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Droplet-based bioprinting enables the fabrication of cell–hydrogel–microfibre composite tissue precursors

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Bio-Design and Manufacturing 2022年第3期5卷 512-528页

作者： Marcin Kotlarz Ana M.Ferreira Piergiorgio Gentile Stephen j.Russell kenneth Dalgarno School of Engineering Newcastle UniversityNewcastle upon Tyne NE17RUUK School of Design University of LeedsLeeds LS29JTUK

Composites offer the option of coupling the individual benefits of their constituents to achieve unique material properties,which can be of extra value in many tissue engineering *** combining hydrogelswith fibre-based scaffolds can create tissue constructs with enhanced biological and structural ***,developing efficient and scalable approaches to manufacture such composites is ***,we use a droplet-based bioprinting system called reactive jet impingement(RejI)to integrate a cell-laden hydrogel with a microfibrous *** system uses microvalves connected to different bioink reservoirs and directed to continuously jet bioink droplets at one another in mid-air,where the droplets react and form a hydrogel that lands on a microfibrous ***–hydrogel–fibre composites are produced by embedding human dermal fibroblasts at two different concentrations(5×10^(6) and 30×10^(6) cells/mL)in a collagen–alginate–fibrin hydrogel matrix and bioprinted onto a fibre-based *** results show that both types of cell–hydrogel–microfibre composite maintain high cell viability and promote cell–cell and cell–biomaterial *** lower fibroblast density triggers cell proliferation,whereas the higher fibroblast density facilitates faster cellular organisation and infiltration into the ***,the fibrous component of the composite is characterised by high swelling properties and the quick release of calcium *** data indicate that the created composite constructs offer an efficient way to create highly functional tissue precursors for laminar tissue engineering,particularly for wound healing and skin tissue engineering applications.

关键词： Bioprinting Hydrogel–fibre composites High-cell-density hydrogels Composite manufacturing

Toward implantable devices for angle-sensitive,lens-less,multifluorescent,single-photon lifetime imaging in the brain using Fabry-Perot and absorptive color filters

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Light(Science & Applications) 2022年第2期11卷 197-211页

作者： Adriaan j.Taal Changhyuk Lee jaebin Choi Björn Hellenkamp kenneth L.Shepard Columbia University-Department of Electrical Engineering 500W.120th St.Mudd 1310New York 10027 NYUSA Korea Institute of Science and Technology-Brain Science Institute 5 Hwarang-ro 14-gilSeongbuk-guSeoul 02792Republic of Korea

Implantable image sensors have the potential to revolutionize *** to their small form factor requirements;however,conventional filters and optics cannot be *** limitations obstruct highresolution imaging of large neural *** advances in angle-sensitive image sensors and single-photon avalanche diodes have provided a path toward ultrathin lens-less fluorescence imaging,enabling plenoptic sensing by extending sensing capabilities to include photon arrival time and incident angle,thereby providing the opportunity for separability of fluorescence point sources within the context of light-field microscopy(LFM).However,the addition of spectral sensitivity to angle-sensitive LFM reduces imager resolution because each wavelength requires a separate pixel ***,we present a 1024-pixel,50μm thick implantable shank-based neural imager with color-filtergrating-based angle-sensitive *** angular-spectral sensitive front end combines a metal–insulator–metal(MIM)Fabry–Perot color filter and diffractive optics to produce the measurement of orthogonal light-field information from two distinct colors within a single *** result is the ability to add independent color sensing to LFM while doubling the effective pixel *** implantable imager combines angular-spectral and temporal information to demix and localize multispectral fluorescent *** this initial prototype,this is demonstrated with 45μm diameter fluorescently labeled beads in scattering *** lifetime imaging is exploited to further aid source separation,in addition to detecting pH through lifetime changes in fluorescent *** these initial fluorescent targets are considerably brighter than fluorescently labeled neurons,further improvements will allow the application of these techniques to in-vivo multifluorescent structural and functional neural imaging.

关键词： filters lifetime angle

Expanding beyond endoscopy: A review of non-invasive modalities in Barrett’s esophagus screening and surveillance

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World journal of Gastroenterology 2022年第32期28卷 4516-4526页

作者： Dariush Shahsavari Praneeth Kudaravalli john Erikson L Yap kenneth j Vega Division of Gastroenterology and Hepatology Augusta University-Medical College of GeorgiaAugustaGA 30912United States

Barrett’s esophagus(BE)is a condition that results from replacement of the damaged normal squamous esophageal mucosa to intestinal columnar mucosa and is the most significant predisposing factor for development of esophageal *** guidelines recommend endoscopic evaluation for screening and surveillance based on various risk factors which has limitations such as invasiveness,availability of a trained specialist,patient logistics and ***-nasal endoscopy is a less invasive modality but still has similar limitations such as limited availability of trained specialist and ***-endoscopic modalities,in comparison,require minimal intervention,can be done in an office visit and has the potential to be a more ideal choice for mass public screening and surveillance,particularly in patents at low risk for *** include newer generations of esophageal capsule endoscopy which provides direct visualization of BE,and tethered capsule endomicroscopy which can obtain high-resolution images of the *** cell collection devices coupled with biomarkers have been used for BE ***,in combination with TFF3,as well as EsophaCap and EsoCheck have shown promising results in various studies when used with various *** modalities including circulatory microRNAs and volatile organic compounds that have demonstrated favorable *** of these cell collection methods for BE surveillance is a potential area of future research.

关键词： Barrett’s esophagus Screening Surveillance Non-endoscopic Cytosponge Esophacap Esocheck

Stem cell therapy for the treatment of Leydig cell dysfunction in primary hypogonadism

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World journal of Stem Cells 2016年第10期8卷 306-315页

作者： Taylor C Peak Nora M Haney William Wang kenneth j DeLay Wayne j Hellstrom Department of Urology School of MedicineTulane University

The production of testosterone occurs within the Leydig cells of the testes. When production fails at this level from either congenital, acquired, or systemic disorders,the result is primary hypogonadism. While numerous testosterone formulations have been developed, none are yet fully capable of replicating the physiological patterns of testosterone secretion. Multiple stem cell therapies to restore androgenic function of the testes are under investigation. Leydig cells derived from bone marrow, adipose tissue, umbilical cord, and the testes have shown promise for future therapy for primary hypogonadism. In particular, the discovery and utilization of a group of progenitor stem cells within the testes, known as stem Leydig cells(SLCs), has led not only to a better understanding of testicular development, but of treatment as well. When combining this with an understanding of the mechanisms that lead to Leydig cell dysfunction, researchers and physicians will be able to develop stem cell therapies that target the specific step in the steroidogenic process that is deficient. The current preclinical studies highlight the complex nature of regenerating this steroidogenic process and the problems remain unresolved. In summary, there appears to be two current directions for stem cell therapy in male primary hypogonadism. The first method involves differentiating adult Leydig cells from stem cells of various origins from bone marrow, adipose, or embryonic sources. The second method involves isolating, identifying, and transplanting stem Leydig cells into testicular tissue. Theoretically, in-vivo re-activation of SLCs in men with primary hypogonadism due to age would be another alternative method to treat hypogonadism while eliminating the need for transplantation.

关键词： Stem cell therapy Leydig cells Primary hypogonadism Stem Leydig cells Testosterone Bone marrow-derived stem cells Adipose-derived mesenchymal stem cells

Engineered polymer nanoparticles incorporating L-amino acid groups as affinity reagents for fibrinogen

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journal of Pharmaceutical Analysis 2021年第5期11卷 596-602页

作者： Yongyan Zhu Ruixuan Liu Dengyu Wu Qianqian Yu kenneth j.Shea Quanhong Zhu School of Traditional Chinese Medicine Southern Medical UniversityGuangzhou510515China Guangdong Provincial Key Laboratory of Chinese Medicine Pharmaceutics Guangzhou510515China Guangdong Provincial Engineering Laboratory of Chinese Medicine Preparation Technology Guangzhou510515China Department of Chemistry University of CaliforniaIrvineCA92697USA

Synthetic polymer hydrogel nanoparticles(NPs)were developed to function as abiotic affinity reagents for *** NPs were made using both temperature-sensitive N-isopropyl acrylamide(NIPAm)and L-amino acid *** kinds of L-amino acids were acryloylated to obtain functional monomers:L-phenylalanine(Phe)and L-leucine(Leu)with hydrophobic side chains,L-glutamic acid(Glu)with negative charges,and L-lysine(Lys)and L-arginine(Arg)with positive *** incubating the NPs with fibrinogen,g-globulin,and human serum albumin(HSA)respectively,the NPs that incorporated Nacryloyl-Arg monomers(AArg@NPs)showed the strongest and most specific binding affinity to fibrinogen,when compared with g-globulin and ***,the fibrinogen-AArg binding model had the best docking scores,and this may be due to the interaction of positively charged AArg@NPs and the negatively charged fibrinogen D domain and the hydrophobic interaction between *** specific adsorption of AArg@NPs to fibrinogen was also confirmed by the immunoprecipitation assay,as the AArg@NPs selectively trapped the fibrinogen from a human plasma protein ***@NPs had a strong selectivity for,and specificity to,fibrinogen and may be developed as a potential human fibrinogen-specific affinity reagent.

关键词： Synthetic polymer nanoparticles Amino-acid monomers Arginine Fibrinogen Affinity reagent Protein interaction

Case study approach to modeling historical disinfection by-product exposure in Iowa drinking waters

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journal of Environmental Sciences 2017年第8期29卷 183-190页

作者： Stuart W.Krasner kenneth P.Cantor Peter j.Weyer Mariana Hildesheim Gary Amy Metropolitan Water District of Southern California Water Quality La Verne CA 91750 USA National Cancer Institute National Institutes of Health Bethesda MD 20892 USA Center for Health Effects of Environmental Contamination(CHEEC) University of Iowa Coralville IA 52242 USA Medical Research Solutions LLC Montgomery Village MD 20886 USA College of Engineering Computing and Applied SciencesClemson University Clemson SC 29631 USA

In the 1980 s, a case–control epidemiologic study was conducted in Iowa（USA） to analyze the association between exposure to disinfection by-products（DBPs） and bladder cancer risk. Trihalomethanes（THMs）, the most commonly measured and dominant class of DBPs in drinking water, served as a primary metric and surrogate for the full DBP *** THM exposure was calculated, based on rough estimates of past levels in Iowa. To reduce misclassification, a follow-up study was undertaken to improve estimates of past THM levels and to re-evaluate their association with cancer risk. In addition, the risk associated with haloacetic acids, another class of DBPs, was examined. In the original analysis, surface water treatment plants were assigned one of two possible THM levels depending on the point of chlorination. The re-assessment considered each utility treating surface or groundwater on a case-by-case basis. Multiple treatment/disinfection scenarios and water quality parameters were considered with actual DBP measurements to develop estimates of past levels. The highest annual average THM level in the re-analysis was156 μg/L compared to 74 μg/L for the original analysis. This allowed the analysis of subjects exposed at higher levels（〉 96 μg/L）. The re-analysis established a new approach, based on case studies and an understanding of the water quality and operational parameters that impact DBP formation, for determining historical exposure.

关键词： Disinfection by-products Trihalomethanes Haloacetic acids Exposure assessment Epidemiology Bladder cancer

Surface-bound myeloperoxidase is a ligand for recognition of late apoptotic neutrophils by human lung surfactant proteins A and D

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Protein & Cell 2010年第6期1卷 563-572页

作者： Anne jäkel Howard Clark kenneth B.M.Reid Robert B.Sim Department of Pharmacology University of OxfordMansfield RoadOxford OX13QTUK University of Southampton School of MedicineDivision of Infection Inflammation&ImmunitySouthampton General HospitalSouthampton SO166YDUK MRC Immunochemistry Unit Department of BiochemistryUniversity of OxfordSouth Parks RoadOxford OX13QUUK

Surfactant proteins A(SP-A)and D(SP-D),both members of the collectin family,play a well established role in apoptotic cell recognition and *** in vitro data show that SP-A and SP-D interact with apoptotic neutrophils in a distinct ***-A and SP-D bind in a Ca^(2+)-dependent manner to viable and early apoptotic neutrophils whereas the much greater interaction with late apoptotic neutrophils is Ca^(2+)-*** surface molecules on the apoptotic target cells responsible for these interactions had not been identified and this study was done to find candidate target ***(MPO),a specific intracellular defense molecule of neutrophils that becomes exposed on the outside of the cell upon apoptosis,was identified by affinity purification,mass-spectrometry and western blotting as a novel binding molecule for SP-A and *** confirm its role in recognition,it was shown that purified immobilised MPO binds SP-A and SP-D,and that MPO is surface-exposed on late apoptotic ***-A and SP-D inhibit binding of an anti-MPO monoclonal Ab to late apoptotic *** microscopy confirmed that anti-MPO mAb and SP-A/SP-D colocalise on late apoptotic *** was identified as a further potential ligand for SP-A,and neutrophil defensin as a target for both proteins.

关键词： SP-A SP-D myeloperoxidase neutrophils flow cytometry mass spectrometry

Elevated temperature intensity,timing,and duration of exposure affect soybean internode elongation,mainstem node number,and pod number per plant

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The Crop journal 2018年第2期6卷 148-161页

作者： Leon Hartwell Allen jr. Lingxiao Zhang kenneth j.Boote Bernard A.Hauser U.S.Department of Agriculture-Agricultural Research Service GainesvilleFL 32608USA Department of Agronomy University of FloridaGainesvilleFL 32611USA Department of Biology University of FloridaGainesvilleFL 32611USA

A study was conducted in four compartments of a polycarbonate greenhouse at Gainesville,FL, USA to investigate how a soybean(Glycine max L. Merr.) cultivar, Maverick(maturity group III, indeterminate), responded to three elevated temperatures, ELT,(day/night of 34/26 °C, 38/30 °C, and 42/34 °C) in comparison to a control growth temperature(30/22 °C).Carbon dioxide(CO_2) concentration was maintained at 700 μmol mol^(-1) in each compartment by a processor controlled air-sampling and CO_2-injection system. Three sequential experiments were conducted at different times of year(summer, autumn, and early spring)to investigate the effect of intensity, timing, and duration of ELT on soybean node number,internode elongation, mainstem length, and number of pods set per plant. At the control temperature, the soybean plants grown in the polycarbonate greenhouse were taller than field-grown plants. When plants were grown under continuous ELT applied soon after sowing or at initial flowering, the number of nodes increased with increasing ELT intensity,whereas the length of individual internodes decreased. When ELT treatment was applied during the beginning of flowering stage(R1–R2) or earlier, more nodes were produced and the length of affected internodes was decreased. When the ELT was imposed later at reproductive stage R5+ just before the beginning of seed filling, effects on node numbers and internode lengths were negligible. Short-term(10-day) duration of ELT applied at four stages from V3 to R5+ did not significantly affect final mean numbers of nodes or mean mainstem lengths. Possible mechanisms of elevated temperature effects on soybean internode elongation and node number(internode number) are discussed. Total pod numbers per plant increased linearly with mainstem node numbers and mainstem ***, total pod numbers per plant were greatest at 34/26 °C rather than at the control temperature of 30/22 °C(and remained high at 38/30 °C). Mild increases in temperatu

关键词： Elevated temperature Internode elongation Node number Pod yield Soybean phenology

Kinematics, dynamics, and design of machinery / 2nd ed.

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