The benefit of liver transplant beyond Milan criteria: An analysis using the National Cancer Database

BACKGROUND

Published studies examining the efficacy of liver transplantation in patients presenting with hepatocellular cancer beyond the traditional Milan criteria for liver transplantation have primarily been single institution series with limited ability to compare outcomes to alternative methods of management.

METHODS

We queried the National Cancer Database to identify patients presenting between 2004 and 2016 with histologically confirmed clinical stage III and IVA hepatocellular cancer. Multivariable regression was used to identify factors associated with liver transplantation. Patients undergoing liver transplantation were 1:1 propensity score-matched for age, demographics, comorbid disease, clinical stage, and histologic resection margin to those undergoing surgical resection. The Kaplan-Meier method was used to compare overall survival profiles for matched cohorts.

RESULTS

Seven hundred and ninety-two patients met inclusion criteria-590 (74.5%) underwent surgical resection and 202 (25.5%) liver transplantation. On adjusted analysis, patients undergoing liver transplantation were less likely to have advanced age (>60 years; odds ratio 0.39, 95% confidence interval [0.21-0.71]) and to be of Black race (odds ratio 0.42, 95% confidence interval [0.23-0.73]) or Asian (odds ratio 0.25, 95% confidence interval [0.11-0.53]) ethnicity but were more likely to have advanced (Charlson score >2) comorbidity scores, (odds ratio 2.48, 95% confidence interval [1.58-3.90]) and more likely to have private health insurance (odds ratio 4.17, 95% confidence interval [1.31-18.66]) than those undergoing surgical resection. On Kaplan-Meier analysis of matched cohorts, patients undergoing liver transplantation demonstrated significantly better rates of 5-year overall survival (65.3% vs 26.3%, P < .0001) and longer median overall survival times than those undergoing resection (53.1 ± 2.78 vs 26.9 ± 1.20 months, P < .0001).

CONCLUSION

Liver transplantation offers the potential to be an effective treatment modality in select patients presenting with stage III and IVA hepatocellular cancer.

Combined Use of Aspirin and Statin is Associated With a Decreased Incidence of Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a leading cause of cancer and cancer-related mortality worldwide. Studies have suggested that aspirin (ASA) and statins may be associated with a decrease in incident HCC.

GOALS

We aimed to evaluate the effect of ASA and statin use on the incidence of HCC in a prospective cohort of patients with liver cirrhosis and to identify if there was an increased risk of esophageal variceal hemorrhage (VH) in patients with ASA use.

STUDY

We conducted a retrospective study of 521 patients with data collected from July 1, 2012 to December 31, 2017. We used competing risk analysis to assess the association between risk factors and HCC; and the association between ASA and VH.

RESULTS

ASA use alone was associated with a decreased incidence of HCC in the univariate and multivariate models; [hazard ratio (HR) confidence interval (CI): 0.348 (0.124-0.976); P=0.0448] and [HR (CI): 0.266 (0.094-0.755); P=0.0129, respectively]. The combination of ASA and statin use was associated with a decreased hazard of HCC [HR (CI): 0.15 (0.036-0.624); P=0.0090] and this remained statistically significant in the multivariable model [HR (CI): 0.113 (0.026-0.483); P=0.0033]. Among daily ASA users compared with non-users, there was not a significant increase in risk of VH.

CONCLUSIONS

Daily ASA use was associated with a decrease risk of incident HCC. The combination of daily ASA use and statin use decreased the risk of incident HCC suggesting there is beneficial interaction. Finally, no excess VH was observed in daily ASA users compared with non-users.

Urinary tract infections in cystic fibrosis patients

Improved understanding of non-respiratory infections in cystic fibrosis (CF) patients will be vital to sustaining the increased life span of these patients. To date, there has not been a published report of urinary tract infections (UTIs) in CF patients. We performed a retrospective chart review at a major academic medical center during 2010-2020 to determine the features of UTIs in 826 CF patients. We identified 108 UTI episodes during this period. Diabetes, distal intestinal obstruction syndrome (DIOS), and nephrolithiasis were correlated with increased risk of UTIs. UTIs in CF patients were less likely to be caused by Gram-negative rods compared to non-CF patients and more likely to be caused by Enterococcus faecalis. The unique features of UTIs in CF patients highlight the importance of investigating non-respiratory infections to ensure appropriate treatment.

Publisher Correction: SLX4 interacts with RTEL1 to prevent transcription-mediated DNA replication perturbations

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Provider Attitudes and Practice Patterns for Direct-Acting Antiviral Therapy for Patients With Hepatocellular Carcinoma

BACKGROUND & AIMS

Direct-acting antivirals (DAAs) are effective against hepatitis C virus and sustained virologic response is associated with reduced incidence of hepatocellular carcinoma (HCC). However, there is controversy over the use of DAAs in patients with active or treated HCC and uncertainty about optimal management of these patients. We aimed to characterize attitudes and practice patterns of hepatology practitioners in the United States regarding the use of DAAs in patients with HCC.

METHODS

We conducted a survey of hepatology providers at 47 tertiary care centers in 25 states. Surveys were sent to 476 providers and we received 279 responses (58.6%).

RESULTS

Provider beliefs about risk of HCC recurrence after DAA therapy varied: 48% responded that DAAs reduce risk, 36% responded that DAAs do not change risk, and 16% responded that DAAs increase risk of HCC recurrence. However, most providers believed DAAs to be beneficial to and reduce mortality of patients with complete response to HCC treatment. Accordingly, nearly all providers (94.9%) reported recommending DAA therapy to patients with early-stage HCC who received curative treatment. However, fewer providers recommended DAA therapy for patients with intermediate (72.9%) or advanced (57.5%) HCC undergoing palliative therapies. Timing of DAA initiation varied among providers based on HCC treatment modality: 49.1% of providers reported they would initiate DAA therapy within 3 months of surgical resection whereas 45.9% and 5.0% would delay DAA initiation for 3-12 months and >1 year post-surgery, respectively. For patients undergoing transarterial chemoembolization (TACE), 42.0% of providers would provide DAAs within 3 months of the procedure, 46.7% would delay DAAs until 3-12 months afterward, and 11.3% would delay DAAs more than 1 year after TACE.

CONCLUSIONS

Based on a survey sent to hepatology providers, there is variation in provider attitudes and practice patterns regarding use and timing of DAAs for patients with HCC. Further studies are needed to characterize the risks and benefits of DAA therapy in this patient population.

Direct-Acting Antiviral Therapy for Hepatitis C Virus Infection Is Associated With Increased Survival in Patients With a History of Hepatocellular Carcinoma

BACKGROUND & AIMS

There is controversy regarding the benefits of direct-acting antiviral (DAA) therapy for hepatitis C virus (HCV) infection for patients with a history of hepatocellular carcinoma (HCC). We performed a multicenter cohort study to compare overall survival between patients with HCV infection treated with DAAs and patients who did not receive DAA treatment for their HCV infection after complete response to prior HCC therapy.

METHODS

We conducted a retrospective cohort study of patients with HCV-related HCC who achieved a complete response to resection, local ablation, transarterial chemo- or radioembolization, or radiation therapy, from January 2013 through December 2017 at 31 health care systems throughout the United States and Canada. We used Cox proportional hazards regression to determine the association between receipt of DAA therapy, modeled as a time-varying covariate, and all-cause mortality, accounting for informative censoring and confounding using inverse probability weighting.

RESULTS

Of 797 patients with HCV-related HCC, 383 (48.1%) received DAA therapy and 414 (51.9%) did not receive treatment for their HCV infection after complete response to prior HCC therapy. Among DAA-treated patients, 43 deaths occurred during 941 person-years of follow-up, compared with 103 deaths during 526.6 person-years of follow-up among patients who did not receive DAA therapy (crude rate ratio, 0.23; 95% confidence interval [CI], 0.16-0.33). In inverse probability-weighted analyses, DAA therapy was associated with a significant reduction in risk of death (hazard ratio, 0.54; 95% CI, 0.33-0.90). This association differed by sustained virologic response to DAA therapy; risk of death was reduced in patients with sustained virologic response to DAA therapy (hazard ratio, 0.29; 95% CI, 0.18-0.47), but not in patients without a sustained virologic response (hazard ratio, 1.13; 95% CI, 0.55-2.33).

CONCLUSIONS

In an analysis of nearly 800 patients with complete response to HCC treatment, DAA therapy was associated with a significant reduction in risk of death.

Direct-Acting Antiviral Therapy Not Associated With Recurrence of Hepatocellular Carcinoma in a Multicenter North American Cohort Study

BACKGROUND & AIMS

There is controversy over the effects of direct-acting antiviral (DAA) therapies for hepatitis C virus (HCV) infection on hepatocellular carcinoma (HCC) recurrence and tumor aggressiveness. We compared HCC recurrence patterns between DAA-treated and untreated HCV-infected patients who had achieved a complete response to HCC treatment in a North American cohort.

METHODS

We conducted a retrospective cohort study of patients with HCV-related HCC with a complete response to resection, local ablation, transarterial chemo- or radioembolization, or radiation therapy from January 2013 through December 2017 at 31 health systems throughout the United States and Canada. Cox regression was used to examine the association between DAA therapy and time to recurrence after a complete response, with DAA therapy analyzed as a time-varying exposure. We also estimated the association between DAA therapy and risk of early HCC recurrence (defined as 365 days after complete response).

RESULTS

Of 793 patients with HCV-associated HCC, 304 (38.3%) received DAA therapy and 489 (61.7%) were untreated. HCC recurred in 128 DAA-treated patients (42.1%; early recurrence in 52 patients) and 288 untreated patients (58.9%; early recurrence in 227 patients). DAA therapy was not associated with HCC recurrence (hazard ratio 0.90, 95% confidence interval 0.70-1.16) or early HCC recurrence (hazard ratio 0.96, 95% confidence interval 0.70-1.34) after we adjusted for study site, age, sex, Child-Pugh score, α-fetoprotein level, tumor burden, and HCC treatment modality. In DAA-treated and untreated patients, most recurrences were within the Milan criteria (74.2% vs 78.8%; P = .23). A larger proportion of DAA-treated than untreated patients received potentially curative HCC therapy for recurrent HCC (32.0% vs 24.6%) and achieved a complete or partial response (45.3% vs 41.0%) but this did not achieve statistical significance.

CONCLUSION

In a large cohort of North American patients with complete response to HCC treatment, DAA therapy was not associated with increased overall or early HCC recurrence. HCC recurrence patterns, including treatment response, were similar in DAA-treated and untreated patients.

Risk factors and outcomes of acute respiratory distress syndrome in critically ill patients with cirrhosis

AIM

Prior randomized controlled trials of acute respiratory distress syndrome (ARDS) excluded critically ill patients with cirrhosis. Data regarding risk factors for ARDS development and outcomes from ARDS in patients with cirrhosis are scarce. We sought to characterize outcomes from ARDS in patients with cirrhosis.

METHODS

An observational cohort of patients with cirrhosis admitted to an intensive care unit at a high-volume liver transplant center between 1 January 2012 and 31 December 2014 were reviewed. ARDS cases were identified according to the Berlin definition. Potential risk factors were examined in multivariable logistic regression analysis for ARDS development. Outcomes including in-hospital mortality were compared between ARDS and non-ARDS patients.

RESULTS

A total of 559 patients met the inclusion criteria and 45 (8.1%) developed ARDS. Differences between ARDS and non-ARDS patients included sepsis, Model for End-Stage Liver Disease - Sodium score, and Sequential Organ Failure Assessment score. In-hospital mortality was higher in cirrhotic patients with ARDS compared with those without ARDS (82.2% vs. 27.6%, P < 0.001). In multivariable analysis, acute-on-chronic liver failure (OR 8.69, 95% CI 2.28-33.18, P < 0.01) and shock on intensive care unit admission (OR 3.13, 95% CI 1.57-6.24, P = 0.001) were associated with ARDS development, whereas etiology of cirrhosis or alcohol use were not.

CONCLUSIONS

Acute-on-chronic liver failure and shock on intensive care unit admission were risk factors for ARDS development, whereas etiology of cirrhosis and alcohol were not. Mortality from ARDS was markedly increased in patients with cirrhosis. Early recognition and treatment for infection might be important for improving the high mortality in this group of patients.

Topographical Features of Graphene-Oxide-Functionalized Substrates Modulate Cancer and Healthy Cell Adhesion Based on the Cell Tissue of Origin

Graphene-derived materials, such as graphene oxide (GO), have been widely explored for biomedical and biological applications, including cancer research. Despite some recent works proving that GO inhibits the migration and invasion of different cancer cells, so far most of these in vitro studies have been conducted using GO sheets dispersed in solution or as a planar film. On the contrary, little is known about cellular activities, such as cell viability, adhesion, and spreading, when cancer cells interface with GO functionalized hydrogel-based surfaces, biomechanically and structurally more similar to the tumor environment. Here, we evaluate the interactions of human breast cancer cells (MDA-MB-231) with alginate (Alg)/GO hydrogel-based substrates, and compare them with a cancer cell line from human osteosarcoma (HOS) and healthy murine fibroblasts (3T3). We observed that GO addition selectively inhibits malignant breast cancer cell adhesion efficiency and spreading area, while promotes HOS and 3T3 adhesive processes. Furthermore, we did not observe the same results over Alg substrates with GO nanosheets dispersed in the medium, without embedment into the Alg. This suggests that cancer (MDA-MB-231 and HOS) and healthy (3T3) cell adhesion efficacy does not depend on the cellular tumoral nature and it is driven by the topographical cues provided by the GO-based substrates, whose physical-mechanical characteristics better mimic those of the cell native tissue. We envision that this study can provide a rational for future design and use of graphene-based nanomaterials for cancer research by deepening the knowledge of graphene-cancer cell specific interactions.

Photon momentum change of quasi-smooth solar sails

The solar photon sail (SPS) allows space missions without propellant that would otherwise not be feasible. Thrust models frequently used in the literature for the calculation of trajectories often underestimate the effect that the surface roughness has on SPS dynamics. A small variation of the thrust vector can induce a large modification of sail flight. In this work, the variation of the photon momentum vector (PMV) is computed as resulting from the incident Sun radiation, taking into account the absorbed and reflected photons. The momentum resulting from diffuse light has been modeled by using vectorial scattering theories in the limit of a quasi-smooth sail where the first-order of Rayleigh-Rice can be applied. In particular, the momentum change resulting from diffuse radiation causes a PMV reduction as well as a deviation of its direction from what is foreseen in the case of an ideally smooth sail.

The role of hepatitis E virus infection in adult Americans with acute liver failure

Acute hepatitis E virus (HEV) infection is a leading cause of acute liver failure (ALF) in many developing countries, yet rarely identified in Western countries. Given that antibody testing for HEV infection is not routinely obtained, we hypothesized that HEV-related ALF might be present and unrecognized in North American ALF patients. Serum samples of 681 adults enrolled in the U.S. Acute Liver Failure Study Group were tested for anti-HEV immunoglobulin (Ig) M and anti-HEV IgG levels. Subjects with a detectable anti-HEV IgM also underwent testing for HEV RNA. Mean patient age was 41.8 years, 32.9% were male, and ALF etiologies included acetaminophen (APAP) hepatotoxicity (29%), indeterminate ALF (23%), idiosyncratic drug-induced liver injury DILI (22%), acute hepatitis B virus infection (12%), autoimmune hepatitis (12%), and pregnancy-related ALF (2%). Three men ages 36, 39, and 70 demonstrated repeatedly detectable anti-HEV IgM, but all were HEV-RNA negative and had other putative diagnoses. The latter 2 subjects died within 3 and 11 days of enrollment whereas the 36-year-old underwent emergency liver transplantation on study day 2. At admission, 294 (43.4%) of the ALF patients were anti-HEV IgG positive with the seroprevalence being highest in those from the Midwest (50%) and lowest in those from the Southeast (28%). Anti-HEV IgG⁺ subjects were significantly older, less likely to have APAP overdose, and had a lower overall 3-week survival compared to anti-HEV IgG^- subjects (63% vs. 70%; P = 0.018).

CONCLUSION

Acute HEV infection is very rare in adult Americans with ALF (i.e., 0.4%) and could not be implicated in any indeterminate, autoimmune, or pregnancy-related ALF cases. Past exposure to HEV with detectable anti-HEV IgG was significantly more common in the ALF patients compared to the general U.S.

POPULATION

(Hepatology 2016;64:1870-1880).

A Synthesis of Hepatitis C prevalence estimates in Sub-Saharan Africa: 2000-2013

Background

Hepatitis C (HCV) is a deleterious virus that can be cured with new, highly effective anti-viral treatments, yet more than 185 million individuals worldwide remain HCV positive (with the vast majority un-diagnosed or untreated). Of importance, HCV is a leading cause of chronic liver disease and liver cancer, especially in Sub-Saharan Africa (SSA) where the prevalence remains high but uncertain due to little population-based evidence of the epidemic. We aimed to synthesize available data to calculate and highlight the HCV disease burden in SSA.

Methods

Weighted random-effects generalized linear mixed models were used to estimate prevalence by risk cohort, African region (Southern, Eastern, Western, and Central Africa), type of assay used, publication year, and whether the estimate included children. A pooled prevalence estimate was also calculated. Multi-variable analyses were limited to cohort and region specific prevalence estimates in the adult population due to limited studies including children. Prevalence estimates were additionally weighted using the known adult population size within each region.

Results

We included more than 10 years of data. Almost half of the studies on HCV prevalence in SSA were from the Western region (49 %), and over half of all studies were from either blood donor (25 %) or general population cohorts (31 %). In uni-variable analyses, prevalence was lowest in Southern Africa (0.72 %), followed by Eastern Africa at 3.00 %, Western Africa at 4.14 %, and Central Africa at 7.82 %. Blood donors consistently had the lowest prevalence (1.78 %), followed by pregnant women (2.51 %), individuals with comorbid HIV (3.57 %), individuals from the general population (5.41 %), those with a chronic illness (7.99 %), and those at high risk for infection (10.18 %). After adjusting for the population size in each region, the overall adult prevalence of HCV in SSA rose from 3.82 to 3.94 %.

Conclusion

This meta-analysis offers a timely update to the HCV disease burden in SSA and offers additional evidence of the burgeoning epidemic. The study highlights the need to account for type of cohort and region variation when describing the HCV epidemic in SSA, the need for more studies that include children, as well as the need to factor in such variations when planning public health interventions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1584-1) contains supplementary material, which is available to authorized users.

Regulatory influence of scaffolds on cell behavior: how cells decode biomaterials

A stem cell is defined as a cell able to self-renew and at the same time to generate one or more specialized progenies. In the adult organism, stem cells need a specific microenvironment where to reside. This tissue-specific instructive microenvironment, hosting stem cells and governing their fate, is composed of extracellular matrix and soluble molecules. Cell-matrix and cell-cell interactions also contribute to the specifications of this milieu, regarded as a whole unitary system and referred to as "niche". For many stem cell systems a niche has been identified, but only partially defined. In regenerative medicine and tissue engineering, biomaterials are used to deliver stem cells in specific anatomical sites where a regenerative process is needed. In this context, biomaterials have to provide informative microenvironments mimicking a physiological niche. Stem cells may read and decode any biomaterial and modify their behavior and fate accordingly. Any material is therefore informative in the sense that its intrinsic nature and structure will anyway transmit a signal that will have to be decoded by colonizing cells. We still know very little of how to create local microenvironments, or artificial niches, that will govern stem cells behavior and their terminal fate. Here we will review some characteristics identifying specific niches and some of the requirements allowing stem cells differentiation processes. We will discuss on those biomaterials that are being projected/engineered/manufactured to gain the informative status necessary to drive proper molecular cross-talk and cell differentiation; specific examples will be proposed for bone and cartilage substitutes.

Network integration of data and analysis of oncology interest

The Human Genome Project has deeply transformed biology and the field has since then expanded to the management, processing, analysis and visualization of large quantities of data from genomics, proteomics, medicinal chemistry and drug screening. This huge amount of data and the heterogeneity of software tools that are used implies the adoption on a very large scale of new, flexible tools that can enable researchers to integrate data and analysis on the network. ICT technology standards and tools, like Web Services and related languages, and workflow management systems, can support the creation and deployment of such systems. While a number of Web Services are appearing and personal workflow management systems are also being more and more offered to researchers, a reference portal enabling the vast majority of unskilled researchers to take profit from these new technologies is still lacking. In this paper, we introduce the rationale for the creation of such a portal and present the architecture and some preliminary results for the development of a portal for the enactment of workflows of interest in oncology.

Engineering of osteoinductive grafts by isolation and expansion of ovine bone marrow stromal cells directly on 3D ceramic scaffolds

In this work, we investigated whether osteoinductive constructs can be generated by isolation and expansion of sheep bone marrow stromal cells (BMSC) directly within three-dimensional (3D) ceramic scaffolds, bypassing the typical phase of monolayer (2D) expansion prior to scaffold loading. Nucleated cells from sheep bone marrow aspirate were seeded into 3D ceramic scaffolds either by static loading or under perfusion flow and maintained in culture for up to 14 days. The resulting constructs were exposed to enzymatic treatment to assess the number and lineage of extracted cells, or implanted subcutaneously in nude mice to test their capacity to induce bone formation. As a control, BMSC expanded in monolayer for 14 days were also seeded into the scaffolds and implanted. BMSC could be isolated and expanded directly in the 3D ceramic scaffolds, although they proliferated slower than in 2D. Upon ectopic implantation, the resulting constructs formed a higher amount of bone tissue than constructs loaded with the same number of 2D-expanded cells. Constructs cultivated for 14 days generated significantly more bone tissue than those cultured for 3 days. No differences in bone formation were found between samples seeded by static loading or under perfusion. In conclusion, the culture of bone marrow nucleated cells directly on 3D ceramic scaffolds represents a promising approach to expand BMSC and streamline the engineering of osteoinductive grafts.

Improvement in volume estimation from confocal sections after image deconvolution

The confocal microscope can image a specimen in its natural environment forming a 3D image of the whole structure by scanning it and collecting light through a small aperture (pinhole), allowing in vivo and in vitro observations. So far, the confocal fluorescence microscope (CFM) is considered a true volume imager because of the role of the pinhole that rejects information coming from out-of-focus planes. Unfortunately, intrinsic imaging properties of the optical scheme presently employed yield a corrupted image that can hamper quantitative analysis of successive image planes. By a post-image collection restoration, it is possible to obtain an estimate, with respect to a given optimization criterium, of the true object, utilizing the impulse response of system or Point Spread Function (PSF). The PSF can be measured or predicted so as to have a mathematical and physical model of the image-formation process. Further modelling and recording noise as an additive Gaussian process has used the regularized Iterative Constrained Tykhonov Miller (ICTM) restoration algorithm for solving the inverse problem. This algorithm finds the best estimate iteratively searching among the possible positive solutions; in the Fourier domain, such an approach is relatively fast and elegant. In order to compare the effective improvement in the quantitative image information analysis, we measured the volume of reference objects before and after image restoration, using the isotropic Fakir method.

Interfacial effect of extremely low frequency electromagnetic fields (EM-ELF) on the vaporization step of carbon dioxide from aqueous solutions of body simulated fluid (SBF)

Spontaneous processes in an aqueous solution of body simulated fluid (SBF) were monitored in closed vessel for a period of 1 month at 310 K, at atm pressure, and initial pH of 7.2, both with and without exposure to a square pulsed extremely low frequency electromagnetic fields (EM-ELF) of 250 microT, repeated at 75 Hz. The most important findings are that the SBF surface tension (gamma), evaluated under the EM-ELF field, is lower than the corresponding value measured without EM-ELF at any time. Furthermore, the pH of the exposed SBF is always more basic than that of the unexposed solution. As a consequence, when the EM-ELF is applied, calcium phosphate salts do not precipitate from the SBF solution for a period as long as 30 days. Behind all these experimental evidences there is only one mechanism: the vaporisation from the SBF-air interface of the CO(2)(aq) dissolved into the aqueous electrolyte solution. Thermodynamic analysis of these results establish that, at any given time, the difference, Delta, between the measured surface tensions with and without EM-ELF applied, gives the work of the electromagnetic forces to change the extent at which the CO(2)(aq) adsorbs at the liquid-air interface. It has been demonstrated that the work supply per second and per unit of area by the electromagnetic forces, 3.73 x 10(-10) mJ/s cm(2), is very near to the experimental slope in the plot Delta vs. t 1.7 x 10(-10) mJ/s cm(2). This leads to the conclusion that the EM-ELF fields have an interfacial effect on the concentration value of the CO(2) (aq) at the SBF-air interface. Because of that, the EM-ELF field is enhancing the CO(2) vaporisation rate; thus any other steps, which are a consequence of this mechanism, are changing. These results allow explanation of previous experiments concerning the precipitation of calcium carbonate from flowing hydrogen carbonate aqueous solution in the temperature range 353-373 K at a pressure of 0.1 MPa under the effect of static magnetic fields.

Phase shift of stepwise reflectivity profile mirrors

The effects of phase shifts in laser beams transmitted by output couplers with a stepwise reflectivity profile have been experimentally investigated with a XeCl laser. It is shown that the phase distortions of the cavity output coupler affect significantly the propagation properties of the output laser beam but do not affect the output beam energy and pulse width.