The perception of Mandarin speech conveying communicative functions in Chinese heroin addicts.

Drug addiction can cause severe damage to the human brain, leading to significant problems in cognitive processing, such as irritability, speech distortions, and exaggeration of negative stimuli. Speech plays a fundamental role in social interaction, including both the production and perception. The ability to perceive communicative functions conveyed through speech is crucial for successful interpersonal communication and the maintaining good social relationships. However, due to the limited number of previous studies, it remains unclear whether the cognitive disorder caused by drug addiction affects the perception of communicative function conveyed in Mandarin speech. To address this question, we conducted a perception experiment involving sixty male participants, including 25 heroin addicts and 35 healthy controls. The experiment aimed to examine the perception of three communicative functions (i.e., statement, interrogative, and imperative) under three background noise conditions (i.e., no noise, SNR [Signal to Noise Ratio] = 10, and SNR = 0). Eight target sentences were first recorded by two native Mandarin speakers for each of the three communicative functions. Each half was then combined with Gaussian White Noise under two background noise conditions (i.e., SNR = 10 and SNR = 0). Finally, 48 speech stimuli were included in the experiment with four options provided for perceptual judgment. The results showed that, under the three noise conditions, the average perceptual accuracies of the three communicative functions were 80.66% and 38% for the control group and the heroin addicts, respectively. Significant differences were found in the perception of the three communicative functions between the control group and the heroin addicts under the three noise conditions, except for the recognition of imperative under strong noise condition (i.e., SNR = 0). Moreover, heroin addicts showed good accuracy (around 50%) in recognizing imperative and poor accuracy (i.e., lower than the chance level) in recognizing interrogative. This paper not only fills the research gap in the perception of communicative functions in Mandarin speech among drug addicts but also enhances the understanding of the effects of drugs on speech perception and provides a foundation for the speech rehabilitation of drug addicts.

Acoustic Characteristics of Mandarin Speech in Male Drug Users.

AIM: Drug use/addiction has a profound impact on the physical and mental health of individuals. Previous studies have indicated that drug users may experience speech perception disorders, including speech illusion and challenges in recognizing emotional speech. However, the influence of drugs on speech production, as another crucial aspect of speech communication, has not been thoroughly examined. Therefore, the current study aimed to investigate how drugs affect the acoustic characteristics of speech in Chinese male drug users. METHOD: Speech recordings were collected from a total of 160 male drug users (including 106 heroin users, 23 ketamine users, and 31 methamphetamine users) and 55 male healthy controls with no history of drug use. Acoustic analysis was conducted on the collected speech data from these groups, and classification analysis was performed using five supervised learning algorithms. RESULTS: The results demonstrated that drug users exhibited smaller F0 standard deviation, reduced loudness, cepstral peak prominence, and formant relative energies, as well as higher H1-A3, longer unvoiced segments, and fewer voiced segments per second compared to the control group. The classification analyses yielded good performance in classifying drug users and non-drug users, with an accuracy above 86%. Moreover, the identification of the three groups of drug users achieved an accuracy of approximately 70%. Additionally, the study revealed different effects on speech production among the three types of drugs. CONCLUSION: The above findings indicate the presence of speech disorders, such as vocal hoarseness, in drug users, thus confirming the assumption that the acoustic characteristics of speech in drug users deviates from the norm. This study not only fills the knowledge gap regarding the effects of drugs on the speech production of Chinese male drug users but also provides a more comprehensive understanding of how drugs impact human behaviors. Furthermore, this research provides theoretical foundations of detoxification and speech rehabilitation for drug users.

The effects of face mask on speech production and its implication for forensic speaker identification-A cross-linguistic study.

This study aims to understand the effects of face mask on speech production between Mandarin Chinese and English, and on the automatic classification of mask/no mask speech and individual speakers. A cross-linguistic study on mask speech between Mandarin Chinese and English was then conducted. Continuous speech of the phonetically balanced texts in both Chinese and English versions were recorded from thirty native speakers of Mandarin Chinese (i.e., 15 males and 15 females) with and without wearing a surgical mask. The results of acoustic analyses showed that mask speech exhibited higher F0, intensity, HNR, and lower jitter and shimmer than no mask speech for Mandarin Chinese, whereas higher HNR and lower jitter and shimmer were observed for English mask speech. The results of classification analyses showed that, based on the four supervised learning algorithms (i.e., Linear Discriminant Analysis, Naïve Bayes Classifier, Random Forest, and Support Vector Machine), undesirable performances (i.e., lower than 50%) in classifying the speech with and without a face mask, and highly-variable accuracies (i.e., ranging from 40% to 89.2%) in identifying individual speakers were achieved. These findings imply that the speakers tend to conduct acoustic adjustments to improve their speech intelligibility when wearing surgical mask. However, a cross-linguistic difference in speech strategies to compensate for intelligibility was observed that Mandarin speech was produced with higher F0, intensity, and HNR, while English was produced with higher HNR. Besides, the highly-variable accuracies of speaker identification might suggest that surgical mask would impact the general performance of the accuracy of automatic speaker recognition. In general, therefore, it seems wearing a surgical mask would impact both acoustic-phonetic and automatic speaker recognition approaches to some extent, thus suggesting particular cautions in the real-case practice of forensic speaker identification.

Oxidation of dextran using H2O2 and NaClO/NaBr and their applicability in iron chelation.

The structural modification of polysaccharides directly affects their physicochemical properties and applications. Dextran, a chained polysaccharide, consists of multiple d-glucose molecules with repetitive structures. In this study, the physicochemical properties of oxidized dextran (DO) at different concentrations of NaClO/NaBr and H2O2 were compared. The results showed that NaClO/NaBr oxidation is more conducive to the formation of carboxyl groups. Oxidized dextran with NaClO/NaBr (DOB) showed good iron (III) chelating ability, and the DOB­iron (III) complex (DOBIC) had an iron content of 28.31%. According to structural analysis, NaClO/NaBr (2 g/100 g of active chlorine) and H2O2 (4 g/100 g), respectively, oxidize the C1 and C2 hydroxyl groups of dextran to carboxyl groups and open the ring when DO and iron have the strongest chelation ability. The complex is indeed a chelate iron complex, and iron core is composed of iron oxyhydroxide or the ß-FeOOH mineral polymorph. These results indicate that DOBIC is expected to be a good iron supplement or food additive to strengthen iron.

[Expression, purification, characterization and application of α-amino acid ester acyltransferase from recombinant Escherichia coli].

α-Amino acid ester acyltransferase (Aet) catalyzes the L-alanyl-L-glutamine forming reaction from L-alaine methylester hydrochloride and L-glutamine. In this study, the recombinant Escherichia coli saet-QC01 was used to express the α-amino acid acyltransferase, and its expression conditions were optimized. The recombinant protein was separated and purified by Ni-NTA affinity chromatography, and its enzymatic properties and catalytic applications were studied. The induction conditions suitable for enzyme production optimized were as follows: The temperature was 20 ℃, the induction stage (OD600=2.0-2.5), IPTG concentration was 0.6 mmol/L, induction time was 12 h. The optimal reaction conditions of α-amino acid acyltransferase were 27 ℃, pH 8.5, it was most stable between pH 7.0 and 8.0 and relatively stable in an acidic environment, and low concentration of Co²âº or EDTA could promote the enzyme activity. Under optimal reaction conditions, 600 mmol/L of L-alaine methylester hydrochloride and 480 mmol/L of L-glutamine, the yield of L-alanyl-L-glutamine reached 78.2 g/L and productivity of 1.955 g/L/min, the conversion rate reached 75.0%. α-Amino acid ester acyltransferase has excellent acid-basei resistance, high catalytic efficiency. These characteristics suggest its application prospects in the industrial production.

Assessment of signature handwriting evidence via score-based likelihood ratio based on comparative measurement of relevant dynamic features.

This paper extends on previous research on the extraction and statistical analysis on relevant dynamic features (width, grayscale and radian combined with writing sequence information) in forensic handwriting examinations. In this paper, a larger signature database was gathered, including genuine signatures, freehand imitation signatures, random forgeries and tracing imitation signatures, which are often encountered in casework. After applying Principle Component Analysis (PCA) of the variables describing the proximity between specimens, a two-dimensional kernel density estimation was used to describe the variability of within-genuine comparisons and genuine-forgery comparisons. We show that the overlap between the within-genuine comparisons and the genuine-forgery comparisons depends on the imitated writer and on the forger as well. Then, in order to simulate casework conditions, cases were simulated by random sampling based on the collected signature dataset. Three-dimensional normal density estimation was used to estimate the numerator and denominator probability distribution used to compute a likelihood ratio (LR). The comparisons between the performance of the systems in SigComp2011 (based on static features) and the method presented in this paper (based on relevant dynamic features) showed that relevant dynamic features are better than static features in terms of accuracy, false acceptance rate, false rejection rate and calibration of likelihood ratios.