Phase-mismatch dependence of the four-wave mixing effect in semiconductor optical amplifiers.

The phase-mismatch effect due to polarization-dependent mode confinement factor has been shown to be not a crucial problem in semiconductor optical amplifiers (SOAs) and is usually not accounted for. The phase-mismatch four-wave mixing (FWM) process in SOA devices is experimentally reported. The results reveal a sinc-like behavior in the intensity of FWM conjugate as a function of wavelength separation between transverse electric (TE)/transverse magnetic (TM) pumps due to induced confinement factors difference. Efficient FWM occurred for a detuning shift of about 500 GHz, limited by phase-mismatch conditions and determined by coherence length required for low and high frequencies to complete a full phase-match cycle. Phase-match FWM with an infinity coherence length can be fulfilled by proper alignments of co-polarized TE/TM modes of input waves with respect to the birefringent axes of the device structure.

Effects of Bauxite and Alumina Exposure on Incidence of Cancer - Meta-analysis.

Bauxite is an ore from which Aluminium is produced. Malaysia, once the leading producer of bauxite has reduced production as mining activity has caused community outrage. Due to concerns about health concerns, rising pollution and environmental hazards, the government has revoked the licenses of bauxite miners. We therefore did a meta-analysis to assess the relationship between exposure to Bauxite and Alumina with incidence of various types of cancers. Bauxite mines and alumina refineries. Individuals of all ages exposed to Bauxite and Alumina. Exposure to bauxite and alumina. Incidence due to overall cancers and specific types of cancers. Exposure to bauxite and alumina did not cause variations in incidence of overall cancer and specific types of cancer such as cancer of lip, cancer of the oral cavity and pharynx, cancer of digestive organs and others. We conclude that there is no evidence that bauxite or alumina exposure cause increase incidence of cancer but due to the small number of studies included in this review, we recommend more cohort studies to be done in future.

Towards Vision 2020 -Trends of Cataract Surgery in Melaka Hospital, A Malaysian Tertiary Center: 2007-2014.

Background Cataract surgery which is the only scientific method to treat cataracts has evolved from large incisions of intracapsular cataract excision to extracapsular cataract exicison and now modern day phacoemulsification. Anaesthesia too has progressed from general anaesthesia to local and topical anaesthesia. A variety of intraocular lenses are available ranging from rigid to foldable, multifocal and toric. Day care surgeries are becoming the norm these days. Objective Cataract surgery has advanced with new techniques and modalities. We studied the trends of cataract surgery and outcomes over the years. Method We performed secondary data analysis (National Eye Database) of cataract surgery patients in Hospital Melaka (2007 - 2014). Result Most patients were 60-69 years (mean 65.0 years). Primary cataract rose (p<0.05) but there was no difference in laterality and first or second eye (p>0.05). More patients presented with Hypertension and Diabetes (p<0.05). Pterygium encroaching the cornea showed a rise (p<0.05). Phacoemulsification (80.8%) showed a rise while Extracapsular Cataract Extraction (ECCE) (15.4%) declined (p<0.05). More Specialists operated and fewer combined surgeries were performed (p<0.001). Type of anaesthesia did not change (p>0.05). Operative complications reduced (p<0.001). Anterior chamber, scleral fixated and foldable intraocular lenses usage reduced (p<0.05). There was no change in pre-operative visual acuity (p>0.05) but postoperative vision showed a rise in good outcomes (p<0.05). Conclusion Melaka Hospital shows a rise in phacoemulsification and a decline in Extracapsular Cataract Extraction. More patients presented with primary cataracts. More Specialists operated and there was a reduction in intraoperative and postoperative complications. Post-operative visual outcomes showed a remarkable improvement. This improvement is in keeping with the aim of improved vision for all by 2020.

Wide-uniform triple Brillouin frequency spacing multi-wavelength fiber laser assisted by a distributed Raman amplifier.

In this paper, we demonstrate a wide-uniform and hybrid multi-wavelength fiber laser source with triple Brillouin-shift wavelength spacing. The hybrid gains include the combination of erbium-ytterbium-doped fiber and distributed Raman amplifiers. For optimum performances, the Brillouin pump wavelength is set at 1532 nm with power at -20 dBm, erbium-ytterbium-doped fiber amplifier at 950 mW and Raman pump power at 900 mW. The highest channel count is obtained in this kind of laser design, where around 164 Stokes lines are produced within 10 dB spectral flatness. The corresponding bandwidth is 40 nm, where the average optical signal-to-noise ratio is maintained at 36 dB estimation. The outstanding total power stability indicates 0.74 dB fluctuation over a 45-minute duration. This merits the practicality for various applications especially in optical communication system and sensing. Furthermore, a reasonable wide tuning range of 36 nm is realized, beginning from 1532 nm, which is only restricted by the accessible hybrid gain bandwidth.

Cataract Surgery Incidence Trends in a Tertiary Public Hospital in Malaysia.

Background Since cataract is the leading cause of blindness and no study has been done on the surgical incidence trends, we conducted this research in Melaka. Objective To describe incidences of cataract surgery according to basic demographic variables and types of surgery performed. Method Using the National Eye Database (NED), we performed descriptive statistics calculating incidence rates per 1,000 population by demographic features and types of cataract operations to look at the trends of surgeries in the population. Statistics for population were obtained from the department of statistics. Result From 2007-2010, 6270 patients mostly 60-69 years underwent cataract surgery. Phacoemulsification (78.2%) was the commonest surgery performed. The annual incidence rate of cataract surgery reduced from 2.05 per 1000 population in 2007 to 2.02 per 1000 population in 2010 (p<0.05). Incidence rates for those aged 60 and above rose while for those aged below nine years it declined. Indians had the highest incidence rates followed by Chinese and Malays per 1000 population. Females had a higher incidence rate although there was a declining trend over the years. Conclusion Cataract surgery rates showed a decline. Public health education and awareness on detection and operating upon cataracts should be increased and especially targeted towards vulnerable groups such as women, individuals of Indian ethnicity and those aged 50 years and above.

Enhanced flatness of 20 GHz channel spacing multiwavelength Brillouin-Raman fiber laser with sub-millimeter air gap.

We discover the technique of controlling the flatness in signal amplitude of a multiwavelength Brillouin-Raman fiber laser by employing an air-gap outside of the cavity. The structure that is adjustable within sub-millimeter length behaves as flexible optical feedback that provides modifiable portions of multiple Fresnel reflectivities. This is the main benchmark that allows the efficient management of gain competition between self-lasing modes and Brillouin Stokes waves that is vital for self-flattening initiation. When setting the Brillouin pump wavelength at 1529 nm and the air-gap distance to 0.4 mm, 296 Stokes lines are produced with a channel spacing of 0.158 nm. The lasing bandwidth is 46.60 nm that covers from 1529.16 to 1575.76 nm wavelength. In this case at Raman power of 950 mW, the intense Brillouin pump power of 2 dBm saturates the cascaded higher-orders lasing lines. As a result, the overall peak power discrepancy is maintained at just 1.8 dB where an average optical-signal-to-noise ratio of 20 dB is realized. To date, this is the widest bandwidth with the flattest spectrum attained in multiwavelength fiber lasers that incorporate a single Raman pump unit.

Wide bandwidth and flat multiwavelength Brillouin-erbium fiber laser.

A wide bandwidth and flat multiwavelength Brillouin-erbium fiber laser is demonstrated experimentally. In the proposed laser setup, the combination of a Brillouin mirror with feedback and a ring cavity with four-wave mixing assistance is realized. The efficiency of Brillouin Stokes lines generation is enhanced by the feedback-based Brillouin mirror structure. The effect of four-wave mixing in highly nonlinear fiber increases the generation of Brillouin Stokes lines in a wider bandwidth. The laser lines over 16 nm bandwidth (i.e 200 channels) within 4.65 dB power difference are obtained. The generated laser lines span from 1534 to 1550 nm with wavelength spacing of 0.08 nm and optical signal-to-noise ratio of at least 15 dB. The laser can also be freely tuned over 32 nm and is stable with power fluctuations of 0.7 dB over 1 hour duration.

[Influence on Strychni Semen's Analgesic Effect and Toxicity of Milk-Impregnated- Processing-Technology of Traditional Uighur Medicine].

OBJECTIVE: To investigate the effects of different processing methods on analgesic effect and toxicity of Strychni Semen, and to provide the scientific basis of milk-impregnated-processing-technology of traditional Uighur medicine for toxic medicines. METHODS: Three different methods, frying with sand of traditional Chinese medicine (1), cooled milk-impregnated-processing-technology of traditional Uighur medicine (2), and heated milk-impregnated-processing-technology of traditional Uighur medicine (3) were used to process raw Strychni Semen and the processed products were compared with those in the raw drug (4). Karber method was used to caculate the LD50. RESULTS: The LD50 of (4), (1), (2) and (3)were 273.0, 289.3, 289.3 and 339.2 mg/kg,successively. Low dose group of heated milk-impregnated-processing-technology, low and high dose groups of cooled milk-impregnated-processing-technology had significant inhibition on the acetic acid-induced writhing reaction in mice (P < 0.05). CONCLUSION: Strychni Semen processed by cooled and heated milk can enhance the analgesic effect in mice while improving the LD50 of mouse, which illustrates milk-impregnated-processing- technology's pharmacological mechanism on efficacy enhancing and toxicity reducing of Strychni Semen.

Academic Staff Perspectives Towards Adoption of E-learning at Melaka Manipal Medical College: Has E-learning Redefined our Teaching Model?

BACKGROUND: E-learning is the use of Information and Communication Technology (ICT) to provide online education and learning. E- Learning has now been integrated into the traditional teaching as the concept of 'blended learning' that combines digital learning with the existing traditional teaching methods to address the various challenges in the field of medical education. Structured e-learning activities were started in Melaka Manipal Medical College in 2009 via e-learning platform (MOODLE-Modular Object-Oriented Dynamic Learning Environment). OBJECTIVES: The objective of the present study is to investigate the faculty opinions toward the existing e-learning activities, and to analyse the extent of adopting and integration of e-learning into their traditional teaching methods. METHODS: A cross sectional study was conducted among faculties of Medicine and Dentistry using pre-tested questionnaires. The data was analyzed by using the statistical package for social science, SPSS, version 16.0. RESULTS: The result of our survey indicates that majority of our faculty (65.4%) held positive opinion towards e-learning. Among the few, who demonstrated reservations, it is attributed to their average level of skills and aptitude in the use of computers that was statistically significant (p<0.05). CONCLUSION: Our study brings to light the need for formal training as perquisite to support e-learning that enables smooth transition of the faculty from their traditional teaching methods into blended approach. Our results are anticipated to strengthen the existing e-learning activities of our college and other universities and convincingly adopt e-learning as a viable teaching and learning strategy.

20 GHz spacing multi-wavelength generation of Brillouin-Raman fiber laser in a hybrid linear cavity.

We demonstrate a tunable multi-wavelength Brillouin-Raman fiber laser with 20 GHz wavelength spacing. The setup is arranged in a linear cavity by employing 7.2 and 11 km dispersion compensating fibers (DCF) in addition to a 30 cm Bismuth-oxide erbium doped fiber. In this experiment, for the purpose of increasing the Stokes lines, it is necessary to optimize Raman pump power and Brillouin pump power together with its corresponding wavelengths. At the specific Brillouin pump wavelength, it is found that the longer length of 11 km DCF with optimized parameters results in larger number of Stokes combs and optical signal to noise ratios (OSNRs). In this case, a total of 195 Brillouin Stokes combs are produced across 28 nm bandwidth at Brillouin pump power of -2 dBm and Raman pump power of 1000 mW. In addition, all Brillouin Stokes signals exhibit an average OSNR of 26 dB.

Multiwavelength Brillouin fiber laser with enhanced reverse-S-shaped feedback coupling assisted by out-of-cavity optical amplifier.

A multiwavelength widely tunable Brillouin optical comb with an enhanced reverse-S-shaped feedback coupling assisted by out-of-cavity optical amplifier is demonstrated. The enhancement is done by locating the amplifier and the Brillouin pump into the reverse-S-shaped fiber section. The oscillating modes in the cavity are directly influenced solely by the Brillouin gain. A wide tuning range of 45 nm is obtained that is only limited by the erbium amplification bandwidth. An average of eleven laser lines that can be tuned to over 45 nm wavelengths is obtained at 40% optimum output coupling ratio.

[Ménétrier's disease of childhood and acute cytomegalus virus infection]. / Enfermedad de Ménétrier infantil e infección aguda por citomegalovirus.

Menetrier's disease of childhood, or protein-losing hypertrophic gastropathy, is a rare entity of unknown etiology, characterized by hypertrophy of the gastric mucosa as well as secondary protein loss. Most published cases are associated with infection, mainly viral. These infections could alter the factors regulating growth and the function of gastric cells. In children, the disease is mild and resolved within a few weeks. We present the case of a 15-month-old child with a 72-hour history of intractable vomiting, hypoproteinemia and generalized progressive edema. We describe the characteristics of this case, as well as the clinical, ultrasonographic and endoscopic findings required for a diagnosis of this disease.

Occupational radiation exposure to anesthetists from fluoroscopic projections during orthopedic operative procedures.

PURPOSE: The role of anesthetists during orthopedic fluoroscopic procedures exposes them to radiation. We conducted a prospective, descriptive study to estimate the radiation exposure to anesthetists during procedures over a six-month period in the orthopedic trauma operating theatres which had the most fluoroscopic usage. MATERIALS AND METHODS: Thermoluminescent dosimeter (TLD) chips were placed two metres away from the radiation source, in three positions to simulate the anesthetist's position in the operating theatre during the fluoroscopic procedures as well as their radiation safety practices. The three positions were above the lead gown, behind the lead gown and behind the protective lead screen. The fourth TLD chip was assigned as a control measure to account for background radiation. The radiation exposure was measured at every end of each month during the period of six consecutive months. The TLD chips were sent to the Malaysian Institute for Nuclear Technology (MINT) for the analysis. RESULTS: From the study, the annual exposure without a protective shield at a 2 metre distance from the projection source was estimated to be 0.70 milliSievert (mSv)/year. With the use of lead gowns and protective lead screens, the annual exposure was estimated to be 0.08 mSv / year. All the radiation levels measured were within the maximum permissible dose of 50 mSv / year. CONCLUSIONS: During fluoroscopic assisted orthopedic procedures, the anesthetists in UKMMC are exposed to a small amount of radiation which is well below the annual maximum permissible limit as determined by local and international regulatory bodies.

Effect of cardiac rehabilitation program on exercise capacity in women undergoing coronary artery bypass graft in hamadan-iran.

OBJECTIVES: The purpose of this study was to determine the effects of cardiac rehabilitation program (CRP) on exercise capacity and rate pressure product (RPP) in Iranian female patients undergoing coronary artery bypass grafting (CABG) in Hamadan, Iran. METHODS: Sixty women after CABG were assigned into an exercise group (n = 30, mean age 58.5 ± 10.8 years), who performed physical training for 12 weeks, or a control group (n = 30, mean age 59.3 ± 8.6 years) who received usual care. Functional capacity and RPP were evaluated by six minute walking test (6MWT) and exercise test. RESULTS: In comparison to before training, significant increases of estimated exercise capacity (10.72 ± 1.30 vs. 7.72 ± 1.6 MET's, respectively) as well as 6MWT (556 ± 66.1 vs. 375.2 ± 28.1 meters, respectively) were observed in exercise group after 12 weeks training (P<0.001). Women increased their exercise duration time (464.6 ± 107.3 vs. 311.2 ± 101.7 seconds, respectively) by 49.2% and RPP (22361 ± 3206 vs. 20270 ± 2704.1, respectively) by 10.3% after training (P<0.001). However, no significant differences were found before and after CRP in the control group. CONCLUSIONS: Women referred for rehabilitation have similar levels of compliance and improvement in exercise capacity and supply of oxygen to cardiac muscles (measured by peak myocardial oxygen consumption). After CRP, women demonstrated significant improvements in exercise duration time, 6MWT, RPP and supply of oxygen to cardiac muscles. CRP can play an important role in improving functional independence in women.

Single-dose oral fluconazole versus topical clotrimazole in patients with pityriasis versicolor: A double-blind randomized controlled trial.

This study was designed to compare the therapeutic effects of topical clotrimazole and systemic fluconazole in pityriasis versicolor. A double-blind randomized controlled trial was carried out in the dermatological clinic of Gorgan, northern Iran, between April 2006 and May 2007. All consecutive patients with pityriasis versicolor were included and randomly divided into two groups. In the first group (G1), patients underwent treatment with a single dose of fluconazole capsule (400 mg) and placebo cream. In the second group (G2), patients underwent treatment with clotrimazole cream (twice daily) and placebo capsule. The course of treatment was 2 weeks. All subjects were re-evaluated 2, 4 and 12 weeks after the end of the therapeutic course. After 2 weeks, the rate of complete resolution of disease was significantly higher in G2 than G1 (49.1% vs 30%). After 4 weeks, 41 patients (81.2%) of G1 and 52 patients (94.9%) of G2 showed complete resolution. After 12 weeks, 46 patients (92%) in G1 and 45 patients (81.8%) in G2 showed complete resolution. Recurrence rate in G1 and G2 were 6% and 18.2%, respectively. No complications were seen in either group. In this study, clinical response at week 4 was greater in the clotrimazole group than the fluconazole group. Recurrence at week 12 after treatment was less with oral fluconazole than clotrimazole cream. So, for better evaluation, more studies need to be done.

Molecular characterization of rotavirus gastroenteritis strains, Iraqi Kurdistan.

Of 260 children with acute diarrhea in Erbil, Iraqi Kurdistan, 96 (37%) were infected with rotavirus. Reverse transcription-polymerase chain reaction identified G1, G4, G2, G9, P[8], P[6], and P[4] as the most common genotypes. Eight G/P combinations were found, but P[8]G1 and P[4]G2 accounted for >50% of the strains.

Enantioselective disposition of 2-arylpropionic acid nonsteroidal anti-inflammatory drugs. IV. Ketoprofen disposition.

The disposition of ketoprofen enantiomers has been studied in 12 rabbits with normal renal function (control) and in 6 of these rabbits with renal dysfunction. In control animals a mean (S.E.M.) of 0.09 (0.01) of R-ketoprofen was inverted to its S-enantiomer. The mean distribution volumes for R- and S-ketoprofen were 114 (7.4) and 294 (76) ml/kg, respectively. The mean clearance of the R-enantiomer from plasma was 292 (40) ml/kg/hr compared to 36 (3.2) ml/kg/hr for the S-enantiomer. This high degree of enantioselectivity was not due to inversion, renal clearance or clearance by glucuronidation, but was the result of an unknown clearance process(es). Comparing the mean parameters of ketoprofen disposition in renal dysfunction with those in the same animals during the control study, the mean fraction of the R-dose inverted increased by 290%, but this effect was not due to decreased clearance of R-ketoprofen renally or by glucuronidation. The distribution volumes of R- and S-ketoprofen were increased by 200 and 183% by renal dysfunction, consistent with an implied decrease in plasma protein binding. The clearances of bound plus unbound R- and S-ketoprofen from plasma remained unaltered by renal dysfunction.

Effect of chronic angiotensin-converting enzyme blockade on pressor responses to exogenous angiotensin II, noradrenaline and vasopressin in deoxycorticosterone acetate salt (DOCA)-induced hypertensive rats.

Effect of chronic angiotensin converting enzyme blockade on the pressor response to exogenous angiotensin II, noradrenaline and vasopressin were evaluated in DOCA-salt induced hypertensive rats using teprotide. The blood pressure of rats receiving teprotide chronically was reduced markedly. The pressor responses to exogenous angiotensin II was accentuated, while that of noradrenaline and vasopressin were significantly reduced. It is concluded that besides the angiotensin converting enzyme blocking action, the decrease in sensitivity of the pressor response to noradrenaline and vasopressin may contribute towards the antihypertensive activity of teprotide given chronically.

Maternal contamination of amniotic fluid demonstrated by DNA analysis.

DNA from 16 sets of samples comprising DNA from uncultured amniotic fluid cells, cultured amniotic fluid cells, fetal tissue, and maternal blood was analysed by the polymerase chain reaction (PCR) with AC-repeat primers. The analysis was performed to investigate the presence of contaminating maternal cells in amniotic fluid which would affect the reliability of DNA studies for prenatal diagnosis. In three sets, maternal contamination of uncultured amniotic fluid cells was detected. In one of the three sets, maternal contamination was present in both uncultured and cultured amniotic fluid cells. The use of amniotic fluid cells as a source of DNA for prenatal diagnosis should be limited to cases where the purity of the DNA can be demonstrated prior to the diagnostic test being performed. This limitation in the use of amniotic fluid DNA also extends to other forms of diagnosis relying on the purity of amniotic fluid samples, particularly the new in situ hybridization methods currently being developed.