ABSTRACT
PURPOSE: Identifying molecular and immune features to guide immune checkpoint inhibitor (ICI)-based regimens remains an unmet clinical need. EXPERIMENTAL DESIGN: Tissue and longitudinal blood specimens from phase III trial S1400I in patients with metastatic squamous non-small cell carcinoma (SqNSCLC) treated with nivolumab monotherapy (nivo) or nivolumab plus ipilimumab (nivo+ipi) were subjected to multi-omics analyses including multiplex immunofluorescence (mIF), nCounter PanCancer Immune Profiling Panel, whole-exome sequencing, and Olink. RESULTS: Higher immune scores from immune gene expression profiling or immune cell infiltration by mIF were associated with response to ICIs and improved survival, except regulatory T cells, which were associated with worse overall survival (OS) for patients receiving nivo+ipi. Immune cell density and closer proximity of CD8+GZB+ T cells to malignant cells were associated with superior progression-free survival and OS. The cold immune landscape of NSCLC was associated with a higher level of chromosomal copy-number variation (CNV) burden. Patients with LRP1B-mutant tumors had a shorter survival than patients with LRP1B-wild-type tumors. Olink assays revealed soluble proteins such as LAMP3 increased in responders while IL6 and CXCL13 increased in nonresponders. Upregulation of serum CXCL13, MMP12, CSF-1, and IL8 were associated with worse survival before radiologic progression. CONCLUSIONS: The frequency, distribution, and clustering of immune cells relative to malignant ones can impact ICI efficacy in patients with SqNSCLC. High CNV burden may contribute to the cold immune microenvironment. Soluble inflammation/immune-related proteins in the blood have the potential to monitor therapeutic benefit from ICI treatment in patients with SqNSCLC.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Carcinoma, Squamous Cell , Lung Neoplasms , Humans , Nivolumab , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Multiomics , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/genetics , Carcinoma, Squamous Cell/drug therapy , Carcinoma, Squamous Cell/genetics , Immunotherapy , Lung/pathology , Epithelial Cells/pathology , Ipilimumab/therapeutic use , Tumor MicroenvironmentABSTRACT
Chimeric antigen receptor T cells (CAR-Ts) have remarkable efficacy in liquid tumors, but limited responses in solid tumors. We conducted a Phase I trial (NCT02107963) of GD2 CAR-Ts (GD2-CAR.OX40.28.z.iC9), demonstrating feasibility and safety of administration in children and young adults with osteosarcoma and neuroblastoma. Since CAR-T efficacy requires adequate CAR-T expansion, patients were grouped into good or poor expanders across dose levels. Patient samples were evaluated by multi-dimensional proteomic, transcriptomic, and epigenetic analyses. T cell assessments identified naive T cells in pre-treatment apheresis associated with good expansion, and exhausted T cells in CAR-T products with poor expansion. Myeloid cell assessment identified CXCR3+ monocytes in pre-treatment apheresis associated with good expansion. Longitudinal analysis of post-treatment samples identified increased CXCR3- classical monocytes in all groups as CAR-T numbers waned. Together, our data uncover mediators of CAR-T biology and correlates of expansion that could be utilized to advance immunotherapies for solid tumor patients.
Subject(s)
Neuroblastoma , Receptors, Chimeric Antigen , Child , Young Adult , Humans , Receptors, Chimeric Antigen/genetics , Receptors, Antigen, T-Cell/genetics , Proteomics , Immunotherapy, Adoptive/adverse effects , Immunotherapy, Adoptive/methods , T-Lymphocytes , Neuroblastoma/pathology , Cell- and Tissue-Based TherapyABSTRACT
BACKGROUND: Some oldest-old individuals can maintain superior cognition despite advanced age. Little is known about the neuropathological changes in the brains of oldest-old superior cognitive performers. OBJECTIVE: Our objective was to examine the associations between Alzheimer's disease (AD) and non-AD neuropathologic features in relation to superior cognitive performance in oldest-old individuals. METHODS: We analyzed brain autopsy data from 102 participants with normal cognition from The 90+ Study. Superior global cognitive performers (SGCP) were defined as having Mini-Mental State Examination (MMSE) score ≥28 in the last visit 12 to 2 months before death. To examine the associations between individual and multiple comorbid neuropathologic features with SGCP status we used multiple logistic regression models adjusting for age, sex, and education. RESULTS: Alzheimer's disease neuropathological change (ADNC) and low levels of vascular pathologic change were not associated with superior cognition. In contrast, participants with limbic (ORâ=â8.37; 95% CI: 1.48-47.44) and neocortical (ORâ=â10.80;95% CI: 1.03-113.82) Lewy body disease (LBD), or with hippocampal sclerosis (HS) (ORâ=â5.28; 95% CI: 1.10-25.47) were more likely to be non-SGCP. High total burden of multiple comorbid neuropathologic features was associated with a lower likelihood of being SGCP. CONCLUSION: Oldest-old superior cognitive performers were resilient to ADNC and low levels of vascular pathologic change and were resistant to non-AD neurodegenerative changes and multiple comorbid neuropathologic features. Understanding the factors underlying the ability of superior cognitive performers to resist these changes might provide useful insights on maintenance of superior cognition despite advanced age.
Subject(s)
Alzheimer Disease , Lewy Body Disease , Humans , Aged, 80 and over , Alzheimer Disease/pathology , Cognition , Brain/pathology , Lewy Body Disease/pathologyABSTRACT
INTRODUCTION: The association between neuropathological changes and dementia among centenarians and nonagenarians remains unclear. METHODS: We examined brain tissue from 100 centenarians and 297 nonagenarians from The 90+ Study, a community-based longitudinal study of aging. We determined the prevalence of 10 neuropathological changes and compared their associations with dementia and cognitive performance between centenarians and nonagenarians. RESULTS: A total of 59% of centenarians and 47% of nonagenarians had at least four neuropathological changes. In centenarians, neuropathological changes were associated with higher odds of dementia and, compared to nonagenarians, the odds were not attenuated. For each additional neuropathological change, the Mini-Mental State Examination score was lower by 2 points for both groups. DISCUSSION: Neuropathological changes continue to be strongly related to dementia in centenarians, highlighting the importance of slowing or preventing the development of multiple neuropathological changes in the aging brain to maintain cognitive health. HIGHLIGHTS: Individual and multiple neuropathological changes are frequent in centenarians. These neuropathological changes are strongly associated with dementia. There is no attenuation of this association with age.
Subject(s)
Centenarians , Dementia , Aged, 80 and over , Humans , Longitudinal Studies , Aging , Brain , Dementia/epidemiology , Dementia/diagnosisABSTRACT
AIMS/HYPOTHESIS: Identifying risk factors for tinnitus could facilitate not only the recommendations for prevention measures, but also identifying potential pathways for new interventions. This study reports the first comprehensive systematic review of analytical observational studies able to provide information about causality (i.e., case-control and cohort designs). METHODS: A literature search of four electronic databases identified epidemiological studies published on tinnitus and different exposures. Independent raters screened all studies, extracted data, and evaluated study quality using the Newcastle-Ottawa Scale. Reported relative risks (RR), hazard ratios (HR), odds ratios (OR), and prevalence ratios (PR) with 95% confidence intervals (CI) were used to compute crude estimates of RR for tinnitus risk factors. RESULTS: From 2389 records identified, a total of 374 articles were read as full text (24 reviews, 301 cross-sectional studies, 42 cohort studies, and 7 case-control studies). However, from 49 case-control and cohort studies, only 25 adequately reported risk ratios. Using the findings from these studies, positive causal associations were found for various hearing-related factors (i.e., unspecified hearing loss, sensorineural hearing loss, occupational noise exposure, ototoxic platinum therapy, and otitis media). Evidence was also found for a number of non-otological risk factors including temporo-mandibular joint disorder, depression, chronic obstructive pulmonary disease, and hyperlipidemia. Negative associations indicating preventative effects were found for diabetes and high alcohol consumption. No associations were found for low alcohol consumption, body mass index, head injury, heart failure, hypertension, leisure noise exposure, migraine, rheumatoid arthritis, sex, smoking, stroke, and whiplash. However, with the exception of unspecified hearing loss, these findings resulted from pooling no more than 4 studies, illustrating that the vast majority of the associations still remain inconclusive. CONCLUSIONS: These systematic review and meta-analysis confirm a number of otological and non-otological risk factors for tinnitus. By highlighting major gaps in knowledge, our synthesis can help provide direction for future research that will shed light on the pathophysiology, improve management strategies, and inform more effective preventions.
Subject(s)
Hearing Loss, Sensorineural , Hearing Loss , Tinnitus , Humans , Tinnitus/epidemiology , Tinnitus/etiology , Cross-Sectional Studies , Hearing Loss/epidemiology , Hearing Loss/etiology , Risk Factors , Observational Studies as TopicABSTRACT
[This corrects the article DOI: 10.3389/fnagi.2021.647285.].
ABSTRACT
INTRODUCTION: Tinnitus is a symptom and not a disease in its own right. A number of medical conditions are known to increase the risk of developing tinnitus. Most known risk factors are otological or neurological, but general health and lifestyle can also precipitate the condition. Understanding these modifiable risk factors can help to identify vulnerable groups and can inform preventive actions to reduce likelihood of developing tinnitus. Smoking, alcohol consumption, body mass index (BMI) and caffeine intake are all lifestyle risk factors hypothesized to be related to tinnitus. Nonetheless, research findings in support of those relationships are somewhat mixed. METHODS: A systematic review was conducted to identify all relevant studies on the specific risk factors. Findings were summarized using a narrative synthesis and meta-analysis, where possible. RESULTS: Overall 384 studies were included, mostly using cross-sectional designs. Findings indicated significantly increased risk of tinnitus among current (based on 26 studies) and ever smokers (based on 16 studies) and among obese people (based on seven studies), but no effect of alcohol consumption (based on 11 studies). With respect to caffeine intake or coffee drinking, only three studies examined this risk factor and so we were unable to draw conclusions. CONCLUSION: Our results contribute to quantifying the relationship between tinnitus and specific lifestyle-related risk factors, and we highlight some of the gaps and inconsistencies across published studies.
Subject(s)
Caffeine , Tinnitus , Body Mass Index , Caffeine/adverse effects , Cross-Sectional Studies , Humans , Life Style , Risk Factors , Smoking , Tinnitus/epidemiology , Tinnitus/etiologyABSTRACT
Tinnitus can be a burdensome condition on both individual and societal levels. Many aspects of this condition remain elusive, including its underlying mechanisms, ultimately hindering the development of a cure. Interdisciplinary approaches are required to overcome long-established research challenges. This review summarizes current knowledge in various tinnitus-relevant research fields including tinnitus generating mechanisms, heterogeneity, epidemiology, assessment, and treatment development, in an effort to highlight the main challenges and provide suggestions for future research to overcome them. Four common themes across different areas were identified as future research direction: (1) Further establishment of multicenter and multidisciplinary collaborations; (2) Systematic reviews and syntheses of existing knowledge; (3) Standardization of research methods including tinnitus assessment, data acquisition, and data analysis protocols; (4) The design of studies with large sample sizes and the creation of large tinnitus-specific databases that would allow in-depth exploration of tinnitus heterogeneity.
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This volume has highlighted the many recent advances in tinnitus theory, models, diagnostics, therapies, and therapeutics. But tinnitus knowledge is far from complete. In this chapter, contributors to the Behavioral Neuroscience of Tinnitus consider emerging topics and areas of research needed in light of recent findings. New research avenues and methods to explore are discussed. Issues pertaining to current assessment, treatment, and research methods are outlined, along with recommendations on new avenues to explore with research.
Subject(s)
Neurosciences , Tinnitus , Humans , Tinnitus/therapyABSTRACT
Background: The Marie-Sklodowska-Curie Actions' (MSCA) Innovative Training Network (ITN) is a doctoral training programme jointly implemented by academic institutions and industries from countries across Europe and beyond. To our knowledge no study has examined the experience of students participating in MSCA-ITNs. This study aims to evaluate and report MSCA-ITN Early Stage Researcher (ESR) experiences. Methods: The Innovative Training Network - Evaluation Questionnaire (ITN-EQ) was developed to assess supervision, training, collaborations and experiences of ESRs and forwarded to two tinnitus-related ITNs and seven ITNs of other disciplines. Results: Key advantages identified included better career prospects, multidisciplinary research opportunities/collaborations, international exposure, personal/professional development, plus generous salaries and research budgets. However, lack of a common EU framework resulted in the experience being largely dependent on the host institution, country and supervisor. Moreover, managing the dual requirements of ITNs and host institutions while completing a three-year PhD seemed challenging for most ESRs. ESR involvement in workshop and training school planning was desirable. More than 80% of ESRs rated the overall ITN experience favourably and 98.3% would recommend the same to prospective PhD students. Conclusions: This report could provide valuable insights in planning and management of future ITNs and could assist prospective students in their decision of joining an ITN for their PhD.
ABSTRACT
How many people are affected by tinnitus? Is the risk of developing tinnitus on the rise or has it been declining over time? What modifiable lifestyle factors could help to prevent tinnitus? These population-based questions can be addressed through epidemiological research. Epidemiology refers to the underlying and basic science of public health. It describes the study of the distribution and determinants of health-related states or events in specified populations and the application of this study to the control of health problems. There are two key concepts in epidemiology: (1) measures of frequency and (2) measures of effect. In this chapter, we introduce the two main measures of frequency, prevalence and incidence. We also introduce the notion of risk factors, critical for understanding measures of effect concerning the risk of developing a health condition. In both sections, we provide illustrative examples from the published literature on tinnitus. We end by offering a critical evaluation of the current status of epidemiological research on tinnitus and point to some promising future directions.
Subject(s)
Tinnitus , Humans , Incidence , Prevalence , Risk Factors , Tinnitus/epidemiology , Tinnitus/etiologyABSTRACT
BACKGROUND: Intestinal and multivisceral transplantations are treatment options for patients with intestinal failure. Transplantation is often complicated by abdominal and/or bloodstream infections in the post-operative period. METHODS: A retrospective chart review of all adults who underwent intestinal or multivisceral transplantation at our institution from 2003 to 2015 was performed. Data were collected for 2 years post transplant. RESULTS: A total of 106 intestinal or multivisceral transplants were performed in 103 patients. The median age at the time of transplant was 44 (IQR: 34-52) with 55% (n = 58) male and 45% (n = 48) female. There were 46 (43%) intra-abdominal infections post transplant among the 103 patients, and six transplant recipients (13%) developed concurrent bloodstream infections. The median time to first intra-abdominal infection was 23 days (IQR: 10-48). For those with organisms isolated in culture, forty-seven percent of the isolates were gram negative, 39% gram positive, 7% anaerobes, and 7% yeast. The most common isolates were enterococci at 28%, E. coli at 14%, and Klebsiella spp at 13%. Sixty-three percent of the enterococci were vancomycin-resistant enterococci (VRE), and 22% of the gram-negative isolates were extended spectrum beta-lactamases (ESBLs). Patients with intra-abdominal infections had longer hospital post-transplant length of stays at a median of 35 days (IQR: 25-48) vs 23 days (IQR: 17-33) for those without infections, P = .0012. There was no difference in all-cause mortality in patients with or without intra-abdominal infections, P = .654. CONCLUSIONS: Intra-abdominal infections are common in intestinal or multivisceral transplant recipients, but despite this complication, we found no increased risk of mortality. These transplant recipients are also at risk for infection with drug-resistant organisms.
Subject(s)
Intraabdominal Infections/etiology , Organ Transplantation/adverse effects , Transplant Recipients/statistics & numerical data , Adult , Anti-Bacterial Agents/therapeutic use , Bacteremia/etiology , Bacteria/classification , Bacteria/drug effects , Bacteria/isolation & purification , Female , Humans , Intestines/transplantation , Male , Middle Aged , Postoperative Period , Retrospective StudiesSubject(s)
Suicide, Attempted/statistics & numerical data , Tinnitus/psychology , Adult , Age Distribution , Aged , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Self Report , Sex Distribution , Suicide, Attempted/psychology , Surveys and Questionnaires , Sweden/epidemiology , Tinnitus/epidemiologyABSTRACT
INTRODUCTION: Prevalence estimates depend largely on the nature of the question asked to define the presence of the health condition, and the literature on the population burden of tinnitus and hearing difficulties is no different in this respect. The lack of standardized questions for data collection limits comparison across studies and across countries. The purpose of this short Technical Note is to report the first attempt to establish a set of standard questions developed for use in population-based surveys, and their adaptation and translation from English into 11 European languages. METHODS: Four questions and their corresponding response options were adapted from existing population-based surveys to assess tinnitus prevalence, tinnitus symptom severity, use of healthcare resources for tinnitus and hearing difficulty. The translated versions (Bulgarian, French, German, Greek, Italian, Latvian, Polish, Portuguese, Romanian, Russian, and Spanish) were generated using recognized methods to achieve a "world-for-world" translation. RESULTS: Translated versions were produced with acceptable functional equivalence to the original English-language version, as judged by a small panel of bilingual speakers who participated in the online field testing. CONCLUSION: This work is the first of its kind to promote multi-national standardization by creating a set of tools that can readily be used across countries. These are currently being used in a European-wide study of tinnitus prevalence, and have wider application across English- and Spanish speaking countries including the Americas and Oceania.
Subject(s)
Health Resources , Hearing Loss/diagnosis , Hearing , Self Report/standards , Tinnitus/diagnosis , Translating , Cultural Characteristics , Europe/epidemiology , Hearing Loss/epidemiology , Hearing Loss/physiopathology , Hearing Loss/therapy , Humans , Predictive Value of Tests , Prevalence , Reproducibility of Results , Severity of Illness Index , Tinnitus/epidemiology , Tinnitus/physiopathology , Tinnitus/therapyABSTRACT
BACKGROUND: The heterogeneity of tinnitus is substantial. Its numerous pathophysiological mechanisms and clinical manifestations have hampered fundamental and treatment research significantly. A decade ago, the Tinnitus Research Initiative introduced the Tinnitus Sample Case History Questionnaire, a case history instrument for standardised collection of information about the characteristics of the tinnitus patient. Since then, a number of studies have been published which characterise individuals and groups using data collected with this questionnaire. However, its use has been restricted to a clinical setting and to the evaluation of people with tinnitus only. In addition, it is limited in the ability to capture relevant comorbidities and evaluate their temporal relationship with tinnitus. METHOD: Here we present a new case history instrument which is comprehensive in scope and can be answered by people with and without tinnitus alike. This 'European School for Interdisciplinary Tinnitus Research Screening Questionnaire' (ESIT-SQ) was developed with specific attention to questions about potential risk factors for tinnitus (including demographics, lifestyle, general medical and otological histories), and tinnitus characteristics (including perceptual characteristics, modulating factors, and associations with co-existing conditions). It was first developed in English, then translated into Dutch, German, Italian, Polish, Spanish, and Swedish, thus having broad applicability and supporting international collaboration. CONCLUSIONS: With respect to better understanding tinnitus profiles, we anticipate the ESIT-SQ to be a starting point for comprehensive multi-variate analyses of tinnitus. Data collected with the ESIT-SQ can allow establishment of patterns that distinguish tinnitus from non-tinnitus, and definition of common sets of tinnitus characteristics which might be indicated by the presence of otological or comorbid systemic diseases for which tinnitus is a known symptom.
Subject(s)
Hearing , Surveys and Questionnaires/standards , Tinnitus/diagnosis , Europe/epidemiology , Humans , Predictive Value of Tests , Reproducibility of Results , Risk Factors , Tinnitus/epidemiology , Tinnitus/physiopathology , TranslatingABSTRACT
A rise in new HIV diagnoses among older adults is characterized by poor prognosis and reduced survival times. Although heterosexual transmission remains the main route of infection in women, little is known regarding immune functions in the genital tract of postmenopausal women, especially those who are HIV positive. Furthermore, effects of hormone replacement therapy (HRT) on the genital tract immune system are unclear. Using the Women's Interagency HIV Study repository, we obtained cervical-vaginal lavage (CVL) samples from premenopausal and postmenopausal HIV-positive and HIV-negative women, some of whom were on HRT. Samples were assayed for interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-α, secretory leukocyte protease inhibitor (SLPI), Elafin, human beta defensin-2 (HBD2), and macrophage inflammatory protein (MIP)-3α using ELISA. Anti-HIV activity in CVL was measured using TZM-bl indicator cells. Among HIV-positive women, the plasma viral load was significantly higher and CD4 count was significantly lower in postmenopausal compared with premenopausal women. Postmenopausal women, irrespective of HIV status, had significantly lower levels of HBD2 compared with premenopausal women. Among the HIV-negative individuals, postmenopausal women had significantly lower levels of MIP-3α, IL-6, and SLPI compared with premenopausal women. In contrast, HIV-positive postmenopausal women had significantly higher levels of TNF-α compared with HIV-positive premenopausal women. In most cases, HRT groups resembled the postmenopausal groups. No significant differences in anti-HIV activity by menopausal or by HIV status were noted. Our findings indicate that the female genital tract immune microenvironment is distinct by menopausal status and HIV status. Further studies are needed to assess the risk of HIV acquisition/transmission in this population.
Subject(s)
Cytokines/analysis , Elafin/analysis , Genitalia, Female/immunology , HIV Infections/immunology , Postmenopause/immunology , Secretory Leukocyte Peptidase Inhibitor/analysis , beta-Defensins/analysis , Adult , CD4 Lymphocyte Count , Cross-Sectional Studies , Female , HIV-1/immunology , Hormone Replacement Therapy/adverse effects , Humans , Middle Aged , Premenopause/immunology , Prospective Studies , Vaginal Douching , Viral LoadABSTRACT
PROBLEM: Adolescent girls are disproportionately affected by the HIV/AIDS pandemic, accounting for 22% of all new HIV infections globally. Yet little is known regarding the immune microenvironment of the adolescent female reproductive tract, especially regarding differences among sexually active and inactive girls, a critical parameter to evaluate HIV susceptibility associated with young age and sexual debut. METHODS: Cervico-vaginal lavage (CVL) was collected from sexually active (10) and inactive (8) girls aged 11-19 years and analyzed by ELISA for inflammation-associated biomarkers IL-6, IL-8, TNF-α, MIP-3α, IL-1α, IL-1ß, matrix metalloproteinases (MMP) 1, 2, 7, 8, and 9, as well as anti-HIV mediators, Elafin, SLPI, human beta-defensin 2, and tissue inhibitor of matrix metalloproteinases (TIMP) 1 and 2. Cervical ectopy was analyzed using Volocity. Anti-HIV activity was determined by TZM-bl assay. Statistical analyses were performed using GraphPad Prism and R. RESULTS: Sexually inactive girls had significantly higher levels of TNF-α (P = .029) in CVL compared to sexually active girls. In contrast, sexually active girls showed a trend toward higher levels of IL-1α (P = .051) compared to the sexually inactive girls. Heat-map correlations between cervical ectopy and immune biomarkers were also distinct between the 2 populations with significant positive associations between % ectopy and inflammation-associated biomarkers IL-6, IL-1ß, IL-8, MIP-3α, MMP-8, and MMP-9 observed in the sexually inactive but not sexually active group. CONCLUSION: Higher pro-inflammatory biomarker TNF-α, as well as a distinct inflammation-associated immune clustering in sexually inactive girls, can potentially increase risk for infections including HIV upon sexual debut. Future studies with larger sample sizes are needed to characterize the immune parameters associated with sexual activity.
Subject(s)
Biomarkers/metabolism , Genitalia, Female/immunology , Genitalia, Female/metabolism , Genitalia, Female/virology , HIV-1/immunology , Reproduction/immunology , Sexual Behavior/physiology , Adolescent , Adult , Cytokines/immunology , Female , HIV Infections/immunology , Humans , Inflammation/immunology , Inflammation/metabolism , Vaginal Douching/methods , Young AdultABSTRACT
We study the use of nanopatterned silicon membranes to obtain optically-induced heating in water. We show that by varying the detuning between an absorptive optical resonance of the patterned membrane and an illumination laser, both the magnitude and response time of the temperature rise can be controlled. This allows for either sequential or selective heating of different patterned areas on chip. We obtain a steady-state temperature of approximately 100 °C for a 805.5nm CW laser power density of 66 µW/µm2 and observe microbubble formation. The ability to spatially and temporally control temperature on the microscale should enable the study of heat-induced effects in a variety of chemical and biological lab-on-chip applications.
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Due to their favorable materials properties including direct bandgap and high electron mobilities, epitaxially grown III-V compound semiconductors such as gallium arsenide (GaAs) provide unmatched performance over silicon in solar energy harvesting. Nonetheless, their large-scale deployment in terrestrial photovoltaics remains challenging mainly due to the high cost of growing device quality epitaxial materials. In this regard, reducing the thickness of constituent active materials under appropriate light management schemes is a conceptually viable option to lower the cost of GaAs solar cells. Here, we present a type of high efficiency, ultrathin GaAs solar cell that incorporates bifacial photon management enabled by techniques of transfer printing to maximize the absorption and photovoltaic performance without compromising the optimized electronic configuration of planar devices. Nanoimprint lithography and dry etching of titanium dioxide (TiO2) deposited directly on the window layer of GaAs solar cells formed hexagonal arrays of nanoscale posts that serve as lossless photonic nanostructures for antireflection, diffraction, and light trapping in conjunction with a co-integrated rear-surface reflector. Systematic studies on optical and electrical properties and photovoltaic performance in experiments, as well as numerical modeling, quantitatively describe the optimal design rules for ultrathin, nanostructured GaAs solar cells and their integrated modules.
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Lipid bilayers form the boundaries of the cell and its organelles. Many physiological processes, such as cell movement and division, involve bending and folding of the bilayer at high curvatures. Currently, bending of the bilayer is treated as an elastic deformation, such that its stress-strain response is independent of the rate at which bending strain is applied. We present here the first direct measurement of viscoelastic response in a lipid bilayer vesicle. We used a dual-beam optical trap (DBOT) to stretch 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) giant unilamellar vesicles (GUVs). Upon application of a step optical force, the vesicle membrane deforms in two regimes: a fast, instantaneous area increase, followed by a much slower stretching to an eventual plateau deformation. From measurements of dozens of GUVs, the average time constant of the slower stretching response was 0.225 ± 0.033 s (standard deviation, SD). Increasing the fluid viscosity did not affect the observed time constant. We performed a set of experiments to rule out heating by laser absorption as a cause of the transient behavior. Thus, we demonstrate here that the bending deformation of lipid bilayer membranes should be treated as viscoelastic.