(Z)-3-Hexenol integrates drought and cold stress signaling by activating abscisic acid glucosylation in tea plants.

Cold and drought stresses severely limit crop production and can occur simultaneously. Although some transcription factors and hormones have been characterized in plants subjected each stress, the role of metabolites, especially volatiles, in response to cold and drought stress exposure is rarely studied due to lack of suitable models. Here, we established a model for studying the role of volatiles in tea (Camellia sinensis) plants experiencing cold and drought stresses simultaneously. Using this model, we showed that volatiles induced by cold stress promote drought tolerance in tea plants by mediating reactive oxygen species and stomatal conductance. Needle trap microextraction combined with GC-MS identified the volatiles involved in the crosstalk and showed that cold-induced (Z)-3-hexenol improved the drought tolerance of tea plants. In addition, silencing C. sinensis alcohol dehydrogenase 2 (CsADH2) led to reduced (Z)-3-hexenol production and significantly reduced drought tolerance in response to simultaneous cold and drought stress. Transcriptome and metabolite analyses, together with plant hormone comparison and abscisic acid (ABA) biosynthesis pathway inhibition experiments, further confirmed the roles of ABA in (Z)-3-hexenol-induced drought tolerance of tea plants. (Z)-3-Hexenol application and gene silencing results supported the hypothesis that (Z)-3-hexenol plays a role in the integration of cold and drought tolerance by stimulating the dual-function glucosyltransferase UGT85A53, thereby altering ABA homeostasis in tea plants. Overall, we present a model for studying the roles of metabolites in plants under multiple stresses and reveal the roles of volatiles in integrating cold and drought stresses in plants.

Prognostic factors for residual symptoms following percutaneous endoscopic lumbar discectomy.

To explore the risk factors for residual symptoms following percutaneous endoscopic lumbar discectomy (PELD). A retrospective case-controlled study. From January 2015 to December 2020, consecutive patients who underwent PELD for lumbar disc herniation (LDH) in our department were retrospectively studied. All the patients were followed-up at least two years. Residual symptoms were analyzed for association with baseline data, clinical feature, physical examination, and radiographic characteristics, which were used to detected the risk factors. A total of 339 patients were included in this study, with a mean follow-up of 28.7 ± 3.6 months. Of the enrolled patients, 90 (26.5%) patients experienced residual low back pain (LBP), and 76 (22.4%) patients experienced leg numbness (LN). Multivariate logistic regression analysis revealed that intervertebral disc calcification on CT scans (odd ratio, 0.480; 95% confidence interval: 0.247 ~ 0.932; P < 0.05) was independent risk factor for postoperative residual LBP with odd ratio and longer symptom duration was risk factor for postoperative residual LN (odd ratio, 2.231; 95% confidence interval:1.066 ~ 4.671; P < 0.05). Residual symptoms following transforaminal endoscopic surgery are quite prevalent. Intervertebral disc calcification is a protective factor for residual low back pain, and a longer symptom duration is a risk factor for residual leg numbness.

Retrieval analysis of PEEK rods pedicle screw system: three cases analysis.

PURPOSE: To analyze the characteristics of PEEK rods retrieved in vivo, specifically their wear and deformation, biodegradability, histocompatibility, and mechanical properties. METHOD: Six PEEK rods were retrieved from revision surgeries along with periprosthetic tissue. The retrieved PEEK rods were evaluated for surface damage and internal changes using Micro-CT, while light and electron microscopy were utilized to determine any histological changes in periprosthetic tissues. Patient history was gathered from medical records. Two intact and retrieved PEEK rods were used for fatigue testing analysis by sinusoidal load to the spinal construct. RESULTS: All implants showed evidence of plastic deformation around the screw-rod interface, while the inner structure of PEEK rods appeared unchanged with no visible voids or cracks. Examining images captured through light and electron microscopy indicated that phagocytosis of macrophages around PEEK rods was less severe in comparison to the screw-rod interface. The results of an energy spectrum analysis suggested that the distribution of tissue elements around PEEK rods did not differ significantly from normal tissue. During fatigue testing, it was found that the retrieved PEEK rods cracked after 1.36 million tests, whereas the intact PEEK rods completed 5 million fatigue tests without any failure. CONCLUSION: PEEK rods demonstrate satisfactory biocompatibility, corrosion resistance, chemical stability, and mechanical properties. Nevertheless, it is observed that the indentation at the junction between the nut and the rod exhibits relatively weak strength, making it susceptible to breakage. As a precautionary measure, it is recommended to secure the nut with a counter wrench, applying the preset torque to prevent overtightening.

Eugenol functions as a signal mediating cold and drought tolerance via UGT71A59-mediated glucosylation in tea plants.

Cold and drought stress are the most critical stresses encountered by crops and occur simultaneously under field conditions. However, it is unclear whether volatiles contribute to both cold and drought tolerance, and if so, by what mechanisms they act. Here, we show that airborne eugenol can be taken up by the tea (Camellia sinensis) plant and metabolized into glycosides, thus enhancing cold and drought tolerance of tea plants. A uridine diphosphate (UDP)-glucosyltransferase, UGT71A59, was discovered, whose expression is strongly induced by multiple abiotic stresses. UGT71A59 specifically catalyzes glucosylation of eugenol glucoside in vitro and in vivo. Suppression of UGT71A59 expression in tea reduced the accumulation of eugenol glucoside, lowered reactive oxygen species (ROS) scavenging capacity, and ultimately impaired cold and drought stress tolerance. Exposure to airborne eugenol triggered a marked increase in UGT71A59 expression, eugenol glucoside accumulation, and cold tolerance by modulating ROS accumulation and CBF1 expression. It also promoted drought tolerance by altering abscisic acid homeostasis and stomatal closure. CBF1 and CBF3 play positive roles in eugenol-induced cold tolerance and CBF2 may be a negative regulator of eugenol-induced cold tolerance in tea plants. These results provide evidence that eugenol functions as a signal in cold and drought tolerance regulation and shed new light on the biological functions of volatiles in the response to multiple abiotic stresses in plants.

Salicylic acid carboxyl glucosyltransferase UGT87E7 regulates disease resistance in Camellia sinensis.

Plant immune response following pathogenic infection is regulated by plant hormones, and salicylic acid (SA) and its sugar conjugates play important roles in establishing basal resistance. Here, the important pathogen Pseudopestalotiopsis camelliae-sinensis (Pcs) was isolated from tea gray blight, one of the most destructive diseases in tea plantations. Transcriptomic analysis led to the discovery of the putative Camellia sinensis UDP-glucosyltransferase CsUGT87E7 whose expression was significantly induced by SA application and Pcs infection. Recombinant CsUGT87E7 glucosylates SA with a Km value of 12 µM to form SA glucose ester (SGE). Downregulation reduced the accumulation of SGE, and CsUGT87E7-silenced tea plants exhibited greater susceptibility to pathogen infection than control plants. Similarly, CsUGT87E7-silenced tea leaves accumulated significantly less SA after infection and showed reduced expression of pathogenesis-related genes. These results suggest that CsUGT87E7 is an SA carboxyl glucosyltransferase that plays a positive role in plant disease resistance by modulating SA homeostasis through a mechanism distinct from that described in Arabidopsis (Arabidopsis thaliana). This study provides insight into the mechanisms of SA metabolism and highlights the role of SGE in the modulation of plant disease resistance.

Comparative analysis of patient-reported outcomes after percutaneous endoscopic lumbar discectomy between transforaminal and interlaminar approach: a minimum two year follow-up.

PURPOSE: Percutaneous endoscopic lumbar discectomy has been increasingly used in the treatment of lumbar disc herniation. However, there is no consensus on which method would be more effective between the transforaminal and interlaminar approach. OBJECTIVE: To compare clinical outcomes, patient satisfaction rate, reoperation rate, and residual symptoms between percutaneous endoscopic transforaminal discectomy (PETD) and percutaneous endoscopic interlaminar discectomy (PEID). STUDY DESIGN: A comparative, retrospective, controlled trial. SETTING: The study was conducted at the Department of Orthopaedics at a local hospital. METHODS: From January 2015 to September 2020, consecutive patients who underwent PETD or PEID treatment for lumbar disk herniation (LDH) at the L5/S1 level in our department were retrospectively collected. Baseline data including age, gender, body mass index (BMI), smoking status, alcohol drinking, clinical symptoms, physical examination, and radiographic characteristics were documented. During the two to three year follow-up periods, patients were evaluated clinically, including clinical outcomes assessed by the visual analog score (VAS), patient satisfaction rates assessed by the North American Spine Society patient satisfaction index (PSI), recurrent rate, and residual symptoms. RESULTS: A total of 113 patients with PELD in our department were included in the current study, with 65 patients in the PETD group and 48 in the PEID group. Demographic characteristics including age, gender, height, BMI, cigarette smoking, alcohol consumption status, and diabetes did not show any significant difference between the PETD and PEID groups. The VAS scores of the two groups were similar preoperatively, but the postoperative VAS score of the PEID group was lower than that of the PETD group. There were 90.8% of patients in the PETD group who were satisfied with the operation compared to 97.9% in the PEID group. The recurrence rate did not differ between groups, with three patients in both groups. Regarding residual symptoms, there were more patients in the PETD group who reported low back pain during the follow-up periods. LIMITATION: The main limitations are that all patients were operated by the same surgical team from the same site, and there was a lack of multicenter data. CONCLUSION: Both PETD and PEID have satisfactory patient-reported outcomes for treating LDH. The PEID procedure results in fewer low back pain residual symptoms than the PELD procedure.

Conservative surgery with microwave ablation for recurrent bone tumor in the extremities: a single-center study.

BACKGROUND: Surgical treatment for recurrent bone tumors in the extremities still presents a challenge. This study was designed to evaluate the clinical value of microwave ablation in the treatment of recurrent bone tumors. METHODS: We present 15 patients who underwent microwave ablation for recurrent bone tumors during the last 7 years. The following parameters were analyzed for outcome evaluation: general condition, surgical complications, local disease control, overall survival, and functional score measured using the Musculoskeletal Tumor Society (MSTS) 93 scoring system. RESULTS: Percutaneous microwave ablation in one patient with osteoid osteoma and another with bone metastasis resulted in postoperative pain relief. Thirteen patients received intraoperative microwave ablation before curettage or resection, including those with giant cell tumors of bone (6), chondroblastoma (2), osteosarcoma (2), undifferentiated sarcoma (1), and bone metastases (2). All patients achieved reasonable local tumor control in the mean follow-up of 29.9 months. The functional score was 24.1 for the 15 patients 6 months after the operation. Four patients had tumor metastasis and died, whereas 3 patients with tumors survived, and the remaining 8 patients without the disease survived. CONCLUSIONS: Microwave ablation represents an optional method for local control in treating recurrent bone tumors in the extremities.

Mechanical response of surface wettability of Janus porous membrane and its application in oil-water separation.

Smart surfaces with switchable wettability are widely studied for environmental application. Although a large number of stimulation routes provide broad prospects for the development of smart surfaces, achieving high sensitivity, fast response and recovery, simple operation, security and good stability is still challenging. Herein, a Janus membrane via electrospinning, chemical bath deposition and heat treatment is constructed. By using the hydrophilic ZIF-L nanosheet to functionalize the hydrophobic thermoplastic polyurethane (TPU) substrate, a smart surface utilizes the ZIF-L crack induced by strain in the hydrophilic layer to control surface wettability is obtained. In the range of 0%-100% strain, the wettability of the smart surface presents an obvious change with stretching, and water contact angle of the surface shows a monotonic increase with a maximum tuning range from 47° to 114°. Due to local fusion of the TPU microfibers and good binding between the ZIF-L layer and the TPU substrate after heat treatment, the prepared Janus membrane exhibits consistent and symmetrical hydrophilic-hydrophobic-hydrophilic transition curves in 50 stretching-releasing cycles. Thanks to the porous and asymmetric architecture, the membrane shows good oil-water separation performance, and the separation flux increases with the increase of strain, while the separation efficiency is always higher than 98%. Because of the excellent structural stability, the robust membrane with 100% strain maintains its oil-water separation property for 50 stretching-releasing cycles. This study provides a new perspective for the development of smart material with stimuli responsive surface for oily wastewater purification.

Knowledge, attitude and application towards fast track surgery among operating room paramedics: a cross-sectional study.

BACKGROUND: Fast track surgery has shown its effectiveness to accelerate recovery and gained acceptance in many operations. However, data for paramedics using fast track surgery are limited in China. The aims of our study are to evaluate the knowledge, attitude and application status of fast track surgery in paramedics and to provide suggestions for the better application of fast track surgery. METHODS: Two Hundred Ninety-one operating room paramedics were investigated by simple random sampling from October 20 to December 20, 2019 time. A self-reported questionnaire was used to collect data with five dimensions: demographic data, cognitive level, knowledge, attitude and application of fast track surgery. Data were analyzed using qualitative and quantitative methods. RESULTS: 19.93% of participants never heard fast track surgery and only 3.32% of participants were very familiar with it. Gender (0.702, 95% CI 0.109-1.294), technical title (0.342, 95% CI 0.126-0.558) and awareness of the concept of fast track surgery (0.471, 95% CI 0.165-0.776) had a correlation with the knowledge level of paramedics towards fast track surgery. In terms of attitude towards fast track surgery, gender (- 1.944, 95% CI -3.830- -0.058), age (0.303, 95% CI 0.021-0.585) and knowledge score of fast track surgery (0.426, 95% CI 0.014-0.838) are related. Half of the paramedics believe the most difficult problem in the application of fast track surgery was the lack of multi-team communication and cooperation. CONCLUSION: The knowledge of fast track surgery among paramedics in Wuhan is poor, and some paramedics have a negative attitude towards it. As the attitude is positively correlated with the knowledge, it is necessary to improve the knowledge level of fast track surgery among paramedics in Wuhan.

Prolyl isomerization of FAAP20 catalyzed by PIN1 regulates the Fanconi anemia pathway.

The Fanconi Anemia (FA) pathway is a multi-step DNA repair process at stalled replication forks in response to DNA interstrand cross-links (ICLs). Pathological mutation of key FA genes leads to the inherited disorder FA, characterized by progressive bone marrow failure and cancer predisposition. The study of FA is of great importance not only to children suffering from FA but also as a model to study cancer pathogenesis in light of genome instability among the general population. FANCD2 monoubiquitination by the FA core complex is an essential gateway that connects upstream DNA damage signaling to enzymatic steps of repair. FAAP20 is a key component of the FA core complex, and regulated proteolysis of FAAP20 mediated by the ubiquitin E3 ligase SCFFBW7 is critical for maintaining the integrity of the FA complex and FA pathway signaling. However, upstream regulatory mechanisms that govern this signaling remain unclear. Here, we show that PIN1, a phosphorylation-specific prolyl isomerase, regulates the integrity of the FA core complex, thus FA pathway activation. We demonstrate that PIN1 catalyzes cis-trans isomerization of the FAAP20 pSer48-Pro49 motif and promotes FAAP20 stability. Mechanistically, PIN1-induced conformational change of FAAP20 enhances its interaction with the PP2A phosphatase to counteract SCFFBW7-dependent proteolytic signaling at the phosphorylated degron motif. Accordingly, PIN1 deficiency impairs FANCD2 activation and the DNA ICL repair process. Together, our study establishes PIN1-dependent prolyl isomerization as a new regulator of the FA pathway and genomic integrity.

Safety and efficacy of negative pressure wound therapy in treating deep surgical site infection after lumbar surgery.

PURPOSE: To evaluate the efficacy and safety of negative pressure wound therapy (NPWT) for post-operative deep surgical site infection (SSI) after posterior instrumented spinal surgery. METHODS: We retrospectively compared the clinical outcomes of NPWT with standard debridement for deep SSI after posterior instrumented spinal surgery from 2012 to 2020 in our department. The primary outcomes were peri-operative characteristics including positive organism results, duration of fever, and visual analogue scale (VAS) pain scores three days after re-operation. The secondary outcomes were post-operative characteristics including implant infection recurrence, implant retention rate, duration of hospitalization, and VAS at discharge. Pearson's chi-squared analysis (categorical) and Student's t test (continuous) were used to determine the differences. RESULTS: Thirty-four patients were included, of which 19 underwent NPWT, and 15 underwent standard debridement. Patients in the NPWT group all significantly improved primary outcomes including duration of fever after re-operation (0.95 ± 1.13 vs 4.07 ± 5.35, P = 0.001), positive organism results (14 of 19 vs 2 of 15, P < 0.01), and VAS at 3 days after re-operation (2.58 ± 0.69 vs 3.40 ± 1.06, P < 0.05). Patients in NPWT group exhibited significant decrease in implant infection recurrence (0 of 19 vs 5 of 15, P < 0.01), implant retention rate (19 of 19 vs 10 of 15, P < 0.01), duration of hospitalization (27.74 ± 10.95 vs 37.67 ± 13.67, P < 0.01). CONCLUSIONS: NPWT is a feasible and safe treatment option for deep SSI after posterior instrumented spinal surgery.

Herbivore-induced DMNT catalyzed by CYP82D47 plays an important role in the induction of JA-dependent herbivore resistance of neighboring tea plants.

Herbivore-induced plant volatiles play important ecological roles in defense against stresses. However, if and which volatile(s) are involved in the plant-plant communication in response to herbivorous insects in tea plants remains unknown. Here, plant-plant communication experiments confirm that volatiles emitted from insects-attacked tea plants can trigger plant resistance and reduce the risk of herbivore damage by inducing jasmonic acid (JA) accumulation in neighboring plants. The emission of six compounds was significantly induced by geometrid Ectropis obliqua, one of the most common pests of the tea plant in China. Among them, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) could induce the accumulation of JA and thus promotes the resistance of neighboring intact plants to herbivorous insects. CsCYP82D47 was identified for the first time as a P450 enzyme, which catalyzes the final step in the biosynthesis of DMNT from (E)-nerolidol. Down-regulation of CsCYP82D47 in tea plants resulted in a reduced accumulation of DMNT and significantly reduced the release of DMNT in response to the feeding of herbivorous insects. The first evidence for plant-plant communication in response to herbivores in tea plants will help to understand how plants respond to volatile cues in response to herbivores and provide new insight into the role(s) of DMNT in tea plants.

Sesquiterpene glucosylation mediated by glucosyltransferase UGT91Q2 is involved in the modulation of cold stress tolerance in tea plants.

Plants produce and emit terpenes, including sesquiterpenes, during growth and development, which serve different functions in plants. The sesquiterpene nerolidol has health-promoting properties and adds a floral scent to plants. However, the glycosylation mechanism of nerolidol and its biological roles in plants remained unknown. Sesquiterpene UDP-glucosyltransferases were selected by using metabolites-genes correlation analysis, and its roles in response to cold stress were studied. We discovered the first plant UGT (UGT91Q2) in tea plant, whose expression is strongly induced by cold stress and which specifically catalyzes the glucosylation of nerolidol. The accumulation of nerolidol glucoside was consistent with the expression level of UGT91Q2 in response to cold stress, as well as in different tea cultivars. The reactive oxygen species (ROS) scavenging capacity of nerolidol glucoside was significantly higher than that of free nerolidol. Down-regulation of UGT91Q2 resulted in reduced accumulation of nerolidol glucoside, ROS scavenging capacity and tea plant cold tolerance. Tea plants absorbed airborne nerolidol and converted it to its glucoside, subsequently enhancing tea plant cold stress tolerance. Nerolidol plays a role in response to cold stress as well as in triggering plant-plant communication in response to cold stress. Our findings reveal previously unidentified roles of volatiles in response to abiotic stress in plants.

Scenarios of Genes-to-Terpenoids Network Led to the Identification of a Novel α/ß-Farnesene/ß-Ocimene Synthase in Camellia sinensis.

Terpenoids play vital roles in tea aroma quality and plants defense performance determination, whereas the scenarios of genes to metabolites of terpenes pathway remain uninvestigated in tea plants. Here, we report the use of an integrated approach combining metabolites, target gene transcripts and function analyses to reveal a gene-to-terpene network in tea plants. Forty-one terpenes including 26 monoterpenes, 14 sesquiterpenes and one triterpene were detected and 82 terpenes related genes were identified from five tissues of tea plants. Pearson correlation analysis resulted in genes to metabolites network. One terpene synthases whose expression positively correlated with farnesene were selected and its function was confirmed involved in the biosynthesis of α-farnesene, ß-ocimene and ß-farnesene, a very important and conserved alarm pheromone in response to aphids by both in vitro enzymatic assay in planta function analysis. In summary, we provided the first reliable gene-to-terpene network for novel genes discovery.

Induction of priming by cold stress via inducible volatile cues in neighboring tea plants.

Plants have evolved sophisticated defense mechanisms to overcome their sessile nature. However, if and how volatiles from cold-stressed plants can trigger interplant communication is still unknown. Here, we provide the first evidence for interplant communication via inducible volatiles in cold stress. The volatiles, including nerolidol, geraniol, linalool, and methyl salicylate, emitted from cold-stressed tea plants play key role(s) in priming cold tolerance of their neighbors via a C-repeat-binding factors-dependent pathway. The knowledge will help us to understand how plants respond to volatile cues in cold stress and agricultural ecosystems.

PCNA-Dependent Cleavage and Degradation of SDE2 Regulates Response to Replication Stress.

Maintaining genomic integrity during DNA replication is essential for cellular survival and for preventing tumorigenesis. Proliferating cell nuclear antigen (PCNA) functions as a processivity factor for DNA replication, and posttranslational modification of PCNA plays a key role in coordinating DNA repair against replication-blocking lesions by providing a platform to recruit factors required for DNA repair and cell cycle control. Here, we identify human SDE2 as a new genome surveillance factor regulated by PCNA interaction. SDE2 contains an N-terminal ubiquitin-like (UBL) fold, which is cleaved at a diglycine motif via a PCNA-interacting peptide (PIP) box and deubiquitinating enzyme activity. The cleaved SDE2 is required for negatively regulating ultraviolet damage-inducible PCNA monoubiquitination and counteracting replication stress. The cleaved SDE2 products need to be degraded by the CRL4CDT2 ubiquitin E3 ligase in a cell cycle- and DNA damage-dependent manner, and failure to degrade SDE2 impairs S phase progression and cellular survival. Collectively, this study uncovers a new role for CRL4CDT2 in protecting genomic integrity against replication stress via regulated proteolysis of PCNA-associated SDE2 and provides insights into how an integrated UBL domain within linear polypeptide sequence controls protein stability and function.

Inhibition of cancer cell migration and invasion through suppressing the Wnt1-mediating signal pathway by G-quadruplex structure stabilizers.

WNT1 encodes a multifunctional signaling glycoprotein that is highly expressed in several malignant tumors. Patients with Wnt1-positive cancer are usually related to advanced metastasis. Here, we found that a stretch of G-rich sequences located at the WNT1 promoter region is capable of forming G-quadruplex structures. The addition of G-quadruplex structure stabilizers, BMVC and BMVC4, raises the melting temperature of the oligonucleotide formed by the WNT1 promoter G-rich sequences. Significantly, the expression of WNT1 was repressed by BMVC or BMVC4 in a G-quadruplex-dependent manner, suggesting that they can be used to modulate WNT1 expression. The role of G-quadruplex stabilizers on Wnt1-mediated cancer migration and invasion was further analyzed. The protein levels of ß-catenin, a mediator of the Wnt-mediated signaling pathway, and the downstream targets MMP7 and survivin were down-regulated upon BMVC or BMVC4 treatments. Moreover, the migration and invasion activities of cancer cells were inhibited by BMVC and BMVC4, and the inhibitory effects can be reversed by WNT1-overexpression. Thus the Wnt1 expression and its downstream signaling pathways can be regulated through the G-quadruplex sequences located at its promoter region. These findings provide a novel approach for future drug development to inhibit migration and invasion of cancer cells.

Bruton's tyrosine kinase regulates TLR9 but not TLR7 signaling in human plasmacytoid dendritic cells.

Plasmacytoid dendritic cells (PDCs) represent a key cell type for both innate and adaptive immunity. PDCs express both TLR7 and TLR9 and the recognition of nucleic acids by these two receptors triggers the production of a large amount of type-I IFN and the induction of PDC maturation into APCs. This unique feature of PDCs is at the basis of clinical development of both TLR7 and TLR9 agonists for infectious diseases, allergy, cancer, and asthma. However, TLR7 and TLR9 recognition of self-nucleic acids is linked to many autoimmune diseases including lupus, and a better understanding of the signaling pathways of these two receptors in PDCs is thus important. We have identified Bruton's tyrosine kinase (Btk) as an important player for TLR9 but not TLR7 signaling in human PDCs. Blocking Btk using a specific inhibitor leads to the reduction of all TLR9-induced responses in PDCs, including cytokine production and expression of costimulatory molecules, while this has no impact on the TLR7 response. This identifies Btk as a key molecule in TLR9 signaling in PDCs and is the first demonstration that the TLR7 and TLR9 pathways can be dissociated in human PDCs.

Hydrostatic pressure effect on micro air bubbles deposited on surfaces with a retreating tip.

The effect of hydrostatic pressure on 6 µL air bubbles formed on micropillar structured PDMS and silicone surfaces using a 2 mm diameter stainless steel tip retreated at 1 mm/s was investigated. Dimensional analysis of the tip retraction process showed the experiments to be conducted in the condition where fluid inertial forces are comparable in magnitude with surface tension forces, while viscous forces were lower. Larger bubbles could be left behind on the structured PDMS surface. For hydrostatic pressures in excess of 20 mm H2O (196 Pa), the volume of bubble deposited was found to decrease progressively with pressure increase. The differences in width of the deposited bubbles (in contact with the substrate) were significant at any particular pressure but marginal in height. The attainable height before rupture reduced with pressure increase, thereby accounting for the reducing dispensed volume characteristic. On structured PDMS, the gaseous bridge width (in contact with the substrate) was invariant with tip retraction, while on silicone it was initially reducing before becoming invariant in the lead up to rupture. With silicone, hence, reductions in the contact width and height were both responsible for reduced volumes with pressure increase. Increased hydrostatic pressure was also found to restrict the growth in contact width on silicone during the stage when air was injected in through the tip. The ability to effect bubble size in such a simple manner may already be harnessed in nature and suggests possibilities in technological applications.