Extra Section Research Articles

Quality of life in adolescents with narcolepsy type 1– a transversal study in a tertiary hospital

Purpose– Narcolepsy type 1 (NT1) is a rare chronic sleep disorder, usually arising by adolescence that negatively impacts quality of life. It is characterized by excessive daytime sleepiness (EDS), cataplexy, hypnagogic/hypnopompic hallucinations, sleep paralysis and sleep fragmentation. The goals of this work were to characterize NT1 adolescents regarding sleep characteristics, health-related quality of life (HRQoL) and future life perspectives and later to compare this group with a control group of healthy adolescents (HA). Methods– Transversal descriptive/analytical study including NT1 patients followed in a sleep center of a tertiary hospital and 23 HA. Data were collected through an online survey, fulfilled by the participants, including four sections: demographics; questionnaire evaluating sleep and EDS; questionnaire evaluating HRQoL; inquiry regarding future perspectives. An extra section for the NT1 group only, comprising questions about the characterization of narcolepsy, was included. Results22 NT1 adolescents were included, with a median age of 15.0 years-old. Beyond EDS, all had presented cataplexy - 19 still reported it. Twenty patients took psychostimulants regularly for EDS, while 13 patients took venlafaxine or fluoxetine for cataplexy. Nineteen adolescents took regular naps and 19 maintained psychological appointments. Self-reported sleep quality was similar between groups (p = 0.112). EDS was identified in seven NT1 patients and none in the control group. HRQOL was significantly lower in NT1 patients only for the physical well-being domain (p = 0.001). Regarding future perspectives, results were similar, except for a lower probability of getting a driver's license in NT1 patients, despite no statistical significance (p = 0.104). DiscussionDaytime sleepiness is difficult to control in NT1, despite specialized treatment. HRQoL was similar between groups in all domains except for the physical well-being. Despite good adherence to pharmacological and non-pharmacological treatments (namely psychological therapy) that account for these good results, the physical well-being domain is difficult to manage.

Dual Band F-Antenna for Europe and North America

A single antenna for multiple bands are always beneficial from the design point of view. Here a single antenna which is fundamentally inverted F antenna is used, the uniqueness of the design is that , it uses trap technique to produce dual resonance from a single inverted F antenna . The trap used to block the current due to some frequencies and passes the current contributed by other frequencies. So in short , this trap is like a RF filter which has some passband as well as stop band. This trap approach uses a LC network to achieve this design goal .The two bands of interest are 865-870 MHz and 902-928 MHz .. The challenge of this design is that the frequency separation of the two bands is very small. In this case, and also the extra section for low frequency band is too small. Then, the influence of trap LC component variation due to tolerance to the two resonant frequencies is big, and so it is difficult to achieve good in band return loss within the LC tolerance. This is the main difficulty of this design. This issue is resolved by placing the low band section away from the end of the antenna. The antenna is designed on FR4 substrate material having thickness of 1.6 mm and hence it is a low cost solution which could use in various commercial applications which follows these bands.

Additional Turkic and Tungusic Borrowings into Yukaghir VII

In this seventh part of this paper series, additional Turkic (i.e. Yakut) and Tungusic (i.e. Ewen or Ewenki) loanword etymologies for the Yukaghir languages and dialects are presented and evaluated in semantic, phonological and other considerations and viewpoints. In summary, a total of ten Yakut borrowings, and two Tungusic borrowings are given, as well as one Yukaghir borrowing in Ewenki. An extra section of interest in this paper presents some new Tundra Yukaghir field data, and lastly some documentation corrections are again given.

Loop track: an infinite long track model

ABSTRACT This paper developed a track model called the ‘Loop Track’ that had a new function to simulate infinite long tracks without heavy data movement. The model was three-dimensional and considers rails, sleepers, ballast, subballast, and subgrade. Rails were modelled by using the Finite Element Method whilst all other components were modelled as equivalent rigid bodies connected by flexible force elements. The loop or infinite feature of the model was achieved by adding an extra boundary section to link the last node set to the first node set of the original track model. Case studies were conducted to simulate infinite long tracks and variable track conditions, as well as to determine the minimum track length required for different simulations. Results show that the recommended minimum track lengths for the simulated cases were 76 sleepers for vertical track dynamics and 301 sleepers for longitudinal track dynamics.

Tribological performance of eco-friendly friction materials with rice husk

The present paper addresses the tribological behaviour of new eco-friendly brake friction materials with rice husk (RH). Three formulations with different RH content (0%, 6% and 12%) were developed and subjected to the SAE J2522 test procedure, plus an extra high-temperature section, through a laboratory-scaled braking tribometer. At 300 °C, RH acted holding wear debris and improving wear resistance due to the formation of large contact plateaus. At 550 °C, RH's organic compounds degraded, leading to a greater material fade. Formulation 6% RH outperformed the others, showing the lowest wear. In this case, the effect of the hard and temperature resistant silica outweighed the degradation of the organic compounds.

Additional Turkic and Tungusic Borrowings into Yukaghir VI

In this sixth part of this paper series, additional Turkic (i.e. Yakut) and Tungusic (i.e. Ewen or Ewenki) lexical borrowings into the Yukaghir languages and dialects are presented and evaluated in semantic, phonological and other considerations and viewpoints, thus providing loanword etymologies. In summary, a total of fourteen Yakut borrowings, four Tungusic and three Russian borrowings are given. An extra section of interest deals in the etymologizing of up until now quite mysteriously named Yukaghir child and youth games, and lastly some etymological notes and documentation corrections are again given.

Double Meander Dipole Antenna Array with Enhanced Bandwidth and Gain

In this paper, a new design of high gain and wide bandwidth microstrip patch antenna array containing double meander dipole structure is proposed. Two in-phase resonant frequencies in the Ku-band (12–18 GHz) could be achieved in the double meander dipole array structure, which lead to enhance impedance bandwidth without costing extra design section. Besides, further enhanced gain of 2 dBi of the array over the entire operating frequency range has been achieved by introducing a double-layer substrate technique. The proposed antenna has been fabricated using the E33 model LPKF prototyping PCB machine. The measurement results have been performed, and they are in very good agreement with the simulation results. The measured –10 dB impedance bandwidth indicates that the array provides a very wide bandwidth which is around 30% at the center frequency of 15.5 GHz. A stable gain with a peak value of 10 dBi is achieved over the operating frequency range. The E- and H-plane radiation patterns are simulated, and a very low sidelobe level is predicted. The proposed antenna is simple and has relatively low-profile, and it could be a good candidate for millimeter wave communications.

Experimental investigation of combinational fans influencing on the effective ventilation in an undersea metro interval tunnel

Based on the metro undersea interval from Wawuzhuang Station to Guizhou Road Station of Qingdao Metro Line 1, a physical model system is built for the sake to further study the Ventilation and Smoke Exhaust System (VSES) of this interval tunnel. In the VSES experimental system, it gains data of variable frequencies inputting to fans, consumed-power values of fans, velocities in carriageways and SEDs (Smoke Exhaust Ducts), static pressure in carriageways under the conditions of the TP (Two Pressing-in) and TP+OE (Two Pressing-in + One Extracted-out) combinations of fans. The experimental data are shown that the static pressure field in horizontal carriageways has a symmetrical distribution, whose symmetry axis is as the plane of a smoke ceiling, whether TP or TP+OE. Under the TP+OE, the velocities in SEDs and carriageways are influenced dominantly by an extracted-out fan; two pressing-in fans of the TP combination influence mainly those velocities. A velocity is capable to dilute and coerce a smog flue. The pushing force of the smog flue is supplied by a pressing-in fan with consumed-power values, and another pressing-in fan with the lower values prevents this flue from another carriageway; furthermore, the pulling force of this flue is supplied by an extracted-out fan with the largest consumed-power values. The ratio of the total values of fans to the discharged volume flow rates in both SEDs is proposed as a new criterion, which can quantify VSES performance and is equivalent to airflow pressure; it is shown that the VSES performance of the TP+OE combination promotes gradually and becomes superior to one of the TP. Finally, it is advisory that the TP+OE should be a preferential combination of fans in designs and engineering situ management of extra length and large section tunnel ventilation.

Randomized Control Study of Extra Peritoneal Verses Trans Peritoneal Cesarean Section in View of Operative Morbidity

Introduction: Increase incidence of caesarean section is a major concern in todays era. Ceaser may be performed in one of the three way, by classic technique, by lower segment or by some form of extraperitoneal cesarean section. The earliest extraperitoneal technique used was Latzko’s as introduced by Dr Henry Burns. Extraperitoneal cesarean section is a useful method of preventing postoperative morbidity in form of infections & adhesions. Early ambulation , Start oral fluids immediately and get the patient out of bed as soon as the anesthesia worn off are supposed to be advantages of this new study of old technique. Objective: To evaluate advantages or disadvantages of extra peritoneal caesarean section over trans peritoneal caesarean section. Study Design: Single blinded Randomized prospective control triel were performed over 66 patients in our tertiary care institute. Intra operative complications morbidity and outcome compaired by scaling signs, symptoms & examination findings by single consultant. Results: Patients of ECS had better score for postoperative pain, ambulation & oral intake there were less requirement of analgesic in ECS group. Postoperative nausea, shoulder pain febril episodes peritonitis genitourinary tract infection & bowel discomfort were very minimal in ECS group compaire to TCS group. Conclusion: An extra peritoneal csection is definitely advantageous over transperitoneal approach of lower segment caesarean section. There is no need for postoperative starvation, and ileus after this method is rare. Early mobilization reduces the risk of thrombosis and shortens postoperative pain. Less pain makes early commencement of breastfeeding easier within the first hours after the operation. This will also help contraction and involution of the uterus. Early removal of stitches reduces the risk of infection and keloids.

Optical Sensing and Imaging of pH Values: Spectroscopies, Materials, and Applications.

This is the first comprehensive review on methods and materials for use in optical sensing of pH values and on applications of such sensors. The Review starts with an introduction that contains subsections on the definition of the pH value, a brief look back on optical methods for sensing of pH, on the effects of ionic strength on pH values and pKa values, on the selectivity, sensitivity, precision, dynamic ranges, and temperature dependence of such sensors. Commonly used optical sensing schemes are covered in a next main chapter, with subsections on methods based on absorptiometry, reflectometry, luminescence, refractive index, surface plasmon resonance, photonic crystals, turbidity, mechanical displacement, interferometry, and solvatochromism. This is followed by sections on absorptiometric and luminescent molecular probes for use pH in sensors. Further large sections cover polymeric hosts and supports, and methods for immobilization of indicator dyes. Further and more specific sections summarize the state of the art in materials with dual functionality (indicator and host), nanomaterials, sensors based on upconversion and 2-photon absorption, multiparameter sensors, imaging, and sensors for extreme pH values. A chapter on the many sensing formats has subsections on planar, fiber optic, evanescent wave, refractive index, surface plasmon resonance and holography based sensor designs, and on distributed sensing. Another section summarizes selected applications in areas, such as medicine, biology, oceanography, bioprocess monitoring, corrosion studies, on the use of pH sensors as transducers in biosensors and chemical sensors, and their integration into flow-injection analyzers, microfluidic devices, and lab-on-a-chip systems. An extra section is devoted to current challenges, with subsections on challenges of general nature and those of specific nature. A concluding section gives an outlook on potential future trends and perspectives.

High-Efficiency Reconfigurable Dual-Band Class-F Power Amplifier With Harmonic Control Network Using MEMS

This letter presents a novel reconfigurable, high-efficiency class-F power amplifier (PA) structure, using a commercial GaN-HEMT, that achieves dual-band configuration not only at the fundamental frequency but also at the harmonics. With a proper harmonic tuning structure, the need for an extra filtering section is eliminated, resulting in a high dual-band efficiency with a reduced number of components and size. The reconfigurable structure uses commercial single-pole-double-throw (SPDT) and single-pole-single-throw (SPST) MEMS switches optimally placed on the stubs to select between 900 and 1800 MHz. The reconfigurable PA achieves a measured power-added efficiency (PAE) of 69.5% and a power gain of 13.6 dB while delivering an output power of 39.1 dBm at 900 MHz. At 1800 MHz, the amplifier achieves a PAE of 57.9%, a power gain of 10.5 dB, and an output power of 38.5 dBm.

SAT-109 ELABORATION OF A TEXTURE-MODIFIED FOOD DIDACTIC TOOL FOR PATIENTS WITH END-STAGE KIDNEY DISEASE UNDERGOING HEMODIALYSIS IN GUANAJUATO, MEXICO, WHO HAVE MISSING TEETH

The role of an adequate food intake on the preservation of an optimal nutritional status in patients with chronic kidney disease (CKD) undergoing dialysis, has been well described and there is significant evidence sustaining that a poor nutritional status can be related to several diseases, such as protein energy wasting syndrome, sarcopenia, it has a strong association with increased risk of hospitalization, worse clinical outcomes and even mortality. In order to ensure an adequate nutritional status and considering oral feeding as the classic pathway, we found imperative the necessity to offer options to patients who have masticatory issues due to dental loss. CKD patients undergoing dialysis usually have multiple comorbidities like diabetes, hypertension, mineral and bone disorder, inflammation, malnutrition, protein energy wasting, uremia, etc., which combined with aging and poor hygiene could promote oral cavity problems as periodontitis, cavities, gum disease and dental loss. Dental loss affects nutritional status of CKD patients in dialysis by interfering with the right intake of nutritious food. While it is true that some patients usually modify the texture of their meals in order to make chewing easier, sometimes the resulting dishes contain higher amounts of liquids than those they should consume (e.g. soups and jelly), which makes controlling of daily liquid intake harder. Thus, we aimed to elaborate a texture-modified food didactic tool for patients with CKD under hemodialysis who have missing teeth. From previous evidence in clinical practice guidelines, systematic reviews and original papers about nutritional requirements, based on food-texture modifications useful for patients with dental issues or deglutition problems and given that some recommendations can be extrapolated for patients with masticatory problems, we elaborated a didactic tool for CKD under hemodialysis patients, with dental loss. Subsequently, pertinent adjustments for patients undergoing dialysis were made: adequate use of liquids, restriction on high sources of sodium, phosphorus and potassium, and the incorporation of protein supplements and specialized polymeric formulas. We elaborated a didactic tool, digital and printed version, where the food-texture modifications for CKD under hemodialysis patients are described: double cooking, dicing, mincing, shredding, grating, pureeing and shaking. An extra section was included, where we designed easy to chew preparations that incorporate protein supplements and specialized polymeric formulas. For each technique, we described the making process, lists of ingredients and foods that can be used, taking into account low sources of sodium, phosphorus and potassium, as well as products we recommend avoiding. We also developed suggestions based on the loss of dental pieces according to their masticatory function: incisives, canines, premolars, molars or a combination of them. As far as we know, this texture-modified food didactic tool is the first step to help chronic hemodialysis patients with missing teeth, to improve their intake using low sources of phosphorus, potassium and sodium and without using more liquids than those required, giving them supplemented easy to chew meals. The recommendations herein could be used for other dialysis therapies users and by healthcare providers.

On Pho lha nas Painted on Tsong kha pa’s Pictorial Biography

In “Tsong kha pa’s 15 Thangkas Pictorial Biography (Tsong kha pa rnam thar ras bris),” published in the 18th century, there is a single scene that is not supposed to be directly related to Tsong kha pa’s own achievements. The purpose of this investigation is to justify the relationship between Tsong kha pa’s pictorial biography and the contents of the paintings, which are considered to be a scene (the so-called Pho lha nas scene) related to Pho lha nas bSod nams stobs rgyas (1689–1747). As a result of collating references and iconographic materials, I am able to show that the “Pho lha nas scene” is irrelvant to Tsong kha pa’s own achievements, but is rather only an extra section. Furthermore, it is also clarified that it is a scene created when publishing the woodcuts of the Kanjur and Tanjur, based on Pho lha nas instructions. It is obvious that the extra scene in “Tsong kha pa’s Pictorial Biography” was dedicated to the remarkable achievements (bsNgo rten) of Pho lha nas.

Analysis of Relief Shading Tools and Methods for Terrain Representation

Abstract. One of the key roles in map creation belongs to terrain representation. Relief shading is a traditional manual technique allowing users to perceive the terrain in an intuitive and naturalistic way. With the advent of digital elevation models (DEM), analytical relief shading came into a wider use, since it is faster, requires less effort and delivers reproducible results. In contrast to manual relief shading, it often lacks clarity when representing heterogeneous landscapes with diverse landforms though. The goal of this ongoing project is to identify which relief shading techniques are suitable for depicting specific landforms. Techniques developed over time to surmount this limitation mainly include (but not limited to) terrain generalisation, light direction adjustments, contrast enhancement and terrain segmentation. Each of numerous methods is usually applied and performs better in a particular landscape and does not consider possible landscape diversity within an area hillshading is generated for. Thus, it is necessary to detect the right combination of tools and parameters providing the best results regarding the visual quality in each landscape type and to find a correlation between those methods and landforms they are applied to. In the frame of this project, existing methods to automatically perform relief shading are initially tested on sample areas. Having miscellaneous landforms within sample areas and rendering them in the best possible way leads us to understanding which features analytical hillshading has to inherit from the manual one. It is planned to generate shaded reliefs using different techniques and to show them to cartographers and laymen worldwide via an online survey to define which combination of tools and methods consistently provides better results in terms of visual quality in each landscape type. A large number of participants should minimise the subjectivity peculiar to relief shading depiction. As the project involves both laymen and specialists, the survey is complemented with an extra section of questions for specialists with a higher weight in the final feedback evaluation based on their deeper knowledge of the subject. Analysis of participants’ feedback is meant for creation of a series of rules to be applied to specific landform or landscape type. For landscape features the range of qualitative and quantitative parameters is used (e.g. DEM derivatives). Besides, the resulting shaded reliefs are also compared with the Swiss Federal Office of Topography manual shaded reliefs at different scales. As a result, a direct correlation between the values of landscape features and visual quality of relief shading is provided. Finally, it can be seen that a particular combination of tools and methods is ideal for a landscape type based on the level of its geomorphological complexity. This should give users a possibility to improve the automatically produced relief shading as a whole, to adjust its parts if different landforms are present, or to bring more focus to those landscape features that were not revealed by automatic hillshading.

Improving MLC PCM Performance through Relaxed Write and Read for Intermediate Resistance Levels

Phase Change Memory (PCM) is one of the most promising candidates to be used at the main memory level of the memory hierarchy due to poor scalability, considerable leakage power, and high cost/bit of DRAM. PCM is a new resistive memory that is capable of storing data based on resistance values. The wide resistance range of PCM allows for storing multiple bits per cell (MLC) rather than a single bit per cell (SLC). Unfortunately, higher density of MLC PCM comes at the expense of longer read/write latency, higher soft error rate, higher energy consumption, and earlier wearout compared to the SLC PCM. Some studies suggest removing the most error-prone level to mitigate soft error and write latency of MLC PCM, hence introducing a less dense memory called Tri-Level memory. Another scheme, called M-Metric, proposes a new read metric to address the soft error problem in MLC PCM. In order to deal with the limited lifetime of PCM, some extra storage per memory line is required to correct permanent hard errors (stuck-at faults). Since the extra storage is used only when permanent faults occur, it has a low utilization for a long time before hard errors start to occur. In this article, we utilize the extra storage to improve the read/write latency in a 2-bit MLC PCM using a relaxation scheme for reading and writing the cells for intermediate resistance levels. More specifically, we combine the most time-consuming levels (intermediate resistance levels) to reduce the number of resistance levels (making a Tri-Level PCM) and therefore improve write latency. We then store some error correction metadata in the extra storage section to successfully retrieve the exact data values in the read operation. We also modify the Tri-Level PCM cell to increase its read latency when the M-Metric scheme is used. Evaluation results show that the proposed scheme improves read latency by 57.2%, write latency by 56.1%, and overall system performance (IPC) by 26.9% over the baseline. It is noteworthy that combining the proposed scheme and FPC compression method improves read latency by 75.2%, write latency by 67%, and overall system performance (IPC) by 37.4%.

On the standard model group in F-theory

We analyze the standard model gauge group \(SU(3)\times SU(2) \times U(1)\) constructed in F-theory. The non-Abelian part \(SU(3) \times SU(2)\) is described by a surface singularity of Kodaira type. Blow-up analysis shows that the non-Abelian part is distinguished from the naïve product of \(SU(3)\) and \(SU(2)\), but that it should be a rank three group along the chain of \(E_n\) groups, because it has non-generic gauge symmetry enhancement structure responsible for desirable matter curves. The Abelian part \(U(1)\) is constructed from a globally valid two-form with the desired gauge quantum numbers, using a similar method to the decomposition (factorization) method of the spectral cover. This technique makes use of an extra section in the elliptic fiber of the Calabi–Yau manifold, on which F-theory is compactified. Conventional gauge coupling unification of \(SU(5)\) is achieved, without requiring a threshold correction from the flux along the hypercharge direction.

On-Chip Miniaturized Diplexer Using Jointed Dual-Mode Right-/Left-Handed Synthesized Coplanar Waveguides on GIPD Process

A new on-chip miniaturized diplexer, implemented on glass-based integrated passive device (GIPD) process using dual-mode right- and left-handed synthesized coplanar waveguides (CPWs), is proposed and validated. The right-handed synthesized CPW is identical to a 50-Ω line in the low band but resembles an open circuit in the high band. The left-handed one, on the contrary, serves as an open circuit in the low band but becomes equivalent to a 50-Ω line in the high band. This unique property makes the proposed design require no extra matching section. The on-chip diplexer shows a very compact size of 0.0174 × 0.0171 λg2, along with low power dissipation (0.6-0.8 dB) and moderate operating bandwidth (11-19%) at 2.6/5.8 GHz.

Service quality and customer satisfaction in the health care industry - towards health tourism market

The purpose – Service quality and customer satisfaction have been extensively researched in the profit sector, but are also important in the non-profit sector. Specialty hospitals and health spas operate in the non-profit sector in Croatia, but some of them try to provide a part of their services to the health tourism market. Hospitals that work in the non-profit sector and especially those that see their future in the health tourism market need to pay attention to service quality and customer satisfaction. Although specialty hospitals are a vital segment of the Croatian health system, there has not been enough research regarding service quality and customer satisfaction measurement in that sector. Therefore, the purpose of this study is to assess the impact of service quality on customer satisfaction in the healthcare sector. Design/methodology – Empirical research is used to determine patients’ perceptions and expectations of service quality in one specialty hospital for medical rehabilitation. SERVQUAL instrument was used to measure the service quality. The SERVQUAL questionnaire included an expectations and perceptions section, each consisting of 34 statements. In addition, the questionnaire contained an extra section relating to demographics and an overall question on the impression of quality of the service provided. One hundred and four (104) satisfactorily completed questionnaires were collected. Findings – The analysis revealed that patients perceived a rather satisfactory level of health care quality across all SERVQUAL dimensions. Patients who perceived a higher level of service quality show greater satisfaction with the services, as well as a higher level of loyalty to the hospital which provides medical services. Research results indicate the multidimensionality of the concept and the existence of a gap between patients' expectations and the perceptions of service quality. Finally, despite the criticism of the SERVQUAL instrument, this study confirms the usefulness of the SERVQUAL model in terms of its reliability and validity for measuring quality in the health care sector. Originality of the research – This paper sheds light on a poorly researched field in the Croatian context. The specific environment in which the research was done demanded the implementation of a modified SERVQUAL model which was broadened with the items referring to sports, recreation and amusement activities. Theoretical contribution of this paper is reflected in testing the dimensionality and reliability of the modified SERVQUAL instrument for measuring service quality in a specialty hospital. It was found that the modified model has four dimensions. The ‘Output quality’ dimension, which refers to the services outside the sphere of medical services, has the greatest impact on the patients’ satisfaction. The practical contribution of the paper is manifested as an encouragement for managers in specialty hospitals to devote greater attention to service quality and customer satisfaction measurement, especially when their goal is to enter the health tourism market. It provides directions for hospital managers to develop strategies which will meet patients’ expectations of service quality and increase their competitiveness in the health tourism market.

Performance and cost evaluation of a new double-effect integration of multicomponent bioethanol distillation

Bioethanol derived from sugarcane is the most advanced alternative to fossil fuels and part of the solution in the efforts to achieve a low-carbon emissions world. Since distillation accounts for a large part of total energy consumption by industry, the need to reduce energy requirements serves as motivation for the study of this process. Many energy efficient schemes have been developed with this aim. However, most of them focus on columns working under pressure. Due to the organic nature of sugarcane and also to the liming process to which its juice is submitted, significant fouling can result from the insolubility of calcium salts, which is intensified at higher temperatures. In this work, Aspen Plus® was used to investigate the energy requirement of a configuration of double-effect forward-integrated columns, considering an extra stripping section to reduce the risk of fouling. The wine was considered a multicomponent mixture. Response surface methodology was applied to optimize the process and analyze some operating parameters. The configurations studied were adequate, but involved higher investments. The total annual costs were observed to be lower than those of a conventional process. Finally, congeners tended to have a negative effect on the specific steam consumption of the process.

Multifraction separation in countercurrent chromatography (MCSGP)

The multicolumn countercurrent solvent gradient purification (MCSGP) process is a continuous countercurrent multicolumn chromatography process capable of performing three fraction separations while applying a linear gradient of some modifier. This process can then be used either for the purification of a single species from a multicomponent mixture or to separate a three component mixture in one single operation. In this work, this process is extended to the separation of multifractions, in principle with no limitation. To achieve this goal the MCSGP standard process is extended by introducing one extra separation section per extra fraction to be isolated. Such an extra separation section is realized in this work through a single additional column, so that a n fraction MCSGP process can be realized using a minimum of n columns. Two separation processes were considered to experimentally demonstrate the possibility of realizing a four-fraction MCSGP unit able to purify two intermediate products in a given multicomponent mixture. The first one was a model mixture containing four different proteins. The two proteins eluting in the center of the chromatogram were purified with yields equal to 95% for the early eluting and 92% for the later eluting one. The corresponding purities were 94% and 97%, respectively. Such performance was well superior to that of the batch operation with the same modifier gradient which for the same purity values could not achieve yields larger than 67% and 81%, respectively. Similar performance improvements were found for the second separation where two out of seven charge variants which constitute the mAb Cetuximab currently available on the market have been purified in one single operation using a four-fraction MCSGP unit. In this case, yields of 81% and 65% were obtained with purities of 90% and 89%, respectively. These data compare well with the corresponding data from batch chromatography where with the same gradient and for the same purities, yield values not larger than 49% and 34%, respectively, could be achieved.