The monolayer graphene feedthrough exhibits a minor resistance increase from 22.5 Ω to 31 Ω after anodic bonding, showing good electrical conductance. The pressure of the vacuum chamber is estimated to be 185 Pa by measuring the breakdown voltage. Such a vacuum is found to maintain for more than 50 days without obvious degradation, implying a high sealing performance with a leak rate of less than 1.02 × 10−16 Pa·m3/s.On-chip microscale vacuum chambers with high sealing performance and electrical feedthroughs are highly desired for microscale vacuum electronic devices and other MEMS devices. In this paper, we report an on-chip microscale vacuum chamber which achieves a high sealing performance by using monolayer graphene as lateral electrical feedthrough. A vacuum chamber with the dimensions of π × 2 mm × 2 mm × 0.5 mm is fabricated by anodically bonding a glass chip with a through-hole between two Si chips in a vacuum, after monolayer graphene electrodes have been transferred to the surface of one of the Si chips. Benefiting from the atomic thickness of monolayer graphene, the leak rate of Si–glass bonding interface with a monolayer graphene feedthrough is measured at less than 2 × 10 Micro-Electro-Mechanical System (MEMS) devices have attracted much attention due to their compact size and low cost. Many MEMS devices, such as gyroscopes , RF devi−8 Pa·m3/s [Electrical feedthroughs in MEMS devices can be summarized as being in two classes: vertical feedthrough and lateral feedthrough. Vertical feedthrough usually achieves a conducting channel by drilling a via-hole through a glass  or silic Pa·m3/s . To ensu Pa·m3/s . An easyGraphene, a one-atom-thick nanomaterial, has been of wide interest in recent years . Its monA sandwich-like on-chip microscale vacuum chamber was constructed by anodic bonding. The schematic structure of the device and its fabrication processes are shown in 2 (500 µm/300 nm) chip was first treated by reactive ion etching (RIE) with O2 plasma for hydrophilicity [2 chip, as shown in 2 chip ) with a semiconductor characterization system (Keithley 4200). It can be seen from the image that both of the I–V curves have a good linear relationship. The resistance of the graphene electrode is 22.5 Ω before bonding and 31 Ω after. Such a resistance is better than many other devices using lateral [As shown in  lateral  or verti lateral ,19,20, wOn-chip microscale vacuum chambers often require high sealing performance, so airtightness of bonding interface is a very important issue. The bonding interface’s airtightness with respect to the two-layer device shown in 2–glass bonding interface  and the pressure P (Pa) of the intervening gas. For large gaps (d > 100 μm [BV(V) asA and B are two fitting parameters, γ is the second Townsend coefficient which describes the mean number of generated secondary electrons per ion. Parameters A = 10.95 Pa−1m−1, B = 273.78 VPa−1m−1 in air are well determined by ref [Pd. As Pd increases, BV first decreases to a minimum at several hundred Volts and then increases again. At low pressures, few collisions require high probability of ionization, so a higher electric field is needed. At high pressures, short mean free path makes it difficult for electrons to accumulate enough energy to reach ionization energy, which also requires a higher electric field, resulting in a minimum in Paschen’s law.Paschen’s law  describe> 100 μm ), the “Pd by ref . EquatioBV was 2192.5 V. Taking P = 1.01 × 105 Pa, d = 0.5 mm, A = 10.95 Pa−1m−1, B = 273.78 VPa−1m−1, VB = 2192.5 V, the second Townsend coefficient is calculated as 0.57 according to Equation (1). Therefore, the parameter values of Paschen’s law are A = 10.95 Pa−1m−1, B = 273.78 VPa−1m−1, γ = 0.57, which will next be used to estimate the vacuum level of a three-layer device with a microscale vacuum chamber.We first prepared a three-layer device by stacking Si–glass–Si chips in the air without bonding, with the sizes of the glass spacer and the Si chips the same as those described above. The gap between electrodes in our configuration is 0.5 mm, which is well above the microscale boundary where Paschen’s law may deviate due to field emission . The meaA simple apparatus was developed to test the breakdown voltage of our device, as shown in 6 s (50 days) within the allowable range of errors. The breakdown voltage corresponds to a pressure of the chamber of 185 Pa according to Paschen’s law with the above determined parameters. Considering the flow resistance caused by our bonding apparatus and the residual gas generated in the bonding process and released from inner surfaces, such a vacuum level is reasonable [PV in the chamber with time is obtained, as shown in PV (difference between maximum and minimum) is no more than 4.6 × 10−10 Pa·m3, the leak rate is estimated to be under 1.02 × 10−16 Pa·m3/s. Although the vacuum degree of the microscale vacuum chamber is not good enough for some high-vacuum applications, the result shows that using monolayer graphene as lateral feedthrough could maintain a vacuum of 185 Pa and a leak rate of less than 1.02 × 10−16 Pa·m3/s for about two months, realizing a high sealing performance. In the future, a high-vacuum microscale chamber using a graphene electrode as lateral feedthrough could be realized by improving the bonding process to further improve the initial vacuum degree of the chamber.Finally, a microscale vacuum chamber device using a graphene electrode as lateral feedthrough with a high sealing performance was fabricated shown in g. The brasonable  and can asonable  to the c2–glass bonding interface with a monolayer graphene feedthrough was measured to reach the measurement limit of the detector, namely less than 2 × 10−11 Pa·m3/s. For a bonded three-layer device with a microscale chamber, the pressure of the chamber was estimated as 185 Pa and had been maintained for more than 50 days. During this period, the leak rate was less than 1.02 × 10−16 Pa·m3/s, achieving a high sealing performance. In summary, the on-chip microscale vacuum chamber using graphene as lateral feedthrough is a reliable, simple and promising electrical feedthrough solution for vacuum electronic devices and other MEMS devices.In this paper, an on-chip microscale vacuum chamber with dimensions of π × 2 mm × 2 mm × 0.5 mm was fabricated, where a graphene electrode was innovatively used as a lateral electrical feedthrough. The monolayer graphene feedthrough shows a slight increase in resistance from 22.5 Ω to 31 Ω after anodic bonding, showing good electrical conductance. Benefiting from the atomic thickness of monolayer graphene, the leak resulting from the height difference between the electrode and the substrate surface was reduced, which effectively improved the sealing performance. The leak rate of Si/SiO


Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease of unknown origin that usually results in death from secondary respiratory failure within 2–5 years of diagnosis. Recent studies have identified key roles of cytokine and growth factor pathways in the pathogenesis of IPF. Although there have been numerous clinical trials of drugs investigating their efficacy in the treatment of IPF, only Pirfenidone and Nintedanib have been approved by the FDA. However, they have some major limitations, such as insufficient efficacy, undesired side effects and poor pharmacokinetic properties. To give more insights into the discovery of potential targets for the treatment of IPF, this review provides an overview of cytokines, growth factors and their signaling pathways in IPF, which have important implications for fully exploiting the therapeutic potential of targeting cytokine and growth factor pathways. Advances in the field of cytokine and growth factor pathways will help slow disease progression, prolong life, and improve the quality of life for IPF patients in the future. Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrotic interstitial lung disease of unknown etiology that usually results in death from secondary respiratory failure within 2–5 years of diagnosis . It is avia multiple signaling pathways-  are damaged, and the continuity of the basement membrane is interrupted due to a variety of external stimuli, such as radiation, the microbiome, allergens, environmental particles, autoimmunity, antineoplastic drugs , and SARvia the epithelial-to-myofibroblasts transition  and differentiation of fibroblasts into myofibroblasts occur, promoting the expansion of myofibroblast population which is the main source of extracellular matrix (ECM) . Notablyansition . In contansition . It has ansition . Due to ansition , causingansition . TherefoA large number of cytokines and their signaling pathways are directly involved in the accumulation of fibroblasts in lung fibrosis foci . FibroblGrowth factors and cytokines are an integral part of the fibrotic microenvironment, which leads to differences in the phenotype of immune cells in the alveoli between patients with pulmonary fibrosis and healthy individuals. Th1/Th2 imbalance and M1-M2 polarization are hallmarks of pulmonary fibrosis. Th2 polarization is characterized by increased secretion of IL-4 and IL-13 and decreased secretion of IFN-γ. M2 polarization can be induced by the microenvironment shaped by Th2 polarization and promotes pulmonary fibrosis through the production of TGF-β, CCL18, chitinase 3-like 1 (CHI3L1), MMPs, and activation of the Wnt/β-catenin pathway . Th17 ceTransforming growth factor-β (TGF-β) is a potent profibrogenic cytokine that plays a central role in the development of pulmonary fibrosis by promoting fibroblast proliferation and phenotype modulation, stimulating the deposition of ECM, and participating in crosstalk with other cytokines and signaling pathways .i) In the endoplasmic reticulum (ER), TGF-β precursors are assembled into dimers wrapped with latency-associated peptides (LAPs). TGF-β-LAPs bind to latent TGF-β binding protein (LTBP) and undergo intracellular proteolytic cleavage by the endopeptidase furin. Then, TGF-β-LAP-LTBPs are secreted into the extracellular medium and eventually bind to ECM  through LTBP. At this time, latent TGF-β cannot exert its biological function .ii) Latent TGF-β is activated under special conditions [e.g., plasmin , thromboiii) TBR2 can phosphorylate TGF-β receptor 1 (TBR1) and activate the downstream classical and non-classical pathways.iv) In classical pathways, Smad2/Smad3 activated by TBR1 binds to Smad4 to form Smad2/Smad3/Smad4, which enter the nucleus and participate in regulating transcription factors . Classicv) Some transcription factors of fibroblasts, alveolar epithelial cells, endothelial cells, and Th cells are changed, causing the phenotypic transformation of cells involved in pulmonary fibrosis, which eventually leads to the differentiation of myofibroblasts, the deposition of ECM, the abnormal function of AT II, and an imbalance of immune cells in IPF.The activation of TGF-β pathway includes five steps, including i) synthesis of TGF-β, ii) activation of latent TGF-β, iii) interaction between TGF-β and TGF-β receptor (TBR), iv) activation of classical and non-classical pathways, and v) regulation of nuclear transcription factors and cell phenotypes. A brief introduction to the TGF-β pathway is as follows and shown in The TGF-β pathway is interrelated with the Wnt/β-catenin pathway, PI3K/Akt pathway, and pathways of other growth factors . FurtherStrategies for the treatment of IPF by targeting the TGF-β pathway include blocking TGF-β synthesis, preventing activation of latent TGF-β, neutralizing TGF-β ligands/receptors, and blocking canonical and non-canonical pathways . These svia FAK phosphorylation, ultimately leading to fibroblast phenotype reprogramming.Integrins mediate the mechanotransduction positive feedback to ECM stiffness in a TGF-β-dependent or TGF-β-independent manner, which is an important therapeutic target. TGF-β-dependent fibrosis is activated by integrins releasing TGF-β through tensile forces generated by actin-cytoskeleton interactions. In the TGF-β-independent pathway, after binding specific ECM ligands to the ectodomain of integrins, integrins bind to the cytoskeleton and various signaling proteins through their cytoplasmic tails, translating the mechanical force of cytoskeleton contraction and ECM stiffness into biochemical signals. Then, F-actin activates the downstream Rho/ROCK-YAP/TAZ signaling pathway There are corresponding preclinical candidate drugs for IPF that target different steps of the TGF-β pathways, including the synthesis, receptor binding, and downstream signal transduction , but no As described above, cytokines, growth factors, and related signaling pathways are intensively involved in the pathogenesis of IPF. Therefore, they might be promising targets to develop novel treatment options for IPF. In this section, we describe the roles of growth factors, chemokines, interleukins, lipid pro-inflammatory mediators, and their signaling pathways in IPF. Many drugs targeting these pathways are in development, and we summarize those that have entered clinical trials to treat patients with IPF. In recent years, therapeutics targeting these pathways have shown many limitations in clinical trials. Therefore, we propose possible approaches to overcome these limitations, aiming to provide insights into the development of therapies with fewer side effects and better efficacy.Growth factors can participate in the development and progression of IPF in TGF-β-dependent or TGF-β-independent ways. These growth factors comprise platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), connective tissue growth factor (CTGF), and insulin-like growth factor (IGF). Due to the successful marketing of Nintedanib (an antagonist of PDGFR/VEGFR/FGFR), many studies have focused on growth factors and their corresponding receptors. However, there remains considerable controversy regarding the roles of many growth factors in promoting fibrosis and resisting fibrosis in IPF. One of the possible reasons for the controversy is that there are many subtypes of these growth factors and their receptors, and the functions of different subtypes differ. Although pharmacological analysis of these subtypes of growth factors is difficult, it is a vital step toward precise treatment and personalized treatment, which is of substantial significance. Next, we introduce the crucial growth factors PDGF, FGF, VEGF, EGF, and CTGF in detail.Platelet-derived growth factor (PDGF) is a key growth factor that stimulates the proliferation and migration of fibroblasts. In a mouse model of bleomycin-induced IPF, RT–PCR , PDGF an2+ influx and cytoskeleton rearrangement . An FGF can bind to multiple FGFRs. FGFs rely on heparan sulfate proteoglycan (HSPG) and Klotho-type coreceptors to improve their binding to FGFRs . After Fin vitro , FGF10 blocks the lipofibroblast-to-myofibroblast transformation induced by TGF-β1 and promotes the transformation from myofibroblasts to lipofibroblasts. In addition, the FGF10 paracrine signal was considered crucial to the differentiation of alveolar epithelial progenitor cells during development and the maintenance of AT II in a steady state , VEGFR2 (KDR or Flk1), and their coreceptors neuropilin-1 and neuropilin-2. Among them, VEGFR1 binds to circulating VEGF-α and reduces its bioavailability to VEGFR2. The coreceptors neuropilin-1 and neuropilin-2 assist in the signal transduction of VEGFR1 and VEGFR2. After binding to VEGFR2, VEGF-A165 can activate the downstream Akt pathway, Src signaling pathway, NCK and the p38 MAPK pathway, and integrin/FAK pathway . VEGF cain vitro experiments, VEGF-A165a has been proven to promote the proliferation of AT II and fibroblasts, increase the expansion of ECM, and play a role in promoting fibrosis, and VEGF-A165b could counteract this effect  belongs to the ErbB family receptor tyrosine kinases. EGFR has seven corresponding ligands: EGF, transforming growth factor-α (TGF-α), amphiregulin, betacellulin (BTC), epiregulin, epigen, and heparin-binding EGF-like growth factor (HB-EGF). After ligands bind to EGFR, the autophosphorylation of EGFR can activate the downstream MAPK, Akt, and JNK pathways and promote cell proliferation .in vivo, studies have found that collagen deposition decreases and lung morphology improves, which indirectly indicates that the ErbB family plays a role in fibrosis (The relationship between the ErbB family (HER) and IPF remains unclear and thus requires further research. After blocking HER fibrosis . In addifibrosis .CTGF, also known as CNN2, HCS24, or IGFBP8, belongs to the CNN family. CTGF can interact with a wide range of ECM components, but this also means that the biological action of CTGF is highly dependent on the local microenvironment. CTGF directly binds to other growth factors , which influence signal emission/transduction . CTGF caAs an auxiliary regulator of TGF-β in IPF in the local microenvironment, CTGF can participate in abnormal tissue repair processes, such as ECM generation and the mobilization of fibroblasts, by assisting TGF-β . There wChemokines are small molecule proteins with chemotactic effects on specific cells, and there are four conserved cysteine residues. According to the differences in cysteine residues, chemokines have been divided into four main subfamilies: CXC, CC, CX3C, and XC. Although the role of some chemokines in IPF remains unknown, many studies have demonstrated that chemokines can promote fibrosis or resist fibrosis. It has been reported that pulmonary fibrosis in animal models can be attenuated by knocking out genes encoding chemokines or neutralizing chemokines with antibodies [CCL2-CCR2 , CCL11-CChemokines play a crucial role in the pathological process of IPF . CXCL12-Interleukins are a class of cytokines generated by lymphocytes, monocytes, and other non-monocytes. In addition to affecting fibrosis by modulating the Th1/Th2 balance, many studies have shown that interleukins can also directly affect fibroblasts and epithelial cells . Thus, iHowever, clinical trials of IPF treatments targeting IL-4 and IL-13 have not gone well. Several drugs targeting IL-13 have entered clinical trials for IPF, but none of them have shown protective effects on lung function. Although clinical trials of IPF antibody drugs have mostly failed in phase II, there is still hope for interleukin therapy. Inhibition of IL-11 blocks TGF-β1, PDGF, FGF2, IL-13, OSM (Oncostatin M), and endothelin 1-mediated fibroblast activation .Notably, interleukin supplementation alone may not reverse the profibrotic phenotype of cells, and the regulation of cell–cell interactions or phenotypic transformation may be more promising. In addition, anti-inflammatory interleukins should be used with caution in clinical trials, and attention should be given to their side effects on patient immune function. In addition, rational design of interleukin dosage forms is very important because the concentration of the drug in the lungs can explain some of the differences in the study results.Various lipids and their metabolic derivatives play vital roles in IPF. Although glucocorticoids (PLA2 inhibitor) have not shown positive effects in the treatment of IPF in clinical trials, these findings do not indicate that all lipid metabolism pathways have no significance as therapeutic targets of IPF. In contrast, metabolomic studies on fibroblasts have received increasing attention in recent years.LT and PG are implicated in the pathogenesis of IPF. In arachidonic acid metabolic pathways, phospholipids produce arachidonic acid under the catalysis of phospholipase A2 (PLA2). Then, arachidonic acid produced leukotriene (LT) and prostaglandin (PG) under the catalysis of 5-lipoxygenase (5-LO) and cyclooxygenase (COX), respectively. Among them, PGF2a and LTs promote fibrosis, and PGE2 resists fibrosis . A phaseThe SPHK1/S1P/S1PR axis is involved in pulmonary fibrosis. In sphingolipid metabolism, sphingosine kinase 1 (SPHK1) phosphorylates sphingosine to produce sphingosine-1-phosphate (S1P). Then, the binding of S1P to the S1P receptor can lead to mitochondrial reactive oxygen species (mtROS) and promote YAP1 entry into cell nuclei, affecting the differentiation of myofibroblasts and matrix remodeling . Targetiin vivo, among which ATX/LPA/LPAR is the main pathway. Phosphatidylcholine (PC) generates LPC (lysophosphatidylcholine) under the action of phospholipase A1/phospholipase A2 (PLA1/PLA2), and LPC is hydrolyzed under the action of autotaxin (ATX)/lysoPLD to generate LPA. LPA exerts biological effects by binding to LPAR (The ATX/LPA/LPAR axis plays a potent role in pulmonary fibrosis. Lysophosphatidic acid (LPA) has been proven to activate G protein-mediated signal transduction pathways by binding to its receptors (LPAR1 and LPAR2), which leads to different reactions from lung cells, including the promotion of the apoptosis of epithelial cells, regulation of endothelial permeability, activation of αvβ6 integrin-mediated TGF-β signaling, secretion of IL-8, and recruitment and survival of fibroblasts . LPA can to LPAR . Drugs tvia phenotype modulation of fibroblasts and AECs  are receptor-type tyrosine kinases (RTKs), and their counterparts are non-receptor-type tyrosine kinases (non-RTKs) free in the cytoplasm. Src family kinases (SFKs) are a non-RTK family with eleven members, among which Src, Yes and Fyn are ubiquitously reported . RTK andand AECs .The combination of TGF-β and TBR can not only initiate the TGF-β/Smad signaling pathway but also indirectly participate in the differentiation of fibroblasts by activating Src/p38  and Fyn/via the Src/PI3K/Akt pathway  and its receptor ptch1 and then activates downstream pathways in a Gli transcription factor-dependent  or independent  manner. In the canonical pathway, the binding of Hh to ptch1 relieves the inhibitory effect of ptch1 on Smo. Then, Smo is transferred to the plasma membrane and participates in the regulation of genes in the nucleus by activating full-length Gli to become Gli1/2/3 (active form), thereby inducing AEC apoptosis, fibroblast differentiation, EMT, and M2 polarization . In the The Wnt signaling pathway is an important signaling pathway in response to postnatal injury and regeneration. Binding of Wnt3a to Frizzled (FZD), followed by β-catenin accumulation, induces AECs to release proinflammatory factors  and promotes fibroblast collagen synthesis. In addition, Wnt-inducible signaling protein-1 (WISP-1) is also involved in AEC reprogramming and proliferation . TGF-β pThe Notch pathway is a highly conserved signaling pathway that mediates short-range signaling in neighboring cells. The Notch ligand-expressing cell binds to the Notch receptor, causing the Notch intracellular domain (NICD) of the Notch receptor to break and enter the nucleus to lead to gene transcription. Lfng positively regulates this process, while Numb negatively regulates this process . Notch iIn recent years, research on the molecular mechanism of fibrosis has become increasingly in depth, and the JAK/STAT, PI3K/Akt/mTOR, MAPK, and Hippo-YAP/TAZ signaling cascades have received extensive attention . Drugs tCells respond to inflammatory factors rapidly through JAK/STAT signaling. After interleukins  and growth factors  bind to the corresponding receptors, they can activate and interact with the receptors. Receptor-coupled JAKs  phosphorylate STATs  . Homodimvia 4E-BP1  mainly consists of three downstream cascades, the JNK, p38 and ERK pathways. JNK/p38 is activated  cascade . JNK and cascade . MK2, do cascade . Growth  cascade . The ERKin vitro .via Rho/ROCK signaling and promote pulmonary fibrosis  on YAP/TAZ. After entering the nucleus, YAP/TAZ regulates AT I apoptosis and AT II exhaustion, fibroblast proliferation and ECM expansion . The mecfibrosis . Differefibrosis . Tank bifibrosis .Antifibrotic therapy provides survival benefit and protection against all-cause and respiratory-related hospitalization for IPF patients . FDA appPirfenidone is a pyridine compound approved for marketing in Japan in 2008. It was originally developed as an anti-inflammatory drug. Interestingly, studies in animal models demonstrated that it had the effect of resisting fibrosis of various organs, and it was later approved for IPF treatment. The anti-fibrotic mechanism of Pirfenidone has not been fully elucidated. Published studies indicated that it could inhibit fibrosis mainly by blocking TNF-α and TGF-β/Smad pathways .post hoc analysis of ASCEND and CAPACITY program suggested a clinically relevant benefit of Pirfenidone in IPF patients with more advanced lung function impairment  and a high daily dose . Although generally well tolerated, a minority of patients discontinued treatment due to gastrointestinal and skin-related adverse events. These side effects can be mitigated or prevented by taking it with/after meals, avoiding Sun exposure, wearing protective clothing, and using broad-spectrum sunscreens . In addiNintedanib is a small molecule tyrosinase inhibitor approved for marketing in 2014. Initially, researchers intended to screen drugs that selectively inhibit VEGFR-2 for anticancer treatment. However, in subsequent research, Nintedanib had good antifibrotic and anti-inflammatory effects and was approved for IPF treatment. Nintedanib mainly inhibits tyrosine kinase receptors, such as PDGFR, FGFR, and VEGFR, and non-receptor tyrosine kinases, such as Src and Flt-3 .The INPULSIS-1 and INPULSIS-2 programs demonstrated that Nintedanib could delay FVC decline and reduce the risk of disease progression . Howeverpost hoc analysis of INPULSIS program suggested that probable UIP with traction bronchiectasis in high-resolution CT might be sufficient for patients to benefit from Nintedanib, implying the importance of early antifibrotic therapy (The timing of antifibrotic therapy may influence the outcome of IPF treatment. A retrospective study indicated that patients who initiated Nintedanib immediately after IPF diagnosis might have reduced hospitalization risk and medical costs compared with those who start treatment later . A post  therapy .post hoc analyses of the INPULSIS and INSTAGE programs suggest that it has some effect in IPF patients with more severely impaired gas exchange (Although high-quality clinical trial data are currently lacking to directly demonstrate that Nintedanib is effective in end-stage IPF, the latest exchange .With the launch of Pirfenidone and Nintedanib in multiple countries, the number of IPF patients not receiving anti-fibrotic therapy will decrease in the future, and it will become increasingly difficult to observe the natural progression of IPF. For ethical reasons and feasibility of patient recruitment, more and more clinical trials of new drugs will use Pirfenidone and Nintedanib as controls. This sets a higher standard for the efficacy of new drugs. In addition, there will be a trend to combine new drugs with existing anti-fibrotic therapies in clinical trials, and whether they can bring additional benefits will be the determining factor. Furthermore, whether a single drug is sufficient to effectively delay the progression of IPF is an important pharmacoeconomic proposition. Since IPF is a rapidly progressive and irreversible disease, whether anti-fibrotic therapy is effective in different stages of IPF, especially in end-stage IPF and suspected IPF, also deserves further study. There are currently no high-quality clinical trials that directly demonstrate the efficacy of antifibrotic therapy in end-stage IPF. In addition, whether patients with suspected IPF on unbiopsied CT images without biopsy require prophylactic antifibrotic therapy remains to be further investigated.With the continuous exploration of the pathophysiological process of IPF and the continuous clarification of the cytokine and growth factor pathways, the targets of IPF treatment have also become diversified. Many targets and drugs developed based on them have entered clinical trials . AlthougComplications and comorbidities are of substantial significance to the disease progression and quality of life in IPF patients.Cough affects up to 80% of patients with IPF, is frequently disabling, and lacks effective therapy. A 24-week, double-blind, two-treatment, 24 patients enrolled, two-period crossover trial showed that thalidomide improved cough and respiratory quality of life in patients with IPF .Patients with IPF are also at risk of developing pulmonary hypertension as the underlying condition worsens . The BUIIncreased bacterial load and loss of microbial diversity have been reported in IPF , which aGastroesophageal reflux occurs in a high proportion of IPF patients , and chrResearch on the pathogenesis of IPF has made considerable progress. After years of preclinical research and clinical studies, the pathogenesis of IPF has changed from simple inflammation to abnormal epithelial-mesenchymal crosstalk and other pathogenic mechanisms. Based on the emerging pathological mechanism, many studies have systematically studied the key roles of cytokine and growth factor pathways in the pathogenesis of IPF. The approval of Pirfenidone and Nintedanib shows that therapy targeting these pathways is very promising. Although investigational drugs targeting some cytokines such as IFN-γ, TNF-α, and IL-13 have not shown satisfactory efficacy, the development of anti-IPF drugs targeting cytokine and growth factor pathways is still promising. Currently, there are numerous clinical trials investigating the efficacy of these drugs in the treatment of IPF and more drugs may be approved based on the results of these trials.Advances in the field of cytokine and growth factor pathways would help slow disease progression, prolong lives, and improve the quality of life of IPF patients in the future. Therefore, this review tried to provide an overview of cytokines, growth factors, and their signaling pathways in IPF. Furthermore, key information about emerging drugs targeting these pathways for IPF treatment in clinical trials is provided.Based on the findings of this review, the following points need to be considered in future studies to make strategies targeting these signaling pathways more promising for the treatment of IPF patients. Although upregulating or antagonizing certain cytokine or growth factor signaling pathways alone may not reverse differentiated cells, promoting fibrotic phenotype transition is more promising. Since cytokine and growth factor signaling pathways also play vital roles in other physiological and pathological processes, including damage repair, defense against infection, autoimmune disease, and antitumor immunity, long-term non-selective targeting of these pathways may lead to undesired side effects. Therefore, the identification of more specific targets and the development of drugs having high selectivity on them, the optimization of drug delivery to increase drug concentrations at the target site, and the identification of biomarkers to help select patients who might benefit more from drugs are all worth exploring. In addition, combination therapy with Pirfenidone and Nintedanib might bring better clinical benefits for IPF patients than single drug administration.One of the novelties of this review is giving an extensive description of the multiple roles of cytokine and growth factor pathways in pulmonary fibrosis, which provide new insights into therapeutic strategies for IPF. These pathways form a complex network in the pathological process of pulmonary fibrosis, and exploring the crosstalk between different signaling cascades may help discover more potential targets. Clinical trials are a critical stage that all approved drugs must go through. Some of the drugs in clinical trials for the treatment of IPF target cytokines and growth factors. Therefore, we summarize key information from these clinical trials and hope to give insights for the development of more effective drug.Although IPF is idiopathic by definition, it may become less mysterious with progress in the understanding of the pathogenesis of IPF. This review showed that the number of therapeutic targets from cytokine or growth factor signaling pathways and new targeted drugs entering clinical trials is increasing. These advances show that slowing disease progression, prolonging prognosis, and improving quality of life might be possible in the future for patients with IPF.In conclusion, cytokine and growth factor signaling pathways are indispensable in the pathogenesis of IPF, and this review hopes to provide theoretical support for the development of novel anti-pulmonary fibrosis drugs targeting cytokine and growth factor pathways.


We pattern the platinum film, after which a CVD graphene layer is grown at the interface between the SiO2 and the Pt. After removing the Pt, Raman spectroscopy demonstrates the local growth of monolayer graphene on SiO2. By tuning the CVD process, we were able to fully cover 4-inch oxidized silicon wafers with transfer-free monolayer graphene, a result that is not easily obtained using other methods. By adding Ta structures, local graphene growth on SiO2 is selectively blocked, allowing the controlled graphene growth on areas selected by mask design.Since the transfer process of graphene from a dedicated growth substrate to another substrate is prone to induce defects and contamination and can increase costs, there is a large interest in methods for growing graphene directly on silicon wafers. Here, we demonstrate the direct CVD growth of graphene on a SiO Since the discovery of graphene in 2004, it has become increasingly clear that the exceptional electronic, optical and mechanical properties of this material can lead to revolutionary new devices. Next generation transistors, RF circuits, optoelectronic devices and sensors with huge performance merits might become feasible. For producing such devices in high-volume and creating hybrid circuits comprising both graphene and silicon devices, it is highly desirable to integrate them with advanced complementary metal-oxide-semiconductor (CMOS) technology.To realize this integration , productIn modern CVD processes, graphene is grown on foils, or thin films of transition metals, the most common of which are: Cu, Ni, Mo and Pt. For CMOS integration, the graphene needs to be transferred from these foils onto a silicon wafer. There are several ways to achieve this , but theThis transfer-based CVD graphene integration route has the advantage that the growth of graphene can be optimized completely independently from the substrate, enabling high-quality graphene to be integrated, without exposing the substrate to high temperatures. However, it also poses challenges, since the transfer procedure can result in imperfections in the CVD graphene due to (polymer) contamination, membrane fracture, wrinkling, and strain non-uniformities . The graConsidering the aforementioned drawbacks of transfer-based graphene flows, it is of interest to investigate alternative ’transfer-free’ methodologies, where the graphene is grown directly on the substrate, such that the transfer process can be eliminated. However, the number of substrates on which graphene can be grown has appeared to be limited. Moreover, the high electrical conductivity and reflectivity of the transition metal substrates that are commonly used for graphene growth prohibit many device applications. A notable exception appeared to be silicon carbide, which allows direct growth of single-layer graphene on its surface and is still a strong contender for enabling graphene integration, despite the high price of crystalline silicon carbide wafers limiting production volumes.An alternative route towards transfer-free graphene growth on silicon wafers is the use of a seed layer that is deposited on top of the substrate wafer for growing graphene. For such growth using a seed layer, the transition metals Cu, Ni, Mo and Pt, on which CVD graphene growth has been established, are logical choices. With Mo and Pt being the preferred seed materials, since Ni and Cu tend to form silicides or diffuse into the silicon faster.During the last years, it was shown that few-layer CVD graphene can be grown on Mo seed layers  that are2/Pt interface, as shown in 2 interface, after which the Pt seed layer is removed. This process reduces organic contamination, mechanical stress and other potential challenges of transfer-based process flows. Moreover, we show that an additional intermediate, adhesion layer of thin film of Ta metal between Pt and SiO2 can locally inhibit the graphene growth with designed patterns. A similar study has been done by implementing a Ni thin film as a seed layer [In this work we explore another route toward transfer-free graphene integration by using Pt seed layers in a process flow where graphene grows beneath the seed layer, at the SiOed layer ; howeverPlatinum was one of the first transition metals that was used as a substrate for graphene CVD growth ,17,18,19When graphene is grown on Cu or Ni foils, the foil is often etched away after the growth process. However, Pt foils are costly, and reuse of the foils is therefore often preferred, which has led to the development of processes to delaminate the graphene from the Pt surface , or grow2, thin platinum PVD films with a thickness of 50 nm are evaporated from a Pt target (99.95% purity). The platinum films are annealed at 1000 °C under atmospheric conditions or in nitrogen gas at 1 bar for 60 min, resulting in a typical Pt grain size of ∼0.5–1.0 µm as observed from the SEM and AFM, see 2 and ∼12.6 nm for N. Since differences were small we will further on only present results using the nitrogen anneal. This pre-anneal was found to be essential to prevent dewetting of the Pt film during subsequent growth of graphene and overall improves the continuity of graphene deposition.A 100 mm silicon wafer with a 90 nm thick film of thermally grown silicon dioxide is used as base substrate. On top of the SiO2 gas at a pressure of 25 mbar, at 950 °C, while using methane gas as carbon atom precursor. Subsequently, the whole system is gradually heated up to 920 °C and kept stable for about 5 min before adding methane to the CVD chamber. For graphene growth, a CH4 gas flow of 30 sccm is applied for a duration of 150 s, after which the sample is cooled down. For ensuring high quality graphene growth, a fast cool-down of the sample at a rate of 50 °C/min was applied.Graphene is deposited on these substrates using an Aixtron BlackMagic Pro cold-wall CVD system in a mixture of Ar and H2 surface and subsequent patterning by lift-off. Subsequently, a Pt thin film was evaporated, and graphene was grown using the same method described above. Ta was chosen for its high-temperature compatibility and because it withstands the aqua regia Pt etchant.Besides the growth on blanket wafers, graphene was also grown on substrates with patterned Ta structures, as shown schematically in 3 (99%)) in 4 min and subsequently the wafer was rinsed in DI water and air-dried.To assess whether graphene grows under the Pt seed layer like in c, the PtThe presence and the quality of graphene was investigated by a Renishaw inVia Reflex Raman spectrometer. The Raman microscope is equipped with a He-Ne laser (−1 was found, close to that of monolayer CVD graphene [−1 was found. Similar spectra were taken at different positions on the wafer, from which a mean integrated peak ratio 2 before Pt deposition and CVD graphene growth. Using Raman spectroscopy after Pt removal, it was established that graphene was only present on the SiO2 in between the Ta structures, and not on the Ta structures. A Raman spectrum of graphene on SiO2, with peak ratio and FWHM corresponding to monolayer graphene, is shown in terature ,27,28 ha2/Pt interface, since the adhesion forces between these surfaces are weak because Pt does not form chemical bonds with the SiO2 surface. Possibly, the low surface roughness of the SiO2 will promote the flatness and quality of the graphene growth and the purity of the layer might be increased by the requirement for the carbon atoms to diffuse through the Pt. Although no Raman signs of graphene growth were found on top of the Pt layer, we cannot fully exclude its presence since the Raman signal of graphene on Pt is very weak [2/Ta interface because of the chemical bonds between Ta and SiO2, and the low diffusivity of carbon in Ta at the graphene growth temperature [2 interface, we present an optical micrograph of the wafers with patterned Ta after CVD graphene growth in 2, which might both be a cause and an effect of the CVD graphene layer growth between SiO2 and Pt. Besides acting as a blocking layer, the Ta metal might be used as electrode material. However, in the characterized samples it was observed that no electrical contact was formed between the graphene on SiO2 and the Ta metal. Additional process steps, or local etching of Pt might be used to establish electrical contacts.The basic mechanism ,30 of inery weak . We alsoperature . As addi2. The high diffusivity of carbon in Pt, the high melting temperature and the high chemical inertness and catalytic activity of platinum metal make it ideally suited to promote the discussed growth mechanism. The ability to grow graphene directly on silicon substrates is clearly advantageous, since it circumvents the need for potentially detrimental graphene transfer steps. Moreover, we demonstrated selective graphene growth by using Ta thin films, which omits the need for graphene patterning steps. By process tuning, the quality of the graphene can probably be much further improved and integrated to provide a path towards high-quality graphene devices in application areas for sensing, data processing and high-speed communication.We present a route for the direct growth of graphene on a silicon dioxide surface at the interface between Pt and SiO


Brain-derived Neurotrophic Factor (BDNF) binds to the TrkB tyrosine kinase receptor, which dictates the sensitivity of neurons to BDNF. A unique feature of TrkB is the ability to be activated by small molecules in a process called transactivation. Here we report that the brain neuropeptide oxytocin increases BDNF TrkB activity in primary cortical neurons and in the mammalian neocortex during postnatal development. Oxytocin produces its effects through a G protein-coupled receptor (GPCR), however, the receptor signaling events that account for its actions have not been fully defined. We find oxytocin rapidly transactivates TrkB receptors in bath application of acute brain slices of 2-week-old mice and in primary cortical culture by increasing TrkB receptor tyrosine phosphorylation. The effects of oxytocin signaling could be distinguished from the related vasopressin receptor. The transactivation of TrkB receptors by oxytocin enhances the clustering of gephyrin, a scaffold protein responsible to coordinate inhibitory responses. Because oxytocin displays pro-social functions in maternal care, cognition, and social attachment, it is currently a focus of therapeutic strategies in autism spectrum disorders. Interestingly, oxytocin and BDNF are both implicated in the pathophysiology of depression, schizophrenia, anxiety, and cognition. These results imply that oxytocin may rely upon crosstalk with BDNF signaling to facilitate its actions through receptor transactivation. The animal research experiments were approved according to the NYU Institutional Animal Care and Use Committee (IACUC) of New York University Langone Medical Center. Primary cortical neurons were isolated from E18 mice, cultured on poly-D-Lysine coated coverslips or 6-well plates, and maintained for a week via Western blotting to probe for pTrkB (Y816) and total TrkB.Brain slices were collected from the somatosensory cortical area, piriform cortex, and auditory and incubated in oxygenated artificial cerebrospinal fluid and collected at 15 min, 30 min, or 1 h after oxytocin treatment or incubation alone in the control chamber. Lysates were prepared and run Human embryonic kidney 293 (HEK-293-TrkB) cells were obtained from Hiroyuki Nawa  and protein extracts from mouse uterus and brain. Untransfected HEK293 cells, as well as tissues from the oxytocin-receptor knock-out uterus and brain, were used as controls in each Western blot analysis. e compared the immune and preimmune sera by immunoblotting with different amounts of pure target OXTR-2 peptide. No reactivity was observed in the preimmune bleeds, but higher levels of reactivity were observed with increasing amounts of OXTR-2. We then used HEK293T cells transfected with OXTR-IRES-Venus cDNA to express oxytocin receptors and the Venus YFP variant in the same cells. In Western blots from oxytocin-receptor-expressing HEK cells, we observed a protein band at 43 kDa that corresponded to the expected molecular weight of the mouse oxytocin receptor.The OXTR-2 antibody was generated against the following sequences EGS-DAAGGAGRAALARVSSVKLISKAKI  in the third intracellular loop. These target peptides were chosen based on a high level of antigenicity using the Thermo Scientific Antigen Profiler. We identified epitopes that were maximally different from corresponding regions of the vasopressin V1a/V1b receptors. BLAST analysis was performed to ensure the uniqueness of these sites in the mouse proteome. The peptides were generated by AnaSpec with a terminal cysteine added to each peptide to allow for conjugation to key-hole limpet hemocyanin (KLH). KLH conjugation and injection into rabbits were performed by the Pocono Rabbit Farm and Laboratory. Each rabbit was injected with the respective peptide solution biweekly and a small bleed was collected monthly. The resulting polyclonal antisera were tested using dot and Western blot and immunohistochemistry before being further purified using affinity chromatography. Specificity of antibodies was evaluated Both brain sections and cortical neurons fixed on coverslip were incubated with primary antibodies in donkey serum/PBS/Triton at 4°C overnight, followed by incubation with secondary fluorescence antibodies. pTrkB immunoreactivity in primary cortical neurons was revealed using Alexa-Fluor 488 as the immunolabel. DAPI was used as a fluorescent stain for DNA .Total RNA was extracted from the cortex, hypothalamus, and HEK-293TrkB cells using Trizol. cDNA was generated using qScript cDNA SuperMix (QuantaBio). Quantitative real-time PCR (qRT-PCR) analysis was performed using SYBR Green PCR Master Mix (Applied Biosystem) and a StepOnePlus Real-Time PCR System (Applied Biosystem). Primers from Yang et al.  are listOXT_hum_for. 5’-GCTGAAACTTGATGGCTCCG-3’OXT_hum_rev. 5’-TTCTGGGGTGGCTATGGG-3’Actin_hum_for. 5’-TCCCTGGAGAAGAGCTACGA-3’Actin_hum_rev. 5’-TGAAGGTAGTTTCGTGGATGC-3’Actinb_ms_for5’-TGTGACGTTGACATCCGTAAA-3’Actinb_ms_rev5’ GTACTTGCGCTCAGGAGGAG-3’OXT_ms_Fw5’-GAGGAGAACTACCTGCCTTCG-3’OXT_ms_Rv5’-TCCCAGAAAGTGGGCTCAG-3’N = 12, six of each sex). There are many mechanisms that may account for TrkB receptor activation through oxytocin. We are aware that transactivation may not be responsible for all the actions of oxytocin. One possibility is the trophic effects of oxytocin, which might be mediated by TrkB receptor signaling.Mouse samples for cortical slices and primary neuronal cultures are: (i) matched for experimental and control groups for age and sex; (ii) randomized the selection of mice; (iii) and excluded mice with abnormalities; additionally; and (iv) the cell line experiments were reproduced at least three times. We are aware of the potential variability in the results due to sex and age differences. We have included a similar number of males and females of the same age in our study design. For example, in previous proteomic studies, we will examine dams and male C57BL/6 mice  or Image J to calculate statistics. Depending on the results, we utilized ANOVA tests followed by post-hoc Tukey. This analysis was specifically described in each Figure legend.The results represent the average of at least three independent experiments unless indicated. Statistical significance was determined by One-way repeated measures of variance (ANOVA) or Student’s p values equal to or less than 0.05 were considered significant, asterisks denote statistical significance . p-values are calculated using either two-tailed unpaired Student’s t-test or ANOVA followed by post-hoc Tukey test.The All described data are contained in the manuscript.via a GPCR mechanism, without the involvement of neurotrophins . For these studies, we used a pTrkB antibody that recognized a C-terminal phosphotyrosine site at Y816  and collected at 15 min, 30 min, or 1 h after oxytocin treatment or incubation alone in the control chamber. Tissue from each condition was collected from the somatosensory cortical area, piriform cortex, and auditory cortex. Lysates were prepared and processed for immunoblotting to probe for the levels of phospho-TrkB (Y816) and total TrkB, as shown in the schematic in A time course from 15 min to 1 h showed a modest increase in pTrkB, in its full length form at approximately 140 kDa . A quantIn this analysis, two forms of TrkB were visualized by immunoblotting. Interestingly in this preparation, a smaller TrkB precursor at 110 kDa was observed which was detected after oxytocin treatment. The smaller isoform represents an unprocessed and underglycosylated species. Indeed, the smaller TrkB isoform protein was detected with the phospho-TrkB Y816 antibody and has been associated with TrkB receptors found in intracellular locations. The smaller unprocessed form of TrkB has been observed in other studies , which is consistent with other experiments. A quantitation of the TrkB-Fc treatment compared with the effects of TrkB-Fc plus oxytocin is shown in in vitro assay to evaluate whether oxytocin receptor transactivates TrkB. This was done to test whether the transactivation event could be observed in a heterologous background. This is an important question, as it addresses whether these receptor molecules are sufficient for transactivation. Therefore, the HEK293 human cell stably expressing TrkB  receptors. In these kB cells . HoweverkB cells . DAPI stThe results of the HEK293-TrkB experiments recapitulated the activation of phosphorylated TrkB receptors observed in primary neurons presented in One explanation for the apparent ligand independence of transactivation is that expression of endogenous oxytocin ligand might occur in heterologous cells. To address this possibility, we carried out measurements of oxytocin ligand RNA isolated from cortex and hypothalamus and HEK-293TrkB cells by RT-qPCR. Primers for the human transcript were used to assay HEK-293 cells and primers for mouse oxytocin mRNA were used for the mouse cortex and hypothalamus.Negligible levels of oxytocin message were found in the HEK-293 cells by RT-qPCR measurements . In contIn order to elucidate the role of oxytocin receptors during transactivation, we carried out an immunofluorescence analysis of oxytocin and TrkB receptors. The introduction of a myc-tagged oxytocin receptor vector in HEK293-TrkB cells gave rise to ample expression, which was effectively visualized with a myc-antibody .in vitro experiments, only low levels of endogenous expression of pTrkB were observed in HEK293-TrkB cells (The transfected cells were tested for phospho-TrkB (Y816) receptors. In these kB cells . HoweverkB cells . DAPI stkB cells .To assess the specificity of the oxytocin receptor’s transactivation activity toward TrkB, we assessed the ability of a related vasopressin receptor in this assay. Vasopressin has three receptor isoforms, V1aR, V1bR, and V2R, which belong to the family of seven transmembrane receptors with highly similar sequence identity to the oxytocin receptor . A significant reduction of pTrkB induced by BDNF was observed with K-252a treatment. As another test, increasing concentrations of oxytocin were applied to elicit transactivation. Application of the K-252a inhibitor resulted in a decrease in the level of transactivation of pTrkB (Y816) receptors in cells treated separately with oxytocin .Inhibition of TrkB resulted in a decrease of gephyrin expression by oxytocin. One explanation for the effects of oxytocin and TrkB upon the gephyrin protein is that oxytocin acts by transactivation. This possibility is supported by previous findings that BDNF is capable of promoting gephyrin expression and clustering  can transactivate Trk receptors with a similar time course and mechanism (Lee et al., Since small molecules are capable of targeting populations in the CNS, it is conceivable that oxytocin might use TrkBreceptor as a downstream signal to increase trophic support as well as dendritic and axonal branching and synaptogenesis. Hence in the future, oxytocin could potentially be considered as a treatment of neurological and psychiatric disorders through a transactivation mechanism with different G protein-coupled ligands.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.MM, MC, and RF designed the research. MM, KS, KW, and LK performed the experimental research. MC and MM wrote the manuscript. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Exposure to green spaces contributes to residents’ physical and mental health and well-being. The equitable allocation of green space has also become an increasingly important issue for society and the government. This study takes 3281 communities in Shenzhen as the analysis units. Using web crawlers, semantic segmentation based on deep learning, web map path planning and entropy weighting methods, four types of residents’ daily green exposure indicators are calculated, including community green space ratio, green view index (GVI), park accessibility, and the weighted composite green exposure index. The results reveal inequalities in the level of green exposure in Shenzhen’s communities across economic classes, mainly in GVI and comprehensive green exposure. We also found that the level of composite green exposure is relatively stable; however, green space ratio attainment levels for newer communities are increasing and GVI and park accessibility attainment levels are decreasing. Finally, among the newly built communities: compared to the low-income level communities, the high-income level communities have a significant advantage in green space, but the mid-income level communities do not have such an advantage. The main findings of this study can provide policy implications for urban green space planning, including the need to prioritize the addition of public green space near older communities with poor levels of green exposure, the addition of street greenery near communities with poor levels of composite green exposure, and ensuring that parks have entrances in all four directions as far as possible. In the context of Chinese cities, one of the most common concerns is socio-economic inequality. Indeed, studies reveal that China has shifted from a relative doctrine of equality to a society marked by increasing economic disparity since the policy of the socialist-oriented market economy .The public resources represented by green spaces can increase housing prices in the surrounding communities ,3,4. EspThis article attempts to quantify the equity of community green exposure. The potential mechanism of human exposure to green space has been referred to as green exposure ,9,10. WeLabib et al., based on the definition of green exposure provided in the existing studies, classified the concept of green exposure into availability, visibility, and accessibility . FirstlyGreen space is a common generalized term used to describe natural areas in urban environments, such as parks, community gardens, and public green spaces ,19,20. TIn previous green exposure assessment studies, the green space objects are mainly parks, and few studies capture the problems of finer-scale green space . In factEarly on, urban green land ratios and per capita green areas were used to reflect the spatial construction level of urban green space in different regions; later, urban green space was studied for spatial equity and social equity . Urban pAccess to green space is a significant environmental justice issue. It means that everyone has the right to be protected from specific environmental issues (such as pollution and climate change) and to obtain standard services (green spaces) . Green sMladenka et al. use empirical evidence from Chicago to show that socio-economic class may be a determining factor in the distribution of green space . NumerouAs technology continues to evolve, there are breakthroughs in acquiring community built-up time data and quantifying new types of green data. Firstly, obtaining community built-up time data published by developers on real estate transaction websites allows for a comparative assessment of green exposure in communities with different built-up periods. Community green space ratio from real estate websites can also support fine-scale assessment of green space within communities ,51. SecoIn summary, most existing green justice studies focus on park-oriented green objects, ignoring the fine-scale greenery that community residents are more frequently exposed to ,27,43. MIn other words, the latest data and methods are bringing fresh research possibilities to the fore. Our study incorporates green equity measures into more green data and introduces a time-based perspective to evaluate many types of green exposure levels in communities of different economic levels. This could help to accurately assess community green space equity and propose more precise green strategies.2, 980 km2 of which were built-up areas, and the city’s resident population had reached 17.6 million; with the city’s built-up area greening coverage rate of 43.38%, and a built-up area green space rate of 37.36%, the greening indicators ranked among the top in the country [Shenzhen is near Hong Kong and is part of the Pearl River Delta. Shenzhen has become one of China’s most populous and inventive cities since the Special Economic Zone was established in 1979. Although Shenzhen’s urban spatial structure is polycentric, there is a clear difference in urban development between the north and the south, based on the central boundaries of the city. At the end of 2020, the city covered an area of 1995 km country . HundredThe city is divided into ten administrative districts, as shown in Data access.https://sz.fang.com/ (accessed on 30 March 2021)) by the web crawler, which is one of the top three trading platforms for online housing in China. It was the first to be established and covers the largest data and number of website hits. The community data was gathered using the crawler technique, which included particular location, price, community kind, community age, and green space rate. Ultimately, after data clearance, we obtained information on 3281 observations in Shenzhen.Communities’ data were captured on the FANGTIANXIA website  to obtain each community’s latitude and longitude coordinate information. The residential points were projected onto a base map in ArcGIS. Using the Baidu Maps API (Application Programming Interface), a search was made by latitude and longitude of each community to obtain the actual boundaries of each community .2.Community economic classification.3281 communities were divided into five equal numbers of partitions ,17. Then3.Community built-up period classification.The particular year of housing reform, 1998, characterized by privatization and marketization, was used as the dividing point ,16, follThe community green space ratio is almost unchanged since the community was built, while the street greenery and parks (amount) are generally getting better all the time. Note that, due to the time limitation of street view images (SVIs) and park data acquisition, we only assessed the community green space by the current state of urban green space. Communities of different built-up periods were then grouped to compare their green exposure level.Green space data was collected in and around communities, including green spaces within the community, green spaces in streets around the community, and urban parks.Community green space.2.Street greenery.The vegetation in the street view images collected using the Baidu Map API is depicted in 3.Park.As shown in Community green space data is obtained directly from real estate websites and reflects the ratio of community green space to the total community area.Shenzhen Urban Planning Standards and Guidelines (2013), the width of urban roads in Shenzhen is 12 to 80 m. Therefore, a 100 m buffer can cover the sampling points around the community.The visibility metric represents the green space that community residents can see and perceive on the street. This study defines the resident activity area as the Euclidean buffer zone of 100 m around the community boundary outwards (excluding the community itself). The reason for choosing this distance is that, according to the The pyramid scene parsing network (PSPNet) is a pixel-level object detection and classification method that generates solid semantic segmentation results, with pixel-level accuracy of more than 80.2% . It has Finally, each community’s GVI is the average of the GVI values of all street points within the community’s 100 m boundary buffer. Each community has an average of 45 street points within its buffer zone, with a minimum of 10 points.Accessibility indicators describe the distance from the community to the nearest park. As the location of households in each community varies, when regarding departure points, using the community center point as the departure point can be considered the average location for all community residents to depart from. Regarding destinations, we defined the centroid and entrances of green spaces as destinations according to the level of the green space ,60,61. TAmap is a web map similar to Google Navigation ,62. A maStandard for urban residential area planning and design (GB50180-2018), a 30% green space rate was selected as the benchmark for community green space attainment. Next, the 10 min (800 m) walking distance was selected as the benchmark for park accessibility, based on the Spatial planning guidance to the community life unit (TD/T1062-2021). Finally, there is no national-level evaluation standard for street greening in China. Referring to the official document issued by the Ministry of Land, Infrastructure, Transport and Tourism, which is responsible for urban construction in Japan [Considering that different green spaces have different contact standards, we produced an evaluation standard through the normative standards of different green spaces. First, drawing on China’s residential area design code, in Japan , a 25% gStandardization of green indicators.Using standardized and entropy methods to calculate the comprehensive green evaluation index of each community, which is comprehensive in order to consider the green exposure level of the community, the calculation steps are as in Formulas (2) to (5):The level of community green exposure varies considerably under the same green indicator. To measure more the difference between the level of green exposure and the ideal standard , this stPositive indicator:Inverse indicator:2.Determination of green indicator weights.n is the total number of elements.The chi-square test is a very versatile hypothesis test for counting data, the purpose of which is to compare the degree of agreement or goodness of fit between the theoretical and actual frequencies. This method was used in this study to verify whether there was a significant difference in the level of green space compliance between high- or mid-income level communities and low-income level communities.If the results of the chi-square test are not significant, the original hypothesis cannot be rejected. It indicates that high- or mid-income level communities tend to have no significant difference in the attainment level of green exposure from low-income level communities; conversely, if the results of the chi-square test are significant, the original hypothesis is rejected. It indicates that high- or mid-income level communities tend to differ significantly from low-income level communities in terms of their attainment level for green exposure.Finding areas with weak levels of community green exposure.n is the total number of elements; The local Getis-Ord Gi* index is a local spatial autocorrelation index based on a distance weight matrix that detects high-value and low-value aggregation. This study analyses the degree of community green exposure aggregation at the local spatial level. The calculation formula is as follows.2.The spatial relationship between communities’ age and price and green exposure levels.N-by-N Euclidean distance weighting matrix for the spatial correlation between Using global bivariate Moran’s I, the spatial connection between community price and three forms of green exposure was studied. With the following computation steps (8) and (9), these analyses were used to examine spatial correlations across the research area :(8)IP,A=The values of bivariate Moran’s I range from −1 to 1. For the bivariate Moran’s I with statistical significance, the positive and negative values indicate spatial aggregation  and spatial fragmentation , respectively . The cluSpecifically, the structure of the data is shown in The spatial distribution of green spaces ratio, GVI, and accessibility was analysed in hotspots (Getis-Ord Gi*), and the results were visualized . The LuoUsing the baseline values of green space ratio, GVI, and accessibility, entropy values and weights were further calculated . FinallyFurther analysis through the hotspot analysis  reveals Standard deviation ellipses are commonly used to describe the spatial characteristics of geographical distributions, such as trends in concentration, dispersion, and trends in the direction of distribution . This stThe spatial distribution of communities of different economic classes is shown in The results of green space levels in communities of different economic classes are shown in After the level of green exposure has met the specification, absolute equality is no longer sought. Therefore, we further counted the level of attainment rates for green exposure in communities of different economic levels, and the results are shown in The results of our study in Shenzhen show that communities in central urban areas benefit more from public green facilities (GVI and park accessibility) than those in non-central urban areas. However, the central urban areas of Luohu and Futian district have a poorer community green space ratio. In comparison, the non-central areas have a better community green space ratio. Differences in community public green space are attributed to Shenzhen’s spatial distribution of green space resources. In contrast, private green space differences are attributed to communities’ built-up period.Firstly, we present an overview of the public green facilities. The Code of urban Residential Areas Planning & Design (GB50180-93), introduced in 1993 and implemented in 1994, began to emphasize the requirement for a green space ratio in communities, which means that the green space ratio in newly built communities should not be less than 30%. On the one hand, the earlier (pre-1994) built communities were not subject to this design standard; on the other hand, the later communities were mostly gated, and the concept of community green space began to take form and was gradually taken into account [Next comes private greenery, where the age of the community heavily influences the level of community green space.  account . So the p < 0.01), revealing a positive spatial correlation between year of community completion and green space rate. The relationship between community age and green space ratio is further shown in the clustering diagram of the local bivariate Moran’ I index , respectively  built-up communities, the attainment rates for the three green space levels and the comprehensive green exposure level have been almost equal between low-income and mid-income levels. Even in the communities built from 2004 to 2013, the attainment rates for park accessibility levels in low-income level communities have been significantly stronger than those in mid-income level communities.Low-income level communities were used as the control group, and mid-income and high-income level communities were treated as the experimental group, respectively. The chi-square test in SPSS was used to explore whether there were significant differences in the attainment rates of green space ratio, GVI, accessibility, and comprehensive green exposure indicators between the groups of communities of different economic levels at different built-up periods.The chi-square test results further confirm our view . OverallFinally, among the most recently built-up communities (2014–), only high-income level communities have a significant advantage over lower-income level communities in terms of park accessibility and comprehensive green exposure levels, with mid-income level communities no longer having a significant advantage. This is a phenomenon showing less social inequality, as access to qualifying levels of green space is not very different for all but the wealthiest.New communities are increasing their green space attainment rates based on the development trend of the built-up period. Still, GVI and park accessibility are generally lower than in previously built communities. These figures suggest the rising level of private greenery and the declining level of public greenery.Private green spaces.The relationship between the timing of community completion and green space rates is explained in the previous Public green spaces.On the one hand, current green space planning in China is based on a ‘top-down’ model, which, due to land constraints, does not complement public green space as easily as private community green space. Previously built-up communities already occupy good locations, and even in the same area new communities can only gradually move away from public green space. On the other hand, with the rapid growth of cities and the increasing size of built-up areas, the suburbanization of the residential population is a common phenomenon in large cities. However, urban green space is expanding slowly and has become a scarce resource, creating a spatial mismatch between its supply and demand .Urban renewal in downtown communities.With the level of private green space tending to be consistent across different economic classes and communities, the planning of public green space is a major concern for future green justice. Urban renewal and the suburbanization of green spaces have raised the level of green exposure in high-income and low-income level communities. This is why high-income level communities maintain the highest level of public green space most of the time, while low-income level communities can surpass the level of public green space of mid-income level communities during a certain period (2004 to 2013). Typical cases are as follows:A 74F super high-rise residential development located in the heart of Shenzhen’s downtown area, at Baishi Zhou, is surrounded by excellent greenery, with the OCT National Wetland Park to the east and the Dasha River Ecological Promenade to the west, both within a 10-min walk. This part of the residential block is planned to be built on the site of the old Baishi Zhou urban village redevelopment project. In urban regeneration, high-income inhabitants will be drawn to newly developed communities, while former low-income people will be screened out as part of the environmental gentrification process; approximately 150,000 low-income Baishi Zhou inhabitants have been displaced to low-quality communities on the edge of the city.The suburbanization of green space.Communities within the center of Longgang district in the northeast of Shenzhen, which are mostly of low-income level, have benefited from the Greenland suburbanization strategy. Because the 2011 Shenzhen Universiade was held right in the center of the Longgang district, the big event led to massive investment in green infrastructure, including new parks and improved street greening. Public green spaces in the region have been significantly enhanced . RegardiThe 2008 Olympic Games in Beijing and the 2010 Youth Olympic Games in Nanjing were also major sporting events. However, the venues tend to be on the edge of the downtown area and not really in the city’s suburbs. The results did not enhance the green infrastructure for low-income groups ,72.The impact of this trend on residents is not as bad as one might think. Firstly, the community green exposure attainment level trended consistently across economic classes (excluding low-income level communities in the period 1980–1993 to 1994–1998), reflecting social equity ; privateThe communities’ comprehensive green exposure level remains stable, suggesting some substitution between the various types of green space. Similarly, Zhang et al.  and XiaoFirstly, green space planning can be improved by considering communities’ green needs at different economic levels. Woo and Webster point out that traditional public goods provided by the government, such as urban green spaces, may be partially or completely replaced by club goods . TherefoSecondly, we have studied spatial inequalities between the three types of green space in Shenzhen, which can help municipalities and planners to identify where and what they should invest more resources in to improve communities’ green exposure. In Shenzhen, this work has identified a gap: only 31.3% of communities meet all three basic objectives for green space simultaneously, with the vast majority (68.7%) of the remaining communities still not meeting it. Previously, we have added up the scores of the three green indicators for the community with the help of Standardization and Entropy Weighting and then analysed them based on the hotspot analysis . FurtherIn practical terms, community green spaces and parks are difficult to change; meanwhile, Xu et al. confirmed through VR experiments that streets with high GVI could replace places such as parks and green spaces as places for residents to release their stress . TherefoFinally, creating new parks is essential, but parks are the most difficult green spaces to add because of land and economic constraints. The ParkScore index by The Trust for Public Land (TPL) suggests that, in some cases, cities can improve park accessibility by adding new park entrances . That isNearly 70% of Shenzhen’s municipal parks currently do not guarantee access in all four directions, and about 30% of municipal parks have access in only one to two directions, indicating that there is still much potential to improve accessibility. Specifically, as in It should be added that our emphasis is on the concept’s feasibility rather than the precise layout of each park entrance.The equitable distribution of green space is becoming more recognized as an issue of environmental inequality in China. This study uses multi-source big data to explore the green exposure inequality in built-up communities over time. The results show that: (1) green space ratio, GVI, accessibility, and comprehensive green exposure levels of Shenzhen’s communities are unevenly distributed among different economic classes, with lower-income level communities having poorer green exposure. (2) Compared to the old communities, the newly built communities have a higher green space ratio, lower GVI, and the comprehensive green exposure level scores remain stable. (3) Among the newly built-up communities, high-income level communities have a significant green space advantage over low-income level communities, but the difference between the mid-income and low-income level communities is not significant.This study implies that, firstly, the differences in the level of community green space may be related to the uneven spatial distribution of green space resources in Shenzhen. Then, the differentiation of urban residents’ needs and abilities allows people with high economic attributes to live in communities with better levels of green space, building gaps in the level of community green space among different economic classes. Secondly, the level of private green space in newly built-up communities is increasing, while the level of public green space is decreasing. This trend is influenced mainly by residential design regulations and land constraints, but is not very bad, as green spaces are interchangeable. Finally, government planning for green facilities includes ‘green gentrification’ and green space planning derived from major (sporting) events. It has continued to give upscale communities a significant green space advantage and has helped close the green space gap between low and midscale communities.For future green space planning, three policy implications are highlighted: (1) street greening should be enhanced in areas with weak performance in terms of comprehensive green exposure levels, (2) communities with poor private green spaces should be prioritized to enhance public green spaces around them, and (3) accessibility should be enhanced by ensuring that parks have entrances in every direction as far as possible.Our study has some limitations. Firstly, the GVI indicator is calculated from the greenery within 100 m of the community boundary, which is only relevant to those residents living directly within the community boundary. People whose daily activities pass through these areas also benefit from GVI. Secondly, park accessibility only takes into account the distance from the community to the nearest park and does not take into account the quality and quantity of parks within a certain range. Finally, some fee-paying parks were excluded from the study, but they may meet the daily use needs of some wealthy people. For example, residents of the community surrounding Happy Valley Park who have an annual pass can obtain free daily access to the fee-paying parks. The benefits of access to parks for the wealthy may have been underestimated.


Ultra-sensitive and responsive humidity sensors were fabricated by deposition of graphene oxide (GO) on laser-induced graphene (LIG) electrodes fabricated by a low-cost visible laser scribing tool. The effects of GO layer thickness and electrode geometry were investigated. Sensors comprising 0.33 mg/mL GO drop-deposited on spiral LIG electrodes exhibited high sensitivity up to 1800 pF/% RH at 22 °C, which is higher than previously reported LIG/GO sensors. The high performance was ascribed to the high density of the hydroxyl groups of GO, promoted by post-synthesis sonication treatment, resulting in high water physisorption rates. As a result, the sensors also displayed good stability and short response/recovery times across a wide tested range of 0–97% RH. The fabricated sensors were benchmarked against commercial humidity sensors and displayed comparable performance and stability. Finally, the sensors were integrated with a near-field communication tag to function as a wireless, battery-less humidity sensor platform for easy read-out of environmental humidity values using smartphones. Humidity sensors play an important role in many industrial and day-to-day life applications including environmental monitoring, smart agriculture/home, health, consumer electronics, and the IoT ,2,3,4. U2 lasers) of polyimide films leads to the formation of an electrically conductive laser-induced graphene (LIG) material [3 carbon atoms into sp2 carbon atoms and the formation of conductive and porous structures [−3% RH [In recent years, direct laser writing methods have been extensively used for the fabrication of graphene-like materials on flexible polymer substrates ,25. In tmaterial ,27,28. Pructures ,25. The ructures ,30 and fructures  and biosructures  for enviructures ,34 and hructures . Recentlructures . In anot [−3% RH .In this work, we fabricated ultrasensitive humidity sensors by the combination of spiral LIG electrodes and GO layers. A 450 nm laser was used. The sensors displayed a wide operating range (0–97% RH), excellent stability, and short response/recovery times. Sensor functionality was studied in the temperature range of 19 °C–27 °C. The effect of GO thickness was investigated, as well and the difference between spiral and interdigitated electrode geometries. In its optimized conditions, the sensor exhibited sensitivity of 1800 pF/% RH at 22 °C and response/recovery times shorter than 16 s. The sensor was also integrated into a near-field communication tag to function as a wireless, battery-less humidity sensor that could read environmental humidity values using a smartphone.3COOK), magnesium chloride (MgCl2), potassium carbonate (K2CO3), magnesium nitrate (Mg(NO3)2), copper chloride (CuCl2), sodium chloride (NaCl), potassium chloride (KCl), and potassium sulphate (K2SO4) were purchased from SIGMA ALDRICH and used directly without any further modification. Polyimide films with a thickness of 80 μm were purchased from Radionics and used without further treatment. All solutions were prepared using deionized Milli-Q water .Sodium hydroxide (NaOH), lithium chloride (LiCl), potassium acetate  on the LIG electrodes. GO was synthesized based on a two-step oxidation process, as previously reported , where s−1 nominal spring constant of the cantilever. Raman Spectra were taken with at 514.5 nm (2.41 eV) laser using a MicroRaman  setup. The laser power was kept below 1.5 mW on the sample to avoid laser-induced local heating, while an Olympus MPLN100x objective (NA = 0.90) was used to focus the beam on the samples. The XPS measurements were carried out in an ultra-high vacuum system (UHV), which consists of a fast entry specimen assembly, a sample preparation, and an analysis chamber equipped with a dual anode (Al/Mg) X-ray gun and an LH10 electron analyzer. The base pressure in both chambers was 1 × 10−9 mbar. The unmonochromatized MgKα line at 1253.6 eV and an analyzer pass energy of 36 eV, giving a full width at half maximum (FWHM) of 0.9 eV for the Au 4f7/2 peak, were used in all XPS measurements. The XPS core level spectra were analyzed using a fitting routine, which can decompose each spectrum into individual mixed Gaussian-Lorentzian peaks after a Shirley background subtraction. The sample was mounted onto a Si substrate with dimensions 1.5 × 1.5 cm2. Finally, the capacitance and impedance of the sensors were recorded by a computer-controlled LCR .The morphological characterization of the obtained sensors was performed by a cold-cathode field-emission scanning electron microscope  operating at a 5 kV acceleration voltage. AFM images of the sensor surface were collected by contact mode . Images were obtained using ScanAsyst-Air probes  with a 0.4 N m2 flow, which provided a stable and controlled RH level at their equilibrium states in a closed container 2, CuCl2, NaCl, KCl, and K2SO4 in a closed vessel were used to obtain approximately 7.5%, 11%, 23%, 33%, 43%, 53%, 67%, 75%, 85%, and 97% RH levels, respectively  and sensitivity (S), determined by R = C/C0 = (Cx − C0)/C0 × 100% and S = (Cx − C0)/(RHx − RH0), where Cx and C0 are the capacitance of the sensor at the x% and 0% RH levels, respectively. For stability and repetitive measurements, a custom-made relative humidity chamber was designed for rapid switching between high and low relative humidity, at a constant temperature of 22 °C. This gas flow system is displayed in 2 flows were used for the system. The humidified air was created using two bubble systems at 50 °C and 22 °C, respectively, while for the dry air, the N2 flow was used. Finally, the different RH levels were achieved by different mixing ratios of the two flows. In addition, a commercial humidity and temperature sensor, AM2302, was used to monitor and record the humidity and temperature in the chamber, which was controlled by an Arduino UNO.vely see b. A 0% RHumidity sensors were fabricated by drop-casting GO aqueous solutions of different concentrations on LIG spiral electrodes fabricated by direct laser writing of polyimide, as illustrated in γ . In addiγ : C=. The recovery time was the time interval from the last value at 80% RH until the capacitance reached 90% of the minimum value at 0% RH (Cmin × 1.1). The recorded response time was 16 s. The recovery time was also fast, with the sensor reaching its initial capacitance value in 9 s. Furthermore, the sensor exhibited a maximum hysteresis of 3.03% at 75% RH, which was calculated based on the absorption and desorption characteristics of An in-depth characterization of the effect of GO concentration was performed. x − C0)/(RHx − RH0). Based on the capacitance values (at 500 Hz) observed in x − C0)/C0 × 100%. As shown in 3, 3430 × 103, 3604 × 103, and 11,710 × 103% were calculated for the same RH range, for the sensors developed using 0.33, 0.67, 1.33, and 2 mg/mL GO dispersions, respectively. Both R and S can be considered as figures of merit for the sensors—they express the variation of capacitance in the measured range and its fluctuations in each RH level, respectively.The sensitivity of all sensors see  was calc2) than the active area of the spiral electrodes (265 mm2). The sensing film consisted of a 50 nm GO film in both cases. 3%. However, the response and recovery time 2 solution. After an equilibrium period, the vessel was placed in the cooling chamber for 2 h, and then, it was placed under the room conditions. It was observed that both sensors instantaneously detected a drop in absolute humidity at the beginning of the cooling process, due to the lower solubility of water in the atmosphere at decreasing temperatures. The absolute humidity response of both sensors began to increase after two hours, signaling the beginning of the heating cycle, where the solubility of water molecules in the atmosphere increases as a function of temperature.Finally, the integration of the GO/LIG relative humidity sensor with a battery-less near-field communication (NFC) device was performed to demonstrate fast interrogation of the sensor using a smartphone. The developed sensor was connected to a capacitance-to-digital converter (CDC), which was interfaced with a microcontroller unit (MCU) using the Inter-Integrated Circuit (I2C) protocol, as shown in fCLK) = 0.524 MHz; I2C core input clock (fI2C_IN) = 1.028 MHz; MCU core voltage (VCORE) = 1.2 V; supply voltage (VDD) of 2.1 V. As a result, the NFC-enabled humidity sensor required a peak DC power of just 900 µW, which is one of the lowest reported in the literature [In the presented design, both voltage and frequency scaling (VFS) techniques were used to minimize the DC power consumption of the developed sensor with the aim to maximize the wireless communication range. To achieve sub-mW DC power consumption, the NFC-enabled humidity sensor was designed with optimal settings: MCU peripheral clock  was taken into consideration, and it was found that the higher surface area of the spiral design had a positive effect on the sensitivity. Compared to similar GO-based humidity sensors, the GO/LIG platform displayed comparable or superior sensitivities, a wide RH range, stability, and short response and recovery times. Finally, towards practical applications, the sensor was integrated with an NFC tag that enabled humidity readings through a commercial smartphone.