1.1 32 info:srw/schema/1/mods-v3.3xml journalArticle published yes 5 Martin Persson author 31ec7f7b-7095-4a14-8f05-798610ceff34 Jonathan Sandy author Nicky Kilpatrick author Magnus Becker author 29d44712-dfc6-4f6c-9f58-5cc39b4925f8 Henry Svensson author c5f1e34e-754e-44d1-b42b-d99e4ea97159 Surgery v1000516 department Department of Clinical Sciences, Malmö v1000476 department Surgery research group The aim of this retrospective population-based study was to determine if there is any significant difference in academic achievement between students with a Pierre Robin Sequence (PRS) compared with the general population of Swedish students at the typical time of graduation from compulsory school (usually at 16 years of age). The data were obtained from the Swedish Medical Birth Register for the years 1973-1986 and linked to the Swedish School-Grade Register, which generated a data set of 68 individuals with PRS that were compared with a control group consisting of 1,249,404 individuals. The following outcomes were measured: not receiving a school leaving certificate; their odds of receiving lowest grade; and reduced odds of receiving high grade in the following subjects: mathematics; English; Swedish; and physical education, and their grade point average. For the control group 2.74% did not receive their leaving certificate, while for the individuals with PRS 9.68% (OR = 4.00; 95% CI = 1.81 - 8.86) did not receive their leaving certificate. There were no differences between the groups in mathematics, English, and Swedish, while, in physical education, individuals with PRS had significantly reduced odds of receiving a high grade in the relative grading system. Individuals with PRS had a significantly lower grade point average: 3.00 +/- 0.09 in comparison to the control group: 3.23 +/- 0.002, p = 0.002. This study indicates that individuals with PRS experience significant difficulties in their educational achievements in compulsory school in Sweden. https://portal.research.lu.se/en/publications/55e07370-e630-4e3f-88a9-7dd7a3ba8a7f Medical Journals Sweden AB 2013 eng Pierre Robin Sequence education compulsory school school performance academic achievement psychology Surgery http://www.ncbi.nlm.nih.gov/pubmed/23210498 2000-656X 3591147 000313681700006 84872711124 23210498 10.3109/2000656X.2012.729216 http://dx.doi.org/10.3109/2000656X.2012.729216 yes 47 1 36 39 https://www.scopus.com/pages/publications/84872711124 The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Surgery Research Unit (013242220), Reconstructive Surgery (013240300) 55e07370-e630-4e3f-88a9-7dd7a3ba8a7f 2016-04-01T10:16:04+02:00 2025-10-14T10:23:41+02:00 2016-04-01T10:16:04+02:00 1 info:srw/schema/1/mods-v3.3xml journalArticle published 3 Martin Persson author Magnus Becker author 29d44712-dfc6-4f6c-9f58-5cc39b4925f8 Henry Svensson author c5f1e34e-754e-44d1-b42b-d99e4ea97159 Surgery v1000516 department Surgery research group https://portal.research.lu.se/en/publications/ab155ef5-4cd8-45c6-ac3c-fcad2d306654 SAGE Publications 2014 eng Surgery 1545-1569 4598798 000339123300020 84900396674 23919522 10.1597/13-149 http://dx.doi.org/10.1597/13-149 yes 51 3 367 368 https://www.scopus.com/pages/publications/84900396674 ab155ef5-4cd8-45c6-ac3c-fcad2d306654 2016-04-01T10:42:29+02:00 2025-10-14T12:37:58+02:00 2016-04-01T10:42:29+02:00 2 info:srw/schema/1/mods-v3.3xml journalArticle published yes 6 Hongxing Xu author 76906a4d-12ee-444b-b372-2cfe05c36122 X Wang author Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 M Kall author P Johansson author Solid State Physics v1000623 department We present a general model study of surface-enhanced resonant Raman scattering and fluorescence focusing on the interplay between electromagnetic effects and the molecular dynamics. Our model molecule is placed close to two Ag nanoparticles and has two electronic levels. A Franck-Condon mechanism provides electron-vibration coupling. Using realistic parameter values for the molecule we find that an electromagnetic enhancement by 10 orders of magnitude can yield Raman cross sections sigma(R) of the order 10(-14) cm(2). We also discuss the dependence of sigma(R) on incident laser intensity. https://portal.research.lu.se/en/publications/facbb191-987a-40d4-aa7f-84a9f696d225 American Physical Society 2004 eng Condensed Matter Physics (including Material Physics, Nano Physics) 1079-7114 259132 000225661100020 37649030540 15697802 10.1103/PhysRevLett.93.243002 http://dx.doi.org/10.1103/PhysRevLett.93.243002 yes 93 24 243002 https://www.scopus.com/pages/publications/37649030540 facbb191-987a-40d4-aa7f-84a9f696d225 2016-04-01T11:39:41+02:00 2025-10-14T10:48:30+02:00 2016-04-01T11:39:41+02:00 3 info:srw/schema/1/mods-v3.3xml journalArticle published yes 2 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 Solid State Physics v1000623 department We report a theoretical study of the electronic structure of GaAs nanowhiskers, grown in the [111] direction with hexagonal cross section, based on a tight binding approach. It is shown that the band structure of the GaAs nanowhiskers shifts from a direct band gap to an indirect band gap when the lateral size of the nanowhiskers becomes smaller than a certain value. The effective masses of the electrons and holes are shown to increase with decreasing the nanowhisker lateral size. It is also shown that the light-hole states appear to be at the top of the valence bands. The electrical and optical properties of the nanowhiskers are discussed in terms of the results of the calculations. (C) 2002 American Institute of Physics. https://portal.research.lu.se/en/publications/62d711e3-5412-4a73-ba5a-e8bcb9ff8406 American Institute of Physics (AIP) 2002 eng Condensed Matter Physics (including Material Physics, Nano Physics) 0003-6951 332162 000177284400052 79956000430 10.1063/1.1498871 http://dx.doi.org/10.1063/1.1498871 yes 81 7 1309 1311 https://www.scopus.com/pages/publications/79956000430 62d711e3-5412-4a73-ba5a-e8bcb9ff8406 2016-04-01T12:19:55+02:00 2025-10-14T10:36:52+02:00 2016-04-01T12:19:55+02:00 4 info:srw/schema/1/mods-v3.3xml conference paper published yes 2 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 Solid State Physics v1000623 department Proceedings of the 19th Nordic Semiconductor Meeting We report on a theoretical study of the electronic structure of silicon nanocrystals with a shape of the regular rhombic dodecahedron, based on a tight-binding method. The energies of the lowest unoccupied state and the highest occupied state have been calculated. We have shown that the six-fold degenerate conduction band minima of the bulk silicon crystal are split into a non-degenerate A(1) state, a double-degenerate E state and a triple-degenerate T-2 state and that the ordering of the energies of these states depends on the size of the silicon nanocrystal. Thus the lowest unoccupied state of the silicon nanocrystal can have different symmetries at different nanocrystal sizes. However. as the size of the nanocrystal changes, the symmetry of the highest occupied state remains the same; it is T-2 symmetric. The wave functions of the lowest unoccupied and highest occupied states have also been calculated. It is shown that these states have very different localization properties. The wave function of the lowest unoccupied A(1) state is largely localized on the central atomic site and on its nearest neighbors. In contrast, the wave function of the lowest unoccupied E state has no contribution from the orbitals of the central atom. Furthermore, the wave functions of both the lowest unoccupied and the highest occupied T-2 states are distributed more evenly over a large portion of the silicon nanocrystals. https://portal.research.lu.se/en/publications/fec74dd9-69fc-4e3d-af10-705c585e6757 Royal Swedish Academy of Sciences 2002 2001-05-20 - 2001-05-23 Lyngby, Denmark eng Wave functions Condensed Matter Physics (including Material Physics, Nano Physics) 0031-8949 1402-4896 322738 000179465600039 0036437376 10.1238/Physica.Topical.101a00147 http://dx.doi.org/10.1238/Physica.Topical.101a00147 yes T101 147 150 https://www.scopus.com/pages/publications/0036437376 fec74dd9-69fc-4e3d-af10-705c585e6757 2016-04-01T12:29:54+02:00 2026-01-03T02:58:39+01:00 2016-04-01T12:29:54+02:00 5 info:srw/schema/1/mods-v3.3xml journalArticle published yes 4 Erik Lind author 58f5e3ae-45b0-4599-9fee-c72f17e8b141 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Yann-Michel Niquet author Lars-Erik Wernersson author df6a486d-cb71-4d90-b84b-a2115a5761bf Department of Electrical and Information Technology v1000242 department Solid State Physics v1000623 department We have investigated the scaling properties of [111] InAs nanowire MOSFETs in the ballistic limit. The nanowire band structure has been calculated with an Sp(3)d(5)s* tight-binding model for nanowire diameters between 2 and 25 nm. Both the effective band gap and the effective masses increase with confinement. Using the atomistic dispersion relations, the ballistic currents and corresponding capacitances have been calculated with a semianalytical model. It is shown that the InAs nanowire MOSFET with diameters scaled below 15-20 nm can be expected to operate close to the quantum capacitance limit, assuming a high-kappa dielectric thickness of 1-1.5 nm. We have also investigated the evolution of f (t) and the gate delay, both showing improvements as the device is scaled. The very small intrinsic gate capacitance in the quantum limit makes the device susceptible to parasitic capacitances. https://portal.research.lu.se/en/publications/96fa597e-c487-4e7d-89d5-0c6df2febef1 IEEE - Institute of Electrical and Electronics Engineers Inc. 2009 eng Band structure field-effect transistor (FET) InAs nanowire Condensed Matter Physics (including Material Physics, Nano Physics) Electrical Engineering, Electronic Engineering, Information Engineering 0018-9383 1311479 000262816800007 59949097581 10.1109/TED.2008.2010587 http://dx.doi.org/10.1109/TED.2008.2010587 yes 56 2 201 205 https://www.scopus.com/pages/publications/59949097581 96fa597e-c487-4e7d-89d5-0c6df2febef1 2016-04-01T14:53:46+02:00 2025-11-27T15:41:51+01:00 2016-04-01T14:53:46+02:00 6 info:srw/schema/1/mods-v3.3xml journalArticle published yes 3 Martin Persson author 31ec7f7b-7095-4a14-8f05-798610ceff34 Magnus Becker author 29d44712-dfc6-4f6c-9f58-5cc39b4925f8 Henry Svensson author c5f1e34e-754e-44d1-b42b-d99e4ea97159 Surgery v1000516 department Department of Clinical Sciences, Malmö v1000476 department Surgery research group We report the weight, stature, body mass index (BMI), and muscular strength of men about 19 years old who have cleft lip, either with or without cleft palate (CLP), or cleft palate only (CP). Data were obtained from the Swedish National Service enrolment register for the years 1991 - 97, and concerned 335 men with CLP and 88 with CP, who were compared with a control group of 272 879 men. The data showed that those with CLP and CP were significantly lighter than controls. Their stature in the CLP group was similar to that in controls, but those with CP significantly shorter. These findings imply that men with CLP had a significantly lower BMI whereas men with CP had a similar BMI compared with controls. Those with CLP did not differ as regards to muscular strength, but those with CP were significantly weaker than controls. https://portal.research.lu.se/en/publications/2630f3da-8d4d-4bf2-b4cf-b6e4865e9999 Medical Journals Sweden AB 2007 eng Body Mass Index Body Weight Cleft Palate: physiopathology Cleft Lip: physiopathology Body Height Adult Male Humans Surgery http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=17484178&dopt=Abstract yes 1651-2073 168385 000244243100002 33847053948 10.1080/02844310601000002 http://dx.doi.org/10.1080/02844310601000002 yes 41 1 41434 41434 https://www.scopus.com/pages/publications/33847053948 The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Emergency medicine/Medicine/Surgery (013240200), Reconstructive Surgery (013240300), Surgery Research Unit (013242220) 2630f3da-8d4d-4bf2-b4cf-b6e4865e9999 2016-04-01T16:42:35+02:00 2025-10-14T10:41:33+02:00 2016-04-01T16:42:35+02:00 7 info:srw/schema/1/mods-v3.3xml theses published In the lecture hall at the Department of Medicine, entrance 35, Malmö University Hospital, Malmö 1 Martin Persson author 31ec7f7b-7095-4a14-8f05-798610ceff34 Henry Svensson supervisor c5f1e34e-754e-44d1-b42b-d99e4ea97159 Magnus Becker supervisor 29d44712-dfc6-4f6c-9f58-5cc39b4925f8 Professor Nichola Rumsey opponent Center for Appearance Research, University of the West of England, Bristol. Department of Clinical Sciences, Malmö v1000476 department In study I, 55 adolescents with cleft lip and palate and 31 adolescents without cleft filled out two questionnaires: the Tennessee Self-Concept Scale to assess self-concept, and the Eysenck Personality Questionnaire Inventory to assess the degree of introversion. In studies II &amp; III, data regarding physical characteristic and general intellectual capacity were obtained from the Swedish National Service Enrolment Register for the years 1991-97. Data concerned 335 men with cleft lip with or without clef palate and 88 with cleft palate. They were compared with a control group of 272 879 men without cleft. In study IV, data regarding academic achievement at the time of leaving compulsory education were obtained by linking the Swedish Medical Birth Register for the years 1973-86 with the Swedish School Grade Register. Data concerned 651 individuals with cleft lip, 830 with cleft lip and palate, and 511 with cleft palate. They were compared with a control group consisting of 1 249 404 individuals without cleft.<br/><br> <br/><br> In summary, we found that adolescents with cleft seem to have a normal to high self-concept without an accentuated degree of introversion (I). A cleft influences body dimensions, particularly in the cleft palate group where weight, statue, and muscle strength (II) showed lowered values, this may be correlated to their reduced achievement in physical education at school (IV). The general intellectual capacity (III) supports other studies that individuals with cleft palate have certain cognitive difficulties while the academic achievement (IV) indicated that adolescents with cleft experience difficulties in their educational achievements. <b>Popular Abstract in Swedish</b><br/><br> Det kan finnas en risk för att enskilda individer med läpp-käk-gomsplalt (LKG) kan möta problem ur psykosocial synpunkt som en konsekvens av den medfödda avvikelsen. LKG är en av de vanligaste medfödda avvikelserna och sett ut den synpunkten synes det viktigt att närmre undersöka detta antagande. Detta leder till den viktiga frågan om det är LKG-spalten som sådan som är avgörande eller om det även<br/><br> <br/><br> finns andra faktorer i bilden som spelar roll. Även om psyklogiska och funktionella aspekter som är direkt relaterade till spalten kan vara viktiga, så valde vi att inom föreliggande arbete också belysa andra faktorer som skulle kunna bidra till en försvårad anpassning ur psykosocial synpunkt för den enskilde. Följande studier genomfördes därför:<br/><br> <br/><br> I studie I fyllde 55 ungdomar (17 till 20 år gamla) med LKG och 33 ungdomar (16 till 19 år gamla) utan LKG i två enkäter; Tennessee Self-Concept Scale som uppskattar självkänsla, och Eysenck Personality Questionnaire Inventory som uppskattar introversion. I studierna II&amp;III analyserades avidentifierade data angående fysiska karaktärer (vikt, längd, body mass index, muskel styrka) samt generell intellektuell kapacitet från mönstringsregistret under åren 1991 ? 1997. Materialet inkluderade 335 män med läppspalt med eller utan gomspalt och 88 med gomspalt. Dessa jämfördes med en kontroll grupp på 272 879 män utan spalt. I studie IV analyserades avidentifierade data angående utbildningsresultat (avgångsbetyg,<br/><br> <br/><br> matematik, Engelska, Svenska, idrott, medelbetyg) vid avgång från grundskolan. Födelseregistret (1973-86) länkades därvid med betygsregistret och 651 ungdomar med läppspalt, 830 med LKG-spalt samt 511 med gomspalt kunde jämföras med en kontroll grupp på 1 249 404 ungdomar utan spalt. Allt som allt noterade vi att ungdomar med LKG-spalt har en normal till en hög självkänsla och ingen märkbar skillnad i introversion (I). LKG påverkar de fysiska karaktärerna, särskilt inom gomspaltgruppen där vikt, längd, och muskelstyrka hade lägre mätvärden (II) och den något lägre prestationen i grundskolans idrottsämne<br/><br> <br/><br> kan ha samband med detta (IV). Den generella intellektuella kapaciteten (III) stödjer tidigare observationer att ungdomar med gomspalt som grupp betraktad har vissa kognitiva svårigheter medan den akademiska förmågan (IV) påverkade förmågan att hävda sig akademiskt påverkade alla inom LKG i någon utsträckning. https://portal.research.lu.se/en/publications/6e30e1f0-3ef3-4a15-8af7-abb864c0049b https://portal.research.lu.se/files/4779880/600478.pdf application/pdf 1840080 no Reconstructive Surgery 2007 eng self-concept introversion Surgery orthopaedics traumatology traumatologi ortopedi Kirurgi Psychiatry psychosocial cleft lip & palate clinical psychology psychosomatics Psykiatri klinisk psykologi psykosomatik Public health epidemiology Folkhälsa Psykologi Psychology epidemiologi psychology academic achievement muscle strength intellectual capacity weight statue Surgery 1652-8220 978-91-85897-17-9 599130 2007:139 98 2007-11-09T13:00:00+01:00 6e30e1f0-3ef3-4a15-8af7-abb864c0049b 2016-04-01T16:47:08+02:00 2025-04-04T14:16:51+02:00 2016-04-01T16:47:08+02:00 8 info:srw/schema/1/mods-v3.3xml journalArticle published yes 4 Martin Persson author 31ec7f7b-7095-4a14-8f05-798610ceff34 Gustaf Aniansson author Magnus Becker author 29d44712-dfc6-4f6c-9f58-5cc39b4925f8 Henry Svensson author c5f1e34e-754e-44d1-b42b-d99e4ea97159 Surgery v1000516 department Department of Clinical Sciences, Malmö v1000476 department Surgery research group The purpose of this study was to investigate if adolescents with cleft lip, or palate, or both (CLP), have an altered self-concept, and to assess their degree of introversion, compared with a control group. The CLP group consisted of 55 adolescents (aged 17-20 years) and the control group consisted of 31 adolescents (16-19 years). The Tennessee Self Concept Scale (TSCS) was used to measure the subjects' self-concept, while the Eysenck Personality Questionnaire Inventory (EPQ-I) was used to measure introversion. The results indicate that those with CLP have a normal or even a high self-concept, and no signs of introversion. https://portal.research.lu.se/en/publications/551396e5-ee94-48c9-9142-6d3fb55501b3 Medical Journals Sweden AB 2002 eng Surgery 1651-2073 105813 000174585300004 11925825 0036192978 10.1080/028443102753478336 http://dx.doi.org/10.1080/028443102753478336 yes 36 1 24 27 https://www.scopus.com/pages/publications/0036192978 The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Reconstructive Surgery (013240300), Surgery Research Unit (013242220), Emergency medicine/Medicine/Surgery (013240200) 551396e5-ee94-48c9-9142-6d3fb55501b3 2016-04-01T16:48:11+02:00 2025-10-14T10:01:08+02:00 2016-04-01T16:48:11+02:00 9 info:srw/schema/1/mods-v3.3xml journalArticle published yes 2 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 Solid State Physics v1000623 department We report a theoretical study of the electronic structure and optical properties of free-standing semiconductor nanowires, based on an atomistic tight-binding approach. It is shown that the optical transition between the valence-band maximum and conduction-band minimum of an intrinsic nanowire is fully polarized along the wire axis, and this giant polarization anisotropy can be explained in terms of intrinsic band-structure properties of the nanowire. It is also predicted that the optical spectra and polarization ratio of the nanowire can be tuned with temperature and the chemical potential of carriers in the nanowire. https://portal.research.lu.se/en/publications/7fb1dae9-9b31-4b6f-9168-0015bce1d43b American Physical Society 2004 eng Condensed Matter Physics (including Material Physics, Nano Physics) 1098-0121 262315 000224856000016 11244284964 10.1103/PhysRevB.70.161310 http://dx.doi.org/10.1103/PhysRevB.70.161310 yes 70 16 161310 https://www.scopus.com/pages/publications/11244284964 7fb1dae9-9b31-4b6f-9168-0015bce1d43b 2016-04-01T16:52:40+02:00 2025-10-14T10:34:46+02:00 2016-04-01T16:52:40+02:00 10 info:srw/schema/1/mods-v3.3xml journalArticle published yes 2 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 Solid State Physics v1000623 department We report on a theoretical study of the electronic structure of [100]-oriented free-standing III-V semiconductor nanowires with quadratic (square wire) and rectangular (nanobelt) cross-sections based on an atomistic tight-binding approach. It is shown that at the same cross-section aspect ratio, the characteristics of the band structure and state wave functions of the nanowires in the vicinity of the band edges are insensitive to variation of the lateral size, although the band energies show a strong dependence on the lateral size. It is also shown that the effective mass of the conduction bands of the nanowires is systematically enhanced with decrease of the nanowire size, and k(.)p analysis generally overestimates the effective mass enhancement. https://portal.research.lu.se/en/publications/e49dc7e9-a7b0-4e9e-a253-e9bc20527ec0 The American Chemical Society (ACS) 2004 eng Nano-technology 1530-6992 259160 000225681300019 10844254090 10.1021/nl0485049 http://dx.doi.org/10.1021/nl0485049 yes 4 12 2409 2414 https://www.scopus.com/pages/publications/10844254090 e49dc7e9-a7b0-4e9e-a253-e9bc20527ec0 2016-04-01T17:14:46+02:00 2025-10-14T12:20:51+02:00 2016-04-01T17:14:46+02:00 11 info:srw/schema/1/mods-v3.3xml journalArticle published yes 3 Martin Persson author 31ec7f7b-7095-4a14-8f05-798610ceff34 Magnus Becker author 29d44712-dfc6-4f6c-9f58-5cc39b4925f8 Henry Svensson author c5f1e34e-754e-44d1-b42b-d99e4ea97159 Surgery v1000516 department Surgery research group We report on the general intellectual capacity of men around 17-19 years of age and with cleft lip either with or without cleft palate (CLP) or cleft palate alone. Data were obtained from the Swedish National Service enrolment register for the years 1991-1997, about 335 individuals with CLP and 88 with cleft palate alone, who were compared with a control group consisting of 272 879 people. Those with CLP showed no significant differences compared with the control group. The group with cleft palate alone had significantly lower general intellectual scores than the control group. https://portal.research.lu.se/en/publications/5affd5fd-08ce-44df-bec8-06db41003c27 Medical Journals Sweden AB 2008 eng Surgery http://www.ncbi.nlm.nih.gov/pubmed/18188777?dopt=Abstract yes 1651-2073 1021475 18188777 000252356700003 38149024252 18188777 10.1080/02844310701694472 http://dx.doi.org/10.1080/02844310701694472 yes 42 1 14 16 https://www.scopus.com/pages/publications/38149024252 5affd5fd-08ce-44df-bec8-06db41003c27 2016-04-04T09:10:57+02:00 2025-10-14T13:26:53+02:00 2016-04-04T09:10:57+02:00 12 info:srw/schema/1/mods-v3.3xml theses published Lecture hall of Plant Physiology, Sölvegatan 35 1 Martin Persson author 7d40f14e-2e91-4ce1-bdca-289209a4d976 [unknown] [unknown] supervisor Prof Alexander von Gabain opponent Institute of Microbiology and Genetics, Vienna, Austria Department of Biology v1000601 department Genetic information, which is stored in DNA, is transferred to messenger RNA (mRNA) in a process called transcription. mRNAs are then translated by ribosomes into proteins which, with some important exceptions, catalyze chemical reactions in cells. Since cells must be able to adapt to changes in the environment, mRNAs must be unstable. The present investigation concerns mRNA degradation mainly in Bacillus subtilis, which is the model organism for Gram-positive bacteria. Comparative studies have also been performed in the Gram-negative Escherichia coli which is the best characterized bacterium concerning mRNA degradation. I have studied expression of the glpD gene, encoding glycerol-3-phosphate dehydrogenase, which is necessary for growth of B. subtilis on glycerol as the sole carbon and energy source. Previous studies have shown that expression of this gene is controlled by a protein, GlpP, which functions both as an antiterminator of transcription and an mRNA stabilizing protein in B. subtilis. The present investigation shows that GlpP binds to glpD mRNA both in vivo and in vitro. In E. coli, GlpP functions as an antiterminator protein but it does not stabilize glpD mRNA. The endoribonucleolytic cleavage pattern of glpD mRNA also differs between the two organisms and the major, RNase III-dependent, processing site found in E. coli is hardly detectable in B. subtilis. Furthermore, the secondary structure of the untranslated leader region of glpD mRNA has been determined both in vivo and in vitro. Based on these findings, a model for GlpP-mediated antitermination and mRNA stabilization is proposed. Studies have also been performed on the expression of the B. subtilis aprE gene, which encodes the excreted protease subtilisin. The results show that the extreme aprE mRNA stability is determined by the 5' region and is independent of growth phase. <b>Popular Abstract in Swedish</b><br/><br> Genetisk information lagras i DNA, som är en mycket stabil molekyl. I våra celler finns samma gener i alla celler. Det är därför av yttersta vikt att uttrycket av generna kan regleras olika i olika vävnader. Bakterier, som är encelliga organismer, måste för att kunna överleva noga kontrollera uttrycket av olika gener beroende på växlingar i omgivningen. Jag har studerat regleringen av två gener i Bacillus subtilis, som är en ofarlig bakterie som finns i hö och jord. Den ena genen (glpD) kodar för ett protein, som behövs för att bakterien skall kunna växa på glycerol, och proteinet skall därför bara produceras när glycerol är den bästa tillgängliga kol- och energikällan. Den andra genen (aprE) kodar för ett protein, som används för att bryta ner proteiner utanför bakterien och produceras bara när bakteriens tillväxt avstannar på grund av näringsbrist. Det finns ett mycket stort industriellt intresse för det sistnämnda proteinet, som ingår i bland annat moderna tvättmedel. En faktor som är av stor betydelse vid genreglering är hur länge den RNA kopia som görs av genen, den så kallade budbärar-RNA (mRNA)- molekylen, är funktionell. mRNA fungerar som mall för proteinsyntesen och ju längre det är funktionellt desto mer protein kan bakterien producera. I bakterier varierar livslängden för olika mRNA från 30 sekunder upp till en timme. Mitt arbete har visat att Bacillus subtilis och en tarmbakterie, Escherichia coli, bryter ner glpD mRNA på olika sätt. Vi har också visat att ett protein, som stabiliserar glpD mRNA i B. subtilis binder till en särskild del av detta mRNA. Vidare presenteras resultat som visar att de strukturer och sekvenser som bestämmer livslängden av såväl glpD som aprE mRNA ligger i den del av molekylen som syntetiseras först, den så kallade 5' regionen. https://portal.research.lu.se/en/publications/36081a57-91ce-4a05-8bd8-73b2b9e5faca Biology building 2000 eng Microbiology aprE GlpP glpD mRNA secondary structure Bacillus subtilis mRNA stability bacteriology virology mycology Mikrobiologi bakteriologi virologi mykologi Biological Sciences 91-628-4518-7 41071 ISRN: LUNBDS/NBNB-1038/1-45 (2000) 88 2000-12-01T10:00:00+01:00 The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Biology building (Closed 2011) (011008000) 36081a57-91ce-4a05-8bd8-73b2b9e5faca 2016-04-04T11:10:38+02:00 2025-04-04T15:26:23+02:00 2016-04-04T11:10:38+02:00 13 info:srw/schema/1/mods-v3.3xml conference paper published yes 2 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 Solid State Physics v1000623 department Proceedings of 7th International Conference on Nanometer-Scale Science and Technology and 21st European Conference on Surface Science (NANO-7/ECOSS-21) We report on a theoretical study of the electronic structure of semiconductor nanocrystals, based on a tight-binding method. Both one- and zero-dimensional structures have been studied. Concerning the one-dimensional structures, the effect of the confinement on the band structure of nanowires has been studied. We find that a transition from direct to indirect band gap occurs in the band structure as the size of the wire becomes smaller than a critical size. The effect is particularly prominent in the GaAs material. In the case of the zero-dimensional nanocrystals we have studied the effect of the confinement on the electronic structure of silicon. We show that the six-fold degenerate conduction band minima of the Si bulk crystal split into an A&lt;sub&gt;1&lt;/sub&gt; state, an E state and a T&lt;sub&gt;2&lt;/sub&gt; state. The ordering of these states is found to change with the size of the nanocrystal. The wave functions of the lowest unoccupied states and the highest occupied states of each symmetry have also been analyzed https://portal.research.lu.se/en/publications/2bd176ab-c263-46fa-968d-54b403f0f51b Lund University 2002 2002-06-24 - 2002-06-28 Malmö, Sweden eng nanometer sized semiconductor crystals electronic structure tight binding method zero dimensional structures one dimensional structures band structure nanowires indirect band gap GaAs material zero dimensional nanocrystals silicon Si GaAs T₂ state A₁ state E state Si bulk crystal six fold degenerate conduction band Condensed Matter Physics (including Material Physics, Nano Physics) 611840 2 2bd176ab-c263-46fa-968d-54b403f0f51b 2016-04-04T11:29:08+02:00 2025-04-04T14:35:21+02:00 2016-04-04T11:29:08+02:00 14 info:srw/schema/1/mods-v3.3xml conference paper published yes 2 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 Solid State Physics v1000623 department IEEE Conference on Nanotechnology We report a theoretical study of the electronic structure and optical properties of GaAs nanowires grown in the [111] direction with a hexagonal cross section, based on a tight-binding approach. It is shown that in the nanowires the degeneracy of the light-hole and heavy-hole bands at the Γ-point seen in the bulk material is lifted, and the light-hole state is located above the heavy-hole state, in strong contrast to the prediction by effective mass theory. The imaginary part of the dielectric function of the nanowires is also calculated and the absorption spectra is found to be strongly polarized https://portal.research.lu.se/en/publications/32416d76-8286-4153-aa4a-7699dd3c554f IEEE - Institute of Electrical and Electronics Engineers Inc. 2003 2003-08-12 - 2003-08-14 San Francisco, CA, United States eng effective mass theory hole state bulk material hole bands tight binding technique hexagonal cross section GaAs nanowires [111] direction optical properties electronic structure nanometer scale semiconductor wires GaAs absorption spectra nanowires polarization dielectric function Condensed Matter Physics (including Material Physics, Nano Physics) 0-7803-7976-4 612113 000185389900029 84943244022 10.1109/NANO.2003.1231727 http://dx.doi.org/10.1109/NANO.2003.1231727 yes 111 114 https://www.scopus.com/pages/publications/84943244022 32416d76-8286-4153-aa4a-7699dd3c554f 2016-04-04T11:56:27+02:00 2025-10-14T12:42:44+02:00 2016-04-04T11:56:27+02:00 15 info:srw/schema/1/mods-v3.3xml journalArticle published yes 2 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 Solid State Physics v1000623 department We report on a theoretical study of the electronic structure of free-standing InAs and InP nanowires grown along the [100] crystallographic direction, based on an atomistic tight-binding approach. The band structure and wave functions for nanowires with both square (nanowires) and rectangular (nanobelts) cross sections are calculated. A comparison is made between the calculations for InAs, InP, and GaAs nanowires and similar characteristics are found in the band structure and wave functions of the three material types of nanowires. It is found that the nanowires with both square and rectangular cross sections have simple, parabolic conduction bands. However, the characteristics of the valence bands in the nanowires are found to be cross-section aspect-ratio dependent. For the nanowires with a square cross section, the valence bands show rich and complex structures. In particular, the highest valence band of a square nanowire shows a double-maximum structure and has its energy maximum at k[not-equal]0, giving an indirect nanowire band gap. When the cross section of the nanowires changes from a square to a rectangular type, the top valence bands tend to develop into parabolic bands. For the nanowires with the same cross-section aspect ratio and material type, the valence band structures at different sizes are found to have similar characteristic structures, although the band energies sensitively depend on the nanowire lateral size. The wave functions of the band states of the InAs and InP nanowires at the Gamma point have been calculated. It is found that for the square nanowires the valence band states show complex structures. For the rectangular nanowires with sufficiently large aspect ratios the wave functions of the topmost valence band states show the features predicted by a one-band effective-mass model, in agreement with the fact that these valence bands become good parabolic bands in these rectangular nanowires. https://portal.research.lu.se/en/publications/49a900ee-2006-424c-993b-0101edd921fe American Physical Society 2006 eng Condensed Matter Physics (including Material Physics, Nano Physics) 806186 000236467400093 33645463193 10.1103/PhysRevB.73.125346 http://dx.doi.org/10.1103/PhysRevB.73.125346 yes 73 125346 https://www.scopus.com/pages/publications/33645463193 49a900ee-2006-424c-993b-0101edd921fe 2016-04-04T13:35:50+02:00 2025-10-14T10:30:27+02:00 2016-04-04T13:35:50+02:00 16 info:srw/schema/1/mods-v3.3xml conference abstract published yes 6 Elia Psouni author 28e364ac-451c-4c84-9931-6d725dd5f2e7 Andreas Falck author dbc8931e-e76c-40f6-bd6d-4b4f5b8fd11d Maria Wallin author c75d5c9a-5f78-4a7e-b2d4-23fde07f77f7 Lisa Siden author Leni Boström author Martin Persson author Department of Psychology v1000681 department Society for Research in Child Development (SRCD) Biennial Meeting 2015 https://portal.research.lu.se/en/publications/1217be75-c978-4255-bcfb-d5b92b7bccf6 2015 2015-03-19 - 2015-03-21 Philadelphia, United States eng Psychology 4937669 1217be75-c978-4255-bcfb-d5b92b7bccf6 2016-04-04T13:36:21+02:00 2025-04-04T15:25:34+02:00 2016-04-04T13:36:21+02:00 17 info:srw/schema/1/mods-v3.3xml conference paper published yes 2 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 Solid State Physics v1000623 department China Intl Conf on Nanosci and Technol, Beijing, China (2005) https://portal.research.lu.se/en/publications/41e5f46e-3085-4b2b-9b47-b59099789b26 2005 0001-01-02 eng Condensed Matter Physics (including Material Physics, Nano Physics) 962662 41e5f46e-3085-4b2b-9b47-b59099789b26 2016-04-04T13:47:33+02:00 2025-04-04T14:15:51+02:00 2016-04-04T13:47:33+02:00 18 info:srw/schema/1/mods-v3.3xml theses published Room B, Department of Physics, Sölvegatan 14, Lund Institute of Technology. 1 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 [unknown] [unknown] supervisor Professor Risto Nieminen opponent Helsinki University of Technology, Finland Solid State Physics v1000623 department In this thesis, the electronic structure and optical properties of semiconductor nanostructures are studied theoretically. Three types of nanostructures have been studied, silicon nanocrystals, free-standing III-V nanowires and free-standing GaAs/AlGaAs nanowire superlattices. The calculations have been carried out using an atomistic, empirical tight-binding approach.<br/><br> <br/><br> Silicon nanocrystals have attracted a great deal of attention after it was shown that they can emit visible light. In this thesis the highest occupied states and lowest unoccupied states of silicon nanocrystals are studied. The confinement energies of the states are calculated and the symmetries of the states are analyzed. To better understand the localization properties of the states, their wave functions are calculated and discussed.<br/><br> <br/><br> The major part of the work, contained within this thesis, regards calculations of the electronic structure and optical properties of free-standing nanowires. In all the cases studied the conduction bands of the nanowires show good parabolic dispersions. Also, the degeneracy of the light- and heavy-hole bands of the bulk material, is broken. The band structure for GaAs, InAs and InP nanowires, oriented along the [100] crystallographic direction, with square and rectangular cross-sections is studied. The effect of the cross-section aspect ratio is studied with regard to band structure and wave functions. For nanowires with a square cross-section the valence bands are found to show strongly non-parabolic dispersions. However, when the cross-section aspect ratio is increased, the dispersion of the bands become less non-parabolic. For large aspect ratios the topmost valence bands show good parabolic dispersion around the Brillouin zone center. In addition the optical properties of an InP [111]-oriented nanowire are studied, and the nanowire is found to have a strong optical polarization anisotropy. The band edge transition is found to be polarized parallel to the nanowire orientation.<br/><br> <br/><br> Lately, the model has been extended to handle the electronic structure of hetero-structured nanowires. In this thesis the band structure of [100]-oriented free-standing GaAs/AlGaAs nanowire superlattices is studied. The evolution of the band structure and the opening of band gaps in the valence and conduction bands are studied as a function of AlGaAs barrier thickness and nanowire lateral size. https://portal.research.lu.se/en/publications/4d83b9c1-d695-46ad-ac71-3880faa52164 2004 eng nanowire superlattices nanostructures band structure wavefunctions III-V materials optical properties Halvledarfysik Semiconductory physics Fysicumarkivet A:2004:Persson Tight-binding theory nanocrystals nanowires Condensed Matter Physics (including Material Physics, Nano Physics) 91-628-6320-7 467672 LUFTD2(TFFF-0075) 122 2004-12-16T10:15:00+01:00 <p> Article: Theoretical study of electronic structure of silicon nanocrystals,M.P. Persson and H.Q. Xu,Physica Scripta T101, 147 (2002) </p> <p> Article: Electronic structure of nanometer-scale GaAs whiskers,M.P. Persson and H.Q. Xu,Appl. Phys. Lett. 81, 1309, (2002) </p> <p> Article: Giant polarization anisotropy in optical transitions of free-standing InP nanowires,M.P. Persson and H.Q. Xu,Phys. Rev. B (Rapid Communications) 70, 161310 (2004) </p> <p> Article: Electronic structure of [100]-oriented free-standing semiconductor nanowires,M.P. Persson and H.Q. Xu,Accepted for publication in Nano Lett. </p> <p> Article: Electronic structure of [100]-oriented free-standing InAs and InP nanowires and nanobelts,M.P. Persson and H.Q. Xu,To be submitted to Phys. Rev. B </p> <p> Article: Electronic structure of GaAs/AlGaAs free-standing nanowire superlattices,M.P. Persson and H.Q. Xu,To be submitted to Nano Lett. </p> 4d83b9c1-d695-46ad-ac71-3880faa52164 2016-04-04T14:07:10+02:00 2025-04-04T14:56:30+02:00 2016-04-04T14:07:10+02:00 19 info:srw/schema/1/mods-v3.3xml journalArticle published yes 2 Martin Persson author f2d1e325-5541-427d-8b4f-526226ef8874 Hongqi Xu author c1a08ef8-a576-494c-aaed-afe3921ac183 Solid State Physics v1000623 department https://portal.research.lu.se/en/publications/ff1f96a8-0759-442b-8455-d279023cd1f4 American Physical Society 2006 eng Condensed Matter Physics (including Material Physics, Nano Physics) 806185 000235009500116 33144466115 10.1103/PhysRevB.73.035328 http://dx.doi.org/10.1103/PhysRevB.73.035328 yes 73 035328 https://www.scopus.com/pages/publications/33144466115 ff1f96a8-0759-442b-8455-d279023cd1f4 2016-04-04T14:22:14+02:00 2025-10-14T11:14:13+02:00 2016-04-04T14:22:14+02:00 20 1.1author exact "Persson, Martin"authorexactPersson, Martin