Displaying publications 1 - 20 of 286 in total

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  1. Wong YH, Tan HY, Kasbollah A, Abdullah BJJ, Acharya RU, Yeong CH
    World journal of experimental medicine, 2020 Mar 30;10(2):10-25.
    PMID: 32266125 DOI: 10.5493/wjem.v10.i2.10
    BACKGROUND: Liver cancer is the 6th most common cancer in the world and the 4th most common death from cancer worldwide. Hepatic radioembolization is a minimally invasive treatment involving intraarterial administration of radioembolic microspheres.

    AIM: To develop a neutron-activated, biodegradable and theranostics samarium-153 acetylacetonate (153SmAcAc)-poly-L-lactic acid (PLLA) microsphere for intraarterial radioembolization of hepatic tumors.

    METHODS: Microspheres with different concentrations of 152SmAcAc (i.e., 100%, 150%, 175% and 200% w/w) were prepared by solvent evaporation method. The microspheres were then activated using a nuclear reactor in a neutron flux of 2 × 1012 n/cm2/s1, converting 152Sm to Samarium-153 (153Sm) via152Sm (n, γ) 153Sm reaction. The SmAcAc-PLLA microspheres before and after neutron activation were characterized using scanning electron microscope, energy dispersive X-ray spectroscopy, particle size analysis, Fourier transform infrared spectroscopy, thermo-gravimetric analysis and gamma spectroscopy. The in-vitro radiolabeling efficiency was also tested in both 0.9% sodium chloride solution and human blood plasma over a duration of 550 h.

    RESULTS: The SmAcAc-PLLA microspheres with different SmAcAc contents remained spherical before and after neutron activation. The mean diameter of the microspheres was about 35 µm. Specific activity achieved for 153SmAcAc-PLLA microspheres with 100%, 150%, 175% and 200% (w/w) SmAcAc after 3 h neutron activation were 1.7 ± 0.05, 2.5 ± 0.05, 2.7 ± 0.07, and 2.8 ± 0.09 GBq/g, respectively. The activity of per microspheres were determined as 48.36 ± 1.33, 74.10 ± 1.65, 97.87 ± 2.48, and 109.83 ± 3.71 Bq for 153SmAcAc-PLLA microspheres with 100%, 150%, 175% and 200% (w/w) SmAcAc. The energy dispersive X-ray and gamma spectrometry showed that no elemental and radioactive impurities present in the microspheres after neutron activation. Retention efficiency of 153Sm in the SmAcAc-PLLA microspheres was excellent (approximately 99%) in both 0.9% sodium chloride solution and human blood plasma over a duration of 550 h.

    CONCLUSION: The 153SmAcAc-PLLA microsphere is potentially useful for hepatic radioembolization due to their biodegradability, favorable physicochemical characteristics and excellent radiolabeling efficiency. The synthesis of the formulation does not involve ionizing radiation and hence reducing the complication and cost of production.

    Matched MeSH terms: X-Rays
  2. NUR ATHIRAH ZULKIFLI, MOHD AIDIL ADHHA ABDULLAH, MAZIDAH MAMAT
    MyJurnal
    Polymer had been widely used in industries nowadays. However, the properties of the polymer itself are limited to a particular application. This study describes synthetic clay, layered double hydroxide (LDH), as a filler in low-density polyethylene (LDPE) composite. LDHs of magnesium/aluminium-dodecyl sulfate (Mg/Al-DS) and its grafted with triethoxymethylsilane (TEMS), (TEMS-g-Mg/Al-DS) were synthesized through co-precipitation and salinization reaction methods. The presence of alkyl group, v(C-H) in both LDH had confirmed through Fourier transform infrared (FTIR). The appearance of peaks in FTIR spectra within the absorbance range of 2800 – 2930 cm-1indicates a successful surface modification of LDH, supported by the changes of interlayer spacing and the presence of carbon from X-ray diffractogram and CHNS elemental analysis, respectively. The synthesized LDH was mixed with LDPE via melt intercalation method. The LDH modification resulted in higher interaction and compatibility between the LDPE matrix and LDH by the formation exfoliated type of nanocomposites, as suggested by XRD analysis.
    Matched MeSH terms: X-Rays
  3. Nur Zazarina Ramly, Nor Muhammad Mahadi, Noorul Aini Sulaiman
    Trop Life Sci Res, 2019;30(2):1-14.
    MyJurnal
    Pencirian enzim ekstraselular protease daripada bakteria Alkalophilic Bacillus lehensis G1 dari Malaysia telah dikaji. Enzim protease yang dirembeskan diuji pada agar susu skim 2%. Keputusan menunjukkan protease ekstraselular mampu mengekalkan aktiviti sehingga suhu 60°C di dalam julat pH yang luas iaitu 3 hingga 11 dengan suhu optimum pada 40°C dan pH optimum pada 7.0. Aktiviti enzim juga diperhatikan akan meningkat dengan penambahan beberapa ion iaitu Mn2+, Fe2+, Cu2+, Mg2+ dan Co2+. Manakala aktiviti protease didapati sedikit direncat dengan kehadiran ion Ca2+, K+ dan Ni2+ dengan baki aktiviti sebanyak 85%, 81% dan 75%. Protease ekstraselular juga didapati serasi dengan beberapa cecair detergen komersial dari Malaysia, yang menunjukkan protease ini boleh dimanfaatkan sebagai pembersih kotoran pada pakaian. Selain itu, potensi kegunaan protease yang dihasilkan oleh B. lehensis G1 ke atas penguraian gelatin dari filem X-ray yang telah digunakan juga telah dilakukan di dalam kajian ini.
    Matched MeSH terms: X-Rays
  4. Khan MZ, Ling YS, Yaqoob I, Kumar NN, Kuang LL, San WC
    ScientificWorldJournal, 2014;2014:240729.
    PMID: 25544952 DOI: 10.1155/2014/240729
    A low-energy plasma focus device was used as an electron beam source. A technique was developed to simultaneously measure the electron beam intensity and energy. The system was operated in Argon filling at an optimum pressure of 1.7 mbar. A Faraday cup was used together with an array of filtered PIN diodes. The beam-target X-rays were registered through X-ray spectrometry. Copper and lead line radiations were registered upon usage as targets. The maximum electron beam charge and density were estimated to be 0.31 μC and 13.5 × 10(16)/m(3), respectively. The average energy of the electron beam was 500 keV. The high flux of the electron beam can be potentially applicable in material sciences.
    Matched MeSH terms: X-Rays
  5. Md Noor J, Eddie EA
    Ultrasound J, 2019 Apr 25;11(1):7.
    PMID: 31359168 DOI: 10.1186/s13089-019-0123-x
    BACKGROUND: Traumatic pneumopericardium is rare and usually results from blunt injury. Diagnosis through clinical and chest X-ray is often difficult. Ultrasound findings of A-line artifacts in the cardiac window may suggest pneumopericardium.

    CASE PRESENTATION: A young man involved in a car accident and sustained blunt thoracic injuries, among others. As part of primary survey, FAST scan was performed. Subxiphoid view to look for evidence of pericardial effusion showed part of the cardiac image obscured by A-lines. Other cardiac windows showed only A-lines, as well. A suspicion of pneumopericardium was raised and CT scan confirmed the diagnosis.

    CONCLUSIONS: Although FAST scan was originally used to look for presence of free fluid, with the knowledge of lung ultrasound for pneumothorax, our findings suggest that FAST scan can also be used to detect pneumopericardium.

    Matched MeSH terms: X-Rays
  6. Wan Iskandar WFN, Salim M, Patrick M, Timimi BA, Zahid NI, Hashim R
    J Phys Chem B, 2021 05 06;125(17):4393-4408.
    PMID: 33885309 DOI: 10.1021/acs.jpcb.0c10629
    The lyotropic phase behavior of four common and easily accessible glycosides, n-octyl α-d-glycosides, namely, α-Glc-OC8, α-Man-OC8, α-Gal-OC8, and α-Xyl-OC8, was investigated. The presence of normal hexagonal (HI), bicontinuous cubic (VI), and lamellar (Lα) phases in α-Glc-OC8 and α-Man-OC8 including their phase diagrams in water reported previously was verified by deuterium nuclear magnetic resonance (2H NMR), via monitoring the D2O spectra. Additionally, the partial binary phase diagrams and the liquid crystal structures formed by α-Gal-OC8 and α-Xyl-OC8 in D2O were constructed and confirmed using small- and wide-angle X-ray scattering and 2H NMR. The average number of bound water molecules (nb) per headgroup in the Lα phase was determined by the systematic measurement of the quadrupolar splitting of D2O over a wide range of molar ratio values (glycoside/D2O), especially at high glucoside composition. The number of bound water molecules bound to the headgroup was found to be around 1.5-2.0 for glucoside, mannoside, and galactoside, all of which possesses four OH groups. In the case of xyloside, which has only three OH groups, the bound water content is ∼2.0. Our findings confirmed that the bound water content of all n-octyl α-d-glycosides studied is lower compared to the number of possible hydrogen bonding sites possibly due to the fact that most of the OH groups are involved in intralayer interaction that holds the lipid assembly together.
    Matched MeSH terms: X-Rays
  7. Rodrigues A, Olivato PR, Zukerman-Schpector J, Maganhi SH, Reis AK, Tiekink ER
    J Phys Chem A, 2015 Aug 13;119(32):8714-23.
    PMID: 26213179 DOI: 10.1021/acs.jpca.5b04019
    The X-ray single crystal analysis of isomeric ortho, meta, and para bromo-substituted α-methylsulfonyl-α-diethoxyphosphoryl acetophenones showed that this class of compound adopts synclinal (gauche) conformations for both [-P(O)(OEt)2] and [-S(O)2Me] groups, with respect to the carbonyl functional group. The phosphonate, sulfonyl, and carbonyl functional groups are joined through an intramolecular network of attractive interactions, as detected by molecular orbital calculations at the M06-2X/6-31G(d,p) level. These interactions are responsible for the more stable conformations in the gas phase, which also persist in the solid-state structures. The main structural distinction in the title compounds relates to the torsion angle of the aryl group (with respect to the carbonyl group), which gives rise to different interactions in the crystal packing, due to the different positions of the Br atom.
    Matched MeSH terms: X-Rays
  8. Talebi A, Razali YS, Ismail N, Rafatullah M, Azan Tajarudin H
    Sci Total Environ, 2020 Mar 10;707:134533.
    PMID: 31865088 DOI: 10.1016/j.scitotenv.2019.134533
    An adsorption-desorption process was applied on fermented landfill leachate to adsorb and recover acetic and butyric acid, using activated carbon. In this study, the first, volatile fatty acids adsorption process from fermented leachate was optimized, by investigating various affecting factors such as pH, time, agitation speed, activated carbon dosage, and temperature. The optimum condition for maximum adsorption of 88.94% acetic acid and 98.53% butyric acid, was 19.79 %wt activated carbon dosage, 40.00 rpm of agitation speed, in 9.45 °C and contact time of 179.89 h, while the pH of the substrate was kept fixed at pH:3.0. Results of X-ray fluorescence (XRF) spectrometry, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and zeta potential revealed that carbon is the dominant component in the adsorbent with a significant effect to remove organic impurities, and it was observed that the activated carbon after the adsorption process showed an amorphous structure peak with a large internal surface area and pore volume. The results exposed that the adsorption on the surface of activated carbon was due to the chemisorption, and the chemisorption mechanism was supported by covalent bonding. The kinetic study displayed excellent fit to Pseudo-second order kinetics model. The second phase of this study was to recover the adsorbed VFAs using multistage desorption unit, in which application of deionized water and ethanol (as desorption agents) resulted in 89.1% of acetic acid and 67.8% of the butyric acid recovery.
    Matched MeSH terms: X-Rays
  9. Akinyemi SA, Gitari WM, Petrik LF, Nyakuma BB, Hower JC, Ward CR, et al.
    Sci Total Environ, 2019 May 01;663:177-188.
    PMID: 30711584 DOI: 10.1016/j.scitotenv.2019.01.308
    Coal combustion and the disposal of combustion wastes emit enormous quantities of nano-sized particles that pose significant health concerns on exposure, particularly in unindustrialized countries. Samples of fresh and weathered class F fly ash were analysed through various techniques including X-ray fluorescence (XRF), X-ray diffraction (XRD), focused ion beam scanning electron microscopy (FIB-SEM), field-emission gun scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM) coupled with energy dispersive x-ray spectroscopy (EDS), and Raman Spectroscopy. The imaging techniques showed that the fresh and weathered coal fly ash nanoparticles (CFA-NPs) are mostly spherical shaped. The crystalline phases detected were quartz, mullite, ettringite, calcite, maghemite, hematite, gypsum, magnetite, clay residues, and sulphides. The most abundant crystalline phases were quartz mixed with Al-Fe-Si-K-Ti-O-amorphous phases whereas mullite was detected in several amorphous phases of Al, Fe, Ca, Si, O, K, Mg, Mn, and P. The analyses revealed that CFA-NPs are 5-500 nm in diameter and encapsulate several potentially hazardous elements (PHEs). The carbon species were detected as 5-50 nm carbon nanoballs of graphitic layers and massive fullerenes. Lastly, the aspects of health risks related to exposure to some detected ambient nanoparticles are also discussed.
    Matched MeSH terms: X-Rays
  10. Pan KL, Zulkarnaen M
    Med J Malaysia, 2014 Aug;69(4):197-8.
    PMID: 25500853 MyJurnal
    There is a resurgence of tuberculosis globally but lesions affecting the skull are rare. Cases reported are of single, focal lesions as seen on plain x-rays. We report a 34 yearold patient with tuberculosis of the skull where multiple punched out lesions are seen, mimicking that of multiple myeloma.
    Matched MeSH terms: X-Rays
  11. Izamin I, Rizal AM
    Med J Malaysia, 2012 Dec;67(6):606-9.
    PMID: 23770954 MyJurnal
    INTRODUCTION: Various studies in primary care and hospitalized patients have discouraged routine use of chest x-ray (CXR) in medical examination.
    PURPOSE: The study aims to determine the prevalence of abnormal routine CXR and cost of one CXR at a public health clinic and discuss the rationale of CXR in routine medical examination.
    METHODOLOGY: Data of patients who visited Klinik Kesihatan Bandar Kota Bharu (KKBKB), a public health clinic, from 1 January until 31 December 2010 were examined. The study used cross-sectional design. All patients who came for medical examination and CXR at KKBKB were included. Cost analysis was performed from the perspective of provider.
    FINDINGS: About 63.1% of 8315 CXR films in KKBKB were produced as part of routine medical examination. Prevalence of abnormal CXR was 0.25%. The cost of producing one CXR ranges from RM15.87 to RM32.34.
    DISCUSSION: Low yield from CXR screening and high cost of CXR are the main concern. CXR screening would also lead to unnecessary radiation; and false-positive screening resulting in physical risk, unwarranted anxiety and more expenditure. CXR screening is appropriately reserved for high-risk patients and those with relevant clinical findings.
    Matched MeSH terms: X-Rays
  12. Khairunnisak M, Mohd Khairi MD
    Med J Malaysia, 2014 Dec;69(6):277-8.
    PMID: 25934960 MyJurnal
    We describe the clinical presentation, investigation and management of an eventually fatal case of hypercalcemic crisis due to primary hyperparathyridism (PHPT). A 60 year-old lady with history of urolithiasis presented with worsening generalized bone pain, spinal scoliosis and a limp. Laboratory data showed hypercalcemia and raised alkaline phosphatase. Left hip x-ray revealed a subcapital femoral neck fracture. Intact parathyroid hormone was elevated, 187.6 pmol/L (1.6 - 6.9) and ultrasound showed an enlarged right parathyroid gland. Despite initial reduction of serum calcium with saline infusion and multiple doses of intravenous pamidronate, her calcium increased to 4.14 mmol/L a week following application of Buck's traction for persistent left hip pain. She succumbed eventually with serum calcium peaking at 6.28 mmol/L despite multiple therapeutic interventions.
    Matched MeSH terms: X-Rays
  13. Mohd Firdaus MAB, Zulkafli H, Said MR, Hadi MF, Sukhari S, Arjan Singh RS
    Med J Malaysia, 2020 11;75(6):750-751.
    PMID: 33219192
    Pseudotumour of the lung is a rare chest x-ray finding among patients who present with fluid overload. It is caused by loculated pleural effusion in the lung fissures. Unfortunately, the occurrence of pseudotumour can be misleading and sometimes can lead to unnecessary investigation and emotional stress to the patient. We present here a case of a 61-year-old gentleman with a known history of hypertension, diabetes mellitus and dyslipidemia who presented at University Malaya Medical Centre with symptoms of fluid overload and a right middle lobe mass on chest x-ray. The right middle lobe mass disappeared entirely after being treated with aggressive diuretic therapy. A diagnosis of pseudotumour was made and described in this case report.
    Matched MeSH terms: X-Rays
  14. Sachithanandan A, Lockman H, Azman RR, Tho LM, Ban EZ, Ramon V
    Med J Malaysia, 2024 Jan;79(1):9-14.
    PMID: 38287751
    INTRODUCTION: The poor prognosis of lung cancer has been largely attributed to the fact that most patients present with advanced stage disease. Although low dose computed tomography (LDCT) is presently considered the optimal imaging modality for lung cancer screening, its use has been hampered by cost and accessibility. One possible approach to facilitate lung cancer screening is to implement a risk-stratification step with chest radiography, given its ease of access and affordability. Furthermore, implementation of artificial-intelligence (AI) in chest radiography is expected to improve the detection of indeterminate pulmonary nodules, which may represent early lung cancer.

    MATERIALS AND METHODS: This consensus statement was formulated by a panel of five experts of primary care and specialist doctors. A lung cancer screening algorithm was proposed for implementation locally.

    RESULTS: In an earlier pilot project collaboration, AI-assisted chest radiography had been incorporated into lung cancer screening in the community. Preliminary experience in the pilot project suggests that the system is easy to use, affordable and scalable. Drawing from experience with the pilot project, a standardised lung cancer screening algorithm using AI in Malaysia was proposed. Requirements for such a screening programme, expected outcomes and limitations of AI-assisted chest radiography were also discussed.

    CONCLUSION: The combined strategy of AI-assisted chest radiography and complementary LDCT imaging has great potential in detecting early-stage lung cancer in a timely manner, and irrespective of risk status. The proposed screening algorithm provides a guide for clinicians in Malaysia to participate in screening efforts.

    Matched MeSH terms: X-Rays
  15. Danaraj TJ
    Med J Malaya, 1947;4:278-288.
    Eight caaes of this condition are described, the patients being four Ceylonese, three Indians, and one Chinese, all males except one. Symptoms consisted of breathlessness and cough, sputum being sometimes purulent and occasionally blood-stained. Six of the patients complained of loss of weight, and in one, a Ceylonese schoolboy, this was the only presenting symptom. The authors found the most troublesome complaint to be a paroxysmal cough which was always worst at night. On clinical examination rhonchi were heard scattered throughout both lung fields in five cases, the lungs being clear in the other three. X-ray examination showed characteristic mottling of both lungs in four cases and of one lung in one case; another showed increased vascular markings, while in two the lungs were clear. Sputum was examined for tubercle bacilli and mites but none were found. The technique used for searching for mites is not described. A marked eosinophilia was found in all cases, the highest count recorded being 33, 264 eosinophils per cmm.Treatment consisted of arsenic, given in the form of neoarsphenamine, six injections of 0.3 gm. in six cases, and stovarsol 4 grains t.d.s. for seven and ten days respectively in the other two. Four of the patients were cured, three were improved, while one was showing a favourable response although treatment had not been completed.The author emphasizes the importance of performing repeated blood counts in order to avoid missing this condition. Out of the eight cases which he describes, one had been wrongly diagnosed as pulmonary tuberculosis and three as bronchial asthma. One of the latter had an initial eosinophil count of 4, 092 which rose to 17, 700 three weeks later. H. T. H. Wilson
    Matched MeSH terms: X-Rays
  16. Dolah MT, Samat SB, Kadni T
    Malays J Med Sci, 2000 Jan;7(1):47-53.
    PMID: 22844215
    Absorbed dose to water was measured with ionisation chambers NE 2561 (#267), NE 2581 (#334), NE 2571 (#1028), using the IAEA standard water phantom. The ionisation chamber was inserted in the water phantom at a reference depth dependent on the type of the radiation quality used. Three radiation qualities were used namely 1.25 MeV gamma ray, 6 MV x-rays and 10 MV x-rays. The values of the absorbed dose to water were determined by the N(K)- and N(X)- based methods, i.e with the use of IAEA, HPA, NACP, AAPM, NCRP and ICRU protocols. The aim of this study was to make an intercomparison of the results, by taking the IAEA protocol as a standard. The largest deviation contributed by any of these protocols was recorded for each quality. It was found that AAPM, NCRP and ICRU protocols contributed 0.94% for 1.25 MeV gamma ray, NACP contributed 2.12% for the 6 MV x-rays, and NACP contributed 2.35% for 10 MV x-rays. Since the acceptable limit of deviation set by the IAEA for this absorbed dose work is ± 3%, it is clear that the overall deviations obtained were all satisfactory.
    Matched MeSH terms: X-Rays
  17. Jalal TMT, Abdullah S, Wahab FA, Dir S, Naing NN
    Malays J Med Sci, 2017 Dec;24(6):75-82.
    PMID: 29379389 DOI: 10.21315/mjms2017.24.6.9
    Background: One of the six strategies developed by WHO, in order to stop Tuberculosis (TB) is addressing TB/HIV high-risk groups. This study aimed to determine the prevalence of successful TB treatment and factors associated with TB treatment success among TB/HIV co-infection patients in North-East Malaysia.
    Methods: A cross-sectional study was carried out in the a-year period from 2003 to 2012 by reviewing TB/HIV records in all hospitals and health clinics. The outcome of interest was treatment success as defined by Ministry of Health (MOH) when the patients was cured or completed TB treatment.
    Results: Out of 1510 total TB/HIV co-infection cases, 27.9% (95% CI: 25.2, 30.6) of the patients were having treatment success. A majority of TB/HIV co-infection cases were male (91.1%). Fifty-eight percent the patients were drug addicts and 6% were having positive tuberculin tests. The multiple logistic regression revealed that male (OR: 0.39, 95% CI: 0.22, 0.71) and positive tuberculin test result (OR: 2.61, 95% CI: 1.63, 4.19) were significantly associated with the treatment success of TB/HIV co-infection patients. Other factors such as age, comorbid, sputum smear and x-ray findings were not significantly factors in this study.
    Conclusion: Female patients and those with negative tuberculin test should be emphasised for successful tuberculosis treatment.
    Matched MeSH terms: X-Rays
  18. Chen SC, Jong WL, Harun AZ
    Malays J Med Sci, 2012 Jul;19(3):22-8.
    PMID: 23610546 MyJurnal
    Different computational methods have been used for the prediction of X-ray spectra and beam quality in diagnostic radiology. The purpose of this study was to compare X-ray beam qualities based on half-value layers (HVLs) determined through measurements and computational model estimations.
    Matched MeSH terms: X-Rays
  19. Das BK, Biswal BM, Bhavaraju M
    Malays J Med Sci, 2006 Jan;13(1):52-7.
    PMID: 22589591 MyJurnal
    X-ray mammography has been the backbone of early detection of breast cancer. Several large scale systematic studies have shown that judicious use of X-ray mammography can indeed save life. However, though reasonably sensitive, X-ray mammography lacks in specificity leading to many unnecessary biopsies. Scintimammography is a relatively new imaging method to demonstrate cancer tissue in the breast. A radiopharmaceutical agent (Tc-99m Sestamibi) is administered intravenously and images of the breast are taken under a Gamma Camera. There is no need for any manipulation like compression of the breast as required to be done during mammography. The radiopharmaceutical accumulates in the breast in the presence of cancer tissue which can easily be seen in the images. The affinity of the cancer tissue to this radiopharmaceutical is up to 9 times in comparison to normal breast tissue. Several multi centric studies with blinded image interpretation have established the sensitivity and specificity of scintimammography to be above 85 and 90 % respectively as compared to 89 and 14 % respectively for X-ray mammography. The positive and negative predictive values of scintimamography are 70 and 83 % as against 49 and 57 % respectively for X-ray mammography. With the increasing availability of Nuclear Medicine facilities it is expected that more and more patients will benefi with the use of this new imaging modality .
    Matched MeSH terms: X-Rays
  20. Van Wassenbergh S, Joris I, Desclée M, Liew HJ, De Boeck G, Adriaens D, et al.
    J Exp Biol, 2016 05 15;219(Pt 10):1535-41.
    PMID: 27207955 DOI: 10.1242/jeb.131631
    Many species from several different families of fishes perform mouthbrooding, where one of the sexes protects and ventilates the eggs inside the mouth cavity. This ventilation behaviour differs from gill ventilation outside the brooding period, as the normal, small-amplitude suction-pump respiration cycles are alternated with actions including near-simultaneous closed-mouth protrusions and high-amplitude depressions of the hyoid. The latter is called churning, referring to its hypothetical function in moving around and repositioning the eggs by a presumed hydrodynamic effect of the marked shifts in volume along the mouth cavity. We tested the hypothesis that churning causes the eggs located posteriorly in the mouth cavity to move anteriorly away from the gill entrance. This would prevent or clear accumulations of brood at the branchial basket, which would otherwise hinder breathing by the parent. Dual-view videos of female Nile tilapias (Oreochromis niloticus) during mouthbrooding showed that churning involves a posterior-to-anterior wave of expansion and compression of the head volume. Flow visualisation with polyethylene microspheres revealed a significant inflow of water entering the gill slits at the zone above the pectoral fin base, followed by a predominantly ventral outflow passing the ventrolaterally flapping branchiostegal membranes. X-ray videos indicated that particularly the brood located close to the gills is moved anteriorly during churning. These data suggest that, in addition to mixing of the brood to aid its oxygenation, an important function of the anterior flow through the gills and buccal cavity during churning is to prevent clogging of the eggs near the gills.
    Matched MeSH terms: X-Rays
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