Secondary Organic Aerosol Formation from Healthy and Aphid-Stressed Scots Pine Emissions.

One barrier to predicting biogenic secondary organic aerosol (SOA) formation in a changing climate can be attributed to the complex nature of plant volatile emissions. Plant volatile emissions are dynamic over space and time, and change in response to environmental stressors. This study investigated SOA production from emissions of healthy and aphid-stressed Scots pine saplings via dark ozonolysis and photooxidation chemistry. Laboratory experiments using a batch reaction chamber were used to investigate SOA production from different plant volatile mixtures. The volatile mixture from healthy plants included monoterpenes, aromatics, and a small amount of sesquiterpenes. The biggest change in the volatile mixture for aphid-stressed plants was a large increase (from 1.4 to 7.9 ppb) in sesquiterpenes-particularly acyclic sesquiterpenes, such as the farnesene isomers. Acyclic sesquiterpenes had different effects on SOA production depending on the chemical mechanism. Farnesenes suppressed SOA formation from ozonolysis with a 9.7-14.6% SOA mass yield from healthy plant emissions and a 6.9-10.4% SOA mass yield from aphid-stressed plant emissions. Ozonolysis of volatile mixtures containing more farnesenes promoted fragmentation reactions, which produced higher volatility oxidation products. In contrast, plant volatile mixtures containing more farnesenes did not appreciably change SOA production from photooxidation. SOA mass yields ranged from 10.8 to 23.2% from healthy plant emissions and 17.8-26.8% for aphid-stressed plant emissions. This study highlights the potential importance of acyclic terpene chemistry in a future climate regime with an increased presence of plant stress volatiles

Human Tissue Plasminogen Activator Expression in Escherichia coli using Cytoplasmic and Periplasmic Cumulative Power

Abstract Tissue plasminogen activator (tPA) is a serine protease, which is composed of five distinct structural domains with 17 disulfide bonds, representing a model of high-disulfide proteins in human body. One of the most important limitations for high yield heterologous protein production in Escherichia coli (E. coli) is the expression of complex proteins with multiple disulfide bridges. In this study the combination of two distinct strategies, manipulated cytoplasm and native periplasm, was applied to produce the functional full length tPA enzyme in E. coli. Using a PelB signal peptide sequence at 5' site of tPA gene, the expression cassette was prepared and subsequently was transformed into a strain with manipulated oxidizing cytoplasm. Then the induction was made to express the protein of interest. The SDS-PAGE analysis and gelatin hydrolysis confirmed the successful expression of functional tPA. The results of this study showed that complex proteins can be produced in E. coli using the cumulative power of both cytoplasm and periplasm

Aerosol chemistry of riparian shrub emissions and oxygenated terpenes

Biogenic volatile organic compounds (BVOCs) released primarily from vegetation are themajor contributors to the total atmospheric volatile organic compounds (VOCs) globally. These BVOCs can play important ecological functions. In Chapter 1, I summarized the ecological roles of these important atmospheric volatiles at the organism and population, and community levels, their adaptive values, and their impacts at the climate level. In addition to the ecological processes, plant VOCs can influence atmospheric chemistry and physics. Many of these plant VOCs are highly reactive, and upon release into the atmosphere, they react with atmospheric radicals forming secondary organic aerosol (SOA). SOA can affect human health and impact Earth’s radiative balance directly and indirectly by absorbing and scattering sunlight and influencing clouds' formation and properties, respectively. I investigated SOA formation from less-studied VOCs in the laboratory by generating SOA inside an oxidation flow reactor (OFR) using different VOCs as SOA precursors. In Chapter 2, I investigated SOA formation from a riparian shrub emission exposed to insect herbivory. The acyclic BOVCs, regardless of herbivory stress, reduced SOA potential formation. This result can have an important implication for SOA prediction in chemical transport models. In Chapter 3, I studied SOA from dominant BVOCs of a shrub species in California’s coastal sage shrub ecosystem. SOA formation potential of most of these oxygenated monoterpenes was higher than that of a common plant volatile, α-pinene, as a reference system. I also investigated the chemical composition of the SOA from these oxygenated terpenes and compared that with the SOA chemical composition formed from real plant emissions that were dominated by these compounds. I observed that the chemical composition of SOA from plant mixtures was similar to each other and equally different from SOA formed from single precursors. This result emphasized that SOA formed from single VOC standards does not capture the complexity of VOC emissions from real plants

The Effect of Topical Nifedipine in Treatment of Chronic Anal Fissure

Chronic anal fissure is the most common cause of anal pain associated with internal anal sphincter hypertonia. Reduction of hypertonocity is a special treatment for fissure healing. For this purpose chronic anal fissures were conventionally treated by anal dilatation or by lateral sphincterotomy. However, both of these methods may cause a degree of incontinence in some patients. The uptake of medical therapies that create a reversible chemical sphincterotomy has recently become widespread. The aim of this prospective clinical trial study was to assess the effectiveness of nifedipine in healing anal fissure, a calcium channel blocker that reduces sphincter pressure. A single-blind randomized comparative trial was setup to compare traditional treatment with stool softeners and 2% lidocaine cream against 0.5% nifedipine cream for 4 weeks. 110 patients were included in this study, 60 patients in the nifedipine group and 50 patients in the control group and the therapeutic outcome and side effects were recorded. Healing had occurred in 70% of patients in the nifedipine group and in 12% of patients in the control group after 4 weeks treatment (P < 0.005). Recurrence of symptoms occurred in four of healed patients in the nifedipine group and three patients in the control group in two months. The final result of nifedipine application after 12 months follow up was recurrence in 11 patients (26.19%). Mild headache occurred in four patients (6.6%) of the nifedipine group. Patients in the nifedipine group showed significant healing and relief from pain compared with patients in the control group. Recurrence rate with nifedipine use in spite of control of predisposing factors such as constipation was significant. Another finding was low complication rate with this treatment

Secondary Organic Aerosol Formation from Healthy and Aphid-Stressed Scots Pine Emissions.

One barrier to predicting biogenic secondary organic aerosol (SOA) formation in a changing climate can be attributed to the complex nature of plant volatile emissions. Plant volatile emissions are dynamic over space and time, and change in response to environmental stressors. This study investigated SOA production from emissions of healthy and aphid-stressed Scots pine saplings via dark ozonolysis and photooxidation chemistry. Laboratory experiments using a batch reaction chamber were used to investigate SOA production from different plant volatile mixtures. The volatile mixture from healthy plants included monoterpenes, aromatics, and a small amount of sesquiterpenes. The biggest change in the volatile mixture for aphid-stressed plants was a large increase (from 1.4 to 7.9 ppb) in sesquiterpenes-particularly acyclic sesquiterpenes, such as the farnesene isomers. Acyclic sesquiterpenes had different effects on SOA production depending on the chemical mechanism. Farnesenes suppressed SOA formation from ozonolysis with a 9.7-14.6% SOA mass yield from healthy plant emissions and a 6.9-10.4% SOA mass yield from aphid-stressed plant emissions. Ozonolysis of volatile mixtures containing more farnesenes promoted fragmentation reactions, which produced higher volatility oxidation products. In contrast, plant volatile mixtures containing more farnesenes did not appreciably change SOA production from photooxidation. SOA mass yields ranged from 10.8 to 23.2% from healthy plant emissions and 17.8-26.8% for aphid-stressed plant emissions. This study highlights the potential importance of acyclic terpene chemistry in a future climate regime with an increased presence of plant stress volatiles

Secondary Organic Aerosol Formation from Healthy and Aphid-Stressed Scots Pine Emissions.

One barrier to predicting biogenic secondary organic aerosol (SOA) formation in a changing climate can be attributed to the complex nature of plant volatile emissions. Plant volatile emissions are dynamic over space and time, and change in response to environmental stressors. This study investigated SOA production from emissions of healthy and aphid-stressed Scots pine saplings via dark ozonolysis and photooxidation chemistry. Laboratory experiments using a batch reaction chamber were used to investigate SOA production from different plant volatile mixtures. The volatile mixture from healthy plants included monoterpenes, aromatics, and a small amount of sesquiterpenes. The biggest change in the volatile mixture for aphid-stressed plants was a large increase (from 1.4 to 7.9 ppb) in sesquiterpenes-particularly acyclic sesquiterpenes, such as the farnesene isomers. Acyclic sesquiterpenes had different effects on SOA production depending on the chemical mechanism. Farnesenes suppressed SOA formation from ozonolysis with a 9.7-14.6% SOA mass yield from healthy plant emissions and a 6.9-10.4% SOA mass yield from aphid-stressed plant emissions. Ozonolysis of volatile mixtures containing more farnesenes promoted fragmentation reactions, which produced higher volatility oxidation products. In contrast, plant volatile mixtures containing more farnesenes did not appreciably change SOA production from photooxidation. SOA mass yields ranged from 10.8 to 23.2% from healthy plant emissions and 17.8-26.8% for aphid-stressed plant emissions. This study highlights the potential importance of acyclic terpene chemistry in a future climate regime with an increased presence of plant stress volatiles