Diversification across an altitudinal gradient in the Tiny Greenbul (Phyllastrephus debilis) from the Eastern Arc Mountains of Africa

<p>Abstract</p> <p>Background</p> <p>The Eastern Arc Mountains of Africa have become one of the focal systems with which to explore the patterns and mechanisms of diversification among montane species and populations. One unresolved question is the extent to which populations inhabiting montane forest interact with those of adjacent lowland forest abutting the coast of eastern Africa. The Tiny Greenbul (<it>Phyllastephus debilis</it>) represents the only described bird species within the Eastern Arc/coastal forest mosaic, which is polytypic across an altitudinal gradient: the subspecies <it>albigula </it>(green head) is distributed in the montane Usambara and Nguru Mountains whereas the subspecies <it>rabai </it>(grey head) is found in Tanzanian lowland and foothill forest. Using a combination of morphological and genetic data, we aim to establish if the pattern of morphological differentiation in the Tiny Greenbul (<it>Phyllastrephus debilis</it>) is the result of disruptive selection along an altitudinal gradient or a consequence of secondary contact following population expansion of two differentiated lineages.</p> <p>Results</p> <p>We found significant biometric differences between the lowland (<it>rabai</it>) and montane (<it>albigula</it>) populations in Tanzania. The differences in shape are coupled with discrete differences in the coloration of the underparts. Using multi-locus data gathered from 124 individuals, we show that lowland and montane birds form two distinct genetic lineages. The divergence between the two forms occurred between 2.4 and 3.1 Myrs ago.</p> <p>Our coalescent analyses suggest that limited gene flow, mostly from the subspecies <it>rabai </it>to <it>albigula</it>, is taking place at three mid-altitude localities, where lowland and montane rainforest directly abut. The extent of this introgression appears to be limited and is likely a consequence of the recent expansion of <it>rabai </it>further inland.</p> <p>Conclusion</p> <p>The clear altitudinal segregation in morphology found within the Tiny Greenbul is the result of secondary contact of two highly differentiated lineages rather than disruptive selection in plumage pattern across an altitudinal gradient. Based on our results, we recommend <it>albigula </it>be elevated to species rank.</p

The disruption of proteostasis in neurodegenerative diseases

Cells count on surveillance systems to monitor and protect the cellular proteome which, besides being highly heterogeneous, is constantly being challenged by intrinsic and environmental factors. In this context, the proteostasis network (PN) is essential to achieve a stable and functional proteome. Disruption of the PN is associated with aging and can lead to and/or potentiate the occurrence of many neurodegenerative diseases (ND). This not only emphasizes the importance of the PN in health span and aging but also how its modulation can be a potential target for intervention and treatment of human diseases.info:eu-repo/semantics/publishedVersio

Structural and functional insights into oligopeptide acquisition by the RagAB transporter from Porphyromonas gingivalis

Porphyromonas gingivalis, an asaccharolytic member of the Bacteroidetes, is a keystone pathogen in human periodontitis that may also contribute to the development of other chronic inflammatory diseases. P. gingivalis utilizes protease-generated peptides derived from extracellular proteins for growth, but how these peptides enter the cell is not clear. Here, we identify RagAB as the outer-membrane importer for these peptides. X-ray crystal structures show that the transporter forms a dimeric RagA2B2 complex, with the RagB substrate-binding surface-anchored lipoprotein forming a closed lid on the RagA TonB-dependent transporter. Cryo-electron microscopy structures reveal the opening of the RagB lid and thus provide direct evidence for a ‘pedal bin’ mechanism of nutrient uptake. Together with mutagenesis, peptide-binding studies and RagAB peptidomics, our work identifies RagAB as a dynamic, selective outer-membrane oligopeptide-acquisition machine that is essential for the efficient utilization of proteinaceous nutrients by P. gingivalis

Immigrant influx and generational politics : a comparative case study of Hong Kong and Taiwan

202209 bckwAccepted ManuscriptRGCPublishe

Comprehensive analysis of nodal recurrence of advanced laryngeal carcinoma following surgery

The problems of nodal recurrence after surgical treatment of T3-4 laryngeal carcinoma were analysed. There mere 133 N0 and 66 N+ patients. The 5-year actuarial nodal recurrence rate of N0 patients was 18% and N+ patients was 31%. Nodal recurrence was the commonest site of recurrence. The sites of nodal recurrence of N0 patients were at the level II, III, and IV nodes. Both ipsilateral and contralateral nodal recurrences were common. Of those patients who developed nodal recurrence, 63% patients were feasible for surgical salvage. Surgical salvage, with radical neck dissection was the preferred treatment for nodal recurrence with 38% 5-year survival rate. The 'watchful waiting policy' in the management of N0 neck is an acceptable option with eventual nodal failure rate of 10% after surgical salvage. Close follow-up of patients is mandatory for the early detection of surgically salvageable nodal recurrence.link_to_subscribed_fulltex

Otorrhea after grommet insertion for middle ear effusion in patients with nasopharyngeal carcinoma

Purpose: To document the incidence of complications after myringotomy and grommet insertion in patients with nasopharyngeal carcinoma. The focus is on the incidence of otorrhea and perforation. The possible risk factors for these conditions and treatment response were studied. Materials and Methods: We reviewed the records on 206 ears of 163 patients who suffered from nasopharyngeal carcinoma and underwent myringotomy and grommet insertion in a 7-year period. The follow-up period ranged from 4 weeks to 78 months (median, 9 months). Results: The overall incidence of otorrhea in these ears was 38%. Patients with nasopharyngeal carcinoma (NPC) had a significantly high incidence of postoperative discharge (χ2 test, P ≤ .0001) compared with other patients who underwent myringotomy and grommet insertion. The mean interval between myringotomy and otorrhea was 19.8 weeks. Forty-seven per cent of the ears with a discharge developed otorrhea within 1 month. In 42%, the otorrhea responded to treatment and the ears became dry. After extrusion of the grommet, 29% of those ears with otorrhea ended with an eardrum perforation, and 24% of the ears showed recurrent effusion. Conclusions: For patients with NPC who underwent myringotomy, there was a significant risk of otorrhea (49%) and persistent perforation (29%), and these complications were difficult to manage. We conclude that myringotomy and grommet insertion should not be routinely offered to NPC patients with middle ear effusion.link_to_subscribed_fulltex

Assessment of tracheoesophageal speech in a tonal language: A prospective study

Background: Tracheoesophageal puncture followed by insertion of a voice prosthesis is an increasingly popular method for voice rehabilitation after total laryngectomy. Objectives: To perform a functional assessment of voice produced by means of the Blom-Singer valve in a tonal language (Cantonese). Design: Prospective study. Setting: Hospital referral center. Main Outcome Measure: A 5-point scoring scale was adopted for 15 test items of speech assessment grouped into 4 categories: phonatory skills, articulation, additional factors, and general judgment. The sum of the scores for the 15 items was the final speech score. The final speech score was rated as poor, satisfactory, or excellent if it was in the range of less than 30, 31 to 45, or 46 to 75, respectively. Results: Forty-four users of the Blom-Singer valve who had undergone total laryngectomy and primary tracheoesophageal puncture were available for functional assessment. The final speech score was poor in 2 patients (5%), satisfactory in 4 (9%), and excellent in 38 (86%). Conclusion: Chinese patients can speak satisfactory tonal language with the Blom-Singer voice prosthesis.link_to_subscribed_fulltex

Association between ambient temperatures and mental disorder hospitalizations in a subtropical city: A time-series study of Hong Kong Special Administrative Region

Background Mental disorders have been found to be positively associated with temperature in cool to cold climatic regions but the association in warmer regions is unclear. This study presented the short-term association between temperatures and mental disorder hospitalizations in a subtropical city with a mean annual temperature over 21 °C. Methods Using Poisson-generalized additive models and distributed-lagged nonlinear models, daily mental disorder hospitalizations between 2002 and 2011 in Hong Kong were regressed on daily mean temperature, relative humidity, and air pollutants, adjusted for seasonal trend, long-term trend, day-of-week, and holiday. Analyses were stratified by disease class, gender and age-group. Results 44,600 admissions were included in the analysis. Temperature was positively associated with overall mental-disorder hospitalizations (cumulative relative risk at 28 °C vs. 19.4 °C (interquartile range, lag 0–2 days) = 1.09 (95% confidence interval 1.03, 1.15)), with the strongest effect among the elderly (≥75 years old). Transient mental disorders due to conditions classified elsewhere and episodic mood disorders also showed strong positive associations with temperature. Conclusion This study found a positive temperature–mental-disorder admissions association in a warm subtropical region and the association was most prominent among older people. With the dual effect of global warming and an aging population, targeted strategies should be designed to lower the disease burden.</p

Association between ambient temperatures and mental disorder hospitalizations in a subtropical city: A time-series study of Hong Kong Special Administrative Region

Background Mental disorders have been found to be positively associated with temperature in cool to cold climatic regions but the association in warmer regions is unclear. This study presented the short-term association between temperatures and mental disorder hospitalizations in a subtropical city with a mean annual temperature over 21 °C. Methods Using Poisson-generalized additive models and distributed-lagged nonlinear models, daily mental disorder hospitalizations between 2002 and 2011 in Hong Kong were regressed on daily mean temperature, relative humidity, and air pollutants, adjusted for seasonal trend, long-term trend, day-of-week, and holiday. Analyses were stratified by disease class, gender and age-group. Results 44,600 admissions were included in the analysis. Temperature was positively associated with overall mental-disorder hospitalizations (cumulative relative risk at 28 °C vs. 19.4 °C (interquartile range, lag 0–2 days) = 1.09 (95% confidence interval 1.03, 1.15)), with the strongest effect among the elderly (≥75 years old). Transient mental disorders due to conditions classified elsewhere and episodic mood disorders also showed strong positive associations with temperature. Conclusion This study found a positive temperature–mental-disorder admissions association in a warm subtropical region and the association was most prominent among older people. With the dual effect of global warming and an aging population, targeted strategies should be designed to lower the disease burden.</p