Retrospective Comparative Analysis of Clinical and Functional Outcome After Arthroscopic Bankart Repair using All-Suture Anchor and Metal Anchor

Introduction

Both knotted all suture anchors and metal anchors are used for arthroscopic Bankart repair. We retrospectively evaluated and compared clinical and functional outcomes after arthroscopic Bankart repair using the knotted all-suture anchors and knotted metal anchors.

Materials and methods

In a retrospective cohort analysis, patients who underwent arthroscopic Bankart repair without any concomitant additional lesion repair using either all-suture anchors or metal anchors, between January 2015 and May 2018 were identified. Their pre- and post-operative functional and clinical outcomes were compared using Rowe and WOSI scores. The recurrence rate in the two groups was also compared.

Results

A total of 41 patients in all suture anchors group and 47 in the metal anchors group were identified as per inclusion and exclusion criteria. The demographic profile of both groups was comparable. There was no significant difference in clinical and functional outcome between the two suture anchor groups as per Rowe (pre-operative 40.13+6.51 vs 38.09+6.24 and post-operative 2 years 93.28+7.09 vs 92.55+9.2) and WOSI (pre-operative 943.05+216.64 vs 977.55+165.46 and post-operative 2 years 278.21+227.56 vs 270.94+186.25) scores. There was a significant improvement in both the groups between preoperative and post-operative ROWE and WOSI scores at 6 months and 2 years follow-up as compared to pre-operative scores (p<0.001). Re-dislocation rates were also comparable (4.8% vs 6.3%).

Conclusion

All-suture anchors showed comparable clinical and functional results as the metal anchors for arthroscopic Bankart repair at two-year follow-up.

Computational insight towards the binding affinity and participation of aliphatic unsaturated sidearms of aza-18-crown-6 extractants for Sr2+ encapsulation in different solvent medium

CONTEXT

Macrocyclic extractants capture cations in solution phase; therefore, their structures and energetics in different solvents are worth investigating. In this computational research work, the optimized geometry of three aza-18-crown-6 extractants (1-3) has been obtained in suitable solvent mediums to work out the influence of the solvation on their binding affinity with Sr2+. The designed macrocyclic extractants are remarkable as the N-substituted side chain bears the rarely examined simple aliphatic unsaturated double and triple bond. All significant structural perturbations of the macro ring wherein Sr2+ binds are examined. Prediction of the auxiliary effect of the simple aliphatic unsaturated side arm on the binding of Sr2+ through solvent competition or cation-pi interaction is undertaken. The binding affinity of the complex formed in the solvent and gas phases is calculated. Results obtained in this study favor the utilization of solvents of low dielectric constant (CHCl3 and DCM) for effective binding of Sr2+ ions by the extractants.

METHOD

All DFT calculations were performed using the Gaussian 09 program. The optimized geometries and their structural features were visualized by GaussView. Density functional calculation involving B3LYP functional and LANL2DZ basis set was employed to obtain optimized geometry and energy of the extractants and their Sr2+ complex. The solvation effects were considered by employing the calculations with the polarized continuum model (PCM). The computational method's reliability was assured by comparing the optimized structure with that of X-ray reported structure of a similar type of complex.

Dissecting the clinicopathologic, genomic, and immunophenotypic correlates of KRASG12D-mutated non-small-cell lung cancer

BACKGROUND

Allele-specific KRAS inhibitors are an emerging class of cancer therapies. KRAS-mutant (KRASMUT) non-small-cell lung cancers (NSCLCs) exhibit heterogeneous outcomes, driven by differences in underlying biology shaped by co-mutations. In contrast to KRASG12C NSCLC, KRASG12D NSCLC is associated with low/never-smoking status and is largely uncharacterized.

PATIENTS AND METHODS

Clinicopathologic and genomic information were collected from patients with NSCLCs harboring a KRAS mutation at the Dana-Farber Cancer Institute (DFCI), Memorial Sloan Kettering Cancer Center, MD Anderson Cancer Center, and Imperial College of London. Multiplexed immunofluorescence for CK7, programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), Foxp3, and CD8 was carried out on a subset of samples with available tissue at the DFCI. Clinical outcomes to PD-(L)1 inhibition ± chemotherapy were analyzed according to KRAS mutation subtype.

RESULTS

Of 2327 patients with KRAS-mutated (KRASMUT) NSCLC, 15% (n = 354) harbored KRASG12D. Compared to KRASnon-G12D NSCLC, KRASG12D NSCLC had a lower pack-year (py) smoking history (median 22.5 py versus 30.0 py, P < 0.0001) and was enriched in never smokers (22% versus 5%, P < 0.0001). KRASG12D had lower PD-L1 tumor proportion score (TPS) (median 1% versus 5%, P < 0.01) and lower tumor mutation burden (TMB) compared to KRASnon-G12D (median 8.4 versus 9.9 mt/Mb, P < 0.0001). Of the samples which underwent multiplexed immunofluorescence, KRASG12D had lower intratumoral and total CD8+PD1+ T cells (P < 0.05). Among 850 patients with advanced KRASMUT NSCLC who received PD-(L)1-based therapies, KRASG12D was associated with a worse objective response rate (ORR) (15.8% versus 28.4%, P = 0.03), progression-free survival (PFS) [hazard ratio (HR) 1.51, 95% confidence interval (CI) 1.45-2.00, P = 0.003], and overall survival (OS; HR 1.45, 1.05-1.99, P = 0.02) to PD-(L)1 inhibition alone but not to chemo-immunotherapy combinations [ORR 30.6% versus 35.7%, P = 0.51; PFS HR 1.28 (95%CI 0.92-1.77), P = 0.13; OS HR 1.36 (95%CI 0.95-1.96), P = 0.09] compared to KRASnon-G12D.

CONCLUSIONS

KRASG12D lung cancers harbor distinct clinical, genomic, and immunologic features compared to other KRAS-mutated lung cancers and worse outcomes to PD-(L)1 blockade. Drug development for KRASG12D lung cancers will have to take these differences into account.

The development of a robust folded scaffold as a fluorescent material using butylidine-linked pyridazinone-based systems via aromatic π⋯π stacking interactions

Fluorescence-capable robust folded pyridazinone-based homo- and heterodimers linked with butylidine linkers, whose crystals exhibit fluorescence with quantum yields of 11% (1CN) and 28% (2CN) due to intramolecular stacking, were synthesized.

Iyengar-Botchu (IB) confluence of the medial knee- anatomy and clinico-radiological review

The Iyengar-Botchu confluence is a quadrilateral space on the medial side of the knee. Due to the presence of unique anatomical structures, this region is prone to injuries. The aim of this pictorial review is to illustrate an anatomical description of the structures, which form the IB complex confluence. Clinico-pathological correlation of common conditions associated with these structures will increase awareness of injuries in this area. A complementary imaging guidance will support clinical diagnosis and appropriate patient management.

Activation of TRPV4 by mechanical, osmotic or pharmaceutical stimulation is anti-inflammatory blocking IL-1β mediated articular cartilage matrix destruction

OBJECTIVE

Cartilage health is maintained in response to a range of mechanical stimuli including compressive, shear and tensile strains and associated alterations in osmolality. The osmotic-sensitive ion channel Transient Receptor Potential Vanilloid 4 (TRPV4) is required for mechanotransduction. Mechanical stimuli inhibit interleukin-1β (IL-1β) mediated inflammatory signalling, however the mechanism is unclear. This study aims to clarify the role of TRPV4 in this response.

DESIGN

TRPV4 activity was modulated glycogen synthase kinase (GSK205 antagonist or GSK1016790 A (GSK101) agonist) in articular chondrocytes and cartilage explants in the presence or absence of IL-1β, mechanical (10% cyclic tensile strain (CTS), 0.33 Hz, 24hrs) or osmotic loading (200mOsm, 24hrs). Nitric oxide (NO), prostaglandin E₂ (PGE₂) and sulphated glycosaminoglycan (sGAG) release and cartilage biomechanics were analysed. Alterations in post-translational tubulin modifications and primary cilia length regulation were examined.

RESULTS

In isolated chondrocytes, mechanical loading inhibited IL-1β mediated NO and PGE₂ release. This response was inhibited by GSK205. Similarly, osmotic loading was anti-inflammatory in cells and explants, this response was abrogated by TRPV4 inhibition. In explants, GSK101 inhibited IL-1β mediated NO release and prevented cartilage degradation and loss of mechanical properties. Upon activation, TRPV4 cilia localisation was increased resulting in histone deacetylase 6 (HDAC6)-dependent modulation of soluble tubulin and altered cilia length regulation.

CONCLUSION

Mechanical, osmotic or pharmaceutical activation of TRPV4 regulates HDAC6-dependent modulation of ciliary tubulin and is anti-inflammatory. This study reveals for the first time, the potential of TRPV4 manipulation as a novel therapeutic mechanism to supress pro-inflammatory signalling and cartilage degradation.

Power Doppler in musculoskeletal ultrasound: uses, pitfalls and principles to overcome its shortcomings

Power Doppler (PD) is used widely in musculoskeletal ultrasound, especially in the assessment of structures for evidence of inflammation and in evaluating soft tissue neoplasms. We reinforce and delineate the three cardinal principles of optimising PD assessment in order to avoid false positive or false negative results; namely (1) Optimal gain settings (2) Adequate transducer pressure, and (3) Proper patient/anatomical structure-of-interest positioning with complete tissue relaxation.

Anatomy and pathology of facet joint

Facet joints are the only synovial joints in the spine and can be involved in a large number of pathological processes including arthropathy, infection, inflammation, trauma and tumour. In this review article, we present a spectrum of pathologies that arise from or involve facet joints that we have encountered in our tertiary orthopaedic and spinal centre. The objective of this review is to create an aide memoire for the general radiologist who may encounter facet joint pathology, which they may not be familiar with.

A Comparison of the Reliability of the Patellar Tendon-Trochlear Groove (PTTG) Distance and the Tibial Tuberosity-Trochlear Groove (TTTG) Distance Measured on MRI

Introduction:

An increased tibial tuberosity-trochlear groove (TTTG) distance is used for deciding a treatment plan in patello-femoral instability (PFI). The centre of the patellar tendon and the chondral trochlear groove can be directly visualised on MRI, and measured, giving the patellar tendon-trochlear groove (PTTG) distance. A study was designed to compare the inter-rater and the test-retest reliabilities of PTTG and TTTG measurements in MRI of patients without PFI and in a group with PFI.

Materials and Methods:

This cross-sectional reliability study was done on archival MRI films of 50 patients without patellar instability and 20 patients with patellar instability. TTTG and PTTG distances were independently measured by two orthopaedic surgeons and two radiologists. A hybrid PTTG measurement with bony landmarks on the femoral side and the patellar tendon landmark on the tibial side, was used to estimate the influence of the differences in the femoral and tibial landmarks on the difference in reliabilities. The intra-class correlation coefficient (ICC) was calculated for all four raters, as well as separately for each rater.

Results:

The PTTG distance had a higher inter-rater reliability (ICC=0.86, 95% CI=0.79-0.92) compared to the TTTG distance (ICC=0.70, 95% CI=0.59-0.80) in patients without PFI. Similar trends were seen in patients with PFI (0.83 vs 0.66). The inter-rater reliability for the hybrid PTTG distance was found to lie in between the TTTG and PTTG.

Conclusions:

The MRI-based PTTG distance had better inter-rater reliability compared with the MRI-based TTTG distance.

Single-Step Synthesis of Magnesium-Doped Lithium Manganese Oxide Nanosorbent and Their Polymer Composite Beads for Selective Heavy Metal Removal

Magnesium-doped lithium manganese oxide nanosorbent is prepared by a single-step solid-state method and characterized with appropriate analytical techniques, adsorption kinetic model, and isotherms. Competitive and noncompetitive adsorption studies are performed for a range of heavy metal ions. Prepared nanosorbent has shown explicit selectivity for various heavy metal ions and no remarkable influence of coexisting common interfering ions (Na⁺, K⁺, Mg²⁺, and Ca²⁺), which generally coexist with all natural sources of water, contaminated water, and industrial waste. To achieve easy handling of an adsorbent, polysulfone-nanosorbent (PS-nanosorbent) composite beads are prepared, and their competitive heavy metal removal performance is determined. Competitive adsorption and regeneration studies have shown that PS-nanosorbent beads can be employed for selective heavy metal removal and reuse for multiple cycles.

An Eye Opener: Lessons Learnt in Retinoblastoma Awareness and Screening Program

Background: Retinoblastoma is most common intraocular malignancy of infancy. Globally screening is recommended for ‘at risk’ children. Despite knowing this, Indian Cancer Society undertook general screening at behest of a corporate donor. Scenario in India is challenging as children at rural, urban slums are not routinely screened for any of eye disease. ICS implemented the pilot project among underprivileged children with primary aim of spreading awareness and improve the ocular health. Though expected outcome was zero retinoblastoma suspect cases; based on past projects it was expected that other eye conditions like squint, cataract etc. would be identified in a few. Aim: To screen 4500 children below 4 years of age at Indian rural and suburban slum areas. To create awareness about retinoblastoma and other eye conditions in community. Methods: Locations were identified where literacy, awareness, immunization coverage were low. Partners were selected a team of experts (ocular oncologists, pediatric ophthalmologists, optometrists, paramedical staff) were deployed for implementation. For awareness, all parents coming for the immunization, Aaganwadis and preschools etc. were given a talk on the importance of child eye screening and various disease which can be detected and prevented through simple eye examination. Special community level programs planned to create awareness about retinoblastoma and early childhood eye screening. Brochures and pamphlets were to be given in the vernacular language of the region. Screening for retinoblastoma was planned in 2 phases, those found to have positive red reflex in stage 1 are subjected to dilation, after obtaining consent from the parents. Proformas were filled in and treatment was given as per the pediatric eye disease identified. Results: In 5 months 2450 children were screened, at tribal area and in suburban slum areas. Awareness sessions were conducted for 348 mothers in batches at the tribal area and similarly for mothers and teachers at Anganwadi, schools. None of the parents/teachers were aware about cancer of eye. A thorough eye check-up was done based on the suggestions of the American Association of Pediatric eye diseases and special attention was given to tests such as Bruckners test. Number of children suspected of retinoblastoma was nil, however, 6% children were found to have other eye conditions such as congenital cataract, corneal opacity, refractive errors, squints and ptosis in the tribal area and project is ongoing in suburban area. Treatment was given as per the protocol for same. Conclusion: Screening for retinoblastoma for not at risk children is not recommended. Main aim for implementing retinoblastoma awareness program is to integrate it with immunization or nutritional program in India. This would ensure standardized ocular care. Challenges are numerous, such as lack of infrastructure, poor literacy rates, low income levels. Yet, innovative strategies are needed for better impact of awareness programs.

An Information Theory Approach to Identifying a Representative Subset of Hydro-Climatic Simulations for Impact Modeling Studies

Uncertainties in hydro-climatic projections are (in part) related to various components of the production chain. An ensemble of numerous projections is usually considered to characterize the overall uncertainty; however in practice a small set of scenario combinations are constructed to provide users with a subset that is manageable for decision-making. Since projections are unavoidably uncertain, and multiple projections are typically informationally redundant to a considerable extent, it would be helpful to identify an informationally representative subset in a large model ensemble. Here a framework rooted in the information theoretic Maximum Information Minimum Redundancy concept is proposed for identifying a representative subset from an available ensemble of hydro-climatic projections. We analyze an ensemble of 16 precipitation and temperature projections for Sweden, and use these as inputs to the HBV hydrological model to project river discharge until the mid of this century. Representative subsets are judged in terms of different statistical properties of three essential climate variables (precipitation, temperature and discharge), whilst we further assess the sensitivity of the optimized subset for different seasons and future periods. Our results indicate that a quarter to a third of the available set of projections can represent more than 80% of the total information of hydro-climatic changes. We find that the representative subsets are sensitive to the regional hydro-climatic characteristics and the choice of variables, seasons and periods of interest. Therefore we recommend that any selection process should not be solely driven by climatic variables but, rather, should also consider variables of the impact model.

Enhanced Electrochemical Performance of Stable SPES/SPANI Composite Polymer Electrolyte Membranes by Enriched Ionic Nanochannels

Herein, we present the results of sulfonated polyaniline (SPANI) and sulfonated poly(ether sulfone) (SPES) composite polymer electrolyte membranes. The membranes are established for high-temperature proton conductivity and methanol permeability to render their applicability. Composite membranes have been prepared by modifying the SPES matrix with different concentrations of SPANI (e.g., 1, 2, 5, 10, and 20 wt %). Structural and thermomechanical characterizations have been performed using the transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analyzer techniques. Physicochemical and electrochemical properties have been evaluated by water uptake, ion-exchange capacity, dimensional stability, and proton conductivity. Methanol permeability experiment was carried out to analyze the compatibility of prepared membranes toward direct methanol fuel cell application and found the lowest methanol permeability for PAS-5. Also, the membranes reveal excellent thermal, mechanical, and physicochemical properties for their application toward high-temperature electromembrane processes.

Role of online technology and social networking site at workplace

Background

Internet use has affected the pattern of working style at the workplace. Recent years have seen an increased use of online activities (especially pornography/gaming) at the workplace. It has been shown to affect productivity at the workplace. There is a dearth of literature from the Indian context in this area.

Aim

This study was conducted to explore the pattern of pornography use& gaming at the workplace and its dysfunctions. Setting and design: The present study was a cross-sectional prospective study

Materials and methods

The objective of the study was to assess the pattern of pornography use at the workplace. Five hundred employees having experience of Internet use for more than a year of various government/private sector organizations in Bengaluru were assessed using background data sheet, DSM V criteria, Internet addiction test & pornography addiction screening instrument. Users who were unwilling to participate were excluded from the study.

Results

Seven to nine percent reported preference for Internet to work, meals, personal hygiene, sleep, and interaction with family members and effects on productivity. Three to four percent have excessive use of pornography & game.

Conclusions

The present study has implications for evolving psychoeducational modules for the promotion of healthy use of technology.

Disclosure of interest

The author has not supplied his/her declaration of competing interest.

Pattern of online technology and its impact on productivity at workplace

Background

Internet use has affected the pattern of working style at the workplace. Recent years have seen an increased use of online activities (especially pornography/gaming) at the workplace. It has been shown to affect productivity at the workplace. There is a dearth of literature from the Indian context in this area.

Aim

This study was conducted to explore the pattern of pornography use and gaming at the workplace and its dysfunctions.

Setting and design

The present study was a cross-sectional prospective study.

Materials and methods

The objective of the study was to assess the pattern of pornography use at the workplace. Five hundred employees having experience of internet use for more than a year of various government/private sector organizations in Bengaluru were assessed using background data sheet, DSM-5 criteria, internet addiction test and pornography addiction screening instrument. Users who were unwilling to participate were excluded from the study.

Results

Seven to 9% reported preference for Internet to work, meals, personal hygiene, sleep, and interaction with family members and effects on productivity. Three to 4% have excessive use of pornography and game.

Conclusions

The present study has implications for evolving psychoeducational modules for the promotion of healthy use of technology.

Disclosure of interest

The author has not supplied his declaration of competing interest.

Do quantitative and qualitative shear wave elastography have a role in evaluating musculoskeletal soft tissue masses?

Objectives

To determine if quantitative and qualitative shear wave elastography have roles in evaluating musculoskeletal masses.

Methods

105 consecutive patients, prospectively referred for biopsy within a specialist sarcoma centre, underwent B-mode, quantitative (m/s) and qualitative (colour map) shear wave elastography. Reference was histology from subsequent biopsy or excision where possible. Statistical modelling was performed to test elastography data and/or B-mode imaging in predicting malignancy.

Results

Of 105 masses, 39 were malignant and 6 had no histology but benign characteristics at 12 months. Radiologist agreement for B-mode and elastography was moderate to excellent Kw 0.52-0.64; PABAKw 0.85-0.90). B-Mode imaging had 78.8% specificity, 76.9% sensitivity for malignancy. Quantitatively, adjusting for age, B-mode and lesion volume there was no statistically significant association between longitudinal velocity and malignancy (OR [95% CI] 0.40[0.10, 1.60], p=0.193), but some evidence that higher transverse velocity was associated with decreased odds of malignancy (0.28[0.06, 1.28], p=0.101). Qualitatively malignant masses tended to be towards the blue spectrum (lower velocities); 39.5% (17/43) of predominantly blue masses were malignant, compared to 14.3% (1/7) of red lesions.

Conclusions

Quantitatively and qualitatively there is no statistically significant association between shear wave velocity and malignancy. There is no clear additional role to B-mode imaging currently.

Key Points

• Correlation between shear wave velocity and soft tissue malignancy was statistically insignificant

• B-mode ultrasound is 76.9 % sensitive and 78.8 % specific

• Statistical models show elastography does not significantly add to lesion assessment

Single step synthesis of a magnesium doped lithium manganese oxide ion sieve nanomaterial and a SPES/ion sieve composite membrane for the separation of lithium

Magnesium doped lithium manganese oxide nanostructured ion sieve materials are prepared through a single step solid state reaction and characterized with appropriate analytical techniques.

An environmentally friendly process for the synthesis of an fGO modified anion exchange membrane for electro-membrane applications

We report the synthesis of an anion exchange membrane (AEM) based on chemically covalently modified graphene oxide (GO) for electrodialysis and fuel cell applications.

Face-to-face stacking in sulfonamide based bis-ethylene bridged heteroaromatic dimers

Four sulfonamide based bis-ethylene bridged heteroaromatic dimers were crystallized in offset face-to-face stacked geometry. Further, density functional theory revealed that crystallized structures were the most stable conformers.

Stabilization of microtubules by taxane diterpenoids: insight from docking and MD simulations

Microtubules are formed from the molecules of tubulin, whose dynamics is important for many functions in a cell, the most dramatic of which is mitosis. Taxol is known to interact within a specific site on tubulin and also believed to block cell-cycle progression during mitosis by binding to and stabilizing microtubules. Along with the tremendous potential that taxol has shown as an anticancer drug, clinical problems exist with solubility, toxicity, and development of drug resistance. The crystal structure of taxane diterpenoids, namely, 10, 13-deacetyl-abeo-baccatin-IV (I), 5-acetyl-2-deacetoxydecinnamoyl-taxinine-0.29hydrate (II), 7, 9-dideacetyltaxayuntin (III), and Taxawallin-K (IV), are very similar to the taxol molecule. Considerable attention has been given to such molecules whose archetype is taxol but do not posses long aliphatic chains, to be developed as a substitute for taxol with fewer side effects. In the present work, the molecular docking of these taxane diterpenoids has been carried out with the tubulin alpha-beta dimer (1TUB) and refined microtubule structure (1JFF) using Glide-XP, in order to assess the potential of tubulin binding of these cytotoxic agents. Results show that all the ligands dock into the classical taxol binding site of tubulin. Taxol shows the best binding capabilities. On the basis of docking energy and interactions, apart from taxol, molecule II has a better tendency of binding with 1TUB while molecule I shows better binding capability with bovine tubulin 1JFF. To validate the binding capabilities, molecular dynamics (MD) simulations of the best docked complexes of ligands with 1JFF have been carried out for 15.0 ns using DESMOND. Average RMSD variations and time line study of interactions and contacts indicate that these complexes remain stable during the course of the dynamics. However, taxol and molecule II prevail over other taxoids.

Temperature-dependent solubility transition of Na₂SO₄ in water and the effect of NaCl therein: solution structures and salt water dynamics

Dual, aqueous solubility behavior of Na2SO4 as a function of temperatures is still a natural enigma lying unresolved in the literature. The solubility of Na2SO4 increases up to 32.38 °C and decreases slightly thereafter at higher temperatures. We have thrown light on this phenomenon by analyzing the Na2SO4-water clusters (growth and stability) detected from temperature-dependent dynamic light scattering experiments, solution compressibility changes derived from the density and speed of sound measurements, and water structural changes/Na2SO4 (ion pair)-water interactions observed from the FT-IR and 2D DOSY (1)H NMR spectroscopic investigations. It has been observed that Na2SO4-water clusters grow with an increase in Na2SO4 concentration (until the solubility transition temperature) and then start decreasing afterward. An unusual decrease in cluster size and solution compressibility has been observed with the rise in temperature for the Na2SO4 saturated solutions below the solubility transition temperature, whereas an inverse pattern is followed thereafter. DOSY experiments have indicated different types of water cluster species in saturated solutions at different temperatures with varying self-diffusion coefficients. The effect of NaCl (5-15 wt %) on the solubility behavior of Na2SO4 at different temperatures has also been examined. The studies are important from both fundamental and industrial application points of view, for example, toward the clean separation of NaCl and Na2SO4 from the effluent streams of textile and tannery industries.

Preparation of graphene oxide nano-composite ion-exchange membranes for desalination application

Different membrane properties by inclusion of graphene oxide content.