Simultaneous rotary and linear displacement sensor based on soft pneumatic sensing chambers

Specific industrial or research applications necessitate specialized displacement measurement conditions, thereby driving researchers to innovate sensors based on novel operating principles. One such challenging condition is the prevalence of strong electromagnetic waves, which precludes using any sensor with a metallic structure or one that operates on electrical measurement principles. Additionally, space constraints in applications requiring multidimensional displacement measurements mandate the development of sensors capable of measuring displacements simultaneously in multiple directions. This paper introduces a novel soft sensor designed to simultaneously measure linear and rotational displacements using Soft Pneumatic Sensing Chambers (SPSCs). This sensor is unique in its ability to measure both linear and rotational movements and, due to its Electro-Magnetic Compatibility (EMC) and compact size, is suitable for environments with significant electromagnetic interference and spatial constraints. Furthermore, its flexibility makes it appropriate for body-interacting applications. The Abaqus software was employed to optimize the operating parameters. Subsequently, a laboratory setup was assembled, and the sensor's performance was assessed using two calibration methods: mathematical modeling and machine learning. According to the machine learning method, the accuracy in the linear and rotational directions was 0.49 mm and 5.4°, while the Root Mean Square Error (RMSE) was 0.05mm and 0.48°, respectively.

Artificial intelligence in cardiovascular medicine: An updated review of the literature

Screening and early detection of cardiovascular disease (CVD) are crucial for managing progress and preventing related morbidity. In recent years, several studies have reported the important role of Artificial intelligence (AI) technology and its integration into various medical sectors. AI applications are able to deal with the massive amounts of data (medical records, ultrasounds, medications, and experimental results) generated in medicine and identify novel details that would otherwise be forgotten in the mass of healthcare data sets. Nowadays, AI algorithms are currently used to improve diagnosis of some CVDs including heart failure, atrial fibrillation, hypertrophic cardiomyopathy and pulmonary hypertension. This review summarized some AI concepts, critical execution requirements, obstacles, and new applications for CVDs.

Tailoring Release Profiles of BCS Class II Drugs Using Controlled Release Amorphous Solid Dispersion Beads with Membrane-Reservoir Design: Effect of Pore Former and Coating Levels

Poor aqueous solubility is a major limiting factor during the development of BCS Class II drug candidates in a solid oral dosage form. Conventional amorphous solid dispersion (ASD) systems focus on maximizing the rate and extent of release by employing water-soluble polymeric crystallization inhibitors; however, they often encounter rapid supersaturation and solution-mediated phase transformation (SMPT). Therefore, in this work, a controlled release membrane was introduced onto ASD beads to mitigate the SMPT problem. A membrane-reservoir controlled release amorphous solid dispersion (CRASD) bead system was designed, and the effects of the coating thickness and pore former content on drug release profiles were investigated. CRASD beads were manufactured by spray-coating polyvinyl acetate with polyvinylpyrollidone (PVP) as a pore former onto sugar bead substrates layered with the ASD reservoir of celecoxib and PVP. Raising the pore former content and/or lowering the coating level imparted higher release rates and supersaturation levels. The extent of release, measured by the area under the curve, was greatest when an optimal balance between the release rate and peak concentration could be established, corresponding to a high pore former/high coating level combination. Attributed to a thicker membrane structure with a higher pore former, rapid initial release could be achieved, yet controlled gradually for several hours, avoiding the critical threshold where the onset of SMPT predominates. The greater membrane capacity to transiently immobilize drug molecules (i.e., preserve amorphicity) and gradually release drug over a prolonged duration may be key to balancing supersaturation on both sides of the membrane; hence coating variables should be tactfully selected to exploit this benefit.

Manufacturing of Dexamethasone-Poly(d,l-Lactide-co-Glycolide) Implants Using Hot-Melt Extrusion: Within- and Between-Batch Product Performance Comparisons

Purpose: Reliable drug therapy with injectable intravitreal implants requires implants of consistent quality. The purpose of this study was to prepare dexamethasone-poly(d,l-lactide-co-glycolide) (PLGA) biodegradable implants and assess implant quality within and between batches for different polymer compositions. Methods: Implants containing 20% w/w dexamethasone with 3 theoretical rates of release (fast, intermediate, and slow) were manufactured with decreasing proportion of acid-terminated PLGA (50:50) and increasing proportion of ester-terminated PLGA (50:50) in a batch process using hot-melt extrusion. The implants were manufactured without and with in-process modification of extrusion/conveyor speed in the late phase of each batch. Implant samples collected at early, middle, and late phases of each batch were analyzed for diameter, drug loading, mechanical properties (strength and toughness), and drug release. Results: With a fixed process, unlike a modified process with an increase in extrusion speed and reduction of conveyor speed in the late phase, all implant formulations tended to decrease in diameter and mechanical properties in the late phase. Drug release profiles for the intermediate and slow release compositions were similar with or without process modification, unlike the fast release composition. Addition of ester-terminated PLGA resulted in a slower drug release. When all formulations are grouped together, the implant diameter exhibited a moderate correlation with mechanical properties, but no correlation was observed with drug release. Conclusions: Within a hot-melt extrusion batch process, the dexamethasone-PLGA implant diameter and hence toughness and strength tend to decline in the latter phase. In-process adjustment of extrusion and conveyor speeds can improve batch consistency and, potentially, implant integrity or performance during or after injection. Process changes did not affect drug release for 2 of the 3 implant compositions.

Dexamethasone Degradation in Aqueous Medium and Implications for Correction of In Vitro Release from Sustained Release Delivery Systems

The in vitro drug release in an aqueous medium is a critical performance metric for a sustained release drug product. During long-term release studies, drugs may degrade in the release medium, and such degradation can lead to errors in drug release quantitation. Using dexamethasone as a model drug and LC-MS/MS methods employing dexamethasone-d₄ as an internal standard, this study identified that dexamethasone can degrade into 13 major degradation products in phosphate buffered saline (PBS) as a function of time, temperature (25, 37, and 45°C), and light exposure. A putative scheme for dexamethasone degradation pathways in PBS has been proposed. In proof-of-concept studies, the analytical method was used to quantitate dexamethasone and its degradation products during in vitro release studies with sustained release dexamethasone-poly(D,L-lactide-co-glycolide) (PLGA) implants incubated in phosphate buffer saline (PBS). Further, mathematical approaches were developed to estimate drug release from implants after accounting for drug degradation in PBS. The LC-MS/MS analytical method and the mathematical approaches developed could be used for assessing the stability and/or release of dexamethasone during manufacturing, storage, and use of various dosage forms.

Development of controlled release amorphous solid dispersions (CRASD) using polyvinyl acetate-based release retarding materials: Effect of dosage form design

The amorphous solid dispersion (ASD) technique has been employed to formulate poorly-soluble drugs, however, development of solid dosage forms with ASD is challenging due to the high propensity of amorphous drug to precipitate upon dissolution. Thus this work aimed to explore the potential of controlled release amorphous solid dispersion (CRASD) systems using polyvinyl acetate (PVAc) as a release-retarding excipient to mitigate the drug precipitation during dissolution of poorly water-soluble drugs. A number of solid oral CRASD dosage forms in different shapes and structures were prepared to contain spray-dried SD powders of a model BCS Class II drug, celecoxib (CEL), polyvinylpyrrolidone (PVP) and polyvinyl acetate (PVAc) which was incorporated in varying ways. In vitro dissolution tests were performed to investigate the effect of dosage form design on the dissolution/recrystallization profiles. The results indicated that despite nearly identical formulation compositions, the dissolution/recrystallization profiles could be tailored by changing the dosage form design. Matrix-form granules demonstrated greatest improvement of solubility appropriate for rapid drug release, while membrane-coated beads appeared to have the greatest potential for sustained release and thereby the least possibility of precipitation during dissolution. These results suggest that appropriate dosage form design of CRASD systems is of potential to reduce the problem of precipitation during dissolution of poorly soluble drugs.

Abstract P5-01-01: Real-time imaging of lymph node metastasis in response to systemic ezrin inhibitor treatment in breast cancer

Lymph node (LN) metastasis is a key driver of recurrence and survival in breast cancer (BC) patients. However, the mechanisms of metastatic dissemination of tumour cells from LNs to distant sites and their predictors of response to systemic therapy remain poorly understood, mainly due to a lack of non-invasive in vivo imaging models. We have recently described ezrin, a pro-metastatic crosslinker protein, as a regulator of tumour lymphangiogenesis and metastasis in BC (Breast Cancer Res. 2014; 16(5): 438). Furthermore, we demonstrated significant association of high ezrin expression with lymphovascular invasion in a cohort (n=63) of premenopausal patients with invasive BC (p =0.024). These findings prompted us to examine the role of ezrin in migration and invasion of metastatic tumour cells in LNs and their response to ezrin-targeted therapy. Using a locally accrued LN positive patient cohort (n=94), we demonstrated a significant association between high ezrin levels and reduced recurrence-free survival (univariate Log-rank test, p=0.033), suggesting that ezrin is a potential predictor of relapse in LN positive BC. To address the mechanistic role of ezrin in LN metastasis, we developed a novel intravital imaging model using a lymphatic reporter transgenic mouse (B6-prox1-mOrange2-pA-BAC) to examine the response of tumour-draining LN to anti-ezrin systemic therapy in real time. Next, we tested the effects of a small molecule ezrin inhibitor (NSC668394) in vitro and observed significant suppression of ezrin activation (p-T567) and cancer cell invasive phenotype. Intravital imaging of inguinal LN metastases, derived from subcutaneously implanted breast adenocarcinoma E0771-LMV (lung metastatic variant) cells, demonstrated significant reduction in mobility and invasiveness (Mann Whitney, p<0.0001) of metastatic cells following systemic treatment with NSC668394 (0.5 mg/kg at 24h and 8h prior to imaging). Interestingly, LN metastases engagement by host T cell (CD3+) was notably increased, whereas T cell mobility was not affected by ezrin inhibition. Our findings present a novel non-invasive imaging model to study the LN metastasis response to anti-cancer therapy in real time, and provide new insight into the role of ezrin as a potential anti-metastatic target in BC.

(Supported by CRS, CIHR, CBCF, BCAK, Queen's SRC).

Citation Format: Ghaffari A, Hoskin V, Mullins G, Greer P, Kiefer F, Madarnas Y, SenGupta S, Elliott B. Real-time imaging of lymph node metastasis in response to systemic ezrin inhibitor treatment in breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-01-01.

Iran's Bushehr Earthquake at a Glance

On 9 April 2013, an earthquake of 6.1 magnitude hit southwestern Iran near the city of Khvormuj and the towns of Kaki and Shonbeh in Bushehr province. The official disaster mitigation committee took immediate actions to coordinate rescue teams equipped with 24-hour medical air assistance. Overall, 160 victims were transferred to and treated in the Khvormuj hospital, while 139 survivors were transferred to the hospitals in Bushehr for specialized care. The survivors have been settled in temporary shelters with adequate primary supplies. Considering the hot climate of the area, immediate measures should be taken in order to avoid any further casualties particularly heatstroke, dehydration, diarrheal and vector-borne diseases.

Parametric modelling of cardiac system multiple measurement signals: an open-source computer framework for performance evaluation of ECG, PCG and ABP event detectors

The major focus of this study is to present a performance accuracy assessment framework based on mathematical modelling of cardiac system multiple measurement signals. Three mathematical algebraic subroutines with simple structural functions for synthetic generation of the synchronously triggered electrocardiogram (ECG), phonocardiogram (PCG) and arterial blood pressure (ABP) signals are described. In the case of ECG signals, normal and abnormal PQRST cycles in complicated conditions such as fascicular ventricular tachycardia, rate dependent conduction block and acute Q-wave infarctions of inferior and anterolateral walls can be simulated. Also, continuous ABP waveform with corresponding individual events such as systolic, diastolic and dicrotic pressures with normal or abnormal morphologies can be generated by another part of the model. In addition, the mathematical synthetic PCG framework is able to generate the S4-S1-S2-S3 cycles in normal and in cardiac disorder conditions such as stenosis, insufficiency, regurgitation and gallop. In the PCG model, the amplitude and frequency content (5-700 Hz) of each sound and variation patterns can be specified. The three proposed models were implemented to generate artificial signals with varies abnormality types and signal-to-noise ratios (SNR), for quantitative detection-delineation performance assessment of several ECG, PCG and ABP individual event detectors designed based on the Hilbert transform, discrete wavelet transform, geometric features such as area curve length (ACLM), the multiple higher order moments (MHOM) metric, and the principal components analysed geometric index (PCAGI). For each method the detection-delineation operating characteristics were obtained automatically in terms of sensitivity, positive predictivity and delineation (segmentation) error rms and checked by the cardiologist. The Matlab m-file script of the synthetic ECG, ABP and PCG signal generators are available in the Appendix.

Effect of age on semen parameters in infertile men after varicocelectomy

Background

The effectiveness of varicocelectomy in restoration of fertility and improvement of semen parameters is still controversial. The purpose of this study was to determine the effect of age on semen parameters following varicocelectomy in a group of infertile men.

Methods

Improvements in sperm count, morphology, and motility were studied in 67 infertile patients 4–10 months after varicocelectomy.

Results

The mean age of the patients was 30.48 ± 7.49 years. Significant improvements in total sperm count, percentage normal morphology, and motility were noted in all age groups (P < 0.05). Patients aged <25 years demonstrated the greatest increase in sperm counts, normal morphology, and motility following varicocelectomy. There was a significant negative correlation between age and sperm count, sperm morphology, and sperm motility (P < 0.05).

Conclusion

The effect of age on improvement in sperm parameters after varicocelectomy is inconsistent with some reports in the literature, and could be attributable to the duration of infertility prior to surgery; in the long term, varicoceles are known to have deleterious effects on testis biology.

A methodology for prediction of acute hypotensive episodes in ICU via a risk scoring model including analysis of ST-segment variations

The aim of this study is to detect Acute Hypotensive Episodes (AHE) and Mean Arterial Pressure Dropping Regimes (MAPDRs) using ECG signal and Arterial Blood Pressure waveforms. To meet this end, the QRS complexes and end-systolic end-diastolic pulses are first extracted using two innovative Modified Hilbert Transform-Based algorithms namely as ECGMHT and BPMHT. A new smoothing algorithm is next developed based on piecewise polynomial fitting to smooth the fast fluctuations observed in RR-tachogram, systolic blood pressure (SBP) and diastolic blood pressure (DBP) trends. Afterwards, in order to consider the mutual influence of parameters on the evaluation of shock probability, a Sugeno Adaptive Network-based Fuzzy Inference System-ANFIS is trained using Hasdai et al. (J Am Coll Cardiol, 35: 136–143, 2000) parameters as input, with appropriate membership functions for each parameter. Using this network, it will be possible to incorporate the possible mutual influences between risk parameters such as heart rate, SBP, DBP, ST-segment episodes, age, gender, weight and some miscellaneous factors to the calculation of shock occurrence probability. In the next step, the proposed algorithm is applied to 15 subjects of the MIMIC II Database and AHE and MAPDRs (MAP ≤ 60 mmHg with a period of 30 min or more) are identified. As a result of this study, for a sequence of MAPDRs as long as 20 min or more, there will exist a consequent high peak with the duration of 3–4 min in the corresponding probability of cardiogenic shock diagram.

Parallel processing of ECG and blood pressure waveforms for detection of acute hypotensive episodes: a simulation study using a risk scoring model

The aim of this study is to detect acute hypotensive episodes (AHE) and mean arterial pressure dropping regimes (MAPDRs) using electrocardiographic (ECG) signals and arterial blood pressure waveforms. To meet this end, the QRS complexes and end-systolic end-diastolic pulses are first extracted using two innovative modified Hilbert transform-based algorithms, namely ECGMHT and BPMHT. The resulting systolic and diastolic blood pressure pulses are then used to calculate the MAP trend. A new smoothing algorithm is developed, next based on piecewise polynomial fitting (PPF) to smooth the fast fluctuations observed in RR-tachogram and MAP trends. PPF algorithm operates by sequentially fitting N number of polynomials to the original signal and calculating the corresponding coefficients using the best linear unbiased estimation approach. In the next step, the proposed algorithm is applied to 15 subjects of the MIMIC II Database and AHE and MAPDRs (MAP ≤ 60 mmHg with a period of 30 min or more) are identified. As a result of this study, MAPDR is realised as a specific marker of cardiogenic shock, in that for a sequence of MAPDRs as long as 20 min or more, there will exist a consequent high peak with a duration of 3-4 min in the corresponding probability of cardiogenic shock diagram.

Lepromatous leprosy in a kidney transplant recipient: a case report

Leprosy is a chronic granulomatous disease of the skin and peripheral nerves caused by Mycobacterium leprae. Among mycobacterial infections, leprosy is rare in renal transplant recipients. Here, we report the manifestations of lepromatous leprosy in a 41-year-old renal transplant recipient. Before the renal transplant, the patient had recurrent bullous lesions on his extremities with no systemic complaints. He was on an immunosuppressive regimen that included prednisolone (1 mg/kg/d), cyclosporine (6 mg/kg), and mycophenolate mofetil (2000 mg/d), and had 2 serologically confirmed acute episodes of cytomegalovirus infection that responded favorably to intravenous ganciclovir. The density of his bullous skin lesions decreased after renal transplant. During his regular posttransplant visits, we noticed a decrease in his eyebrow hairs on their lateral margins bilaterally. Later, he developed generalized, symmetric, erythematous papules. With a positive acid-fast bacilli with Fite staining, the results of a skin biopsy showed diffuse foamy histiocyte infiltration in the dermis. These findings are compatible with lepromatous leprosy. After antileprosy therapy, no deterioration of renal allograft function or lepra reactions was noted in a 4-month follow-up. Clinicians should consider leprosy in the differential diagnosis of skin lesions in immunocompromised hosts, and in particular, solid organ transplant recipients in endemic areas.

Generalized peritonitis requiring re-operation after leakage of omental patch repair of perforated peptic ulcer

BACKGROUND/AIM

Peptic ulcer perforations are a common emergency, but available literature is silent on the exact definition, incidence, management, and complications of peritonitis due to omental patch leakage.

PATIENTS AND METHODS

Retrospective data were collected on 422 patients who underwent omental patch repair of perforated peptic ulcer between March 20, 1999 and March 20, 2006. The definitive diagnosis of perforated peptic ulcer and omental patch leakage was obtained at surgery.

RESULTS

Seventeen (4%) patients experienced generalized peritonitis due to omental patch leakage. Mean age was 60.6 years. Mortality rate was 29.4%, and the mean hospital stay was 23.6 days. Delay in surgical approach, shock on admission, and age were all significantly associated with increased mortality.

CONCLUSIONS

Peritonitis due to omental patch leakage can result in significant morbidity and mortality. The most common causes of omental patch leakage and operative procedures were unknown and reinsertion of omentum, respectively. Factors such as shock on admission or delayed surgery, have significantly contributed to fatal outcomes and need careful attention.

Predicting acute hypotensive episodes based on HR baroreflex model estimation

A new method to predict acute hypotensive episodes (AHE) is proposed in this paper. The AHE is defined as any period of 30 min or more during which at least 90% of mean arterial pressure (MAP) measurements are below 60 mmHg. Since arterial pressure has a direct correlation with heart rate through heart rate (HR) baroreflex and cardiovascular systems, any changes in MAP, directly affect HR and vice versa. Predicting HR using our developed model, the periods in which HR drops to the values less than 40 beat/min are detected. The demonstrated AHE data for twenty patients are picked to validate the proposed algorithm. Results show that the proposed method could truly predict occurrence of the AHE in 17 out of 20 cases analyzed. Results show reliable accuracy in predicting AHE in these patients.

Simultaneous spectrophotometric determination of paracetamol, phenylephrine and chlropheniramine in pharmaceuticals using chemometric approaches

BACKGROUND AND THE PURPOSE OF THE STUDY

The linear multivariate calibration models such as principal components regression (PCR) and partial least squares regressions (PLS1 and PLS2) due to the mathematical simplicity and physical or chemical interpretability are sufficient and generally preferred method for analysis of multicomponent drugs. In this study, simultaneous determination of paracetamol, phenylephrine and chlorpheniramine in pharmaceuticals using chemometric methods and UV spectrophotometry is reported as a simple alternative technique.

MATERIAL AND METHODS

Principal components regression (PCR) and partial least squares regressions (PLS1 and PLS2) were used for chemometric analyses of data obtained from the spectra of paracetamol, phenylephrine and chlorpheniramine between wavelengths of 200 to 400 nm at several concentrations within their linear ranges. The analytical performance of these chemometric methods were characterized by relative prediction errors and recoveries (%) and compared with each other.

RESULTS

PCR, PLS1 and PLS2 were successfully applied to a tablet formulation, with no interference from excipients as indicated by the recovery. However, the PLS1 shows better results due to its flexibility and mathematical principals.

CONCLUSION

The proposed methods are simple and rapid requiring no separation step, and can be easily used as an alternative in the quality control of drugs.

MEFV mutations in Iranian Azeri Turkish patients with familial Mediterranean fever

Familial Mediterranean fever (FMF) is an autosomal recessive autoinflammatory disorder with more than 60 disease-associated mutations in the responsible gene, MEFV. In the present study, we determined 15 MEFV mutations in Iranian Azeri Turkish FMF patients. Five hundred and twenty-four unrelated patients were tested for 15 known mutations in the MEFV gene using amplification refractory mutation system-polymerase chain reaction and polymerase chain reaction-restriction fragment length polymorphism methods. Thirty-five different genotypes were characterized among the studied patients. Of the alleles investigated, the most common mutation was p.M694V (42.4%), followed by p.V726A (17%), p.E148Q (16.2%), and p.M680I (c.2040G>C) (15.2%). The p.R761H mutation (4.7%) was found to be the most frequent among the rare mutations. The mutations p.M680I (c.2040G>A), p.I692del, p.M694del and p.K695R were not found in this cohort. The remaining mutations account for 7.7% of the identifiable mutations. Five different types of complex alleles were also identified. The results show the diversity and the frequency of the mutations in the Iranian Azeri Turkish FMF patients. The p.R761H mutation is rather prevalent in Azeri Turks; therefore, it should be included in the routine molecular diagnosis of FMF patients from this ethnic group.

Aetiology and outcome of elderly burn patients in tabriz, iran

Background. Geriatric patients, usually defined as being 65 years of age or over, now make up about 10% of the major burn population. Main aim. To conduct a prospective study of elderly burn patients, analysing the predictive value of age, gender, total body surface area (TBSA) burned, inhalation trauma, pre-morbid conditions, and mortality. Methods. A 10-year prospective study of burn victims hospitalized in a major burn centre in Iran was conducted to analyse the association between age, percentage TBSA burn, inhalation injury, the causes of the burns, pre-existing co-morbid conditions and the risk of death, and the epidemiology of the burns. Results. Three hundred and eighty patients aged 65 years and over were identified. The mean patient age was 71 years. There were 109 deaths overall (28.7%), the majority of which (74) were among patients with self-inflicted burns. Except for the incidence of the burns, there were no significant differences between males and females. The mean burn size (21.6%) was significantly larger in non-survivors than in survivors (49.5% vs 10.3%; p < 0.001). In these 380 elderly burn patients, when the TBSA burned exceeded 50% mortality reached 100%. Inhalation injuries were strongly associated with large burns and were present in the majority of flame-burn fatalities. There were no deaths related to scalds. Pre-morbid conditions had no statistically significant influence on mortality. Conclusion. Large burn size was the strongest predictor of mortality among elderly burn patients, followed by the presence of inhalation injury. This study showed that burn patients aged 65 years and over can achieve a good outcome.

Finding events of electrocardiogram and arterial blood pressure signals via discrete wavelet transform with modified scales

A robust electrocardiogram (ECG) wave detection-delineation algorithm that can be applied to all ECG leads is developed in this study on the basis of discrete wavelet transform (DWT). By applying a new simple approach to a selected scale obtained from DWT, this method is capable of detecting the QRS complex, P-wave, and T-wave as well as determining parameters such as start time, end time, and wave sign (upward or downward). In the proposed method, the selected scale is processed by a sliding rectangular window of length n and the curve length in each window is multiplied by the area under the absolute value of the curve. In the next step, an adaptive thresholding criterion is conducted on the resulted signal. The presented algorithm is applied to various databases including the MIT-BIH arrhythmia database, European ST-T database, QT database, CinC Challenge 2008 database as well as high-resolution Holter data gathered in the DAY Hospital. As a result, the average values of sensitivity and positive prediction Se = 99.84 per cent and P+ = 99.80 per cent were obtained for the detection of QRS complexes with an average maximum delineation error of 13.7, 11.3, and 14.0 ms for the P-wave, QRS complex, and T-wave respectively. The presented algorithm has considerable capability in cases of a low signal-to-noise ratio, high baseline wander, and in cases where QRS complexes and T-waves appear with abnormal morphologies. Especially, the high capability of the algorithm in the detection of the critical points of the ECG signal, i.e. the beginning and end of the T-wave and the end of the QRS complex was validated by the cardiologist and the maximum values of 16.4 and 15.9 ms were recognized as absolute offset error of localization respectively. Finally, in order to illustrate an alternative capability of the algorithm, it is applied to all 18 subjects of the MIT-BIH polysomnographic database and the end-systolic and end-diastolic points of the blood pressure waveform were extracted and values of sensitivity and positive prediction Se = 99.80 per cent and P+ = 99.86 per cent were obtained for the detection of end-systolic, end-diastolic pulses.

Electrically pumped hybrid evanescent Si/InGaAsP lasers

Hybrid Si/III-V, Fabry-Perot evanescent lasers are demonstrated, utilizing InGaAsP as the III-V gain material for the first time to our knowledge. The lasing threshold current of 300-mum-long devices was as low as 24 mA, with a maximal single facet output power of 4.2 mW at 15 degrees C. Longer devices achieved a maximal single facet output power as high as 12.7 mW, a single facet slope efficiency of 8.4%, and a lasing threshold current density of 1 kA/cm2. Continuous wave laser operation was obtained up to 45 degrees C. The threshold current density, output power, and efficiency obtained improve upon those of previously reported devices having a similar geometry. Facet images indicate that the output light is largely confined to the Si waveguide.

Three output port channel-drop filter based on photonic crystals

We present a photonic-crystal (PC) channel-drop filter (CDF) design based on 3x3 PC ring resonators. The normalized transmission spectra for single-ring and dual-ring configurations have been investigated using two-dimensional finite-difference time-domain (FDTD) technique in a square-lattice dielectric-rod PC structure. First, we investigate a single ring and we show that backward and forward dropping is possible in the third communication window. Then we add another ring and waveguide to develop a new CDF. This filter consists of an input and three outputs. Our FDTD simulation yields more than 85% efficiency over each output port.

Lack of bioequivalence between two aciclovir tablets in healthy subjects

OBJECTIVE

This study aimed to compare the systemic bioavailability of two aciclovir tablets, Rouz-Aciclovir (test) and Zovirax (reference), in 12 healthy volunteers.

METHODS

In a crossover design, each subject received a single oral dose of aciclovir 400 mg followed by a 7-day washout period. Plasma concentrations of aciclovir were measured for up to 12 hours using a validated high-performance liquid chromatography method with a lower limit of quantification of 50 microg/L.

RESULTS

The mean values of maximum plasma concentration (C(max)), time to C(max) (t(max)), area under the plasma concentration-time curve from time 0 to 12 hours (AUC(12)) and from time 0 to infinity (AUC(infinity)), and plasma half-life following administration of the test product were 999.6 microg/L, 2.08 h, 4911.2 microg/L . h, 5417.7 microg/L . h and 3.08 h, respectively, and for the reference product 775.8 microg/L, 2.58 h, 3862.1 microg/L . h, 4295.4 microg/L . h and 3.14 h, respectively. The test/reference geometric ratio for C(max) (90% CI) was 1.30 (97.1, 174.8). The test/reference geometric ratios for AUC(12) (90% CI) and AUC(infinity) (90% CI) were 1.26 (99.7, 159.1) and 1.24 (98.9, 155.6), respectively. Therefore, the 90% CIs of C(max), AUC(12) and AUC(infinity) were not within the acceptable range of 80 and 125 suggested by the US FDA bioequivalence guideline.

CONCLUSION

The results of the present study suggest that the aciclovir test product was not bioequivalent to the reference product. The exact reasons for this remain to be determined. However, we think the difference should be attributed to the difference in the type and amounts of ingredients used in the formulation that probably affect the contact time of aciclovir with the sites of absorption in the gut.

Preparation and characterization of free mixed-film of pectin/chitosan/Eudragit RS intended for sigmoidal drug delivery

Polyelectrolyte complex (PEC) film between pectin as an anionic polyelectrolyte and chitosan as a cationic species was prepared by blending two polymer solutions at weight ratio of 2:1 and then solvent casting method. Besides pectin/chitosan PEC film, Eudragit RS, pectin/Eudragit RS and pectin/chitosan/Eudragit RS films were also prepared by aforementioned method. In mixed-film formulations, a fixed weight ratio of 1:5 of pectin or pectin/chitosan complex to Eudragit RS was used. Characterizations of pectin/chitosan interaction in solution were investigated by turbidity and viscosity measurement and in the solid state by Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction (WAXRD) and thermogravimetric analysis (TGA). It was observed that the swelling profile of pectin/chitosan film was pH-dependent and its swelling ratio in phosphate buffer solution (PBS) pH 7.4 was about 2.5-fold higher than that of PBS pH 6.0. Formulation containing only pectin/chitosan could not protect free film from high swelling in the aqueous media, therefore, Eudragit RS as a water-insoluble polymer must be included in the mixed-film. The formation of PEC between pectin and chitosan resulted in a decrease in the crystallinity and thermal stability caused by the interactions between polyions. Drug permeation or diffusion studies were carried out using Plexiglas diffusion cell consisting of donor and acceptor compartments. Theophylline was selected as a model drug to measure permeability coefficient. Drug permeation through pectin/chitosan/Eudragit RS showed a sigmoidal pattern; whereas drug diffusion through pectin/Eudragit RS and Eudragit RS films followed a linear characteristic. The drug permeation through the ternary mixed-film showed a burst release upon exposure to PBS pH 6.0. This mixed-film formulation showed the potential for sigmoidal drug delivery with an initial, controllable slow release followed by a burst release immediately after the change in pH. The burst drug permeation might possibly be due to change in film's porosity.

Performance comparison of neural network training algorithms in modeling of bimodal drug delivery

The major aim of this study was to model the effect of two causal factors, i.e. coating weight gain and amount of pectin-chitosan in the coating solution on the in vitro release profile of theophylline for bimodal drug delivery. Artificial neural network (ANN) as a multilayer perceptron feedforward network was incorporated for developing a predictive model of the formulations. Five different training algorithms belonging to three classes: gradient descent, quasi-Newton (Levenberg-Marquardt, LM) and genetic algorithm (GA) were used to train ANN containing a single hidden layer of four nodes. The next objective of the current study was to compare the performance of aforementioned algorithms with regard to predicting ability. The ANNs were trained with those algorithms using the available experimental data as the training set. The divergence of the RMSE between the output and target values of test set was monitored and used as a criterion to stop training. Two versions of gradient descent backpropagation algorithms, i.e. incremental backpropagation (IBP) and batch backpropagation (BBP) outperformed the others. No significant differences were found between the predictive abilities of IBP and BBP, although, the convergence speed of BBP is three- to four-fold higher than IBP. Although, both gradient descent backpropagation and LM methodologies gave comparable results for the data modeling, training of ANNs with genetic algorithm was erratic. The precision of predictive ability was measured for each training algorithm and their performances were in the order of: IBP, BBP>LM>QP (quick propagation)>GA. According to BBP-ANN implementation, an increase in coating levels and a decrease in the amount of pectin-chitosan generally retarded the drug release. Moreover, the latter causal factor namely the amount of pectin-chitosan played slightly more dominant role in determination of the dissolution profiles.

Pectin/chitosan/Eudragit RS mixed-film coating for bimodal drug delivery from theophylline pellets: preparation and evaluation

Pellets containing theophylline as a model drug and microcrystalline cellulose, in a ratio of 6:4, were prepared by the extrusion-spheronization method. The pellets were coated with Eudragit RS aqueous dispersions, containing various amounts of pectin-chitosan complex and different coating mass gains, using a fluidized-bed apparatus. Twelve formulations were developed, which differed in two factors: coating mass gain (10, 15 and 20%, m/m) and the amount of pectin-chitosan complex (5, 10, 15 and 20%, m/m). Drug release studies were conducted using the USP apparatus I (basket) in dissolution media, mimicking the conditions prevailing in the stomach, small intestine or colon. Studies have shown that the drug release rate and pattern were dependent on both of the two mentioned factors. Some formulations showed bimodal and burst drug release, being triggered in the colonic medium by the action of pectinolytic enzymes. In formulations with 15 or 20% (m/m) of coating mass gain and 5 or 10% (m/m) of pectin-chitosan, the burst drug release was eliminated and replaced by the lag phase of drug release. In the case of burst drug release in the colonic medium, formulations with 20% (m/m) of coating mass gain and 15 or 20% (m/m) of pectin-chitosan were found to be better than the other formulations. Studies on the surface SEMs of uncoated and coated pellets show that after coating, coated pellets become smoother and exposure to pectinolytic enzymes in the colonic medium may result in surface erosion.