The scope of hospital medicine practice at night: a national survey of night shift hospitalists.

Introduction: Although in-person hospitalist presence, increasingly staffed by dedicated nocturnists, has become the norm overnight in the hospital, the scope of nocturnist practice and typical workload has not been defined. This study examines the clinical responsibilities and patient safety perceptions of hospitalists who work night shifts in the United States.Methods: In the fall of 2019, a cross-sectional, web-based survey was administered to physician and nurse practitioner/physician assistant (NP/PA) hospitalists who work night shifts. The questionnaire assessed night staffing structure, typical responsibilities, patient volume, perceptions of safety overnight, as well as demographic information. The survey was posted on the Society of Hospital Medicine (SHM) Hospital Medicine Exchange (HMX) Online Discussion Forum. Additionally, the survey was distributed by 'snowball method' by respondents to other night hospitalists. Responses were collected anonymously.Results: Of the 167 respondents, 157 reported working night shifts. There was at least one respondent from 32 different states. In addition to performing admissions to medicine services and covering inpatients, night hospitalists cover ICU patients, participate in RRT/Code teams and procedure teams, perform consults, participate in medical education, and take outpatient calls. Across institutions, there was a large distribution in numbers of patients covered in a night shift; however, patient volume fell into typical ranges: 5-10 admissions for physicians, 0-6 admissions for NP/PAs, and 25-75 patient cross-coverage census. When physicians perform more than five admissions per night, hospitalists were less likely to agree that they could provide safe care (88% vs. 63%, p = 0.0006).Conclusions: This is the first national study to examine the clinical responsibilities of hospitalists working overnight. Overnight responsibilities are heterogeneous across institutions. As hospitals are increasingly employing nocturnists, more research is needed to guide night staffing and optimize patient safety.

Staff Experiences at a New York City Medical Center During the Spring Peak of the Covid-19 Pandemic: A Qualitative Study.

Purpose: In March-April 2020, New York City was overwhelmed by COVID-19 infections, leading to substantial disruptions in nearly all aspects of care and operations at most local hospitals. This qualitative study of a quaternary, urban oncology hospital investigated the effects of these disruptions upon a professionally diverse cohort of its employees, including physicians, nurses, respiratory therapists, pharmacists, security guards, histology technicians, and environmental services workers. Methods: The participant pool were selected through a combination of purposive and random sampling methodology and coders performed a thematic content analysis of open-ended responses. Results: Analysis revealed several important themes, including concerns about exposure for self and others; patient care as a source of both satisfaction and stress; psychological consequences of uncertainty and ambiguity; family as sources of both comfort and apprehension; the importance of adequate institutional communication; and support from colleagues. Conclusion: Results and analysis provide suggestions for institutional policies and initiatives in the event of a COVID-19 surge or another public health crisis. Administrative efforts should aspire to establish, strengthen, and promote interdisciplinary and interdepartmental efforts to address, and mitigate workplace and personal stressors. through timely and transparent communications, consistent clinical guidance and information about changes in hospital policies and supplemental employee assistance.

Palliative, Ethics, and End-of-Life Care Issues in the Cancer Patient.

End-of-life care of critically ill adult patients with advanced or incurable cancers is imbued with major ethical challenges. Oncologists, hospitalists, and intensivists can inadvertently subjugate themselves to the perceived powers of autonomous patients. Therapeutic illusion and poor insight by surrogates in physicians' ability to offer accurate prognosis, missed opportunities and miscommunication by clinicians, and lack of systematic or protocolized approach represent important barriers to high-quality palliative care. Enhanced collaboration, models that allow clinicians and surrogates to share the burdens of decision, and institutional support for early integration of palliative care can foster an ethical climate.

Phase II study of trastuzumab with modified docetaxel, cisplatin, and 5 fluorouracil in metastatic HER2-positive gastric cancer.

BACKGROUND: Trastuzumab with cisplatin and fluoropyrimidine is the standard treatment in metastatic HER2-positive gastric or gastroesophageal (GE) junction adenocarcinoma; however, there is limited data on the efficacy of trastuzumab in combination with a three-drug regimen in this setting. We examined the efficacy and safety of modified docetaxel, cisplatin and 5 fluorouracil (mDCF) plus trastuzumab in a single-arm multicenter phase II trial. METHODS: Previously untreated patients with HER2-positive metastatic gastric or GE junction adenocarcinoma were treated with mDCF and trastuzumab every 2 weeks. The primary endpoint was 6-month progression-free survival (PFS); secondary endpoints included objective response rate, overall survival (OS), and toxicity. RESULTS: We enrolled 26 patients with metastatic HER2-positive gastric or GE junction adenocarcinoma between February 2011 and June 2015. The median age of patients was 62 years; 96% had a Karnofsky performance status equal to or greater than 80%. With a median follow-up of 25.4 months, the 6-month PFS was 73% (95% CI 51-86%). The objective response rate was 65%, the median PFS was 13 months (95% CI 6.4-20.7) and the median OS was 24.9 months (95% CI 14.4-42.5). Grade 3/4 toxicities included neutropenia (42%), fatigue (23%), and hypophosphatemia (15%). There were no episodes of febrile neutropenia. CONCLUSION: The combination of mDCF and trastuzumab is effective and safe in patients with metastatic HER2-positive gastric or GE junction adenocarcinoma and can be considered as an option for selected patients. This trial is registered at ClinicalTrials.gov, number NCT00515411.

Room Temperature Electrochemical Synthesis of Crystalline GaOOH Nanoparticles from Expanding Liquid Metals.

Gallium oxyhydroxide (GaOOH) is a wide band gap semiconductor of interest for a variety of applications in electronics and catalysis where the synthesis of the crystalline form is usually achieved via hydrothermal routes. Here we synthesize GaOOH via the electrochemical oxidation of gallium based liquid metals in solutions of 0.1 M NaNO3 electrolyte with pH adjusted over the range of 7-8.4 with NaOH. This electrochemical approach employed under ambient conditions results in the formation of crystalline oblong shaped α-GaOOH nanoparticles from both liquid gallium and liquid galinstan which is a eutectic based on Ga, In, and Sn. The size and shape of the GaOOH particles could be controlled by the solution pH. The product is characterized with scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV-visible spectroscopy, and photoluminescence spectroscopy. During the electrochemical oxidation process, the liquid metal drop was found to expand significantly in the case of galinstan due to a constant electrowetting effect which resulted in the continuous expulsion of nanomaterial from the expanding liquid metal droplet. This electrochemical approach may be applicable to other liquid metals for the fabrication of metal oxide nanomaterials and also demonstrates that significant chemical reactions may be occurring at the surface of liquid metals that are actuated under an applied electric field in aqueous electrolytes.

Multicenter Prospective Phase II Trial of Neoadjuvant Dose-Dense Gemcitabine Plus Cisplatin in Patients With Muscle-Invasive Bladder Cancer.

Purpose Neoadjuvant chemotherapy followed by radical cystectomy (RC) is a standard of care for the management of muscle-invasive bladder cancer (MIBC). Dose-dense cisplatin-based regimens have yielded favorable outcomes compared with standard-dose chemotherapy, yet the optimal neoadjuvant regimen remains undefined. We assessed the efficacy and tolerability of six cycles of neoadjuvant dose-dense gemcitabine and cisplatin (ddGC) in patients with MIBC. Patients and Methods In this prospective, multicenter phase II study, patients received ddGC (gemcitabine 2,500 mg/m2 on day 1 and cisplatin 35 mg/m2 on days 1 and 2) every 2 weeks for 6 cycles followed by RC. The primary end point was pathologic downstaging to non-muscle-invasive disease (< pT2N0). Patients who did not undergo RC were deemed nonresponders. Pretreatment tumors underwent next-generation sequencing to identify predictors of chemosensitivity. Results Forty-nine patients were enrolled from three institutions. The primary end point was met, with 57% of 46 evaluable patients downstaged to < pT2N0. Pathologic response correlated with improved recurrence-free survival and overall survival. Nineteen patients (39%) required toxicity-related dose modifications. Sixty-seven percent of patients completed all six planned cycles. No patient failed to undergo RC as a result of chemotherapy-associated toxicities. The most frequent treatment-related toxicity was anemia (12%; grade 3). The presence of a presumed deleterious DNA damage response (DDR) gene alteration was associated with chemosensitivity (positive predictive value for < pT2N0 [89%]). No patient with a deleterious DDR gene alteration has experienced recurrence at a median follow-up of 2 years. Conclusion Six cycles of ddGC is an active, well-tolerated neoadjuvant regimen for the treatment of patients with MIBC. The presence of a putative deleterious DDR gene alteration in pretreatment tumor tissue strongly predicted for chemosensitivity, durable response, and superior long-term survival.

Genetic Predictors of Response to Systemic Therapy in Esophagogastric Cancer.

The incidence of esophagogastric cancer is rapidly rising, but only a minority of patients derive durable benefit from current therapies. Chemotherapy as well as anti-HER2 and PD-1 antibodies are standard treatments. To identify predictive biomarkers of drug sensitivity and mechanisms of resistance, we implemented prospective tumor sequencing of patients with metastatic esophagogastric cancer. There was no association between homologous recombination deficiency defects and response to platinum-based chemotherapy. Patients with microsatellite instability-high tumors were intrinsically resistant to chemotherapy but more likely to achieve durable responses to immunotherapy. The single Epstein-Barr virus-positive patient achieved a durable, complete response to immunotherapy. The level of ERBB2 amplification as determined by sequencing was predictive of trastuzumab benefit. Selection for a tumor subclone lacking ERBB2 amplification, deletion of ERBB2 exon 16, and comutations in the receptor tyrosine kinase, RAS, and PI3K pathways were associated with intrinsic and/or acquired trastuzumab resistance. Prospective genomic profiling can identify patients most likely to derive durable benefit to immunotherapy and trastuzumab and guide strategies to overcome drug resistance.Significance: Clinical application of multiplex sequencing can identify biomarkers of treatment response to contemporary systemic therapies in metastatic esophagogastric cancer. This large prospective analysis sheds light on the biological complexity and the dynamic nature of therapeutic resistance in metastatic esophagogastric cancers. Cancer Discov; 8(1); 49-58. ©2017 AACR.See related commentary by Sundar and Tan, p. 14See related article by Pectasides et al., p. 37This article is highlighted in the In This Issue feature, p. 1.

Immunologics and chemotherapeutics for renal cell carcinoma.

Treatment of metastatic renal cell carcinoma remains a challenge for clinicians. Traditional chemotherapy is ineffective and immunotherapy with interleukin-2 is only occasionally beneficial. The development of numerous agents targeting vascular endothelial growth factor and mammalian target of rapamycin signaling pathways that have been studied in phase III trials have resulted in significant improvement in survival for patients with clear cell renal cell carcinoma. Currently available U.S. Food and Drug Administration-approved first line targeted agents include sunitinib, pazopanib, temsirolimus, and bevacizumab (with interferon), while axitinib, everolimus, and sorafenib are most extensively used following progression as second- or third line therapy. Attempts to augment the activity of these agents by combining them together or with chemotherapy or immunotherapy have not yet proven to improve outcomes. As a result, the sequential use of single agents remains the current standard of care.

Prognostic model for predicting survival of patients with metastatic urothelial cancer treated with cisplatin-based chemotherapy.

A prognostic model that predicts overall survival (OS) for metastatic urothelial cancer (MetUC) patients treated with cisplatin-based chemotherapy was developed, validated, and compared with a commonly used Memorial Sloan-Kettering Cancer Center (MSKCC) risk-score model. Data from 7 protocols that enrolled 308 patients with MetUC were pooled. An external multi-institutional dataset was used to validate the model. The primary measurement of predictive discrimination was Harrell's c-index, computed with 95% confidence interval (CI). The final model included four pretreatment variables to predict OS: visceral metastases, albumin, performance status, and hemoglobin. The Harrell's c-index was 0.67 for the four-variable model and 0.64 for the MSKCC risk-score model, with a prediction improvement for OS (the U statistic and its standard deviation were used to calculate the two-sided P = .002). In the validation cohort, the c-indices for the four-variable and the MSKCC risk-score models were 0.63 (95% CI = 0.56 to 0.69) and 0.58 (95% CI = 0.52 to 0.65), respectively, with superiority of the four-variable model compared with the MSKCC risk-score model for OS (the U statistic and its standard deviation were used to calculate the two-sided P = .02).

Sunitinib in urothelial cancer: clinical, pharmacokinetic, and immunohistochemical study of predictors of response.

BACKGROUND: Sunitinib has activity in patients with metastatic urothelial cancer (UC), but most patients do not respond. OBJECTIVE: To identify predictors of response to sunitinib. DESIGN, SETTING, AND PARTICIPANTS: Seventy-seven patients with advanced UC received sunitinib on one of two schedules at a single institution. Blood pressure (BP), immunohistochemistry (IHC), and pharmacokinetic (PK) results were correlated with response to sunitinib. MEASUREMENTS: BP was assessed on day 1 and 28 of each cycle and on day 14 of cycle 1. IHC was performed on 55 samples from 38 cases using mammalian target of rapamycin and hypoxia-inducible factor (HIF) pathway marker antibodies. Blood samples for PK analysis were collected from 15 patients at three time points. Response was assessed using Response Evaluation Criteria in Solid Tumors criteria. RESULTS AND LIMITATIONS: Sunitinib-induced hypertension predicted improved response when hypertension was categorized as a discrete (p = 0.02) or continuous variable (p = 0.005 [systolic BP] and p = 0.007 [diastolic BP]). The odds ratio of response was 12.5 (95% confidence interval, 1.95-246.8) for grade 3/4 hypertension compared with grade 0. Response was associated with low HIF-1α expression in primary (p = 0.07) tissue. A nonstatistically significant trend was seen for an association between greater drug concentration and best response. A correlation between expression markers within the same pathways was identified, phosphorylated-4EBP1 and phosphorylated-S6 (p = 6.5 × 10(-9)), and vascular endothelial growth factor receptor 2 and HIF-1α (p = 0.008). Results are limited by small numbers. CONCLUSIONS: Clinical and molecular biomarkers of response to sunitinib may have clinical relevance and require prospective validation. There is an urgent need for predictive biomarkers to guide the management of UC.

Somatic mutation of fibroblast growth factor receptor-3 (FGFR3) defines a distinct morphological subtype of high-grade urothelial carcinoma.

FGFR3 mutations are common in low-grade urothelial carcinoma and represent a potential therapeutic target in this disease. Their incidence and functional role in high-grade urothelial carcinoma (HGUC), which displays an increased propensity for recurrence and muscularis propria invasion, is less well defined. We developed a mass spectrometry-based genotyping assay to define the incidence of FGFR3 mutations in a large clinically annotated set of urothelial carcinomas. FGFR3 mutations were found in 17% of HGUC versus 84% of low-grade lesions. Retrospective pathological review of the class of FGFR3 mutant HGUC revealed unique histological features, characterized by a bulky, exophytic component with branching papillary architecture as well as irregular nuclei with a koilocytoid appearance. The predictive value of this histological appearance was confirmed using a prospective set of 49 additional HGUCs. Prospective histological review was able to correctly predict for the presence of an FGFR3 mutation in 13/24 HGUC specimens that exhibited the distinct morphology (54%). All 25 specimens lacking the defined histological features were FGFR3 wild-type for a negative predictive value of 100%. Macrodissection of individual tumours confirmed the presence of the FGFR3 mutant allele in non-invasive and invasive, low and high-grade regions of individual tumours and in the lymph node metastases of patients whose tumours possessed the characteristic morphological signature, suggesting that FGFR3 mutations are not restricted to the more clinically indolent regions of HGUCs. These data suggest that histological screening of HGUCs followed by confirmatory genotyping can be used to enrich for the population of HGUCs most likely to harbour activating mutations in the FGFR-3 receptor tyrosine kinase. Histological review could thus aid in the development of targeted inhibitors of FGFR-3 by facilitating the identification of the subset of patients most likely to harbour activating mutations in the FGFR3 gene.

Clinical value of fluorine-18 2-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in bladder cancer.

PURPOSE: Fluorine-18 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) has been approved for imaging in many malignancies but not for bladder cancer. This study investigated the value of FDG-PET/CT imaging in the management of patients with advanced bladder cancer. PATIENTS AND METHODS: Between May 2006 and February 2008, 57 patients with bladder cancer at our center underwent FDG-PET/CT after CT (n = 52) or magnetic resonance imaging (MRI; n = 5). The accuracy of FDG-PET/CT was assessed using both organ-based and patient-based analyses. FDG-PET/CT findings were validated by either biopsy or serial CT/MRI. Clinician questionnaires performed before and after FDG-PET/CT assessed whether those scan results affected management. RESULTS: One hundred thirty-five individual lesions were evaluable in 47 patients for the organ-based analysis. Overall sensitivity and specificity were 87% (95% CI, 76% to 94%) and 88% (95% CI, 78% to 95%), respectively. In the patient-based analysis, malignant disease was correctly diagnosed in 25 of 31 patients, resulting in a sensitivity of 81% (95% CI, 63% to 93%). FDG-PET/CT was negative in 15 of 16 patients without malignant lesions for a specificity of 94% (95% CI, 71% to 100%). Pre- and post-PET surveys revealed that FDG-PET/CT detected more malignant disease than conventional CT/MRI in 40% of patients. Post-PET surveys showed that clinicians changed their planned management in 68% of patients based on the FDG-PET/CT results. CONCLUSION: FDG-PET/CT has excellent sensitivity and specificity in the detection of metastatic bladder cancer and provides additional diagnostic information that enhances clinical management more than CT/MRI alone. FDG-PET/CT scans may provide better accuracy in clinical information for directing therapy.

False elevation of human chorionic gonadotropin in a patient with testicular cancer.

BACKGROUND: A 44-year-old, HIV-positive man presented with a painless swelling of his left testicle. He underwent left radical orchiectomy for a pathological stage T1 nonseminomatous germ cell tumor (NSGCT). A persistently elevated postoperative human chorionic gonadotropin (hCG) level resulted in the patient being diagnosed as having low-risk, stage 1S disseminated NSGCT. He was treated with four cycles of etoposide and cisplatin chemotherapy, but his hCG level had not returned to normal at the end of the treatment. Postchemotherapy CT showed no evidence of metastatic disease. INVESTIGATIONS: Measurement of serum levels of tumor markers, including alpha-fetoprotein, hCG and lactate dehydrogenase, scrotal ultrasonography, HIV-1 reverse transcriptase polymerase chain reaction, CT of the thorax, abdomen and pelvis, assessment of kidney function, and measurement of follicle-stimulating hormone and luteinizing hormone levels. DIAGNOSIS: Falsely elevated serum hCG level caused by heterophile antibody interference in the hCG immunoassay. MANAGEMENT: The patient's postchemotherapy serum samples were reanalyzed using a heterophile antibody blocking agent, the results of which showed no detectable hCG. No salvage therapy was required, and the patient remains in complete remission.

Phase II study of sunitinib in patients with metastatic urothelial cancer.

PURPOSE: No standard therapy exists for metastatic urothelial cancer (UC) that has progressed after initial chemotherapy. This trial was designed to assess the efficacy and tolerability of sunitinib in patients with advanced, previously treated UC. PATIENTS AND METHODS: In this phase II trial, 77 patients received sunitinib between September 2006 and January 2009 on one of two schedules (50 mg per day for 4 weeks on and 2 weeks off [cohort A], 37.5 mg per day continuously [cohort B]), using a Simon 2 stage design in each cohort separately. RESULTS: A partial response was seen in three of 45 patients (95% CI, 1% to 18%) in cohort A, and in one of 32 patients (95% CI, 0% to 16%) in cohort B. Clinical regression or stable disease was achieved in 33 of 77 patients (43%). Tumor regression lasted between 0.6 and 23.4 months with 29% of patients achieving response lasting longer than 3 months. The progression-free survival (2.4 v 2.3 months; P = .4) and overall survival (7.1 v 6.0 months; P = .4) were similar in both cohorts. There was one treatment-related death, and 47 patients (33 cohort A, 24 cohort B) experienced grade 3 or 4 toxicity. CONCLUSION: Sunitinib did not achieve the predetermined threshold of >or= 20% activity defined by Response Evaluation Criteria in Solid Tumors. However, antitumor responses were observed, identifying the vascular endothelial growth factor axis as a viable pathway for UC treatment. The reported clinical benefit in previously treated patients warrants further investigation in a disease for which there is no US Food and Drug Administration-approved treatment.

Sequential adjuvant chemotherapy after surgical resection of high-risk urothelial carcinoma.

BACKGROUND: Despite definitive surgery, the survival of patients with high-risk urothelial carcinoma (UC) is poor. Adjuvant cisplatin-based chemotherapy may be beneficial, but it is restricted by the need for normal renal function (RF). Sequential administration of adjuvant chemotherapy facilitates drug delivery and improves survival in patients with breast cancer. The objective of this study was to evaluate the feasibility and survival impact of adjuvant, sequential chemotherapy in patients with high-risk UC. METHODS: Fifty patients were treated on 2 simultaneous protocols between 1997 and 2004. The patients on Protocol A (normal RF) received doxorubicin and gemcitabine (AG) followed by paclitaxel and cisplatin. The patients on Protocol B (impaired RF) received AG followed by paclitaxel plus carboplatin. Overall survival (OS) and disease-specific survival (DSS) were compared with a group of 203 contemporary control patients who had similar pathology and RF and who underwent surgery alone. RESULTS: The median follow-up of protocol patients was 6.5 years (range, 0.9-8.6 years), and 25 patients remained alive. The median follow-up of the control group was 4.7 years (0.0-9.2), and 68 patients remained alive. The median OS for patients on Protocol A was greater than that for controls who had good RF (4.6 years vs 2.5 years; P = .03). The median OS for patients on Protocol B was greater than that for controls who had impaired RF (3.4 years vs 2 years; P = .04). DSS for the protocol and matched control groups was similar (good RF: 4.6 years vs 3 years; P = .24; impaired RF: 3.4 years vs 3.3 years; P = .40). CONCLUSIONS: In this nonrandomized study, adjuvant, sequential chemotherapy for patients with high-risk UC did not improve DSS over that observed with surgery alone.

Final results of sequential doxorubicin plus gemcitabine and ifosfamide, paclitaxel, and cisplatin chemotherapy in patients with metastatic or locally advanced transitional cell carcinoma of the urothelium.

PURPOSE: Sequential chemotherapy with doxorubicin and gemcitabine (AG) followed by ifosfamide, paclitaxel, and cisplatin (ITP) was previously demonstrated to be well tolerated in patients with advanced transitional cell carcinoma (TCC). This study sought to evaluate the efficacy and to additionally define toxicity. PATIENTS AND METHODS: Sixty patients with advanced TCC received AG every 2 weeks for five or six cycles followed by ITP every 21 days for four cycles. Granulocyte colony-stimulating factor was given between cycles. RESULTS: Myelosuppression was seen with 68% of patients who experienced grades 3 to 4 neutropenia and with 25% who experienced febrile neutropenia. Grade 3 or greater nonhematologic toxicities were infrequent. Forty (73%) of 55 evaluable patients (95% CI, 59% to 84%) demonstrated a major response (complete, n = 19; partial, n = 21) and had a median response duration of 11.3 months (range, 1.7 to >or= 105.6 months). Twenty-seven (79%) of 34 patients with locally advanced disease (ie, T4, N0, M0) or with regional lymph node involvement (ie, T3-4, N1, M0) and 10 (56%) of 18 patients with distant metastases achieved a major response. The median progression-free survival was 12.1 months (95% CI, 9.0 to 14.8 months), and the median overall survival was 16.4 months (95% CI, 14.0 to 22.5 months). At a median follow-up of 76.4 months, seven (11.7%) patients remain alive, and all were disease free. CONCLUSION: AG plus ITP is an active regimen in previously untreated patients with advanced TCC; however, it is associated with toxicity and does not clearly offer a benefit compared with other nonsequential, cisplatin-based regimens.

Caveolin-1 is required for lateral line neuromast and notochord development.

Caveolae have been linked to diverse cellular functions and to many disease states. In this study we have used zebrafish to examine the role of caveolin-1 and caveolae during early embryonic development. During development, expression is apparent in a number of tissues including Kupffer's vesicle, tailbud, intersomite boundaries, heart, branchial arches, pronephric ducts and periderm. Particularly strong expression is observed in the sensory organs of the lateral line, the neuromasts and in the notochord where it overlaps with expression of caveolin-3. Morpholino-mediated downregulation of Cav1alpha caused a dramatic inhibition of neuromast formation. Detailed ultrastructural analysis, including electron tomography of the notochord, revealed that the central regions of the notochord has the highest density of caveolae of any embryonic tissue comparable to the highest density observed in any vertebrate tissue. In addition, Cav1alpha downregulation caused disruption of the notochord, an effect that was enhanced further by Cav3 knockdown. These results indicate an essential role for caveolin and caveolae in this vital structural and signalling component of the embryo.

Mesostructured dye-doped titanium dioxide for micro-optoelectronic applications.

Optically transparent, mesostructured titanium dioxide thin films were fabricated using an amphiphilic poly(alkylene oxide) block copolymer template in combination with retarded hydrolysis of a titanium isopropoxide precursor. Prior to calcination, the films displayed a stable hexagonal mesophase and high refractive indices (1.5 to 1.6) relative to mesostructured silica (1.43). After calcination, the hexagonal mesophase was retained with surface areas > 300 m2 g-1. The dye Rhodamine 6G (commonly used as a laser dye) was incorporated into the copolymer micelle during the templating process. In this way, novel dye-doped mesostructured titanium dioxide films were synthesised. The copolymer not only directs the film structure, but also provides a solubilizing environment suitable for sustaining a high monomer-to-aggregate ratio at elevated dye concentrations. The dye-doped films displayed optical thresholdlike behaviour characteristic of amplified spontaneous emission. Soft lithography was successfully applied to micropattern the dye-doped films. These results pave the way for the fabrication and demonstration of novel microlaser structures and other active optical structures. This new, high-refractive index, mesostructured, dye-doped material could also find applications in areas such as optical coatings, displays and integrated photonic devices.