ObjectiveTo investigate the mechanism of Tangbikang dry paste in the prevention and treatment of type 2 diabetic peripheral neuropathy （DPN） based on the glyoxalase-1 （GLO-1）/advanced glycation end products （AGE）/receptor for advanced glycation end products （RAGE） pathway. MethodsA total of 56 Sprague-Dawley rats were randomly divided， with eight assigned to the normal group. The remaining 48 rats were fed a high-fat diet combined with intraperitoneal injection of streptozotocin （STZ） to induce a type 2 diabetes mellitus （T2DM） model. Based on blood glucose levels， the rats were randomly assigned to the model group， Tanglin group （13.5 mg·kg^-1）， metformin group （135 mg·kg^-1）， and Tangbikang dry paste low-， medium-， and high-dose groups （3， 6， 12 g·kg^-1）. Successful modeling of DPN was confirmed by a decrease in mechanical pain threshold in the model group at week 4. Fasting blood glucose， body weight， and mechanical pain threshold were measured every 4 weeks. After 16 weeks of intervention， the pathological morphology of the sciatic nerve was observed using hematoxylin-eosin （HE） staining. The expression of RAGE， AGE， protein kinase C （PKC）， and collagen （COL） in the sciatic nerve was assessed by immunohistochemistry. The mRNA expression of RAGE， PKC， Toll-like receptor （TLR）， COL， and GLO-1 was detected using real-time quantitative PCR （Real-time PCR）. Serum levels of aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， creatinine （CREA）， urea （UREA）， interleukin-6 （IL-6）， and tumor necrosis factor （TNF）-α were measured by enzyme-linked immunosorbent assay （ELISA）. ResultsCompared with the normal group， the model group showed significantly increased fasting blood glucose （P<0.01）， decreased body weight and mechanical pain threshold （P<0.01）， and elevated serum AST， ALT， CREA， UREA， IL-6， and TNF-α levels （P<0.01）. The expression of RAGE， AGE， and PKC in the sciatic nerve was significantly increased （P<0.01）， while COL expression was decreased （P<0.01）. The mRNA expression of TLR， RAGE， and PKC was upregulated （P<0.01）， whereas COL and GLO-1 mRNA levels were downregulated （P<0.01）. Histological examination showed irregular nerve morphology， axonal alterations， and myelin degeneration. Compared with the model group， fasting blood glucose levels in the Tangbikang dry paste high-dose group at all time points and in the medium-dose group at weeks 4 and 16 were significantly reduced （P<0.05， P<0.01）. No significant changes in body weight were observed across all Tangbikang dose groups. The mechanical pain threshold was elevated at different time points after administration in all Tangbikang groups （P<0.05， P<0.01）. Serum IL-6 and TNF-α levels were decreased in all dose groups （P<0.05， P<0.01）. The expression of RAGE， AGE， and PKC in the sciatic nerve was reduced （P<0.01）， while COL expression was increased （P<0.01）. The mRNA expression of TLR， RAGE， and PKC was downregulated （P<0.01）， whereas GLO-1 mRNA expression was upregulated （P<0.05， P<0.01）. Additionally， COL mRNA expression was significantly increased in the low- and high-dose groups （P<0.01）. Pathological changes in the sciatic nerve were milder in all Tangbikang groups compared to the model group. ConclusionTangbikang dry paste significantly improves DPN， and its mechanism may be associated with the regulation of the GLO-1/AGE/RAGE signaling pathway.

ObjectiveTo investigate the mechanism of Tangbikang dry paste in the prevention and treatment of type 2 diabetic peripheral neuropathy （DPN） based on the glyoxalase-1 （GLO-1）/advanced glycation end products （AGE）/receptor for advanced glycation end products （RAGE） pathway. MethodsA total of 56 Sprague-Dawley rats were randomly divided， with eight assigned to the normal group. The remaining 48 rats were fed a high-fat diet combined with intraperitoneal injection of streptozotocin （STZ） to induce a type 2 diabetes mellitus （T2DM） model. Based on blood glucose levels， the rats were randomly assigned to the model group， Tanglin group （13.5 mg·kg^-1）， metformin group （135 mg·kg^-1）， and Tangbikang dry paste low-， medium-， and high-dose groups （3， 6， 12 g·kg^-1）. Successful modeling of DPN was confirmed by a decrease in mechanical pain threshold in the model group at week 4. Fasting blood glucose， body weight， and mechanical pain threshold were measured every 4 weeks. After 16 weeks of intervention， the pathological morphology of the sciatic nerve was observed using hematoxylin-eosin （HE） staining. The expression of RAGE， AGE， protein kinase C （PKC）， and collagen （COL） in the sciatic nerve was assessed by immunohistochemistry. The mRNA expression of RAGE， PKC， Toll-like receptor （TLR）， COL， and GLO-1 was detected using real-time quantitative PCR （Real-time PCR）. Serum levels of aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， creatinine （CREA）， urea （UREA）， interleukin-6 （IL-6）， and tumor necrosis factor （TNF）-α were measured by enzyme-linked immunosorbent assay （ELISA）. ResultsCompared with the normal group， the model group showed significantly increased fasting blood glucose （P<0.01）， decreased body weight and mechanical pain threshold （P<0.01）， and elevated serum AST， ALT， CREA， UREA， IL-6， and TNF-α levels （P<0.01）. The expression of RAGE， AGE， and PKC in the sciatic nerve was significantly increased （P<0.01）， while COL expression was decreased （P<0.01）. The mRNA expression of TLR， RAGE， and PKC was upregulated （P<0.01）， whereas COL and GLO-1 mRNA levels were downregulated （P<0.01）. Histological examination showed irregular nerve morphology， axonal alterations， and myelin degeneration. Compared with the model group， fasting blood glucose levels in the Tangbikang dry paste high-dose group at all time points and in the medium-dose group at weeks 4 and 16 were significantly reduced （P<0.05， P<0.01）. No significant changes in body weight were observed across all Tangbikang dose groups. The mechanical pain threshold was elevated at different time points after administration in all Tangbikang groups （P<0.05， P<0.01）. Serum IL-6 and TNF-α levels were decreased in all dose groups （P<0.05， P<0.01）. The expression of RAGE， AGE， and PKC in the sciatic nerve was reduced （P<0.01）， while COL expression was increased （P<0.01）. The mRNA expression of TLR， RAGE， and PKC was downregulated （P<0.01）， whereas GLO-1 mRNA expression was upregulated （P<0.05， P<0.01）. Additionally， COL mRNA expression was significantly increased in the low- and high-dose groups （P<0.01）. Pathological changes in the sciatic nerve were milder in all Tangbikang groups compared to the model group. ConclusionTangbikang dry paste significantly improves DPN， and its mechanism may be associated with the regulation of the GLO-1/AGE/RAGE signaling pathway.

ObjectiveTo observe the effects of the South African herb Hoodia gordonii （HG） on glucolipid metabolism in diabetic db/db mice and explore the possible mechanisms of HG on the liver of db/db mice based on the phosphoinositide-3 kinase （PI3K）/protein kinase B （Akt）/factor forkhead protein O1 （FoxO1） signaling pathway. MethodA total of 30 db/db mice were randomly divided into five groups according to fasting blood glucose： model group， metformin group （0.195 g·kg^-1）， and low dose （0.39 g·kg^-1）， medium dose （0.78 g·kg^-1）， and high dose （1.56 g·kg^-1） HG groups， with six m/m mice in each group， and another six m/m mice were set as normal group. The mice in the normal and model groups were given saline of 9 mL·kg^-1 by gavage. Body weight， water intake， and fasting blood glucose of the mice in each group were measured weekly. After six weeks of continuous administration， serum insulin （FINS）， low-density lipoprotein cholesterol （LDL）， total cholesterol （TC）， triglyceride （TG）， alanine aminotransferase （ALT）， aspartate aminotransferase （AST）， urea， and creatinine （CREA） were measured， and liver sections were embedded and stained with hematoxylin-eosin （HE）， periodic acid-Schiff （PAS）， and oil red O. Protein expression of PI3K p85， p-Akt， and p-FoxO1 in liver was detected by immunohistochemistry. The mRNA expression of PI3K， Akt， and FoxO1 in liver tissue was detected by real-time polymerase chain reaction （Real-time PCR）. ResultAfter six weeks of administration intervention， it was found that fasting blood glucose was significantly downregulated in mice in the three HG groups （P<0.05）. The level of islet resistance index was significantly reduced in both the low and medium dose HG groups （P<0.05）. The expression levels of TC， TG， and LDL were reduced in all HG groups （P<0.05， P<0.01）. Pathologically， HG could alleviate hepatocyte steatosis， reduce the volume and content of lipid droplets in liver， and increase the distribution of glycogen granules in liver to some extent in mice. Immunohistochemical assays revealed that PI3K p85 protein expression was significantly increased in the low， medium， and high dose HG groups compared with the model group （P<0.01）. p-Akt protein expression was significantly increased in the medium and high dose HG groups （P<0.05， P<0.01）. p-FoxO1 protein expression was significantly increased in the low， medium， and high dose HG groups （P<0.05， P<0.01）. Compared with the model group， PI3K mRNA was increased in low dose， medium dose， and high dose HG groups （P<0.05）， and Akt mRNA was increased in high dose HG group （P<0.05）. FoxO1 mRNA was decreased in low dose， medium dose， and high dose HG groups （P<0.05）. ConclusionHG can ameliorate the disorder of glucolipid metabolism in db/db mice， which may be related to its activation of the hepatic PI3K/Akt/FoxO1 signaling pathway.

ObjectiveTo investigate the effect of Tangbikang granules on oxidative stress of sciatic nerve in diabetic rats by regulating adenylate activated protein kinase/peroxisome proliferator-activated receptor γ coactivator-1α/mitochondrial Sirtuins 3 （AMPK/PGC-1α/SIRT3） signaling pathway. MethodThe spontaneous obesity type 2 diabetes model was established using ZDF rats. After modeling， they were randomly divided into high， medium， and low dose Tangbikang granule groups （2.5， 1.25， 0.625 g·kg^-1·d^-1） and lipoic acid group （0.026 8 g·kg^-1·d^-1）， and the normal group was set up. The rats were administered continuously for 12 weeks after modeling. The blood glucose of rats was detected before intervention and at 4， 8， 12 weeks after intervention. At the 12^th week， motor nerve conduction velocity （MNCV）， sensory nerve conduction velocity （SNCV）， nerve blood flow velocity， mechanical pain threshold， and thermal pain threshold were detected. The sciatic nerve was taken for hematoxylin-eosin （HE） staining to observe the tissue morphology. The ultrastructure of the sciatic nerve was observed by transmission electron microscope. The expression levels of superoxide dismutase （SOD）， malondialdehyde （MDA）， interleukin-1β （IL-1β）， and tumor necrosis factor-α （TNF-α） in sciatic nerve were determined by enzyme-related immunosorbent assay （ELISA）. The mRNA expressions of AMPKα， AMPKβ， PGC-1α， and SIRT3 in sciatic nerve were determined by real-time polymerase chain reaction （Real-time PCR）. ResultCompared with the normal group， fasting blood glucose in the model group was increased at each time point （P<0.01）. The mechanical pain threshold was decreased （P<0.05）， and the incubation time of the hot plate was extended （P<0.01）. MNCV， SNCV， and nerve blood flow velocity decreased （P<0.05）. The expression level of SOD was decreased （P<0.01）. The expression levels of MDA， IL-1β， and TNF-α were increased （P<0.01）. The mRNA expression levels of AMPKα， AMPKβ， PGC-1α， and SIRT3 were decreased （P<0.01）. The structure of sciatic nerve fibers in the model group was loose， and the arrangement was disordered. The demyelination change was obvious. Compared with the model group， the fasting blood glucose of rats in the high dose Tangbikang granule group was decreased after the intervention of eight weeks and 12 weeks （P<0.01）. The mechanical pain threshold increased （P<0.05）. The incubation time of the hot plate was shortened （P<0.01）. MNCV， SNCV， and Flux increased （P<0.05）. The expression level of SOD was increased （P<0.01）. The expression levels of MDA， IL-1β， and TNF-α were decreased （P<0.01）. The mRNA expression levels of AMPKα， AMPKβ， PGC-1α， and SIRT3 were increased （P<0.01）. The sciatic nerve fibers in the high-dose Tangbikang granule group were tighter and more neatly arranged， with only a few demyelinating changes. The high， medium， and low dose Tangbikang granule groups showed a significant dose-effect trend. ConclusionTangbikang granules may improve sciatic nerve function in diabetic rats by regulating AMPK/PGC-1α/SIRT3 signaling pathway partly to inhibit oxidative stress.

Chemical cleaning and disinfection are crucial steps for eliminating infection in root canal treatment.However,irrigant selection or irrigation procedures are far from clear.The vapor lock effect in the apical region has yet to be solved,impeding irrigation efficacy and resulting in residual infections and compromised treatment outcomes.Additionally,ambiguous clinical indications for root canal medication and non-standardized dressing protocols must be clarified.Inappropriate intracanal medication may present side effects and jeopardize the therapeutic outcomes.Indeed,clinicians have been aware of these concerns for years.Based on the current evidence of studies,this article reviews the properties of various irrigants and intracanal medicaments and elucidates their effectiveness and interactions.The evolution of different kinetic irrigation methods,their effects,limitations,the paradigm shift,current indications,and effective operational procedures regarding intracanal medication are also discussed.This expert consensus aims to establish the clinical operation guidelines for root canal irrigation and a position statement on intracanal medication,thus facilitating a better understanding of infection control,standardizing clinical practice,and ultimately improving the success of endodontic therapy.

Objective To investigate the mechanism of abdominal massage for treating chronic fatigue syndrome(CFS).Methods Thirty clean-grade female Sprague-Dawley rats were randomly divided into the normal control,model control,and abdominal massage groups(n=10 rats per group).The CFS rat model was established through cold water swimming combined with the chronic restraint method in the model control and abdominal massage groups.The rats in the abdominal massage group were treated with the core techniques of Jingu zang-fu massage,namely layer press"Guanyuan"(CV4)for 8 min and Tuanmo"Zhongwan"(CV12)for 12 min as the primary intervention techniques,once a day for 14 consecutive days.The rats in the two control groups did not receive intervention;however,they were bound to the experimental bench when the experimental group was massaged.After the intervention,the indexes of the main organs of the hypothalamic-pituitary-adrenal(HPA)axis and hippocampal cell apoptosis in each group were measured.The morphology of hippocampal cells in each group was observed using Nissl staining of hippocampal tissue and transmission electron microscopy of hippocampal neurons.Results The index of each organ in the model control group was upregulated(P<0.01)compared to that of the normal control group.In contrast,the index of each organ in the abdominal massage group was downregulated(P<0.01)compared with that of the model control group.Compared to the normal control group,the index of each organ in the abdominal massage group was upregulated;however,the difference was not significant.Compared to the normal control group,the cell nuclei in the model control group were significantly consolidated,the nuclear membrane structure was ruptured,and the margins were irregular.Most of the cell morphology in the abdominal massage group was normal compared with that of the model control group,and a small number of nuclear membrane structures were unclear.Compared to the normal control group,the hippocampal neuronal cell in the other two groups was significantly damaged,and the hippocampal neuronal cell in the abdominal massage group was in good condition compared to the model control group.The degree of neuronal apoptosis in the model control group was significantly higher than that in the normal control group(P<0.01).The degree of neuronal apoptosis in the abdominal massage group decreased compared to that of the model control group(P<0.01),which was slightly higher than that in the normal control group but not significant.Conclusion Cold water swimming combined with chronic restraint can simulate CFS in rats,and abdominal massage can reduce the organ index of the hypothalamus,pituitary gland,and adrenal gland,increase hippocampal cell activity,reduce hippocampal tissue damage,inhibit hippocampal cell apoptosis,and maintain the normal physiological function of hippocampal neurons.

Prone position ventilation(PPV)is an essential therapeutic intervention for patients with refractory hypoxemic respiratory failure.The outbreak of coronavirus disease 2019(COVID-19)has further elevated the significance of PPV in clinical practice.Early enteral nutrition(EN)is considered a crucial measure for improving outcomes in critically ill patients.However,there remains considerable controversy regarding the implementation of EN during PPV.This review summarizes the research progress on the tolerance and safety of EN during PPV before and after the COVID-19 outbreak.It also highlights key strategies to enhance EN tolerance in prone-positioned patients,providing a clinical reference for improving patient management.

BACKGROUND: Stem cell-based transplantation therapy holds promise for peripheral nerve injury treatment, but adult availability is limited. A cell culture protocol utilizing a small-molecule cocktail effectively reprogrammed stem cells from apical papilla (SCAPs) into neural progenitor cells, subsequently differentiating into neuron-like cells. This study aims to evaluate neural-induced SCAPs, with and without small-molecule cocktail, for sciatic nerve repair potential. METHODS: A scaffold-free cell sheet technique was used to construct a three-dimensional cell sheet. Subsequently, this cell sheet was carefully rolled into a tube and seamlessly inserted into a collagen conduit, which was then transplanted into a 5 mm sciatic nerve injury rat model. Functional sciatic nerve regeneration was evaluated via toe spread test, walking track analysis and gastrocnemius muscle weight. Additionally, degree of sciatic nerve regeneration was determined based on total amount of myelinated fibers. RESULTS: Small-molecule cocktail induced SCAPs enhanced motor function recovery, evident in improved sciatic function index and gastrocnemius muscle retention. We also observed better host myelinated fiber retention than undifferentiated SCAPs or neural-induced SCAPs without small-molecule cocktail. However, clusters of neuron-like cell bodies (surrounded by sparse myelinated fibers) were found in all cell sheet-implanted groups in the implantation region. This suggests that while the implanted cells likely survived transplantation, integration was poor and would likely hinder longterm recovery by occupying the space needed for host nerve fibers to project through. CONCLUSION Neural-induced SCAPs with small-molecule cocktail demonstrated promising benefits for nerve repair; further research is needed to improve its integration and optimize its potential for long-term recovery.

ObjectiveThis study aims to investigate the therapeutic effect of Tangbikang granules（TBK） on type 2 diabetes mellitus （T2DM） complicated with non-alcoholic fatty liver disease （NAFLD） and to elucidate the underlying mechanism. MethodT2DM and NAFLD were induced in ZDF rats， which were then respectively treated （ig） with low-dose （0.625 g·kg^-1）， medium-dose （1.25 g·kg^-1）， and high-dose （2.5 g·kg^-1） TBK for 12 weeks. Fasting blood glucose （FBG） and body mass were recorded every 4 weeks during the treatment. One week before sampling， the feed intake of rats was detected， and after 12 h night fasting， oral glucose tolerance test （OGTT） was performed. The area under the curve （AUC） was used to evaluate glucose tolerance， and the homeostatic model assessment for insulin resistance （HOMA-IR） was calculated. Blood in abdominal aorta and liver were collected for determination of blood glucose and lipid metabolism indexes： Fasting serum insulin （FINS）， serum total cholesterol （TC）， triglyceride （TG）， low density lipoprotein cholesterol （LDL-C）， high density lipoprotein cholesterol （HDL-C）， and nonesterified fatty acids （NEFA）. The liver was weighed to calculate the liver index， and the liver tissue morphology was observed and analyzed based on hematoxylin-eosin （HE） staining and periodic acid-Schiff （PAS） staining. The protein levels of insulin receptor substrate （IRS）， phosphatidylinositol 3-kinase （PI3K）， protein kinase B （Akt） and phosphorylated IRS and Akt were detected by Western blotting. All data were analyzed by SPSS 20.0. ResultThe feed intake of the model group was higher than that in the normal group （P<0.01）， and the feed intake the administration groups was lower than that in the model group （P<0.05， P<0.01）. At the 8^th and 12^th week， the body mass in the model group was lower than that in the normal group （P<0.01）. Compared with the model group， TBK reduced FBG in a concentration-dependent manner. The blood glucose level in OGTT and AUC in the model group were higher/larger than those in the normal group （P<0.01）. The blood glucose value in OGTT was decreased in TBK groups and the metformin group compared with that in the model group， and AUC in the administration groups was significantly different from that in the model group （P<0.01）. The serum level of FINS and HOMA-IR in the model group were higher than those in the normal group （P<0.01）， and they were lower in the TBK groups than in the model group （P<0.01）. Serum levels of TG， TC， HDL-C， NEFA （P<0.05， P<0.01）， and LDL-C were higher in the model group than in the normal group. Serum levels of TG， TC， LDL-C， and NEFA in the TBK groups were lower than those in the model group， and the levels of TG， LDL-C， and NEFA in TBK groups were concentration-dependent （lowest levels in high-dose TBK group）. Compared with the model group， high-dose TBK significantly increased the level of HDL-C （P<0.05）. Liver index of the model group was higher than that in the normal group （P<0.01）. The liver index of the administration groups showed a decreasing trend with no significant difference from that in the model group. As for the HE staining result of liver， the model group had unclear structure of liver lobule， enlarged cells of different sizes， and obvious steatosis of hepatocytes. TBK of all doses alleviated liver injury， particularly the high dose. For the PAS staining， compared with the normal group， the model group demonstrated significant fat vacuoles and significant reduction in purplish red glycogen granules in the cytoplasm. The staining results of high- and medium-dose groups of TBK were more similar to the normal group. Western blot was used to detect the protein expression of liver tissue. The expression of PI3K protein， p-IRS1/IRS1， and p-Akt/Akt in the model group were lower than those in the normal group （P<0.01）， and they were higher in the high-dose TBK group than in the model group （P<0.01）. ConclusionTBK exerts therapeutic effect on T2DM combined with NAFLD in ZDF rats by activating the typical PI3K signaling pathway.

ObjectiveTo explore the mechanism of Tangbikang granules （TBK） against diabetic peripheral neuropathy （DPN） based on network pharmacology and in-vivo experiment. MethodThe active components in medicinals of TBK and their target genes were searched from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform （TCMSP）. The active components of the medicinals which are not included in TCMSP were searched from previous research. After the analysis of drug-likeness by SwissADME， the target genes of them were predicted with SwissTargetPrediction. DPN-related target genes were retrieved from GeneCards. The common targets of the disease and the prescription were the hub genes of TBK against DPN， which were uploaded to Metascape for Gene Ontology （GO） term enrichment and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analysis. High-sugar and high-fat diet and low-dose streptozotocin （STZ， ip） were employed to induce diabetes in rats， and then the model rats were respectively treated with low-dose （0.625 g·kg^-1）， medium-dose （1.25 g·kg^-1）， and high-dose （2.5 g·kg^-1） TBK for 12 weeks. Sensory nerve conduction velocity （SNCV） was evaluated. After hematoxylin and eosin （HE） staining， the sciatic nerve was observed under light microscope to examine the nerve damage. Real-time PCR was performed to detect the gene expression of adenosine monophosphate-activated protein kinase （AMPK） pathway-related targets in rat sciatic nerve， and Western blot to measure the protein expression of AMPK and phosphorylated （p）-AMPK in rat sciatic nerve. ResultThe main active components of TBK， such as quercetin， kaempferol， β-sitosterol， leech pteridine A， stigmasterol， and baicalein were screened out， mainly acting on interleukin-6 （IL-6）， tumor necrosis factor （TNF）， protein kinase B （Akt）， JUN， and HSP90AA1 and signaling pathways such as AMPK， nuclear factor-κB （NF-κB）， and Janus kinase/signal transducer and activator of transcription （JAK/STAT）. Molecular docking results showed that β-sitosterol and stigmasterol had high binding affinity with IL-6， TNF， JUN， and HSP90AA1. As for the animal experiment， compared with the normal group， model group had low SNCV of sciatic nerve （P<0.01）， disordered and loose myelinated nerve fibers with axonotmesis and demyelinization， low mRNA expression of AMPKα， AMPKβ， peroxisome proliferator-activated receptor γ coactivator-1α （PGC-1α）， Sirtuin 3 （SirT3）， mitochondrial transcription factor A （TFAM）， and low p-AMPK/AMPK ratio in sciatic nerve （P<0.05， P<0.01）. Compared with the model group， TBK of the three doses raised the SNCV （P<0.01）， restored nerve morphology and nerve compactness， and increased the mRNA expression of AMPKα， AMPKβ， PGC-1α， SirT3， and TFAM （P<0.05， P<0.01）. The ratio of p-AMPK/AMPK in the high-dose and medium-dose TBK groups was higher than that in the model group （P<0.01）， while the protein expression in the low-dose TBK group was insignificantly different from that in the model group. ConclusionTBK exerts therapeutic effect on DPN through multiple pathways and targets. The mechanism is that it activates and regulates AMPK/PGC-1α/SirT3 signaling， which lays a basis for further study of TBK in the treatment of DPN.