Surface enhanced Raman spectroscopy and its application to molecular and cellular analysis

In this paper, we review the state-of-the-art in surface-enhanced Raman scattering (SERS) based optical detection techniques with an application focus on cancer diagnostics. As we describe herein, SERS has several analytical, biological and engineering advantages over other methods including extremely high sensitivity, inherent molecular specificity of unlabeled targets, and narrow spectral bands. We review advances in both in vitro and in vivo applications of SERS and examine how technical issues with the technology are being addressed. A special technology focus is given to emerging optofluidic devices which aim to merge microfluidic and optical detection technologies into simple packages. We conclude with a brief discussion of some of the emerging challenges in the field and some of the approaches that are likely to enhance their application. Y. S. Huh and A. J. Chung contributed equally.     

A limitation to the use of a constructive approach in the stability analysis of fixed-point digital controllers

A limitation to the application of a constructive algorithm to the stability analysis of fixed-point digital controllers is demonstrated by an example. The particular system analyzed consists of a fixed-point PI digital controller regulating a first-order process.     

Outcome of moderate carotid artery stenosis in patients who are asymptomatic

PURPOSE: The incidence rate of disease progression and stroke after the diagnosis of a moderate (50% to 79%) carotid stenosis was determined by means of color-flow duplex scanning. METHODS: During a 4-year period, 344 male veterans with moderate internal carotid artery stenoses, on one or both sides, were examined at regular intervals for a mean period of 25 months. Carotid color-flow scans were obtained semiannually. Clinical follow-up was performed to determine the incidence rate of amaurosis fugax, transient ischemic attacks, nonhemispheric symptoms, and strokes. RESULTS: New neurologic symptoms developed in 75 patients (21.8%). Fifty-one (14.8%) had ipsilateral symptoms during follow-up: 18 amaurosis fugax (5.2%), 14 transient ischemic attacks (4%), 5 nonhemispheric symptoms (1.4%), and 14 strokes (4%). Twenty-four patients (6.9%) had contralateral symptoms: 20 strokes (5.8%) and 4 transient ischemic attacks (1.2%). Life-table analysis showed that the annual rate of ipsilateral neurologic events was 8.1%, and the annual rate of stroke was 2.1%. Seventy-five patients (22%) died in the follow-up period. Disease progression to 80% to 99% stenosis or occlusion occurred in 71 of 458 vessels (15.5%). The internal carotid arteries that showed evidence of disease progression had a significantly higher initial peak systolic velocity (251 vs 190 cm/s; P <.0001) and end diastolic velocity (74 vs 52 cm/s; P < 0.0001). Black patients and patients with ischemic heart disease were at a higher risk for disease progression. We could not identify any atherosclerotic risk factors that reliably predicted patients in whom future ipsilateral neurologic symptoms were more likely to develop. However, there was an increased risk of stroke associated with progression of disease. CONCLUSION: Patients who are asymptomatic and who have moderate carotid stenoses are at significant risk for neurologic symptoms and death, but have a relatively low incidence rate of ipsilateral events. The initial flow characteristics in the stenotic vessel are predictive of future disease progression, but they are not helpful in identifying patients in whom symptoms will develop.     

Barley distillers grains as a protein supplement for dairy cows

Dried distillers grains produced from a mix of 65% barley and 35% corn were evaluated in digestion and lactation experiments. Dried barley distillers grains had 56% NDF, 29% CP, 3% amino acid N, 2.5% NDIN (55% of total N), and 1.8% ADIN (39% of total N). Wet barley distillers grains had 38% NDF, 27% CP, 2.7% amino acid N, .5% NDIN (12% of total N), and .8% ADIN (19% of total N). Digestibility of DM and N was similar among lactating dairy cows fed diets containing approximately 25% corn silage DM, 15% alfalfa silage DM, 15% alfalfa hay DM, plus varying amounts of a corn-barley concentrate mix and supplemental CP from soybean meal, barley distillers grains, or from 1:1 mixture of soybean meal and barley distillers grains. Digestibility of ADIN, NDF, and ADF increased with increasing amounts of barley distillers grains in the diet. Similar diets were fed to 60 Holstein cows for 84 d in a lactation experiment. Source of supplemental protein did not affect milk production (22.5 kg/d), FCM (20.4 kg/d), milk fat percent (3.6%), or DM intake (19.0 kg/d). Milk protein percent was decreased by feeding barley distillers grains. It was concluded that barley distillers grains were an acceptable protein source for dairy cows and that ADIN and NDF might not be appropriate measures of the nutritional value of this product.     

Patterns of psoriatic arthritis in Orientals

OBJECTIVE: To determine the clinical features of psoriatic arthritis (PsA) in a multiethnic Oriental population and to study the effect of ethnicity on disease patterns. METHODS: A retrospective study of 80 patients with PsA seen at either a rheumatology or dermatology referral center. Patients and case records were reviewed and data abstracted according to a standard protocol. Eighty consecutive patients with psoriasis without PsA seen at the dermatology center were recruited as controls. RESULTS: Asymmetric polyarthritis developing in the 4th decade with an equal male to female ratio was the commonest pattern of arthritis among Chinese, Indians, and Malays. Clinically apparent lumbar spondylitis was significantly more common in Indians than Chinese (10/11 vs 11/20, respectively; p = 0.046), although the prevalence of lumbar spondylitis was similar in all ethnic groups. Eighty-nine percent of subjects required nonsteroidal antiinflammatory drugs and 51% required disease modifying antirheumatic drugs at some time for control of joint disease. PsA was significantly more common among Indians compared to the ethnic distribution of the Singapore population (p < 0.000001). Multiple logistic regression identified Indian ethnicity as a risk factor for the development of PsA (OR 2.39, 95% confidence interval 1.02 to 5.60). CONCLUSION: The commonest pattern of PsA in all ethnic groups was asymmetric polyarthritis. Ethnicity affected the development and presentation of PsA in our series: Indians with psoriasis had double the risk of developing PsA compared to Chinese with psoriasis, and lumbar spondylitis when present in Chinese subjects was asymptomatic in 45%, being detectable only on radiological examination.     

Electric Heating of Pipelines with Variable Resistance Wire

The electrical heating of pipelines has received a lot of attention recently because of better controllability and maintenance experience than steam tracing. This paper describes a way of electrical heating with a variable resistance wire. The installation in a manufacturing area, with many zones of process piping to be heated is described. These methods reduced design and installation costs.