Application of Laguerre based adaptive predictive control to Shape Memory Alloy (SMA) Actuator

This paper discusses the use of an existing adaptive predictive controller to control some Shape Memory Alloy (SMA) linear actuators. The model consists in a truncated linear combination of Laguerre filters identified online. The controller stability is studied in details. It is proven that the tracking error is asymptotically stable under some conditions on the modelling error. Moreover, the tracking error converge toward zero for step references, even if the identified model is inaccurate. Experimental results obtained on two different kind of actuator validate the proposed control. They also show that it is robust with regard to input constraints.

pH-responsive drug delivery of chitosan nanoparticles as Tamoxifen carriers for effective anti-tumor activity in breast cancer cells

Tamoxifen (Tam) has a broad spectrum of anticancer activity, but is limited in clinical application. The aim of this study was to explore the smart pH-responsive drug delivery system (DDS) based on chitosan (CH) nanoparticles (NPs) for its potential in enabling more intelligent controlled release and enhancing chemotherapeutic efficiency of Tamoxifen. Tamoxifen was loaded onto CH-nanoparticles by forming complexes and Tamoxifen was released from the DDS much more rapidly at pH 4.0 and 6.0 than at pH 7.4, which is a desirable characteristic for tumor-targeted drug delivery. Tamoxifen-loaded CH nanoparticles induced remarkable improvement in anticancer activity, as demonstrated by MTT-assay, AO/EtBr and Hoechst nuclear staining. Furthermore, the possible signaling pathway was explored by RT-PCR. For instance, in human breast cancer MCF-7 cells, it was demonstrated that Tamoxifen-loaded CH nanoparticles increase intracellular concentration of Tamoxifen and enhance its anticancer efficiency by inducing apoptosis in a caspase-dependent manner, indicating that drug loaded nanoparticles could act as an efficient DDS importing Tamoxifen into target cancer cells.

Prevalence of opportunistic intestinal parasitic infection among HIV infected patients who are taking antiretroviral treatment at Jimma Health Center, Jimma, Ethiopia

BACKGROUND

One of the major health problems among HIV sero-positive patients are superimposed infections due to the deficient immunity. Furthermore, intestinal parasitic (IP) infections, which are also one of the basic health problems in tropical regions, are common in these patients. Infection by opportunistic pathogens, including various forms of intestinal parasites has been the hall mark of HIV since the beginning of the epidemic.

AIM

To study the prevalence of opportunistic intestinal parasitic infection among HIV patients who are taking antiretroviral treatment (ART) in Jimma, Ethiopia.

MATERIALS AND METHODS

Patient samples were diagnosed by examination of single stool specimen which was examined as fresh wet mounts, formal-ether concentration technique and modified Ziehl-Neelsen staining technique. Data was obtained from 91 study subjects selected by convenience sampling method.

RESULTS

The overall prevalence of intestinal parasitic infections was found to be 39.56%. Eight types of intestinal parasites was identified, the most dominant being, Ascaris lumbricoides, 21.67%, Entamoeba histolytica, 15% and Cryptosporidium parvum 13.33%. The prevalence of opportunistic parasite was 15.38%, the prevalence of non-opportunistic parasite was 20.87% and the prevalence of both opportunistic and non opportunistic was 3.29%.

CONCLUSIONS

The study indicated that intestinal parasites were still a problem in the study area. Data also showed that among the predisposing factors, habit of hand washing before meal, usage of latrine and duration after treatment was statistically associated with intestinal parasitic infections.

Tuberculosis masquerading as oral malignancy

Tuberculosis of the oral cavity is a rare condition. A 55-year-old labourer was referred as a case of oral cancer for further management. The patient had no systemic symptoms. Biopsy of the lesion revealed caseating granulomatous inflammation. Chest X-ray and sputum revealed evidence of asymptomatic pulmonary tuberculosis. The purpose of this paper is to sensitize clinicians to consider oral tuberculosis as a differential diagnosis in patients with an Non-healing oral cavity ulcer.

Update on bacterial nosocomial infections

With increasing use of antimicrobial agents and advance in lifesaving medical practices which expose the patients for invasive procedures, are associated with the ever increasing of nosocomial infections. Despite an effort in hospital infection control measures, health care associated infections are associated with significant morbidity and mortality adding additional health care expenditure which may leads to an economic crisis. The problem is further complicated with the emergence of difficult to treat multidrug resistant (MDR) microorganism in the hospital environment. Virtually every pathogen has the potential to cause infection in hospitalized patients but only limited number of both gram positive and gram negative bacteria are responsible for the majority of nosocomial infection. Among them Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Enterococci takes the leading. Many intrinsic and extrinsic factors predispose hospitalized patients for these pathogens. Following simple hospital hygienic practices and strictly following standard medical procedures greatly reduces infection to a significant level although not all nosocomial infections are avoidable. The clinical spectrum caused by nosocomial pathogens depend on body site of infection, the involving pathogen and the patient's underlying condition. Structural and non structural virulence factors associated with the bacteria are responsible for the observed clinical manifestation. Bacteria isolation and characterization from appropriate clinical materials with antimicrobial susceptibility testing is the standard of laboratory diagnosis.

5HT3 antagonists for prophylaxis of postoperative nausea and vomiting in breast surgery: a meta-analysis

BACKGROUND

Postoperative nausea and vomiting (PONV) are distressing adverse events following breast cancer surgery with an incidence of up to 80%. 5HT 3 antagonists are commonly employed as drugs of first choice for PONV although there is no clear evidence favoring one pharmacological approach over another.

AIMS

The objective of this meta-analysis is to compare the efficacy of 5HT 3 antagonists against all non-5HT 3 antagonism-based pharmacological approaches as a preemptive strategy for PONV in women undergoing breast surgery.

DESIGN

Meta-analysis of Randomized Controlled Trials.

MATERIALS AND METHODS

Literature search was conducted through PUBMED, reference lists, and Cochrane Central Register of Controlled Trials till June 2010 to identify eligible studies. Trials comparing 5-HT 3 antagonists with placebo or active controls for prophylaxis against PONV in women undergoing breast surgery were included. Two reviewers extracted the data independently. Methodological quality of each trial was assessed using Jadad score.

RESULTS

Nineteen trials were included. All trials were of good methodological quality (Jadad score >3). 5HT 3 antagonists were found superior to placebo [Odds ratio (OR)=0.18 (0.13-0.26)] or active controls [OR=0.65 (0.47-0.91)] in the prevention of PONV. 5HT 3 antagonists were also superior to placebo in preventing nausea alone [OR=0.51 (0.34-0.76)], vomiting [OR=0.31 (0.20-0.47)] and the use of rescue antiemetics [OR=0.18 (0.11-0.28)]. No significant difference was observed in the use of rescue antiemetics as compared to active controls [0.59 (0.19 to 1.86)].

CONCLUSION

5HT 3 antagonists are superior to other pharmacological interventions for the prevention of PONV in patients undergoing breast surgery under general anesthesia.

Transesterification of edible, non-edible and used cooking oils for biodiesel production using calcined layered double hydroxides as reusable base catalysts

Fatty acid methyl esters (FAME) were produced from edible, non-edible and used cooking oils with different fatty acid contents by transesterification with methanol using calcined layered double hydroxides (LDHs) as solid base catalysts. Among the catalysts, calcined CaAl2-LDH (hydrocalumite) showed the highest activity with >90% yield of FAME using low methanol:oil molar ratio (<6:1) at 65 °C in 5 h. The activity of the catalyst was attributed to its high basicity as supported by Hammett studies and CO(2)-TPD measurements. The catalyst was successfully reused in up to four cycles. Some of the properties such as density, viscosity, neutralization number and glycerol content of the obtained biodiesel matched well with the standard DIN values. It is concluded that a scalable heterogeneously catalyzed process for production of biodiesel in high yields from a wide variety of triglyceride oils including used oils is possible using optimized conditions.

A study of warning letters issued to clinical investigators and institutional review boards by the United States Food and Drug Administration

BACKGROUND

Warning letters (WLs) issued by the US FDA (United States Food and Drug Administration) mention the nature of violations by clinical investigators and institutional review boards (IRBS) and can help as training tools.

METHODS

WLs issued by the US FDA between January 2005 and December 2010 to clinical investigators and IRBs were reviewed for various violation themes.

RESULTS

A total of 129 WLs were issued to investigators and 40 to IRBs. Among the WLs issued to investigators, 67 (51.95%) were issued for drug-related research and 62 (48.06%) were for device-related research. For investigators, deviation from the investigational plan was the most common violation (81%) followed by failure to maintain accurate and adequate case histories (58.1%) and then informed consent issues (48.06%). Among WLs issued to IRBs, failure to have and follow standard operating procedures (SOPs) was seen in 93.89% followed by issues pertaining to membership (59.4%). When compared to a similar study published in 2004, for clinical investigators, no improvement was seen with respect to deviation from the investigational plan and study supervision. However, a significant improvement was seen in reporting of adverse events to IRBs, and some improvement was seen in the area of informed consent. For IRBs, no improvement was seen in most areas which included maintaining and following SOPs, membership, quorum requirements, misuse of expedited review and informed consent.

CONCLUSION

WLs serve as indicators of an active regulatory agency which should translate into greater safety for participants in clinical trials. For developing countries with weak regulatory systems, these can serve as useful learning tools to help improve systems and put in patient safeguards.

Incidence of hypertension and its risk factors in rural Kerala, India: a community-based cohort study

OBJECTIVES

To investigate the incidence of hypertension and its risk factors in Kerala, India where the epidemiological transition is more advanced than elsewhere in India.

STUDY DESIGN

Prospective cohort study.

METHODS

A sample of 297 individuals (aged 15-64 years) in rural Kerala, India, who were free of hypertension at study enrolment, were followed-up from 2003 to 2010. At enrolment, demographic characteristics and behavioural risk factors were determined by interview, and the participants underwent physical (blood pressure, height, weight and waist circumference) and biochemical examinations (fasting plasma glucose and serum lipids). At follow-up, blood pressure readings were repeated using the original tool following the same protocol.

RESULTS

Nearly one-quarter (23.6%) of the sample developed hypertension over a mean follow-up period of 7.1 (standard deviation 0.2) years. Age ≥35 years [relative risk (RR) 4.00, 95% confidence interval (CI) 2.37-6.03], current smoking [RR 1.99, 95% CI 1.14-2.97, population-attributable risk percent (PAR%) 13.3%], high-normal blood pressure (RR 3.53 vs optimal blood pressure, 95% CI 2.17-5.28, PAR% 44.0%) and central obesity (RR 2.45, 95% CI 1.45-3.70, PAR% 40.4%) were significantly associated with incident hypertension. Collectively, current smoking, high-normal blood pressure and central obesity accounted for 70.1% of all new cases of hypertension. Awareness, treatment and control rates of incident hypertension were 42.9%, 22.9% and 11.4%, respectively.

CONCLUSIONS

This rural sample showed a high incidence of hypertension. This underscores the need for primary prevention of hypertension through lifestyle modification strategies targeting individuals with high-normal blood pressure, central obesity and current smoking. The healthcare system needs to improve the level of awareness, treatment and control of hypertension in this population.

Utility of PET in unknown primary with cervical metastasis: a retrospective study

BACKGROUND

FDG-PET is recommended as an investigation in unknown primary tumors, but its definitive role and cost effectiveness are yet to be established.

AIMS

dditional value of FDG-PET over conventional imaging in unknown primary tumors with cervical metastasis.

SETTING AND DESIGN

Retrospective study in a tertiary level oncology centre.

MATERIALS AND METHODS

A total of 112 patients were divided into three groups; 53 with conventional modalities (either computed tomography or magnetic resonance imaging) (group I), 59 with FDG-PET (group II), and group III (subgroup of group II) with both (40 patients).

STATISTICAL ANALYSIS

Sensitivity and specificity of both conventional modality and PET were calculated. Association between neck nodes and distant metastasis was analysed using multivariate logistic regression analysis.

RESULTS

Sensitivity and specificity for conventional modalities was 92.3% and 50% and sensitivity and specificity of FDG-PET was 92.8% and 71.4%, respectively. FDG-PET detected metastasis in 52.54% of patients. Multivariate logistic regression analysis showed statistically significant association between distant metastasis and multiplicity of nodes (N2b, N2c) (P = 0.007). Among all patients with low neck nodes in group II, FDG-PET detected primaries in 12 patients, 9 of which were infraclavicular (75%). FDG-PET added information to conventional imaging in 32.5% of patients and influenced an overall change in management in 38.9% of patients.

CONCLUSIONS

FDG-PET is a valuable tool influencing change of management in unknown primary with cervical metastasis. It is recommended especially in the presence of low or multiple neck nodes in view of high incidence of infraclavicular primary and distant metastasis, respectively.

Route to neo-inguinal canal: Our experience

AIM

The objective of this study was to stress the importance and value of this route to neo-inguinal canal creation for undescended testis management laparoscopically.

MATERIALS AND METHODS

Data from the Department of Paediatric Surgery, Coimbatore Medical College, was taken. Retrospective study was undertaken for the period 2004 to 2008. Here the surgical technique and outcome of the treatment are recorded for children aged 1 year to 12 years.

RESULTS

A total of 126 children underwent laparoscopic stage II surgery by this route (medial to the medial umbilical ligament). Right-sided undescended testis (UDT) was present in 76 (60%) patients. Left-sided UDT was present in 45 (35%) patients. Bilateral UDT was present in 5 (5%) patients. There were 90 (71%) patients aged less than 2 years and 36 (29%) patients aged more than 2 years. The eldest patient was 12 years of age. The overall hospital stay was 1 day. There were no complications seen in the follow-up. In all cases, the testis could not be brought down in a single stage.

CONCLUSION

Creation of neo-inguinal canal medial to the medial umbilical ligament and just lateral to the bladder has the advantage of gaining more length on the vessels and vas to bring the testis to scrotum. The laparoscopic management of undescended testis in stage II by this innovative new route is simple, less complicated and well tolerated.

Dosimetric comparison of linear accelerator-based stereotactic radiosurgery systems

Stereotactic radiosurgery (SRS) is a special radiotherapy technique used to irradiate intracranial lesions by 3-D arrangements of narrow photon beams eliminating the needs of invasive surgery. Three different tertiary collimators, namely BrainLab and Radionics circular cones and BrainLab micro multileaf collimator (mMLC), are used for linear accelerator-based SRS systems (X-Knife). Output factor (S(t)), tissue maximum ratio (TMR) and off axis ratio (OAR) of these three SRS systems were measured using CC01 (Scanditronix/ Welhofer) and Pinpoint (PTW) cylindrical and Markus plane parallel ionization chambers as well as TLD and radiochromic film. Measurement results of CC01 and Pinpoint chambers were very close to each other which indicate that further reduction in volume and physical dimensions of cylindrical ionization chamber is not necessary for SRS/SRT dosimetry. Output factors of BrainLab and Radionics SRS cones were very close to each other while output factors of equivalent diameter mMLC field were different from SRS circular cones. TMR of the three SRS systems compared were very close to one another. OAR of Radionics cone and BrainLab mMLC were very close to each other, within 2%. However, OARs of BrainLab cone were found comparable to OARs of Radionics cone and BrainLab mMLC within maximum variation of 4%. In addition, user-measured similar data of other three mMLC X-Knives were compared with the mMLC X-Knife data measured in this work and found comparable. The concept of switching over to mMLC-based SRS/SRT is thus validated from dosimetric characteristics as well.

Laparoscopic assisted anorectal pull through: Reformed techniques

AIM

To assess the modifications in the technique of laparoscopic assisted anorectal pull through (LAARP) practiced at our institute and analyze the post operative outcome and associated complications.

MATERIALS AND METHODS

A retrospective study from January 2001 to May 2009 analyzing LAARP for high anorectal malformations.

RESULTS

A total of 40 patients - 34 males and six females, in the age group of two months to six years were studied. Staged procedure was done in 39 patients; one child with recto vestibular fistula underwent single stage procedure. All the patients withstood surgery well. One patient required conversion due to problems in gaining enough length for the distal rectum in a patient with rectovesical fistula so colostomy was closed and re-located at a proximal splenic flexure. The complications were mucosal prolapse (six cases), anal stenosis (three), adhesive obstruction (two), distal rectal necrosis (one), and urethral diverticulum (one). The patients were followed up with clinical evaluation and continence scoring. The progress has been satisfactory and weight-gain is adequate.

CONCLUSIONS

THE ADVANTAGES OF THE REFORMED TECHNIQUES ARE AS FOLLOWS: Transcutaneous bladder stitch provides excellent visualization; traction over the fistula helps in dissection of the puborectalis, dividing the fistula without ligation is safe, railroading of Hegar's dilators over the suction canula creates adequate pull through channel, saves time and makes procedure simpler with reproducible comparable reports.

Optical coherent control induced by an electric field in a semiconductor: a new manifestation of the Franz-Keldysh effect

In (100)-oriented GaAs illuminated at normal incidence by a laser and its second harmonic, interference between one- and two-photon absorption results in ballistic current injection, but not modulation of the overall carrier injection rate. Results from a pump-probe experiment on a transversely biased sample show that a constant electric field enables coherent control of the carrier injection rate. We ascribe this to the nonlinear optical Franz-Keldysh effect and calculate it for a two-band parabolic model. The mechanism is relevant to centrosymmetric semiconductors as well.