Nephrocalcinosis and its outcome has been widely studied in the preterm population. There is a pa... more Nephrocalcinosis and its outcome has been widely studied in the preterm population. There is a paucity of data regarding nephrocalcinosis in term babies. Prospective case series, in which ten neonates were included in the study from November 2013 and April 2014. All neonates with nephrocalcinosis diagnosed by ultrasound of kidney, ureters, bladder (KUB) done antenatally or during evaluation for urinary tract infection in neonates with hyperbilirubinemia/sepsis were included. All preterm neonates and neonates with congenital urinary tract anamolies were excluded from this case series. Cases were followed to know the outcome of the condition by follow-up ultrasonography. Follow-up ultrasound kidneys after 2-4 weeks revealed no evidence of nephrocalcinosis in majority of the cases. In one case, hypocitrateuria was documented. Hence, nephrocalcinosis is a transient phenomenon but needs close monitoring with follow-up scans. In this case series we investigated nephrocalcinosis with early...
III-Nitride based deep ultraviolet (UV) light emitting diodes (LEDs) emitting below 280nm has the... more III-Nitride based deep ultraviolet (UV) light emitting diodes (LEDs) emitting below 280nm has the potential to replace mercury lamps currently used in the systems for water/air purification, germicidal and medical instruments sterilization applications. However, this potential has not yet been fully realized as the output power, quantum efficiency and lifetime of deep UV-LEDs have been limited by the large number of dislocations in the active region of the devices, arising from the lattice mismatched sapphire substrate, which has been the substrate of choice due to its high transparency to deep UV radiation. To reduce dislocations in the active region of the DUV LEDs grown on sapphire, AlN/AlGaN short period superlattice is usually grown to manage strain and filter the dislocations. However, the growth of these thick superlattice is not only time consuming but it can also cause severe substrate bowing making device fabrication a challenge. An alternative method for reducing the disl...
ABSTRACT 285 nm stimulated emission (SE) is demonstrated at room temperature from optically-pumpe... more ABSTRACT 285 nm stimulated emission (SE) is demonstrated at room temperature from optically-pumped AlGaN multiple quantum wells (MQWs) deposited between a Si-doped AlGaN current spreading layer and a 25 nm Mg-doped p-type AlGaN clad layer. The epitaxial structures were grown by low pressure metalorganic chemical vapor deposition (MOCVD) on high-quality AlN/sapphire templates and a pulsed ArF excimer laser was used as the excitation source for lasing experiments. The threshold power density (Pth) was measured to be 970 kW/cm2 and the SE was strongly polarized in transverse electric (TE) mode. The minimum emission linewidth was ~2 nm. The high value of Pth is primarily attributed to optical losses due to pump laser absorption in the top p-AlGaN. Our results show the viability of the MOCVD growth technology in conjunction with c-plane sapphire substrates to develop electrically-pumped deep-UV laser diodes.
Abstract: Deep ultraviolet (DUV) light emitting diodes (LEDs) based on group III-Nitrides have nu... more Abstract: Deep ultraviolet (DUV) light emitting diodes (LEDs) based on group III-Nitrides have numerous potential applications in water and air purification, food sterilization, ultraviolet curing, chemical and biological sensors, and medical instrumentation. However ...
Nephrocalcinosis and its outcome has been widely studied in the preterm population. There is a pa... more Nephrocalcinosis and its outcome has been widely studied in the preterm population. There is a paucity of data regarding nephrocalcinosis in term babies. Prospective case series, in which ten neonates were included in the study from November 2013 and April 2014. All neonates with nephrocalcinosis diagnosed by ultrasound of kidney, ureters, bladder (KUB) done antenatally or during evaluation for urinary tract infection in neonates with hyperbilirubinemia/sepsis were included. All preterm neonates and neonates with congenital urinary tract anamolies were excluded from this case series. Cases were followed to know the outcome of the condition by follow-up ultrasonography. Follow-up ultrasound kidneys after 2-4 weeks revealed no evidence of nephrocalcinosis in majority of the cases. In one case, hypocitrateuria was documented. Hence, nephrocalcinosis is a transient phenomenon but needs close monitoring with follow-up scans. In this case series we investigated nephrocalcinosis with early...
III-Nitride based deep ultraviolet (UV) light emitting diodes (LEDs) emitting below 280nm has the... more III-Nitride based deep ultraviolet (UV) light emitting diodes (LEDs) emitting below 280nm has the potential to replace mercury lamps currently used in the systems for water/air purification, germicidal and medical instruments sterilization applications. However, this potential has not yet been fully realized as the output power, quantum efficiency and lifetime of deep UV-LEDs have been limited by the large number of dislocations in the active region of the devices, arising from the lattice mismatched sapphire substrate, which has been the substrate of choice due to its high transparency to deep UV radiation. To reduce dislocations in the active region of the DUV LEDs grown on sapphire, AlN/AlGaN short period superlattice is usually grown to manage strain and filter the dislocations. However, the growth of these thick superlattice is not only time consuming but it can also cause severe substrate bowing making device fabrication a challenge. An alternative method for reducing the disl...
ABSTRACT 285 nm stimulated emission (SE) is demonstrated at room temperature from optically-pumpe... more ABSTRACT 285 nm stimulated emission (SE) is demonstrated at room temperature from optically-pumped AlGaN multiple quantum wells (MQWs) deposited between a Si-doped AlGaN current spreading layer and a 25 nm Mg-doped p-type AlGaN clad layer. The epitaxial structures were grown by low pressure metalorganic chemical vapor deposition (MOCVD) on high-quality AlN/sapphire templates and a pulsed ArF excimer laser was used as the excitation source for lasing experiments. The threshold power density (Pth) was measured to be 970 kW/cm2 and the SE was strongly polarized in transverse electric (TE) mode. The minimum emission linewidth was ~2 nm. The high value of Pth is primarily attributed to optical losses due to pump laser absorption in the top p-AlGaN. Our results show the viability of the MOCVD growth technology in conjunction with c-plane sapphire substrates to develop electrically-pumped deep-UV laser diodes.
Abstract: Deep ultraviolet (DUV) light emitting diodes (LEDs) based on group III-Nitrides have nu... more Abstract: Deep ultraviolet (DUV) light emitting diodes (LEDs) based on group III-Nitrides have numerous potential applications in water and air purification, food sterilization, ultraviolet curing, chemical and biological sensors, and medical instrumentation. However ...
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Papers by Fatima Asif