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Papers by Paul Erasto

Research paper thumbnail of Antimicrobial and cytotoxic activities of fresh leaf extracts of Warburgia ugandensis

Tanzania Journal of …, 2009

Warburga ugandenss Sprague (Canellaceae), is widely used by Traditional Health Practitioners in E... more Warburga ugandenss Sprague (Canellaceae), is widely used by Traditional Health Practitioners in Eastern and Southern Africa for treatment of diseases and conditions associated with HIV/AIDS infections. The most commonly prescribed parts of the plant are usually barks and roots. The aim of this study was to investigate whether leaves of this plant have biological activities comparable to those of barks and roots. Fresh leaves of W. ugandenss were freeze-dried to complete dryness while another portion of the leaves from the same collection were air-dried under shade. Ethanolic extracts from the two differently dried leaves were tested for antimicrobial activity and for brine shrimp toxicity test. Ethanolic extract from the freeze-dried leaves exhibited both antibacterial activity against standard strains of Staphylococcus aureus, Eschercha col, Vbro cholerae, Bacllus cereus and antifungal activity against Candda albcans and Cryptococcus neoformans. The extract from the air-dried leaves showed similar antibacterial activity against the mentioned organisms but had no antifungal activity. However, both extracts exhibited comparable cytotoxic activity (95% CI), against brine shrimp larvae with reference to cyclophosphamide, a standard anticancer drug. Fresh leaves of W. ugandenss have shown to exhibit anticandida activity, a factor which substantiates their application as a traditional herbal remedy to complement treatment of fungal infections in HIV/AIDS patients. Further studies to establish constituents responsible for the exhibited antifungal activity are highly desirable.

Research paper thumbnail of Digital Image Watermarking Using DWT to Secure Digital Content Ownership

Thesis Chapters by Paul Erasto

Research paper thumbnail of Digital Image Watermarking Using DWT to Secure Digital Content Ownership

Digital Image Watermarking Using DWT to Secure Digital Content Ownership, 2010

In this new era of technology, information and communication technology is getting advanced compa... more In this new era of technology, information and communication technology is getting advanced compared to the past decades. The emergence of Internet and networking bring a lot of benefits to mankind nowadays. Technology is getting improved after a lot of research has been done. We can see the evolution of our world, from an agricultural society to an industrial society. Different kind of digital products are being invented during this evolution. Digital images, MP3s, videos are widely used everywhere in this world. The evolution of image capture tool has evolved from
film camera to digital camera. Film capture is no longer used nowadays. Digital camera is commonly used to capture pictures. Captured images are converted into pixels form and saved into digital signal form. Users can upload their images into computer or onto internet. However, images uploaded are widely spread and copied by other internet users. This may cause a serious copyright problem because the original owner of the image cannot prove that the image belongs to the owner. A digital right management technique by using watermarking system is introduced in the report to prevent this problem. DWT watermarking system is a system which will embed certain information into digital image by using DWT decomposition. Owner can use the extraction method to show the ownership of images if his/her images are copied or stolen by other people. This watermarking system contains two major process, which is embedding process and extraction process. The watermark used will be an image with meaningful text inside.

Research paper thumbnail of Antimicrobial and cytotoxic activities of fresh leaf extracts of Warburgia ugandensis

Tanzania Journal of …, 2009

Warburga ugandenss Sprague (Canellaceae), is widely used by Traditional Health Practitioners in E... more Warburga ugandenss Sprague (Canellaceae), is widely used by Traditional Health Practitioners in Eastern and Southern Africa for treatment of diseases and conditions associated with HIV/AIDS infections. The most commonly prescribed parts of the plant are usually barks and roots. The aim of this study was to investigate whether leaves of this plant have biological activities comparable to those of barks and roots. Fresh leaves of W. ugandenss were freeze-dried to complete dryness while another portion of the leaves from the same collection were air-dried under shade. Ethanolic extracts from the two differently dried leaves were tested for antimicrobial activity and for brine shrimp toxicity test. Ethanolic extract from the freeze-dried leaves exhibited both antibacterial activity against standard strains of Staphylococcus aureus, Eschercha col, Vbro cholerae, Bacllus cereus and antifungal activity against Candda albcans and Cryptococcus neoformans. The extract from the air-dried leaves showed similar antibacterial activity against the mentioned organisms but had no antifungal activity. However, both extracts exhibited comparable cytotoxic activity (95% CI), against brine shrimp larvae with reference to cyclophosphamide, a standard anticancer drug. Fresh leaves of W. ugandenss have shown to exhibit anticandida activity, a factor which substantiates their application as a traditional herbal remedy to complement treatment of fungal infections in HIV/AIDS patients. Further studies to establish constituents responsible for the exhibited antifungal activity are highly desirable.

Research paper thumbnail of Digital Image Watermarking Using DWT to Secure Digital Content Ownership

Research paper thumbnail of Digital Image Watermarking Using DWT to Secure Digital Content Ownership

Digital Image Watermarking Using DWT to Secure Digital Content Ownership, 2010

In this new era of technology, information and communication technology is getting advanced compa... more In this new era of technology, information and communication technology is getting advanced compared to the past decades. The emergence of Internet and networking bring a lot of benefits to mankind nowadays. Technology is getting improved after a lot of research has been done. We can see the evolution of our world, from an agricultural society to an industrial society. Different kind of digital products are being invented during this evolution. Digital images, MP3s, videos are widely used everywhere in this world. The evolution of image capture tool has evolved from
film camera to digital camera. Film capture is no longer used nowadays. Digital camera is commonly used to capture pictures. Captured images are converted into pixels form and saved into digital signal form. Users can upload their images into computer or onto internet. However, images uploaded are widely spread and copied by other internet users. This may cause a serious copyright problem because the original owner of the image cannot prove that the image belongs to the owner. A digital right management technique by using watermarking system is introduced in the report to prevent this problem. DWT watermarking system is a system which will embed certain information into digital image by using DWT decomposition. Owner can use the extraction method to show the ownership of images if his/her images are copied or stolen by other people. This watermarking system contains two major process, which is embedding process and extraction process. The watermark used will be an image with meaningful text inside.