Nanotechnology-enabled topical delivery of therapeutics in chronic rhinosinusitis.

Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the paranasal sinuses which represents a significant health burden due to its widespread prevalence and impact on patients' quality of life. As the molecular pathways driving and sustaining inflammation in CRS become better elucidated, the diversity of treatment options is likely to widen significantly. Nanotechnology offers several tools to enhance the effectiveness of topical therapies, which has been limited by factors such as poor drug retention, mucosal permeation and adhesion, removal by epithelial efflux pumps and the inability to effectively penetrate biofilms. In this review, we highlight the successful application of nanomedicine in the field of CRS therapeutics, discuss current limitations and propose opportunities for future work.

Chronic sinusitis is a common inflammatory condition of the sinuses, which affects patients' quality of life and consumes significant healthcare resources. It is primarily treated with corticosteroids, a type of medication that reduces inflammation, as a nasal spray or taken orally. Nasal sprays are preferred, to minimize side effects elsewhere in the body. Recently, another class of drugs ­ 'biologic agents' ­ has been approved for a subtype of chronic sinusitis that causes polyps (grape-like swellings of the sinus lining). However, a lasting cure is elusive, because inflammation frequently returns once these medications are stopped. As our understanding of what causes chronic sinusitis improves, researchers are seeking therapies that more accurately target the cause of inflammation, rather than broadly suppressing all types of inflammation using corticosteroids. The use of nanotechnology allows the design of drugs to overcome various challenges in treating chronic sinusitis, potentially enabling more accurate delivery of drugs into the sinuses, improving drugs' ability to remain on the sinus lining and penetrate it, reducing the amount of drug lost due to the action of outflow pumps and overcoming additional defenses built up by bacteria when they form thick films. Here, we describe how nanomedicine has been used to develop drugs for chronic sinusitis, discuss current limitations and propose opportunities for future work.

Association Between 18F-Fluorodeoxyglucose Uptake and Mutation Status of Epidermal Growth Factor Receptor in Sinonasal Tract Cancer.

BACKGROUND/AIM: The Warburg effect of cancer has been applied to detect various carcinomas though the 18F-fluorodeoxyglucose (18F-FDG) uptake on positron emission tomography with computed tomography (PET/CT). 18F-FDG-PET/CT in lung cancer predicted the mutation status of epidermoid growth factor receptor (EGFR). This study aimed to investigate whether 18F-FDG uptake parameters were significantly related to EGFR mutation status in patients with sinonasal tract squamous cell carcinoma (STSCC). PATIENTS AND METHODS: Twenty-nine tumor specimens of primary STSCC from patients with definitive treatment were collected. RESULTS: The 18F-FDG uptake from primary tumors was not different between mutant- and wild-status of EGFR on either Mann-Whitney U-test or the receiver operating curve. A metabolic tumor volume of ≥25 with the minimum p-value from the log-rank test for STSCC-specific survival was associated with a significantly shorter STSCC-specific, disease-free, local recurrence-free survival on the univariate and multivariate analyses adjusted for the clinical stage, treatment, and EGFR status. CONCLUSION: 18F-FDG-PET/CT did not predict mutation of the EGFR status in STSCC.

Optimal Combination of Neuroendocrine Markers for the Detection of High-Grade Neuroendocrine Tumors of the Sinonasal Tract and Lung.

PURPOSE OF REVIEW: Identification of neuroendocrine (NE) differentiation is critical to the classification of head and neck (HN) and lung tumors. In combination with tumor morphology, immunohistochemical (IHC) documentation of NE differentiation is necessary for the diagnosis of NE tumors. The purpose of this study is to determine the sensitivity and concordance of two novel NE markers (mASH1, INSM1) across a group of high-grade NE tumors of the sinonasal tract and lung, and to compare their expression with the current widespread use of conventional NE markers, synaptophysin (SYN) and chromogranin A (CGA). In addition, expression of PARP1 is examined as a potential novel therapeutic target. RECENT FINDINGS: Thirty-nine high-grade NE tumors, 23 of the HN and 16 of the lung, were reevaluated by two subspecialized HN and thoracic pathologists, and subsequently stained with mASH1, INSM1, and PARP1. Sensitivity and degree of concordance of all possible combinations of markers were assessed. Sensitivities (standard error) were as follows: mASH1 41% (0.08), INSM1 44% (0.08), SYN 56% (0.08), and CGA 42% (0.09); combination of all four NE markers: 73% (0.08). Sensitivity and standard error for PARP1 was 90% and 0.05, respectively. Highest sensitivity to detect NE differentiation in high-grade NE tumors of the HN and thoracic region was achieved with a combination of four NE markers. Moderate concordance was found with combinations of mASH1 and INSM1 and traditional NE markers, respectively. Consistent overexpression of PARP1 in high-grade tumors with NE differentiation in the HN and lung opens eligibility for PARP1 inhibitor trials.

[IgG4-related disease in nasal cavity and paranasal sinuses: a clinicopathological analysis of ten cases].

Objective: To study clinicopathological features and differential diagnosis of IgG4-related diseases (IgG4-RD) in nasal cavity and paranasal sinuses. Methods: A retrospective analysis was performed in patients presenting initially with rhinosinusitis or a nasal mass, who also underwent nasal mucosa biopsy in Beijing Tongren Hospital Affiliated to Capital Medical University, from March 2016 to March 2021. According to the latest international classification diagnostic criteria of IgG4-RD published by the American Society of Rheumatology (ACR)/European Association for Rheumatology (EULAR) in 2019, 10 cases of nasal cavity and paranasal sinuses IgG4-RD were diagnosed and included in the study. The clinical features, histopathology and immunohistochemical expression of IgG and IgG4 were analyzed. Results: Among the 10 patients, five patients were male and five female. The age ranged from 30 to 71 years (median 52.7 years). Nasal polyp/nasal masses were seen in six cases, and lacrimal gland swelling was found in four cases. The serum IgG and IgG4 level was increased in four cases. Microscopically, all 10 cases showed intense lymphoplasmocytic infiltration and varying degrees of fibrosis in nasal or sinus mucosa, while four cases showed occlusive vasculitis. The number of IgG4 positive plasma cells in nasal mucosa was more than 10/high power field (HPF), with a mean of 67/HPF. The number of IgG4 positive plasma cells in the cases with severe fibrosis was significantly lower than in those without. The ratio of IgG4+/IgG+plasma cells was higher than 40% in six cases. Conclusions: IgG4-RD in nasal cavity and paranasal sinuses is a local manifestation of a systemic disease, while nasal cavity and paranasal sinuses are rarely involved by IgG4-RD. The diagnosis is based on clinical symptoms, imaging, IgG4-related serology and histopathologic scores. Histopathology has a core diagnostic value. IgG4 serology and imaging have important diagnostic values in the cases without biopsy.

Comparison of Sinus Deposition from an Aqueous Nasal Spray and Pressurised MDI in a Post-Endoscopic Sinus Surgery Nasal Replica.

BACKGROUND: Optimising intranasal distribution and retention of topical therapy is essential for effectively managing patients with chronic rhinosinusitis, including those that have had functional endoscopic sinus surgery (FESS). This study presents a new technique for quantifying in vitro experiments of fluticasone propionate deposition within the sinuses of a 3D-printed model from a post-FESS patient. METHODS: Circular filter papers were placed on the sinus surfaces of the model. Deposition of fluticasone on the filter paper was quantified using high-performance liquid chromatography (HPLC) assay-based techniques. The deposition patterns of two nasal drug delivery devices, an aqueous nasal spray (Flixonase) and metered dose inhaler (Flixotide), were compared. The effects of airflow (0 L/min vs. 12 L/min) and administration angle (30° vs. and 45°) were evaluated. RESULTS: Inhaled airflow made little difference to sinus deposition for either device. A 45° administration angle improved frontal sinus deposition with the nasal spray and both ethmoidal and sphenoidal deposition with the inhaler. The inhaler provided significantly better deposition within the ethmoid sinuses (8.5x) and within the maxillary sinuses (3.9x) compared with the nasal spray under the same conditions. CONCLUSION: In the post-FESS model analysed, the inhaler produced better sinus deposition overall compared with the nasal spray. The techniques described can be used and adapted for in vitro performance testing of different drug formulations and intranasal devices under different experimental conditions. They can also help validate computational fluid dynamics modelling and in vivo studies.

An adjuvant strategy enabled by modulation of the physical properties of microbial ligands expands antigen immunogenicity.

Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.

Formulation, optimization, and nephrotoxicity evaluation of an antifungal in situ nasal gel loaded with voriconazole‒clove oil transferosomal nanoparticles.

Fungal infections of the paranasal cavity are among the most widely spread illnesses nowadays. The aim of the current study was to estimate the effectiveness of an in situ gel loaded with voriconazole‒clove oil nano-transferosomes (VRC-CO-NT) in enhancing the activity of voriconazole against Aspergillus flavus, which causes rhinosinusitis. The nephrotoxic side effects of voriconazole may be reduced through the incorporation of the clove oil, which has antioxidant activity that protects tissue. The Box‒Behnken design was applied to formulate the VRC-CO-NT. The particle size, entrapment efficiency, antifungal inhibition zone, and serum creatinine concentration were considered dependent variables, and the soybean lecithin, VRC, and CO concentrations were considered independent ones. The final optimized formulation was loaded into a deacetylated gellan gum base and evaluated for its gelation, rheological properties, drug release profile, permeation capabilities, and in vivo nephrotoxicity. The optimum formulation was determined to be composed of 50 mg/mL lecithin, 18 mg/mL VRC, and 75 mg/mL CO, with a minimum particle size of 102.96 nm, an entrapment efficiency of 71.70%, an inhibition zone of 21.76 mm, and a serum creatinine level of 0.119 mmol/L. The optimized loaded in situ gel released 82.5% VRC after 12 hours and resulted in a 5.4-fold increase in drug permeation. The in vivo results obtained using rabbits resulted in a nonsignificant differentiation among the renal function parameters compared with the negative control group. In conclusion, nasal in situ gel loaded with VRC-CO-NT is considered an efficient novel carrier with enhanced antifungal properties with no signs of nephrotoxicity.

Effects of endoscopic sinus surgery on nasal spray deposition using dye-based methods for humans and a human silicone sinonasal cavity model.

OBJECTIVE: We have evaluated that the deposition patterns of corticosteroid nasal spray in the sinonasal cavity of both post-operated human cases, which were further compared with a computed tomography-based sinonasal airway model. METHODS: Fifty-one patients with chronic rhinosinusitis following an endoscopic sinus surgery were enrolled in this study. Nasal spray mometasone furoate hydrate (Nasonex®) containing 0.1% indigocarmine was applied to the patients' nasal cavities and the sinonasal cavity was observed by endoscopy and video documentation. A single plaster sinonasal model was used to quantify the sinonasal deposition of nasal sprays containing 10% red ink solution using 12 round paper strips. RESULTS: The predominant areas of the spray deposition of the operated sinonasal cavities were recognized in the ethmoid sinus and the olfactory cleft in the human study. The droplets were mainly deposited in the inferior turbinate followed by the posterior part of the ethmoid sinus, the olfactory cleft, and anterior part of the ethmoid sinus in a sinonasal model. CONCLUSION: The corticosteroid nasal spray efficiently reached the olfactory cleft and the ethmoid sinus in post-operative conditions, which was demonstrated by post-operated human cases and a computed tomography-based sinonasal airway model.

A novel nasal co-loaded loratadine and sulpiride nanoemulsion with improved downregulation of TNF-α, TGF-ß and IL-1 in rabbit models of ovalbumin-induced allergic rhinitis.

PURPOSE: The work aimed to develop a co-loaded loratadine and sulpiride nasal nanoemulsion for allergic rhinitis management. METHODS: Compatibility studies were conducted adopting differential scanning calorimetry and Fourier transform infrared spectroscopy. Nanoemulsion formulations were prepared using soybean lecithin, olive oil and tween 80. Sodium cholate and glycerol were employed as co-surfactants. Nanoemulsions were assessed for viscosity, pH, droplet size, polydispersity index, zeta potential, electrical conductivity, entrapment, In vitro drug release and corresponding kinetics. Stability of the selected formulation was investigated. The biological effectiveness was evaluated in rabbit models of ovalbumin-induced allergic rhinitis by measuring TNF-α, TGF-ß and IL-1. RESULTS: Compatibility studies revealed absence of drug/drug interactions. Nanoemulsions exhibited > 90% entrapment efficiency. The selected nanoemulsion demonstrated small droplet size (85.2 ± 0.2 nm), low PDI (0.35 ± 0.0) and appropriate Zeta Potential (-23.3 ± 0.2) and stability. It also displayed enhanced in vitro drug release following the Higuashi Diffusion and Baker-Lonsdale models. The mean relative mRNA expression of TNF-α, IL-1 and TGF-ß significantly decreased from 9.59 ± 1.06, 4.15 ± 0.02 and 4.15 ± 0.02 to 1.28 ± 0.02, 1.93 ± 0.06 and 1.56 ± 0.02 respectively after treatment with the selected nanoemulsion formulation. CONCLUSION: The results reflected a promising potent effect of the combined loratadine and sulpiride nasal nanoemulsion in managing the symptoms of allergic rhinitis.

The impact of ivacaftor on sinonasal pathology in S1251N-mediated cystic fibrosis patients.

IMPORTANCE: Sinonasal symptoms in patients suffering from cystic fibrosis can negatively influence the quality of life and sinuses can be a niche for pathogens causing infection and inflammation leading to a decrease of lung function. Ivacaftor, a potentiator of the Cystic Fibrosis Transmembrane Conductance Regulator protein, has shown improvement in pulmonary function in cystic fibrosis patients with different forms of class III gating mutations. However, the effects of ivacaftor on sinonasal pathology have hardly been studied. OBJECTIVE: To determine the impact of ivacaftor therapy on sinonasal pathology in patients with cystic fibrosis with an S1251N mutation. DESIGN: Prospective observational mono-center cohort study, between June 2015 and December 2016. SETTING: A tertiary referral center in Utrecht, The Netherlands. PARTICIPANTS: Eight patients with cystic fibrosis with an S1251N mutation, treated with the potentiator ivacaftor were investigated. EXPOSURES: Ivacaftor (Kalydeco, VX-770) therapy. Computed tomography imaging of paranasal sinuses. Nasal nitric oxide concentration measurements and nasal endoscopy. MAIN OUTCOMES AND MEASURES: Primary outcome is opacification of paranasal sinuses examined with computed tomography scan analysis and scaled by the modified Lund-Mackay score before and one year after treatment. Secondary outcomes are nasal nitric oxide concentration levels, sinonasal symptoms and nasal endoscopic findings before and approximately two months and in some cases one year after treatment. RESULTS: Computed tomography scan analysis showed a significant decrease in opacification of the majority of paranasal sinuses comparing the opacification score per paranasal sinus before and after one year of treatment with ivacaftor. Median nasal nitric oxide levels significantly improved from 220.00 (IQR:136.00-341.18) to 462.84 (IQR:233.17-636.25) (p = 0.017) parts per billion. Likewise, the majority of sinonasal symptoms and nasal endoscopic pathology decreased or resolved at two months after the use of ivacaftor. CONCLUSION AND RELEVANCE: Ivacaftor appears to improve sinonasal outcome parameters and thereby sinonasal health in patients with cystic fibrosis with an S1251N mutation.

Cell division rates decrease with age, providing a potential explanation for the age-dependent deceleration in cancer incidence.

A new evaluation of previously published data suggested to us that the accumulation of mutations might slow, rather than increase, as individuals age. To explain this unexpected finding, we hypothesized that normal stem cell division rates might decrease as we age. To test this hypothesis, we evaluated cell division rates in the epithelium of human colonic, duodenal, esophageal, and posterior ethmoid sinonasal tissues. In all 4 tissues, there was a significant decrease in cell division rates with age. In contrast, cell division rates did not decrease in the colon of aged mice, and only small decreases were observed in their small intestine or esophagus. These results have important implications for understanding the relationship between normal stem cells, aging, and cancer. Moreover, they provide a plausible explanation for the enigmatic age-dependent deceleration in cancer incidence in very old humans but not in mice.

Melatonin deficiency at tissue level: a possible aetiological factor in nasal polyposis.

OBJECTIVE: The aim of this study was to examine whether melatonin is involved in the pathogenesis of nasal polyposis. METHOD: This study included 29 patients with nasal polyposis and undergoing functional endoscopic sinus surgery. As a control group, 26 patients who had been operated on for a deviated nasal septum and concha bullosa were enrolled. Samples were taken from the nasal polyp tissue and from the resected middle concha bullosa mucosa of the control group. Serum samples were taken from all patients. RESULTS: It was found that the tissue and serum melatonin levels in the nasal polyp group were significantly lower compared with the tissue and serum melatonin levels in the control group. CONCLUSION: In nasal polyposis, the melatonin level in the serum and tissue is lower than in individuals without polyposis. This deficiency may play a role in the pathogenesis of nasal polyposis.

Correlation Between HMGB1 and TLR4 Expression in Sinonasal Mucosa in Patients With Chronic Rhinosinusitis.

OBJECTIVES: Chronic rhinosinusitis (CRS) is one of the most common inflammations in the upper airway. Despite the wide prevalence of CRS, the pathogenesis of this disease is poorly understood. Several components of the innate immune system may play a significant role in CRS, including Toll-like receptor 4 (TLR4), TLR9, and high-mobility group box 1 protein (HMGB1). This study was conducted to determine the expression of TLR4, TLR9, HMGB1, and pNFκ-B p65 in paraffin-embedded blocks of patients with CRS with nasal polyps compared with those of the control group. METHODS: Twenty-six formalin-fixed, paraffin-embedded samples from patients with confirmed CRS and 26 patients undergoing septoplasty due to anatomic variations and no other inflammatory nasal diseases as the control group were assessed. Expression patterns of HMGB1, TLR9, TLR4, and pNFκ-B p65 genes were examined using real-time quantitative reverse transcription polymerase chain reaction (Real-Time qRT-PCR). Statistical analyses were performed with SPSS and analyzed using unpaired 2-tailed t tests or 1-way analysis of variance. RESULTS: Real-time PCR showed that the expression level of HMGB1 messenger RNA was significantly increased in the tissues of patients with CRS compared with controls (P < .05). The other 3 genes were also upregulated in the patients, but were not significant compared with control. Analysis of the Pearson correlation coefficient (r) revealed a significant positive correlation between HMGB1 and TLR4 (r = 0.79, P < .05) in patients and negative correlation between TLR4 and NfκB in the control group (r = 0.94; P < .05). CONCLUSIONS: Both HMGB1 and TLR4 are increased in the paranasal sinus mucosa of patients with CRS. These results suggest a possible contribution of HMGB1 and its internal receptor (TLR4) in the pathophysiology of CRS.

Rat sinus mucosa- and periosteum-derived exosomes accelerate osteogenesis.

Guided bone regeneration (GBR) is commonly used for alveolar bone augmentation. The paracrine mechanism in the field of bone tissue engineering has been emphasized in recent years and exosomes are considered to have the potential of promoting osteogenesis. We aimed to study the influence of sinus mucosa and periosteum on bone regeneration through paracrine stimulation, especially via exosomes, and compare the differences between them. Here, we report that conditioned medium (CM) from sinus mucosa-derived cells (SMCs) and periosteum-derived cells (PCs) and the isolated exosomes enhanced the proliferation, migration and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs) in vitro. A rat model of femoral bone defects was used to demonstrate that the exosomes derived from SMCs (SMC-Exos) and PCs (PC-Exos) can accelerate bone formation in vivo. Furthermore, we present a preliminary discussion of the possible functional components involved in the effects of SMC-Exos and PC-Exos on bone regeneration. In conclusion, these results demonstrated that the sinus mucosa and periosteum can accelerate osteogenesis through paracrine effects and the exosomes play important roles in this process.

[Histamine receptors in chronic inflammatory diseases of the nose and paranasal sinuses]. / Histaminrezeptoren bei chronisch-entzündlichen Erkrankungen der Nase und Nasennebenhöhlen.

BACKGROUND: Release of histamine from mast cells and basophils in inflammatory diseases of the nose and paranasal sinuses has been demonstrated in allergic and non-allergic processes. METHODS: A selective literature search was conducted in PubMed and Medline, and publications in German-language journals were additionally analyzed. RESULTS: The histamine receptors H1-H4 play a role in otorhinolaryngologic inflammatory diseases. To date, the histamine receptor subtype 4 (H4R), which is functionally expressed by immune cells in chronic inflammatory diseases, has received little attention. Stimulation of H4R influences the release of cytokines and chemokines as well as the migration behavior of immune cells. In animal models blockade of H4R reduced inflammation symptoms and pruritus. CONCLUSIONS: H4R plays a key role in the pathogenesis of chronic inflammatory diseases and may represent an interesting future therapeutic target.

Combined Modality Management of Sinonasal Anaplastic Lymphoma Kinase-Positive Anaplastic Large Cell Lymphoma in a Young Adult-Report of a Rare Case.

Sinonasal anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL) without nodal involvement is extremely rare and the rarity of this tumor often leads to diagnostic dilemma. It has been predominantly reported in pediatric, adolescent and young adult patients, mostly of Asian origin. A 21-year-old female patient presented with history of epistaxis for 1 year. On clinical and radiological examination, there was a 5 cm mass in the right nasal cavity, ethmoid, and frontal sinus. Biopsy at a local center had shown moderately differentiated squamous cell carcinoma. Rebiopsy at our center showed possibility of a hematolymphoid malignancy(pancytokeratin-, CD45+, CD3-, CD20-) and further immunohistochemistry studies(CD4+, CD43+, CD30+, ALK+) revealed ALK-positive ALCL. Rest of the lymphoma work-up was essentially normal and she had stage IE disease. She was treated with a combination of four cycles of cyclophosphamide, hydroxydaunorubicin, vincristine, and prednisolone (CHOP) regimen followed by local radiotherapy (36 Gray/20 fractions/4 weeks) by three-dimensional conformal technique. She tolerated the treatment well without any severe toxicity and had complete clinical and radiological response. At last follow-up visit, 40 months from the initial diagnosis, she was alive and disease free. Sinonasal ALK-positive ALCL is a rare tumor, which can be effectively treated with a combination of multiagent CHOP/CHOP-like regimen and local conformal radiotherapy.

Comparative study of simulated nebulized and spray particle deposition in chronic rhinosinusitis patients.

BACKGROUND: Topical intranasal drugs are widely prescribed for chronic rhinosinusitis (CRS), although delivery can vary with device type and droplet size. The study objective was to compare nebulized and sprayed droplet deposition in the paranasal sinuses and ostiomeatal complex (OMC) across multiple droplet sizes in CRS patients using computational fluid dynamics (CFD). METHODS: Three-dimensional models of sinonasal cavities were constructed from computed tomography (CT) scans of 3 subjects with CRS refractory to medical therapy using imaging software. Assuming steady-state inspiratory airflow at resting rate, CFD was used to simulate 1-µm to 120-µm sprayed droplet deposition in the left and right sinuses and OMC with spray nozzle positioning as in current nasal spray use instructions. Zero-velocity nebulization simulations were performed for 1-µm to 30-µm droplet sizes, maximal sinus and OMC deposition fractions (MSDF) were obtained, and sizes that achieved at least 50% of MSDF were identified. Nebulized MSDF was compared to sprayed droplet deposition. We also validated CFD framework through in vitro experiments. RESULTS: Among nebulized droplet sizes, 11-µm to 14-µm droplets achieved at least 50% of MSDF in all 6 sinonasal cavities. Four of 6 sinonasal cavities had greater sinus and OMC deposition with nebulized droplets than with sprayed droplets at optimal sizes. CONCLUSION: Nebulized droplets may target the sinuses and OMC more effectively than sprayed particles at sizes achieving best deposition. Further studies are needed to confirm our preliminary findings. Several commercial nasal nebulizers have average particle sizes outside the optimal nebulized droplet size range found here, suggesting potential for product enhancement.