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1.
Acc Chem Res ; 2024 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-39373712

RESUMO

ConspectusNickel pincer systems have recently attracted much attention for applications in various organometallic reactions and catalysis involving small molecule activation. Their exploration is in part motivated by the presence of nickel in natural systems for efficient catalysis. Among such systems, the nickel-containing metalloenzyme carbon monoxide dehydrogenase (CODH) efficiently and reversibly converts CO2 to CO at its active site. The generated CO moves through a channel from the CODH active site and is transported to a dinuclear nickel site of acetyl-coenzyme A synthase (ACS), which catalyzes organometallic C-S and C-C bond forming reactions. An analogous C-S bond activation process is also mediated by the nickel containing enzyme methyl-coenzyme M reductase (MCR). The nickel centers in these systems feature sulfur- and nitrogen-rich environments, and in the particular case of lactate racemase, an organometallic nickel pincer motif revealing a Ni-C bond is observed. These bioinorganic systems inspired the development of several nickel pincer scaffolds not only to mimic enzyme active sites and their reactivity but also to further extend low-valent organonickel chemistry. In this Account, we detail our continuing efforts in the chemistry of nickel complexes supported by acridane-based PNP pincer ligands focusing on our long-standing interest in biomimetic small molecule activation. We have employed a series of diphosphinoamide pincer ligands to prepare various nickel(II/I/0) complexes and to study the conversion of C1 chemicals such as CO and CO2 to value-added products. In the transformation of C1 chemicals, the key C-O bond cleavage and C-E bond (E = C, N, O, or S, etc.) formation steps typically require overcoming high activation barriers. Interestingly, enzymatic systems overcome such difficulties for C1 conversion and operate efficiently under ambient conditions with the use of nickel organometallic chemistry. Furthermore, we have extended our efforts to the conversion of NOx anions to NO via the sequential deoxygenation by nickel mediated carbonylation, which was applied to catalytic C-N coupling to produce industrially important organonitrogen compound oximes as a strategy for NOx conversion and utilization (NCU). Notably, the rigidified acriPNP pincer backbone that enforces a planar geometry at nickel was found to be an important factor for diversifying organometallic transformations including (a) homolysis of various σ-bonds mediated by T-shaped nickel(I) metalloradical species, (b) C-H bond activation mediated by a nickel(0) dinitrogen species, (c) selective CO2 reactivity of nickel(0)-CO species, (d) C-C bond formation at low-valent nickel(I or 0)-CO sites with iodoalkanes, and (e) catalytic deoxygenation of NOx anions and subsequent C-N coupling of a nickel-NO species with alkyl halides for oxime production. Broadly, our results highlight the importance of molecular design and the rich chemistry of organonickel species for diverse small molecule transformations.

2.
J Am Chem Soc ; 2024 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-39465544

RESUMO

Lipopeptides are an important family of natural products, some of which are clinically used as antibiotics to treat multidrug-resistant pathogens. Although the lipid moieties play a crucial role in balancing antibacterial activity and hemolytic toxicity, modifying the lipid moieties has been challenging due to the complexity of the lipidation process in lipopeptide biosynthesis. Here, we show that the lipid profile can be altered by engineering both secondary and primary metabolisms, using daptomycin as an example. First, swapping the fatty acyl AMP ligase (FAAL) gene dptF with foreign FAAL homologs improved the fatty acyl specificity of the lipidation process for decanoic acid. Then, the introduction of Mycobacterium type I fatty acid synthase operon (MvFAS-Ib/MvAcpS) and Cryptosporidium thioesterase (CpTEII) enriched the fatty acid pool with decanoic acid in Streptomyces roseosporus. The engineered fatty acid metabolism eliminates the need for external decanoic acid supplementation by enabling S. roseosporus to biosynthesize decanoic acid. By complete engineering of the lipidation process, we achieved, for the first time, high-purity, natural production of daptomycin. The lipidation engineering approach we demonstrate here lays the foundation for the lipidation control in lipopeptide biosynthesis.

3.
Inorg Chem ; 62(7): 3007-3017, 2023 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-36753609

RESUMO

A phosphide nickel(II) phenoxide pincer complex (2) reacts with CO(g) to give a pseudo-tetrahedral nickel(0) monocarbonyl complex (3) possessing a phosphinite moiety. This metal-ligand cooperative (MLC) transformation occurs with a (PPP)Ni scaffold (PPP- = P[2-PiPr2-C6H4]2-), which can accommodate both square planar and tetrahedral geometries. The 2-electron reduction of a nickel(II) species induced by CO coordination involves group transfer to generate a P-O bond. For better mechanistic understanding, a series of nickel(II) phenolate complexes (2a-2e, XC6H4O- (X = OMe, Me, H, and CF3) and pentafluorophenolate) were prepared. Kinetic experimental data reveal that a phenolate species with an electron-withdrawing group reacts faster than those with electron-donating groups. The reaction kinetic experiments were conducted in pseudo-first order conditions at room temperature monitored by UV-vis spectroscopy. A pentafluorophenolate nickel(II) complex (2e) reveals instantaneous reactions even at -40 °C to give a nickel(0) monocarbonyl species (3e) and the reverse reaction is also possible. According to kinetic experiments, the rate determining step (RDS) would be the formation of a 5-coordinate intermediate 4 with a negative entropy value (ΔS‡ < 0), and a positive ρ value based on the Hammett plot indicates that the electron-deficient phenolate leads to a faster CO association. Furthermore, scramble experiments suggest that phenolate de-coordinates from the intermediate 4, which gives a (PPP)Ni-CO species 6. The cationic nickel monocarbonyl intermediate can possess a P--Ni(II), P•-Ni(I), or even a P+-Ni(0) character. Such an inner-sphere electron transfer is suggested when a π-acidic ligand such as CO coordinates to a metal ion. Another possible reaction is homolysis of a Ni-O bond to give P--Ni(I) or P•-Ni(0), when a phenoxyl radical is liberated. Considering the P-O bond formation, closed-shell nucleophilic and open-shell radical pathways are suggested. A phenolate pathway reveals a lower energy state for 2e relative to other complexes (2c and 2d), while its radical pathway undergoes via a higher energy state. Therefore, the formation of a P-O bond may occur with the binding of a closed-shell phenolate to the electron-deficient P center.

4.
Appl Opt ; 58(14): 3676-3684, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-31158178

RESUMO

A temporal phase unwrapping method is proposed to generate an unwrapped phase map for a robust three-dimensional (3D) scan. The proposed algorithm seeks to improve the accuracy of the 3D data points obtained through the phase unwrapping process. By applying the k-nearest-neighbor search method, the error bound of the wrapped phase is controlled with improved flexibility. To achieve the desired scanning quality, a series of fringe patterns is generated with multiple phases at three different frequencies. For this method, the pattern is shifted by utilizing a six-step temporal phase unwrapping process. In this unwrapping process, the error bound is controlled by employing the k-nearest-neighbor search method and spatial comparison method to obtain an accurate fringe order. Through our correction method, the wrapped phases can be unwrapped more accurately and thus enhance the robustness of the scanning system compared to previous phase unwrapping methods.

5.
Arch Orthop Trauma Surg ; 138(8): 1165-1172, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29936580

RESUMO

BACKGROUNDS: Impingement is a risk factor for instability and prosthetic failure following total hip arthroplasty (THA). If the periacetabular osteophytes are not removed at surgery, impingement could occur between the osteophytes and the femoral stem following THA. However, excessive removal of the osteophytes could lead to bleeding from the bone. The aim of our study, therefore, was to locate the site of the impingement and to determine the width of tolerable osteophytes, which does not induce impingement during activities of daily living (ADL), using a three-dimensional simulation. METHODS: On 35 hip models, virtual THA was performed. The acetabular cups were positioned at 45° abduction and 20° anteversion, and the anteversion of femoral stems was 15°. Circular osteophytes with a 30-mm rim were built around the acetabular cup. Fourteen ADL motions were simulated, and the osteophytes were removed until there was no impingement. A clock face was used to map the location and the width of tolerable osteophytes. RESULTS: The impingement mainly occurred in antero-superior and posterior portions around the acetabular cup. Only 4.2-6.2-mm osteophytes were tolerable at the antero-superior portion (12-3 o'clock) and 6.3-7.2-mm osteophytes at the posterior portion (8-10 o'clock) following a total hip arthroplasty. In antero-inferior and postero-superior portions, over-20-mm osteophytes did not induce any impingement. CONCLUSION: Osteophytes in the antero-superior and posterior portion of the acetabulum should be excised during a THA to avoid impingement of the femur-stem construct on the acetabular osteophytes during ADLs.


Assuntos
Acetábulo , Artroplastia de Quadril , Simulação por Computador , Impacto Femoroacetabular , Osteófito , Acetábulo/citologia , Acetábulo/patologia , Acetábulo/fisiopatologia , Acetábulo/cirurgia , Impacto Femoroacetabular/patologia , Impacto Femoroacetabular/fisiopatologia , Impacto Femoroacetabular/prevenção & controle , Quadril/patologia , Quadril/fisiopatologia , Quadril/cirurgia , Humanos , Modelos Biológicos , Osteófito/patologia , Osteófito/fisiopatologia
6.
Nat Mater ; 14(7): 701-6, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25915034

RESUMO

Therapeutics based on transcription factors have the potential to revolutionize medicine but have had limited clinical success as a consequence of delivery problems. The delivery of transcription factors is challenging because it requires the development of a delivery vehicle that can complex transcription factors, target cells and stimulate endosomal disruption, with minimal toxicity. Here, we present a multifunctional oligonucleotide, termed DARTs (DNA assembled recombinant transcription factors), which can deliver transcription factors with high efficiency in vivo. DARTs are composed of an oligonucleotide that contains a transcription-factor-binding sequence and hydrophobic membrane-disruptive chains that are masked by acid-cleavable galactose residues. DARTs have a unique molecular architecture, which allows them to bind transcription factors, trigger endocytosis in hepatocytes, and stimulate endosomal disruption. The DARTs have enhanced uptake in hepatocytes as a result of their galactose residues and can disrupt endosomes efficiently with minimal toxicity, because unmasking of their hydrophobic domains selectively occurs in the acidic environment of the endosome. We show that DARTs can deliver the transcription factor nuclear erythroid 2-related factor 2 (Nrf2) to the liver, catalyse the transcription of Nrf2 downstream genes, and rescue mice from acetaminophen-induced liver injury.


Assuntos
DNA/química , Oligonucleotídeos/química , Fatores de Transcrição/metabolismo , Alanina Transaminase/metabolismo , Animais , Sistemas de Liberação de Medicamentos , Endossomos/metabolismo , Células Hep G2 , Hepatócitos/citologia , Humanos , Concentração de Íons de Hidrogênio , Hidrólise , Fígado/metabolismo , Camundongos , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo , Espectrometria de Fluorescência , Distribuição Tecidual
7.
Surg Innov ; 21(1): 80-9, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24145692

RESUMO

Total knee arthroplasty (TKA) is a surgical method for replacing a degenerated or diseased knee joint that can no longer perform daily functions with an artificial knee implant. In TKA, the artificial knee implant should be inserted such that it aligns well with the mechanical axis of the leg. Thus, precise bone cutting is essential. To improve TKA outcomes, a registration process is performed to locate the predetermined bone cutting area by calculating the position and posture of the femur and tibia. In this article, we propose a patient-specific registration guide that is able to significantly reduce registration time and effort without loss of accuracy. Furthermore, the patient-specific registration guide can be implemented with real-time registration, allowing continuous surgical information to be provided without the insertion of any tracking devices. The precision and accuracy of the proposed registration guide were confirmed through animal tests with a digitizer, stereo camera, and linear motion generator. The error of our registration method, including measurement and guide attachment errors, reached a maximum of 0.321 mm for one pair of cow legs.


Assuntos
Artroplastia do Joelho/métodos , Modelos Anatômicos , Cirurgia Assistida por Computador/métodos , Animais , Bovinos , Fêmur/cirurgia , Imageamento Tridimensional , Prótese do Joelho , Imageamento por Ressonância Magnética , Ajuste de Prótese , Reprodutibilidade dos Testes , Tíbia/cirurgia , Tomografia Computadorizada por Raios X
8.
J Phys Ther Sci ; 26(4): 525-8, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24764626

RESUMO

[Purpose] The aim of this study was to present an individualized resistance training method to enable exercise while maintaining an exercise load that is set according to an individual's joint angle-torque using a haptic-based resistance training machine. [Methods] Five participants (machine group) performed individualized shoulder internal and external rotation training with a haptic resistance training machine, while another five participants performed general dumbbell-based shoulder internal and external rotation training for eight weeks. Internal and external rotation powers of subjects were measured using an isokinetic machine before and after training. [Results] The average powers of both shoulder internal and external rotation has been improved after training (25.72%, 13.62%). The improvement in power of external rotation in the machine group was significantly higher than that in the control group. [Conclusion] This study proposes a haptic-based individualized rotator cuff muscle training method. The training protocol maintaining the joint angle-torque profile showed better improvement of shoulder internal/external rotation than dumbbell training.

9.
Investig Clin Urol ; 65(5): 423-434, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39249914

RESUMO

This study aimed to assess the prognostic role of body mass index (BMI) in patients with metastatic renal cell carcinoma (mRCC) treated with first-line immune checkpoint inhibitor (ICI)-based therapy. We searched for relevant studies in the MEDLINE, Embase, and Cochrane Library databases. The initial search yielded 599 records, of which seven articles (2,517 patients) were selected for analysis. Patients with a high BMI had a favorable overall survival (OS) based on hazard ratio (HR) (crude HR 0.69, 95% confidence interval [CI] 0.57-0.83, p<0.0001; adjusted (a)HR 0.75, 95% CI 0.59-0.95, p=0.02), but not relative risk (RR 0.88, 95% CI 0.67-1.16, p=0.37). In the subgroup analysis, patients with a high BMI had better OS in the ICI with tyrosine kinase inhibitor (TKI) subgroup (aHR 0.71, 95% CI 0.55-0.92, p=0.01), while no significant difference was found in the ICI-only subgroup (aHR 1.02, 95% CI 0.56-1.87, p=0.95). Adjusted statistics for progression-free survival (PFS) were assessable in predominantly ICI-only studies and demonstrated a favorable outcome for patients with a low BMI (aHR 1.67, 95% CI 1.14-2.45, p=0.01). In conclusion, the impact of high BMI varies depending on the treatment type, exhibiting a favorable correlation with OS within ICI with TKI subgroup, but indicating an adverse association with PFS in the ICI-only subgroup. Further research is needed to clarify the influence of BMI by stratifying patients into ICI-only and ICI with TKI treatment to provide more insights.


Assuntos
Índice de Massa Corporal , Carcinoma de Células Renais , Inibidores de Checkpoint Imunológico , Neoplasias Renais , Humanos , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/mortalidade , Carcinoma de Células Renais/secundário , Inibidores de Checkpoint Imunológico/uso terapêutico , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/mortalidade , Neoplasias Renais/patologia , Prognóstico , Taxa de Sobrevida , Resultado do Tratamento
10.
Nat Commun ; 15(1): 468, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38212312

RESUMO

Diabetic sensory neuropathy (DSN) is one of the most common complications of type 2 diabetes (T2D), however the molecular mechanistic association between T2D and DSN remains elusive. Here we identify ubiquitin C-terminal hydrolase L1 (UCHL1), a deubiquitinase highly expressed in neurons, as a key molecule underlying T2D and DSN. Genetic ablation of UCHL1 leads to neuronal insulin resistance and T2D-related symptoms in Drosophila. Furthermore, loss of UCHL1 induces DSN-like phenotypes, including numbness to external noxious stimuli and axonal degeneration of sensory neurons in flies' legs. Conversely, UCHL1 overexpression improves DSN-like defects of T2D model flies. UCHL1 governs insulin signaling by deubiquitinating insulin receptor substrate 1 (IRS1) and antagonizes an E3 ligase of IRS1, Cullin 1 (CUL1). Consistent with these results, genetic and pharmacological suppression of CUL1 activity rescues T2D- and DSN-associated phenotypes. Therefore, our findings suggest a complete set of genetic factors explaining T2D and DSN, together with potential remedies for the diseases.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Animais , Resistência à Insulina/genética , Ubiquitina Tiolesterase/genética , Diabetes Mellitus Tipo 2/genética , Drosophila , Neurônios
11.
J Appl Clin Med Phys ; 14(5): 25-42, 2013 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-24036857

RESUMO

Phase-based respiratory-gated radiotherapy relies on the reproducibility of patient breathing during the treatment. To monitor the positional reproducibility of patient breathing against a 4D CT simulation, we developed a real-time motion verification system (RMVS) using an optical tracking technology. The system in the treatment room was integrated with a real-time position management system. To test the system, an anthropomorphic phantom that was mounted on a motion platform moved on a programmed breathing pattern and then underwent a 4D CT simulation with RPM. The phase-resolved anterior surface lines were extracted from the 4D CT data to constitute 4D reference lines. In the treatment room, three infrared reflective markers were attached on the superior, middle, and inferior parts of the phantom along with the body midline and then RMVS could track those markers using an optical camera system. The real-time phase information extracted from RPM was delivered to RMVS via in-house network software. Thus, the real-time anterior-posterior positions of the markers were simultaneously compared with the 4D reference lines. The technical feasibility of RMVS was evaluated by repeating the above procedure under several scenarios such as ideal case (with identical motion parameters between simulation and treatment), cycle change, baseline shift, displacement change, and breathing type changes (abdominal or chest breathing). The system capability for operating under irregular breathing was also investigated using real patient data. The evaluation results showed that RMVS has a competence to detect phase-matching errors between patient's motion during the treatment and 4D CT simulation. Thus, we concluded that RMVS could be used as an online quality assurance tool for phase-based gating treatments.


Assuntos
Neoplasias da Próstata/radioterapia , Planejamento da Radioterapia Assistida por Computador , Técnicas de Imagem de Sincronização Respiratória , Suspensão da Respiração , Tomografia Computadorizada Quadridimensional , Humanos , Masculino , Movimento (Física) , Órgãos em Risco , Imagens de Fantasmas , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia
12.
J Phys Ther Sci ; 25(10): 1299-301, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24259780

RESUMO

The purpose of this study was to investigate the differences in muscle activation patterns of the biceps brachii (BB) and flexor carpi radialis (FCR) muscles, while measuring the resultant force (RF) at different shoulder flexion angles. [Subjects] Thirteen healthy males (age 24.85±3.4 years, weight; 77.8±7.9 kg; height, 1.7±0.05 m) were enrolled in this study. [Methods] The resultant force was measured by a force transducer . The elbow angle remained constant and the flexion shoulder angle was changed (30°, 45°, 60°, 75° and 90°). [Results] The results of the surface EMG show the largest muscle activities occurred at a shoulder flexion of 75° for BB and 90° for FCR. The largest resultant force was measured at a shoulder flexion angle of 75°. We conclude, that when performing the biceps curl exercise using an arm curl machine, the shoulder should be flexed at 75° to maximize the focus of the exercise for the BB. [Conclusion] These results are useful from the perspective of design as they highlight the differences in the muscle activation of BB and FCR with postural change. Ultimately this knowledge can be used in the design of rehabilitation training for the shoulder as they show that posture can affect muscle activation.

13.
J Control Release ; 354: 188-195, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36596342

RESUMO

Gene therapy approaches that utilize Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) ribonucleases have tremendous potential to treat human disease. However, CRISPR therapies delivered by integrating viral vectors are limited by potential off-target genome editing caused by constitutive activation of ribonuclease functions. Thus, biomaterial formulations are being used for the delivery of purified CRISPR components to increase the efficiency and safety of genome editing approaches. We previously demonstrated that a novel peptide identified by phage display, TAxI-peptide, mediates delivery of recombinant proteins into neurons. In this report we utilized NeutrAvidin protein to formulate neuron-targeted genome-editing nanoparticles. Cas12a ribonucleases was loaded with biotinylated guide RNA and biotinylated TAxI-peptide onto NeutrAvidin protein to coordinate the formation a targeted ribonuclease protein (RNP) complex. TAxI-RNP complexes are polydisperse with a 14.3 nm radius. The nanoparticles are stable after formulation and show good stability in the presence of normal mouse serum. TAxI-RNP nanoparticles increased neuronal delivery of Cas12a in reporter mice, resulting in induced tdTomato expression after direct injection into the dentate gyrus of the hippocampus. TAxI-RNP nanoparticles also increased genome editing efficacy in hippocampal neurons versus glia. These studies demonstrate the ability to assemble RNP nanoformulations with NeutrAvidin by binding biotinylated peptides and gRNA-loaded Cas12a ribonucleases into protein nanoparticles that target CRISPR delivery to specific cell-types in vivo. The potential to deliver CRISPR nanoparticles to specific cell-types and control off-target delivery to further reduce deleterious genome editing is essential for the creation of viable therapies to treat nervous system disease.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Camundongos , Animais , Humanos , Edição de Genes/métodos , Ribonucleases , Peptídeos , Neurônios
14.
Adv Drug Deliv Rev ; 200: 115026, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37516409

RESUMO

The field of gene editing has received much attention in recent years due to its immense therapeutic potential. In particular, gene editing therapeutics, such as the CRISPR-Cas systems, base editors, and other emerging gene editors, offer the opportunity to address previously untreatable disorders. This review aims to summarize the therapeutic applications of gene editing based on mRNA delivery. We introduce gene editing therapeutics using mRNA and focus on engineering and improvement of gene editing technology. We subsequently examine ex vivo and in vivo gene editing techniques and conclude with an exploration of the next generation of CRISPR and base editing systems.


Assuntos
Edição de Genes , Técnicas de Transferência de Genes , Humanos , Edição de Genes/métodos , RNA Mensageiro/genética , Sistemas CRISPR-Cas , Terapia Genética/métodos
15.
Front Mol Biosci ; 10: 1330400, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38234582

RESUMO

Extracellular vesicles (EVs) are membrane-enclosed particles secreted by a variety of cell types. These vesicles encapsulate a diverse range of molecules, including proteins, nucleic acids, lipids, metabolites, and even organelles derived from their parental cells. While EVs have emerged as crucial mediators of intercellular communication, they also hold immense potential as both biomarkers and therapeutic agents for numerous diseases. A thorough understanding of EV biogenesis is crucial for the development of EV-based diagnostic developments since the composition of EVs can reflect the health and disease status of the donor cell. Moreover, when EVs are taken up by target cells, they can exert profound effects on gene expression, signaling pathways, and cellular behavior, which makes these biomolecules enticing targets for therapeutic interventions. Yet, despite decades of research, the intricate processes underlying EV biogenesis by donor cells and subsequent uptake by recipient cells remain poorly understood. In this review, we aim to summarize current insights and advancements in the biogenesis and uptake mechanisms of EVs. By shedding light on the fundamental mechanisms governing EV biogenesis and delivery, this review underscores the potential of basic mechanistic research to pave the way for developing novel diagnostic strategies and therapeutic applications.

16.
Med Phys ; 38(6): 3006-12, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21815374

RESUMO

PURPOSE: Optical image-guided systems (e.g., AlignRT, frameless SonArray, ExacTrac) have been used with advantages of avoiding excessive radiation exposure and real-time patient monitoring. Although these systems showed proven accuracy, they need to modify a full facemask for patients with H&N cancer and brain tumor. We developed an optical-based guidance system to manage interfractional and intrafractional setup errors by tracking external markers behind a full facemask. METHODS: Infra-red (IR) reflecting markers were attached on the face of a head phantom and then the phantom was immobilized by a full face thermoplastic mask. A stereo camera system consisting of two CCD cameras was mounted on the inferior wall of treatment room. The stereo camera system was calibrated to reconstruct 3D coordinates of multiple markers with respect to the isocenter using the direct linear transform (DLT) algorithm. The real-time position of the phantom was acquired, through the stereo camera system, by detecting the IR markers behind the full facemask. The detection errors with respect to the reference positions of planning CT images were calculated in six degrees of freedom (6-DOF) by a rigid-body registration technique. RESULTS: The calibration accuracy of the system was in submillimeter (0.33 mm +/- 0.27 mm), which was comparable to others. The mean distance between each of marker positions of optical images and planning CT images was 0.50 mm +/- 0.67 mm. The maximum deviations of 6-DOF registration were less than 1 mm and 1 degrees for the couch translation and rotation, respectively. CONCLUSIONS: The developed system showed the accuracy and consistency comparable to the commercial optical guided systems, while allowing us to simultaneously immobilize patients with a full face thermoplastic mask.


Assuntos
Fenômenos Ópticos , Proteção Radiológica/instrumentação , Radioterapia Assistida por Computador/instrumentação , Calibragem , Marcadores Fiduciais , Humanos , Imageamento Tridimensional , Imagens de Fantasmas , Proteção Radiológica/normas , Radioterapia Assistida por Computador/normas , Radioterapia de Intensidade Modulada , Tomografia Computadorizada por Raios X
17.
Med Phys ; 38(6): 3114-24, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21815385

RESUMO

PURPOSE: To introduce a respiratory motion management technique, so called quasi-breath-hold (QBH) technique and evaluate its feasibility. As a hybrid technique combining free-breathing-based gating (denoted as gating for convenience) and breath-hold (BH), the QBH is designed to overcome typical limitations existing in either one such as phase-shift, residual motion, complexity, and discomfort. METHODS: The QBH is realized using an audio-visual biofeedback system (AVBFS) and a respiratory motion management program (RMMP). The AVBFS, consisting of two infra-red stereo cameras and a head mounted display, monitors respiratory motion and provides dynamic feedback to patients. The RMMP establishes a personalized respiration model based on deep free breathing. The model is further processed to generate a QBH model by inserting a short breath-hold period into the end point of the-end-of-expiration phase. Then the patient is guided to follow the QBH model through the AVBFS. A simulation study with ten volunteers was performed to evaluate the feasibility of the proposed technique. In the simulation, an in-house developed macro program automatically controlled the QBH procedure to virtually deliver an intensity modulated radiation therapy (IMRT) plan. For each volunteer subject, three QBH maneuvers with different breath-hold times of 3, 5, and 7s (denoted as QBH3s, QBH5s, and QBH7s, respectively) and a conventional gating maneuver with 30% duty cycle (for comparison purpose) were applied. External respiration motion signals obtained during the gating window were analyzed to obtain mean absolute error (MAE) between the measured and guiding curve, mean absolute deviation (MAD) of the measured curve, and an inverse uncertainty time histogram (IUTH). RESULTS: Every volunteer successfully performed all of the four maneuvers (1 gating and 3 QBH patterns). The average treatment times were 466.8, 452.3, and 430.8 s for the QBH3s, QBH5s, and QBH7s, respectively, compared to 530.4 s for the gating technique. The mean absolute errors between measured and guiding curve during the gating window were 0.9 +/- 0.7, 0.8 +/- 0.6, 0.7 +/- 0.6, and 0.6 +/- 0.7 mm for the gating, QBH3s, QBH5s, and QBH7s, respectively. The mean absolute deviations of the measured curve during the gating window were 0.7 +/- 0.7, 0.5 +/- 0.5, 0.5 +/- 0.4, and 0.5 +/- 0.6 mm for the gating, QBH3s, QBH5s, and QBH7s, respectively. In the analysis of the IUTH during the gating window, the QBH simulations showed similar (QBH3s) or less (QBH5s and QBH7s) motion uncertainties compared to the gating simulation. CONCLUSIONS: The proposed QBH technique with personalized audio-visual biofeedback was feasible for respiratory motion management. It showed equivalent or less motion uncertainty and shorter treatment time than the conventional free-breathing-based gating technique did. The technique is expected to optimally compromise between patient comfort and treatment efficiency.


Assuntos
Retroalimentação Sensorial , Movimento , Radioterapia/métodos , Respiração , Adulto , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Incerteza , Adulto Jovem
18.
Appl Ergon ; 75: 263-271, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30509535

RESUMO

This study proposes an ingress/egress discomfort prediction algorithm using an in-depth biomechanical method and motion capture database. The ingress/egress motion of the subject was captured using an optical motion capture system and physically adjustable vehicle mock-up. The subjective discomfort evaluation data were also recorded at the same time. The inverse kinematics and inverse dynamics were performed to analyze captured ingress/egress motion. These procedure provide motion and joint torque information on each subject. Based on the analysis results, this study proposes the following novel features: accumulated movement of joint and sum of rectified joint torque. This study conducted a feature selection procedure to identify a relevant feature subset. Recursive feature selection and optimal feature selection methods found the most relevant feature subset with collected subjective responses. Finally, we constructed the prediction model using support vector machine. The prediction model was evaluated through prediction accuracy and statistical analysis. For comparison with the previous study, this study implemented two representative models and compare the result with those of the previous studies using the identical dataset. The effectiveness of proposed algorithm was demonstrated in comparison with previous studies.


Assuntos
Algoritmos , Desenho de Equipamento/psicologia , Ergonomia/métodos , Veículos Automotores , Adulto , Fenômenos Biomecânicos , Bases de Dados Factuais , Feminino , Humanos , Masculino , Movimento (Física) , Movimento , Dispositivos Ópticos , Máquina de Vetores de Suporte , Torque , Adulto Jovem
19.
J Biomech ; 84: 27-35, 2019 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-30558910

RESUMO

Due to the increased availability of digital human models, the need for knowing human movement is important in product design process. If the human motion is derived rapidly as design parameters change, a developer could determine the optimal parameters. For example, the optimal design of the door panel of an automobile can be obtained for a human operator to conduct the easiest ingress and egress motion. However, acquiring motion data from existing methods provides only unrealistic motion or requires a great amount of time. This not only leads to an increased time consumption for a product development, but also causes inefficiency of the overall design process. To solve such problems, this research proposes an algorithm to rapidly and accurately predict full-body human motion using an artificial neural network (ANN) and a motion database, as the design parameters are varied. To achieve this goal, this study refers to the processes behind human motor learning procedures. According to the previous research, human generate new motion based on past motion experience when they encounter new environments. Based on this principle, we constructed a motion capture database. To construct the database, motion capture experiments were performed in various environments using an optical motion capture system. To generate full-body human motion using this data, a generalized regression neural network (GRNN) was used. The proposed algorithm not only guarantees rapid and accurate results but also overcomes the ambiguity of the human motion objective function, which has been pointed out as a limitation of optimization-based research. Statistical criteria were utilized to confirm the similarity between the generated motion and actual human motion. Our research provides the basis for a rapid motion prediction algorithm that can include a variety of environmental variables. This research contributes to an increase in the usability of digital human models, and it can be applied to various research fields.


Assuntos
Movimento , Redes Neurais de Computação , Algoritmos , Automóveis , Bases de Dados Factuais , Humanos , Dispositivos Ópticos
20.
Curr Opin Biotechnol ; 52: 25-31, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29486392

RESUMO

Protein therapeutics based on transcription factors, gene editing enzymes, signaling proteins and protein antigens, have the potential to provide cures for a wide number of untreatable diseases, but cannot be developed into therapeutics due to challenges in delivering them into the cytoplasm. There is therefore great interest in developing strategies that can enable proteins to enter the cytoplasm of cells. In this review article we will discuss recent progress in intracellular protein therapeutics, which are focused on the following four classes of therapeutics, Firstly, vaccine development, secondly, transcription factor therapies, thirdly, gene editing and finally, cancer therapeutics. These exciting new advances raise the prospect of developing cures for several un-treatable diseases.


Assuntos
Espaço Intracelular/metabolismo , Proteínas/metabolismo , Genoma , Humanos , Neoplasias/metabolismo , Neoplasias/terapia , Fatores de Transcrição/metabolismo , Vacinas/metabolismo
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