Occurrence and germination of dinoflagellate cysts in surface sediments from the Red Sea off the coasts of Saudi Arabia

AbstractThe distribution and abundance of dinoflagellate cyst assemblages were investigated in surface sediments from south-western Red sea coasts of Saudi Arabia at six sites during March 2010. A total of 19 taxa of dinoflagellate cysts were identified from all sites. The sampling sites showed a similar cyst assemblage, but they differed in total cyst abundance (3 to 4083 cysts g−1 dry weight). Cyst abundance was strongly correlated with sediment characteristics, the highest numbers being recorded in sediments with large contents of organic carbon, silt and clay. Cyst assemblages were dominated by cysts of potentially toxic species, including Cochlodinium polykrikos, Prorocentrum minimum, Dinophysis acuminata, Alexandrium catenella and Scrippsiella trochoidea. Most cysts germinated successfully at different rates at 15 and 25° C. This study suggests that surface sediments from all Saudi Red Sea coasts should be monitored for the presence of dinoflagellate cysts to give ample warning of the presence and abundance of toxic species in a given area

Direct Enantiomeric Resolution of Betaxolol with Application to Analysis of Pharmaceutical Products

A high-performance liquid chromatographic (HPLC) method has been developed for the separation and determination of S- and R-enantiomers of betaxolol in tablets and ophthalmic preparations. Baseline resolution was achieved by using teicoplanin macrocyclic antibiotic chiral stationary phase (CSP) known as Chirobiotic T with fluorescence detection at excitation/emission wavelengths 275/305 nm. The polar ionic mobile phase (PIM) consists of methanol-glacial acetic acid-triethylamine, (100:0.020:0.025, v/v/v) has been used at a flow rate of 1.5 ml/min. All analytes with S-(–)-atenolol as internal standard were conducted at ambient temperature. The method is highly specific where another coformulated compounds did not interfere. The stability of betaxolol enantiomers under different degree of temperature also studied. The results showed that it is stable for at least 7 days at 70°C. The method validated for its linearity, accuracy, precision and robustness. Experimental design was used during validation to evaluate method robustness. Using the chromatographic conditions described, S- and R-betaxolol were well resolved with mean retention times of 11.3 and 12.6 min, respectively. Linear response (r > 0.997) was observed over the range of 10–500 ng/ml of betaxolol enantiomers, with detection limit of 5 ng/ml. The recoveries of S- and R-betaxolol from tablets and ophthalmic preparation ranged from 97.4 to 101.4% and 98.0 to 102.0%, respectively. The mean relative standard deviation (R.S.D.%) for both enantiomers were 1.1–1.4% and 1.3–1.7% in tablets and ophthalmic solution, respectively

Retrospective study of endoscopic nasal septoplasty

Abstract This is a retrospective review of data of 70 patients who underwent endoscopic nasal septoplasty . The case records of 70 patients who underwent endoscopic septoplasty during the period from January 2009 to December 2011 at the Saudi German Hospital, Aseer Region, Kingdom of Saudi Arabia were reviewed. Patients had septal deviation and symptomatic nasal obstruction for at least 3 months, and medical management had failed. Preoperatively, nasal endoscopic findings were septum deviations (34 patients, 48.6%), spurs (30 patients, 42.9%) and septum deviations + spurs (6 patients, 8.6%). The most common presenting symptoms were nasal obstruction (55 patients, 78.6%), headache (42, 60%) and posterior nasal discharge (34, 48.6%), which improved significantly postoperatively. After the end of the follow up period of 6 months, there were no recorded immediate or late postoperative complications among all patients. Endoscopic nasal septoplasty is an effective technique that can be performed safely with a significant postoperative improvement in patient's symptoms and minimal or no postoperative complications

Design and performance evaluation of bitwise retransmission schemes in wireless sensor networks

The previously proposed bitwise retransmission schemes which retransmit only selected bits to accumulate their reliability are designed and evaluated. Unlike conventional automatic repeat request (ARQ) schemes, the bitwise retransmission schemes do not require a checksum for error detection. The bitwise retransmission decisions and combining can be performed either after demodulation of the received symbols or after channel decoding. The design and analysis assume error-free feedback, however, the impact of feedback errors is also considered. The bit-error rate (BER) expressions are derived and verified by computer simulations in order to optimize the parameters of the retransmission schemes. The BER performance of coded and uncoded bitwise retransmissions is compared with a hybrid ARQ (HARQ) scheme over additive white Gaussian noise (AWGN), slow fading, and fast fading channels. It is shown that bitwise retransmissions outperform block repetition coding (BRC) over AWGN channels. In addition, the selection diversity created by the bitwise retransmissions can outperform the HARQ at large signal-to-noise ratio (SNR) over fast fading channels. Finally, the practical design of a bitwise retransmission protocol for data fusion in wireless sensor networks is presented assuming Zigbee, WiFi and Bluetooth system parameters

Divorce and Severity of Coronary Artery Disease: A Multicenter Study

The association between marital status and coronary artery disease (CAD) is supported by numerous epidemiological studies. While divorce may have an adverse effect on cardiac outcomes, the relationship between divorce and severe CAD is unclear. We conducted a multicenter, observational study of consecutive patients undergoing coronary angiography during the period between April 1, 2013, and March 30, 2014. Of 1,068 patients, 124 (12%) were divorced. Divorce was more frequent among women (27%) compared to men (6%). Most divorced patients had been divorced only once (49%), but a subset had been divorced 2 (38%) or ≥3 (12%) times. After adjusting for baseline differences, there was no significant association between divorce and severe CAD in men. In women, there was a significant adjusted association between divorce and severe MVD (OR 2.31 [1.16, 4.59]) or LMD (OR 5.91 [2.19, 15.99]). The modification of the association between divorce and severe CAD by gender was statistically significant for severe LMD (Pinteraction 0.0008) and marginally significant for CAD (Pinteraction 0.05). Among women, there was a significant adjusted association between number of divorces and severe CAD (OR 2.4 [95% CI 1.2, 4.5]), MVD (OR 2.0 [95% CI 1.4, 3.0]), and LMD (OR 3.4 [95% CI 1.9, 5.9]). In conclusion, divorce, particularly multiple divorces, is associated with severe CAD, MVD, and LMD in women but not in men

The link between shrimp farm runoff and blooms of toxic Heterosigma akashiwo in Red Sea coastal waters

In May 2010 a copious bloom of the raphidophyte Heterosigma akashiwo was observed for the first time in Red Sea waters off the coasts of Saudi Arabia. This bloom was confined to an area where water and phytoplankton flow freely between the sea and a shrimp farm. The phytoplankton density and physico-chemical characteristics of the sea water were therefore investigated weekly at bloom and non-bloom sites in order to gain insight into the environmental factors prevailing at the bloom site and their link with the shrimp farm runoff. The bloom site showed higher nutrient concentrations than the non-bloom site, indicating the possible role of the shrimp farm in flushing nutrients into this site. The bloom appeared on 27 May, coinciding with a decrease in salinity (19◦C). The results of toxicological assays showed that both bloom samples and batch cultures of H. akashiwo were toxic to Artemia salina and exhibited haemolytic activity with respect to rabbit erythrocytes. Bloom samples showed a higher toxicity (LC50 = 8.9 × 104 cells ml−1) and haemolytic activity (EC50 = 3.64 × 104 cells ml−1) than the batch cultures (LC50 =11.6×104 cells ml−1, EC50 =5.1×104 cells ml−1). In the light of the results of this study, the link between H. akashiwo blooms and shrimp farm runoff should be considered during the monitoring of Red Sea coastal waters for the presence of harmful algal blooms

Questionable child deaths in Riyadh, Saudi Arabia: Retrospective Study

Abstract Background Despite the efforts of the governmental child protection programs, child fatalities due to maltreatment remain a serious problem in Arab countries. Results This retrospective study identified 87 as a total questionable child death (QCD) cases in Riyadh, the capital of Kingdome of Saudi Arabia. 52 victims (60%) were Saudi children. Nearly one-third (29%) of the cases involved the death of children ages 1–5. 21 QCDs occurred in middle and the eastern regions of the country. QCDs were most commonly reported as accidental (29%), followed by homicidal (25%). A parent was the main assailant in (38%) of the homicidal cases, and the child’s relative was reported in (18%). Wounds were detected as the cause of death in 39 cases (45%). Upon examination, child negligence was reported or observed in 5 cases. Conclusion This study provides appropriate data for planning preventive measures