Robust concatenated codes for the slow Rayleigh fading channel

In this thesis, we design a robust concatenated code for the Multiple-Input Multiple-Output (MIMO) system in the presence of slow Rayleigh fading with no channel side information at the transmitter (no CSIT) and perfect channel side information at the receiver (perfect CSIR). Since we are interested in the slow fading channel, outage capacity is used as the measure of performance. Good space-time codes can be designed so as to maximize the so-called rank and the determinant criteria. However, a practical system will concatenate a space-time code with an outer code at the transmitter and perform iterative decoding at the receiver. It is necessary to design the space-time code together with the outer code in practice. We will call this kind of code a concatenated space-time code. At the transmitter, we will consider the bit-to-symbol mapping and space-time code together as a space-time modulator and thus, Bit Interleaved Coded Modulation (BICM) and Multilevel coding (ML) can be applied to design outer codes for the nonbinary constellation. However, the concatenated space-time codes designed by these two methods can only be decoded with arbitrarily small error probability for a fixed channel realization and such designs are not robust over the ensemble of fading channels. Our approach of designing concatenated space-time code is to design an outer code for a space-time modulator such that the concatenated space-time code can be decoded with arbitrarily small error probability in a set of fixed channels which have the same capacity. Through this approach, we discovered a new design criterion for spacetime codes: a good space-time code should stabilize its Extrinsic Information Transfer (EXIT) charts. In other words, the robustness of a space-time code in the slow fading channel and its performance in iterative decoding can be visualized by the EXIT charts. The rank and the determinant criterion do not evaluate the performance of a space-time code in iterative decoding, but the new criterion does. Therefore, the new criterion is applicable to design concatenated space-time codes. Applying our approach and new criterion, a rate 7.2 bits/s/Hz concatenated space-time code is designed. The performance is close to the outage capacity, and the rate lost is 0.2 bits/s/Hz

Using nomogram of the Barcelona Clinic Liver Cancer system for treatment selection in patients with stage C hepatocellular carcinoma

Abstract Background The nomogram of the Barcelona Clinic Liver Cancer (BCLC) for hepatocellular carcinoma (HCC) has been used for outcome prediction. Patients with BCLC stage C HCC often undergo anti-cancer therapy against current treatment guidelines in real world practice. We aimed to use the nomogram to provide guidance on treatment selection for BCLC stage C patients. Methods A total of 1317 patients with stage C HCC were retrospectively analyzed and divided into four groups by nomogram points. One-to-one matched pairs between patients receiving different treatments were generated by the propensity score with matching model within these groups. Survival analysis was performed by Kaplan-Meier method with log-rank test. Results Patients with higher nomogram points were more often treated with targeted or supportive therapies (p  15, there was no significant difference in survival between patients receiving two different treatment strategies. Conclusions The nomogram of BCLC system is a feasible tool to help stage C HCC patients to select primary anti-cancer treatment in pursuance of better overall survival.https://deepblue.lib.umich.edu/bitstream/2027.42/142787/1/12885_2018_Article_4202.pd

Assessing liver dysfunction in cirrhosis: Role of the model for end-stage liver disease and its derived systems

The model for end-stage liver disease (MELD) has replaced the role of the Child–Turcotte–Pugh system as a more commonly used system in evaluating the severity of liver dysfunction in patients with chronic liver disease, owing to its superior ability to predict survival. The United Network of Organ Sharing (UNOS) in the USA has used the MELD system for prioritizing donor grafts in advanced cirrhotic patients awaiting liver transplantation since 2002. Serum sodium level is another important prognostic predictor in cirrhosis. Consequently, by incorporating serum sodium into the original MELD, the MELD-Na, MELDNa, the MELD-to-sodium ratio (MESO) index, and the ReFit MELDNa were proposed in an attempt to improve the predictive ability of the original MELD. Nevertheless, there are some limitations of the MELD-based systems that need to be refined. The MELD-based systems merely use laboratory data as parameters for the equation, therefore, any lack in unification and standardization of laboratory methods will result in inconsistent data that affect the prioritization of liver transplantation. Furthermore, the MELD system includes creatinine as a parameter, and serum creatinine level may represent different degrees of renal dysfunction in men and women. Therefore, these limitations may compromise the fair process of organ allocation for female cirrhotic patients. Currently, the application of the MELD system has been extended to tumor staging of hepatocellular carcinoma. Several studies have replaced the Child–Turcotte–Pugh system with the MELD as a parameter, indicating that the use of different criteria of liver dysfunction in cancer staging may enhance prognostic accuracy. Although the outcome data of the modified staging systems need to be confirmed, the concept of using the MELD as a reference system for evaluating the severity of liver dysfunction has globally become an important issue

The association of macronutrients in human milk with the growth of preterm infants.

BackgroundBreast milk is the optimal choice for feeding premature babies. However, the prevalence rate of extrauterine growth restriction in preterm infants remains high.ObjectivesThe purpose of this study was to analyze the macronutrients present in human milk and the correlation with the growth of in-hospital preterm infants.MethodsThis prospective study is based on data from 99 in-hospital preterm infants younger than 37 weeks of gestational age on an exclusively human milk diet. Infants who had previously received parenteral nutrition were eligible, but they had to have reached full enteral feeding at the time that the samples were taken. A total of 3282 samples of raw human milk or donor pasteurized milk were collected. The levels of lactose, protein, fat, and energy in the samples were measured using a Miris human milk analyzer. The primary outcome was weight growth velocity (g/kg/day) which was obtained using two-point approach.ResultsThe mean (±standard deviation) macronutrient composition per 100 mL of milk was 7.2 (±0.3) g of lactose, 1.1 (±0.2) g of true protein, 3.5 (±0.9) g of fat, and 66.9 (±6.5) kcal of energy. The protein concentration in human milk had a positive, significant correlation with body weight gain, with a coefficient of 0.41 (p ConclusionBoth the protein concentration in human milk and the daily total protein intake had a positive correlation with the body weight gain of premature infants. Routine analysis of breast milk and individualized fortification might be indicated to optimize the growth of preterm infants

Hepatocellular Carcinoma Patients With Performance Status 1 Deserve New Classification and Treatment Algorithm in the BCLC System

Hepatocellular carcinoma (HCC) patients with performance status (PS) 1 or 2 are considered similar in the Barcelona Clinic Liver Cancer (BCLC) system. The rationales are not fully studied. A total of 693 and 335 HCC patients were classified as PS 1 and 2, respectively, in a prospectively followed up database. One-to-one matched pairs between HCC patients were generated by using the propensity score with matching model. Survival analysis was performed and the hazard ratio was calculated with the Cox proportional hazards model. Patients with PS 1 were significantly younger and had better liver and renal functions compared with patients with PS 2 (all P 0.05); patients with PS 1 had significantly better prognosis compared with patients with PS 2 (P < 0.05). There were 68% of patients with PS 1 that underwent aggressive treatments (resection, transplantation, percutaneous ablation, or transarterial chemoembolization), which were significantly correlated to better outcome with a hazard ratio of 0.539 in the matching model (P = 0.002). For patients with PS 2, aggressive treatments were not significantly associated with better long-term survival. Aggressive treatments provide survival benefits for patients with PS 1, but not for patients with PS 2. HCC patients with PS 1 or 2 should be considered clinically different disease entities in the BCLC system

When to Perform Surgical Resection or Radiofrequency Ablation for Early Hepatocellular Carcinoma? A Nomogram-guided Treatment Strategy

Radiofrequency ablation (RFA) is indicated for early-stage hepatocellular carcinoma (HCC), but the comparative efficacy between RFA and surgical resection (SR) is inconclusive. We aim to develop a prognostic nomogram for predicting recurrence-free survival (RFS) after RFA. We also evaluate the possibility of using nomogram in improving treatment algorithm.We retrospectively enrolled 836 patients with Barcelona Clinic Liver Cancer very-early/early-stage HCC receiving SR or RFA. A visually-orientated nomogram was constructed with Cox proportional hazards model, and number and size of tumor, platelet count, albumin level, and model for end-stage liver disease score were included. The concordance index of the nomogram was 0.69.Radiofrequency ablation patients were stratified into low and high-risk groups by the median of nomogram scores. The RFS and overall survival (OS) of 2 risk groups were compared with SR patients with propensity score matching analysis. SR provided better RFS and OS compared with high-risk (nomogram score 9.8) RFA patients in the propensity model. The 5-year RFS rates were 36% versus 11%, whereas the 5-year OS rates were 74% versus 60% for SR and high-risk RFA groups, respectively (both P0.05, respectively).In conclusion, this user-friendly nomogram offers individualized recurrence risk estimation and stratification for early HCC patients receiving curative RFA. The nomogram can be integrated into current treatment algorithm. SR should be considered the first-line treatment for high-risk patients to achieve better long-term survival

Hong Kong Liver Cancer Staging System Is Associated With Better Performance for Hepatocellular Carcinoma Special Emphasis on Viral Etiology

Hong Kong Liver Cancer (HKLC) staging system was developed for prognostic and treatment evaluation for hepatocellular carcinoma (HCC) but is not externally validated. We aimed to evaluate and compare HKLC system with Barcelona Clinic Liver Cancer (BCLC) staging system. The prognostic performance, discriminatory ability, and efficacy of treatment recommendations were compared between the BCLC and HKLC systems. Significant differences in survival were found across all stages of BCLC and across stages I to IV of HKLC systems (P<0.01). HKLC system was associated with higher homogeneity in prognostic accuracy. The survival was similar between patients treated according to the HKLC or BCLC system (P=0.07). However, more patients were treated according to HKLC recommendations than to BCLC recommendations (57% vs. 47%, P<0.001). In a hypothetical cohort created by random sampling, patients treated according to the HKLC scheme had better survival compared with patients treated according to the BCLC system (P<0.001).Subgroup analyses between hepatitis B virus (HBV) and hepatitis C virus (HCV)-related HCC were performed. More HCV-related HCC were at earlier BCLC or HKLC stages (both P<0.001). The HKLC system was more informative with greater homogeneity in predicting survival in both HBV and HCV cohorts. However, HKLC treatment recommendations were associated with better long-term survival only in HBV-related HCC but not in HCV-related HCC (P<0.001 and P=0.79, respectively).In conclusion, we provided external validation of the HKLC system. Compared with the BCLC system, the HKLC system has better prognostic accuracy and therapeutic efficacy in the entire cohort and in HBV-related HCC but not in HCV-related HCC. Due to high heterogeneity among patients of various etiologies, staging and treatment strategies tailored to specific HCC etiology are required

Prognostic impact of diabetes mellitus on hepatocellular carcinoma: Special emphasis from the BCLC perspective.

BACKGROUND:Diabetes mellitus (DM) is associated with higher incidence and poorer prognosis of hepatocellular carcinoma (HCC). The influence of DM on patient survival in different HCC stages is not known. METHODS:A prospective dataset of 3,182 HCC patients was collected between 2002 and 2014. Patients were divided into three groups according to BCLC stages (BCLC stage 0 and stage A, BCLC stage B, BCLC stage C and stage D). We compared the cumulative survival rate of diabetic and non-diabetic patients in different BCLC groups. The correlation between DM and overall survival was also analyzed by multivariate Cox regression model within each group. RESULTS:DM is present in 25.2% of all patients. Diabetic patients had lower cumulative survival in BCLC stage 0 plus BCLC stage A group (log rank p<0.001), and BCLC stage B group (log rank p = 0.012), but not in BCLC stage C plus BCLC stage D group (log rank p = 0.132). Statistically significant differences in overall survival are found between diabetic and non-diabetic patients in BCLC stage 0 plus stage A group (adjusted hazard ratio [HR] = 1.45, 95% confidence interval [CI] 1.08-1.93, p = 0.013), and BCLC stage B (adjusted HR = 1.77, 95% CI 1.24-2.51, p = 0.002). In contrast, the survival difference is not seen in BCLC stage C plus stage D group (adjusted HR = 1.09, 95% CI 0.90-1.30, p = 0.387). CONCLUSIONS:DM is prevalent in HCC, and is associated with lower survival rate in HCC patients with BCLC stage 0 plus stage A and B, but not in those with BCLC stage C plus stage D

A New Treatment-integrated Prognostic Nomogram of the Barcelona Clinic Liver Cancer System for Hepatocellular Carcinoma

The nomogram of the Barcelona Clinic Liver Cancer (BCLC) has accurate outcome prediction. This study aims to propose a treatment-integrated nomogram derived from BCLC for patients with hepatocellular carcinoma (HCC). A total of 3,371 patients were randomly grouped into derivation (n = 2,247) and validation (n = 1,124) sets. Multivariate Cox proportional hazards model was used to generate the nomogram from tumor burden, cirrhosis, performance status (PS) and primary anti-cancer treatments. Concordance indices and calibration plots were used to evaluate the performance of nomogram. The derivation and validation sets had the same concordance index of 0.774 (95% confidence intervals: 0.717-0.826 and 0.656-0.874, respectively). In calibration plots, survival distributions predicted by the nomogram and observed by the Kaplan-Meier method were similar at 3- and 5-year for patients from derivation and validation sets. Validation group patients divided into 10 subgroups by the original and new treatment-integrated BCLC nomogram were used to evaluate the prognostic performance of integrating primary anti-cancer treatments. Compared to the nomogram of original BCLC system, the treatment-integrated nomogram of BCLC system had larger linear trend and likelihood ratio X-2. In conclusion, based on the results of concordance index tests, integrating primary anti-cancer treatments into the BCLC system provides similar discriminatory ability