3,181 research outputs found
A CMOS Digital Beamforming Receiver
As the demand for high speed communication is increasing, emerging wireless techniques seek to utilize unoccupied frequency ranges, such as the mm-wave range. Due to high path loss for higher carrier frequencies, beamforming is an essential technology for mm-wave communication. Compared to analog beamforming, digital beamforming provides multiple simultaneous beams without an SNR penalty, is more accurate, enables faster steering, and provides full access to each element. Despite these advantages, digital beamforming has been limited by high power consumption, large die area, and the need for large numbers of analog-to-digital converters. Furthermore, beam squinting errors and ADC non-linearity limit the use of large digital beamforming arrays. We address these limitations.
First, we address the power and area challenge by combining Interleaved Bit Stream Processing (IL-BSP) with power and area efficient Continuous-Time Band-Pass Delta-Sigma Modulators (CTBPDSMs). Compared to conventional DSP, IL-BSP reduces both power and area by 80%. Furthermore, the new CTBPDSM architecture reduces ADC area by 67% and the energy per conversion by 43% compared to previous work.
Second, we introduce the first integrated digital true-time-delay digital beamforming receiver to resolve the beam squinting. True-time-delay beamforming eliminates squinting, making it an ideal choice for large-array wide-bandwidth applications.
Third, we present a new current-steering DAC architecture that provides a constant output impedance to improve ADC linearity. This significantly reduces distortion, leading to an SFDR improvement of 13.7 dB from the array.
Finally, we provide analysis to show that the ADC power consumption of a digital beamformer is comparable to that of the ADC power for an analog beamformer.
To summarize, we present a prototype phased array and a prototype timed array, both with 16 elements, 4 independent beams, a 1 GHz center frequency, and a 100 MHz bandwidth. Both the phased array and timed array achieve nearly ideal conventional and adaptive beam patterns, including beam tapering and adaptive nulling. With an 11.2 dB array gain, the phased array achieves a 58.5 dB SNDR over a 100 MHz bandwidth, while consuming 312 mW and occupying 0.22 mm2. The timed array achieves an EVM better than -37 dB for 5 MBd QAM-256 and QAM-512, occupies only 0.29 mm2, and consumes 453 mW.PHDElectrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/147716/1/smjang_1.pd
Effects and treatment methods of acupuncture and herbal medicine for premenstrual syndrome/premenstrual dysphoric disorder: systematic review
BACKGROUND: During their reproductive years about 10% of women experience some kind of symptoms before menstruation (PMS) in a degree that affects their quality of life (QOL). Acupuncture and herbal medicine has been a recent favorable therapeutic approach. Thus we aimed to review the effects of acupuncture and herbal medicine in the past decade as a preceding research in order to further investigate the most effective Korean Medicine treatment for PMS/PMDD. METHODS: A systematic literature search was conducted using electronic databases on studies published between 2002 and 2012. Our review included randomized controlled clinical trials (RCTs) of acupuncture and herbal medicine for PMS/PMDD. Interventions include acupuncture or herbal medicine. Clinical information including statistical tests was extracted from the articles and summarized in tabular form or in the text. Study outcomes were presented as the rate of improvement (%) and/or end-of-treatment scores. RESULTS: The search yielded 19 studies. In screening the RCTs, 8 studies in acupuncture and 11 studies in herbal medicine that matched the criteria were identified. Different acupuncture techniques including traditional acupuncture, hand acupuncture and moxibustion, and traditional acupuncture technique with auricular points, have been selected for analysis. In herbal medicine, studies on Vitex Agnus castus, Hypericum perforatum, Xiao yao san, Elsholtzia splendens, Cirsium japonicum, and Gingko biloba L. were identified. Experimental groups with Acupuncture and herbal medicine treatment (all herbal medicine except Cirsium japonicum) had significantly improved results regarding PMS/PMDD. CONCLUSIONS: Limited evidence supports the efficacy of alternative medicinal interventions such as acupuncture and herbal medicine in controlling premenstrual syndrome and premenstrual dysphoric disorder. Acupuncture and herbal medicine treatments for premenstrual syndrome and premenstrual dysphoric disorder showed a 50% or better reduction of symptoms compared to the initial state. In both acupuncture and herbal medical interventions, there have been no serious adverse events reported, proving the safety of the interventions while most of the interventions provided over 50% relief of symptoms associated with PMS/PMDD. Stricter diagnostic criteria may have excluded many participants from some studies. Also, depending on the severity of symptoms, the rate of improvement in the outcomes of the studies may have greatly differed
Broussonetia papyrifera Root Bark Extract Exhibits Anti-inflammatory Effects on Adipose Tissue and Improves Insulin Sensitivity Potentially Via AMPK Activation
The chronic low-grade inflammation in adipose tissue plays a causal role in obesity-induced insulin resistance and its associated pathophysiological consequences. In this study, we investigated the effects of extracts of Broussonetia papyrifera root bark (PRE) and its bioactive components on inflammation and insulin sensitivity. PRE inhibited TNF-alpha-induced NF-kappa B transcriptional activity in the NF-kappa B luciferase assay and pro-inflammatory genes' expression by blocking phosphorylation of I kappa B and NF-kappa B in 3T3-L1 adipocytes, which were mediated by activating AMPK. Ten-week-high fat diet (HFD)-fed C57BL6 male mice treated with PRE had improved glucose intolerance and decreased inflammation in adipose tissue, as indicated by reductions in NF-kappa B phosphorylation and pro-inflammatory genes' expression. Furthermore, PRE activated AMP-activated protein kinase (AMPK) and reduced lipogenic genes' expression in both adipose tissue and liver. Finally, we identified broussoflavonol B (BF) and kazinol J (KJ) as bioactive constituents to suppress pro-inflammatory responses via activating AMPK in 3T3-L1 adipocytes. Taken together, these results indicate the therapeutic potential of PRE, especially BF or KJ, in metabolic diseases such as obesity and type 2 diabetes
PPM1A Controls Diabetic Gene Programming through Directly Dephosphorylating PPAR?? at Ser273
Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a master regulator of adipose tissue biology. In obesity, phosphorylation of PPAR gamma at Ser273 (pSer273) by cyclin-dependent kinase 5 (CDK5)/extracellular signal-regulated kinase (ERK) orchestrates diabetic gene reprogramming via dysregulation of specific gene expression. Although many recent studies have focused on the development of non-classical agonist drugs that inhibit the phosphorylation of PPAR gamma at Ser273, the molecular mechanism of PPAR gamma dephosphorylation at Ser273 is not well characterized. Here, we report that protein phosphatase Mg2+/Mn2+-dependent 1A (PPM1A) is a novel PPAR gamma phosphatase that directly dephosphorylates Ser273 and restores diabetic gene expression which is dysregulated by pSer273. The expression of PPM1A significantly decreases in two models of insulin resistance: diet-induced obese (DIO) mice and db/db mice, in which it negatively correlates with pSer273. Transcriptomic analysis using microarray and genotype-tissue expression (GTEx) data in humans shows positive correlations between PPM1A and most of the genes that are dysregulated by pSer273. These findings suggest that PPM1A dephosphorylates PPAR gamma at Ser273 and represents a potential target for the treatment of obesity-linked metabolic disorders
Optimal application of compressive palatal stents following mesiodens removal in pediatric patients:a Randomized Controlled Trial
There is no scientific evidence supporting the choice of a palatal stent in patients who underwent removal of an impacted supernumerary tooth. We aimed to investigate the effects of palatal stents in patients who underwent supernumerary tooth removal through a palatal approach and to suggest the optimal stent thickness and material. We recruited 144 patients who underwent extraction of a supernumerary tooth between the maxillary anterior teeth. Subjects were assigned to a control group (CG) or one of four compressive palatal stent groups (CPSGs) classified by the thickness and material of the thermoplastic acrylic stent used. Palatal gingival swelling and objective indices (healing, oral hygiene, gingival, and plaque) were evaluated before surgery and on postoperative days (PODs) 3, 7, and 14; pain/discomfort and the Child Oral Health Impact Profile (COHIP) were assessed as subjective indices of the effects of the stent. The CPSGs showed faster healing than did the CG on PODs 7 (P<0.001) and 14 (P=0.043); swelling was measured by 1.64Ā±0.88 mm and 4.52Ā±0.39 mm, respectively. Although swelling was least in the 4-mm hard group (0.92Ā±0.33 mm), the difference compared with that in the 2-mm hard group (1.01Ā±0.18 mm) was not significant (P=0.077). The CPSGs showed better COHIP (P<0.001-0.036) and pain scores (P<0.001) than did the CG on PODs 1-3. Compressive palatal stents reduce discomfort by decreasing pain and alleviating swelling. Although a stent is effective regardless of its thickness and material, 2-mm hard stents maximized such positive effects with minimal discomfort
Far-Ultraviolet Cooling Features of the Antlia Supernova Remnant
We present far-ultraviolet observations of the Antlia supernova remnant
obtained with Far-ultraviolet IMaging Spectrograph (FIMS, also called SPEAR).
The strongest lines observed are C IV 1548,1551 and C III 977. The C IV
emission of this mixed-morphology supernova remnant shows a clumpy
distribution, and the line intensity is nearly constant with radius. The C III
977 line, though too weak to be mapped over the whole remnant, is shown to vary
radially. The line intensity peaks at about half the radius, and drops at the
edge of the remnant. Both the clumpy distribution of C IV and the rise in the C
IV to C III ratio towards the edge suggest that central emission is from
evaporating cloudlets rather than thermal conduction in a more uniform, dense
medium.Comment: 9 pages, 4 figures, will be published in ApJ December 1, 2007, v670n2
issue. see http://astro.snu.ac.kr/~jhshinn/ms.pd
Sasa borealis Stem Extract Attenuates Hepatic Steatosis in High-Fat Diet-induced Obese Rats
The aim of the current study is to examine the improving effect of Sasa borealis stem (SBS) extract extracts on high-fat diet (HFD)-induced hepatic steatosis in rats. To determine the hepatoprotective effect of SBS, we fed rats a normal regular diet (ND), HFD, and HFD supplemented with 150 mg/kg body weight (BW) SBS extracts for five weeks. We found that the body weight and liver weight of rats in the HFD + SBS group were significantly lower than those in the HFD group. Significantly lower serum total cholesterol (TC) and triglyceride (TG) concentrations were observed in the SBS-supplemented group compared with the HFD group. We also found that the HFD supplemented with SBS group showed dramatically reduced hepatic lipid accumulation compared to the HFD alone group, and administration of SBS resulted in dramatic suppression of TG, TC in the HFD-induced fatty liver. In liver gene expression within the SBS treated group, PPARĪ± was significantly increased and SREBP-1c was significantly suppressed. SBS induced a significant decrease in the hepatic mRNA levels of PPARĪ³, FAS, ACC1, and DGAT2. In conclusion, SBS improved cholesterol metabolism, decreased lipogenesis, and increased lipid oxidation in HFD-induced hepatic steatosis in rats, implying a potential application in treatment of non-alcoholic fatty liver disease
Characterisation of Pseudomonas aeruginosa related to bovine mastitis
Pseudomonas aeruginosa is one of the causative pathogens of bovine mastitis. Most P. aeruginosa strains possess the type III secretion system (TTSS), which may increase somatic cell counts (SCCs) in milk from mastitis-affected cows. Moreover, most of P. aeruginosa cells can form biofilms, thereby reducing antibiotic efficacy. In this study, the presence and effect of TTSS-related genotypes on increase of SCCs among 122 P. aeruginosa isolates obtained from raw milk samples from mastitis-affected cows and their antibiotic susceptibility at planktonic and biofilm status were investigated. Based on the presence of TTSS-related genes a total of 82.7% of the isolates were found to harbour exoU and/or exoS genes, including the invasive (exoU-/exoS+, 69.4%), cytotoxic (exoU+/exoS-, 8.3%) and cytotoxic/invasive strains (exoU+/ exoS+, 5.0%). Milk containing exoS-positive isolates had higher SCCs than those containing exoS-negative isolates. The majority of isolates showed gentamicin, amikacin, meropenem and ciprofloxacin susceptibility at planktonic status. However, the susceptibility was decreased at the biofilm status. Based on minimum biofilm eradication concentration (MBEC)/minimum inhibitory concentration (MIC) ratios, the range of change in antibiotic susceptibility varied widely depending on the antibiotics (from ā„ 3.1-fold to ā„ 475.0-fold). In conclusion, most P. aeruginosa isolates studied here had a genotype related to increase in SCCs. The efficiency of antibiotic therapy against P. aeruginosa-related bovine mastitis could be improved by analysing both the MBEC and the MIC of isolates
Fully automatic integration of dental CBCT images and full-arch intraoral impressions with stitching error correction via individual tooth segmentation and identification
We present a fully automated method of integrating intraoral scan (IOS) and
dental cone-beam computerized tomography (CBCT) images into one image by
complementing each image's weaknesses. Dental CBCT alone may not be able to
delineate precise details of the tooth surface due to limited image resolution
and various CBCT artifacts, including metal-induced artifacts. IOS is very
accurate for the scanning of narrow areas, but it produces cumulative stitching
errors during full-arch scanning. The proposed method is intended not only to
compensate the low-quality of CBCT-derived tooth surfaces with IOS, but also to
correct the cumulative stitching errors of IOS across the entire dental arch.
Moreover, the integration provide both gingival structure of IOS and tooth
roots of CBCT in one image. The proposed fully automated method consists of
four parts; (i) individual tooth segmentation and identification module for IOS
data (TSIM-IOS); (ii) individual tooth segmentation and identification module
for CBCT data (TSIM-CBCT); (iii) global-to-local tooth registration between IOS
and CBCT; and (iv) stitching error correction of full-arch IOS. The
experimental results show that the proposed method achieved landmark and
surface distance errors of 112.4 m and 301.7 m, respectively
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