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Each species is subject to various biotic and abiotic factors during growth. This paper formulates a deterministic model with the consideration of various factors regulating population growth such as age-dependent birth and death rates, spatial movements, seasonal variations, intra-specific competition and time-varying maturation simultaneously. The model takes the form of two coupled reaction–diffusion equations with time-dependent delays, which bring novel challenges to the theoretical analysis. Then, the model is analysed when competition among immatures is neglected, in which situation one equation for the adult population density is decoupled. The basic reproduction number
is defined and shown to determine the global attractivity of either the zero equilibrium (when
) or a positive periodic solution (
) by using the dynamical system approach on an appropriate phase space. When the immature intra-specific competition is included and the immature diffusion rate is neglected, the model is neither cooperative nor reducible to a single equation. In this case, the threshold dynamics about the population extinction and uniform persistence are established by using the newly defined basic reproduction number
as a threshold index. Furthermore, numerical simulations are implemented on the population growth of two different species for two different cases to validate the analytic results.
To discuss the reasons for misdiagnosis of supernumerary nasal teeth.
Clinical data of four supernumerary nasal tooth patients were analysed retrospectively at visits to our otolaryngology department between 2005 and 2018.
All four patients were male and had a supernumerary nasal tooth in the right nasal cavity. Three of the four patients had previously been misdiagnosed. All the supernumerary nasal teeth were surrounded by granulation tissue or hypertrophic nasal mucosa, and were subsequently confirmed by computed tomography and endoscopy. The granulation tissue or hypertrophic nasal mucosa was removed using microwave ablation, and the supernumerary nasal teeth successfully removed by endoscopy.
Supernumerary nasal teeth are rare, and are usually misdiagnosed because such teeth are surrounded by hypertrophic nasal mucosa or granulation tissue. They can be confirmed by computed tomography and endoscopy.
To determine the frequency distribution of bleeding sites in idiopathic hidden arterial epistaxis.
In this retrospective cohort study, 107 patients with hidden arterial epistaxis were endoscopically examined for sites of bleeding.
All sites of hidden arterial epistaxis were identified by endoscopic examination. Bleeding sites were identified at initial surgery in 103 patients and during the second surgery in 4. The bleeding sites included: the olfactory cleft region in 47 patients, the inferior meatus region in 29, the middle meatus region in 11, multiple bleeding sites (olfactory cleft and anterior septum) in 3, the anterior roof of the nasal cavity in 4, the nasal floor in 11 and the nasopharynx in 2. The bleeding points showed a white or red volcano-like bump in 75 patients, isolated prominent telangiectasia in 21 and mucosal ulceration in 11.
Common sites of hidden arterial epistaxis include the olfactory cleft, inferior meatus and middle meatus. However, there should be awareness of some uncommon bleeding sites (including the anterior roof of the nasal cavity, the nasal floor and the nasopharynx) and of multiple bleeding sites.
A systematic review was conducted to investigate the effectiveness of fibroblast growth factor-2 on the regeneration of tympanic membrane perforation.
The PubMed database was searched for relevant studies. Experimental studies, human randomised controlled trials, prospective single-arm studies and retrospective studies reporting acute and chronic tympanic membrane perforations in relation to two healing outcomes (success rate and closure time), were selected.
All 11 clinical studies investigating the effect of fibroblast growth factor-2 on traumatic tympanic membrane perforations in humans reported a success rate of 89.3–100 per cent, with a closure time of around 2 weeks. Three studies of fibroblast growth factor-2 combined with Gelfoam showed that the success rate of chronic tympanic membrane perforation was 83–98.1 per cent in the fibroblast growth factor-2 group, but 10 per cent in the gelatine sponge groups.
Fibroblast growth factor-2 with or without biological material patching promotes regeneration in cases of acute and chronic tympanic membrane perforation, and is safe and efficient. However, the best dosage, application time and administration pathway of fibroblast growth factor-2 are still to be elucidated.
To review the history of moist therapy used to regenerate traumatic tympanic membrane perforations.
The literature on topical agents used to treat traumatic tympanic membrane perforations was reviewed, and the advantages and disadvantages of moist therapy were analysed.
A total of 76 studies were included in the analysis. Topical applications of certain agents (e.g. growth factors, Ofloxacin Otic Solution, and insulin solutions) to the moist edges of traumatic tympanic membrane perforations shortened closure times and improved closure rates.
Dry tympanic membrane perforation edges may be associated with crust formation and centrifugal migration, delaying perforation closure. On the contrary, moist edges inhibit necrosis at the perforation margins, stimulate proliferation of granulation tissue and aid eardrum healing. Thus, moist perforation margins upon topical application of solutions of appropriate agents aid the regeneration of traumatic tympanic membrane perforations.
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