Low Correlation Interference OFDM-NLFM Waveform Design for MIMO Radar Based on Alternating Optimization.

The OFDM chirp signal is suitable for MIMO radar applications due to its large time-bandwidth product, constant time-domain, and almost constant frequency-domain modulus. Particularly, by introducing the time-frequency structure of the non-linear frequency modulation (NLFM) signal into the design of an OFDM chirp waveform, a new OFDM-NLFM waveform with low peak auto-correlation sidelobe ratio (PASR) and peak cross-correlation ratio (PCCR) is obtained. IN-OFDM is the OFDM-NLFM waveform set currently with the lowest PASR and PCCR. Here we construct the optimization model of the OFDM-NLFM waveform set with the objective function being the maximum of the PASR and PCCR. Further, this paper proposes an OFDM-NLFM waveform set design algorithm inspired by alternating optimization. We implement the proposed algorithm by the alternate execution of two sub-algorithms. First, we keep both the sub-chirp sequence code matrix and sub-chirp rate plus and minus (PM) code matrix unchanged and use the particle swarm optimization (PSO) algorithm to obtain the optimal parameters of the NLFM signal's time-frequency structure (NLFM parameters). Next, we keep current optimal NLFM parameters unchanged, and optimize the sub-chirp sequence code matrix and sub-chirp rate PM code matrix using the block coordinate descent (BCD) algorithm. The above two sub-algorithms are alternately executed until the objective function converges to the optimal solution. The results show that the PASR and PCCR of the obtained OFDM-NLFM waveform set are about 5 dB lower than that of the IN-OFDM.

Imaging of reactive oxygen species burst from mitochondria using laser scanning confocal microscopy.

OBJECTIVE: Although several methods have been used to detect the intracellular reactive oxygen species (ROS) generation, it is still difficult to determine where ROS generate from. This study aimed to demonstrate whether ROS generate from mitochondria during oxidative stress induced mitochondria damage in cardiac H9c2 cells by laser scanning confocal microscopy (LSCM). METHODS: Cardiac H9c2 cells were exposed to H2 O2 (1200µM) to induce mitochondrial oxidant damage. Mitochondrial membrane potential (ΔΨm) was measured by staining cells with tetramethylrhodamine ethyl ester (TMRE); ROS generation was measured by staining cells with dichlorodihydrofluorescein diacetate (H2 DCFDA). RESULTS: A rapid/transient ROS burst from mitochondria was induced in cardiac cells treated with H2 O2 compared with the control group, suggesting that mitochondria are the main source of ROS induced by oxidative stress in H9c2 cells. Meanwhile, the TMRE fluorescence intensity of mitochondria which had produced a great deal of ROS decreased significantly, indicating that the burst of ROS induces the loss of ΔΨm. In addition, the structure of mitochondria was damaged seriously after ROS burst. However, we also demonstrated that the TMRE fluorescence intensity might be affected by H2 DCFDA. CONCLUSIONS: Mitochondria are the main source of ROS induced by oxidative stress in H9c2 cells and these findings provide a new method to observe whether ROS generate from mitochondria by LSCM. However, these observations also suggested that it is inaccurate to test the fluorescence intensities of cells stained with two or more different fluorescent dyes which should be paid more attention to.

In a non-diabetic Japanese population, the combination of macroalbuminuria and increased urine beta 2-microglobulin predicts a decline of renal function: the Takahata study.

BACKGROUND: Glomerular and tubular damage are important factors in the development of renal insufficiency. However, the interaction of these factors is largely unknown in the non-diabetic Japanese population. To clarify the relationship between renal insufficiency and both glomerular and tubular damage, we conducted a community-based study using albuminuria and urine beta 2-microglobulin as markers of glomerular and tubular damages, respectively. METHODS: Subjects of this study were 2816 non-diabetic individuals >40 years old in Takahata, Japan. The urine albumin-creatinine ratio (UACR) and urine beta 2-microglobulin-creatinine ratio (UBCR) were assessed from single spot urine. The glomerular filtration rate (eGFR) was estimated using the abbreviated MDRD equation with a Japanese coefficient. RESULTS: The prevalence of albuminuria (UACR >20 mg/ g in men and >30 mg/g in women), increased UBCR (>300 microg/g) and renal insufficiency (eGFR <60 mL/ min/1.73 m(2)) were 21.0%, 12.5% and 21.7%, respectively, and there was only a small overlap between the three. The mean eGFR was significantly lower in subjects with macroalbuminuria (UACR >200 mg/g in men and >300 mg/g in women) and increased UBCR. No urinary abnormalities were observed in 71.7% of the 611 subjects with renal insufficiency, and were more common in young, women and the non-hypertensive population. The 1-year decline of eGFR was greatest in subjects with an overlap of macroalbuminuria and increased UBCR. CONCLUSIONS: This study indicated that only a small part of renal insufficiency accompanied increased urine albumin or beta 2-microglobulin in the non-diabetic Japanese population. The combination of macroalbuminuria and increased urine beta 2-microglobulin might predict faster renal deterioration.

Factors correlated with plasma renin activity in general Japanese population.

BACKGROUND: The renin-angiotensin-aldosterone system plays a pivotal role in regulation of blood pressure and electrolyte homeostasis and is a target in the treatment of hypertension and renal diseases. However, the factors correlated with plasma renin activity (PRA) are unclarified in general Japanese population. To examine this point, we conducted a community-based cross-sectional study. METHODS: Subjects of this study were 2,056 individuals (mean age, 61 years; 934 men; 1,122 women) over 40-year-old without antihypertensive medication in Takahata town, Japan. PRA was measured by radioimmunoassay. Estimated 24-h urine sodium (e24hUNa) and potassium excretion were calculated from morning spot urine. RESULTS: The median value of PRA was higher in men compared to women (1.1 ng/ml/h vs. 0.7 ng/ml/h, P < 0.001). The increased PRA (>2.0 ng/ml/h) were detected in 248 men (26.3%) and 142 women (12.7%). One-factor analysis of variance showed that PRA was correlated with blood pressure, uric acid, hemoglobin, total protein, total cholesterol, low-density lipoprotein cholesterol, serum adiponectin and e24hUNa in men. In women, PRA was correlated with age, blood pressure, total protein, high-density lipoprotein cholesterol (HDL-C), serum insulin, e24hUNa and obesity. Multivariate logistic regression analysis showed that high PRA (>2.0 ng/ml/h) was independently associated with low blood pressures, low e24UNa and high serum total protein both in men and women, smoking only in men and high HDL-C only in women, respectively. CONCLUSIONS: This study revealed that PRA was higher in men than women and was associated negatively with blood pressures and urine sodium excretion, and positively with total protein, smoking and HDL-C in Japanese population.

Relationship between antinuclear antibody and microalbuminuria in the general population: the Takahata study.

BACKGROUND: Microalbuminuria, a marker of vascular damage, is associated with increased risk of progressive renal deterioration, cardiovascular disease and mortality. However, the relationship between antinuclear antibody (ANA) and microalbuminuria in the general population is unknown. Thus, we conducted a cross-sectional study to examine the relationship between ANA and microalbuminuria. METHODS: The subjects of this community-based study were individuals over 40 years old in Takahata, Japan. The urine albumin-creatinine ratio (UACR) was calculated from a single-spot urine specimen collected in the morning. ANA was examined by enzyme immunoassay (EIA). RESULTS: Among the 2,875 subjects (mean age 63 years; men 1,276; women 1,599), positive ANA (ANA index >or=20.0) was detected in 16.9% of the total population (men 12.9%, women 20.3%) and the prevalence of positive ANA increased with age. The prevalence of microalbuminuria (UACR 30-300 mg/g), but not macroalbuminuria (UACR > 300 mg/g), was significantly higher in the positive ANA group than the negative ANA group (24.1% vs. 16.0%, respectively, P < 0.001). Along with the increase of the ANA index, the prevalence of microalbuminuria and UACR levels were increased. Multivariate logistic regression analyses showed that ANA was significantly associated with microalbuminuria (odds ratio [OR] 1.63 and 95% confidence interval [95%CI] 1.27-2.10). These associations were significant in women, but not men, when examined separately. CONCLUSIONS: These results indicate that the presence of ANA is associated with microalbuminuria in the general population, especially women.

The association between microalbuminuria and metabolic syndrome in the general population in Japan: the Takahata study.

OBJECTIVE: The metabolic syndrome is associated with an increased risk of chronic kidney disease, cardiovascular disease and mortality. However, the association between microalbuminuria and the metabolic syndrome has not yet been reported in the general population in Japan. Therefore, we undertook a population-based study to examine the association between microalbuminuria and the metabolic syndrome in Takahata, Japan. METHODS: Subjects of this cross-sectional study were individuals aged from 40 to 87 years old. The metabolic syndrome was defined according to the criteria of the Adult Treatment Panel III. Microalbuminuria was defined as a urine albumin-creatinine ratio of 30 to 300 mg/g. RESULTS: A total of 2,321 subjects (mean age 64 years old) were entered into the final analysis. Among them, the prevalence of the metabolic syndrome and microalbuminuria was 16.5% and 13.7%, respectively. There was a significantly positive correlation between the number of components of the metabolic syndrome and the corresponding prevalence of microalbuminuria (p<0.001). In the subjects with metabolic syndrome compared with those without metabolic syndrome, the age- and gender-adjusted odds ratio of microalbuminuria was 1.99 (95% CI, 1.49-2.66). Multiple logistic regression analysis revealed that high glucose, high blood pressure and obesity were independently associated with microalbuminuria. CONCLUSIONS: Our study revealed a strong relationship between microalbuminuria and the metabolic syndrome in the general population in Japan. More comprehensive and intensive management of the metabolic syndrome at its early stage is important to prevent the progression of renal injury and cardiovascular complications.

Clinical utility of trace proteinuria for microalbuminuria screening in the general population.

BACKGROUND: The urine dipstick test that regards > 1+ proteinuria as positive is unsuitable for microalbuminuria screening owing to its low sensitivity in the general population. We conducted a cross-sectional survey to examine whether trace proteinuria could be an indicator of microalbuminuria. METHODS: The subjects were 2321 participants in a community-based health check-up in Takahata, Japan. Dipstick tests for proteinuria and the urine albumin-creatinine ratio (UACR) measurement were performed with single-spot urine specimens collected early in the morning. The results of the dipstick tests were recorded as (-), trace, (1+), (2+), and (3+). Micro- and macroalbuminuria were defined as UACR 30-300 mg/g and > 300 mg/g, respectively. RESULTS: Overall, the prevalence and median UACR levels of urine protein (-), trace, (1+), (2+), and (3+) were 92.0% (8.8 mg/g), 3.5% (43 mg/g), 2.6% (81 mg/g), 1.4% (315 mg/g), and 0.5% (1073 mg/g), respectively. Within the trace proteinuria category, the prevalence of microalbuminuria in all subjects, men, subjects >or=60 years, diabetic subjects, and hypertensive subjects was 59.3%, 73.8%, 71.2%, 88.9%, and 68.0%, respectively. By regarding trace proteinuria as positive, the sensitivity of the urine protein dipstick test for micro- and macroalbuminuria was improved (from 23.3% to 37.1%), while its specificity was not significantly changed (from 98.9% to 97.3%). CONCLUSION: Trace proteinuria could be a useful indicator of microalbuminuria in the general population, and especially in subjects at high risk of cardiovascular disease.