This atomic rearrangement underthe graphene layer results in aperiodic patterning of the two-dimensional(2D) material. The electronic structure of the resulting nanostructuredgraphene is dominated by a linear dispersion of the Dirac quasiparticles,characteristic of its free-standing state but with a p-doping character. The local effects of the underlying missing rowson the interfacial chemistry and on the quasiparticle scattering processesin graphene are studied using atomically resolved STM images. Thepossibilities offered by this nanostructuring approach, which consistsin inducing surface reconstructions under graphene, could providea novel tuning strategy for this 2D material.Artificial nanostructuringof graphene has served as a platformto induce variations in its structural and electronic properties,fostering the experimental observation of a wide and fascinating phenomenology.Here, we present an approach to graphene tuning, based on Rh(110)surface reconstruction induced by oxygen atoms intercalation. Theresulting nanostructured graphene has been characterized by scanningtunneling microscopy (STM) complemented by low-energy electron microscopy(LEEM), micro low-energy electron diffraction (μ-LEED), microangle-resolved photoemission spectroscopy (μ-ARPES), and microX-ray photoelectron spectroscopy (μ-XPS) measurements underultrahigh vacuum (UHV) conditions at room temperature (RT). It isfound that by fine-tuning the O Initially,the work focused on pristine graphene layers, where phenomena suchas the massless quasiparticle behavior,6 resulting in a linear band structure, or quantum hall effect,8 have been observed. Interestingly, the two-dimensional nature ofthis material makes it more sensitive to the presence of defects,as well as to other elements placed in the local environment. Thisfact has opened up new research opportunities, providing a platformfor the controlled tuning of graphene properties to pursue the explorationof novel phenomena.Morethan 15 years after the first isolation of graphene,9 or graphene bubbles10 has beenshown to induce an interesting phenomenology. While for the former,the existence of localized states, characterized by a certain magneticmoment,9 has been reported, for the latter,the existence of giant pseudomagnetic fields has been established.10 From the point of view offered by the possibilityof tuning the properties of graphene by interacting with other elements,the deposition of atoms,11 molecules,12 and clusters13 ontop of graphene has been shown to induce, for example, magnetism,11 doping,12 bandgapopening,13 or asymmetries in the groupvelocities of quasiparticles13 among others.Accordingly, the choice of support has also provided a versatile toolto modify the properties of graphene. These effects range from onlyslight changes in the electronic properties, such as doping14 or the opening of minigaps15 and the formation of band replicas,15 due to the potential felt by the quasiparticles, associatedwith the superstructures resulting from the lattice mismatch betweengraphene and the support, known as moiré patterns, to the completeabsence of Dirac cones near the Fermi level.17 Both the metal element forming the support and the symmetry of itsatomic arrangement have been shown to be key parameters to controlthe properties of graphene by inducing all this phenomenology.18 Taking these ideas a step further, other approaches,such as adding different elements beneath graphene as another layerof this material or an intercalation layer at its interface with thesubstrate, have also been explored. Interestingly, the addition ofa second layer led to the observation of unconventional Cooper pairingin twisted bilayers, where both graphene sheets are rotated underthe so-called magic angle.19 Likewise,the incorporation of an intercalation layer has induced effects rangingfrom doping, which can be tuned by the electronegativity of the intercalant,21 to the recovery of Dirac cones in cases in which they had been suppressedby the interaction of graphene with the support.23The presence of various defects such asC vacancies25 Reconstruction of thesurface atomic arrangement is very common in semiconductor materialsand less so in metals due to the absence of dangling bonds that increasethe surface free energy.25 However, anunreconstructed bare metal can still experience a surface reconstructiondue to the adsorption of specific atoms and molecules.26 In the present work, this circumstance is exploited to modify grapheneby inducing a surface reconstruction underneath through intercalation,thus taking a step forward in the development of approaches to tunethis 2D material. In particular, a nanostructured graphene systemis obtained by O intercalation between this 2D material and a Rh(110)surface. This metal support was chosen because the chemisorption ofoxygen atoms on it induces a surface reconstruction in the form ofmissing rows to reduce the stress caused by the repulsive adatom–adatominteraction.30 The combination of different characterization methods has revealedthe structural and electronic properties of the resulting nanostructuredgraphene, as well as the local effects of the missing rows underneath,both in the interfacial chemistry and in quasiparticle scattering.This work may pave the way for future investigations, related to thetuning of the properties of graphene or other 2D materials on metals,by taking advantage of the reconstruction of the metal surface uponintercalation of different elements.Surface reconstruction is a phenomenon where a few atoms oftheoutermost layers suffer lateral displacements with respect to theiroriginal positions or undergo a complete transformation of their periodicitywith respect to the bulk.22.12H4) as the precursor molecule. To this end, the Rh(110)single crystal was cleaned through cycles of Ar+ sputteringat 1 keV, followed by annealing at 950 °C at an oxygen partialpressure of 2 × 10–6 Torr, and finished witha flash-annealing in UHV at 950 °C and 1050 °C. Ethyleneexposure was then performed by opening a leak valve, connected toa high-purity source of this gas, at a pressure of 3 × 10–7 Torr for 150 s, while maintaining the Rh(110) substrateat 900 °C.Monolayersof graphene on Rh(110) were grown in situ by chemical vapor depositionunder ultrahigh vacuum (UHV) conditions, using ethylene , microlow-energy electron diffraction (μ-LEED), micro angle-resolvedphotoemission spectroscopy (μ-ARPES), and micro X-ray photoelectronspectroscopy (μ-XPS) experiments, a different approach to graphenegrowth was used to avoid the contribution of different rotationaldomains of graphene on Rh(110) to the total signal.Sample temperature was measured in both experimentalsystems byusing an infrared digital pyrometer.2.22) at a partial pressure of 1 × 10–6 Torr. In scanning tunneling microscopy (STM) experiments, wherea monolayer of graphene covered the entire Rh(110) surface, 3.6 ×103 L was typically required to achieve an intercalatedcoverage of ≈0.4 ML, while during the experiments at the Nanospectroscopybeamline, the dosage used was much lower (900 L) since the isolatedgraphene islands coexist with nearby bare metal regions. This differencein the procedure can be understood as follows: the presence of a fractionof bare Rh(110) surface directly supports the dissociation of molecularoxygen, allowing the intercalation process. On the contrary, thermallyactivated etching31 of the graphene layeris required to create bare Rh(110) regions, where O2 moleculescan dissociate, fostering the intercalation of the resulting O adatomsat the interface between graphene and Rh in neighboring regions.Oxygen intercalationat the graphene/Rh(110) interface was achieved by maintaining thesample at 320 °C during its exposure to molecular oxygen (O2.333 placed in a UHV chamber (basepressure below 10–10 Torr) connected to the adjacentpreparation chamber and delimited by a gate valve. All experimentaldata were measured at room temperature (RT) in the constant currentmode, using electrochemically etched W tips and with the bias voltageapplied to the sample. Data were acquired and post-analyzed usingthe WSxM software.34STM experimentswere performed using a home-built variable temperature scanning tunnelingmicroscope (VT-STM),2.436 at the Nanospectroscopy beamline of the Elettra Sincrotrone TriesteLaboratory. This instrument combines imaging, diffraction, and spectroscopyoperation modes under UHV conditions, using either electrons or photonsas probe sources. The kinetic energy of the electrons emitted or scatteredelectrons by the sample was controlled by the bias voltage appliedto the sample, known as the start voltage. For LEEM measurements,only the zero-order diffraction beam was used for imaging (BrightField). For μ-LEED, ARPES, and XPS data, the imaging area waslimited to a diameter of less than 2 μm using illumination ora field-limiting aperture. The monochromated soft X-ray beam was incidenton the sample at a grazing angle of 16° from the surface plane.36 The energy resolution of Nanospectroscopy beamtime for spectroscopicdata is below 100 meV. ARPES data were collected by acquiring constant-energysurfaces below the Fermi level, with an energy step-size of 0.025eV, and subsequently stacked upon each other. Then, the band structurecan be obtained by cutting along the desired high symmetry directions.All measurements were performed at RT.These techniques were executed using the spectroscopicphotoemission and low-energy electron microscope (SPELEEM),3c(2 ×2) structure with respect to Rh(110). Meanwhile, p2mg, c(2 × 6), c(2 × 8), and c(2 × 10) O/Rh(110) superstructures.30 These types of (1 × n) surface reconstructionsimply that one surface closed-packed row along the [11̅0] directionis missing out of n atomic spacings along the [001]one, and no oxygen atoms are located along the resulting stripes.Considering this, the superstructure observed in c(2 × 2) phase on Rh(110) under the graphenecover, which does not involve substrate reconstruction. In contrast,the stripe patterns in c(2 × 8) and O-c(2 ×16) structures, respectively. Moreover, by using the oxygen arrangementas a fingerprint of the Rh(110) crystallographic direction, informationabout the graphene rotation angle was also derived. 18 It should also be noted that the continuityof the graphene monolayer is not interrupted by the underlying missingrow reconstruction of the substrate (see S1), althoughthe sandwiched superstructure shows a lower apparent height in themissing row areas . Inthis sense, the graphene in these regions seems to behave as a continuousrippling sheet across the surface.To understand the features observedin 29 Furthermore, two distinct areas of graphene can befound when oxygen induces substrate reconstruction: the intercalatedarea (IA) or the missing row (MRA) area, as labeled in To illustrate the above situations,a plausible schematic representationof the atomic arrangement is proposed in p2mg arrangement reported on the bare metal,where the oxygen atoms induce a (1 × 2) missing row reconstructionof the Rh(110) substrate, here the O-c(2 × 2)does not involve any Rh(110) surface reconstruction under graphene.Likewise, O-c(2 × 16) with (1 × 8) surfaceRh(110) reconstruction also differs from the available literaturefor the case of O/Rh(110), since the maximum spacing in the missingrow reconstruction of Rh(110) was reported to be (1 × 5). Therefore,it seems that the graphene layer induces changes in the chemisorptionof oxygen on Rh(110). Such an idea was also conceived in the Gr/O/Ir(111)system,37 where new oxygen phases undergraphene, which do not exist on the bare Ir(111) metal, were reported.Apossible explanation for the observed experimental evidences is givenin the following lines: O adatoms chemisorbed on Rh(110) are negativelycharged due to electron transfer from Rh atoms to the more electronegativeO ones. As a result, there is a repulsive adatom–adatom interaction,which induces stress in the Rh(110) surface, given the fact the Oatoms are bounded to Rh ones in the topmost surface layer. This stressseems to be relaxed via the formation of missing row reconstructionsin the substrate. Nevertheless, when a graphene cover is over theO adatoms, the atomic lattice of this 2D material could receive someof the stress, which otherwise would be completely induced in theunderlying Rh(110) support. It could explain, for instance, why amissing row reconstruction is not needed at low amounts of O intercalationin the case of the O-c(2 × 2) superstructure.The above comparisonwith the case of O on Rh(110) inevitably raisesthe question of whether or not the graphene cover plays a role inthe underlying atomic arrangement. Compared to the O-(2 × 2)The sandwich superstructures involving substrate reconstructionwere those found predominantly under the intercalation parametersused in the present work. A broader perspective can be gained by lookingmore closely at the regions where these oxygen-induced atomic rearrangementsof Rh(110) occur. 39 as well as after the adsorption of various species on other metalsurfaces, such as acetate molecules on Au(110)26 or Si on Ag(110).40 Furthermore,in the present case, all these processes must take place at the interfacebetween graphene and Rh(110) since experimental STM data showed thatthe graphene monolayer was not disrupted between the planar regionsand the new islands . Thisalso proves the strength and stability of graphene to handle suchcomplex atomic rearrangements below. The above description is illustratedby the scheme shown in The measured apparent height ofthe islands is in agreement withthe single-step height of Rh(110), suggesting that they are formedby Rh atoms in the same configuration as in the (110) plane of bulkRh. Moreover, the presence of missing rows also indicates the chemisorptionof oxygen atoms onto Rh(110) within the islands. These two observationscould be rationalized in terms of a rearrangement of Rh atoms ejectedfrom the missing row areas after the adsorption of oxygen, forcingthe former to aggregate together to form new terraces on the Rh(110)facet with the same rectangular configuration. Analogous phenomenahave been observed for O on bare Rh(110),ands see S2. Thisn) periodicity of the missing row reconstruction of Rh(110)seemsto follow a random distribution over the entire surface, ranging from n = 4 to n = 12. Therefore, the O-c(2 × 8) and O-c(2 × 16) phasesdescribed in c(2 × 2n),with n = [4–12], are found only locally, andthe surface is characterized by a long-range aperiodicity. In otherwords, in this case, graphene could be considered as a one-atom-thicksheet of carbon atoms that ripples aperiodically over the entire surface.Based on the above results, it could be pointed out that the formationof the missing rows across the sandwiched superstructures would havea certain stochastic character due to the fact that the different(1 × n) missing rows, with 12 > n > 4, are thermodynamically allowed. Nevertheless, it seems thatthere must be some interaction between the missing rows since no (1× n) rearrangements for n <4 are found. Furthermore, it cannot be excluded that the distributionof the missing rows along the [001] direction of Rh could be influencedby some defects that could be created during the growth of grapheneor the intercalation of oxygen. In addition, no experimental evidencewas found for a possible effect of the rotational domains of grapheneon the periodicity of the missing row reconstruction.As already can be seen in Once thestructural properties of the sandwiched Gr/O/Rh(110) nanostructureswere established, the electronic properties of the system were alsoinvestigated. Such studies have been focused on regions where oxygeninduces substrate reconstruction under graphene since these are themost commonly found. 42 Thus, the features observed in 42 could also indicate a higher level of graphene interactionin the present case with O/Rh(110) underneath. Furthermore, despitethe rippling character of graphene induced by the presence of bothIA and MRA below, the fact that such patterns can be imaged in thesetwo regions  suggeststhat the graphene monolayer does not exhibit dissimilar electronicproperties in these regions. This could be tentatively explained bythe fact that the intercalation of oxygen atoms on the IA might besufficient to allow the decoupling of the entire graphene sheet fromthe Rh(110) surface in this specific region and also in the MRA. Itis noteworthy to mention that intervalley scattering patterns, similarto those observed in 43 It appears that although the graphene layer is not interrupted acrossthese boundaries, they induce quasiparticle scattering processes thatare not produced by the MRA.A direct explanation for the originof these patterns, observedin the STM images of see also S3 suggesFor a more comprehensive characterizationof the Gr/O/Rh(110) nanostructures,the results presented and discussed above are complemented by LEEM,μ-LEED, μ-ARPES, and μ-XPS data. 18 This suggests that the darker regions in theLEEM image are related to oxygen intercalation, while the other regionsare not intercalated. Furthermore, the appearance of a new featurein the LEED pattern shown in 18 reinforces thishypothesis. The diffuse path, highlighted by the dashed magenta rectangle,is aligned with the Rh[001] direction in the reciprocal space andshows a stronger intensity near the  spot. Such a feature isconsistent with the coexistence of different (1 × n) substrate reconstructions of Rh(110) under graphene, after theoxygen intercalation, in agreement with the STM measurements summarizedand discussed in First, as shown in K of the graphene first Brillouin zone and centered on K (see the blue line in vF) and the Diracpoint (ED) can be determined. Such a fittedresult is represented by the two superimposed red lines, yieldingan approximate value of vF = 1.0 ×106 ± 2 × 105 m/s and ED – EF = 0.4 ±0.1 eV. Details about the employed fitting procedure can be foundin Figure S4. For completeness, the grapheneband structure projected along other high symmetry directions of thegraphene first Brillouin zone is shown in Figure S5. Similarly, using a photon energy of 400 eV, the C 1s corelevel spectrum of graphene is shown in On the same island, wherethe μ-LEED shown in 46 However, in the caseof Gr/O/Rh(110), the Dirac point is above the Fermi level. In fact,the graphene layer shows a hole doping 22 system. However, it differs from the STS data obtained for oxygenintercalated on Gr/Rh(111)23 or Gr/Ru(0001).47 The absence of crossings of Rh(110) states withthe graphene π band, which is present in as-grown graphene onRh(110)18 suggests that, upon oxygen intercalation,the graphene layer is efficiently decoupled from Rh(110) and no furtherhybridization with the metal 4d states is expected, consistent withthe analysis of graphene quasiparticle scattering results shown in The estimated value for the Fermivelocity of graphene quasiparticlesis in agreement with the theoretical and experimental values of afree-standing graphene monolayer.18 wherethe C 1s spectrum is described by two components with a binding energyof 284.9 and 284.4 eV, implying a significant interaction of graphenewith the metal, the C 1s core level of graphene after oxygen intercalationbelow is characterized by a general shift toward lower binding energy,with a dominant peak at 284.0 eV and another one, with a more modestcontribution to the C 1s line shape, at 284.4 eV. Such an energy shiftis in qualitative agreement with the p-doping levelof graphene, as demonstrated by the μ-ARPES data shown in 48 and it is also consistent with other previouslyreported experimental results.49 Thus,the core level shift of the main component of the C 1s signal observedin the present case provides a solid fingerprint of oxygen intercalationunder graphene. As shown in S6). However, a contribution to the componentat 284.4 eV coming from MRA whose C atoms do not have oxygen atomsunderneath them but are still lifted with respect to the metal substratecannot be excluded.Comparedto graphene on Rh(110),4c(2 × 2), which does not involve any reconstructionof Rh(110), and a mixture of O-c(2 × 2n) phases with (1 × n) Rh(110) substratereconstruction as missing rows, where n ranges from4 to 12. The latter structure was the predominant one found in thisoxygen-sandwiched system, and it is characterized by an aperiodicmodulation of graphene over the surface due to the coexistence ofdifferent (1 × n) reconstructions within a narrowzone. The resulting aperiodic nanostructured graphene consists oftwo distinct regions, namely, the intercalated area (IA) and missingrow area (MRA). Joint STM-based quasiparticle interference analysisand μ-ARPES and μ-XPS data obtained in the missing rowreconstructed regions show that the graphene is efficiently decoupledfrom the Rh(110) substrate and exhibits the characteristic lineardispersion of graphene, albeit with p-doping. Furthermore,the experimental data do not support a significantly different chemicaland electronic landscape on IA and MRA. These results could open aninnovative method of graphene nanostructuring via the intercalationof species that induce surface reconstruction.By combiningdifferent imaging, spectroscopy, and diffraction techniquesunder UHV conditions, the structural and electronic properties ofaperiodically modulated graphene monolayers have been investigated.Such a nanostructured system was realized by the intercalation ofoxygen at the interface of graphene grown on Rh(110). Oxygen atomsunder graphene form two types of superstructures with respect to Rh(110):the O-


The ubiquitin-proteasome pathway controls the monitoring and degradation of important proteins and is involved in several cellular processes, such as development, differentiation, and transcriptional regulation. Recent evidence has shown that ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1), a member of the deubiquitinating enzyme family that removes ubiquitin from protein substrates, is overexpressed in many types of cancer.This study thus examined the expression of UCH-L1 in human astrocytoma tissues.Formalin-fixed, paraffin-embedded astrocytoma samples were obtained from 40 patients, after which histopathological examination, typing, and grading were performed. The study group included 10 histologically normal brain tissues, which served as the control group, and 10 WHO grade II, 10 WHO grade III, and 10 WHO grade IV (glioblastoma) samples. Normal brain tissue samples were obtained from the histologically normal, non-tumoral portion of the pathology specimens. UCH-L1 expression was evaluated using quantitative reverse transcription-polymerase chain reaction and immunohistochemistry.Astrocytoma tissues exhibited higher UCH-L1 expression compared to the control group. UCH-L1 overexpression increased significantly together with the increase in astrocytoma grades (from II to IV).UCH-L1 could be a good diagnostic and therapeutic marker for determining astrocytoma development and progression. The knowledge about the molecular basis of astrocytoma development and progression has increased significantly, especially in the last decade. They are graded in the sixth version of World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS) as the international standard for the classification of brain and spinal cord tumors.Astrocytomas are the most common intrinsic central nervous system neoplasms, particularly in adults. They are the most aggressive primary brain tumors and those with the poorest vital prognosis.Ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1) belongs to the deubiquitinating proteases family that removes ubiquitin from protein substrates and precursor proteins. Deubiquitinating proteases are involved in abundant biological processes in cells like development, differentiation, and transcriptional regulation. pancreatic endocrine tumors, and non-small cell lung cancer. Previous studies showed the constitutive expression of UCH-L1 in human neural cell lines. Studies of traumatic brain injury also showed that UCH-L1 expression was increased according to the severity of trauma and that it indicates a poor outcome.Besides its biological roles, UCH-L1 was suggested to be a crucial regulator of invasion and metastasis in various types of cancer including neuroblastoma,In this study, we examined the expression of UCH-L1 in human astrocytoma tissues with quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemistry for the first time in the literature. The study group included 10 histologically normal brain tissue samples, which served as the control group, 10 WHO grade II, 10 WHO grade III, and 10 WHO grade IV (glioblastoma) samples. Normal brain tissue samples were obtained from the histologically normal non-tumoral portion of the pathology specimens. None of these patients were administered radiotherapy, chemotherapy, or immunotherapy prior to their surgery. Informed consent and ethical approval for the study were obtained. Ethical approval for this study was obtained from the relevant institutional review board with date 05/01/2018 and number 2018/1148 , ensuring that the research protocol adheres to established ethical guidelines and safeguards the rights and welfare of the participants.Surgically resected astrocytoma specimens from 40 patients who underwent surgery at our institute between 2005 and 2017 were obtained from the pathology archive. The specimens had been fixed in 4% phosphate-buffered formaldehyde, after which they had been processed into paraffin blocks. Histopathological examination, typing, and grading of the hematoxylin and eosin-stained slides were performed. Amplification reactions were set up in a reaction volume of 20 μL using the LightCycler 480 PCR Master Mix . PCR primaries and TaqMan probes  were synthesized and preoptimized. qRT-PCR was performed using PCR primaries  and TaqMan probes in the LightCycler 480 II system (Roche Applied Science). The following primers were used: UCHL1-F 50-CCTGAAGACAGAGCAAAATGC-30; UCHL1-R 50-AATGGAAATTCACCTTGTCATCT-3. Amplification was performed for 40 cycles at 95°C for 10 seconds, followed by 60°C for 30 seconds, and 72°C for 1 second. Quantification was achieved using the comparative CT method, normalizing against the 18S ribosomal RNA (18S) gene. The expression levels in tumor tissues relative to the non-tumor controls were assessed using the 2 −ΔΔCt method. Briefly, the threshold cycle (Ct) of fluorescence for each sample was determined. ΔCt indicates the difference in expression levels between UCH-L1 and 18S(ΔCt = Ct UCHL1 − Ct18S), and ΔΔCt indicates the difference in the ΔCt value between the tumor tissue and the control (ΔΔCt = ΔCttumor − ΔCtcontrol). The 2−ΔΔCt value  was calculated.Ribonucleic acid (RNA) isolation and qRT-PRC evaluation were completed in a standard fashion. Total RNA was isolated from formalin-fixed, paraffin-embedded (FFPE) tissues using the High Pure FFPET RNA Isolation Kit  according to the manufacturer’s instructions. The Transcriptor First Strand c-DNA Synthesis Kit (Roche Applied Science) was used to generate c-DNA from RNA, according to the manufacturer’s instructions; 10 μL total RNA was used for amplification.Paraffin-embedded tissue samples were extracted and sectioned (4 µm thickness), and then mounted onto positively charged slides .The procedure was performed using an automated avidin-biotin system  employing the PGP 9,5 antibody .Cytoplasmic immunoreactivity patterns were evaluated and categorized as negative 0, weak 1, moderate 2, or intense 3 positives.U test with Bonferroni correction. A P value of less than .05 was considered statistically significant.Statistical analyses were performed using SPSS for Windows 18.0 . The data were expressed as median or mean ± standard deviation (SD). The statistical comparisons of the groups were performed by the Kruskal–Wallis test. The significant results for pairwise comparisons were analyzed by the Mann–Whitney P < .001). All results of the groups were significantly different from each other (P < .05).The mean changes in the mRNA level of UCH-L1 in astrocytoma, relative to control tissue, were 52.06 ± 17.14 for grade II, 233.26 ± 18.37 for grade III, and 658.50 ± 84.44 for grade IV. The difference in the groups was found to be statistically significant . Immunostaining positivity increased statistically significantly (P < .008) according to ascending grades from grade II to IV. Representative hematoxylin and eosin and UCH-L1 immunostaining images are presented in Figure All astrocytoma tissues showed statistically significant high cytoplasmic immunoreactivity compared to the control group  pathway are 2 important pathways that control protein monitoring and degradation. It was also shown that UCH-L1 is a key regulator of tumor invasion and metastasis.Recent evidence has verified the overexpression of UCH-L1 in many types of cancer including but not limited to acute lymphoblastic leukemia, non-small cell lung cancer, neuroblastoma, pancreatic, prostate, and medullary thyroid cancers.Studies concerning the molecular basis of astrocytoma development and progression increased significantly, especially in recent years. In the present study, we analyzed the expression of UCH-L1 in surgically resected astrocytoma tissues from several grades using qRT-PCR and immunohistochemistry methods for the first time in the literature. Our results showed that UCH-L1 was overexpressed in astrocytoma tissues when compared with a control group acquired from the non-tumoral portion of the pathology specimens. UCH-L1 overexpression was significantly increased according to ascending grades of astrocytoma samples from grade II to IV.Selective degradation of proteins by the UPS pathway is a critical determinant for providing cellular homeostasis. The UPS degradation pathway plays an essential role in both the up-regulation of cell proliferation and the down-regulation of cell death in human cancer cells. and solid tumors has attracted great attention with several rates of success reported. Previous studies showed the clear distribution of UCH-L1 in the brain which constitutes up to 5% of total neural proteins. It was shown that UCH-L1 is not essential for neuronal development but it is precisely necessary for the preservation of axonal integrity. Dysfunction of UCH-L1 was also implicated in the pathogenesis of various neurodegenerative diseases.Targeting the ubiquitin-proteasome system in hematological malignancies The capacity of the proteasome for impairment of tumor-suppressing and proapoptotic protein targets is known to be dysregulated in many human malignancies, providing the reason for choosing the proteasome as a target for cancer treatment.The proteasome complex modulates the activity of important substrates which administrate cell proliferation, apoptosis, angiogenesis, and metastasis, such as tumor suppressor protein p53 and transcription factor nuclear factor kappa-B. investigated the inhibitory effects of proteasome antagonist carfilzomib on glioblastoma cell proliferation, migration, and invasion and reported that the second-generation proteasome inhibitor carfilzomib should be considered a potential therapeutic agent for the treatment of glioblastoma.Areeb et al According to our literature search, we could not find any study which investigates the UCH-L1 expression profile in astrocytoma. UCH-L1 regulates many signaling pathways and could induce cancer cell invasion and metastasis due to its post-translational deubiquitinating activity.The role of UCH-L1 in oncogenesis and specific targets in the deubiquitinating process have yet to be determined.Astrocytoma constitutes a major part of the human intrinsic central nervous system neoplasms. The most common form of this neoplasm is glioblastoma which currently has no curative treatment. In this study, we found overexpression of UCH-L1 in astrocytoma tissues according to ascending grades. We suggest that UCH-L1 might be a good diagnostic and therapeutic target for checking astrocytoma development and progression.Conceptualization: Emir Kaan İzci, Fatih Keskin.Formal analysis: Fatih Erdi, Bulent Kaya, Bahadir Feyzioglu.Investigation: Yasar Karatas, Siddika Findik.Methodology: Emir Kaan İzci, Erdal Kalkan, Önder Güney.Software: Hasan Esen.Validation: Fatih Erdi, Bulent Kaya.Visualization: Fatih Keskin, Önder Güney.Writing – original draft: Yasar Karatas, Bahadir Feyzioglu, Hasan Esen.Writing – review & editing: Emir Kaan İzci.


Periprosthetic joint infection (PJI) is a devastating complication following joint replacement, associated with morbidity and mortality. Here, we established a clinically representative murine model of knee arthroplasty and determined the ideal bacterial inoculum that would result in PJI without causing significant limb compromise.Staphylococcus aureus Xen36, ranging from 29 to 14,000 colony forming units (CFU) (Table 1). Mice were sacrificed at 3 weeks, or earlier if necessary due to infectious sequelae, and the joint tissue, tibia, femur, and prosthesis quantitatively cultured.A titanium tibial prosthesis designed for the murine knee was 3D printed and surgically implanted into the proximal tibia  of 38 C57BL/6 mice. The prosthesis is designed to osseointegrate into the tibia and has a smooth articular surface to allow for immediate weight bearing and range of motion. At the time of surgery, the arthroplasty was inoculated with five inocula of All mice inoculated with 181 to 14,000 CFU developed PJI as did 90% inoculated with 29 CFU. Bacterial loads from joint tissues and tibial prostheses are shown in Table 1. All mice inoculated with 14,000 and 760 CFU had overt findings of infection  requiring early euthanasia (Table 2). Mice inoculated with 640 CFU had swelling, redness, and small sores in first 3 days, and 1 death, but otherwise appeared well; only 2/9 had a visible abscess at 3-week sacrifice. 2/10 mice receiving 181 CFU had small sores that resolved in the first week; all limbs functioned well prior to sacrifice. Mice receiving 29 CFU had no external evidence of infection, however 9/10 had purulence within the joint at sacrifice.S. aureus PJI. An inoculum of 181 CFU resulted in universal infection without significantly compromising the limb. The ability of this model to create PJI without overt infectious sequela will allow for evaluation of therapeutics, including those locally delivered.This study demonstrates that inoculum size directly impacts clinical manifestations of infection in a murine model of Robin Patel, MD, Abbott Laboratories: Advisor/Consultant|Adaptive Phage Therapeutics: Grant/Research Support|Adaptive Phage Therapeutics: Mayo Clinic has a royalty-bearing know-how agreement and equity in Adaptive Phage Therapeutics.|BIOFIRE: Grant/Research Support|CARB-X: Advisor/Consultant|ContraFect: Grant/Research Support|Day Zero Diagnostics: Advisor/Consultant|HealthTrackRx: Advisor/Consultant|Mammoth Biosciences: Advisor/Consultant|Netflix: Advisor/Consultant|Oxford Nanopore Technologies: Advisor/Consultant|PhAST: Advisor/Consultant|See details: Patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic|See details: continued, patent on an anti-biofilm substance issued|TenNor Therapeutics Limited: Grant/Research Support|Torus Biosystems: Advisor/Consultant|Trellis Bioscience, Inc.: Advisor/Consultant Nicholas Bedard, MD, Stryker: Advisor/Consultant


This work demonstrates the green production of a graphene ink for inkjet printing and its use as a hole transport layer (HTL) in an organic solar cell. Graphene as an HTL improves the selective hole extraction at the anode and prevents charge recombination at the electronic interface and metal diffusion into the photoactive layer. Graphite was exfoliated in water, concentrated by iterative centrifugation, and characterized by Raman. The concentrated graphene ink was incorporated into inverted organic solar cells by inkjet printing on the active polymer in an ambient atmosphere. Argon plasma was used to enhance wetting of the polymer with the graphene ink during printing. The argon plasma treatment of the active polymer P3HT:PCBM was investigated by XPS, AFM and contact angle measurements. Efficiency and lifetime studies undertaken show that the device with graphene as HTL is fully functional and has good potential for an inkjet printable and flexible alternative to PEDOT:PSS. Organic photovoltaics (OPV) belongs to the area of thin-film technologies of solar cells and had its beginnings in the early 1990s, where mostly fullerene derivates were used for the active layer ,7,8,9,10Organic semiconductors can be processed in solution ,20,21. TDepending on the different geometries and photoactive layers used, different materials can prolong the lifetime and stability of the solar cell . For example, commonly used ETL materials include ZnO or modified ZnO in inverted organic solar cells (OSCs)  and, rec3 and transition metal disulfides or other oxides [HTLs used in organic solar cells include poly polystyrene sulfonate (PEDOT:PSS) ,43,44,45r oxides ,46,47. Ur oxides ,46.Graphene has also been heavily investigated for applications in OPV. Several publications have reported the usage of graphene in organic solar cells, mostly used as graphene oxide or composites, and for solar absorbers ,49,50,51In the case of an inverted structure b, the stIn this work, we tested liquid phase exfoliated (LPE) graphene material as an HTL , taking A quantity of 12 g/L of natural graphite flocks was exfoliated by liquid phase exfoliation (LPE) in water with 9 g/L sodium deoxycholate (SDC). Subsequently, the dispersion was ultracentrifuged, and the supernatant collected was the graphene standard ink. Iterative centrifugation was used to concentrate the graphene ink. The concentration of the dispersions was determined by optical absorption spectroscopy (OAS) with absorption coefficient α = 1390 L/g·m at 660 nm . A finalRaman spectra were acquired at 457, 514 and 633 nm using a Renishaw InVia spectrometer  equipped with a 100× objective (N.A. = 0.85). Ca. 20 spectra were collected for statistical analysis.Graphene solar cell devices were prepared by inkjet printing graphene on an ITO/ZnO/poly(3-hexylthiophene mixed with a phenyl-C-61-butyric acid methyl ester (P3HT:PCBM) stack, which was made by doctor-blade-coating under ambient conditions. Laser-structured substrates of ITO were cleaned with a sequence of successive baths in acetone and IPA. The ZnO layer (ZnO suspension from Ibu Tec) was blade-coated and annealed for 5 min at 130 °C in air. The active layer was created by mixing P3HT with PCBM (both from Merck) 1:0.8 weight ratio in o-xylene and tetrahydronaphtalene with a ratio of 9:1. For reference cells, PEDOT:PSS (1:3 Clevios HTL-388:IPA) was doctor-bladed as an HTL with a temperature of 65 °C and annealed at 130 °C for 5 min in an inert atmosphere. Ag (100 nm) was evaporated at a standard rate of 1–5 Å/s.2 scans with the average value from three different samples taken. XPS measurements were carried out on a Theta Probe XPS system  using a monochromatic Al-Kα X-ray Source with a photon energy of 1486.6 eV. For survey scans and high resolution (HR) scans, the hemispherical analyzer was set to a pass energy of 200 eV and 20 eV. The energy step sizes were 1 eV and 0.05 eV, respectively.Before printing, the surface of the substrate was exposed to argon plasma in a “nano” plasma asher from Diener electronic GmbH & Co.KG . The plasma-treated P3HT:PCBM surface was characterized by the surface free energy (SFE) and contact angle (CA) using a Krüss DSA 100 goniometer. SFE was calculated from the measured contact angles of water, diiodo-methane, and ethylene glycol. Atomic force microscopy (AFM) measurements using a Bruker Dimension Edge operated in tapping mode were used to acquire the surface topographics. The surface roughness was calculated from 20 × 20 µm2O:ethanol 1:1 solution for few seconds. Transmission electron microscopy (TEM) measurements were performed with a JEOL JEM-2011  equipped with a LaB6 filament. Images were taken with a Gatan Slow-Scan CCD Camera Model. For the energy-dispersive X-ray spectroscopy (EDX) measurements, a JEOL JEM-2200FS TEM equipped with an OXFORD Instruments EDX system with an SDD Detector  was used.The graphene ink was printed in an ambient atmosphere, but in rooms with UV-reduced light conditions, on the pre-fabricated ITO/ZnO/P3HT:PCBM substrates with a Dimatix Printer DMP-2831 from FUJIFILM Dimatix, Inc.  and a drop volume of 10 pl, with a drop space of 65 µm. After printing, the stabilizing surfactant SDC was removed by rinsing with a mixture of H2, 1 Sun intensity) and measured with a Keithley 2400 source meter in combination with a Keithley 7001 Multiplexer system.The current–voltage characteristics of the solar cells were recorded under a calibrated Oriel solar simulator with a xenon lamp  chamber, encapsulated under open-circuit conditions. The climate conditions were set to 85 °C and 85% relative humidity (rH). For every measurement, the samples were taken out of the chamber, allowed to cool, and measured in an inert atmosphere with the solar simulator.−1, and the full width at half maximum FWHM(2D) was ~64 cm−1. The I(2D)/I(G) /I(G) b ranged −1/nm was much lower than the value expected for disordered carbon [The Raman spectra showed significant D and D′ peak intensities, with I(D)/I(G) ranging from 0.7 to 2.3. However, the value of the rate of change of the G peak position with excitation wavelength Disp(G) of ~0.006 cmd carbon . Therefod carbon . This obrmsR) showed no significant difference for all substrates and was 12.2 ± 1.0 nm, 12.5 ± 3.1 nm and 13.7 ± 1.8 nm for untreated, mild plasma-treated and plasma-treated P3HT:PCBM substrates, respectively, which is in accordance with the literature [The as-prepared graphene ink was used as the HTL of the organic solar cells with an inverted device configuration of ITO/ZnO/P3HT:PCBM/graphene/Ag compare b. The soterature ,78. XPS terature ,80. SolarmsR from 12.5 nm of the mild plasma-treated P3HT:PCBM substrate to 23.6 ± 0.8 nm for 10 inkjet printing passes of the graphene ink and of 19.1 ± 1.9 nm for 20 printing passes, respectively. Interestingly, the roughness of the graphene film could be reduced slightly by printing more layers. This was attributed to a more homogenous distribution of printed graphene flakes on the substrate. The transparency of the printed graphene film on P3HT:PCBM was measured by OAS. The value obtained at 550 nm was ~75–80%.AFM measurements taken of the inkjet-printed graphene film showed an increase in the After the deposition of the Ag top electrode, the morphology of the unencapsulated finished solar cells with graphene film as an HTL was investigated with transmission electron microscopy (TEM). J-V curves.Different cells with printed graphene as an HTL were fabricated with an increasing number of printing passes from 10 up to 20. Control devices with PEDOT:PSS (doctor-bladed) as the HTL were also fabricated under identical conditions. The photovoltaic performances of these devices are summarized in J-V curves showed that the samples with graphene suffered from lower parallel resistances than the reference. This points to small pinholes in the graphene layer where the top Ag electrode can have a direct contact with the active layer; however, no direct trend with printing passes could be detected. The best performance was achieved with 15 passes and a maximum efficiency of 2%. The appearance of an s-shape in the J-V curves from the graphene samples with 10 and 20 printing passes was notable. As shown by these data, the performance of the solar cells changed with the number of printing passes of the graphene ink, although none of the graphene cells could reach the reference cell with PEDOT:PSS. Measured dark SCJ and OCV values as the device with 15 printing passes; however, the FF was lower. This indicates that a thinner layer of graphene material results in lower conductivity, resulting in a higher series resistance Rs which lowers the FF [J-V curve may be due to no good current transport.The devices with 10 printing passes of graphene showed similar s the FF . MoreoveSCJ-value of the device with 20 printing passes of graphene was remarkably high at 10 mA/cm2 compared to the reference device. The thicker graphene layer probably promotes an optical spacer effect [The r effect ,83, but 2 lowers the hole concentration in suspended CVD graphene. Ideally, the work function of the HTL material should be ca. −5.0 eV for proper charge transport. Measurements with a Kelvin probe set-up (Single Point Kelvin Probe set-up from KP Technology) showed a work function of the inkjet-printed graphene on ITO of −4.88 ± 0.036 eV. In the literature, tuning of the work function of graphene is described, e.g., via changing the electrical field and using the electric field-effect ,85, expoJ-V curves and degraded very fast, whereas the lifetime of the cells with graphene seemed to be unaffected by the pre-treatment itself  before the application of PEDOT:PSS. Interestingly, these cells showed very poor characteristic  compare a. This m compare .SCJ, OCV, FF under DH storage. The use of deeply studied materials (ITO/Zn/P3HT:PCBM/PEDOT:PSS/Ag) as a reference was advantageous for comparing the degradation.OCV , the RS for the reference sample continuously increased from an initial average value of 2.7 Ω cm2 to 62.7 Ω cm2 after 645 h in the harsh damp heat conditions. This could be the reason for the drastic failure of the J-V curves of the reference samples beginning after 474 h  than that between the semiconductor and PEDOT:PSS. It has to be taken into account that almost 90% of all the tested cells with graphene were still functioning at the end of the lifetime testing, whereas half of the reference solar cells had completely degenerated.All these findings show that in liquid, exfoliated graphene is a prospective hole-transport layer, which shows potential to increase stability in OPV cells. However, to achieve reliable results, the SDC has to be decreased in the final printing solution or the washing process has to be improved. A solution could be to replace all, or at least part, of the SDC with additives, which can also act as p-dopants, to slightly increase the work function and the hole concentration of the graphene.A water-based graphene ink was produced via ultrasonication. By centrifugation, the ink was purified from large graphite particles and subsequently concentrated to 1 g/L. The concentration was confirmed by optical adsorption spectroscopy and the graphene flakes were characterized by Raman.It was shown that water-based graphene ink can be easily inkjet printed on Ar plasma-treated P3HT:PCBM substrates for usage as an HTL in inverted structure organic solar cells. The procedure described in this work has enabled, for the first time, the production of working solar cells with inkjet-printable graphene (not graphene oxide) as the HTL. The solar cells showed a similar long-term stability as solar cells with commercial doctor-bladed optimized PEDOT:PSS when no encapsulation was used. In particular, the persistence of the series resistance for more than 640 h shows the high potential for improving the stability performance of organic solar cells with graphene. This study indicates that printed graphene flakes produced by exfoliation in green solvents without the use of toxic and critical components can serve as a stable, low cost and flexible alternative, allowing the production of fully inkjet-printable organic solar cells.J-V tests, and in-depth work on work function improvement and investigation of graphene flakes (including doping experiments), will follow in the future. Light intensity tests would enable checking the effects of several factors, i.e., if a lower FF is just due to low Rs  or if other factors play a role . Additionally, graphene as an HTL will be tested on current ternary semiconductor systems, such as PM6:Y6:PCBM.After initial tests to assess the potential of the graphene flakes and first lifetime tests, further in-depth tests, such as light-intensity-dependent


The GTr’s ecological benefits, combined with its excellent printability and good conductivity, make it an ideal candidate for manufacturing chemiresistive sensors that can be used for Internet of Things (IoT) healthcare and environmental applications.This study presents graphene inks produced through the liquid-phase exfoliation of graphene flakes in water using optimized concentrations of dispersants . The study explores and compares the effectiveness of the three different dispersants in creating stable and conductive inks. These inks can be printed onto polyethylene terephthalate (PET) substrates using an aerosol jet printer. The investigation aims to identify the most suitable dispersant to formulate a high-quality graphene ink for potential applications in printed electronics, particularly in developing chemiresistive sensors for IoT applications. Our findings indicate that triton X-100 is the most effective dispersant for formulating graphene ink (GTr), which demonstrated electrical conductivity (4.5 S·cm The growing interest in printed and flexible electronics for Internet of Things (IoT) applications has led to a surge in research on high-performance conductive inks . As the −2 and Hansen solubility parameters (HSPs) of 18, 9.3, and 7.7 MPa1/2 for the dispersive (δD), polar (δP), and H-bond (δH) parameters, respectively  and K4[Fe(CN)6] in 10 mM phosphate-buffered saline ) on the active area of an electrochemical cell. Blank measurements were taken for calibration before the graphene deposition. The CV measurements were carried out at a constant scan rate of 20 mV·s−1 from −400 V to 700 mV for 10 cycles, while the SWV curves were recorded from −100 mV to 600 mV. EIS was performed over a frequency range of 100 Hz to 200 kHz at an amplitude of 50 mV. The real and imaginary components of the complex impedance were denoted as ZRe and ZIm, respectively. All experiments were conducted at room temperature.Electrochemical analysis techniques such as cyclic voltammetry (CV), square-wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) were performed to investigate graphene’s electrochemical activity using a three-electrode Biologic SP-200 potentiostat  with the EC-Lab software. The adsorption of dispersants on the surface of the graphene flakes can influence their electrochemical activity. CV and SWV were used to analyze the kinetics of the electrodes, while EIS was used to investigate the interfacial characteristics of the graphene layer . The ele2 (inert), H2S (acidic and electron-withdrawing molecule), and NH3 (basic and electron-donating molecule) gases. The measurements were taken after a 1 h pause between gas insertions, and sensor recovery was evaluated by exposing the sensors to room-temperature air after opening the chamber’s lid.Additionally, EIS was performed to investigate the conduction process of graphene nanostructures with gases using a two-electrode system . The EIS for graphene gas sensors was investigated with exposure to NThis study aims to synthesize graphene inks by exfoliating graphene directly from raw graphite into the water, which is considered the most environmentally friendly solvent. However, graphene is not readily dispersible in water due to the significant differences in their respective HSPs and surface tension . To addr−1 graphite concentration in 10 mL DI water and measured the optical absorbance at 660 nm to determine the concentration of exfoliated graphene. −1 and 1.5 mg·mL−1 led to a maximum graphene concentration of 0.11 mg·mL−1, representing 20% of the initial graphite mass successfully exfoliated. The rest (80%) remained unexfoliated at the bottom of the dispersion. Triton X-100 required 1 mg·mL−1 to achieve the highest graphene concentration, while tween-20 needed 50% more (1.5 mg·mL−1) to achieve the same concentration, suggesting that triton X-100 is more effective at adsorbing on the surface of graphene than tween-20. Above 1 mg·mL−1 and 1.5 mg·mL−1 for triton X-100 and tween-20, respectively, the graphene concentration decreased due to the depletion flocculation mechanism [−1 to 5 mg·mL−1 had no discernible effect on increasing the graphene concentration beyond 0.05 mg·mL−1 (2.2 times less than the dispersion with triton X-100 and tween-20). We assumed that the graphene surface was saturated at the optimal dispersant concentrations, which optimized the size of the potential barrier surrounding the flakes for the best stabilization [−1, 1 mg·mL−1, and 1.5 mg·mL−1 for gelatin, triton X-100, and tween-20, respectively, to prepare the graphene inks denoted as GGe, GTr, and GTw. Notably, the dispersant concentrations used in this study were considerably lower than those applied in developing graphene ink (>10 mg·mL−1) [The concentration of dispersant used and the surface coverage of the graphene flakes are key factors in achieving stable graphene dispersions with high concentration and good electrical performance ,51. Therechanism ,51. In clization ,51. Ther−1) at pH 6.4, the zeta-potential for GTr and GTw was found to be −38.5 mV, while for GGe it was −41.5 mV. The greater zeta-potential for GGe can be attributed to the contribution of both steric and static stabilizing mechanisms. The negative zeta-potential indicates that the net surface charge of the graphene flakes is negative, and the zeta-potential values are sufficient to prevent graphene flakes from precipitating, ensuring stable dispersions.Graphene in aqueous solutions develops a zeta-potential, which refers to the potential and electric double layer formed at the interface and is highly associated with dispersion stability . A high DLS and TGA techniques were employed to better engineer the graphene dispersions’ qualities in order to evaluate the effect of the dispersants’ properties and purification steps involving centrifugation at 1 k and 14 k rpm. Controlling the flake size distribution is crucial to avoid nozzle clogging and complications during printing. Additionally, the dispersant-to-graphene ratio, which determines the surface coverage of graphene flakes by dispersants, is critical for optimizing charge transport in graphene films , and flaDLS was used to assess the flake size distribution of the inks as a large-scale evaluation of the mean flake size in the graphene dispersion. After the first purification stage involving centrifugation at 1 k rpm for 30 min, graphene dispersions exhibited a diameter distribution range of 50 nm to 800 nm B, with oAfter the second purification process (centrifugation at 14 k rpm for 2 h), the flake size distribution of the final graphene dispersions obtained had shrunk to 100–800 nm, and significant changes were observed in the flake distribution for each sample, as outlined in These results suggest that the type of dispersant used can influence the flake size distribution. It was also observed that the second purification process effectively eliminated graphene flakes > 400 nm from the GTr and GTw inks, resulting in more symmetrical DLS curves. These findings highlight the importance of carefully controlling the dispersion and purification of graphene to optimize its properties for various applications, particularly as nanofillers in printed films, where smaller flakes can improve charge transport and increase electrical conductivity.The morphological properties of the graphene samples were investigated using AFM and TEM, as shown in One consistent observation in the AFM images was the presence of a coating of deposited dispersant-like residue on the graphene and mica substrate surfaces. These coatings achieved a height of 10 nm on top of the mica substrate with GTr . AdditioThe TEM images in Our TEM images showed that the GGe sample had large dark areas identified as piled gelatin . The TEMTo evaluate the impact of purification on the dispersant-to-graphene ratio and graphene’s thermal characteristics, we conducted TGA and DTG analyses. As shown in The final inks shown in A,B under−1, which remained stable with excellent dispersity even after being stored for over a month. Using an AJP, we deposited the graphene inks onto a flexible PET substrate, producing thin films  at concentrations of 3 mg·mLin films A–C afterThe inks flowed smoothly through the nozzle during printing without requiring additional modifications to control their properties, such as viscosity, surface tension, printing flow, or rheology modifiers. To assess their performance characteristics, we evaluated the printability, wettability, and electrical behavior of the graphene inks as a function of the type of dispersant used. These inks appear to have promising potential considering the two essential performance characteristics that ink should have: good printability and printing definition.The films’ thicknesses increased as the printing passes increased, with an average layer thickness of ≈32 nm. −1), where ρ was calculated from the multiplication of Rs and t [−1, 2 S·cm−1, and 1 S·cm−1 for GTr, GTw, and GGe, respectively.In terms of the electrical behavior, thicker films had lower sheet resistance (Rs), settling at 7.5 kΩ/□, 3.6 kΩ/□, and 2.6 kΩ/□ for GTr films at 500 nm, 800 nm, and 1.15 µm, respectively. For GTw films, Rs settled at 14.4 kΩ/□, 7 kΩ/□, and 5 kΩ/□ for thicknesses of 500 nm, 800 nm, and 1.15 µm, respectively, which is approximately double the Rs recorded for GTr films with the same thicknesses. GGe films had the highest sheet resistance, with 27 kΩ/□, 17 kΩ/□, and 14 kΩ/□ for film thicknesses of 500 nm, 800 nm, and 1.15 µm, respectively. The conductivity (σ) was calculated using the reciprocal of resistivity (ρ)  like ethyl cellulose (EC) were required in these inks, which can create nanofillers of conjugated structures between graphene flakes, improving charge transmission through the film when calcined at temperatures above 300 °C [Other researchers have previously reported conductivities for graphene inks ranging from 1 to 105 S·cm−1 ,13,16,60−1) used in the ink formulation. Our inks were printed without any supplementary additives to regulate printability on the PET substrate and employed a moderate drying temperature of 40 °C, achieving good conductivity in the range of 1–4.5 S·cm−1. Our inks are suitable for flexible substrates in printed and flexible electronic fabrication, and their simple and cost-effective preparation stages make them ideal for large-scale manufacturing.In contrast, our inks surpass these earlier graphene inks due to the simplicity of our technique and the low dispersant concentrations (0.1–1.5 mg·mL2 structure (or graphitization degree), which measures the intensity ratio between D and G peaks (ID/IG ratio). −1 (D band), 1574 cm−1 (G band), and 2666 cm−1 (2D band). The displayed spectra show the median representations of Raman spectra collected at ten different locations on each sample. The raw graphite Raman spectrum exhibits an ID/IG ratio of 0.12, indicating the feature of well-crystallized bulk graphite. Exfoliation results in a minor increase in the D band, leading to a slight rise in ID/IG ratios (0.23–0.28), consistent with the values found for graphene inks (ID/IG ≈ 0.17–0.45) [The electrical properties of printed graphene structures are primarily determined by the quality of the materials and the interconnectivity between flakes ,18,65. Ratios 0.2–0.28, co17–0.45) ,16,60. T2 structure induced by dispersants.The bandgap and valence band measurements were performed to assess the quality of the graphene π-conjugated system in the inks, as shown in −2) [The flake interconnectivity and the wettability of the inks significantly influence the electrical conductivity of the graphene films. The interaction between the substrate and the graphene inks is governed by the match between the inks’ surface tension and the surface energy of the PET substrate (≈45 mJ·m−2) ,71, whic−2) . The droThe interconnectivity of graphene flakes is crucial for promoting charge transport within graphene films and increasing electrical conductivity, and it works in collaboration with the properties of the individual flakes. The surface morphology of the graphene films produced on PET substrates was analyzed using SEM. −1), which can be related to the high percentage of nanofillers of <200 nm flake size (12.2%), a low dispersant-to-graphene ratio (5%), good quality (ID/IG ≈ 0.27), good wettability (θ ≈ 42°) on PET, and a smooth and uniform film on PET.The DLS analysis revealed a high percentage (12.2%) of GTr flakes < 200 nm, which could enhance the electrical conductivity of the graphene films. Small flakes can fill in the gaps in the network structures, increasing the flake interconnectivity and the uniformity and density of the printed films. This is because they act as a bridge between graphene flakes by providing network frames and π-π interactions with the graphene flakes, creating additional charge transport pathways within the film. Overall, GTr has superior electrical conductivity , and after opening the chamber’s lid to expose the graphene sensor to the air again (Air 2 and Air 4).The investigation of the conduction process in the dry-solid state involved exposing printed graphene sensors  to N2, H2), indicating that there is no charge transfer from graphene to nitrogen , the sensors  have an initial resistance of 200–300 kΩ. However, the graphene sensors’ Nyquist plot showed no change after being exposed to the inert gas (Nnitrogen A–C. Lated sensor A and GTwd sensor C exhibit for GTr B expande3). It was anticipated that NH3 molecules would donate electrons to graphene flakes, increasing the matrix electron density and minimizing resistance. However, the sensors’ response can be explained by forming acidic NH4+ ions via dissociating of NH3•H2O [4+ ions can alter the exterior conduction properties of graphene interfaces [Interestingly, the graphene sensors showed an unexpected sensing response when exposed to the basic and electron-donating gas , resulting in electrical activation towards contemporary gases.In contrast, the GTr-based sensor B and GTwd sensor A expande0 ratio increase of 5% against bending angles up to 90°  and printed on PET substrates using an AJP without additional additives for printability. The drying temperature was kept moderate (40 °C), and the resulting inks demonstrated good conductivity (1–4.5 S·cm−1) suitable for chemiresistive sensor development. The study revealed that the dispersant used in the inks significantly influenced the graphene concentration achieved in the dispersion, the flake size distribution, number of graphene layers per flake, and the dispersant-to-graphene ratio, which in turn affected the inks’ wettability and smoothness on the substrate.This study developed practical water-based graphene inks. The inks were formulated with low dispersant concentrations (0.1–1.5 mg·mL−1) and mechanical flexibility. The results suggest that GTr is suitable for fabricating chemiresistive sensors for IoT healthcare and environmental applications due to its appealing properties and non-toxic ingredients.Triton X-100 was found to be the most effective dispersant for formulating the graphene ink (GTr) due to its ability to produce stable aqueous ink with low-defect few-layer graphene, high production yield efficiency, the highest percentage of graphene flakes < 200 nm, good printability, and quality of printed films, as well as good electrical conductivity (4.5 S·cm


In 1963, the American Academy of Orthopaedic Surgeons administered the Orthopaedic In-Training Examination (OITE), the first and longest running yearly medical specialty examination. There have been no recent studies to evaluate the content of the musculoskeletal trauma section of the OITE.We analyzed all questions that were classified by the American Academy of Orthopaedic Surgeons as musculoskeletal trauma from 2012 to 2019. We recorded the number of musculoskeletal trauma questions in each examination, the topics and imaging modalities tested, the references cited, and the taxonomy classification of each question. We extrapolated from a similar musculoskeletal trauma study published in 2011 to create the previous examination cohort for comparison.P < 0.001 and P = 0.02, respectively). In the current cohort, T3 questions were tested significantly more frequently than previous examinations (P = 0.001). Previous examinations had significantly more questions without an image . In current versions of the examination, radiographs are tested significantly more frequently than other imaging modalities (P < 0.001).For the current cohort, the average number of musculoskeletal trauma questions was 43.5 questions per examination (18.4%). The most frequently tested topics were proximal tibia fractures, pediatric trauma, hip fractures, and diaphyseal femur fractures, respectively. In previous examinations, questions from T1 and 2 were tested significantly more frequently compared with the current examinations (The musculoskeletal trauma section of the OITE has evolved. To improve and focus study efforts, residents may use this study as a guide when preparing for the examination. J. Vernon Luck, in 1960.2 The goals of the examination were to provide an examination that will permit the chiefs of training programs to evaluate the quality, scope, and comprehensiveness of their educational systems; to provide information to the residents who take the examination as to their performance in relation to their peer groups; to provide an instrument which may be used as a valuable education aid; and to investigate new methods of testing in education.2 The original examination consisted of 150 multiple choice questions while modern versions of the examination contain 275 multiple choice questions in 12 categories: foot and ankle, hand, orthopaedic science, hip and knee reconstruction, orthopaedic diseases, spine, pediatric orthopaedics, medical-related issues, sports medicine, musculoskeletal trauma, rehabilitation, and shoulder and elbow.2 Historically, the examination was administered on paper; however in 2009, the examination became computer-based.3 Multiple studies have demonstrated that resident OITE performance correlates with success on the (American Board of Orthopedic Surgery) Part I examination.3456In 1963, the American Academy of Orthopaedic Surgeons (AAOS) administered the Orthopaedic In-Training Examination (OITE), the first and longest running yearly medical specialty examination.7891011121314 OITE content undergoes frequent modifications to adhere to the advancing field of orthopaedics, and recent studies have been conducted to determine whether subspecialty content in the OITE changes over time; however, this has not been done for the musculoskeletal trauma section.16 Our goal for this study was to analyze OITE musculoskeletal trauma questions from 2012 to 2019 and compare them with the results reported by Cross et al and Lackey et al from 2011.With the goal of improving resident performance in the OITE, multiple studies have detailed OITE subspecialty-specific content.17 We recorded the number of musculoskeletal trauma questions in each examination, the topics and imaging modalities tested, the references cited, and the taxonomy classification of each question based on previously published studies.19 The taxonomic classifications were knowledge (taxonomy I), comprehension (taxonomy 2), and application (taxonomy 3). Taxonomy I questions require recall of facts; taxonomy 2 questions require the interpretation of information and images to make a diagnosis; and taxonomy 3 questions represent the highest levels of cognitive requirement and closely simulate the higher cognitive processes used in practice as the test taker is required to formulate a treatment plan.13We analyzed all questions that were classified by the AAOS as musculoskeletal trauma from 2012 to 2019. From 2012 to 2016, electronic versions of the examination with answers and explanations were available for download. From 2017 onward, the examinations with answers and explanations could only be accessed through ResStudy offered by the AAOS.14 Descriptive statistics were used to evaluate the data, and a two-sample Student t-test was used to analyze the data between two groups. Analyses were conducted using Minitab (Minitab), and significance was set at P = 0.05. No outside sources of funding were used.The results were then compared with the data of Cross et al and Lackey et al, which will be referred to as the previous examinations or the previous cohort.For the current cohort, the average number of musculoskeletal trauma questions was 43.5 questions per examination 18.4%) (range 31 to 52 questions)  (Table P = 0.001)  questions were the most frequently tested, followed by diagnosis and interpretation (T2) and treatment and decision-making (T3) questions, respectively. In the current examination cohort, T3 questions were the most frequently tested, followed by T1 and 2 questions, respectively. In previous examinations, questions from T1 and 2 were tested significantly more frequently compared with the current examinations . The Journal of Orthopedic Trauma was cited significantly more frequently than The Journal of Bone and Joint Surgery and The Journal of the Academy Orthopaedic Surgeons . The Orthopaedic Knowledge Trauma Update was the most cited textbook in the current cohort while Rockwood and Green's Fractures in Adults was the most cited textbook in the previous cohort (Table P = 0.18). In the current cohort, The Journal of Orthopaedic Trauma was cited significantly more frequently than all textbook citations combined (21.3 citations per year versus 9.5 citations per year P = 0.002).ns Table . The jourt Table . No signP < 0.001). Current examinations offer more groups of imaging combinations than previous examinations (10 versus 3), and the current cohort had significantly more questions with an associated image than the previous cohort . In current versions of the examination, radiographs are tested significantly more frequently than other imaging modalities (P < 0.001). No significant relationships were found when comparing specific imaging modalities  of the questions in recent versions of the examination focus on treatment and decision making, representing the highest levels of cognitive requirement and closely simulate the higher cognitive processes used in practice.13 Other OITE subspecialty analyses over a similar period as the current examination cohort report a shift toward decision-making and evaluation questions as we did.20 When preparing for the examination, residents should focus their efforts on how to apply their knowledge in patient care revolving around treatment and decision making.Although the quantity of musculoskeletal trauma questions was similar over the years, their content was not. Previous examinations focused on simpler questions revolving around recall and diagnosis, with a minority dedicated to treatment and decision making. Other OITE subspecialty analyses over a similar period as the previous examination cohort reported recall-focused questions to be the most prevalent as well.21 Previous examinations relied on questions that did not require the interpretation of imaging while recent versions of the examination had significantly more questions that required the interpretation of at least one image, comprising nearly half of the questions (49.3%). Newer versions of the examination also had more combinations of different imaging modalities as well. Schulz et al16 reported similar findings as well when analyzing the oncology section.Imaging was included on the OITE in 1968.The Journal of Orthopaedic Trauma, The Journal of Bone and Joint Surgery, and The Journal of the Academy of Orthopaedic Surgeons. The Journal of Orthopedic Trauma was cited markedly more frequently than any other journal in the musculoskeletal trauma section. Although the authors of this study think that textbooks are a valuable learning resource for residents, they should choose either Skeletal Trauma  or Rockwood and Green's Fractures in Adults  as a resource, but not both.14 While preparing for the musculoskeletal portion of the OITE, residents must keep in mind that The Journal of Orthopedic Trauma alone was cited markedly more frequently than all textbooks combined in the current cohort. Given that the average age of citation is from 2.8 to 3.2 years, residents would be best served by reviewing articles from this range when preparing for the examination.Many journals include articles on musculoskeletal trauma, but when studying for the OITE, residents should focus their efforts on 14 All OITE examinations, except for one, in the previously referenced studies were paper-based. Given that modern iterations of the examination are computer-based, our analysis becomes critical. We have demonstrated several differences between examinations that were likely facilitated by using a computer-based examination such as more questions requiring the interpretation of images and more combinations of imaging modalities. In addition, we have included an 8-year period, including the most recent OITE, while the other studies included a 5-year period and did not include the most recent OITE examination at the time of publication.14 With a longer study period, we offer comprehensive data and can more accurately describe the evolution of the examination. Another strength of our study is that we include the longest consecutive period when analyzing a subspecialty of the OITE.There are a few differences of our study when compared with the studies by Cross et al and Lackey et al. An important distinction between our analyses is the OITE became computer-based in 2009.19A potential limitation of this study is that the periods of our study and the previously referenced studies are discontinuous. Although we may not be able to determine the true nature of the evolution of the examination, an 8-year period is the highest reported in the literature. Another potential limitation is that none of the authors of the current study collaborated on the studies by Lackey et al and Cross et al, although we attempted to follow their methodologies as closely as possible. In addition, because question types and taxonomic levels were determined by a single institution, there is a potential for bias, although we used a system that is widely used.The Journal of Orthopaedic Trauma and should only use one textbook as a resource. We think that implementing these strategies will lead to a better performance in the musculoskeletal trauma section and the OITE as a whole.The musculoskeletal trauma section of the OITE has evolved. To improve and focus study efforts, residents should concentrate on how to apply their knowledge in the treatment of musculoskeletal injuries, using Table


The response spectral range covers 400–1800 nm; the responsivity peak is 106 A W−1; and the peak detection rate and peak response speed reach 1014 Jones and 250 µs, respectively. In addition, the regulation of positive and negative photocurrents at a gate voltage is characterized and the ionization process in impurities of the designed phototransistor at a low temperature is analyzed. Tunable bidirectional response provides a new degree of freedom for phototransistors' signal resolution. The analysis of the dynamic change process of impurity energy level is conducted to improve the device's performance. From the perspective of manufacturing process, the ultrathin phototransistor (20–30 nm) is compatible with functional metasurface to realize wavelength or polarization selection, making it possible to achieve large‐scale production of integrated spectrometer or polarization imaging sensor by nanoimprinting process.Graphene is a promising candidate for the next‐generation infrared array image sensors at room temperature due to its high mobility, tunable energy band, wide band absorption, and compatibility with complementary metal oxide semiconductor process. However, it is difficult to simultaneously obtain ultrafast response time and ultrahigh responsivity, which limits the further improvement of graphene photoconductive devices. Here, a novel graphene/C 60/Bi2Te3/C60/graphene vertical heterojunction phototransistor is proposed. The transport process for photogenerated charge and local field mechanism are discussed in detail by analyzing the photoelectric performance of the device at low temperatures and different gate voltages. The device not only shows excellent photoelectric detection performance, but also exhibits substantive possibility to achieve large‐scale integrated array imaging sensors.Here, a novel graphene/C Since Xia et al. prepared the first graphene phototransistor in 2009, graphene has been used in hybrid systems with various materials or even physical local fields to achieve photoelectric detection. For example, metasurfaces, quantum dots (QDs), nanowires, bulk materials, transition metal dichalcogenide materials, perovskite materials, and various organic substances have been combined with graphene to achieve a high performance photoelectric detection. These works have extensively promoted the research progress of graphene in the field of photoelectric detection. However, large‐scale array imaging is still a considerable challenge due to the engineering bottlenecks and theoretical limitations. To name a few, clean transfer of 2D materials and uniform growth of QDs/nanowires are the primary technical bottlenecks to achieve a homogeneous preparation of the array unit. Meanwhile, a high photoconductive gain is usually at the cost of sacrificing the response time due to the limitation of the defect state. Therefore, it is urgent to find a technical scheme that can realize the large‐scale uniform preparation of optoelectronic imaging devices with graphene and 2D materials.As a representative of 2D materials, graphene is an important scientific research object due to its characteristics of high mobility, wide band absorption, adjustable energy band, etc.5, 660/bismuth telluride (Bi2Te3)/C60/graphene composite film phototransistor, which shows an excellent photoelectric response and strong technical and theoretical potentials for integrated photoelectric detection based on graphene. In the horizontal direction, graphene creates efficient and controllable conductive channels. In the vertical direction, the covalent contact of graphene/C60 forms a charge transport interface to the transmission and separation of the photogenerated charges. The intermediate layer Bi2Te3 provides efficient light absorption in the near‐infrared band, broadening the response band of the device. At room temperature, this graphene/C60/Bi2Te3/C60/graphene phototransistor shows an ultrahigh peak responsivity (3 × 106 A W−1), fast response (250 µs), and response band covering 400–1800 nm. Moreover, the device exhibits positive and negative photocurrent responses under different gate voltages, which result from the interaction between photogenerated electrons and dark electrons in the graphene channel. The graphene/C60/Bi2Te3/C60/graphene phototransistor not only presents a tremendous photoresponse performance but also shows excellent potential in array applications. The composite film can be combined with the functional metasurfaces to form a single detector with polarization or wavelength selectivity, which makes it possible to realize spectrum detection and polarization imaging through array detector integration. Ultrathin thickness (30 nm) makes it possible to achieve a large‐scale production of integrated spectrometers or polarization imaging sensors by the nanoimprinting process.Herein, we propose a graphene/C charges.33 The2Figure60 thin film was deposited by vacuum thermal evaporation at an evaporation temperature of 420 °C with a substrate temperature of 150 °C  was subsequently deposited on C60  and graphene was fabricated onto Bi2Te3 by the same process. Finally, the film was patterned by photolithography and etching process to complete the device preparation. Figure 60/Bi2Te3/C60/graphene film.C Figure , a layer0 Figure . After tFigure60/Bi2Te3 interface and the localized energy levels in the bandgap caused by impurities and defects. As shown in Figure 60. As a result, the photogenerated electrons in C60 enter the P‐type graphene channel forming a negative photocurrent response with the visible light incident, as shown in Figure 60 cannot be excited by the infrared photons of low energy due to band limitation. The Bi2Te3 film with narrow bandgap will respond to the infrared light and generated electron–hole pairs, but the barrier at the interface of C60 and Bi2Te3 limits electrons to enter C60. Since the valence band of Bi2Te3 is close to the impurity energy level in C60, it provides a channel for photogenerated hole injection into P‐type graphene, and generates a positive photocurrent, as shown in Figure 2Te3 thin film through the ellipsometer, as shown in Figure 2Te3 and the absorption spectrum of the composite film was obtained through finite difference time domain (FDTD) simulations, as illustrated in Figure 2Te3 is about 20 nm, which determines the structure in experiment. Figure 2Te3 film, the characteristic peak for Bi2Te3 can be clearly seen with different incident powers. Figure 60, and graphene/C60/Bi2Te3. The characteristic peaks of different materials appear subsequently, which proves the good quality of each film. The experimental absorption spectra of composite film in 400–1800 nm wave band are shown in Figure As shown in 60/Bi2Te3/C60/graphene phototransistor. Figure5 A W−1) at room temperature at 850 nm with a 0.3 µw incident light power. In addition, the phototransistor not only shows a high responsivity but also displays a fast speed response. As clearly presented in Figure I–V curve of the device is not a straight line, because the contact interface in the vertical direction forms a built‐in electric field, as shown in Figure I–V curve of the infrared region is shown in Figure Next, we systematically measure the photoelectric performance of graphene/CFigureD*) and photocurrent of the device with different wavelengths and incident light powers. The relationship between photocurrent and incident optical power is Iph ∝ Pα, where α is the power factor of the device ranging from 0 to 1. The responsivity of the device is R = Iph/P, thus we can obtain the relationship R ∝ Pα)− is just at the zero point. If a positive gate voltage is applied to the device, its Fermi level will move to the valence band forming P doping and its VDirac will also move to the positive axis. If the gate voltage becomes negative, its Fermi level would move to the conduction band, forming N doping, and its VDirac will move to the negative axis. Figure VDirac of the device is on the positive axis, demonstrating that the graphene channel is P‐doped, and the dominant carriers are holes. Therefore, the doping type of graphene can be easily judged by its Ig–Vg curve (transfer characteristic curve). After impurities and defects form localized energy levels in the bandgap, the conductivity strongly changes with temperature and its internal impurity concentration because the carrier concentration and Fermi level are determined by temperature and impurity concentration. With the temperature decreasing from −50 to −190 °C, the VDirac transfers from 25 to 40 V regardless of the light excitation, as shown in Figure We take silicon oxide as the dielectric layer of gate, and apply the gate voltage to obtain the transfer characteristic curve, as shown in VDirac, because the concentration of photoexcited charges from the impurity level was changed. Interestingly, the varying range of VDirac caused by different incident lights reduces as the temperature decreases. Keeping the incident light conditions unchanged, the varying range of VDirac caused by photoexcitation at −50 °C is significantly greater than the one at −190 °C. The reason can be attributed to the ionization degree of impurities, which is reduced with the decrease of temperature. It indicates that the position of the impurity energy level is close to the Fermi energy level as the temperature decreases, following Formulas   after four months of the device's fabrication. To show the uniformity of the devices, we prepared 3 × 8 array graphene–C60–Bi2Te3–C60–graphene heterojunction phototransistors, and measured the dark‐current value and photocurrent value at a bias voltage 0.05 V (with 680 nm light), as shown in Figure Furthermore, to show the sensitivity and repeatability of the device, we give the photocurrent of the device when the minimum optical power is incident. As shown in Figure 36 A W−1@0.25 ms). The graphene/C60/Bi2Te3/C60/graphene vertical heterojunction is placed on the source and drain electrodes forming a photoconductive transistor and patterned to micrometer size by DRIE (Deep Reactive Ion Etching) and photolithograph. At room temperature, the response band of the single device covers 400–1800 nm. The phototransistor not only exhibits a sensitive and fast response but also presents an adjustable bidirectional response, and we clearly explain the response mechanism. The thickness of the composite film is about 30 nm, which can realize a large area homogenization preparation and is compatible with planar lithography, etching, and nanoimprinting processes. Therefore, the phototransistor based on the composite film can be fabricated into large area array and combined with multifunctional nanostructures through nanofabrication methods like electron beam lithography and nanoimprinting, forming on‐chip spectrometer, polarization spectral imaging, and other functional array devices.In conclusion, we report a phototransistor with an ultrahigh responsivity and fast response time (3 × 104−3 Pa).Photoresponse characteristics of the heterojunction phototransistor were measured by a PDA source meter analyzer and a supercontinuum laser source from 400 to 2400 nm . All electrical tests were carried out under vacuum  with a 532 nm laser. The optical absorption spectra were measured by Lambda750 spectrophotometer (PerkinElmer).R = Iph/P; NEP: NEP = P/(Iph/Inoise); D*: (AdΔf)1/2Iph/Inoise/P.The photocurrent was collected by taking the average of ten switching cycles within error 5%. The intensity of incident light spot was calculated according to uniform illumination when the size of light spot was less than 40 µm. The noise current conformed to the normal distribution and was read out by the noise analysis module in the semiconductor analyzer PDA. The numerical calculation was in strict accordance with the standard formula of photodetector. Responsivity: Graphs were prepared in Origin 9.0.The authors declare no conflict of interest.Supporting InformationClick here for additional data file.