose depotspecific manner.These results contribute to determining the regulatory mechanism of phenotypic differences between Bama pigs and wild boar.

Biomimetic natural biomaterials for tissue engineering and regenerative medicine:new biosynthesis methods,recent advances,and emerging applications

Biomimetic materials have emerged as attractive and competitive alternatives for tissue engineering(TE)and regenerative medicine.In contrast to conventional biomaterials or synthetic materials,biomimetic scaffolds based on natural biomaterial can offer cells a broad spectrum of biochemical and biophysical cues that mimic the in vivo extracellular matrix(ECM).Additionally,such materials have mechanical adaptability,micro-structure interconnectivity,and inherent bioactivity,making them ideal for the design of living implants for specific applications in TE and regenerative medicine.This paper provides an overview for recent progress of biomimetic natural biomaterials(BNBMs),including advances in their preparation,functionality,potential applications and future challenges.We highlight recent advances in the fabrication of BNBMs and outline general strategies for functionalizing and tailoring the BNBMs with various biological and physicochemical characteristics of native ECM.Moreover,we offer an overview of recent key advances in the functionalization and applications of versatile BNBMs for TE applications.Finally,we conclude by offering our perspective on open challenges and future developments in this rapidly-evolving field.

Selection and Validation of Reference Genes for Normalization of RT-qPCR Analysis in Developing or Abiotic-Stressed Tissues of Loquat (Eriobotrya japonica)

Loquat(Eriobotrya japonica Lindl.)is a subtropical evergreen fruit tree that produces fruits with abundant nutrients and medicinal components.Confirming suitable reference genes for a set of loquat samples before qRT-PCR experiments is essential for the accurate quantification of gene expression.In this study,eight candidate reference genes were selected from our previously published RNA-seq data,and primers for each candidate reference gene were designed and evaluated.The Cq values of the candidate reference genes were calculated by RT-qPCR in 31 different loquat samples,including 12 subgroups of developing or abiotic-stressed tissues.Different combinations of stable reference genes were screened according to a comprehensive rank,which was synthesized from the results of four algorithms,including the geNorm,NormFinder,BestKeeper andΔCt methods.The screened reference genes were verified by normalizing EjLGA1 in each subgroup.The obtained suitable combinations of reference genes for accurate normalization were GAPDH,EF1αand ACT for floral development;GAPDH,UBCE and ACT for fruit setting;EF1α,GAPDH and eIF2B for fruit ripening;ACT,EF1αand UBCE for leaves under heat stress;eIF2B,UBCE and EF1αfor leaves under freezing stress;EF1α,TUA and UBCE for leaves under salt stress;ACT,EF1αand eIF2B for immature pulp under freezing stress;ACT,UBCE and eIF2B for immature seeds under freezing stress;EF1α,eIF2B and UBCE for both immature pulp and seeds under freezing stress;UBCE,TUB and TUA for red-fleshed fruits under cold-storage stress;eIF2B,RPS3 and TUB for white-fleshed fruits under coldstorage stress;and eIF2B,UBCE and RPS3 for both red-and white-fleshed fruits under cold-storage stress.This study obtained different combinations of stable reference genes for accurate normalization in twelve subgroups of developing or abiotic-stressed tissues in loquat.To our knowledge,this is the first report to obtain stable reference genes for normalizing gene expression of abiotic-stressed tissues in E.japonica.The use of the three most stable reference genes could increase the reliability of future quantification experiments.

Detection of Low-Risk and High-Risk Oncogenic Human Papillomavirus in Archived Tissues from ENT Tumors in Burkina Faso

Human papillomavirus (HPV) is classified into high-risk HPV (HR-HPV) and HPV (LR-HPV) according to their oncogenic potential. These viruses can be found in the cervix, vagina, vulva, anus and in the ENT sphere. HPV ENT infections can lead to benign or malignant tumors in which we could find both LR-HPV and HR-HPV genotypes. The objective of this study was to investigate the genotypes of HR-HPV and LR-HPV in archived tissue samples derived from both benign and malignant tumors of the ear, nose, and throat (ENT) in Ouagadougou, Burkina Faso. One hundred and twenty formalin-fixed, paraffin-embedded archived tissues of the ENT sphere from 26 benign tumors and 94 malignant tumors were included. The tissues were first deparaffinized with xylem. The extracted DNA was used to test for high-risk and low-risk HPV by Real-Time Multiplex PCR. HPV DNA was found in 57.7% (15/26) of benign tumors and 43.61% (41/94) of malignant tumors. The prevalence of HPV infection was 46.67% (56/120) in all tumors combined. The most common HPV genotypes found were HPV 11 (34.28%), HPV 6 (30%), HPV56 (14.28%) and HPV 33 (8.57%). There were 21.43% (12/56) cases of genotypes co-infections with 10 cases of double infection and 2 cases of triple infection. Both low-risk and high-risk HPV are found in ENT tumors with relatively high HPV prevalence.

Coupling of reduced inorganic fertilizer with plant-based organic fertilizer as a promising fertilizer management strategy for colored rice in tropical regions

Colored rice is a type of high-quality,high-added-value rice that has attracted increasing attention in recent years.The use of large amounts of inorganic nitrogen fertilizer in rice fields results in low fertilizer use efficiency and high environmental pollution.Organic fertilizer is a promising way to improve soil quality and sustain high yields.However,most studies focus on the effect of animal-based organic fertilizers.The effects of different ratios of plantbased organic fertilizer and inorganic fertilizer on the grain yield and quality of colored rice have rarely been reported.Therefore,a two-year field experiment was conducted in 2020 and 2021 to study the effects of replacing inorganic N fertilizers with plant-based organic fertilizers on the yield,nitrogen use efficiency(NUE),and anthocyanin content of two colored rice varieties in a tropical region in China.The experimental treatments included no nitrogen fertilization(T1),100% inorganic nitrogen fertilizer(T2),30%inorganic nitrogen fertilizer substitution with plant-based organic fertilizer(T3),60%inorganic nitrogen fertilizer substitution with plant-based organic fertilizer(T4),and 100% plantbased organic fertilizer(T5).The total nitrogen provided to all the treatments except T1 was the same at 120 kg ha-1.Our results showed that the T3 treatment enhanced the grain yield and anthocyanin content of colored rice by increasing nitrogen use efficiency compared with T2.On average,grain yields were increased by 9 and 8%,while the anthocyanin content increased by 16 and 10% in the two colored rice varieties under T3 across the two years,respectively,as compared with T2.Further study of the residual effect of partial substitution of inorganic fertilizers showed that the substitution of inorganic fertilizer with plant-based organic fertilizer improved the soil physiochemical properties,and thus increased the rice grain yield,in the subsequent seasons.The highest grain yield of the subsequent rice crop was observed under the T5 treatment.Our results suggested that the application of plantbased organic fertilizers can sustain the production of colored rice with high anthocyanin content in tropical regions,which is beneficial in reconciling the relationship between rice production and environmental protection.

Mercury accumulation,distribution,and isotopic composition in tissues of the Collared Scops Owl(Otus lettia)

Mercury is a ubiquitous contaminant known to accumulate in wildlife,particularly bird species at higher trophic levels.Knowledge of tissue-specific Hg distributions aids our understanding of Hg bioaccumulation in organisms.In this study,one adult and three juvenile Collared Scops Owls(Otus lettia)were studied to elucidate the bioaccumulation of Hg in body tissues.Six tissues and organs(feathers,nails,heart,liver,gizzard,and muscle),as well as gastric contents,were examined for total Hg(THg)and methylmercury(MeHg)contents,Hg isotopic compositions including mass-dependent fractionation(MDF;δ202Hg)and mass-independent fractionation(MIF;Δ199Hg andΔ201Hg),and C(δ13C)and N(δ15N)isotopic compositions.Tissue-specific THg and MeHg concentrations in the adult were in the ranges of 150–1360 ng/g and17–1060 ng/g,and lower in the juveniles at 91–419 ng/g and 67–350 ng/g,respectively.Theδ^(202)Hg values in the adult were strongly negative at-1.75‰±0.17‰compared with the juveniles at-0.99‰±0.25‰.The adult exhibited lower MIF values than the juveniles,at0.23‰±0.07‰forΔ^(199)Hg and 0.2‰±0.11‰forΔ^(201)Hg,comparedwith0.81‰±0.09‰and0.66‰±0.07‰,respectively.The lower adult MDF and MIF values suggest that the adult tended to accumulate negative Hg isotopes but the juvenile's positive Hg isotopes.Differences between adult and juvenile tissue Hg concentrations indicate that metabolic processes play an important role in Hg accumulation.

Wideband frequency-dependent dielectric properties of rat tissues exposed to low-intensity focused ultrasound in the microwave frequency range

Tissue dielectric properties can vary upon the incident of an acoustic wave.The goal of this study is to quantify this change due to the acoustoelectric effect(AE),and to obtain the frequency-dependent dielectric properties of tissues exposed to low-intensity focused ultrasound(LIFU).The dielectric properties of the blood,brain,chest muscle,heart,kidney,leg muscle,liver,lung,pancreas,and spleen of rats were measured by an open-ended coaxial probe method.The acoustic intensity of LIFU focus was 2.97 MPa(67.6 W/cm^(2)),3.95 MPa(120 W/cm^(2)),and 5.17 MPa(204 W/cm^(2)),respectively,and the measurement frequency band was 0.1–7.08 GHz.The measurement results show that with the LIFU modulation,the conductivity and dielectric constant decreased in the high-frequency band,and on the contrary,they increased in the lowfrequency band,and the larger the acoustic intensity was,the more obvious the phenomenon was.This work contributes to a better understanding of the mechanisms by which ultrasound acts on the dielectric properties of biological tissues.It is expected that the findings from this study will provide a basis that the response of tissue to LIFU modulation can be monitored by noninvasive techniques such as microwave-induced thermoacoustic imaging(MTI)and microwave imaging,present a new idea for improving the endogenous contrast between different biological tissues in MTI and acoustoelectric imaging,and possibly lead to the development of a new imaging method based on the relaxation time of tissue after LIFU modulation.

Heat transport properties within living biological tissues with temperature-dependent thermal properties

Understanding of the heat transport within living biological tissues is crucial to effective heat treatments. The heat transport properties of living biological tissues with temperature-dependent properties are explored in this paper. Taking into account of variable physical properties, the governing equation of temperature is first derived in the context of the dualphase-lags model(DPL). An effective method, according to the Laplace transform and a linearization technique, is then employed to solve this nonlinear governing equation. The temperature distribution of a biological tissue exposed to a pulsed heat flux on its exterior boundary, which frequently happens in various heat treatments, is predicted and analyzed. The results state that a lower temperature can be predicted when temperature dependence is considered in the heating process.The contributions of key thermal parameters are different and dependent on the ratio of phase lag and the amplitude of the exterior pulsed heat flux.