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Open Access Publications from the University of California

Scholarly Works (72 results)

    LBL Publications (1995)
      Cover page: Study of Clusters Using Negative Ion Photodetachment Spectroscopy
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      UC San Diego Previously Published Works (2023)
        Cover page: Shape prediction on the basis of spectrum using neural networksCreative Commons 'BY' version 4.0 license
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        UC Davis Previously Published Works (2015)
        Previous work successfully implemented a novel system that uses a single particle mass spectrometer to conditionally sample size-segregated, source-oriented particles from the ambient atmosphere in real-time. The underlying hypothesis is that the composition of individual particles is a metric of particle source and thus sampling particles based on composition should be synonymous with sampling based on source. System operation relies on real-time pattern recognition to control the actuation of different ChemVol samplers, where each ChemVol is associated with a unique composition signature. In the current work, a synthesis of data collected during these studies is used in retrospect to reconcile the actual source combinations contributing to the particles collected by each ChemVol. Source attribution is based on correlations between ChemVol sampling periods and coincident wind direction and temporal emissions patterns, coupled to knowledge of single particle composition and surrounding sources. Residential and commercial cooking, vehicular emissions, residential heating and highly processed regional background PM were identified as the major sources. Results show that real-time patterns in single particle mixing state correctly identified specific sources and that these sources were successfully separated into different ChemVols for both summer and winter seasons.
          Cover page: Retrospective source attribution for source-oriented sampling
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          UC San Diego Previously Published Works (2023)
          Scanning near-field optical microscopy is one of the most effective techniques for spectroscopy of nanoscale systems. However, inferring optical constants from the measured near-field signal can be challenging because of a complicated and highly nonlinear interaction between the scanned probe and the sample. Conventional fitting methods applied to this problem often suffer from the lack of convergence or require human intervention. Here, we develop an alternative approach where the optical parameter extraction is automated by a deep learning network. The network provides an initial estimate that is subsequently refined by a traditional fitting algorithm. We show that this method demonstrates superior accuracy, stability against noise, and computational speed when applied to simulated near-field spectra.
            Cover page: Deep-learning-aided extraction of optical constants in scanning near-field optical microscopyCreative Commons 'BY' version 4.0 license
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            UC Irvine Previously Published Works (2009)
            The traction forces exerted by an adherent cell on a substrate have been studied only in the two-dimensions (2D) tangential to substrate surface (Txy). We developed a novel technique to measure the three-dimensional (3D) traction forces exerted by live bovine aortic endothelial cells (BAECs) on polyacrylamide deformable substrate. On 3D images acquired by confocal microscopy, displacements were determined with image-processing programs, and traction forces in tangential (XY) and normal (Z) directions were computed by finite element method (FEM). BAECs generated traction force in normal direction (Tz) with an order of magnitude comparable to Txy. Tz is upward at the cell edge and downward under the nucleus, changing continuously with a sign reversal between cell edge and nucleus edge. The method was evaluated regarding accuracy and precision of displacement measurements, effects of FE mesh size, displacement noises, and simple bootstrapping. These results provide new insights into cell-matrix interactions in terms of spatial and temporal variations in traction forces in 3D. This technique can be applied to study live cells to assess their biomechanical dynamics in conjunction with biochemical and functional activities, for investigating cellular functions in health and disease.
              Cover page: Live Cells Exert 3-Dimensional Traction Forces on Their SubstrataCreative Commons 'BY' version 4.0 license
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              UC Irvine Previously Published Works (2001)

              Background

              Optical Doppler tomography (ODT) combines laser Doppler flowmetry with optical coherence tomography to obtain high-resolution images of blood flow in human skin in situ and in real time.

              Observations

              We present a case in which ODT was used on a patient with a port-wine stain (PWS) birthmark to document the change of blood flow in response to laser therapy. It might be possible to use ODT blood flow measurements in situ to assist in assessing the efficacy of laser PWS therapy. If partial restoration of flow occurs immediately or shortly after laser exposure, indicative of reperfusion due to inadequate blood vessel injury, the PWS can be retreated using higher light dosages. Retreatment is continued until the measured Doppler shift is zero due to a permanent reduction in blood flow, indicative of irreversible microthrombus formation in the PWS vessels.

              Conclusions

              We have demonstrated that ODT may be used for noninvasive imaging of blood vessels in PWS skin. Moreover, ODT will potentially allow laser therapy to be optimized on an individual patient basis by providing a fast, semiquantitative evaluation of the efficacy of PWS laser therapy in situ and in real time.
                Cover page: Imaging blood flow in human port-wine stain in situ and in real time using optical Doppler tomography.Creative Commons 'BY' version 4.0 license
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                Dermatology Online Journal, Volume 22, Issue 2 (2016)
                Psoriasis patients often report dissatisfaction with treatment. However, it is less clear how the severity of key psoriasis symptoms (painful skin, itching, and scaling) as well as overall disease severity influence patient dissatisfaction levels. Using the Adelphi 2011/2013 Psoriasis Disease Specific Programmes, two “real world” surveys of US dermatologists and their patients, patient satisfaction was evaluated. Dermatologists provided data on disease characteristics, while patients indicated their satisfaction with existing treatment. Physician-reported severity (none, mild, moderate/severe) of psoriasis-related itching, pain, and scaling, overall disease severity (mild, moderate and severe) and therapy type were compared by patient satisfaction levels (satisfied vs. dissatisfied). Multivariate regressions examined the relationship between patient satisfaction, clinical symptoms, and psoriasis overall disease severity, controlling for differences in patient demographics and comorbidities. The sample comprised 633 psoriasis patients (56% male) with a mean age of 45. Overall, 18% of patients reported dissatisfaction with their psoriasis treatment. Dissatisfied patients were more likely to have moderate (65% vs. 40%) or severe (21% vs 3%) psoriasis compared to patients who were satisfied (both p<0.05). Dissatisfied patients were also more likely to have more severe pain (30% moderate-to-severe pain vs. 9%), more severe itching (61% moderate-to-severe itching vs. 25%), and more severe scaling (68% moderate-to-severe scaling vs. 33%) than satisfied patients (all p< 0.05). Multivariate analyses confirmed these results. Clinicians should be aware that some psoriasis patients, especially those with severe overall disease or symptoms, may be dissatisfied and are in need of better treatment.
                  Cover page: Patient satisfaction with current psoriasis treatment: a real-world study in the USACreative Commons 'BY-NC-ND' version 4.0 license
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                  Dermatology Online Journal, Volume 21, Issue 10 (2015)

                  Background: Psoriasis patients report that this disease can impact on their health-related quality of life (HR-QoL) and work productivity. It is important to understand how this is influenced by the clinical characteristics of psoriasis such as symptom severity. Common symptoms include itching, pain, and scaling but the psychosocial impact these features have on patients is not well understood.

                  Objective: To explore the impact of psoriasis symptoms (itching, pain, and scaling) on HR-QoL and work productivity.

                  Method: Data were extracted from the Adelphi 2011 and 2013 Psoriasis Disease Specific Programmes – two real world surveys of US dermatologists and their psoriasis patients.  HR-QoL was measured using the Dermatology Life Quality Index (DLQI) and EuroQOL 5-Dimension Health Questionnaire (EQ-5D). Work productivity loss was measured by the Work Productivity and Activity Impairment (WPAI) questionnaire. The impact of symptom severity (none, mild, moderate/severe) for itching, pain, and scaling on DLQI, EQ-5D, and WPAI scores were examined, controlling for differences in demographics and co-morbidities.

                  Results: Patient mean age was 44 years and 55% were male. Moderate/severe itching, pain, and scaling were experienced by 33%, 13%, and 41% of patients, respectively. Controlling for differences in demographics and co-morbidities, increased symptom severity was associated with reduced HR-QoL. Accordingly, EQ-5D scores decreased with itching severity (moderate/severe vs. none: -0.07; 95% confidence interval [CI] =-0.09, -0.04), whereas DLQI scores increased (moderate/severe versus none: 4.9; CI = 3.9, 5.9) (both p<0.05). WPAI scores increased with itching severity, indicating increased work productivity loss (moderate/severe versus none: 17.6, CI = 11.8, 23.5, p<0.05). The same pattern was observed for pain and scaling.

                  Conclusions: Among the patients studied, increased severity of psoriasis-related itching, pain, and scaling was associated with reduced health-related QoL and work productivity.

                    Cover page: Increased severity of itching, pain, and scaling in psoriasis patients is associated with increased disease severity, reduced quality of life, and reduced work productivityCreative Commons 'BY-NC-ND' version 4.0 license
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                    UC San Francisco Previously Published Works (2012)

                    Background and objectives

                    Src family kinases (SFKs) play a critical role in initiating and propagating signals in platelets. The aims of this study were to quantitate SFK members present in platelets and to analyze their contribution to platelet regulation using glycoprotein VI (GPVI) and intregrin αIIbβ3, and in vivo.

                    Methods and results

                    Mouse platelets express four SFKs, Fgr, Fyn, Lyn and Src, with Lyn expressed at a considerably higher level than the others. Using mutant mouse models, we demonstrate that platelet activation by collagen-related peptide (CRP) is delayed and then potentiated in the absence of Lyn, but only marginally reduced in the absence of Fyn or Fgr, and unaltered in the absence of Src. Compound deletions of Lyn/Src or Fyn/Lyn, but not of Fyn/Src or Fgr/Lyn, exhibit a greater delay in activation relative to Lyn-deficient platelets. Fibrinogen-adherent platelets show reduced spreading in the absence of Src, potentiation in the absence of Lyn, but no change in the absence of Fyn or Fgr. In mice double-deficient in Lyn/Src or Fgr/Lyn, the inhibitory role of Lyn on spreading on fibrinogen is lost. Lyn is the major SFK-mediating platelet aggregation on collagen at arterial shear and its absence leads to a reduction in thrombus size in a laser injury model.

                    Conclusion

                    These results demonstrate that SFKs share individual and overlapping roles in regulating platelet activation, with Lyn having a dual role in regulating GPVI signaling and an inhibitory role downstream of αIIbβ3, which requires prior signaling through Src.
                      Cover page: Distinct and overlapping functional roles of Src family kinases in mouse platelets
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                      Dermatology Online Journal, Volume 22, Issue 7 (2016)

                      Psoriasis patients often report dissatisfaction with treatment. However, the extent to which patients and their treating dermatologists are aligned regarding satisfaction with psoriasis therapy is largely unknown. This was explored using data derived from the Adelphi 2011/2013 Psoriasis Disease Specific Programmes, two real world surveys of US dermatologists and their patients. Physicians and patients independently reported their satisfaction with psoriasis control (satisfied, dissatisfied). Two levels of satisfaction alignment between physician and patient responses were constructed: aligned (same responses) and misaligned (different responses). In addition, dermatologists provided patient treatment history and disease/symptom severity whereas patients reported data on health-related quality of life (HRQoL), using the EuroQOL 5-Dimension Health Questionnaire (EQ-5D) and Dermatology Life Quality Index (DLQI), and work productivity using the Work Productivity Activity index (WPAI). Multivariate regressions were employed to examine the relationship between satisfaction alignment, overall disease and symptom severity, HRQoL, and work productivity controlling for differences in patient demographics and comorbidities.

                      From 627 paired dermatologist and psoriasis patient records, 512 (81.7%) and 115 (18.3%) cases fell into the ‘aligned’ and ‘misaligned’ groups, respectively. Compared with patients in the aligned group, those in the misaligned group had more moderate to severe psoriasis (82.3% vs. 43.7%), moderate to severe itching (45.6% vs. 27.8%), pain (23.0% vs. 10.6%), and scaling (54.8% vs. 36.1%), and had lower current biologics use (27.0% vs. 42%) (all p<0.05). The misaligned group was associated with reduced HRQoL (lower EQ-5D score: 0.86 vs. 0.91; higher DLQI score: 7.06 vs. 4.23) and greater work productivity loss (higher WPAI scores: 18.27 vs. 11.43) (all p<0.05). Multivariate analyses confirmed these results (p<0.05). Almost 1 in 5 patients were misaligned with their dermatologist’s level of satisfaction with their psoriasis treatment; misalignment was associated with increased disease and symptom severity, reduced HRQoL, and reduced work productivity.

                        Cover page: Satisfaction with current psoriasis treatment: misalignment between physician and patient perceptionsCreative Commons 'BY-NC-ND' version 4.0 license
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