To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
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 evaluate the healing and hearing outcomes related to the everted or inverted edge area on slap- and fist-induced large tympanic membrane perforations.
A total of 120 patients with slap- or fist-induced tympanic membrane perforations, with inverted or everted edges, affecting 50–75 per cent of the entire tympanic membrane, were randomly divided into 2 groups: an edge approximation group and a spontaneous healing group. The edge approximation group was divided into subgroups A and B based on the reversed edge area (reversed edge was more or less than 50 per cent of the total perforation, respectively). Healing outcomes and hearing improvements at six months were compared.
The data of 118 patients were analysed. The closure rate of perforations in subgroup A, subgroup B, and the spontaneous healing group was 90.9 per cent, 92.1 per cent and 84.5 per cent, respectively; the difference between the three groups was not significant (p = 0.393).
The area of reversed edges for slap- or fist-induced tympanic membrane perforations did not seem to affect healing and hearing outcomes, regardless of edge approximation and everted or inverted edges.
This study aimed to analyse the common presentations and treatment outcomes in cases involving nasal foreign bodies.
A retrospective study was carried out over three years, from January 2014 to December 2017. Patient biodata, clinical presentation, nasal foreign body type and management outcome data were obtained from the medical records and analysed.
A total of 341 cases were analysed. The average patient age was 3.7 ± 1.2 years (range, 1–19 years).Of the nine cases involving button batteries, septal perforation was initially seen in four cases and three cases had subsequent septal perforation.
Only button battery nasal foreign bodies were associated with increased septal perforation. Use of physiological seawater nasal spray was found to reduce the likelihood of septal perforation. Most nasal foreign bodies could be removed under local anaesthesia.
To review the origins of epistaxis in patients with unknown bleeding sites.
This consecutive case series included 26 patients with unknown bleeding sites previously considered to have posterior epistaxis. All patients had previously been examined endoscopically at least once, and were again examined with 30°, 45° and 70° endoscopes.
The bleeding site was at the: anterior end of the lateral wall of the inferior meatus in one patient (3.8 per cent); anterosuperior lateral wall of the nasal cavity in five patients (19.2 per cent); anterior nasal cavity roof in seven patients (26.9 per cent); anterosuperior part of the cartilaginous septum in nine patients (34.6 per cent); ostium pharyngeum tubae in two patients (7.7 per cent); and anterior nasal base in two patients (7.7 per cent). The morphology of the bleeding point showed: nasal mucosa ulceration in 1 patient, isolated primary telangiectasia in 3 patients, prominent vessels in 5 patients and capillary angioma in 17 patients.
Epistaxis originating from the anterosuperior nasal cavity and nasopharynx can be easily misdiagnosed as posterior epistaxis or unknown bleeding sites. Areas that should be considered as possible origins of epistaxis in cases with unknown bleeding sites were identified.
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.
Background: Human induced pluripotent stem cell-derived neural stem cells (hiPS-NSCs) represent an exciting therapeutic approach for traumatically spinal cord injury (SCI). Unfortunately, most patients are the in chronic injury phase where a dense perilesional chondroitin sulfate proteoglycan (CSPG) scar significantly hinders regeneration. CSPG-degrading enzymes can enhance NSC-mediated recovery, however, nonspecific intrathecal administration causes off-target effects. We aimed to genetically engineer hiPS-NSCs to express a scar-degrading ENZYME into their local environment to enhance functional recovery. Methods: A bicistronic scar-degrading ENZYME and RFP reporter vector was non-virally integrated into hiPS-NSCs and monoclonalized. ENZYME activity was assessed by WST-1 and DMMB biochemical assays and an in vitro CSPG spot assay with hiPS-NSC-derived neurons. To assess in vivo efficacy, T-cell deficient rats (N=60) with chronic (8wk) C6-7 SCIs were randomized to receive (1)SMaRT cells, (2)hiPS-NSCs, (3)vehicle, or (4)sham surgery. Results: SMaRT cells retained key hiPS-NSC characteristics while stably expressing ENZYME. The expressed ENZYME could appropriately degrade in vitro and ex vivo CSPGs. While blinded neurobehavioural and immunohistochemical assessments are ongoing at 40wks post-injury, an interim analysis demonstrated human cells extending remarkably long (≥20,000µm) axons along host white matter tracts. Conclusions: This work provides exciting proof-of-concept data that genetically-engineered SMaRT cells can degrade CSPGs and human NSCs can extend long-distance processes in chronic SCI.
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.