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Ultraviolet light

About: Ultraviolet light is a research topic. Over the lifetime, 49494 publications have been published within this topic receiving 843151 citations.


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Patent
06 Jul 1995
TL;DR: In this paper, the output of a continuously pumped, Q-switched, Nd:YAG laser (10) is frequency converted to provide ultraviolet light for forming vias (72, 74) in multi-layered targets (40).
Abstract: The output of a continuously pumped, Q-switched, Nd:YAG laser (10) is frequency converted to provide ultraviolet light (62) for forming vias (72, 74) in multi-layered targets (40). The parameters of the output pulses (62) are selected to facilitate substantially clean, simultaneous or sequential drilling or via formation in a wide variety of materials such as metals, organic dielectrics, and reinforcement materials having different thermal absorption characteristics in response to ultraviolet light. These parameters typically include at least two of the following criteria: high average power of greater than about 100 milliwatts measured over the beam spot area, a temporal pulse width shorter than about 100 nanoseconds, a spot diameter of less than about 50 microns, and a repetition rate of greater than about one kilohertz. The laser system (10) and method circumvent conventional depth of cut saturation limitations and can achieve an increased depth of cut per pulse in a target (40) formed of either single- or multi-layered material.

258 citations

Journal ArticleDOI
TL;DR: Genetic and sequencing studies of ultraviolet light (u.v.)-induced mutations in the lacI gene of Escherichia coli show the following: u.v. stimulates many types of mutations, and both transitions and transversions occur, although the most favored mutational sites involve G X C----A X T transitions.

258 citations

Journal ArticleDOI
18 Jan 2002-Langmuir
TL;DR: In this article, a new scheme for attachment of functionalized organic molecules to polycrystalline diamond films was proposed, where ultraviolet light was used to cause a local reaction between a hydrogen-terminated diamond surface and organic molecules present as a thin overlayer liquid film.
Abstract: We report a new scheme for attachment of functionalized organic molecules to polycrystalline diamond films. In this scheme, ultraviolet light is used to cause a local reaction between a hydrogen-terminated diamond surface and organic molecules present as a thin overlayer liquid film. Comparison of functionalized alkenes and alkanes shows that alkenes attach more efficiently. By attaching organic molecules with suitable protecting groups and then deprotecting after attachment to the surface, it is possible to prepare diamond surfaces terminated with carboxylic acid groups or with primary amine groups. These functional groups may serve as an attractive starting point for further chemical modification of diamond surfaces.

257 citations

Journal ArticleDOI
TL;DR: It is shown for the first time that far-UVC efficiently inactivates airborne aerosolized viruses, with a very low dose of 2 mJ/cm2 of 222-nm light inactivating >95% of aerosolization H1N1 influenza virus.
Abstract: Airborne-mediated microbial diseases such as influenza and tuberculosis represent major public health challenges. A direct approach to prevent airborne transmission is inactivation of airborne pathogens, and the airborne antimicrobial potential of UVC ultraviolet light has long been established; however, its widespread use in public settings is limited because conventional UVC light sources are both carcinogenic and cataractogenic. By contrast, we have previously shown that far-UVC light (207–222 nm) efficiently inactivates bacteria without harm to exposed mammalian skin. This is because, due to its strong absorbance in biological materials, far-UVC light cannot penetrate even the outer (non living) layers of human skin or eye; however, because bacteria and viruses are of micrometer or smaller dimensions, far-UVC can penetrate and inactivate them. We show for the first time that far-UVC efficiently inactivates airborne aerosolized viruses, with a very low dose of 2 mJ/cm2 of 222-nm light inactivating >95% of aerosolized H1N1 influenza virus. Continuous very low dose-rate far-UVC light in indoor public locations is a promising, safe and inexpensive tool to reduce the spread of airborne-mediated microbial diseases.

256 citations

Journal ArticleDOI
TL;DR: The survival deficit is increasing with longer follow-up of the survivors, and is worse in males, and the majority of cases of cancer occurring before age 30 appear to be spontaneous and unrelated to either carcinogens in the environment or family cancer syndromes.
Abstract: Incidence Cancer occurring between the ages of 15 and 30 years is 2.7 times more common than cancer occurring during the first 15 years of life, yet is much less common than cancer in older age groups, and accounts for just 2% of all invasive cancer. Cancer in adolescents and young adults is unique in the distribution of the types that occur. Hodgkin lymphoma, melanoma, testis cancer, female genital tract malignancies, thyroid cancer, soft-tissue sarcomas, non-Hodgkin lymphoma, leukemia, brain and spinal cord tumors, breast cancer, bone sarcomas, and nongonadal germ cell tumors account for 95% of the cancers in this age group. The frequency distribution of cancer types changes dramatically from age 15-30, such that the pattern at the youngest age does not resemble the one at the oldest. The incidence of cancer in this age group increased steadily during the past quarter century. This increase is declining and at the older end of the age range appears to be returning to the incidence of the 1970s. Males in the 15- to 29-year age group have been at higher risk of developing cancer, with the risk directly proportional to age. Non-Hispanic whites have had the highest risk of developing cancer during this phase of life, and Asians, American Indians and Native Alaskans the lowest. Males had a worse prognosis than females. African-Americans, American Indian/Alaska Natives had a worse prognosis than white non-Hispanics and Asians. MORTALITY & SURVIVAL: At the beginning of the last quarter century, the diagnosis of cancer in 15- to 29-year-olds carried a more favorable prognosis, on the average, relative to cancer at other ages. Since then, there has been a lack of progress in survival improvement among older adolescents and young adults relative to all other ages. Survival improvement trends portend a worse prognosis for young adults diagnosed with cancer today than 25 years ago. The survival deficit is increasing with longer follow-up of the survivors, and is worse in males. Among 15- to 29-year-olds, non-Hispanic whites had the best survival and African Americans/blacks had the worst survival, with a 20% difference apparent by 5 years. Asians/Pacific Islanders had the second best survival, with Hispanics and American Indians/Alaska Natives next in sequence. Risk factors In general, there are relatively scant data to support either an environmental causation or an inherited predisposition to cancer in this age group. The majority of cases of cancer occurring before age 30 appear to be spontaneous and unrelated to either carcinogens in the environment or family cancer syndromes. Overall, family cancer syndromes appear to account for less than 5% of the cases of cancer in the age group. Melanoma, cervical carcinoma and Kaposi sarcoma, non-Hodgkin lymphoma, Hodgkin and Burkitt lymphomas accounting for the majority of environmentally induced malignancies (ultraviolet light, human papillomavirus, human immunodeficiency virus, and Epstein-Barr virus, respectively). Ultimately, a larger proportion of cases may be attributable to specific factors or genetic predisposition, but at present, most cancer in this age group appears to be sporadic and random.

256 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202346
2022181
20211,101
20201,978
20192,639
20182,772