Apneic Oxygenation in Diagnosis and Treatment of Lung Tumours in an Experimental Porcine Model

Objectives: Respiratory movements may complicate diagnostic and therapeutic procedures such as biopsies and stereotactic irradiation therapy in lung cancer patients. An attempt to avoid respiratory movements, up to 30 minutes, long enough for procedures was performed in an animal study.Methods: Ten anaesthetized minipigs ~30 kg were intubated in the trachea and small NiTi-stents were placed in various parts of the lungs. Using a muscle relaxing drug, the pigs were deprived of the ability to breathe for 30 minutes, a longer time than normally used for positioning and irradiation or for biopsies. No attempt to hyperventilate the animals was made prior to the apneic period. After a lung recruitment manoeuvre, a constant oxygen pressure of 20 cm water was applied to the airways. Using X-ray fluoroscopy, the position of the stents and thereby the movements of the lung, were monitored. Arterial gas analyses were performed every 5 minutes during the apneic period.Results: All animals survived 30 minutes of apneic oxygenation. The median arterial oxygen partial pressure actually rose from 11.8 to 54.3 kPa and there were no changes in oxygen saturation. The median arterial carbon dioxide partial pressure rose from 6.9 to 18.7 kPa and the median pH fell from 7.41 to 7.04 during 30 minutes of apneic oxygenation. Our setup, or our strategy of anaesthesia, did not immobilise the internal parts of the lungs satisfactorily, and must be improved before it can be used in a clinical situation. Conclusion: Physiologically, it is possible to stop respiration using apneic oxygenation for periods long enough to perform biopsies or stereotactic radiation therapy

Hybrid spectrum access with relay assisting both primary and secondary networks under imperfect spectrum sensing

This paper proposes a novel hybrid interweave-underlay spectrum access for a cognitive amplify-and-forward relay network where the relay forwards the signals of both the primary and secondary networks. In particular, the secondary network (SN) opportunistically operates in interweave spectrum access mode when the primary network (PN) is sensed to be inactive and switches to underlay spectrum access mode if the SN detects that the PN is active. A continuous-time Markov chain approach is utilized to model the state transitions of the system. This enables us to obtain the probability of each state in the Markov chain. Based on these probabilities and taking into account the impact of imperfect spectrum sensing of the SN, the probability of each operation mode of the hybrid scheme is obtained. To assess the performance of the PN and SN, we derive analytical expressions for the outage probability, outage capacity, and symbol error rate over Nakagami-m fading channels. Furthermore, we present comparisons between the performance of underlay cognitive cooperative radio networks (CCRNs) and the performance of the considered hybrid interweave-underlay CCRN in order to reveal the advantages of the proposed hybrid spectrum access scheme. Eventually, with the assistance of the secondary relay, performance improvements for the PN are illustrated by means of selected numerical results

Walsh-chirp sequences for wireless applications

This paper deals with a new method to design polyphase spreading sequences for DS CDMA wireless applications. The method is based on weighting symbols of the orthogonal Walsh sequences by the complex factors being symbols of baseband chirp sequences. The resulting sequences possess good aperiodic correlation properties, while maintaining the orthogonality. Because of the parametric design, the sequences can be optimized to achieve desired characteristics

Call quality monitoring for VoIP

A method of monitoring the speech quality of a Voice-over-IP call is described in this paper. This method is attractive because it employs the ITU-T standard P.862 for Perceptual Evaluation of Speech Quality which is well-known for its accuracy. In addition, with the proposed method, call quality is monitored without interfering with the call while it is in progress. The results corresponding to an implementation of this method shows call quality can be measured with excellent accuracy under typical network delays. © 2011 IEEE

MENTAL FATIGUES AFFECT ON REPEATED WINGATE ANAEROBIC TESTS

The fact that mental fatigue has an effect on cognitive and skilled performance is well known, but limited research has been conducted looking at the effects of mental fatigue on athletic performance. PURPOSE: To investigate if there are any effects on anaerobic power following a mental fatiguing test. METHODS: In this repeated measures counterbalanced designed study, 10 active, healthy, college-aged participants (7 males and 3 females) completed 2 Wingate Anaerobic Tests (WAT). Each participant reported to the lab on 3 separate occasions. The first lab visit consisted of obtaining descriptive data and conducting 2 WAT for familiarization. Each experimental trial started with 60 min of either a mentally fatiguing test (MF) or 60 min of watching a non-mentally fatiguing sitcom (CON). After each 60 min session the BORG RPE scale and the 20 question Swedish Occupational Fatigue Inventory (SOFI-20) were used to assess mental fatigue. Furthermore, we assessed Heart Rate (HR) and Blood Pressure (BP) every 10 min throughout the beginning 60 min of the MF trial and CON trial to quantify any physiological strain that may have occurred. Following the 60 min sessions, 2 WAT were performed with 5 min of low intensity cycling between each WAT. Immediately after each WAT, HR, BP, RPE, peak power output, fatigue index and average power were recorded. RESULTS: No differences were found between HR and BP during the 60 min MF trials and CON trials. However, RPE and SOFI-20 revealed a state of mental fatigue (p \u3c 0.05). Following each WAT, no differences were seen (p \u3e 0.05) between the different variables assessed following the MF trials and CON trials. CONCLUSION: Our findings show that mental fatigue did not have an impact on anaerobic power output; however, further research should be conducted looking at the affects of mental fatigue on athletic performance