Visceral Adipose Tissue Depth as a Novel Predictor for Gestational Diabetes Mellitus: A Comprehensive Meta-Analysis and Systematic Review.

Background and Objectives: The escalating prevalence of gestational diabetes mellitus (GDM) and the limitations associated with utilizing body mass index (BMI) as a predictive measure underscore the imperative need for identifying an optimal early pregnancy predictor. Such a predictor not only mitigates the risk of GDM but also allows for timely implementation of interventions. Materials and Methods: This meta-analysis aimed to explore the association between visceral adipose tissue (VAT) depth and the risk of GDM. A thorough search of PubMed, Embase, and Web of Science databases was conducted up to 30 September 2023. The analysis employed a random-effects model to assess the relationship between VAT depth and the likelihood of GDM. Results: The inclusion criteria encompassed seven studies involving 1315 women, including 225 diagnosed with GDM. Significantly lower VAT depth was observed in the non-GDM group in comparison to the GDM group (Standardized Mean Difference [SMD]: 0.84; 95% Confidence Interval [CI]: 0.52-1.15; p < 0.001). Substantial statistical heterogeneity was noted among studies (I2 = 72.88%, p = 0.001). Through meticulous sensitivity and subgroup analyses, the source of heterogeneity was identified and thoroughly discussed. Subgroup analyses suggest that different GDM diagnostic criteria and VAT definitions all indicate higher VAT depth in GDM patients during early pregnancy. Conclusions: Our findings propose that, during the first trimester, GDM patients exhibit higher VAT depth compared to non-GDM women, highlighting VAT depth as a potential predictive factor for GDM in early pregnancy. This study contributes valuable evidence to the growing body of knowledge surrounding novel predictors for GDM, emphasizing the importance of early intervention strategies.

A novel web-based dynamic prognostic nomogram for gastric signet ring cell carcinoma: a multicenter population-based study.

Background: Gastric signet ring cell carcinoma (GSRCC) is a rare and highly malignant disease with a poor prognosis. To assess the overall survival (OS) and cancer-specific survival (CSS) of patients with GSRCC, prognostic nomograms were developed and validated using common clinical factors. Methods: This retrospective cohort study included patients diagnosed with GSRCC between 2011 and 2018 from the National Cancer Center (n = 1453) and SEER databases (n = 2745). Prognostic nomograms were established by identifying independent prognostic factors using univariate and multivariate Cox regression analyses. The calibration curve and C-index were used to assess the predictions. The clinical usefulness of the survival prediction model was further evaluated using the DCA and ROC curves. The models were internally validated in the training cohort and externally validated in the validation cohort. Two web servers were created to make the nomogram easier to use. Results: Patients with GSRCC were divided into training (n = 2938) and validation (n = 1260) cohorts. The nomograms incorporated six predictors: age, race, tumor site, tumor size, N stage, T stage, and AJCC stage. Excellent agreement was observed between the internal and exterior calibration plots for the GSRCC survival estimates. The C-index and area under the ROC curve were roughly greater than 0.7. Both nomograms had adequate clinical efficacy, as demonstrated by the DCA plots. Furthermore, we developed a dynamic web application utilizing the constructed nomograms available at https://jiangyujuan.shinyapps.io/OS-nomogram/ and https://jiangyujuan.shinyapps.io/DynNomapp-DFS/. Conclusion: We developed web-based dynamic nomograms utilizing six independent prognostic variables that assist physicians in estimating the OS and CSS of patients with GSRCC.

NIR Light-Fuse Drug-Free Photothermal Armor-Piercing Microcapsule for Femoral Vein Thrombosis Therapy.

Acute thrombosis and its complications are leading global causes of disability and death. Existing thrombolytic drugs, such as alteplase and urokinase (UK), carry a significant bleeding risk during clinical treatments. Thus, the development of a novel thrombolysis strategy is of utmost urgency. Based on the previous work, the hollow structure of microcapsules (MC) is fabricated. Subsequently, armor-piercing MC, known as Fucoidan/S-Nitrosoglutathione/Melanin@MC (FGM@MC) is obtained, using a layer-by-layer (LBL) self-assembly method. Utilizing near-infrared (NIR) light as a trigger, the FGM@MC demonstrated photothermal thrombolysis at the site of thrombus due to its stable and outstanding photothermal properties. Simultaneously, photothermal stimulation leads to the release of a significant amount of nitric oxide from the FGM@MC, resulting in cavitation effects for mechanical thrombolysis. In vivo experiments confirmed the stable release of nitric oxide under NIR light irradiation. Treatment of femoral vein thrombosis in rats revealed that the thrombolytic effectiveness of FGM@MC+NIR (53.71%) is comparable to that of UK (59.70%). Notably, FGM@MC does not interfere with the coagulation function of rats and exhibits a favorable safety profile. In conclusion, this study demonstrates that the drug-free armor-piercing microcapsule has significant potential in the treatment of thrombosis, offering a safe and effective alternative to traditional thrombolytic therapies.

Transformable Magnetic Liquid-Metal Nanoplatform for Intracellular Drug Delivery and MR Imaging-Guided Microwave Thermochemotherapy.

Improved techniques for the administration of chemotherapeutic drugs are required to enhance tumor therapy efficacy and reduce the side effects of chemotherapy due to insufficient targeting and limited intratumoral drug release. Controlled drug delivery systems combined with thermotherapy are expected to play an important role in personalized tumor therapy. Herein, a novel microwave-responsive transformable magnetic liquid-metal (MLM) nanoplatform is designed for effective endosomal escape that facilitates intracellular drug delivery and enhanced anticancer therapy. The MLM nanoplatform exhibits a sensitive magnetic resonance imaging function for imaging-guided therapy and brilliant synergistic effects of chemotherapy with microwave thermal therapy to kill tumor cells. Once endocytosed by targeted tumor cells, the deep penetration of microwave energy can be absorbed by the MLM nanoplatform to convert heat and reactive oxygen species, which induces the shape transformation from nanospheres to large rods, resulting in the physical disruption of the endosomal membrane for intracellular drug release. Furthermore, the MLM nanoplatform synergistic therapy could activate immunomodulatory effects by M1 macrophage polarization and T cell infiltration, thus inhibiting tumor growth and lung metastasis. This work based on microwave-driven transformable magnetic liquid-metal nanoplatform provides novel ways to precisely control drug delivery and high-efficiency cancer therapy.

All-in-One Self-Powered Microneedle Device for Accelerating Infected Diabetic Wound Repair.

Diabetic wound healing remains a significant clinical challenge due to the complex microenvironment and attenuated endogenous electric field. Herein, a novel all-in-one self-powered microneedle device (termed TZ@mMN-TENG) is developed by combining the multifunctional microneedle carried tannin@ZnO microparticles (TZ@mMN) with the self-powered triboelectric nanogenerator (TENG). In addition to the delivery of tannin and Zn2+ , TZ@mMN also effectively conducts electrical stimulation (ES) to infected diabetic wounds. As a self-powered device, the TENG can convert biomechanical motion into exogenous ES to accelerate the infected diabetic wound healing. In vitro experiment demonstrated that TZ@mMN shows excellent conductive, high antioxidant ability, and effective antibacterial properties against both Staphylococcus aureus and Escherichia coli (>99% antibacterial rates). Besides, the TZ@mMN-TENG can effectively promote cell proliferation and migration. In the diabetic rat full-thickness skin wound model infected with Staphylococcus aureus, the TZ@mMN-TENG can eliminate bacteria, accelerate epidermal growth (regenerative epidermis: ≈303.3 ± 19.1 µm), enhance collagen deposition, inhibit inflammation (lower TNF-α and IL-6 expression), and promote angiogenesis (higher CD31 and VEGF expression) to accelerate infected wound repair. Overall, the TZ@mMN-TENG provides a promising strategy for clinical application in diabetic wound repair.

Assembly of Metal-Phenolic Networks onto Microbubbles for One-Step Generation of Functional Microcapsules.

The one-step assembly of metal-phenolic networks (MPNs) onto particle templates can enable the facile, rapid, and robust construction of hollow microcapsules. However, the required template removal step may affect the refilling of functional species in the hollow interior space or the in situ encapsulation of guest molecules during the formation of the shells. Herein, a simple strategy for the one-step generation of functional MPNs microcapsules is proposed. This method uses bovine serum albumin microbubbles (BSA MBs) as soft templates and carriers, enabling the efficient pre-encapsulation of guest species by leveraging the coordination assembly of tannic acid (TA) and FeIII ions. The addition of TA and FeIII induces a change in the protein conformation of BSA MBs and produces semipermeable capsule shells, which allow gas to escape from the MBs without template removal. The MBs-templated strategy can produce highly biocompatible capsules with controllable structure and size, and it is applicable to produce other MPNs systems like BSA-TA-CuII and BSA-TA-NiII . Finally, those MBs-templated MPNs capsules can be further functionalized or modified for the loading of magnetic nanoparticles and the pre-encapsulation of model molecules through covalence or physical adsorption, exhibiting great promise in biomedical applications.

Impact of Removal of Lymph Nodes on Survival in Stage I-III Gastric Signet-Ring Cell Cancer: The More, the Better?

BACKGROUND: There is an ongoing debate over the prognostic value of the number of examined lymph nodes (ELNs) in cases of gastric signet-ring cell cancer (GSRCC). In this study, we sought to evaluate the correlation between the number of ELNs and the prognosis of GSRCC and identify the optimal number of ELNs. METHODS: A total of 1020 patients diagnosed with GSRCC between 2011 and 2018 in the National Cancer Center database were identified. Clinicopathological characteristics were retrospectively collected, and optimal cutoff values of ELNs were calculated by using X-tile. The impact of different ELNs on overall survival (OS) was compared by using Kaplan-Meier curves. We used univariate and multivariate Cox and subgroup analyses to explore the relationship between ELNs and OS. Furthermore, nonlinear correlations were investigated by using restricted cubic splines (RCSs). RESULTS: X-tile showed that the optimal cutoff value of ELNs was 22. The 5-year OS was higher for patients with ELNs > 22 (vs. ELNs ≤ 22, 66.9% vs. 74.9%, P = 0.026). Multivariate Cox analyses showed that high ELNs were associated with superior OS (hazard ratio = 0.56, 95% confidence interval 0.43-0.74, P < 0.001). In subgroup analyses, the significant association between tumor size > 4 cm, and TNM III stage was still observed. The RCS regression model showed a U-shaped dose-response nonlinear relationship between ELNs and OS; the inflection point, as well as the lowest risk points, corresponded to 44-52 ELNs. CONCLUSIONS: A U-shaped, nonlinear correlation with inflection points of 44-52 ELNs between ELNs and prognosis in GSRCC was identified.

Potentilla parvifolia strongly influenced soil microbial community and environmental effect along an altitudinal gradient in central Qilian Mountains in western China.

The Qilian Mountains (QLMs) form an important ecological security barrier in western China and a priority area for biodiversity conservation. Potentilla parvifolia is a widespread species in the mid-high altitudes of the QLMs and has continuously migrated to higher altitudes in recent years. Understanding the effects of P. parvifolia on microbial community characteristics is important for exploring future changes in soil biogeochemical processes in the QLMs. This study found that P. parvifolia has profound effects on the community structure and ecological functions of soil microorganisms. The stability and complexity of the root zone microbial co-occurrence network were significantly higher than those of bare soils. There was a distinct altitudinal gradient in the effect of P. parvifolia on soil microbial community characteristics. At an elevation of 3204 m, P. parvifolia promoted the accumulation of carbon, nitrogen, and phosphorus and increased sucrase activity and soil C/N while significantly improving the community richness index of fungi (p < .05) compared with that of bacteria and the relative abundance of Ascomycota. The alpha diversity of fungi in the root zone soil of P. parvifolia was also significantly increased at 3550 m altitude. Furthermore, the community similarity distance matrix of fungi showed an evident separation at 3204 m. However, at an altitude of 3750 m, P. parvifolia mainly affected the bacterial community. Potentilla parvifolia increased the bacterial community richness. This is in agreement with the findings based on the functional prediction that P. parvifolia favors the growth and enrichment of denitrifying communities at 3550 and 3750 m. The results provide a scientific basis for predicting the evolutionary trends of the effects of P. parvifolia on soil microbial communities and functions and have important implications for ecological governance in the QLMs.

Emerging Process Modeling Capabilities for Dry Powder Operations for Inhaled Formulations.

Dry powder inhaler (DPI) products are commonly formulated as a mixture of micronized drug particles and large carrier particles, with or without additional fine particle excipients, followed by final powder filling into dose containment systems such as capsules, blisters, or reservoirs. DPI product manufacturing consists of a series of unit operations, including particle size reduction, blending, and filling. This review provides an overview of the relevant critical process parameters used for jet milling, high-shear blending, and dosator/drum capsule filling operations across commonly utilized instruments. Further, this review describes the recent achievements regarding the application of empirical and mechanistic models, especially discrete element method (DEM) simulation, in DPI process development. Although to date only limited modeling/simulation work has been accomplished, in the authors' perspective, process design and development are destined to be more modeling/simulation driven with the emphasis on evaluating the impact of material attributes/process parameters on process performance. The advancement of computational power is expected to enable modeling/simulation approaches to tackle more complex problems with better accuracy when dealing with real-world DPI process operations.

Layer-by-layer microneedle patch with antibacterial and antioxidant dual activities for accelerating bacterial-infected wound healing.

Bacterial-infected wound healing has always been a huge challenge to humans. Owing to the appearance of antibiotic resistance, there is an emergency need to design antibiotic-free wound dressings to treat such wounds. Herein, a novel antibiotic-free microneedle patch was designed, which its backing layer with antioxidant effect was coated with sodium carboxymethyl cellulose, 2-O-α-D-glucopyranosyl-L-ascorbic acid (GLAA), and 2-hydroxypropyltrimethyl ammonium chloride chitosan through electrostatic interaction based on layer-by-layer self-assembly technique, and its tips consisted of gelatin and tannic acid (TA) via hydrogen bonding interaction (CGH/GTA MN patch). The obtained CGH/GTA MN patch could effectively puncture the skin, and exhibit properties of pH-responsive TA and GLAA release. In vitro experiments showed that the obtained CGH/GTA MN patch has excellent antioxidative (scavenging DPPH efficacy is above 80 %, and scavenging ABTS efficiency reaches about 100 %), antibacterial (antibacterial rates of nearly 100 % for both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli)), biodegradable, and biocompatible properties. In the S. aureus-infected rat wounds, the CGH/GTA MN patch could efficiently accelerate infected-wound healing by eliminating S. aureus infection, inhibiting inflammation, promoting angiogenesis, and accelerating epidermal regeneration. Thus, this study will provide a promising strategy to heal bacterial-infected wounds.

SPA-UNet: A liver tumor segmentation network based on fused multi-scale features.

Liver tumor segmentation is a critical part in the diagnosis and treatment of liver cancer. While U-shaped convolutional neural networks (UNets) have made significant strides in medical image segmentation, challenges remain in accurately segmenting tumor boundaries and detecting small tumors, resulting in low segmentation accuracy. To improve the segmentation accuracy of liver tumors, this work proposes space pyramid attention (SPA)-UNet, a novel image segmentation network with an encoder-decoder architecture. SPA-UNet consists of four modules: (1) Spatial pyramid convolution block (SPCB), extracting multi-scale features by fusing three sets of dilated convolutions with different rates. (2) Spatial pyramid pooling block (SPPB), performing downsampling to reduce image size. (3) Upsample module, integrating dense positional and semantic information. (4) Residual attention block (RA-Block), enabling precise tumor localization. The encoder incorporates 5 SPCBs and 4 SPPBs to capture contextual information. The decoder consists of the Upsample module and RA-Block, and finally a segmentation head outputs segmented images of liver and liver tumor. Experiments using the liver tumor segmentation dataset demonstrate that SPA-UNet surpasses the traditional UNet model, achieving a 1.0 and 2.0% improvement in intersection over union indicators for liver and tumors, respectively, along with increased recall rates by 1.2 and 1.8%. These advancements provide a dependable foundation for liver cancer diagnosis and treatment.

Total Lymph Node Yield Is Associated with Prolonged Survival after Neoadjuvant Chemotherapy in ypN0 Gastric Cancer Patients.

INTRODUCTION: Lymph node status after neoadjuvant chemotherapy (NAC) plays the main role in predicting the survival of gastric cancer (GC) patients who underwent curative gastrectomy after NAC. NAC can reduce the number of involved lymph nodes. However, it is unknown whether other variables are associated with the survival outcomes for ypN0 GC patients. It is unknown whether lymph node yield (LNY) has prognostic value in ypN0 GC patients treated with NAC plus surgery. METHODS: In this retrospective study, we reviewed the data of patients treated with NAC plus gastrectomy and identified those with ypN0 disease. The LNY cut-off was calculated using the X-tile program to determine the greatest actuarial survival difference. Patients were categorized into the downstaged N0 (cN+/ypN0) and natural N0 (cN0/ypN0) groups based on nodal status. Multivariate analysis was used to identify the prognostic factors and the association between LNY and prognosis. RESULTS: A total of 211 GC patients with ypN0 status were included. The optimal LNY cut-off was 23. Kaplan-Meier analysis revealed no significant difference in overall survival between the natural and downstaged N0 groups, while ypN0 GC patients with an LNY of ≥24 had significantly longer overall survival than those with an LNY of ≤23. Univariate analysis identified that LNY, cT stage, tumor location, ypT stage, perineural invasion, lymphovascular invasion, tumor size, Mandard tumor regression grade, and extent of gastrectomy were significantly associated with overall survival. Multivariate analysis confirmed that perineural invasion (hazard ratio, 4.246; p < 0.001), lymphovascular invasion (hazard ratio, 2.694; p = 0.048), and an LNY of ≥24 (hazard ratio, 0.394; p = 0.011) were independent prognostic factors. CONCLUSIONS: Patients with natural and downstaged ypN0 GC had similar overall survival after NAC. LNY was an independent prognostic factor in these patients, and an LNY of ≥24 predicted prolonged overall survival.

Layer-by-Layer Microneedle-Mediated rhEGF Transdermal Delivery for Enhanced Wound Epidermal Regeneration and Angiogenesis.

Appropriate treatments for acute traumas tend to avoid hemorrhages, vascular damage, and infections. However, in the homeostasis-imbalanced wound microenvironment, currently developed therapies could not precisely and controllably deliver biomacromolecular drugs, which are confronted with challenges due to large molecular weight, poor biomembrane permeability, low dosage, rapid degradation, and bioactivity loss. To conquer this, we construct a simple and effective layer-by-layer (LBL) self-assembly transdermal delivery patch, bearing microneedles (MN) coated with recombinant human epidermal growth factor (LBL MN-rhEGF) for a sustained release to wound bed driven by typical electrostatic force. Pyramidal LBL MN-rhEGF patches hold so enough mechanical strength to penetrate the stratum corneum, and generated microchannels allow rhEGF direct delivery in situ. The administrable delivery of biomacromolecular rhEGF through hierarchically coated MN arrays follows the diffusion mechanism of Fick's second law. Numerous efforts further have illustrated that finger-pressing LBL MN-rhEGF patches could not only promote cell proliferation of normal human dermal fibroblasts (NHDF) and human umbilical vein endothelial cells (HUVEC) in vitro but also take significant effects (regenerative epidermis: ∼144 µm; pro-angiogenesis: higher CD31 expression) in accelerating wound healing of mechanically injured rats, compared to the traditional dressing, which relies on passive diffusion. Our proof-of-concept features novel LBL biomacromolecular drug-delivery systems and self-administrated precision medicine modes at the point of care.

Lobaplatin-based prophylactic hyperthermic intraperitoneal chemotherapy for T4 gastric cancer patients: A retrospective clinical study.

Objective: To explore the clinical efficacy of lobaplatin-based prophylactic hyperthermic intraperitoneal chemotherapy (HIPEC) for patients with T4 gastric cancer after surgery and to evaluate its impact on survival. Materials and methods: Data on patients with T4 gastric cancer who underwent radical gastric resection between March 2016 and August 2017 were collected from the National Cancer Center and Huangxing Cancer Hospital. Enrolled patients were divided into two groups according to receiving or not receiving HIPEC. Results: A total of 106 patients were included in this study; among them, 51 patients underwent radical gastric resection plus prophylactic HIPEC, and 55 patients underwent radical gastric resection only. The baseline characteristics were well balanced between the two groups. The postoperative platelet counts in the HIPEC group were significantly lower than those in the non-HIPEC group (P < 0.05); however, we did not observe any occurrences of serious bleeding in the HIPEC group. There were no significant differences in the postoperative complication rates between the two groups (P > 0.05). The postoperative (1 month) CEA, CA19-9, and CA72-4 levels in the HIPEC group were significantly decreased in the HIPEC group (P < 0.05). At a median follow-up of 59.3 months, 3 (5.5%) patients in the HIPEC group experienced peritoneal recurrence, and 10 (18.2%) patients in the non-HIPEC group experienced peritoneal recurrence (P < 0.05). Both groups had comparable 5-year overall survival (OS) rates (41.1% HIPEC group vs. 34.5% non-HIPEC group, P = 0.118). The 5-year disease-free survival was significantly higher in the HIPEC group than in the non-HIPEC group (28.6% versus 39.7%, p = 0.046). Conclusions: Lobaplatin-based prophylactic HIPEC is feasible and safe for patients with T4 gastric cancer and does not increase postoperative adverse effects. The use of HIPEC showed a significant decrease in the incidence of local recurrence rates and blood tumor marker levels. The 5-year disease-free survival was significantly higher in the HIPEC group; however, the 5-year OS benefit was not found in T4 stage patients.

Data-driven multi-joint waveguide bending sensor based on time series neural network.

Due to the bulky interrogation devices, traditional fiber optic sensing system is mainly connected by wire or equipped only for large facilities. However, the advancement in neural network algorithms and flexible materials has broadened its application scenarios to bionics. In this paper, a multi-joint waveguide bending sensor based on color dyed filters is designed to detect bending angles, directions and positions. The sensors are fabricated by casting method using soft silicone rubber. Besides, required optical properties of sensor materials are characterized to better understand principles of the sensor design. Time series neural networks are utilized to predict bending position and angle quantitatively. The results confirm that the waveguide sensor demodulated by the data-driven neural network algorithm performs well and can be used for engineering applications.

What happens to gut microorganisms and potential repair mechanisms when meet heavy metal(loid)s.

Heavy metal (loid) pollution is a significant threat to human health, as the intake of heavy metal (loid)s can cause disturbances in intestinal microbial ecology and metabolic disorders, leading to intestinal and systemic diseases. Therefore, it is important to understand the effects of heavy metal (loid)s on intestinal microorganisms and the necessary approaches to restore them after damage. This review provides a summary of the effects of common toxic elements, such as lead (Pb), cadmium (Cd), chromium (Cr), and metalloid arsenic (As), on the microbial community and structure, metabolic pathways and metabolites, and intestinal morphology and structure. The effects of heavy metal (loid)s on metabolism are focused on energy, nitrogen, and short-chain fatty acid metabolism. We also discussed the main solutions for recovery of intestinal microorganisms from the effects of heavy metal (loid)s, namely the supplementation of probiotics, recombinant bacteria with metal resistance, and the non-toxic transformation of heavy metal (loid) ions by their own intestinal flora. This article provides insight into the toxic effects of heavy metals and As on gut microorganisms and hosts and provides additional therapeutic options to mitigate the damage caused by these toxic elements.

LBL Noninvasively Peelable Biointerfacial Adhesives for Cutaneo-Inspired pH/Tactility Artificial Receptors.

Besides barrier functions, skin possesses multiple sentiences to external stimuli (e.g., temperature, force, and humidity) for human-outside interaction. Thus, skincare should be taken very seriously, especially by patients with sensory disorders. However, currently available skin-mimicking devices are always limited by so much insufficient response functions and nontunable interface behaviors so as not to realize precise health monitoring and self-defense against injury. Herein, a bioinspired cutaneous receptor-perceptual system (CRPS) patch is presented, integrating hybrid pH indicators and triboelectric nanogenerators into biointerface film-adhesives that are fabricated through facile layer-by-layer (LBL) self-assembly of amide and Schiff-base linkages between alginate grafted with N-hydroxysuccinimide ester (AN), tannic acid (TA), and polyethylenimine (PEI). This CRPS patch is adhered robustly to the soft-curved skin surface without failure via "molecular suturing," and amino acid enables its benign peel-on-demand from tissue interfaces. Postdamage self-healing brings it without surgical reoperation, avoiding extra cost, pain, as well as infection risks. Significantly, CRPS patches as artificial chemo/mechanoreceptors can remotely visualize skin physiological status by pH-induced chromism using smartphones and prevent skin contact injury by tactility-driven self-powered electrical signals. Overall, the LBL-based strategy to create controllably biointerface-adhesive CRPS patches will usher in a new era of the mobihealth care platform supporting smart diagnosis and self-protection.