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1.
Phys Rev Lett ; 132(18): 186001, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38759199

RESUMO

The kagome materials AV_{3}Sb_{5} (A=K, Rb, Cs) host an intriguing interplay between unconventional superconductivity and charge-density waves. Here, we investigate CsV_{3}Sb_{5} by combining high-resolution thermal-expansion, heat-capacity, and electrical resistance under strain measurements. We directly unveil that the superconducting and charge-ordered states strongly compete, and that this competition is dramatically influenced by tuning the crystallographic c axis. In addition, we report the absence of additional bulk phase transitions within the charge-ordered state, notably associated with rotational symmetry breaking within the kagome planes. This suggests that any breaking of the C_{6} invariance occurs via different stacking of C_{6}-symmetric kagome patterns. Finally, we find that the charge-density-wave phase exhibits an enhanced A_{1g}-symmetric elastoresistance coefficient, whose large increase at low temperature is driven by electronic degrees of freedom.

2.
Phys Rev Lett ; 130(10): 106904, 2023 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-36962049

RESUMO

Ta_{2}NiSe_{5} is an excitonic insulator candidate showing the semiconductor or semimetal-to-insulator (SI) transition below T_{c}=326 K. However, since a structural transition accompanies the SI transition, deciphering the role of electronic and lattice degrees of freedom in driving the SI transition has remained controversial. Here, we investigate the photoexcited nonequilibrium state in Ta_{2}NiSe_{5} using pump-probe Raman and photoluminescence spectroscopies. The combined nonequilibrium spectroscopic measurements of the lattice and electronic states reveal the presence of a photoexcited metastable state where the insulating gap is suppressed, but the low-temperature structural distortion is preserved. We conclude that electron correlations play a vital role in the SI transition of Ta_{2}NiSe_{5}.

3.
J Surg Orthop Adv ; 32(2): 111-113, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37668648

RESUMO

Our study examined whether risk of revision for aseptic loosening following cemented total knee arthroplasty (TKA) is (1) increased with tourniquetless surgery and (2) affected by patient characteristics or surgical factors. Primary cemented TKAs from 2005-2012 with 2-year follow up were analyzed (n = 5,508 with tourniquet; n=101 without). Revision for aseptic loosening was compared between TKA performed with and without a tourniquet. Patient characteristics were recorded. At mean 4.8-year follow up, risk of aseptic loosening was similar between TKA performed with or without a tourniquet (p = 0.3151). Aseptic loosening was more likely in men (p = 0.0018) and patients younger than 50 (p < 0.0001). No difference was observed between cruciate-retaining and posterior-stabilized implants (p = 0.1250). With the numbers available for study, we did not observe an increased risk of aseptic loosening with tourniquetless cemented primary TKA. Patients younger than 50, particularly men, should be counselled on the increased risk of TKA revision for aseptic loosening. (Journal of Surgical Orthopaedic Advances 32(2):111-113, 2023).


Assuntos
Artroplastia do Joelho , Falha de Prótese , Humanos , Torniquetes , Reoperação
4.
Hepatology ; 69(2): 760-773, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-29357190

RESUMO

Current blood biomarkers are suboptimal in detecting drug-induced liver injury (DILI) and predicting its outcome. We sought to characterize the natural variabilty and performance characteristics of 14 promising DILI biomarker candidates. Serum or plasma from multiple cohorts of healthy volunteers (n = 192 and n = 81), subjects who safely took potentially hepatotoxic drugs without adverse effects (n = 55 and n = 92) and DILI patients (n = 98, n = 28, and n = 143) were assayed for microRNA-122 (miR-122), glutamate dehydrogenase (GLDH), total cytokeratin 18 (K18), caspase cleaved K18, glutathione S-transferase α, alpha-fetoprotein, arginase-1, osteopontin (OPN), sorbitol dehydrogenase, fatty acid binding protein, cadherin-5, macrophage colony-stimulating factor receptor (MCSFR), paraoxonase 1 (normalized to prothrombin protein), and leukocyte cell-derived chemotaxin-2. Most candidate biomarkers were significantly altered in DILI cases compared with healthy volunteers. GLDH correlated more closely with gold standard alanine aminotransferase than miR-122, and there was a surprisingly wide inter- and intra-individual variability of miR-122 levels among healthy volunteers. Serum K18, OPN, and MCSFR levels were most strongly associated with liver-related death or transplantation within 6 months of DILI onset. Prediction of prognosis among DILI patients using the Model for End-Stage Liver Disease was improved by incorporation of K18 and MCSFR levels. Conclusion: GLDH appears to be more useful than miR-122 in identifying DILI patients, and K18, OPN, and MCSFR are promising candidates for prediction of prognosis during an acute DILI event. Serial assessment of these biomarkers in large prospective studies will help further delineate their role in DILI diagnosis and management.


Assuntos
Biomarcadores/sangue , Doença Hepática Induzida por Substâncias e Drogas/sangue , Adulto , Estudos de Casos e Controles , Doença Hepática Induzida por Substâncias e Drogas/diagnóstico , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico
5.
Small ; 15(34): e1902353, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31257719

RESUMO

The discovery of the high maximum energy product of 59 MGOe for NdFeB magnets is a breakthrough in the development of permanent magnets with a tremendous impact in many fields of technology. This value is still the world record, for 40 years. This work reports on a reliable and robust route to realize nearly perfectly ordered L10 -phase FePt nanoparticles, leading to an unprecedented energy product of 80 MGOe at room temperature. Furthermore, with a 3 nm Au coverage, the magnetic polarization of these nanomagnets can be enhanced by 25% exceeding 1.8 T. This exceptional magnetization and anisotropy is confirmed by using multiple imaging and spectroscopic methods, which reveal highly consistent results. Due to the unprecedented huge energy product, this material can be envisaged as a new advanced basic magnetic component in modern micro and nanosized devices.

6.
Gut ; 66(6): 1154-1164, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28341748

RESUMO

Idiosyncratic drug-induced liver injury (IDILI) is a rare but potentially severe adverse drug reaction that should be considered in patients who develop laboratory criteria for liver injury secondary to the administration of a potentially hepatotoxic drug. Although currently used liver parameters are sensitive in detecting DILI, they are neither specific nor able to predict the patient's subsequent clinical course. Genetic risk assessment is useful mainly due to its high negative predictive value, with several human leucocyte antigen alleles being associated with DILI. New emerging biomarkers which could be useful in assessing DILI include total keratin18 (K18) and caspase-cleaved keratin18 (ccK18), macrophage colony-stimulating factor receptor 1, high mobility group box 1 and microRNA-122. From the numerous in vitro test systems that are available, monocyte-derived hepatocytes generated from patients with DILI show promise in identifying the DILI-causing agent from among a panel of coprescribed drugs. Several computer-based algorithms are available that rely on cumulative scores of known risk factors such as the administered dose or potential liabilities such as mitochondrial toxicity, inhibition of the bile salt export pump or the formation of reactive metabolites. A novel DILI cluster score is being developed which predicts DILI from multiple complimentary cluster and classification models using absorption-distribution-metabolism-elimination-related as well as physicochemical properties, diverse substructural descriptors and known structural liabilities. The provision of more advanced scientific and regulatory guidance for liver safety assessment will depend on validating the new diagnostic markers in the ongoing DILI registries, biobanks and public-private partnerships.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/diagnóstico , Doença Hepática Induzida por Substâncias e Drogas/genética , Alanina Transaminase/sangue , Algoritmos , Fosfatase Alcalina/sangue , Animais , Aspartato Aminotransferases/sangue , Autoanticorpos/sangue , Bilirrubina/sangue , Biomarcadores/sangue , Células Cultivadas , Doença Hepática Induzida por Substâncias e Drogas/sangue , Simulação por Computador , Testes Genéticos , Antígenos HLA/genética , Hepatócitos/efeitos dos fármacos , Humanos , Queratina-18/sangue , MicroRNAs/sangue , Modelos Biológicos , Valor Preditivo dos Testes , Medição de Risco
7.
Phys Rev Lett ; 116(23): 237003, 2016 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-27341252

RESUMO

The iron-based superconductors AFe_{2}As_{2} with A=K, Rb, Cs exhibit large Sommerfeld coefficients approaching those of heavy-fermion systems. We have investigated the magnetostriction and thermal expansion of this series to shed light on this unusual behavior. Quantum oscillations of the magnetostriction allow identifying the band-specific quasiparticle masses which by far exceed the band-structure derived masses. The divergence of the Grüneisen ratio derived from thermal expansion indicates that with increasing volume along the series a quantum critical point is approached. The critical fluctuations responsible for the enhancement of the quasiparticle masses appear to weaken the superconducting state.

8.
Appl Microbiol Biotechnol ; 100(17): 7499-515, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27037692

RESUMO

Nowadays, general and specific aminopeptidases are of great interest, especially for protein hydrolysis in the food industry. As shown previously, it is confirmed that the general aminopeptidase N (PepN; EC 3.4.11.2) and the proline-specific peptidase PepX (EC 3.4.14.11) from Lactobacillus helveticus ATCC 12046 show a synergistic effect during protein hydrolysis which results in high degrees of hydrolysis and reduced bitterness. To combine both activities, the enzymes were linked and a fusion protein called PepN-L1-PepX (FUS-PepN-PepX) was created. After production and purification, the fusion protein was characterized. Some of its biochemical characteristics were altered in favor for an application compared to the single enzymes. As an example, the optimum temperature for the PepN activity increased from 30 °C for the single enzyme to 35 °C for FUS-PepN. In addition, the temperature stability of PepX was higher for FUS-PepX than for the single enzyme (50 % compared to 40 % residual activity at 50 °C after 14 days, respectively). In addition, the disulfide bridge-reducing reagent ß-mercaptoethanol did not longer inactivate the FUS-PepN activity. Furthermore, the K M values decreased for both enzyme activities in the fusion protein. Finally, it was found that the synergistic hydrolysis performance in a casein hydrolysis was not reduced for the fusion protein. The increase of the relative degree of hydrolysis of a prehydrolyzed casein solution was the same as it was for the single enzymes. As a benefit, the resulting hydrolysate showed a strong antioxidative capacity (ABTS-IC50 value: 5.81 µg mL(-1)).


Assuntos
Aminopeptidases/genética , Proteínas de Bactérias/genética , Caseínas/metabolismo , Dipeptidil Peptidases e Tripeptidil Peptidases/genética , Lactobacillus helveticus/enzimologia , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Aminopeptidases/metabolismo , Antioxidantes/metabolismo , Proteínas de Bactérias/metabolismo , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Indústria Alimentícia , Hidrólise , Lactobacillus helveticus/genética , Lactobacillus helveticus/metabolismo , Mercaptoetanol/química
9.
J Sci Food Agric ; 96(10): 3358-64, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26526345

RESUMO

BACKGROUND: Due to allergies or other health disorders a certain segment of the population is not able to safely consume some plant proteins, which are the main protein support in human nutrition. Coeliac disease is a prominent autoimmune disorder and requires a strict adherence to a gluten-free diet. The aim of this study was to identify suitable combinations of enzymatic hydrolysis and common unit operations in food processing (centrifugation, ultra-filtration) to produce gluten-free wheat gluten hydrolysates for food application. To analyse the hydrolysates, a simple and cheap competitive ELISA protocol was designed and validated in this study as well. RESULTS: The competitive ELISA was validated using gliadin spiked skim milk protein hydrolysates, due to the latter application of the assay. The limit of quantification was 4.19 mg kg(-1) , which allowed the identification of gluten-free (<20 mg kg(-1) ) hydrolysates. Enzymatic hydrolysis, including the type of peptidase, and the downstream processing greatly affected the antigenicity of the hydrolysates. CONCLUSION: Enzymatic hydrolysis and downstream processing operations, such as centrifugation and ultra-filtration, reduced the antigenicity of wheat gluten hydrolysates. Gluten-free hydrolysates were obtained with Flavourzyme after centrifugation (25 g L(-1) substrate) and after 1 kDa ultra-filtration (100 g L(-1) substrate). A multiple peptidase complex, such as Flavourzyme, seems to be required for the production of gluten-free hydrolysates. © 2015 Society of Chemical Industry.


Assuntos
Antígenos de Plantas/análise , Manipulação de Alimentos/métodos , Glutens/imunologia , Peptídeo Hidrolases/metabolismo , Triticum/química , Alérgenos/análise , Doença Celíaca/dietoterapia , Centrifugação , Dieta Livre de Glúten , Ensaio de Imunoadsorção Enzimática/métodos , Gliadina/análise , Glutens/química , Glutens/metabolismo , Humanos , Hidrólise , Proteínas de Plantas/imunologia , Ultrafiltração
10.
J Pharmacol Exp Ther ; 355(2): 145-51, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26330539

RESUMO

The somatostatin analog octreotide can lead to hyperbilirubinemia without evidence of liver injury. Here we investigate whether octreotide inhibits the main sinusoidal/canalicular bilirubin carriers and whether it is a transport substrate. Octreotide showed the most potent inhibitory effect toward OATP1B1-mediated transport and weaker inhibition for OATP1B3- and MRP2-mediated transport. Octreotide had no effect on OATP2B1-mediated transport. Octreotide inhibited [(3)H]estradiol-17-ß-glucuronide (E17ßG) influx mediated by OATP1B1, 1B3, and multidrug resistance-associated protein 2 (MRP2) in a concentration-dependent manner, and the IC50 values were computed to be 23 µM (95% confidence interval [CI] 18-29), 68 µM (95% CI 50-91), and 116.6 µM (95% CI 74.5-182.4), respectively. The interaction between octreotide and OATP1B1 was further studied. Inhibition of [(3)H]E17ßG OATP1B1-mediated transport was purely competitive with no changes in maximum transport capacity (Vmax) and a twofold Km increase when the influx kinetics of [(3)H]E17ßG were measured in the presence of octreotide (8.8 ± 3.1 versus 4.4 ± 1.2 µM, P = 0.03). The inhibition constant (Ki) of octreotide for the transport of [(3)H]E17ßG was calculated at 33.5 ± 5.5 µM. Uptake of radiolabeled octreotide by OATP1B1-CHO cells was higher than in wild-type CHO cells and nonlabeled octreotide at the extracellular compartment was able to trans-stimulate the OATP1B1-mediated efflux of intracellular [(3)H]E17ßG, suggesting that octreotide is a substrate of OATP1B1. In summary, this study shows interaction of octreotide on the human hepatocellular bilirubin transporters OATP1B1, OATP1B3, and MRP2, notably OATP1B1. These findings are in line with the clinical observation that a fraction of patients under treatment with octreotide exhibit hyperbilirubinemia.


Assuntos
Subfamília B de Transportador de Cassetes de Ligação de ATP/antagonistas & inibidores , Bilirrubina/metabolismo , Octreotida/efeitos adversos , Transportadores de Ânions Orgânicos Sódio-Independentes/antagonistas & inibidores , Transportadores de Ânions Orgânicos/antagonistas & inibidores , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Animais , Canalículos Biliares/metabolismo , Transporte Biológico , Células CHO , Cricetulus , Estradiol/análogos & derivados , Estradiol/metabolismo , Células HEK293 , Humanos , Transportador 1 de Ânion Orgânico Específico do Fígado , Octreotida/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Dependentes de Sódio/antagonistas & inibidores , Transportadores de Ânions Orgânicos Dependentes de Sódio/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Células Sf9 , Membro 1B3 da Família de Transportadores de Ânion Orgânico Carreador de Soluto , Spodoptera , Sulfotransferases/metabolismo , Simportadores/antagonistas & inibidores , Simportadores/metabolismo , Membro 4 da Subfamília B de Transportadores de Cassetes de Ligação de ATP
11.
Chemphyschem ; 16(2): 428-35, 2015 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-25384350

RESUMO

The kinetics of photodegradation and the reactivity of different sites of the low-band-gap polymers poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b']dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (C-PCPDTBT) and poly[2,6-(4,4-bis-(2-ethylhexyl)dithieno[3,2-b:2',3'-d]silole)-alt-4,7-(2,1,3-benzothiadiazole)] (Si-PCPDTBT) are investigated as thin films and are compared to those of poly(3-hexylthiophene) (P3HT). The decay kinetics are monitored with UV/Vis spectroscopy and the reactivity and product evolution are investigated with X-ray photoelectron spectroscopy (XPS). Both polymers exhibit higher stability than P3HT. The bridging atom in the cyclopentadithiophene (CPDT) subunit has a significant influence on the stability. Varying oxidation rates for the different elements were observed. In the case of Si-PCPDTBT, the silicon atom is oxidized primarily, whereas the photooxidation rates of the other elements are reduced relative to C-PCPDTBT. Additionally, XPS experiments with varying excitation energies reveal a significant reaction gradient within a few nanometers of the surface of degraded thin films of C-PCPDTBT.

12.
J Chem Phys ; 142(10): 101918, 2015 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-25770507

RESUMO

The electronic structure of the interface between cobalt phthalocyanine (CoPc) and epitaxially grown manganese oxide (MnO) thin films is studied by means of photoemission (PES) and X-ray absorption spectroscopy (XAS). Our results reveal a flat-lying adsorption geometry of the molecules on the oxide surface which allows a maximal interaction between the π-system and the substrate. A charge transfer from MnO, in particular, to the central metal atom of CoPc is observed by both PES and XAS. The change of the shape of N-K XAS spectra at the interface points, however, to the involvement of the Pc macrocycle in the charge transfer process. As a consequence of the charge transfer, energetic shifts of MnO related core levels were observed, which are discussed in terms of a Fermi level shift in the semiconducting MnO films due to interface charge redistribution.

13.
J Dairy Sci ; 98(6): 3665-78, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25864053

RESUMO

A selected number of enzymes have recently been assigned to the emerging class of cellobiose 2-epimerases (CE). All CE convert lactose to the rare sugar epilactose, which is regarded as a new prebiotic. Within this study, the gene products of 2 potential CE genes originating from the mesophilic bacteria Cellulosilyticum lentocellum and Dysgonomonas gadei were recombinantly produced in Escherichia coli and purified by chromatography. The enzymes have been identified as novel CE by sequence analysis and biochemical characterizations. The biochemical characterizations included the determination of the molecular weight, the substrate spectrum, and the kinetic parameters, as well as the pH and temperature profiles in buffer and food matrices. Both identified CE epimerize cellobiose and lactose into the C2 epimerization products glucosylmannose and epilactose, respectively. The epimerization activity for lactose was maximal at pH 8.0 or 7.5 and 40°C in defined buffer systems for the CE from C. lentocellum and the CE from D. gadei, respectively. In addition, biotransformations of the foodstuff milk ultrafiltrate containing lactose were demonstrated. The CE from D. gadei was produced in a stirred-tank reactor (12 L) and purified using an automatic system. Enzyme production and purification in this scale indicates that a future upscaling of CE production is possible. The bioconversions of lactose in milk ultrafiltrate were carried out either in a batch process or in a continuously operated enzyme membrane reactor (EMR) process. Both processes ran at an industrially relevant low temperature of 8°C to reduce undesirable microbial growth. The enzyme was reasonably active at the low process temperature because the CE originated from a mesophilic organism. An epilactose yield of 29.9% was achieved in the batch process within 28 h of operation time. In the continuous EMR process, the epilactose yield in the product stream was lower, at 18.5%. However, the enzyme productivity was approximately 6 times higher because the continuous epilactose formation was carried out for about 6 d without further addition of biocatalyst. Within this time, 24g of epilactose in 2.8 L of permeate were produced. The batch and the EMR process showed that the milk ultrafiltrate, which is a sidestream of the milk protein production, might be upgraded to a dairy product of higher value by the enzymatic in situ production of epilactose.


Assuntos
Bactérias/enzimologia , Carboidratos Epimerases/metabolismo , Lactose/química , Leite/química , Animais , Carboidratos Epimerases/genética , Cinética , Prebióticos , Temperatura
14.
J Pediatr Orthop ; 35(8): 816-20, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25526584

RESUMO

BACKGROUND: Percutaneous in situ single screw fixation is the preferred treatment for stable and unstable slipped capital femoral epiphysis (SCFE). The recommended screw placement is in the center of the epiphysis and perpendicular to the physis, which necessitates an anterior starting point for most SCFEs. A recent clinical study has shown good clinical results with a laterally based screw for SCFE, which is oblique to the physis. We sought to biomechanically compare these 2 techniques for load to failure and hypothesized that the laterally based oblique screw is equivalent or superior to an anteriorly based perpendicular screw. METHODS: Twenty-two paired immature porcine femurs were used to compare the techniques. A SCFE model was created in all femurs using a previously published technique by performing a 30-degree posterior closing wedge osteotomy through the proximal physis. In the control group, a screw was placed perpendicular to the slip with an anterior starting point. In the experimental group, the screw was started as close to the mid-lateral cortex of the proximal femur as possible while maintaining the screw anterior to the posterior cortex of the femoral neck and ending at the apex of the epiphysis ignoring the resultant angle to the physis for the experimental group. The specimens were then potted and loaded in a physiologically relevant posteroinferior direction (30 degrees posterior from vertical) to determine load to failure (N) and stiffness (N/mm). RESULTS: No statistical difference was found between the 2 groups in maximum load to failure or stiffness (P>0.05). CONCLUSIONS: A laterally based screw oblique to the physis for in situ fixation in mild SCFE is not significantly different than an anteriorly based screw perpendicular to the physis in load to failure and stiffness in our study model. CLINICAL RELEVANCE: In light of no difference in load to failure of these 2 constructs, surgeons may be more comfortable with the traditional lateral entry point while still aiming for screw placement in the center of head.


Assuntos
Parafusos Ósseos , Cabeça do Fêmur/cirurgia , Procedimentos Ortopédicos , Escorregamento das Epífises Proximais do Fêmur/cirurgia , Animais , Fenômenos Biomecânicos , Modelos Animais de Doenças , Lâmina de Crescimento/cirurgia , Articulação do Quadril/cirurgia , Modelos Anatômicos , Procedimentos Ortopédicos/instrumentação , Procedimentos Ortopédicos/métodos , Suínos
15.
J Arthroplasty ; 29(7): 1423-5, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24581896

RESUMO

Osteotomies of the proximal femur and proximal tibia in revision arthroplasty are well described while guidelines for distal femoral osteotomy are limited. Femoral stems are used with increasing frequency for fixation of revision components in knee arthroplasty and their removal is technically challenging particularly in the setting of infection. We describe a technique of anterior distal femoral osteotomy for revision knee arthroplasty to assist with removal of well-fixed long stemmed cemented or porous femoral components, as well as debridement of infection while preserving bone stock and soft tissue attachments.


Assuntos
Artroplastia do Joelho/métodos , Fêmur/cirurgia , Osteotomia/métodos , Reoperação/métodos , Artroplastia do Joelho/efeitos adversos , Humanos , Procedimentos Cirúrgicos Operatórios/métodos , Tíbia/cirurgia
16.
Expert Opin Drug Saf ; 23(4): 527-537, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38482670

RESUMO

BACKGROUND: Management of side effects in clinical trials has to balance generation of meaningful data with risk for patients. A toxicity area requiring detailed management guidelines is drug-induced liver injury (DILI). In oncology trials, patients are often included despite baseline liver test abnormalities, for whom there is no consensus yet on levels of liver test changes that should trigger action, such as drug interruption or discontinuation. METHODS: We provide an innovative approach to manage hepatocellular DILI in oncology trials for patients with abnormal baseline alanine aminotransferase (ALT) levels. The algorithm proposed is based on mathematical derivation of action thresholds from those generally accepted for patients with normal baselines. RESULTS: The resulting algorithm is grouped by level of baseline abnormality and avoids calculation of baseline multiples. Suggested layered action levels are 4, 6, and 11 × Upper Limit of Normal (ULN) for patients with baseline ALT between 1.5 and 3 × ULN, and 6, 8, and 12 × ULN for patients with baseline ALT between 3 and 5 × ULN, respectively. CONCLUSIONS: Our concept and resulting algorithm are consistent, transparent, and easy to follow, and the method for derivation from consensus-based thresholds may also be applicable to other drug toxicity areas.


Assuntos
Carcinoma Hepatocelular , Doença Hepática Induzida por Substâncias e Drogas , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Neoplasias Hepáticas , Humanos , Neoplasias Hepáticas/tratamento farmacológico , Doença Hepática Induzida por Substâncias e Drogas/diagnóstico , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Alanina Transaminase , Fígado
18.
Anal Bioanal Chem ; 405(14): 4895-904, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23494276

RESUMO

The chemical transformation of the polar chloroaluminum phthalocyanine, AlClPc, to µ-(oxo)bis(phthalocyaninato)aluminum(III), (PcAl)2O, in thin films on indium tin oxide is studied and its influence on the molecular orientation is discussed. The studies were conducted using complementary spectroscopic techniques: Raman spectroscopy, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. In addition, density functional theory calculations were performed in order to identify specific vibrations and to monitor the product formation. The thin films of AlClPc were annealed in controlled environmental conditions to obtain (PcAl)2O. It is shown that the chemical transformation in the thin films can proceed only in the presence of water. The influence of the reaction and the annealing on the molecular orientation was studied with Raman spectroscopy and NEXAFS spectroscopy in total electron yield and partial electron yield modes. The comparison of the results obtained from these techniques allows the determination of the molecular orientation of the film as a function of the probing depth.

19.
Chem Mater ; 35(4): 1514-1526, 2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36873624

RESUMO

The syntheses of Ni-poor (NCM111, LiNi1/3Co1/3Mn1/3O2) and Ni-rich (NCM811 LiNi0.8Co0.1Mn0.1O2) lithium transition-metal oxides (space group R3̅m) from hydroxide precursors (Ni1/3Co1/3Mn1/3(OH)2, Ni0.8Co0.1Mn0.1(OH)2) are investigated using in situ synchrotron powder diffraction and near-edge X-ray absorption fine structure spectroscopy. The development of the layered structure of these two cathode materials proceeds via two utterly different reaction mechanisms. While the synthesis of NCM811 involves a rock salt-type intermediate phase, NCM111 reveals a layered structure throughout the entire synthesis. Moreover, the necessity and the impact of a preannealing step and a high-temperature holding step are discussed.

20.
J Am Chem Soc ; 134(10): 4694-9, 2012 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-22321020

RESUMO

It is demonstrated that the near-edge X-ray absorption fine structure (NEXAFS) provides a powerful local probe of functional groups in novel charge transfer (CT) compounds and their electronic properties. Microcrystals of tetra-/hexamethoxypyrene as donors with the strong acceptor tetracyano-p-quinodimethane (TMP/HMP-TCNQ) were grown by vapor diffusion. The oxygen and nitrogen K-edge spectra are spectroscopic fingerprints of the functional groups in the donor and acceptor moieties, respectively. The orbital selectivity of the NEXAFS pre-edge resonances allows us to precisely elucidate the participation of specific orbitals in the charge transfer process. Upon complex formation, the intensities of several resonances change substantially and a new resonance occurs in the oxygen K-edge spectrum. This gives evidence of a corresponding change of hybridization of specific orbitals in the functional groups of the donor (those derived from the frontier orbitals 2e and 6a(1) of the isolated methoxy group) and acceptor (orbitals b(3g), a(u), b(1g), and b(2u), all located at the cyano group) with π*-orbitals of the ring systems. Along with this intensity effect, the resonance positions associated with the oxygen K-edge (donor) and nitrogen K-edge (acceptor) shift to higher and lower photon energies in the complex, respectively. A calculation based on density functional theory qualitatively explains the experimental results. NEXAFS measurements shine light on the action of the functional groups and elucidate charge transfer on a submolecular level.

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