دانلود گزارش کارورزی و کار آموزی

چکیده : 

A continuous separator based on float–sink density separation using a gas–solid fluidized bed dense medium

was used to upgrade iron ore. The separator has three devices for (A) conveying floaters, (B) recovering

floaters, and (C) conveying and recovering sinkers. The optimum speeds of these devices were

investigated using density adjusted spheres of the mm in the range of 2400–3300 kg/m3

in density increments of 100 kg/m3. A mixture of zircon sand and iron powder was used as the fluidized

medium to adjust the fluidized bed density to produce a separation kg/m3, a typical separation

density for lump iron ore wet separation. The recovery of the spheres as floaters or sinkers

depended on the speed of the devices, because the recovery was affected by the number density of

spheres directly under the feeder, the local fluidized bed density, and flow currents in the medium

derived from the movement of the devices. The optimum speeds were determined to be 3.5 cm/s for

(A), 2.0 rpm for (B) and 1.0 cm/s for (C), respectively. Continuous separation experiments were conducted

on lump iron ore particles in the size range of +11.1–31.5 mm in the fluidized bed with medium density

of 2850 kg/m3 and feed rate of 200 kg/h. Comparison of the feed rate and the recovery rate indicated that

the feed and the recovery were in equilibrium after 10 min of operation. The experiments resulted in

nearly perfect separation; 98.4% of the ore with density greater than 2850 kg/m3 was recovered. The

Fe, Al and Si content of the feed ore particles (before the separation) and the floaters and sinkers (after

the separation) was measured using inductively coupled plasma spectrometry. The separator produced

an upgrade in iron content of 3.3 wt% and reduced the Al and Si content by 44%.

چکیده : 

BACKGROUND: Endocarditis may be a marker for bacteremia-associated occult cancer. Intensive antibiotic

treatment in endocarditis is suggested to reduce long-term cancer risk. We examined these hypotheses in

a nationwide cohort study.

METHODS: Endocarditis patients and cancer cases were identified from the Danish National Registry of

Patients and the Danish Cancer Registry during 1978-2008. We compared the incidences of various

cancers among study subjects to expected incidences based on national age-, sex-, and site-specific rates.

RESULTS: We observed 997 cancers among 8445 endocarditis patients (median follow-up of 3.5 years),

reflecting an increased standardized incidence rate (SIR) of 1.61 (95% confidence interval [CI], 1.51-1.71).

Cancer risk was highly elevated during the first 3 months of follow-up (SIR8.03; 95% CI, 6.92-9.26),

partly due to a 15- to 30-fold increased risk of hematological or liver cancers. Between 3-month and 5-year

follow-ups, cancer incidence remained 1.5-fold higher than expected, including 2- and 4-fold increased

SIRs for colorectal and liver cancers, respectively. Beyond 5 years of observation, the overall cancer SIR

was 1.21 (95% CI, 1.10-1.34). Long-term associations were weak for several cancers hypothesized to be

associated with antibiotic use, including prostate, gastric, and breast cancer.

CONCLUSION: Endocarditis is a substantial clinical marker for presence of occult cancer. We found no

evidence of decreased long-term cancer risk after antibiotic treatment for endocarditis.

چکیده :

BACKGROUND: Recent studies suggest that there is an increase in cardiovascular disease after pneumonia;

however, there is little information on cardiac arrhythmias after pneumonia. The aims of this study were to

assess the incidence of, and examine risk factors for, cardiac arrhythmias after hospitalization for pneumonia.

METHODS: We conducted a national cohort study using Department of Veterans Affairs administrative data

including patients aged 65 years hospitalized with pneumonia in fiscal years 2002-2007, receiving

antibiotics within 48 hours of admission, having no prior diagnosis of a cardiac arrhythmia, and having at

least 1 year of Veterans Affairs care. We included only the first pneumonia-related hospitalization, and

follow-up was for the 90 days after admission. Cardiac arrhythmias included atrial fibrillation, ventricular

tachycardia/fibrillation, cardiac arrest, and symptomatic bradycardia. We used a multilevel regression

model, adjusting for hospital of admission, to examine risk factors for cardiac arrhythmias.

RESULTS: We identified 32,689 patients who met the inclusion criteria. Of these, 3919 (12%) had a new

diagnosis of cardiac arrhythmia within 90 days of admission. Variables significantly associated with increased

risk of cardiac arrhythmia included increasing age, history of congestive heart failure, and a need for mechanical

ventilation or vasopressors. Beta-blocker use was associated with a decreased incidence of events.

CONCLUSION: An important number of patients have new cardiac arrhythmia during and after hospitalization

for pneumonia. Additional research is needed to determine whether use of cardioprotective

medications will improve outcomes for patients hospitalized with pneumonia. At-risk patients hospitalized

with pneumonia should be monitored for cardiac arrhythmias during the hospitalization.

چکیده :

BACKGROUND: Among older persons, within the clinical context of respiratory symptoms and mobility,

evidence suggests that improvements are warranted regarding the current approach for identifying respiratory

impairment (ie, a reduction in pulmonary function).

METHODS: Among 3583 white participants aged 65 to 80 years (Cardiovascular Health Study), we

calculated the prevalence of respiratory impairment using the current spirometric standard from the Global

Initiative for Obstructive Lung Disease (GOLD) and an alternative spirometric approach termed “lambdamu-

sigma” (LMS). Results for GOLD- and LMS-defined respiratory impairment were evaluated for their

(cross-sectional) association with respiratory symptoms and gait speed, and for the 5-year cumulative

incidence probability of mobility disability.

RESULTS: The prevalence of respiratory impairment was 49.7% (1780/3583) when using the GOLD and

23.2% (831/3583) when using LMS. Differences in prevalence were most evident among participants who

had no respiratory symptoms, with respiratory impairment classified more often by the GOLD (38.1%

[326/855]) than LMS (12.3% [105/855]), as well as among participants who had normal gait speed, with

respiratory impairment classified more often by the GOLD (46.4% [1003/2164]) than LMS (19.3%

[417/2164]). Conversely, the 5-year cumulative incidence probability of mobility disability for respiratory

impairment was higher for LMS than GOLD (0.313 and 0.249 for never-smokers, and 0.352 and 0.289 for

ever-smokers, respectively), but was similar for normal spirometry by LMS or GOLD (0.193 and 0.185 for

never-smokers, and 0.219 and 0.216 for ever-smokers, respectively).

CONCLUSIONS: Among older persons, the LMS approach (vs the GOLD approach) classifies respiratory

impairment less frequently in those who are asymptomatic and is more strongly associated with mobility

disability.

چکیده : 

OBJECTIVE: To determine the impact of cognitive behavioral therapy on outcomes in primary care,

office-based buprenorphine/naloxone treatment of opioid dependence.

METHODS: We conducted a 24-week randomized clinical trial in 141 opioid-dependent patients in a

primary care clinic. Patients were randomized to physician management or physician management plus

cognitive behavioral therapy. Physician management was brief, manual guided, and medically focused;

cognitive behavioral therapy was manual guided and provided for the first 12 weeks of treatment. The

primary outcome measures were self-reported frequency of illicit opioid use and the maximum number of

consecutive weeks of abstinence from illicit opioids, as documented by urine toxicology and self-report.

RESULTS: The 2 treatments had similar effectiveness with respect to reduction in the mean self-reported

frequency of opioid use, from 5.3 days per week (95% confidence interval, 5.1-5.5) at baseline to 0.4 (95%

confidence interval, 0.1-0.6) for the second half of maintenance (P.001 for the comparisons of induction

and maintenance with baseline), with no differences between the 2 groups (P.96) or between the

treatments over time (P.44). For the maximum consecutive weeks of opioid abstinence there was a

significant main effect of time (P.001), but the interaction (P.11) and main effect of group (P.84)

were not significant. No differences were observed on the basis of treatment assignment with respect to

cocaine use or study completion.

CONCLUSIONS: Among patients receiving buprenorphine/naloxone in primary care for opioid dependence,

the effectiveness of physician management did not differ significantly from that of physician management

plus cognitive behavioral therapy.

چکیده : 

The amino-bisphosphonates are first-line therapy for the treatment of most patients with osteoporosis, with

proven efficacy to reduce fracture risk at the spine, hip, and other nonvertebral skeletal sites. Further,

bisphosphonates have been associated with a significant decrease in morbidity and increase in survival.

Following the use of bisphosphonates in millions of patients in clinical practice, some unexpected possible

adverse effects have been reported, including osteonecrosis of the jaw, atypical femur fractures, atrial fibrillation,

and esophageal cancer. Because bisphosphonates are incorporated into the skeleton and continue to exert

an antiresorptive effect for a period of time after dosing is discontinued, the concept of a drug holiday has

emerged, whereby the risk of adverse effects might be decreased while the patient still benefits from antifracture

efficacy. Patients receiving bisphosphonates who are not at high risk for fracture are potential candidates for a

drug holiday, while for those with bone mineral density in the osteoporosis range or previous history of fragility

fracture, the benefits of continuing therapy probably far outweigh the risk of harm.