A Preliminary Study for Ant Colony Optimization with a new Reinforcement Strategy

Different Ants Colony Optimization (ACO) algorithms use pheromone information differently in an attempt to improve their relative performance. In this paper, we describe a new systematic reinforcement strategy as a means to improve the pheromone update rules of existing ACO algorithms. We examine the proposed strategy and compare it with other improvement strategies using the well - known Traveling Salesman Problem (TSP). The results indicate that the performance of both the AntSystem (AS) and the Ant Colony System (ACS) algorithms is improved by applying the proposed strategy. We postulate that the proposed strategy allows the ants, in some sense, to both refine the search in promising regions, and escape explored areas of the search space more consistently and effectively than other reinforcement strategies

Clinical Presentation and Time-Based Mortality in Patients With Chest Injuries Associated With Road Traffic Accidents

Background: Blunt chest trauma (BCT) poses significant morbidity and mortality worldwide. Objectives: We investigated the clinical presentation and outcome of BCT related to road traffic accidents (RTA). Patients and Methods: A retrospective observational analysis for patients who sustained BCT secondary to RTA in terms of motor vehicle crash (MVC) and pedestrian-motor vehicle accidents (PMVA) who were admitted to the trauma center at Hamad general hospital, Doha, Qatar, between 2008 and 2011. Results: Of 5118 traumatic injury cases, 1004 (20%) were found to have BCT secondary to RTA (77% MVC and 23% PMVA). The majority were males (92%), and expatriates (72%). Among MVCs, 84% reported they did not use protective devices. There was a correlation between chest abbreviated injury score (AIS) and injury severity scoring (ISS) (r = 0.35, r2 = 0.12, P < 0.001). Regardless of mechanism of injury (MOI), multivariate analysis showed that the head injury associated with chest AIS and ISS was a predictor of mortality in BCT. Overall mortality was 15%, and the highest rate was observed within the first 24 hours post-trauma. Conclusions: Blunt chest trauma from RTA represents one-fifth of the total trauma admissions in Qatar, with a high overall mortality. Pedestrians are likely to have more severe injuries and higher fatality rates than MVC victims. Specific injury prevention programs focusing on road safety should be implemented to minimize the incidence of such preventable injuries

Oral carriage of candidiasis in patients with oral dental diseases : predisposing factors, species and their antifungal susceptibility patterns

The aim of this study was to evaluate prevalence, frequency and predisposing factors as well as their antifungal susceptibility pattern of oral candidiasis (OC) in patients attending outpatient\u2019s dental clinic with various dental diseases. A total of 150 patients were enrolled in this study aged from 4 to 73 years attended outpatient dental clinic, at Zahra district Tripoli, Libya between May 20017 and May 2018. The purpose of this study was to evaluate the frequency of yeasts in the oral cavity, and to determine the main yeast species present, their correlation with various dental problems as well as other predisposing factors and there antifungal susceptibility patterns. One hundred and fifty patients were enrolled in this study. Patients were submitted to an odontological examination for the identification of dental caries and dental plaque, and other dental problems, as well as for yeast culture. Identification of all species was based on standard mycological methods and antifungal susceptibility test was performed by using disk diffusion susceptibility method and several antifungal drugs such as (fluconazole, amphotericin B, ketoconazole, econazole, itraconazole) were used. The frequency oral carriage of yeasts was 64 % (96), with 78% aged from 20 to 60 years old. Caries, plaque, gingivitis periodontitis, and lower teeth are the most dental problem in which, more than 50% harbors candida species in their oral cavity. Diabetes, pregnancy and smoking, is among common predisposing factors. Candida albicans was the most prevalent species (41.7%), C. glabrate (27.1%) and C. dubliniensis (11.5%). Susceptibility test show that Candida albicans was highly resistant to most azole antifungal and Candida dubliniensis was highly resistant to fluocytosine. Other candida species show variable susceptibility to various antifungal drugs. Aim of study: The purpose of this study was to evaluate the frequency of yeasts in the oral cavity, and to determine the main yeast species present, their correlation with various dental problems as well as other predisposing factors and there antifungal susceptibility patterns. One hundred and fifty patients were enrolled in this study. Patients were submitted to an odontological examination for the identification of dental caries and dental plaque, and other dental problems, as well as for yeast culture. Identification of all species was based on standard mycological methods and antifungal susceptibility test was performed by using disk diffusion susceptibility method and several antifungal drugs such as (fluconazole, amphotericin B, ketoconazole, econazole, itraconazole) were used. Material and methods: One hundred and fifty patients were enrolled in this study. Patients were submitted to an odontological examination for the identification of dental caries and dental plaque, and other dental problems, as well as for yeast culture. Identification of all species was based on standard mycological methods and antifungal susceptibility test was performed by using disk diffusion susceptibility method and several antifungal drugs such as (fluconazole, amphotericin B, ketoconazole, econazole, itraconazole) were used. Results: The frequency oral carriage of yeasts was 64 % (96), with 78% aged from 20 to 60 years old. Caries, plaque, gingivitis periodontitis, and lower teeth are the most dental problem in which, more than 50% harbors candida species in their oral cavity. Diabetes, pregnancy and smoking, is among common predisposing factors. Candida albicans was the most prevalent species (41.7%), C. glabrate (27.1%) and C. dubliniensis (11.5%). Susceptibility test show that Candida albicans was highly resistant to most azole antifungal and Candida dubliniensis was highly resistant to fluocytosine. Other candida species show variable susceptibility to various antifungal drugs. Conclusion: This finding indicated a correlation between the presence of caries and other dental diseases with yeasts carriage in the mouth. However, there was no clear cut correlation between yeasts carriage in healthy and health patients

Molecular-Type Specific Multiplex PCR produces a distinct VNII PCR pattern among Cryptococcus neoformans species complex

Prevalence of molecular type VNII among Cryptococcus neoformans species complex is probably underestimated since it can be distinguished from VNI only using molecular typing methods such as URA5-RFLP, AFLP, MLST, or whole genome sequencing. Previously, we described a multiplex polymerase chain reaction (PCR) method able to identify VNI, VNIV, and VNIII hybrids, but, at that time, VNII molecular type was not described yet. In this study, 16 VNII global isolates were analyzed by our multiplex PCR method, and results showed that it was able to produce a specific pattern for all the studied VNII isolates, which was different from those of VNI, VNIV, and VNIII

Yeasts of the genus Candida are the dominant cause of onychomycosis in Libyan women but not men: results of a 2-year surveillance study

BACKGROUND: The reported frequency of recovery of fungi from infected nails varies according to the geographical area. OBJECTIVES: To establish the nature of the causal agents in a sample of the Libyan population presenting with suspected onychomycosis. METHODS: Samples were taken from the infected fingernails of 648 patients attending the Tripoli Medical Centre. RESULTS: Samples from 500 patients proved positive for fungi following culturing, while 476 were potassium hydroxide and culture positive. Of the culture-positive samples, yeasts of the genus Candida (C. albicans, C. parapsilosis, C. glabrata, C. guillermondii and C. tropicalis) were the dominant cause of this condition in women (417 of 434, 96%) but were responsible for only a minority of cases in men (three of 66, 5%). In contrast, dermatophytes (Trichophyton violaceum, T. rubrum, T. mentagrophytes and Microsporum canis) were responsible for this condition in the majority of cases in men (53 of 66, 80%) but only 3% (15 of 434) of cases in women. The mould Aspergillus nidulans was isolated from the nails of 10 (15%) men and two (0.5%) women. CONCLUSIONS: The data obtained in this study reveal an almost total separation of the aetiological agents responsible for onychomycosis based on gender

First report of two cases of cryptococcosis in Tripoli, Libya, infected with Cryptococcus neoformans isolates present in the urban area

Cryptococcosis is a potentially fatal fungal disease caused by the basidiomycetes yeasts Cryptococcus neoformans and C. gattii with high predilection to invade the central nervous system mainly in immunocompromised hosts. Skin can be secondarily involved in disseminated infection or be exceptionally involved as primary cutaneous infection by inoculation with contaminated materials. We report the first two Libyan cases of cryptococcal meningitis in HIV patients, in which one of them presented a secondary cutaneous involvement due to systemic dissemination. The first patient was a 17-year-old female, had fever, cough, headache and intractable vomiting as well as itchy water bumps on her skin and upper limbs. The cutaneous eruption prompted the accurate diagnosis. Cultures were positive for C. neoformans in both cerebrospinal fluid and skin specimens, as well as cryptococcal antigen was detected in serum. The isolate was identified, by molecular analysis, as C. neoformans AD-hybrid belonging to molecular type VNIII and mating type \u3b1AA\u3b1, the same genotype found for some environmental isolates recovered from olive trees in Tripoli. The second patient was a 36-years-old male with a long history of HIV on irregular treatment. Cryptococcal antigen in serum was positive and cultures yielded the growth of C. neoformans var. grubii, molecular type VNI and mating type \u3b1A. Both patients did not respond adequately to treatment and died of impaired central nervous system function and respiratory failure, respectively

Oral Candida colonization in HIV-infected patients: Species and antifungal susceptibility in Tripoli/Libya

Introduction: Candidiasis is more frequent in human immunodeficiency virus (HIV)-infected patients and knowledge about the distribution and antifungal susceptibility of oral Candida species is important for effective management of candidiasis. Material and Methods: An oral rinses sample collected from hundred HIV-infected patients with and without clinical evidence of oral candidiasis in this study at the Infectious Department/Tripoli Medical Center, Libya. Species identified by standard phenotypic and conventional methods and in vitro susceptibility testing of the yeast isolates to antifungals were performed using the Disc diffusion method protocol as recommended by the Clinical Laboratory Scientific Institute. Results: Oral Candida colonization is detected in all patients with and without clinical syndromes, and Candida albicans were accounted for (74%), C. dubliniensis (11%) and C. glabrata (6%). A high proportion of Candida species (42%) showed decreased susceptibility to fluconazole. Among C., albicans more than 30% of isolate were resistant to most new azole antifungal including fluconazole, itraconazole, posoconazole and voriconazole. Conclusions: A significant number of oral Candida species particular Candida albicans exhibiting decreased susceptibility to fluconazole were isolated from colonized HIV-infected individual, given the high incidence and severity of fungal infections in HIV-infected individuals. The results of this study reinforce the importance of antifungal susceptibility testing, which contributes to the therapeutic strategies and highlights the need for continuous surveillance of Candida colonization in this population