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1.
J Synchrotron Radiat ; 30(Pt 6): 1108-1113, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37850563

RESUMO

The spatial resolution in scanning-based two-dimensional microscopy is normally limited by the size of the probe, thereby a smaller probe is a prerequisite for enhancing the spatial resolution. For three-dimensional microscopy that combines translation and rotation motions of a specimen, however, complex trajectories of the probe highly overlap in the specimen, which could change the postulate above. Here, the spatial resolution achieved in scanning three-dimensional X-ray diffraction (s3DXRD) microscopy is investigated. In this method, the most appropriate orientation of the pixel in the specimen coordinate is selected by comparing the completeness of diffraction peaks with theory. Therefore, the superposed area of the beam trajectory has a strong effect on the spatial resolution, in terms of the completeness of diffraction peaks. It was found that the highly superposed area by the incident X-rays, which has the highest completeness factor in the pixel of the specimen, is much smaller than the X-ray probe size, and that sub-pixel analysis by dividing a pixel into small pieces leads to drastic improvement of the spatial resolution in s3DXRD.

2.
Medicina (Kaunas) ; 59(9)2023 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-37763692

RESUMO

Background: Aside from primary pseudotumor cerebri syndrome (PTCS) with an unknown etiology (i.e., idiopathic intracranial hypertension), which typically occurs in association with obesity, several conditions including cerebral venous abnormalities, drug use, and hormonal imbalance may be a secondary cause of PTCS. However, a focal space-occupying lesion outside of the brain as a cause of PTCS has rarely been reported. Case Presentation: A previously healthy 34-year-old man presented with blurred vision for three weeks. The patient had a three-month preceding history of worsening headache. On admission, he was hypertensive (160/90 mmHg) and underweight with a body mass index of 18.4 kg/m2. Fundus examination documented papilledema in both eyes. Neurological examination was unremarkable except for mild nuchal rigidity, and results of routine serologic testing were normal. Gadolinium-enhanced brain magnetic resonance imaging revealed bilateral posterior scleral flattening, suggesting intracranial hypertension. There was no other abnormal brain parenchymal lesion or meningeal enhancement. Cerebrospinal fluid (CSF) assay showed a markedly increased opening pressure (30.0 cmH2O) with normal CSF composition. A tentative diagnosis of PTCS was made based on ophthalmological, neuroradiological, and laboratory findings. During differential diagnosis, abdomen computed tomography demonstrated a huge benign cystic lesion (14.7 × 10.6 × 16.4 cm) in the right retroperitoneal space, which originated from the mesentery and resulted in hydronephrosis and renovascular hypertension due to external compression of the right kidney. Other evaluations were unremarkable. After successful surgical removal of the cyst, clinical symptoms such as headache, blurred vision, and papilledema on fundus examination were markedly improved, and blood pressure was normalized during the three-month follow-up period. Conclusions: A large retroperitoneal cyst that can increase intra-abdominal pressure could be a rare cause of PTCS. Therefore, meticulous evaluation is warranted for patients with PTCS, especially those without known risk factors.


Assuntos
Cistos , Hipertensão Intracraniana , Papiledema , Pseudotumor Cerebral , Masculino , Humanos , Adulto , Pseudotumor Cerebral/complicações , Pseudotumor Cerebral/diagnóstico , Papiledema/etiologia , Hipertensão Intracraniana/complicações , Fatores de Risco
3.
J Am Chem Soc ; 144(8): 3365-3369, 2022 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-35166532

RESUMO

The compositional space of high-entropy-alloy nanoparticles (HEA NPs) significantly expands the diversity of the materials library. Every atom in HEA NPs has a different elemental coordination environment, which requires knowledge of the local electronic structure at an atomic level. However, such structure has not been disclosed experimentally or theoretically. We synthesized HEA NPs composed of all eight noble-metal-group elements (NM-HEA) for the first time. Their electronic structure was revealed by hard X-ray photoelectron spectroscopy and density function theory calculations with NP models. The NM-HEA NPs have a lower degeneracy in energy level compared with the monometallic NPs, which is a common feature of HEA NPs. The local density of states (LDOS) of every surface atom was first revealed. Some atoms of the same constituent element in HEA NPs have different LDOS profiles, whereas atoms of other elements have similar LDOS profiles. In other words, one atom in HEA loses its elemental identity and it may be possible to create an ideal LDOS by adjusting the neighboring atoms. The tendency of the electronic structure change was shown by supervised learning. The NM-HEA NPs showed 10.8-times higher intrinsic activity for hydrogen evolution reaction than commercial Pt/C, which is one of the best catalysts.

4.
BMC Neurol ; 22(1): 294, 2022 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-35931972

RESUMO

BACKGROUND: Trigeminal neuropathy is characterized by numbness in the region innervated by the trigeminal nerves, with or without neuropathic weakness in the muscles of mastication. Trigeminal neuritis is a form of trigeminal neuropathy in which the lesion is caused by an inflammation. Herein, we report a patient with trigeminal neuritis due to central nervous system (CNS) involvement of herpes labialis (HL) infection, which was successfully treated with anti-viral and anti-inflammatory agents. CASE PRESENTATION: A young healthy female presented with numbness in the left hemiface for two weeks. She had a preceding typical HL infection on left facial lip one week before the sensory symptom onset. Brain magnetic resonance imaging revealed high signal intensities and asymmetrical thickening with enhancement along the cisternal segment of the left trigeminal nerve. Additionally, brain MR angiography showed multifocal stenoses in the M1 segment of the middle cerebral artery and the cavernous portion of the internal carotid artery. Cerebrospinal fluid (CSF) examination showed mild pleocytosis with normal protein level, glucose ratio, but CSF polymerase chain reaction assay for specific anti-viral antibodies including herpes simplex virus was negative, and CSF culture also did not identify a specific pathogen. The results of serologic testing including tumor markers and autoimmune markers were all unremarkable. A tentative diagnosis of trigeminal neuritis as a complication of HL involving the CNS was made considering the clinical, neuroradiological, and laboratory findings of the patient. Therefore, the patient was treated with intravenous methylprednisolone and acyclovir for 10 days. After the treatments, her sensory disturbance was markedly improved. Brain MRI at the 3-month follow-up also demonstrated improvement of previously identified high signal intensity lesions and multifocal intracerebral artery stenoses. CONCLUSION: HL is usually a self-limiting, benign disease without complications, but rarely presents as trigeminal neuritis due to CNS involvement. Therefore, meticulous evaluation may be necessary if trigeminal neuritis or CNS involving symptoms occur after HL.


Assuntos
Herpes Labial , Neurite (Inflamação) , Doenças do Nervo Trigêmeo , Antivirais/uso terapêutico , Encéfalo/patologia , Constrição Patológica/patologia , Feminino , Herpes Labial/tratamento farmacológico , Herpes Labial/patologia , Humanos , Hipestesia , Imageamento por Ressonância Magnética , Neurite (Inflamação)/tratamento farmacológico , Neurite (Inflamação)/etiologia , Neurite (Inflamação)/patologia , Doenças do Nervo Trigêmeo/tratamento farmacológico , Doenças do Nervo Trigêmeo/etiologia , Doenças do Nervo Trigêmeo/patologia
5.
Neurol Sci ; 43(6): 3533-3540, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35258687

RESUMO

The medial longitudinal fasciculus is a key structure for conjugate horizontal eye movements by relaying signals from the abducens internuclear neurons to the medial rectus subdivision of the contralateral oculomotor nucleus. Thus, lesions involving the medial longitudinal fasciculus give rise to a typical neuro-ophthalmological sign, the internuclear ophthalmoplegia, which is characterized by impaired adduction of the ipsilesional eye and dissociated abducting nystagmus of the contralateral eye during attempted contralesional horizontal gaze. In addition, medial longitudinal fasciculus lesions may produce various other ocular motor abnormalities since the medial longitudinal fasciculus also conveys the signals for the control of the vestibulo-ocular reflex and smooth pursuit. Other possible ocular motor abnormalities include spontaneous vertical-torsional nystagmus, contraversive ocular tilt reaction, and impaired vestibulo-ocular reflex, especially for the contralesional posterior canal. Recognition of the ocular motor findings observed in the medial longitudinal fasciculus syndrome would aid in detection and localization of potentially grave lesions involving the brainstem.


Assuntos
Nistagmo Patológico , Transtornos da Motilidade Ocular , Movimentos Oculares , Humanos , Transtornos da Motilidade Ocular/diagnóstico , Transtornos da Motilidade Ocular/etiologia , Reflexo Vestíbulo-Ocular/fisiologia , Movimentos Sacádicos , Síndrome
6.
Stroke ; 52(7): 2292-2301, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33971744

RESUMO

Background and Purpose: This study aimed to investigate the value of d-dimer levels in predicting recurrent stroke in patients with embolic stroke of undetermined source. We also evaluated the underlying causes of recurrent stroke according to d-dimer levels. Methods: A total of 1431 patients with undetermined source were enrolled in this study and divided into quartiles according to their baseline plasma d-dimer levels. The primary outcome measure was the occurrence of recurrent stroke (ischemic or hemorrhagic) in the year following the stroke event. Results: The risk of recurrent stroke increased significantly with the increasing d-dimer quartile (log-rank P=0.001). Patients in the higher d-dimer quartiles had a higher probability of recurrent embolic stroke because of covert atrial fibrillation, hidden malignancy, or undetermined sources. Most recurrent strokes in Q3 and Q4 were embolic but not in Q1 or Q2. Multivariate analysis revealed that patients in Q3 and Q4 had a significantly increased risk of recurrent stroke compared with those in Q1 (hazard ratio, 3.12 [95% CI, 1.07−9.07], P=0.036; hazard ratio, 7.29 [95% CI, 2.59−20.52], P<0.001, respectively; Ptrend<0.001). Binary analyses showed a significant association between a high d-dimer level above normal range and the risk of recurrent stroke (hazard ratio, 2.48 [95% CI, 1.31−4.70], P=0.005). In subgroup analyses, a high d-dimer level was associated with a significantly higher risk of recurrent stroke in men than in women (P=0.039). Conclusions: Our findings suggest that d-dimer levels can be a useful risk assessment biomarker for predicting recurrent stroke, especially embolic ischemic stroke, in patients with undetermined source.


Assuntos
AVC Embólico/sangue , AVC Embólico/diagnóstico por imagem , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Recidiva , Estudos Retrospectivos
7.
Neurol Sci ; 42(3): 1045-1052, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32725450

RESUMO

BACKGROUND: Isolated central positional vertigo (CPV) due to cerebellar infarction is often difficult to differentiate from benign paroxysmal positional vertigo (BPPV). Here, we aimed to evaluate whether vascular risk factors and serum vitamin D level can differentiate between positional vertigo types. METHODS: A total of 78 consecutive patients were consecutively enrolled from January 2017. All CPV patients had a National Institutes of Health Stroke Scale score of 0 and cerebellar infarctions confirmed by brain MR imaging. Vascular risk factors and serum 25-hydroxyvitamin D levels were compared between the two groups of patients. RESULTS: The proportion of men was higher in the CPV than in the BPPV group (p = 0.004). Atrial fibrillation was common in the CPV group on univariate analysis (p = 0.046). However, there were no independent differentiating factors between the two groups. The proportion of patients according to the number of risk factors was significantly different between the two groups (linear by linear association test, p = 0.02). The mean serum 25-hydroxyvitamin D level did not differ. Also, the proportions of vitamin D insufficiency and deficiency did not differ significantly between the two groups. CONCLUSIONS: Increased number of vascular risk factors including male sex suggested more CPV than BPPV. However, the serum vitamin D level was below the normal range in both groups. Our results demonstrate that serum vitamin D level has little value in the differential diagnosis of positional vertigo. Efforts to identify differentiating factors are warranted, and accumulating evidences including our research may lead to a diagnostic algorithm for isolated positional vertigo.


Assuntos
Vertigem Posicional Paroxística Benigna , Deficiência de Vitamina D , Vertigem Posicional Paroxística Benigna/complicações , Vertigem Posicional Paroxística Benigna/diagnóstico , Calcifediol , Humanos , Infarto , Masculino , Fatores de Risco
8.
Proc Natl Acad Sci U S A ; 115(22): 5703-5708, 2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29760075

RESUMO

Cresols are a group of naturally occurring and massively produced methylphenols with broad use in the chemical industry. Here, we report that m-cresol and its liquid mixtures with other isomers are surprisingly good solvents for processing carbon nanotubes. They can disperse carbon nanotubes of various types at unprecedentedly high concentrations of tens of weight percent, without the need for any dispersing agent or additive. Cresols interact with carbon nanotubes by charge transfer through the phenolic hydroxyl proton and can be removed after processing by evaporation or washing, without altering the surface of carbon nanotubes. Cresol solvents render carbon nanotubes polymer-like rheological and viscoelastic properties and processability. As the concentration of nanotubes increases, a continuous transition of four states can be observed, including dilute dispersion, thick paste, free-standing gel, and eventually a kneadable, playdough-like material. As demonstrated with a few proofs of concept, cresols make powders of agglomerated carbon nanotubes immediately usable by a broad array of material-processing techniques to create desirable structures and form factors and make their polymer composites.

9.
Stroke ; 51(12): 3514-3522, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33028171

RESUMO

BACKGROUND AND PURPOSE: We investigated the impact of the presence, burden, and location of cerebral microbleeds (CMBs) on the risk of major adverse cerebrovascular and cardiovascular events (MACCE) in patients with acute ischemic stroke and atrial fibrillation treated with oral anticoagulants (OACs). We also examined whether the clinical effect of CMBs differs according to the type of OACs. METHODS: A total of 1742 patients with acute ischemic stroke and atrial fibrillation treated with OACs were enrolled in this cohort study. The primary composite outcome was the occurrence of MACCE (a composite of stroke, acute myocardial infarction, or vascular death) over a 2-year period according to CMB status. RESULTS: CMB presence was significantly associated with the risk of future MACCE (hazard ratio, 1.89 [95% CI, 1.23-2.88]; P=0.003) after adjustment for confounders in patients with acute ischemic stroke and atrial fibrillation taking OACs. Patients with exactly 1 CMB had a similar rate of MACCE compared with those without CMBs (P=0.461). However, patients with multiple CMBs (≥2), particularly high burden CMBs (≥5), had a significantly higher proportion of MACCE. Both CMB-positive groups with lobar and deep CMB had more frequent MACCE than the CMB-negative group, and the rate of MACCE was not different according to CMB location. In patients treated with warfarin, CMB was significantly associated with a risk of MACCE (P=0.002), but not in patients treated with direct OACs (P=0.517). CONCLUSIONS: The study results indicate that the risk of future MACCE increased with increasing CMB burden in patients with AIS and atrial fibrillation taking OACs, while the anatomic location of CMBs did not influence the risk of future MACCE. This risk seemed to be more apparent in patients taking warfarin.


Assuntos
Anticoagulantes/uso terapêutico , Fibrilação Atrial/tratamento farmacológico , Hemorragia Cerebral/epidemiologia , AVC Embólico/tratamento farmacológico , Acidente Vascular Cerebral Hemorrágico/epidemiologia , Infarto do Miocárdio/epidemiologia , Doenças Vasculares/mortalidade , Idoso , Idoso de 80 Anos ou mais , Fibrilação Atrial/complicações , Hemorragia Cerebral/diagnóstico por imagem , AVC Embólico/epidemiologia , AVC Embólico/etiologia , Feminino , Humanos , AVC Isquêmico/tratamento farmacológico , AVC Isquêmico/epidemiologia , AVC Isquêmico/etiologia , Masculino , Pessoa de Meia-Idade , Recidiva
10.
BMC Cancer ; 20(1): 1206, 2020 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-33287745

RESUMO

BACKGROUND: We aimed to identify whether neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are more useful predictors after initial intention to treat than at the time of diagnosis. METHODS: We collected the medical data of 533 patients. The results of the peripheral blood sampling before the primary treatments were labeled as initial cohort, and those obtained between 24 and 36 months after initial treatment were defined as the 2nd cohort. Delayed metastasis has been defined as distant metastasis 2 years after treatment, and survival outcome was estimated and compared across groups. RESULTS: Median follow-up duration was 74 months (24-162 months), and 53 patients experienced delayed metastasis. In univariate analysis, metastasis-free survival, patient age at diagnosis, tumor size, axillary lymph node metastasis, HER-2 status, initial NLR and PLR, and 2nd NLR and PLR were found to be significantly associated with delayed metastasis. However, in multivariate analysis, only the 2nd NLR and PLR were found to be significantly associated with delayed metastasis, excluding initial NLR and PLR. Metastasis-free survival was analyzed through the pattern changes of NLR or PLR. The results revealed that patients with continued low NLR and PLR values at pre- and post-treatment (low initial values and 2nd values) showed a significantly better prognosis than those with a change in value or continued high NLR and PLR. CONCLUSIONS: We identified that patients with persistent high NLR and PLR after initial treatment have significant worse prognosis in terms of late metastasis. Therefore, these results suggest that NLR and PLR are more useful in predicting prognosis post-treatment.


Assuntos
Plaquetas/metabolismo , Neoplasias da Mama/sangue , Linfócitos/metabolismo , Neutrófilos/metabolismo , Neoplasias da Mama/mortalidade , Feminino , Humanos , Pessoa de Meia-Idade , Análise de Sobrevida
12.
World J Surg Oncol ; 17(1): 8, 2019 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-30616645

RESUMO

BACKGROUND: While extended cholecystectomy is recommended for T2 gallbladder cancer (GBC), the role of hepatic resection for T2 GBC is unclear. This study aimed to identify the necessity of hepatic resection in patients with T2 GBC. METHODS: Data of 81 patients with histopathologically proven T2 GBC who underwent surgical resection between January 1999 and December 2017 were enrolled from a retrospective database. Of these, 36 patients had peritoneal-side (T2a) tumors and 45 had hepatic-side (T2b) tumors. To identify the optimal surgical management method, T2 GBC patients were classified into the hepatic resection group (n = 44, T2a/T2b = 20/24) and non-hepatic resection group (n = 37, T2a/T2b = 16/21). The recurrence pattern and role of hepatic resection for T2 GBC were then investigated. RESULTS: Mean age of the patients was 69 (range 36-88) years, and the male-to-female ratio was 42:39 (male, 51.9%; female, 48.1%). Hepatic-side GBC had a higher rate of recurrence than peritoneal-side GBC (44.4% vs. 8.3%, p = 0.006). The most common type of recurrence in T2a GBC was para-aortic lymph node recurrence (n = 2, 5.6%); the most common types of recurrence in T2b GBC were para-aortic lymph node recurrence (n = 7, 15.6%) and intrahepatic metastasis (n = 6, 13.3%). Hepatic-side GBC patients had worse survival outcomes than peritoneal-side GBC patients (76.0% vs. 96.6%, p = 0.041). Hepatic resection had no significant treatment effect in T2 GBC patients (p = 0.272). Multivariate analysis showed that lymph node metastasis was the only significant prognostic factor (p = 0.002). CONCLUSIONS: Hepatic resection is not essential for curative treatment in T2 GBC, and more systemic treatments are needed for GBC patients, particularly for those with T2b GBC.


Assuntos
Adenocarcinoma/cirurgia , Colecistectomia/mortalidade , Neoplasias da Vesícula Biliar/cirurgia , Hepatectomia/mortalidade , Recidiva Local de Neoplasia/cirurgia , Adenocarcinoma/secundário , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Neoplasias da Vesícula Biliar/patologia , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/patologia , Prognóstico , Estudos Retrospectivos , Taxa de Sobrevida
13.
J Am Chem Soc ; 137(5): 1742-5, 2015 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-25608577

RESUMO

Lithiation-exfoliation produces single to few-layered MoS2 and WS2 sheets dispersible in water. However, the process transforms them from the pristine semiconducting 2H phase to a distorted metallic phase. Recovery of the semiconducting properties typically involves heating of the chemically exfoliated sheets at elevated temperatures. Therefore, it has been largely limited to sheets deposited on solid substrates. Here, we report the dispersion of chemically exfoliated MoS2 sheets in high boiling point organic solvents enabled by surface functionalization and the controllable recovery of their semiconducting properties directly in solution. This process connects the scalability of chemical exfoliation with the simplicity of solution processing, ultimately enabling a facile method for tuning the metal to semiconductor transitions of MoS2 and WS2 within a liquid medium.


Assuntos
Dissulfetos/química , Molibdênio/química , Semicondutores , Compostos de Tungstênio/química , Modelos Moleculares , Conformação Molecular , Soluções , Solventes/química , Propriedades de Superfície
14.
Int J Syst Evol Microbiol ; 65(7): 2277-2285, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25870258

RESUMO

From the whole blood of Korean native cattle, Hanwoo (Bos taurus coreanae), a previously undescribed, rapidly growing, scotochromogenic isolate of the genus Mycobacterium is reported. Its 16S rRNA gene sequence, and the sequences of three other genes (hsp65, recA and rpoB) were unique and phylogenetic analysis based on 16S rRNA gene sequence (1420 bp) placed the organism into the rapidly growing Mycobacterium group close to Mycobacterium smegmatis (98.5% sequence similarity). However, phylogenetic analyses based on three different gene sequences (hsp65, recA and rpoB) revealed its location to be distinct from the branch of rapidly growing species. Culture and biochemical characteristics were generally similar to those of Mycobacterium fortuitum. Unique matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS profiles of lipids, unique fatty acid profile, unique mycolic acids profiles and a low DNA-DNA relatedness to M. fortuitum (23.6%) and M. smegmatis (39.7%) strongly supported the taxonomic status of this strain as a representative of a novel species of rapidly growing mycobacteria named Mycobacterium anyangense. The type strain is strain QIA-38(T) ( = JCM 30275(T) = KCTC 29443(T)).


Assuntos
Doenças dos Bovinos/microbiologia , Bovinos/microbiologia , Infecções por Mycobacterium/veterinária , Micobactérias não Tuberculosas/classificação , Filogenia , Animais , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Genes Bacterianos , Dados de Sequência Molecular , Infecções por Mycobacterium/microbiologia , Ácidos Micólicos/química , Micobactérias não Tuberculosas/genética , Micobactérias não Tuberculosas/isolamento & purificação , Hibridização de Ácido Nucleico , Peptidoglicano/química , Pigmentação , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA
19.
Nano Lett ; 14(5): 2946-51, 2014 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-24773449

RESUMO

We employ mixed self-assembled monolayers of carboranethiols to alter the work function of gold and silver systematically. We use isomers of symmetric carboranethiol cage molecules to vary molecular dipole moments and directions, which enable work function tunability over a wide range with minimal alterations in surface energy. Mixed monolayers of carboranethiol isomers provide an ideal platform for the study and fabrication of solution-processed organic field-effect transistors; improved device performance is demonstrated by interface engineering.

20.
Acc Chem Res ; 46(10): 2225-34, 2013 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-23425088

RESUMO

Graphene-based sheets show promise for a variety of potential applications, and researchers in many scientific disciplines are interested in these materials. Although researchers have developed many ways of generating single atomic layer carbon sheets, chemical exfoliation of graphite powders to graphene oxide (GO) sheets followed by deoxygenation to form chemically modified graphene (CMG) offers a promising route for bulk scale production. The materials processing, which we broadly define as the physical and chemical means to tailor a material's chemical and microstructures, enables us to control the properties in bulk CMG materials. For example, by processing CMG sheets in different solvents, we can make thin films, blend CMG sheets with other materials, and modify them by chemical reactions. Materials processing methods also allow us to control the interactions between CMG sheets for the assembly of large scale two- or three-dimensional structures with desirable microstructures. This Account highlights a few problems associated with large scale production and processing of GO and CMG. First, we briefly discuss the potential fire risk of GO and CMG when alkaline salt byproducts are not completely removed. These impurities can catalyze carbon combustion. We introduce an improved purification procedure that effectively removes the byproducts and speeds up the production. Next, we address the challenges of imaging GO and CMG sheets on common substrates such as glass and plastics using standard microscopy methods. We have introduced a new technique fluorescence quenching microscopy (FQM), which allows us to observe graphene-based sheets with both high throughput and high contrast on arbitrary substrates and even in solution. Then we focus on how to prevent aggregation in CMG. Aggregation greatly reduces the material processability and accessible surface area, which degrades the material properties. We introduce two strategies to reduce aggregation by (i) reducing the lateral dimension of the sheets to nanometer range to enhance their colloidal stability and (ii) crumpling the sheets into paper ball-like, fractal-dimensional particles to make them aggregation-resistant in both solvents and solid state, even after mechanical compression. Solutions to these material processing challenges can pave the way for further research and development. We hope that the tools and strategies presented in this Account can facilitate the processing and property control of this promising material.

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